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Sample records for models dosimetric quantities

  1. Intermediate dosimetric quantities.

    Science.gov (United States)

    Kellerer, A M; Hahn, K; Rossi, H H

    1992-04-01

    The transfer of energy from ionizing radiation to matter involves a series of steps. In wide ranges of their energy spectra photons and neutrons transfer energy to an irradiated medium almost exclusively by the production of charged particles which ionize and thereby produce electrons that can ionize in turn. The examination of these processes leads to a series of intermediate quantities. One of these is kerma, which has long been employed as a measure of the energy imparted in the first of the interactions. It depends only on the fluence of uncharged particles and is therefore--unlike absorbed dose and electron fluence--insensitive to local differences of receptor geometry and composition. An analogous quantity for charged-particle fields, cema (converted energy per unit mass), is defined, which quantifies the energy imparted in terms of the interactions of charged particles, disregarding energy dissipation by secondary electrons. Cema can be expressed as an integral over the fluence of ions times their stopping power. However, complications arise when the charged particles are electrons, and when their fluence cannot be separated from that of the secondaries. The resulting difficulty can be circumvented by the definition of reduced cema. This quantity corresponds largely to the concept employed in the cavity theory of Spencer and Attix. In reduced cema not all secondary electrons but all electrons below a chosen cutoff energy, delta, are considered to be absorbed locally. When the cutoff energy is reduced, cema approaches absorbed dose and thereby becomes sensitive to highly local differences in geometry or composition. With larger values of delta, reduced cema is a useful parameter to specify the dose-generating potential of a charged-particle field 'free in air' or in vacuo. It is nearly equal to the mean absorbed dose in a sphere with radius equal to the range of electrons of energy delta. Reduced cema is a function of the fluence at the specified location at

  2. A generalized definition of dosimetric quantities.

    Science.gov (United States)

    Kellerer, A M; Rossi, H H

    1990-04-01

    The current definitions of microdosimetric and dosimetric quantities use the notion of 'ionizing radiation'. However, this notion is not rigorously defined, and its definition would require the somewhat arbitrary choice of specified energy cut-off values for different types of particles. Instead of choosing fixed cut-off values one can extend the system of definitions by admitting the free selection of a category of types and energies of particles that are taken to be part of the field. In this way one extends the system of dosimetric quantities. Kerma and absorbed dose appear then as special cases of a more general dosimetric quantity, and an analogue to kerma can be obtained for charged particle fields; it is termed cema. A modification that is suitable for electron fields is termed reduced cema.

  3. Determination of dosimetric quantities in pediatric abdominal computed tomography scans

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    Jornada, Tiago da Silva [Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina. Dept. de Diagnostipo por Imagem; Silva, Teogenes Augusto da, E-mail: silvata@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2014-09-15

    Objective: aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods: the study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results: No significant difference was observed in the values for weighted air kerma index (C{sub W}), but the differences were relevant in values for volumetric air kerma index (C{sub VOL}), air kerma-length product (P{sub KL,CT}) and effective dose. Conclusion: Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, P{sub KL,CT} and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. (author)

  4. Determination of dosimetric quantities in pediatric abdominal computed tomography scans*

    Science.gov (United States)

    Jornada, Tiago da Silva; da Silva, Teógenes Augusto

    2014-01-01

    Objective Aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods The study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results No significant difference was observed in the values for weighted air kerma index (CW), but the differences were relevant in values for volumetric air kerma index (CVOL), air kerma-length product (PKL,CT) and effective dose. Conclusion Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, PKL,CT and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. PMID:25741103

  5. Practical simplifications for radioimmunotherapy dosimetric models

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    Shen, S.; DeNardo, G.L.; O`Donnell, R.T.; Yuan, A.; DeNardo, D.A.; Macey, D.J.; DeNardo, S.J. [Univ. of California, Sacramento, CA (United States). Davis Medical Center

    1999-01-01

    Radiation dosimetry is potentially useful for assessment and prediction of efficacy and toxicity for radionuclide therapy. The usefulness of these dose estimates relies on the establishment of a dose-response model using accurate pharmacokinetic data and a radiation dosimetric model. Due to the complexity in radiation dose estimation, many practical simplifications have been introduced in the dosimetric modeling for clinical trials of radioimmunotherapy. Although research efforts are generally needed to improve the simplifications used at each stage of model development, practical simplifications are often possible for specific applications without significant consequences to the dose-response model. In the development of dosimetric methods for radioimmunotherapy, practical simplifications in the dosimetric models were introduced. This study evaluated the magnitude of uncertainty associated with practical simplifications for: (1) organ mass of the MIRD phantom; (2) radiation contribution from target alone; (3) interpolation of S value; (4) macroscopic tumor uniformity; and (5) fit of tumor pharmacokinetic data.

  6. Evaluation of specific absorption rate as a dosimetric quantity for electromagnetic fields bioeffects.

    Directory of Open Access Journals (Sweden)

    Dimitris J Panagopoulos

    Full Text Available PURPOSE: To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. METHODS: We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect. RESULTS: WE FIND THAT: a The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured. CONCLUSIONS: SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar

  7. Topological detector: measuring continuous dosimetric quantities with few-element detector array.

    Science.gov (United States)

    Han, Zhaohui; Brivio, Davide; Sajo, Erno; Zygmanski, Piotr

    2016-08-21

    A prototype topological detector was fabricated and investigated for quality assurance of radiation producing medical devices. Unlike a typical array or flat panel detector, a topological detector, while capable of achieving a very high spatial resolution, consists of only a few elements and therefore is much simpler in construction and more cost effective. The key feature allowing this advancement is a geometry-driven design that is customized for a specific dosimetric application. In the current work, a topological detector of two elements was examined for the positioning verification of the radiation collimating devices (jaws, MLCs, and blades etc). The detector was diagonally segmented from a rectangular thin film strip (2.5 cm  ×  15 cm), giving two contiguous but independent detector elements. The segmented area was the central portion of the strip measuring 5 cm in length. Under irradiation, signals from each detector element were separately digitized using a commercial multichannel data acquisition system. The center and size of an x-ray field, which were uniquely determined by the collimator positions, were shown mathematically to relate to the difference and sum of the two signals. As a proof of concept, experiments were carried out using slit x-ray fields ranging from 2 mm to 20 mm in size. It was demonstrated that, the collimator positions can be accurately measured with sub-millimeter precisions.

  8. Topological detector: measuring continuous dosimetric quantities with few-element detector array

    Science.gov (United States)

    Han, Zhaohui; Brivio, Davide; Sajo, Erno; Zygmanski, Piotr

    2016-08-01

    A prototype topological detector was fabricated and investigated for quality assurance of radiation producing medical devices. Unlike a typical array or flat panel detector, a topological detector, while capable of achieving a very high spatial resolution, consists of only a few elements and therefore is much simpler in construction and more cost effective. The key feature allowing this advancement is a geometry-driven design that is customized for a specific dosimetric application. In the current work, a topological detector of two elements was examined for the positioning verification of the radiation collimating devices (jaws, MLCs, and blades etc). The detector was diagonally segmented from a rectangular thin film strip (2.5 cm  ×  15 cm), giving two contiguous but independent detector elements. The segmented area was the central portion of the strip measuring 5 cm in length. Under irradiation, signals from each detector element were separately digitized using a commercial multichannel data acquisition system. The center and size of an x-ray field, which were uniquely determined by the collimator positions, were shown mathematically to relate to the difference and sum of the two signals. As a proof of concept, experiments were carried out using slit x-ray fields ranging from 2 mm to 20 mm in size. It was demonstrated that, the collimator positions can be accurately measured with sub-millimeter precisions.

  9. A critical review of {sup 55}Fe dosimetric models

    Energy Technology Data Exchange (ETDEWEB)

    Thind, K.S. [Ontario Hydro Nuclear, Whitby, Ontario (Canada)

    1995-01-01

    The available literature on {sup 55}Fe dosimetry has been devoted to environmental exposures and medical iron kinetic studies. For occupational dosimetry, ICRP published a non-recycling dosimetric model for iron. These ICRP publications do not provide information on iron excretion. Johnson and Dunford published dose conversion factors and urinary excretion curves based on the ICRP and MIRD iron metabolic models. A critical review of these models was undertaken to select a model for occupational dose assignment. The review indicated that the information and recommendations in ICRP and Johnson and Dunford are dependent on unrealistic assumptions that do not agree with known iron metabolism. Therefore, an alternative model is proposed for dosimetric application. Calculations of dose conversion factors and urinary excretion curve for class W{sup 55}Fe inhalation exposure (1 {mu}m AMAD) using the proposed model are compared with predictions based on ICRP and Johnson and Dunford models. The difference in the practical outcome (i.e., dose assignment) is examined by applying the proposed and reviewed models to a realistic bioassay case. The Johnson and Dunford model yields a dose estimate which is roughly a factor of ten higher than values predicted by ICRP and the proposed model. Some of the disagreement is due to uncertainty in the fraction of radio-iron excretion via urine. Further research on this subject is recommended. In the interim, the proposed model is recommended for occupational dose assignment. 31 refs., 6 figs., 9 tabs.

  10. A biokinetic and dosimetric model for ionic indium in humans

    Science.gov (United States)

    Andersson, Martin; Mattsson, Sören; Johansson, Lennart; Leide-Svegborn, Sigrid

    2017-08-01

    This paper reviews biokinetic data for ionic indium, and proposes a biokinetic model for systemic indium in adult humans. The development of parameter values focuses on human data and indium in the form of ionic indium(III), as indium chloride and indium arsenide. The model presented for systemic indium is defined by five different pools: plasma, bone marrow, liver, kidneys and other soft tissues. The model is based on two subsystems: one corresponding to indium bound to transferrin and one where indium is transported back to the plasma, binds to red blood cell transferrin and is then excreted through the kidneys to the urinary bladder. Absorbed doses to several organs and the effective dose are calculated for 111In- and 113mIn-ions. The proposed biokinetic model is compared with previously published biokinetic indium models published by the ICRP. The absorbed doses are calculated using the ICRP/ICRU adult reference phantoms and the effective dose is estimated according to ICRP Publication 103. The effective doses for 111In and 113mIn are 0.25 mSv MBq-1 and 0.013 mSv MBq-1 respectively. The updated biokinetic and dosimetric models presented in this paper take into account human data and new animal data, which represent more detailed and presumably more accurate dosimetric data than that underlying previous models for indium.

  11. Biologic data, models, and dosimetric methods for internal emitters

    Energy Technology Data Exchange (ETDEWEB)

    Weber, D.A.

    1990-01-01

    The absorbed radiation dose from internal emitters has been and will remain a pivotal factor in assessing risk and therapeutic utility in selecting radiopharmaceuticals for diagnosis and treatment. Although direct measurements of absorbed dose and dose distributions in vivo have been and will continue to be made in limited situations, the measurement of the biodistribution and clearance of radiopharmaceuticals in human subjects and the use of this data is likely to remain the primary means to approach the calculation and estimation of absorbed dose from internal emitters over the next decade. Since several approximations are used in these schema to calculate dose, attention must be given to inspecting and improving the application of this dosimetric method as better techniques are developed to assay body activity and as more experience is gained in applying these schema to calculating absorbed dose. Discussion of the need for considering small scale dosimetry to calculate absorbed dose at the cellular level will be presented in this paper. Other topics include dose estimates for internal emitters, biologic data mathematical models and dosimetric methods employed. 44 refs.

  12. Analysis of superficial fluorescence patterns in nonmelanoma skin cancer during photodynamic therapy by a dosimetric model

    Science.gov (United States)

    Salas-García, I.; Fanjul-Vélez, F.; Arce-Diego, J. L.

    2016-03-01

    In this work the superficial fluorescence patterns in different nonmelanoma skin cancers and their photodynamic treatment response are analysed by a fluorescence based dosimetric model. Results show differences of even more than 50% in the fluorescence patterns as photodynamic therapy progresses depending on the malignant tissue type. They demonstrate the great relevance of the biological media as an additional dosimetric factor and contribute to the development of a future customized therapy with the assistance of dosimetric tools to interpret the fluorescence images obtained during the treatment monitoring and the differential photodiagnosis.

  13. Estimating dosimetric quantities of radon progeny using human CT scan data and small tissue volume analysis with Geant4 code system

    Directory of Open Access Journals (Sweden)

    Van Den Akker Evelynn

    2015-01-01

    Full Text Available Estimating the health effects of radon exposure is of great interest because radon is considered the second leading cause of lung cancer after smoking. The dose-response curve is not well understood at low-dose levels where radon exposure is estimated. Therefore, the health mechanisms of radiation due to radon progeny at the cellular and molecular levels are of interest for providing an indication of a possible threshold value above which the exposure may indicate cancer formation. In this paper we present a macroscopic and cellular level numerical analysis of the radon-induced dose estimates based on the Geant4 code system. Macroscopic estimates are assessed based on patient-specific computer tomography scans that provide geometries easily applicable to modeling radiation effects of the radon progeny sources. A small tissue volumes analysis based on the Geant4 code system is developed so as to provide information about the interactions and particle track structures at the microscopic (cellular levels producing the dosimetric effects of radon short-lived progenies. The results presented in this paper also call attention to the capabilities of Geant4 to provide radon-related dosimetric parameters of large and small-scale biological systems.

  14. Impact of festival factor on electric quantity multiplication forecast model

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This research aims to improve the forecasting precision of electric quantity. It is discovered that the total electricity consumption considerably increased during the Spring Festival by the analysis of the electric quantity time series from 2002 to 2007 in Shandong province. The festival factor is ascertained to be one of the important seasonal factors affecting the electric quantity fluctuations, and the multiplication model for forecasting is improved by introducing corresponding variables and parameters...

  15. Dosimetric Significance of the ICRP's Updated Guidance and Models, 1989-2003, and Implications for U.S. Federal Guidance

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, R.W.

    2003-09-10

    Over the past two decades the U.S. Environmental Protection Agency (EPA) has issued a series of Federal guidance documents for the purpose of providing the Federal and State agencies with technical information to assist their implementation of radiation protection programs. Currently recommended dose conversion factors, annual limits on intake, and derived air concentrations for intake of radionuclides are tabulated in Federal Guidance Report No. 11 (FGR 11), published in 1988. The tabulations in FGR 11 were based on dosimetric quantities and biokinetic and dosimetric models of the International Commission on Radiological Protection (ICRP) developed for application to occupational exposures. Since the publication of FGR 11 the ICRP has revised some of its dosimetric quantities and its models for workers and has also developed age-specific models and dose conversion factors for intake of radionuclides by members of the public. This report examines the extent of the changes in the inhalation and ingestion dose coefficients of FGR 11 implied by the updated recommendations of the ICRP, both for workers and members of the public.

  16. Study of dosimetric quantities and image quality in pediatric examinations of chest and abdomen computed tomography; Estudo das grandezas dosimetricas e da qualidade da imagem em exames pediatricos de torax e abdomen por tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Jornada, Tiago da Silva

    2013-08-01

    This work had the objective to achieve the knowledge of the dosimetric quantities related to chest and abdomen computed tomography (CT) examinations of pediatric patients, in Belo Horizonte city. The reason of this work is based on the fact that the probability of health detriment in children, which it may be caused by radiation, is higher than in adults. Besides, although in many countries the knowledge and control of patient doses is a normal procedure, this safety culture does not exist in Brazil. Another objective of this work was to compare the dosimetric quantity values with the Diagnostic Reference Levels (DRLs); when it was needed, an optimization process was applied and the quality of the diagnostic image obtained with the optimized technical parameters was analyzed. This study was carried out in five hospitals, where the weighted air kerma index (Cw), the volumetric air kerma index (Cvol), the air kerma - length product (PKL,CT), the Effective Dose (E) and the Normalized Effective Dose (En) were determined; three methods were adopted for measurements: the ionization chamber inside a chest pediatric phantom, radiochromic films and the CT-EXPO software. The optimization process was applied to a single hospital through variations in the current (mA) and voltage (kV) of the x-ray tube for the protocols used for abdomen CT examinations. The analysis of the quality of the diagnostic image was done by Normal Distribution and ROC analysis; spatial resolution analysis was used through MTF determination and the noise level was judged in terms quantitative and qualitative. Results of the dosimetric quantities showed that they significantly differed between single-slice and multi-slice tomography units, but their values were always below the recommended DRLs. The optimized values of the dosimetric quantities obtained after the optimization process showed that it was possible to reduce the radiation exposure of pediatric patient without losing the image quality

  17. Conceptual Model of Quantities, Units, Dimensions, and Values

    Science.gov (United States)

    Rouquette, Nicolas F.; DeKoenig, Hans-Peter; Burkhart, Roger; Espinoza, Huascar

    2011-01-01

    JPL collaborated with experts from industry and other organizations to develop a conceptual model of quantities, units, dimensions, and values based on the current work of the ISO 80000 committee revising the International System of Units & Quantities based on the International Vocabulary of Metrology (VIM). By providing support for ISO 80000 in SysML via the International Vocabulary of Metrology (VIM), this conceptual model provides, for the first time, a standard-based approach for addressing issues of unit coherence and dimensional analysis into the practice of systems engineering with SysML-based tools. This conceptual model provides support for two kinds of analyses specified in the International Vocabulary of Metrology (VIM): coherence of units as well as of systems of units, and dimension analysis of systems of quantities. To provide a solid and stable foundation, the model for defining quantities, units, dimensions, and values in SysML is explicitly based on the concepts defined in VIM. At the same time, the model library is designed in such a way that extensions to the ISQ (International System of Quantities) and SI Units (Systeme International d Unites) can be represented, as well as any alternative systems of quantities and units. The model library can be used to support SysML user models in various ways. A simple approach is to define and document libraries of reusable systems of units and quantities for reuse across multiple projects, and to link units and quantity kinds from these libraries to Unit and QuantityKind stereotypes defined in SysML user models.

  18. On the Economic Order Quantity Model With Transportation Costs

    NARCIS (Netherlands)

    S.I. Birbil (Ilker); K. Bulbul; J.B.G. Frenk (Hans); H.M. Mulder (Henry)

    2009-01-01

    textabstractWe consider an economic order quantity type model with unit out-of-pocket holding costs, unit opportunity costs of holding, fixed ordering costs and general transportation costs. For these models, we analyze the associated optimization problem and derive an easy procedure for determining

  19. Fuzzy Economic Order Quantity Inventory Models Without Backordering

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaobin; TANG Wansheng; ZHAO Ruiqing

    2007-01-01

    In economic order quantity models without backordering, both the stock cost of each unit quantity and the order cost of each cycle are characterized as independent fuzzy variables rather than fuzzy numbers as in previous studies. Based on an expected value criterion or a credibility criterion, a fuzzy expected value model and a fuzzy dependent hance programming (DCP) model are constructed. The purpose of the fuzzy expected value model is to find the optimal order quantity such that the fuzzy expected value of the total cost is minimal. The fuzzy DCP model is used to find the optimal order quantity for maximizing the credibility of an event such that the total cost in the planning periods does not exceed a certain budget level.Fuzzy simulations are designed to calculate the expected value of the fuzzy objective function and the credibility of each fuzzy event. A particle swarm optimization (PSO) algorithm based on a fuzzy simulation is designed, by integrating the fuzzy simulation and the PSO algorithm. Finally, a numerical example is given to illustrate the feasibility and validity of the proposed algorithm.

  20. Dosimetric treatment course simulation based on a statistical model of deformable organ motion.

    Science.gov (United States)

    Söhn, M; Sobotta, B; Alber, M

    2012-06-21

    We present a method of modeling dosimetric consequences of organ deformation and correlated motion of adjacent organ structures in radiotherapy. Based on a few organ geometry samples and the respective deformation fields as determined by deformable registration, principal component analysis (PCA) is used to create a low-dimensional parametric statistical organ deformation model (Söhn et al 2005 Phys. Med. Biol. 50 5893-908). PCA determines the most important geometric variability in terms of eigenmodes, which represent 3D vector fields of correlated organ deformations around the mean geometry. Weighted sums of a few dominating eigenmodes can be used to simulate synthetic geometries, which are statistically meaningful inter- and extrapolations of the input geometries, and predict their probability of occurrence. We present the use of PCA as a versatile treatment simulation tool, which allows comprehensive dosimetric assessment of the detrimental effects that deformable geometric uncertainties can have on a planned dose distribution. For this, a set of random synthetic geometries is generated by a PCA model for each simulated treatment course, and the dose of a given treatment plan is accumulated in the moving tissue elements via dose warping. This enables the calculation of average voxel doses, local dose variability, dose-volume histogram uncertainties, marginal as well as joint probability distributions of organ equivalent uniform doses and thus of TCP and NTCP, and other dosimetric and biologic endpoints. The method is applied to the example of deformable motion of prostate/bladder/rectum in prostate IMRT. Applications include dosimetric assessment of the adequacy of margin recipes, adaptation schemes, etc, as well as prospective 'virtual' evaluation of the possible benefits of new radiotherapy schemes.

  1. The revised International Commission on Radiological Protection (ICRP) dosimetric model for the human respiratory tract

    Energy Technology Data Exchange (ETDEWEB)

    Bair, W.J.

    1992-05-01

    A task group has revised the dosimetric model of the respiratory tract used to calculate annual limits on intake of radionuclides. The revised model can be used to project respiratory tract doses for workers and members of the public from airborne radionuclides and to assess past exposures. Doses calculated for specific extrathoracic and thoracic tissues can be adjusted to account for differences in radiosensitivity and summed to yield two values of dose for the respiratory tract that are applicable to the ICRP tissue weighted dosimetry system.

  2. A Combined Tissue Kinetics and Dosimetric Model of Respiratory Tissue Exposed to Radiation

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    John R. Ford

    2005-11-01

    Existing dosimetric models of the radiation response of tissues are essentially static. Consideration of changes in the cell populations over time has not been addressed realistically. For a single acute dose this is not a concern, but for modeling chronic exposures or fractionated acute exposures, the natural turnover and progression of cells could have a significant impact on a variety of endpoints. This proposal addresses the shortcomings of current methods by combining current dose-based calculation techniques with information on the cell turnover for a model tissue. The proposed model will examine effects at the single-cell level for an exposure of a section of human bronchiole. The cell model will be combined with Monte Carlo calculations of doses to cells and cell nuclei due to varying dose-rates of different radiation qualities. Predictions from the model of effects on survival, apoptosis rates, and changes in the number of cycling and differentiating cells will be tested experimentally. The availability of dynamic dosimetric models of tissues at the single-cell level will be useful for analysis of low-level radiation exposures and in the development of new radiotherapy protocols.

  3. Study of dosimetric quantities applied to patient undergoing routine chest examinations by computed tomography; Estudo de grandezas dosimetricas aplicadas em pacientes submetidos a exames de torax rotina em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Gonzaga, Natalia Barbosa

    2012-07-01

    The radiological protection system has established a standard to protect persons against the harmful effects caused by ionizing radiation that is based on the justification, optimization and dose limitation principles. The increasing use of radiation in medicine and the related risks have stressed the discussion on patient radiation protection. The computed tomography (CT) is the diagnostic radiology technique that most contributes to patient doses and it requires optimization efforts. Diagnostic reference levels (DRL) has been established in many countries in terms of CT dosimetric quantities; in Brazil, the DRLs are still under investigation since the culture of patient protection is not very strong yet. The objective of this work was to investigate the dosimetric and protection quantities related to patients undergoing CT routine chest examinations. The ImPACT CT, CT Expo and ImpactDose softwares were used for calculations of the weight and volumetric air-kerma indexes (CW and CVOL), the air kerma - length product (P{sub K,L}), organ equivalent dose (H{sub T}) and the effective dose (E) for CT routine chest protocols in 19 tomographs in Belo Horizonte city. The CT Expo was selected to be validated against experimental measurements in three hospitals with thermoluminescent dosimeters and CT pencil ionization chamber in anthropomorphic and standard CT body phantoms. Experimental and calculated results indicated differences up to 97% for H{sub T} and E and acceptable agreement for C{sub W} ,C{sub VOL} and P{sub K,L}. All data from 19 tomographs showed that local DRLs for CT routine chest examinations may be chosen smaller than DRLs adopted in other countries; this would contribute to increase the radiological protection of patients. (author)

  4. Evaluating the uncertainty of input quantities in measurement models

    Science.gov (United States)

    Possolo, Antonio; Elster, Clemens

    2014-06-01

    The Guide to the Expression of Uncertainty in Measurement (GUM) gives guidance about how values and uncertainties should be assigned to the input quantities that appear in measurement models. This contribution offers a concrete proposal for how that guidance may be updated in light of the advances in the evaluation and expression of measurement uncertainty that were made in the course of the twenty years that have elapsed since the publication of the GUM, and also considering situations that the GUM does not yet contemplate. Our motivation is the ongoing conversation about a new edition of the GUM. While generally we favour a Bayesian approach to uncertainty evaluation, we also recognize the value that other approaches may bring to the problems considered here, and focus on methods for uncertainty evaluation and propagation that are widely applicable, including to cases that the GUM has not yet addressed. In addition to Bayesian methods, we discuss maximum-likelihood estimation, robust statistical methods, and measurement models where values of nominal properties play the same role that input quantities play in traditional models. We illustrate these general-purpose techniques in concrete examples, employing data sets that are realistic but that also are of conveniently small sizes. The supplementary material available online lists the R computer code that we have used to produce these examples (stacks.iop.org/Met/51/3/339/mmedia). Although we strive to stay close to clause 4 of the GUM, which addresses the evaluation of uncertainty for input quantities, we depart from it as we review the classes of measurement models that we believe are generally useful in contemporary measurement science. We also considerably expand and update the treatment that the GUM gives to Type B evaluations of uncertainty: reviewing the state-of-the-art, disciplined approach to the elicitation of expert knowledge, and its encapsulation in probability distributions that are usable in

  5. Fuzzy economic production quantity model with time dependent demand rate

    Directory of Open Access Journals (Sweden)

    Susanta Kumar Indrajitsingha

    2016-09-01

    Full Text Available Background: In this paper, an economic production quantity model is considered under a fuzzy environment. Both the demand cost and holding cost are considered using fuzzy pentagonal numbers. The Signed Distance Method is used to defuzzify the total cost function. Methods: The results obtained by these methods are compared with the help of a numerical example. Sensitivity analysis is also carried out to explore the effect of changes in the values of some of the system parameters. Results and conclusions: The fuzzy EPQ model with time dependent demand rate was presented together with the possible implementation. The behavior of changes in parameters was analyzed. The possible extension of the implementation of this method was presented.

  6. Dosimetric analysis of 123I, 125I and 131I in thyroid follicle models

    Science.gov (United States)

    2014-01-01

    Background Radioiodine is routinely used or proposed for diagnostic and therapeutic purposes: 123I, 125I and 131I for diagnostics and 125I and 131I for therapy. When radioiodine-labelled pharmaceuticals are administered to the body, radioiodide might be released into the circulation and taken up by the thyroid gland, which may then be an organ at risk. The aim of this study was to compare dosimetric properties for 123I, 125I and 131I in previously developed thyroid models for man, rat and mouse. Methods Dosimetric calculations were performed using the Monte Carlo code MCNPX 2.6.0 and nuclear decay data from ICRP 107. Only the non-radiative transitions in the decays were considered. The S value was determined for the cell nuclei in species-specific thyroid follicle models for mouse, rat and man for different spatial distributions of radioiodine. Results For the species-specific single follicle models with radioiodine homogeneously within the follicle lumen, the highest S value came from 131I, with the largest contribution from the β particles. When radioiodine was homogeneously distributed within the follicle cells or the follicle cell nucleus, the highest contribution originated from 125I, about two times higher than 123I, with the largest contribution from the Auger electrons. The mean absorbed dose calculated for our human thyroid multiple follicle model, assuming homogenous distribution of for 123I, 125I, or 131I within the follicle lumens and follicle cells, was 9%, 18% and 4% higher, respectively, compared with the mean absorbed dose according to Medical Internal Radiation Dose (MIRD) formalism and nuclear decay data. When radioiodine was homogeneously distributed in the follicle lumens, our calculations gave up to 90% lower mean absorbed dose for 125I compared to MIRD (20% lower for 123I, and 2% lower for 131I). Conclusions This study clearly demonstrates the importance of using more detailed dosimetric methods and models than MIRD formalism for radioiodine

  7. Dosimetric comparison between model 9011 and 6711 sources in prostate implants.

    Science.gov (United States)

    Zhang, Hualin; Beyer, David

    2013-01-01

    The purpose of this work is to evaluate the model 9011 iodine-125 ((125)I) in prostate implants by comparing dosimetric coverage provided by the 6711 vs 9011 source implants. Postimplant dosimetry was performed in 18 consecutively implanted patients with prostate cancer. Two were implanted with the 9011 source and 16 with the 6711 source. For purposes of comparison, each implant was then recalculated assuming use of the other source. The same commercially available planning system was used and the specific source data for both 6711 and 9011 products were entered. The results of these calculations are compared side by side in the terms of the isodose values covering 100% (D100) and 90% (D90) of prostate volume, and the percentages of volumes of prostate, bladder, rectum, and urethra covered by 200% (V200), 150% (V150), 100% (V100), 50% (V50), and 20% (V20) of the prescribed dose as well. The 6711 source data overestimate coverage by 6.4% (ranging from 4.9% to 6.9%; median 6.6%) at D100 and by 6.6% (ranging from 6.2% to 6.8%; median 6.6%) at D90 compared with actual 9011 data. Greater discrepancies of up to 67% are seen at higher dose levels: average reduction for V100 is 2.7% (ranging from 0.6% to 7.7%; median 2.3%), for V150 is 14.6% (ranging from 6.1% to 20.5%; median 15.3%), for V200 is 14.9% (ranging from 4.8% to 19.1%; median 16%); similarly seen in bladder, rectal, and urethral coverage. This work demonstrates a clear difference in dosimetric behavior between the 9011 and 6711 sources. Using the 6711 source data for 9011 source implants would create a pronounced error in dose calculation. This study provides evidence that the 9011 source can provide the same dosimetric quality as the 6711 source, if properly used; however, the 6711 source data should not be considered as a surrogate for the 9011 source implants. Copyright © 2013 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  8. Dosimetric comparison between model 9011 and 6711 sources in prostate implants

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hualin, E-mail: zhang248@iupui.edu [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); Arizona Oncology Services, Phoenix, AZ (United States); Beyer, David [Arizona Oncology Services, Phoenix, AZ (United States)

    2013-07-01

    The purpose of this work is to evaluate the model 9011 iodine-125 ({sup 125}I) in prostate implants by comparing dosimetric coverage provided by the 6711 vs 9011 source implants. Postimplant dosimetry was performed in 18 consecutively implanted patients with prostate cancer. Two were implanted with the 9011 source and 16 with the 6711 source. For purposes of comparison, each implant was then recalculated assuming use of the other source. The same commercially available planning system was used and the specific source data for both 6711 and 9011 products were entered. The results of these calculations are compared side by side in the terms of the isodose values covering 100% (D100) and 90% (D90) of prostate volume, and the percentages of volumes of prostate, bladder, rectum, and urethra covered by 200% (V200), 150% (V150), 100% (V100), 50% (V50), and 20% (V20) of the prescribed dose as well. The 6711 source data overestimate coverage by 6.4% (ranging from 4.9% to 6.9%; median 6.6%) at D100 and by 6.6% (ranging from 6.2% to 6.8%; median 6.6%) at D90 compared with actual 9011 data. Greater discrepancies of up to 67% are seen at higher dose levels: average reduction for V100 is 2.7% (ranging from 0.6% to 7.7%; median 2.3%), for V150 is 14.6% (ranging from 6.1% to 20.5%; median 15.3%), for V200 is 14.9% (ranging from 4.8% to 19.1%; median 16%); similarly seen in bladder, rectal, and urethral coverage. This work demonstrates a clear difference in dosimetric behavior between the 9011 and 6711 sources. Using the 6711 source data for 9011 source implants would create a pronounced error in dose calculation. This study provides evidence that the 9011 source can provide the same dosimetric quality as the 6711 source, if properly used; however, the 6711 source data should not be considered as a surrogate for the 9011 source implants.

  9. Ship waste quantities prediction model for the port of Belgrade

    Directory of Open Access Journals (Sweden)

    VLADANKA PRESBURGER ULNIKOVIĆ

    2011-06-01

    Full Text Available This study focuses on the issues related to the waste management in river ports in general and especially in the port of Belgrade. Data on solid waste, waste oils, oily waters, gray water and black water have been collected for a period of five years. The methodology of data collection is presented. Trends of data were analyzed and the regression model was used to predict the waste quantities in the Belgrade port. This data could be utilized as a basis for the calculation of the equipment capacity for waste selective collection, treatment and storage. The results presented in this study establish the need for an orga¬nized management system for this type of waste which can be achieved either by constructing and providing new specialized terminal or by providing mobile floating facilities and other plants in the Port of Belgrade for these kinds of ser¬vices. In addition to the above, the legislative and organizational strategy of waste management has been explored to complete the study because the im¬pact of good waste management on environment and prevention of environ¬mental accidents would be highly beneficial. This study demonstrated that ad¬dressing these issues should be considered at international as well as national level.

  10. A modelling study of regional deposition of inspired aerosols with reference to dosimetric assessments

    Energy Technology Data Exchange (ETDEWEB)

    Egan, M.J.; Nixon, W. (UKAEA Safety and Reliability Directorate, Culcheth (UK))

    1988-01-01

    An improved lung deposition model, agreeing well with a wide range of total and regional deposition data, was used to investigate some assumptions embodied in current ICRP recommendations. Following a comparison between predictions of the new model and the original ICRP Task Group deposition model, the possible influence upon dosimetric calculations caused by various different effects were investigated. Some significant differences between regional deposition predictions of the new model and the current ICRP recommendations embodied in Publication 30 were found, up to a factor of approx 4 in some cases. The impact of improved modelling, aerosol polydispersity, the possibility of mouth as compared to nose breathing and exercise level (especially if there is transition from nose to mouth breathing at high work rates) were observed to be the most important. The impact of different breathing patterns was found to be less significant while the effect of different particle densities could be relatively successfully accounted for via a suitable transition from geometric to aerodynamic diameter. (author).

  11. Photosynthesis-related quantities for education and modeling.

    Science.gov (United States)

    Antal, Taras K; Kovalenko, Ilya B; Rubin, Andrew B; Tyystjärvi, Esa

    2013-11-01

    A quantitative understanding of the photosynthetic machinery depends largely on quantities, such as concentrations, sizes, absorption wavelengths, redox potentials, and rate constants. The present contribution is a collection of numbers and quantities related mainly to photosynthesis in higher plants. All numbers are taken directly from a literature or database source and the corresponding reference is provided. The numerical values, presented in this paper, provide ranges of values, obtained in specific experiments for specific organisms. However, the presented numbers can be useful for understanding the principles of structure and function of photosynthetic machinery and for guidance of future research.

  12. TG-43 U1 based dosimetric characterization of model 67-6520 Cs-137 brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Meigooni, Ali S.; Wright, Clarissa; Koona, Rafiq A.; Awan, Shahid B.; Granero, Domingo; Perez-Calatayud, Jose; Ballester, Facundo [Department of Radiation Medicine, North Shore University Hospital, 300 Community Drive, Manhasset, New York 11030 and Department of Radiation Medicine, University of Kentucky Chandler Medical Center, Lexington, Kentucky 40536-0084 (United States); Department of Radiation Medicine, University of Kentucky Chandler Medical Center, Lexington, Kentucky 40536-0084 (United States); Department of Radiation Physics, ERESA, Hospital General Universitario, Avenida Tres Cruces, 2, E-46014 Valencia (Spain); Department of Oncology, Physics Section, ' ' La Fe' ' University Hospital, Avenida Campanar 21, E-46009 Valencia (Spain); Department of Atomic, Molecular and Nuclear Physics, University of Valencia, C/ Dr. Moliner 50, E-46100 Burjassot, Spain and Instituto de Fisica Corpuscular (IFIC), C/ Dr. Moliner 50, E-46100 Burjassot (Spain)

    2009-10-15

    Purpose: Brachytherapy treatment has been a cornerstone for management of various cancer sites, particularly for the treatment of gynecological malignancies. In low dose rate brachytherapy treatments, {sup 137}Cs sources have been used for several decades. A new {sup 137}Cs source design has been introduced (model 67-6520, source B3-561) by Isotope Products Laboratories (IPL) for clinical application. The goal of the present work is to implement the TG-43 U1 protocol in the characterization of the aforementioned {sup 137}Cs source. Methods: The dosimetric characteristics of the IPL {sup 137}Cs source are measured using LiF thermoluminescent dosimeters in a Solid Water phantom material and calculated using Monte Carlo simulations with the GEANT4 code in Solid Water and liquid water. The dose rate constant, radial dose function, and two-dimensional anisotropy function of this source model were obtained following the TG-43 U1 recommendations. In addition, the primary and scatter dose separation (PSS) formalism that could be used in convolution/superposition methods to calculate dose distributions around brachytherapy sources in heterogeneous media was studied. Results: The measured and calculated dose rate constants of the IPL {sup 137}Cs source in Solid Water were found to be 0.930({+-}7.3%) and 0.928({+-}2.6%) cGy h{sup -1} U{sup -1}, respectively. The agreement between these two methods was within our experimental uncertainties. The Monte Carlo calculated value in liquid water of the dose rate constant was {Lambda}=0.948({+-}2.6%) cGy h{sup -1} U{sup -1}. Similarly, the agreement between measured and calculated radial dose functions and the anisotropy functions was found to be within {+-}5%. In addition, the tabulated data that are required to characterize the source using the PSS formalism were derived. Conclusions: In this article the complete dosimetry of the newly designed {sup 137}Cs IPL source following the AAPM TG-43 U1 dosimetric protocol and the PSS

  13. Biokinetic and dosimetric modelling in the estimation of radiation risks from internal emitters.

    Science.gov (United States)

    Harrison, John

    2009-06-01

    The International Commission on Radiological Protection (ICRP) has developed biokinetic and dosimetric models that enable the calculation of organ and tissue doses for a wide range of radionuclides. These are used to calculate equivalent and effective dose coefficients (dose in Sv Bq(-1) intake), considering occupational and environmental exposures. Dose coefficients have also been given for a range of radiopharmaceuticals used in diagnostic medicine. Using equivalent and effective dose, exposures from external sources and from different radionuclides can be summed for comparison with dose limits, constraints and reference levels that relate to risks from whole-body radiation exposure. Risk estimates are derived largely from follow-up studies of the survivors of the atomic bombings at Hiroshima and Nagasaki in 1945. New dose coefficients will be required following the publication in 2007 of new ICRP recommendations. ICRP biokinetic and dosimetric models are subject to continuing review and improvement, although it is arguable that the degree of sophistication of some of the most recent models is greater than required for the calculation of effective dose to a reference person for the purposes of regulatory control. However, the models are also used in the calculation of best estimates of doses and risks to individuals, in epidemiological studies and to determine probability of cancer causation. Models are then adjusted to best fit the characteristics of the individuals and population under consideration. For example, doses resulting from massive discharges of strontium-90 and other radionuclides to the Techa River from the Russian Mayak plutonium plant in the early years of its operation are being estimated using models adapted to take account of measurements on local residents and other population-specific data. Best estimates of doses to haemopoietic bone marrow, in utero and postnatally, are being used in epidemiological studies of radiation-induced leukaemia

  14. Reliability of Current Biokinetic and Dosimetric Models for Radionuclides: A Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, Richard Wayne [ORNL; Eckerman, Keith F [ORNL; Meck, Robert A. [U.S. Nuclear Regulatory Commission

    2008-10-01

    This report describes the results of a pilot study of the reliability of the biokinetic and dosimetric models currently used by the U.S. Nuclear Regulatory Commission (NRC) as predictors of dose per unit internal or external exposure to radionuclides. The study examines the feasibility of critically evaluating the accuracy of these models for a comprehensive set of radionuclides of concern to the NRC. Each critical evaluation would include: identification of discrepancies between the models and current databases; characterization of uncertainties in model predictions of dose per unit intake or unit external exposure; characterization of variability in dose per unit intake or unit external exposure; and evaluation of prospects for development of more accurate models. Uncertainty refers here to the level of knowledge of a central value for a population, and variability refers to quantitative differences between different members of a population. This pilot study provides a critical assessment of models for selected radionuclides representing different levels of knowledge of dose per unit exposure. The main conclusions of this study are as follows: (1) To optimize the use of available NRC resources, the full study should focus on radionuclides most frequently encountered in the workplace or environment. A list of 50 radionuclides is proposed. (2) The reliability of a dose coefficient for inhalation or ingestion of a radionuclide (i.e., an estimate of dose per unit intake) may depend strongly on the specific application. Multiple characterizations of the uncertainty in a dose coefficient for inhalation or ingestion of a radionuclide may be needed for different forms of the radionuclide and different levels of information of that form available to the dose analyst. (3) A meaningful characterization of variability in dose per unit intake of a radionuclide requires detailed information on the biokinetics of the radionuclide and hence is not feasible for many infrequently

  15. Forecasting Model of Coal Requirement Quantity Based on Grey System Theory

    Institute of Scientific and Technical Information of China (English)

    孙继湖

    2001-01-01

    The generally used methods of forecasting coal requirement quantity include the analogy method, the outside-push method and the cause-effect analysis method. However, the precision of forecasting results using these methods is lower. This paper uses the grey system theory, and sets up grey forecasting model GM (1, 3) to coal requirement quantity. The forecasting result for the Chinese coal requirement quantity coincides with the actual values, and this shows that the model is reliable. Finally, this model are used to forecast Chinese coal requirement quantity in the future ten years.

  16. Modeling of Groundwater Quantity and Quality Management, Nile Valley, Egypt

    Science.gov (United States)

    Owlia, R.; Fogg, G. E.

    2012-12-01

    Groundwater levels have been rising in the Luxor area of Egypt due to increased agricultural irrigation following the construction of the Aswan High Dam (AHD) in 1970. This has led to soil and groundwater salinity problems caused by increasing evapotranspiration from shallower water table, as well as the degradation of historical monuments whose foundations are weakening by capillary rise of water into the columns and stonework. While similar salinity problems exist elsewhere in the world (e.g., San Joaquin Valley of California), we hypothesize that as long as groundwater discharge to the Nile River continues and serves as a sink for the salt, the regional salt balance will be manageable and will not lead to irreversible salinization of soils. Further, we hypothesize that if a groundwater system such as this one becomes overdrafted, thereby cutting off groundwater discharge to the River, the system salt balance will be less manageable and possibly non-sustainable. With groundwater flow modeling we are investigating approaches for managing the irrigation and groundwater levels so as to eliminate water stresses on Egyptian monuments and antiquities. Consequences of possible actions for managing the water table through groundwater pumping and alternative irrigation practices will be presented. Moreover, through the use of high resolution modeling of system heterogeneity, we will simulate the long term salt balance of the system under various scenarios, including the overdraft case. The salt source will be a function of groundwater discharge to the surface via bare-soil evaporation and crop transpiration. The built-in heterogeneity will account for dispersion, fast transport in connected media and slow mass transfer between aquifer and aquitard materials. Key Words: Groundwater, modeling, water quality, sustainability, salinity, irrigated agriculture, Nile aquifer.

  17. Determination of Dosimetric Parameters of the Second Model of Pd-103 Seed Manufactured at Agricultural, Medical and Industrial Research School

    Directory of Open Access Journals (Sweden)

    Gholamreza Raisali

    2008-06-01

    Full Text Available Introduction: The use of low energy isotopes such as  103 Pd in brachytherapy for the treatment of cancers  such as prostate, eye, head, neck, breast and cervix is increasing. In this regard, different models of Pd- 103  seeds  have  been  designed  and  manufactured  at  the  Agricultural,  Medical  and  Industrial  Research  School (AMIRS of Atomic Energy Organization of Iran. In this research, the dosimetric parameters of  the second model of Pd-103 seed manufactured at AMIRS have been calculated and measured.   Materials and Methods: The dosimetric parameters of the second Pd-103 seed manufactured at AMIRS  were determined according to TG-43U1 protocol using Monte Carlo calculations (MCNP4C computer  code  and  measurements  performed  using  TLD-GR200A  dosimeters  in  a  Perspex  phantom.  The  parameters  include  dose  rate  constant,  geometry  function,  radial  dose  function,  anisotropy  function,  anisotropy factor and anisotropy constant.  Results:  It  was  found  that  by  using  MCNP4C  code  the  calculated  dose  rate  constant  in  water  and  Perspex  was  0.706±0.001   and  0.501±0.001  cGyh -1 U -1 , respectively.  Using  the  calculated  geometry  function,  the  radial  dose  function  and  the  anisotropy  function  were  determined  by  experimental  and  theoretical methods in water and Perspex phantom. Also, the calculated value of anisotropy constant in  water was equal to 0.88.  Discussion and Conclusion: A discrepancy of less than 10% between the calculated and the measured  values indicates a reasonable agreement between the simulation and the measurement method. Also, the  dosimetric parameters of this seed have been compared to the dosimetric parameters of the first Pd-103  seed  manufactured  at  AMIRS  and  some  other  seeds.  The  obtained  results  indicate  that  the  seeds  manufactured at AMIRS

  18. A radioactive seed implant on a rabbit's liver following a voxel model representation for dosimetric proposals

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Tarcisio P.R.; Andrade, Joao Paulo Lopes de; Costa, Igor Temponi; Teixeira, Cleuza H. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares]. E-mail: campos@nuclear.ufmg

    2005-07-01

    Animal models have been used in experimentation with ionizing radiation. The evaluation of the energy absorbed per unit tissue mass in vivo transported by nuclear particles is a task to be performed before experimentation. Stochastic or deterministic methodology can be applied, however the dosimetric protocols applied in radiotherapy center cannot be applied directly due to the inherent small geometry and chemical composition of the animal distinct from human. The present article addresses a method in development that will predict the dose distribution into the rabbit thorax based on the solution of the transport phenomena in a voxel model. The model will be applied to simulate a seed implant experiment on a rabbit. Herein, the construction of the three-dimensional voxel model anthropomorphic -anthropometrics to the rabbit is presented. The model is assembling from a set of computer tomography of the rabbit. The computational phantom of the thorax starts at the digitalisation of the CT images, tissue definition, and color image representation of each tissue and organ. The chemical composition and mass density of each tissue is evaluated as similar date presented by ICRU-44. To treat the images, a code namely SISCODES, developed in house, was used. The in vivo experiment that will be simulated is also described. That is a implant of five seeds of 1.6x2 mm performed in a rabbit's liver. The perspective of this work is the application of the model in dosimetric studies predicting the dose distribution around the seed's implanted in vivo experiments. (author)

  19. Automated Decisional Model for Optimum Economic Order Quantity Determination Using Price Regressive Rates

    Science.gov (United States)

    Roşu, M. M.; Tarbă, C. I.; Neagu, C.

    2016-11-01

    The current models for inventory management are complementary, but together they offer a large pallet of elements for solving complex problems of companies when wanting to establish the optimum economic order quantity for unfinished products, row of materials, goods etc. The main objective of this paper is to elaborate an automated decisional model for the calculus of the economic order quantity taking into account the price regressive rates for the total order quantity. This model has two main objectives: first, to determine the periodicity when to be done the order n or the quantity order q; second, to determine the levels of stock: lighting control, security stock etc. In this way we can provide the answer to two fundamental questions: How much must be ordered? When to Order? In the current practice, the business relationships with its suppliers are based on regressive rates for price. This means that suppliers may grant discounts, from a certain level of quantities ordered. Thus, the unit price of the products is a variable which depends on the order size. So, the most important element for choosing the optimum for the economic order quantity is the total cost for ordering and this cost depends on the following elements: the medium price per units, the stock cost, the ordering cost etc.

  20. Economic Order Quantity Model with Two Levels of Delayed Payment and Bad Debt

    Directory of Open Access Journals (Sweden)

    Qin Juanjuan

    2012-08-01

    Full Text Available The purpose of this study is to determine the optimal retailer’s replenishment policies considering the customers’ bad debt and delayed payment in the three-stage supply chain with the dominant retailer. The effect of bad debt is analyzed on the interest earned and interest charged to build the models of the retailer’s decision in two cases. By analyzing the model, the retailer’s optimal replenishment time and the optimal order quantity are obtained. Furthermore, analyze the effect of parameters on the retailer’s optimal order policies. Finally, the numerical analysis is presented to demonstrate the conclusions. The results show that the delayed payment offered by the manufacturer becomes large, the retailer's optimal order cycle and the optimal order quantity increases or remains the same; When the delayed payment time offered by the retailer decreases, the retailer's optimal order cycle and the optimal order quantity increases or remains the same. When the fixed ordering cost is reduced, the retailer's optimal order cycle and the optimal order quantity decreases or remains the same. When the charged interest is greater than the earned interest, with the bad debt rate increasing, the retailer's optimal order cycle and optimal order quantity is converged to a certain value.

  1. Economic Modelling for water Quantity and Quality Management: A Welfare Program Approach

    NARCIS (Netherlands)

    Zhu, X.; Ierland, van E.C.

    2012-01-01

    This paper presents an integrated economic model which is able to explicitly address both water quantity and quality. We use a welfare program to maximize social welfare subject to the economic and ecological constraints, where interactions, emissions and environmental impacts are incorporated. Such

  2. Application of the Physical Quantity Field Evolution under Numerical Model in Precipitation Forecast of Yantai

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective]The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai during 2-3 July and 12-15 September,2011,advantages and disadvantages of the different numerical forecast models (Japan fax chart,European center,MM5,Grapes and T639) were analyzed.[Result] MICAPS system could provide live situation of the physical quantity field,but couldn't provide the future evolu...

  3. Estimates of critical quantities from an expansion in mass: Ising model on the simple cubic lattice

    CERN Document Server

    Yamada, Hirofumi

    2015-01-01

    In Ising model on the simple cubic lattice, we describe the inverse temperature $\\beta$ and other quantities relevant for the computation of critical quantities in terms of a dimensionless squared mass $M$. The critical behaviors of those quantities are represented by the linear differential equations with constant coefficients which are related to critical exponents. We estimate the critical temperature and exponents via an expansion in the inverse powers of the mass under the use of $\\delta$-expansion. The critical inverse temperature $\\beta_{c}$ is estimated first in unbiased manner and then critical exponents are also estimated in biased and unbiased self-contained way including $\\omega$, the correction-to-scaling exponent, $\

  4. Multi products single machine economic production quantity model with multiple batch size

    Directory of Open Access Journals (Sweden)

    Ata Allah Taleizadeh

    2011-04-01

    Full Text Available In this paper, a multi products single machine economic order quantity model with discrete delivery is developed. A unique cycle length is considered for all produced items with an assumption that all products are manufactured on a single machine with a limited capacity. The proposed model considers different items such as production, setup, holding, and transportation costs. The resulted model is formulated as a mixed integer nonlinear programming model. Harmony search algorithm, extended cutting plane and particle swarm optimization methods are used to solve the proposed model. Two numerical examples are used to analyze and to evaluate the performance of the proposed model.

  5. Modified economic order quantity (EOQ model for items with imperfect quality: Game-theoretical approaches

    Directory of Open Access Journals (Sweden)

    Milad Elyasi

    2014-04-01

    Full Text Available In the recent decade, studying the economic order quantity (EOQ models with imperfect quality has appealed to many researchers. Only few papers are published discussing EOQ models with imperfect items in a supply chain. In this paper, a two-echelon decentralized supply chain consisting of a manufacture and a supplier that both face just in time (JIT inventory problem is considered. It is sought to find the optimal number of the shipments and the quantity of each shipment in a way that minimizes the both manufacturer’s and the supplier’s cost functions. To the authors’ best knowledge, this is the first paper that deals with imperfect items in a decentralized supply chain. Thereby, three different game theoretical solution approaches consisting of two non-cooperative games and a cooperative game are proposed. Comparing the results of three different scenarios with those of the centralized model, the conclusions are drawn to obtain the best approach.

  6. Improving efficiencies in pharmaceutical distribution channels using the economic order quantity model.

    Science.gov (United States)

    Sullivan, D L; Schommer, J C

    1993-01-01

    The purpose of this study was to investigate empirically the potential cost savings to a pharmaceutical wholesaler using the Economic Order Quantity (EOQ) model. This model allows for calculating the order quantity that minimizes both ordering and holding costs. A regional pharmaceutical wholesaler was selected for a case analysis study using the EOQ model. Eleven brand name products were randomly selected for the analysis. The average yearly cost savings using EOQ was $31.92 per product. The potential yearly cost savings based on 8500 brand name stock-keeping units was $271,320. Using EOQ can therefore assist pharmaceutical wholesalers in minimizing holding and ordering costs and improve efficiency for pharmaceutical distribution channels.

  7. Determination of Economic Order Quantity in a fuzzy EOQ Model using of GMIR Deffuzification

    Directory of Open Access Journals (Sweden)

    Hamidreza Salmani Mojaveri

    2017-03-01

    Full Text Available Inappropriate inventory control policies and its incorrect implementation can cause improper operation and uncompetitive advantage of organization logistic operation in the market. Therefore, analysis inventory control policies are important to be understood, including carrying cost, ordering cost, warehouse renting cost, and buying cost. In this research, Economic Order Quantity (EOQ problem in fuzzy condition is reviewed in two different situations. The first model concerned to costs (carrying cost, ordering cost, warehouse renting cost and buying cost, which is considered as triangular fuzzy numbers. The second model was in addition to inventory the cost system, in which annual demand is also reviewed as fuzzy numbers. In each model, graded mean integration representation (GMIR deffuzification was used for parameters deffuzification. Then, the final objective from this analysis was to obtain economic quantity formula through derivation.

  8. Economic production quantity models for imperfect product and service with rework

    OpenAIRE

    Tai, Allen H.

    2012-01-01

    When imperfect quality products are produced in a production process, rework may be performed to make them become serviceable. In an inventory system, items may deteriorate. Selling deteriorated items to customers will create negative impact on corporate image. In this paper, two economic production quantity (EPQ) models are proposed for deteriorating items with rework process. A single production-rework plant system and a system consists of $n$ production plants and one rework plant are cons...

  9. Applying nonlinear MODM model to supply chain management with quantity discount policy under complex fuzzy environment

    Directory of Open Access Journals (Sweden)

    Zhe Zhang

    2014-06-01

    Full Text Available Purpose: The aim of this paper is to deal with the supply chain management (SCM with quantity discount policy under the complex fuzzy environment, which is characterized as the bi-fuzzy variables. By taking into account the strategy and the process of decision making, a bi-fuzzy nonlinear multiple objective decision making (MODM model is presented to solve the proposed problem.Design/methodology/approach: The bi-fuzzy variables in the MODM model are transformed into the trapezoidal fuzzy variables by the DMs's degree of optimism ?1 and ?2, which are de-fuzzified by the expected value index subsequently. For solving the complex nonlinear model, a multi-objective adaptive particle swarm optimization algorithm (MO-APSO is designed as the solution method.Findings: The proposed model and algorithm are applied to a typical example of SCM problem to illustrate the effectiveness. Based on the sensitivity analysis of the results, the bi-fuzzy nonlinear MODM SCM model is proved to be sensitive to the possibility level ?1.Practical implications: The study focuses on the SCM under complex fuzzy environment in SCM, which has a great practical significance. Therefore, the bi-fuzzy MODM model and MO-APSO can be further applied in SCM problem with quantity discount policy.Originality/value: The bi-fuzzy variable is employed in the nonlinear MODM model of SCM to characterize the hybrid uncertain environment, and this work is original. In addition, the hybrid crisp approach is proposed to transferred to model to an equivalent crisp one by the DMs's degree of optimism and the expected value index. Since the MODM model consider the bi-fuzzy environment and quantity discount policy, so this paper has a great practical significance.

  10. Diversity not quantity in caregiver speech: Using computational modeling to isolate the effects of the quantity and the diversity of the input on vocabulary growth.

    Science.gov (United States)

    Jones, Gary; Rowland, Caroline F

    2017-11-01

    Children who hear large amounts of diverse speech learn language more quickly than children who do not. However, high correlations between the amount and the diversity of the input in speech samples makes it difficult to isolate the influence of each. We overcame this problem by controlling the input to a computational model so that amount of exposure to linguistic input (quantity) and the quality of that input (lexical diversity) were independently manipulated. Sublexical, lexical, and multi-word knowledge were charted across development (Study 1), showing that while input quantity may be important early in learning, lexical diversity is ultimately more crucial, a prediction confirmed against children's data (Study 2). The model trained on a lexically diverse input also performed better on nonword repetition and sentence recall tests (Study 3) and was quicker to learn new words over time (Study 4). A language input that is rich in lexical diversity outperforms equivalent richness in quantity for learned sublexical and lexical knowledge, for well-established language tests, and for acquiring words that have never been encountered before. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Forecasting of municipal solid waste quantity in a developing country using multivariate grey models

    Energy Technology Data Exchange (ETDEWEB)

    Intharathirat, Rotchana, E-mail: rotchana.in@gmail.com [Energy Field of Study, School of Environment, Resources and Development, Asian Institute of Technology, P.O. Box 4, KlongLuang, Pathumthani 12120 (Thailand); Abdul Salam, P., E-mail: salam@ait.ac.th [Energy Field of Study, School of Environment, Resources and Development, Asian Institute of Technology, P.O. Box 4, KlongLuang, Pathumthani 12120 (Thailand); Kumar, S., E-mail: kumar@ait.ac.th [Energy Field of Study, School of Environment, Resources and Development, Asian Institute of Technology, P.O. Box 4, KlongLuang, Pathumthani 12120 (Thailand); Untong, Akarapong, E-mail: akarapong_un@hotmail.com [School of Tourism Development, Maejo University, Chiangmai (Thailand)

    2015-05-15

    Highlights: • Grey model can be used to forecast MSW quantity accurately with the limited data. • Prediction interval overcomes the uncertainty of MSW forecast effectively. • A multivariate model gives accuracy associated with factors affecting MSW quantity. • Population, urbanization, employment and household size play role for MSW quantity. - Abstract: In order to plan, manage and use municipal solid waste (MSW) in a sustainable way, accurate forecasting of MSW generation and composition plays a key role. It is difficult to carry out the reliable estimates using the existing models due to the limited data available in the developing countries. This study aims to forecast MSW collected in Thailand with prediction interval in long term period by using the optimized multivariate grey model which is the mathematical approach. For multivariate models, the representative factors of residential and commercial sectors affecting waste collected are identified, classified and quantified based on statistics and mathematics of grey system theory. Results show that GMC (1, 5), the grey model with convolution integral, is the most accurate with the least error of 1.16% MAPE. MSW collected would increase 1.40% per year from 43,435–44,994 tonnes per day in 2013 to 55,177–56,735 tonnes per day in 2030. This model also illustrates that population density is the most important factor affecting MSW collected, followed by urbanization, proportion employment and household size, respectively. These mean that the representative factors of commercial sector may affect more MSW collected than that of residential sector. Results can help decision makers to develop the measures and policies of waste management in long term period.

  12. The Effect of Units Lost Due to Deterioration in Fuzzy Economic Order Quantity (FEOQ Model

    Directory of Open Access Journals (Sweden)

    M. Pattnaik

    2013-07-01

    Full Text Available For several decades, the Economic Order Quantity (EOQ model and its variations have received much attention from researchers. Recently, there has been an investigation into an EOQ model incorporating effect of units lost due to deterioration in infinite planning horizon with crisp decision environment. Accounting for holding and ordering cost, as has traditionally been the case of modeling inventory systems in fuzzy environment are investigated which are not precisely known and defined on a bounded interval of real numbers. The question is how reliable are the EOQ models when items stocked deteriorate one time. This paper introduces Fuzzy Economic Order Quantity (FEOQ model in which it assumes that units lost due to deterioration is included in the objective function to properly model the problem in finite planning horizon. The numerical analysis shows that an appropriate fuzzy policy can benefit the retailer and that is significant, especially for deteriorating items is shown to be superior to that of crisp decision making. A computational algorithm using LINGO 13.0 and MATLAB (R2009a software are developed to find the optimal solution. Sensitivity analysis of the optimal solution is also studied and managerial insights are drawn which shows the influence of key model parameters.

  13. Estimation of Several Turbulent Fluctuation Quantities Using an Approximate Pulsatile Flow Model

    Energy Technology Data Exchange (ETDEWEB)

    Dechant, Lawrence J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    Turbulent fluctuation behavior is approximately modeled using a pulsatile flow model analogy.. This model follows as an extension to the turbulent laminar sublayer model developed by Sternberg (1962) to be valid for a fully turbulent flow domain. Here unsteady turbulent behavior is modeled via a sinusoidal pulsatile approach. While the individual modes of the turbulent flow fluctuation behavior are rather crudely modeled, approximate temporal integration yields plausible estimates for Root Mean Square (RMS) velocity fluctuations. RMS pressure fluctuations and spectra are of particular interest and are estimated via the pressure Poisson expression. Both RMS and Power Spectral Density (PSD), i.e. spectra are developed. Comparison with available measurements suggests reasonable agreement. An additional fluctuating quantity, i.e. RMS wall shear fluctuation is also estimated, yielding reasonable agreement with measurement.

  14. Economic Production Quantity (EPQ model for three type imperfect items with rework and learning in setup

    Directory of Open Access Journals (Sweden)

    Arindum Mukhopadhyay

    2014-01-01

    Full Text Available Imperfect quality Items are unavoidable in an Inventory system due to imperfect productionprocess, natural disasters, damages, or many other reasons. The setup cost and production cycletime can be related in terms of process deterioration and learning and forgetting effects. Learningreduces production run length and setup cost, whereas deterioration and forgetting increases both.Keeping these facts in mind, this paper investigates an Economic Production Quantity (EPQ modelwith imperfect quality items with varying set-up costs. Mathematical model and solution proceduresare developed with major insight to its charecteristics. Numerical example and sensitivity analysisare provided to illustrate and analyze the model performance. It is observed that our model has asignificant impacts on the optimal lot size and optimal profit of the model.

  15. Contaminant point source localization error estimates as functions of data quantity and model quality

    Science.gov (United States)

    Hansen, Scott K.; Vesselinov, Velimir V.

    2016-10-01

    We develop empirically-grounded error envelopes for localization of a point contamination release event in the saturated zone of a previously uncharacterized heterogeneous aquifer into which a number of plume-intercepting wells have been drilled. We assume that flow direction in the aquifer is known exactly and velocity is known to within a factor of two of our best guess from well observations prior to source identification. Other aquifer and source parameters must be estimated by interpretation of well breakthrough data via the advection-dispersion equation. We employ high performance computing to generate numerous random realizations of aquifer parameters and well locations, simulate well breakthrough data, and then employ unsupervised machine optimization techniques to estimate the most likely spatial (or space-time) location of the source. Tabulating the accuracy of these estimates from the multiple realizations, we relate the size of 90% and 95% confidence envelopes to the data quantity (number of wells) and model quality (fidelity of ADE interpretation model to actual concentrations in a heterogeneous aquifer with channelized flow). We find that for purely spatial localization of the contaminant source, increased data quantities can make up for reduced model quality. For space-time localization, we find similar qualitative behavior, but significantly degraded spatial localization reliability and less improvement from extra data collection. Since the space-time source localization problem is much more challenging, we also tried a multiple-initial-guess optimization strategy. This greatly enhanced performance, but gains from additional data collection remained limited.

  16. Pengembangan Model Economic Production Quantity (EPQ dengan Sinkronisasi Demand Kontinu dan Diskrit Secara Simultan

    Directory of Open Access Journals (Sweden)

    Nurike Oktavia

    2016-04-01

    Full Text Available The most popular inventory model to determine production lot size is Economic Production Quantity (EPQ. It shows enterprise how to minimize total production cost by reducing inventory cost. But, three main parameters in EPQ which are demand, machine set up cost, and holding cost, are not suitable to solve issues nowadays. When enterprise has two types of demand, continue and discrete demand, the basic EPQ would be no longer useful. Demand continue comes from customer who wants their needs to be fullfilled everytime per unit time, while fullfillment of demand descrete is at a fixed interval of time. Literature review is done by writers to observe other formulation of EPQ model. As there is no other research can be found which adopt this topic, this study try to develop EPQ model considering two types of demand simoultaneously.

  17. Simultaneous modelling of multi-purpose/multi-stop activity patterns and quantities consumed

    Science.gov (United States)

    Roy, John R.; Smith, Nariida C.; Xu, Blake

    Whereas for commuting travel there is a one-to-one correspondence between commuters and jobs, and for commodity flows a one-to-one correspondence between the size of orders and the shipping cost of the commodities, the situation is much more complex for retail/service travel. A typical shopper may make a single trip or multi-stop tour to buy/consume a quite diverse set of commodities/services at different locations in quite variable quantities. At the same time, the general pattern of the tour is clearly dependent on the activities and goods available at potential stops. These interdependencies have been alluded to in the literature, especially by spatial economists. However, until some preliminary work by the first author, there has been no attempt to formally include these interdependencies in a general model. This paper presents a framework for achieving this goal by developing an evolutionary set of models starting from the simplest forms available. From the above, it is clear that such interdependency models will inevitably have high dimensionality and combinatorial complexity. This rules out a simultaneous treatment of all the events using an individual choice approach. If an individual choice approach is to be applied in a tractable manner, the set of interdependent events needs to be segmented into several subsets, with simultaneity recognised within each subset, but a mere sequential progression occurring between subsets. In this paper, full event interdependencies are retained at the expense of modelling market segments of consumers rather than a sample of representative individuals. We couple the travel and consumption events in the only feasible way, by modelling the tours as discrete entities, in conjunction with the amount of each commodity consumed per stop on each such tour in terms of the continuous quantities of microeconomics. This is performed both under a budget/income constraint from microeconomics and a time budget constraint from time

  18. Comparison of different uncertainty techniques in urban stormwater quantity and quality modelling

    DEFF Research Database (Denmark)

    Dotto, C. B.; Mannina, G.; Kleidorfer, M.

    2012-01-01

    is the assessment and comparison of different techniques generally used in the uncertainty assessment of the parameters of water models. This paper compares a number of these techniques: the Generalized Likelihood Uncertainty Estimation (GLUE), the Shuffled Complex Evolution Metropolis algorithm (SCEM......-UA), an approach based on a multi-objective auto-calibration (a multialgorithm, genetically adaptive multiobjective method, AMALGAM) and a Bayesian approach based on a simplified Markov Chain Monte Carlo method (implemented in the software MICA). To allow a meaningful comparison among the different uncertainty...... techniques, common criteria have been set for the likelihood formulation, defining the number of simulations, and the measure of uncertainty bounds. Moreover, all the uncertainty techniques were implemented for the same case study, in which the same stormwater quantity and quality model was used alongside...

  19. Modeling the advection of discontinuous quantities in Geophysical flows using Particle Level Sets

    Science.gov (United States)

    Aleksandrov, V.; Samuel, H.; Evonuk, M.

    2010-12-01

    Advection is one of the major processes that commonly acts on various scales in nature (core formation, mantle convective stirring, multi-phase flows in magma chambers, salt diapirism ...). While this process can be modeled numerically by solving conservation equations, various geodynamic scenarios involve advection of quantities with sharp discontinuities. Unfortunately, in these cases modeling numerically pure advection becomes very challenging, in particular because sharp discontinuities lead to numerical instabilities, which prevent the local use of high order numerical schemes. Several approaches have been used in computational geodynamics in order to overcome this difficulty, with variable amounts of success. Despite the use of correcting filters or non-oscillatory, shock-preserving schemes, Eulerian (fixed grid) techniques generally suffer from artificial numerical diffusion. Lagrangian approaches (dynamic grids or particles) tend to be more popular in computational geodynamics because they are not prone to excessive numerical diffusion. However, these approaches are generally computationally expensive, especially in 3D, and can suffer from spurious statistical noise. As an alternative to these aforementioned approaches, we have applied a relatively recent Particle Level set method [Enright et al., 2002] for modeling advection of quantities with the presence of sharp discontinuities. We have tested this improved method, which combines the best of Eulerian and Lagrangian approaches, against well known benchmarks and classical Geodynamic flows. In each case the Particle Level Set method accuracy equals or is better than other Eulerian and Lagrangian methods, and leads to significantly smaller computational cost, in particular in three-dimensional flows, where the reduction of computational time for modeling advection processes is most needed.

  20. The Revised International Commission on Radiological Protection (ICRP) dosimetric model for the human respiratory tract

    Energy Technology Data Exchange (ETDEWEB)

    Bair, W.J.

    1991-09-01

    The new respiratory tract model is based on the premise that the large differences in radiation sensitivity of respiratory tract tissues, and the wide range of doses they receive, argue for calculating specific tissue doses rather than average lung doses for radiation protection purposes. The new model is more complex than the current lung model because it describes deposition of inhaled radioactive material in the clearance from several tissues and regions of the respiratory tract and is applicable to the worldwide population of both workers and the public. 2 refs., 2 figs.

  1. Pu-239 organ specific dosimetric model applied to non-human biota

    Science.gov (United States)

    Kaspar, Matthew Jason

    There are few locations throughout the world, like the Maralinga nuclear test site located in south western Australia, where sufficient plutonium contaminate concentration levels exist that they can be utilized for studies of the long-term radionuclide accumulation in non-human biota. The information obtained will be useful for the potential human users of the site while also keeping with international efforts to better understand doses to non-human biota. In particular, this study focuses primarily on a rabbit sample set collected from the population located within the site. Our approach is intended to employ the same dose and dose rate methods selected by the International Commission on Radiological Protection and adapted by the scientific community for similar research questions. These models rely on a series of simplifying assumptions on biota and their geometry; in particular; organisms are treated as spherical and ellipsoidal representations displaying the animal mass and volume. These simplifications assume homogeneity of all animal tissues. In collaborative efforts between Colorado State University and the Australian Nuclear Science and Technology Organisation (ANSTO), we are expanding current knowledge on radionuclide accumulation in specific organs causing organ-specific dose rates, such as Pu-239 accumulating in bone, liver, and lungs. Organ-specific dose models have been developed for humans; however, little has been developed for the dose assessment to biota, in particular rabbits. This study will determine if it is scientifically valid to use standard software, in particular ERICA Tool, as a means to determine organ-specific dosimetry due to Pu-239 accumulation in organs. ERICA Tool is normally applied to whole organisms as a means to determine radiological risk to whole ecosystems. We will focus on the aquatic model within ERICA Tool, as animal organs, like aquatic organisms, can be assumed to lie within an infinite uniform medium. This model would

  2. Dosimetric model for intraperitoneal targeted liposomal radioimmunotherapy of ovarian cancer micrometastases

    Energy Technology Data Exchange (ETDEWEB)

    Syme, A M [Department of Physics, University of Alberta, 412 Avadh Bhatia Physics Laboratory, Edmonton, Alberta T6G 2J1 (Canada); McQuarrie, S A [Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, 3118 Dentistry/Pharmacy Centre, Edmonton, Alberta T6G 2N8 (Canada); Middleton, J W [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Fallone, B G [Departments of Physics and Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2003-05-21

    A simple model has been developed to investigate the dosimetry of micrometastases in the peritoneal cavity during intraperitoneal targeted liposomal radioimmunotherapy. The model is applied to free-floating tumours with radii between 0.005 cm and 0.1 cm. Tumour dose is assumed to come from two sources: free liposomes in solution in the peritoneal cavity and liposomes bound to the surface of the micrometastases. It is assumed that liposomes do not penetrate beyond the surface of the tumours and that the total amount of surface antigen does not change over the course of treatment. Integrated tumour doses are expressed as a function of biological parameters that describe the rates at which liposomes bind to and unbind from the tumour surface, the rate at which liposomes escape from the peritoneal cavity and the tumour surface antigen density. Integrated doses are translated into time-dependent tumour control probabilities (TCPs). The results of the work are illustrated in the context of a therapy in which liposomes labelled with Re-188 are targeted at ovarian cancer cells that express the surface antigen CA-125. The time required to produce a TCP of 95% is used to investigate the importance of the various parameters. The relative contributions of surface-bound radioactivity and unbound radioactivity are used to assess the conditions required for a targeted approach to provide an improvement over a non-targeted approach during intraperitoneal radiation therapy. Using Re-188 as the radionuclide, the model suggests that, for microscopic tumours, the relative importance of the surface-bound radioactivity increases with tumour size. This is evidenced by the requirement for larger antigen densities on smaller tumours to affect an improvement in the time required to produce a TCP of 95%. This is because for the smallest tumours considered, the unbound radioactivity is often capable of exerting a tumouricidal effect before the targeting agent has time to accumulate

  3. Optimization in Fuzzy Economic Order Quantity (FEOQ Model with Deteriorating Inventory and Units Lost

    Directory of Open Access Journals (Sweden)

    Monalisha Pattnaik

    2014-09-01

    Full Text Available Background: This model presents the effect of deteriorating items in fuzzy optimal instantaneous replenishment for finite planning horizon. Accounting for holding cost per unit per unit time and ordering cost per order have traditionally been the case of modeling inventory systems in fuzzy environment. These imprecise parameters defined on a bounded interval on the axis of real numbers and the physical characteristics of stocked items dictate the nature of inventory policies implemented to manage and control in the production system.   Methods: The modified fuzzy EOQ (FEOQ model is introduced, it assumes that a percentage of the on-hand inventory is wasted due to deterioration and considered as an enhancement to EOQ model to determine the optimal replenishment quantity so that the net profit is maximized. In theoretical analysis, the necessary and sufficient conditions of the existence and uniqueness of the optimal solutions are proved and further the concavity of the fuzzy net profit function is established. Computational algorithm using the software LINGO 13.0 version is developed to find the optimal solution.   Results and conclusions: The results of the numerical analysis enable decision-makers to quantify the effect of units lost due to deterioration on optimizing the fuzzy net profit for the retailer. Finally, sensitivity analyses of the optimal solution with respect the major parameters are also carried out. Furthermore fuzzy decision making is shown to be superior then crisp decision making in terms of profit maximization. 

  4. Freshwater DOM quantity and quality from a two-component model of UV absorbance

    Science.gov (United States)

    Carter, Heather T.; Tipping, Edward; Koprivnjak, Jean-Francois; Miller, Matthew P.; Cookson, Brenda; Hamilton-Taylor, John

    2012-01-01

    We present a model that considers UV-absorbing dissolved organic matter (DOM) to consist of two components (A and B), each with a distinct and constant spectrum. Component A absorbs UV light strongly, and is therefore presumed to possess aromatic chromophores and hydrophobic character, whereas B absorbs weakly and can be assumed hydrophilic. We parameterised the model with dissolved organic carbon concentrations [DOC] and corresponding UV spectra for c. 1700 filtered surface water samples from North America and the United Kingdom, by optimising extinction coefficients for A and B, together with a small constant concentration of non-absorbing DOM (0.80 mg DOC L-1). Good unbiased predictions of [DOC] from absorbance data at 270 and 350 nm were obtained (r2 = 0.98), the sum of squared residuals in [DOC] being reduced by 66% compared to a regression model fitted to absorbance at 270 nm alone. The parameterised model can use measured optical absorbance values at any pair of suitable wavelengths to calculate both [DOC] and the relative amounts of A and B in a water sample, i.e. measures of quantity and quality. Blind prediction of [DOC] was satisfactory for 9 of 11 independent data sets (181 of 213 individual samples).

  5. Thermoluminescence system CaF sub 2 Tm models, dosimetric properties and applications

    CERN Document Server

    Summerer, L M

    2002-01-01

    In parallel with the increasing level of exposure to ionizing radiation in modern society, dosimeters to measure absorbed doses were developed and studied. One of the most widespread systems are thermoluminescence crystals. The history of thermoluminescence dosimetry is a history of success. Since decades, hundreds of publications appear every year on the large topic of thermoluminescence dosimetry. A majority of them deals with LiF:Mg,Ti, the by far most widely used and studied thermoluminescent crystal. In this work, we are going to analyze in detail the properties of a different thermoluminescence dosimetry system, CaF sub 2 :Tm, rarely used and scarcely described. Most of the theoretical models explaining the physical processes involved in thermoluminescence are based on LiF:Mg,Ti crystals. The major models are reviewed and their applicability to CaF sub 2 :Tm is examined. On the basis of results, obtained with the spectral analysis of the TL light after irradiation with different heavy ions, a new theore...

  6. Comparison of different uncertainty techniques in urban stormwater quantity and quality modelling.

    Science.gov (United States)

    Dotto, Cintia B S; Mannina, Giorgio; Kleidorfer, Manfred; Vezzaro, Luca; Henrichs, Malte; McCarthy, David T; Freni, Gabriele; Rauch, Wolfgang; Deletic, Ana

    2012-05-15

    Urban drainage models are important tools used by both practitioners and scientists in the field of stormwater management. These models are often conceptual and usually require calibration using local datasets. The quantification of the uncertainty associated with the models is a must, although it is rarely practiced. The International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, has been working on the development of a framework for defining and assessing uncertainties in the field of urban drainage modelling. A part of that work is the assessment and comparison of different techniques generally used in the uncertainty assessment of the parameters of water models. This paper compares a number of these techniques: the Generalized Likelihood Uncertainty Estimation (GLUE), the Shuffled Complex Evolution Metropolis algorithm (SCEM-UA), an approach based on a multi-objective auto-calibration (a multialgorithm, genetically adaptive multi-objective method, AMALGAM) and a Bayesian approach based on a simplified Markov Chain Monte Carlo method (implemented in the software MICA). To allow a meaningful comparison among the different uncertainty techniques, common criteria have been set for the likelihood formulation, defining the number of simulations, and the measure of uncertainty bounds. Moreover, all the uncertainty techniques were implemented for the same case study, in which the same stormwater quantity and quality model was used alongside the same dataset. The comparison results for a well-posed rainfall/runoff model showed that the four methods provide similar probability distributions of model parameters, and model prediction intervals. For ill-posed water quality model the differences between the results were much wider; and the paper provides the specific advantages and disadvantages of each method. In relation to computational efficiency (i.e. number of iterations required to generate the probability

  7. Impact of data quality and quantity and the calibration procedure on crop growth model calibration

    Science.gov (United States)

    Seidel, Sabine J.; Werisch, Stefan

    2014-05-01

    Crop growth models are a commonly used tool for impact assessment of climate variability and climate change on crop yields and water use. Process-based crop models rely on algorithms that approximate the main physiological plant processes by a set of equations containing several calibration parameters as well as basic underlying assumptions. It is well recognized that model calibration is essential to improve the accuracy and reliability of model predictions. However, model calibration and validation is often hindered by a limited quantity and quality of available data. Recent studies suggest that crop model parameters can only be derived from field experiments in which plant growth and development processes have been measured. To be able to achieve a reliable prediction of crop growth under irrigation or drought stress, the correct characterization of the whole soil-plant-atmosphere system is essential. In this context is the accurate simulation of crop development, yield and the soil water dynamics plays an important role. In this study we aim to investigate the importance of a site and cultivar-specific model calibration based on experimental data using the SVAT model Daisy. We investigate to which extent different data sets and different parameter estimation procedures affect particularly yield estimates, irrigation water demand and the soil water dynamics. The comprehensive experimental data has been derived from an experiment conducted in Germany where five irrigation regimes were imposed on cabbage. Data collection included continuous measurements of soil tension and soil water content in two plots at three depths, weekly measurements of LAI, plant heights, leaf-N-content, stomatal conductivity, biomass partitioning, rooting depth as well as harvested yields and duration of growing period. Three crop growth calibration strategies were compared: (1) manual calibration based on yield and duration of growing period, (2) manual calibration based on yield

  8. Model for Bidding and Tendering with Bill of Quantities Based on Bid-Winning Estimate at Reasonable Low Price

    Institute of Scientific and Technical Information of China (English)

    Song Jirong; Zhong Sheng; Guo Yaohuang

    2006-01-01

    The possibility and rationality of introducing an bid-winning estimate based on a reasonable low price into construction bidding mode with bill of quantities were analyzed by setting up a model for bidding and tendering, and the functions of the estimate of reasonable low price in the bidding were revealed. On this basis, a new bidding mode of the project with bill of quantities was proposed. The application of the new mode will be advantageous to the promotion of the bill of quantities in China.

  9. MODEL OF CALCULATING WATER QUANTITY NEEDED TO DILUTE AND PURIFY POLLUTANTS IN RIVER NETWORK AND ITS APPLICATIONS

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; WANG Pei-fang

    2005-01-01

    Based on the analysis of dilution capacity and self-purification capacity of water body, the dilution, dispersion, entrapping and purification principles of pollutants in river system at river network area were discussed in this paper. Also, the one and two dimensional models of water quantity needed for improving water environment quality and pollutant concentrations were developed for rivers and lakes respectively. The calculation method for the quantity of water transfer was given and the forecasting evaluation of the effect of water transfer was carried out. It was took the project, water transfer from Yangtze River to improve the water quality of rivers in Zhangjiagang City, as an example, and changing principles of water quantity and quality were observed in rivers and lakes through site water transfer experiments. The theory of estimating parameters in inverse problem was used to determine parameters in water quantity and quality models. The water quantity and quality coupled models in river system were applied to calculate the minimal water transfer quantity. The theoretical and technical support for the improvement of water environmental quality in Zhangjiagang City and the project "water transfer form Yangtze River to Taihu Lake" were provided.

  10. A Relationship Framework for Building Information Modeling (BIM Capability in Quantity Surveying Practice and Project Performance

    Directory of Open Access Journals (Sweden)

    Wong, P. F.

    2015-12-01

    Full Text Available Construction industry has suffered from poor project performance and it’s crucial to find out solution to improve this issue. Quantity surveyors (QSs play a key role in managing project cost. However, their method of performing tasks is tedious till affect the project performance. Building information modeling (BIM application is attaining attention in the construction industry as a mean to improve the project performance. However, the adoption is low among QSs due to limited study of the BIM’s capabilities in their profession. This research aims to identify the BIM capabilities in quantity surveying practices and examine its relationship with project performance by developing a relationship framework. Data were collected through questionnaire survey and interview in Malaysia. Questionnaire results revealed that several BIM capabilities were significantly correlated with project performance and they were validated through interview. The relationship framework will guide QSs to focus on the identified BIM capabilities for better project outcomes.La industria de la construcción ha sufrido históricamente desviaciones en las mediciones de los materiales empleados frente a las cantidades proyectadas. Los aparejadores juegan un papel clave en este aspecto como responsables de la recepción de materiales. Sin embargo, el trabajo de medición es tedioso hasta el punto de afectar al rendimiento del proyecto. La aplicación del Building Information Modeling (BIM está logrando mejorar este trabajo. Aun así, su utilización es baja entre los aparejadores debido a la escasa formación recibida sobre las posibilidades del BIM. Esta investigación busca identificar las capacidades del BIM aplicado a la medición de materiales y examinar su relación con el rendimiento del proyecto desarrollando un marco de relación. Mediante encuestas y entrevistas realizadas en Malasia, se obtuvieron datos que revelaron que varias capacidades de BIM se correlacionan

  11. Water Quality and Quantity Modeling for Hydrologic and Policy Decision Making

    Science.gov (United States)

    Rubiano, J.; Giron, E.; Quintero, M.; O'Brien, R.

    2004-12-01

    This paper presents the results of a research project that elucidate the excesses of nitrogen and phosphorous using a spatial-temporal modeling approach. The project uses the approach of integrating biophysical and socio-economic knowledge to offer sound solution to multiple stakeholders within a watershed context. The aim is to promote rural development and solve environmental conflicts by focusing on the internalization of externalities derived from watershed management, triggering the transference of funding from urban to rural populations, making the city invest in environmental goods or services offered by rural environments. The integrated modeling is focused towards identifying causal relationships between land use and management on the one hand, and water quantity/quality and sedimentation downstream on the other. Estimation of the amount of contaminated sediments transported in the study area and its impact is also studied here. The soil runoff information within the study area is obtained considering the characteristics of erosion using a MUSLE model as a sub-model of SWAT model. Using regression analysis, mathematical relationships between rainfall and surface runoff and between land use or management practices and the measured nitrate and phosphate load are established. The methodology first integrates most of the key spatial information available for the site to facilitate envisioning different land use scenarios and their impacts upon water resources. Subsequently, selected alternatives scenarios regarding the identified externalities are analyzed using optimization models. Opportunities for and constraints to promoting co-operation among users are exposed with the aid of economic games in which more sustainable land use or management alternatives are suggested. Strategic alliances and collective action are promoted in order to implement those alternatives that are environmentally sound and economically feasible. Such options are supported by co

  12. A simple clinical model for planning transfusion quantities in heart surgery

    Directory of Open Access Journals (Sweden)

    Biagioli Bonizella

    2011-06-01

    Full Text Available Abstract Background Patients undergoing heart surgery continue to be the largest demand on blood transfusions. The need for transfusion is based on the risk of complications due to poor cell oxygenation, however large transfusions are associated with increased morbidity and risk of mortality in heart surgery patients. The aim of this study was to identify preoperative and intraoperative risk factors for transfusion and create a reliable model for planning transfusion quantities in heart surgery procedures. Methods We performed an observational study on 3315 consecutive patients who underwent cardiac surgery between January 2000 and December 2007. To estimate the number of packs of red blood cells (PRBC transfused during heart surgery, we developed a multivariate regression model with discrete coefficients by selecting dummy variables as regressors in a stepwise manner. Model performance was assessed statistically by splitting cases into training and testing sets of the same size, and clinically by investigating the clinical course details of about one quarter of the patients in whom the difference between model estimates and actual number of PRBC transfused was higher than the root mean squared error. Results Ten preoperative and intraoperative dichotomous variables were entered in the model. Approximating the regression coefficients to the nearest half unit, each dummy regressor equal to one gave a number of half PRBC. The model assigned 4 units for kidney failure requiring preoperative dialysis, 2.5 units for cardiogenic shock, 2 units for minimum hematocrit at cardiopulmonary bypass less than or equal to 20%, 1.5 units for emergency operation, 1 unit for preoperative hematocrit less than or equal to 40%, cardiopulmonary bypass time greater than 130 minutes and type of surgery different from isolated artery bypass grafting, and 0.5 units for urgent operation, age over 70 years and systemic arterial hypertension. Conclusions The regression

  13. EOQ Model for Deteriorating Items with exponential time dependent Demand Rate under inflation when Supplier Credit Linked to Order Quantity

    Directory of Open Access Journals (Sweden)

    Rakesh Prakash Tripathi

    2014-05-01

    Full Text Available In paper (2004 Chang studied an inventory model under a situation in which the supplier provides the purchaser with a permissible delay of payments if the purchaser orders a large quantity. Tripathi (2011 also studied an inventory model with time dependent demand rate under which the supplier provides the purchaser with a permissible delay in payments. This paper is motivated by Chang (2004 and Tripathi (2011 paper extending their model for exponential time dependent demand rate. This study develops an inventory model under which the vendor provides the purchaser with a credit period; if the purchaser orders large quantity. In this chapter, demand rate is taken as exponential time dependent. Shortages are not allowed and effect of the inflation rate has been discussed. We establish an inventory model for deteriorating items if the order quantity is greater than or equal to a predetermined quantity. We then obtain optimal solution for finding optimal order quantity, optimal cycle time and optimal total relevant cost. Numerical examples are given for all different cases. Sensitivity of the variation of different parameters on the optimal solution is also discussed. Mathematica 7 software is used for finding numerical examples.

  14. Innovative characteristics of the new dosimetric model for the human respiratory tract studied by the ICRP appointed Task Group of Committee 2

    CERN Document Server

    Melandri, C; Tarroni, G

    1991-01-01

    In 1984, the ICRP appointed a Task Group of Committee 2 to review and revise, as necessary, the current lung dosimetric model. On the basis of the knowledge acquired during the past 20 years, the Task Group's approach has been to review, in depth, the morphology and physiology of the human respiratory tract, inspirability of aerosols and regional deposition of inhaled particles as functions of aerosol size and breathing parameters, clearance of deposited materials, nature and specific sites of damage to the respiratory system caused by inhaled radioactive substances. In the proposed model, clearance from the three regions of the respiratory tract (extrathoracic ET, fast-clearing thoracic T sub f and slow-clearing thoracic T sub s , comprising lymph nodes) is described in terms of competition between the mechanical processes moving particles, which do not depend on the substances, and those of absorption into the blood, determined solely by the material. A Task Group report will also include models for calcula...

  15. Integrated modeling of water quantity and quality in the Araguari River basin, Brazil

    Directory of Open Access Journals (Sweden)

    Marcio Ricardo Salla

    2014-03-01

    Full Text Available The Araguari River basin has a huge water resource potential. However, population and industrial growth have generated numerous private and collective conflicts of interest in the multiple uses of water, resulting in the need for integrated management of water quantity and quality at the basin scale. This study used the AQUATOOL Decision Support System. The water balance performed by the SIMGES module for the period of October 2006 to September 2011 provided a good representation of the reality of this basin. The parameters studied were dissolved oxygen, biochemical oxygen demand, organic nitrogen, ammonia, nitrate and total phosphorus. The coefficients of biochemical reactions, sedimentation rates and sediment dissolved oxygen release for this period were calibrated and validated in the quality modeling using the GESCAL module. A sensitivity analysis indicated that the coefficients of carbonaceous matter decomposition, nitrification, water temperature, and sediment oxygen demand interfered more significantly in the variables of state. To prevent eutrophication in the Nova Ponte reservoir and in the other cascade reservoirs, the local River Basin Committee should adopt restrictive actions against the use of agricultural fertilizers. On the other hand, in the sub basin of the Uberabinha River, new alternatives for public water supply to the city of Uberlândia and improvements in the treatment efficiency of the main wastewater treatment plant (WWTP should be proposed, since the biochemical oxygen demand, ammonia and total phosphorus failed to meet the requirements of COPAM (2008 in the driest months.

  16. The work of the ICRP dose calculational task group: Issues in implementation of the ICRP dosimetric methodology

    Energy Technology Data Exchange (ETDEWEB)

    Eckerman, K.F. [Oak Ridge National Lab., TN (United States)

    1999-01-01

    Committee 2 of the International Commission on Radiological Protection (ICRP) has had efforts underway to provide the radiation protection community with age-dependent dose coefficients, i.e.g, the dose per unit intake. The Task Group on Dose Calculations, chaired by the author, is responsible for the computation of these coefficients. The Task Group, formed in 1974 to produce ICRP Publication 30, is now international in its membership and its work load has been distributed among the institutions represented on the task group. This paper discusses: (1) recent advances in biokinetic modeling; (2) the recent changes in the dosimetric methodology; (3) the novel computational problems with some of the ICRP quantities; and (4) quality assurance issues which the Task Group has encountered. Potential future developments of the dosimetric framework which might strengthen the relationships with the emerging understanding of radiation risk will also be discussed.

  17. Approximate models for the study of exponential changed quantities: Application on the plasma waves growth rate or damping

    Energy Technology Data Exchange (ETDEWEB)

    Xaplanteris, C. L., E-mail: cxaplanteris@yahoo.com [Plasma Physics Laboratory, IMS, NCSR “Demokritos”, Athens, Greece and Hellenic Army Academy, Vari Attica (Greece); Xaplanteris, L. C. [School of Physics, National and Kapodistrian University of Athens, Athens (Greece); Leousis, D. P. [Technical High School of Athens, Athens (Greece)

    2014-03-15

    Many physical phenomena that concern the research these days are basically complicated because of being multi-parametric. Thus, their study and understanding meets with big if not unsolved obstacles. Such complicated and multi-parametric is the plasmatic state as well, where the plasma and the physical quantities that appear along with it have chaotic behavior. Many of those physical quantities change exponentially and at most times they are stabilized by presenting wavy behavior. Mostly in the transitive state rather than the steady state, the exponentially changing quantities (Growth, Damping etc) depend on each other in most cases. Thus, it is difficult to distinguish the cause from the result. The present paper attempts to help this difficult study and understanding by proposing mathematical exponential models that could relate with the study and understanding of the plasmatic wavy instability behavior. Such instabilities are already detected, understood and presented in previous publications of our laboratory. In other words, our new contribution is the study of the already known plasmatic quantities by using mathematical models (modeling and simulation). These methods are both useful and applicable in the chaotic theory. In addition, our ambition is to also conduct a list of models useful for the study of chaotic problems, such as those that appear into the plasma, starting with this paper's examples.

  18. Optimal Decision-Making in Fuzzy Economic Order Quantity (EOQ Model under Restricted Space: A Non-Linear Programming Approach

    Directory of Open Access Journals (Sweden)

    M. Pattnaik

    2013-08-01

    Full Text Available In this paper the concept of fuzzy Non-Linear Programming Technique is applied to solve an economic order quantity (EOQ model under restricted space. Since various types of uncertainties and imprecision are inherent in real inventory problems they are classically modeled using the approaches from the probability theory. However, there are uncertainties that cannot be appropriately treated by usual probabilistic models. The questions how to define inventory optimization tasks in such environment how to interpret optimal solutions arise. This paper allows the modification of the Single item EOQ model in presence of fuzzy decision making process where demand is related to the unit price and the setup cost varies with the quantity produced/Purchased. This paper considers the modification of objective function and storage area in the presence of imprecisely estimated parameters. The model is developed for the problem by employing different modeling approaches over an infinite planning horizon. It incorporates all concepts of a fuzzy arithmetic approach, the quantity ordered and the demand per unit compares both fuzzy non linear and other models. Investigation of the properties of an optimal solution allows developing an algorithm whose validity is illustrated through an example problem and ugh MATLAB (R2009a version software, the two and three dimensional diagrams are represented to the application. Sensitivity analysis of the optimal solution is also studied with respect to changes in different parameter values and to draw managerial insights of the decision problem.

  19. SAFETY ANALYSIS REPORT FOR PACKAGING, MODEL 9977, ADDENDUM 3, JUSTIFICATION FOR SMALL GRAM QUANTITY CONTENTS

    Energy Technology Data Exchange (ETDEWEB)

    Abramczyk, G.

    2011-10-31

    This Addendum establishes a new family of content envelopes consisting of small quantities of radioactive materials. These content envelopes and specific packing configurations are shown to be subcritical. However, the dose rates of some payloads must be measured and shown to comply with applicable radiation limits. Authorization for shipment of the content envelop requires acceptance of this Addendum by the DOE-HQ certifying official as a supplement to the 9977 SARP Revision 2 and DOE-HQ's subsequent revision of the CoC Revision 10 (which is based on SARP Addendum 2 and SARP Addendum 4) to authorize the additional content envelope. The Small Gram Quantity Content Envelopes and packing configurations will be incorporated in the next revision of the 9977 SARP.

  20. Analisis Ramalan Persediaan Semen Model Economic Order Quantity (EOQ) Pada Toko Material Panglong Jaya Bangun Berbasis Supply Chain Management (SCM)

    OpenAIRE

    Putra, Mirza Gunawansyah

    2016-01-01

    Each company (Services/manufacturing) always needed supplies. Skilled in managing supplies is the result of coveted. Every entrepreneur where able to provide products in accordance with their customers need. One of the many businessman always needed supplies like the Store Building Panglong Jaya Bangun do needed to managed that supplies. The purpose of this research is to find out and analyze qualitatively Model Economic Order Quantity (EOQ) to forecasting that inventory of cement at The s...

  1. Developing economic order quantity model for non-instantaneous deteriorating items in vendor-managed inventory (VMI) system

    Science.gov (United States)

    Tat, Roya; Allah Taleizadeh, Ata; Esmaeili, Maryam

    2015-05-01

    This paper develops an economic order quantity model for non-instantaneous deteriorating items with and without shortages to investigate the performance of the vendor-managed inventory (VMI) system. This model is developed for a two-level supply chain consisting of a single supplier and single retailer with a single non-instantaneous deteriorating item. A numerical example and sensitivity analysis are provided to illustrate how increasing or reducing the related parameters change the optimal values of the decision variables of the two proposed models. The results show that VMI works better and charges lower cost in all conditions.

  2. Medical Simulation Model to Compare SAMMS Inventory Policy with the Average Requisition Quantity Inventory Policy

    Science.gov (United States)

    1990-06-01

    demand C ESTD--The item’s historical standard deviation of its EEX C PCQ --The item’s procurement cycle quantity--includes admin and pit C PCPQ--The...YS, l01,END=51,ERR=900) CTR,UP,MRQ, ICC,ROP,OHA,SPR,WRL, *SUM,ATOT, INUM, PCPQ, PCQ , PCM 101 FORMAT(1X,I5,14X,F8.2,lX,F6.0,4X,Al,F8.0, lX,F9.0,F8.O...WRL SUI41(CTR) =SUM ARQ1(CTR) = ATOT INUMl(CTR) = INUM PCP1(CTR) = PCPQ PC2(CTR) = PCQ PCM1(CTR) = PCM 20 CONTINUE 50 CLOSE (YR) 51 CLOSE (YS) LF = N

  3. [Dosimetric system for assessing doses received by people occupationally exposed to external sources of ionizing radiation].

    Science.gov (United States)

    Brodecki, Marcin; Domienik, Joanna U; Zmyślony, Marek

    2012-01-01

    The current system of dosimetric quantities has been defined by the International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU). Complexity of the system implies the physical nature of ionizing radiation, resulting from the presence of different types of radiation of different ionization capabilities, as well as the individual radiation sensitivity of biological material exposed. According to the latest recommendations, there are three types of dosimeter quantities relevant to radiation protection and radiological assessment of occupational exposure. These are the basic quantities, safety quantities and operational quantities. Dose limits for occupational exposure relate directly to the protection quantities, i.e. the equivalent dose and effective dose, while these quantities are practically unmeasurable in real measurement conditions. For this reason, in the system of dosimetric quantities directly measurable operating volumes were defined. They represent equivalents of the protection quantities that allow for a reliable assessment of equivalent and effective dose by conducting routine monitoring of occupational exposure. This paper presents the characteristics of these quantities, their relationships and importance in assessing individual effects of radiation. Also the methods for their implementation in personal and environmental dosimetry were showcased. The material contained in the article is a compendium of essential information about dosimetric quantities with reference to the contemporary requirements of the law, including the changed annual occupational exposure limit for the lens of the eye. The material is especially addressed to those responsible for dosimetry monitoring in the workplace, radiation protection inspectors and occupational health physicians.

  4. A revised dosimetric characterization of the model S700 electronic brachytherapy source containing an anode-centering plastic insert and other components not included in the 2006 model

    Energy Technology Data Exchange (ETDEWEB)

    Hiatt, Jessica R. [Department of Radiation Oncology, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, Rhode Island 02903 (United States); Davis, Stephen D. [Department of Medical Physics, McGill University Health Centre, Montreal, Quebec H3G 1A4 (Canada); Rivard, Mark J., E-mail: mark.j.rivard@gmail.com [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2015-06-15

    Purpose: The model S700 Axxent electronic brachytherapy source by Xoft, Inc., was characterized by Rivard et al. in 2006. Since then, the source design was modified to include a new insert at the source tip. Current study objectives were to establish an accurate source model for simulation purposes, dosimetrically characterize the new source and obtain its TG-43 brachytherapy dosimetry parameters, and determine dose differences between the original simulation model and the current model S700 source design. Methods: Design information from measurements of dissected model S700 sources and from vendor-supplied CAD drawings was used to aid establishment of an updated Monte Carlo source model, which included the complex-shaped plastic source-centering insert intended to promote water flow for cooling the source anode. These data were used to create a model for subsequent radiation transport simulations in a water phantom. Compared to the 2006 simulation geometry, the influence of volume averaging close to the source was substantially reduced. A track-length estimator was used to evaluate collision kerma as a function of radial distance and polar angle for determination of TG-43 dosimetry parameters. Results for the 50 kV source were determined every 0.1 cm from 0.3 to 15 cm and every 1° from 0° to 180°. Photon spectra in water with 0.1 keV resolution were also obtained from 0.5 to 15 cm and polar angles from 0° to 165°. Simulations were run for 10{sup 10} histories, resulting in statistical uncertainties on the transverse plane of 0.04% at r = 1 cm and 0.06% at r = 5 cm. Results: The dose-rate distribution ratio for the model S700 source as compared to the 2006 model exceeded unity by more than 5% for roughly one quarter of the solid angle surrounding the source, i.e., θ ≥ 120°. The radial dose function diminished in a similar manner as for an {sup 125}I seed, with values of 1.434, 0.636, 0.283, and 0.0975 at 0.5, 2, 5, and 10 cm, respectively. The radial dose

  5. Modelling informally collected quantities of bulky waste and reusable items in Austria

    Energy Technology Data Exchange (ETDEWEB)

    Ramusch, R., E-mail: roland.ramusch@boku.ac.at; Pertl, A.; Scherhaufer, S.; Schmied, E.; Obersteiner, G.

    2015-10-15

    Highlights: • Informal collectors from Hungary collect bulky waste and reusable items in Austria. • Two methodologies were applied to estimate the informally collected quantities. • Both approaches lead to an estimation of roughly 100,000 t p.a. informally collected. • The formal Austrian system collects 72 kg/cap/yr of bulky waste, WEE & scrap metal. • Informal collection amounts to approx. 12 kg/cap/yr. - Abstract: Disparities in earnings between Western and Eastern European countries are the reason for a well-established informal sector actively involved in collection and transboundary shipment activities from Austria to Hungary. The preferred objects are reusable items and wastes within the categories bulky waste, WEEE and metals, intended to be sold on flea markets. Despite leading to a loss of recyclable resources for Austrian waste management, these informal activities may contribute to the extension of the lifetime of certain goods when they are reused in Hungary; nevertheless they are discussed rather controversially. The aim of this paper is to provide objective data on the quantities informally collected and transhipped. The unique activities of informal collectors required the development and implementation of a new set of methodologies. The concept of triangulation was used to verify results obtained by field visits, interviews and a traffic counting campaign. Both approaches lead to an estimation of approx. 100,000 t per year of reusable items informally collected in Austria. This means that in addition to the approx. 72 kg/cap/yr formally collected bulky waste, bulky waste wood, household scrap (excluding packaging) and WEEE, up to a further 12 kg/cap/yr might, in the case that informal collection is abandoned, end up as waste or in the second-hand sector.

  6. Creation and application of voxelised dosimetric models, and a comparison with the current methodology as used for the International Commission on Radiological Protection's Reference Animals and Plants.

    Science.gov (United States)

    Higley, K; Ruedig, E; Gomez-Fernandez, M; Caffrey, E; Jia, J; Comolli, M; Hess, C

    2015-06-01

    Over the past decade, the International Commission on Radiological Protection (ICRP) has developed a comprehensive approach to environmental protection that includes the use of Reference Animals and Plants (RAPs) to assess radiological impacts on the environment. For the purposes of calculating radiation dose, the RAPs are approximated as simple shapes that contain homogeneous distributions of radionuclides. As uncertainties in environmental dose effects are larger than uncertainties in radiation dose calculation, some have argued against more realistic dose calculation methodologies. However, due to the complexity of organism morphology, internal structure, and density, dose rates calculated via a homogenous model may be too simplistic. The purpose of this study is to examine the benefits of a voxelised phantom compared with simple shapes for organism modelling. Both methods typically use Monte Carlo methods to calculate absorbed dose, but voxelised modelling uses an exact three-dimensional replica of an organism with accurate tissue composition and radionuclide source distribution. It is a multi-stage procedure that couples imaging modalities and processing software with Monte Carlo N-Particle. These features increase dosimetric accuracy, and may reduce uncertainty in non-human biota dose-effect studies by providing mechanistic answers regarding where and how population-level dose effects arise.

  7. Radiation quantities: significance of the angular and energy distribution of the radiation field

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, M.; Perks, C.A. (AEA Corporate Safety Directorate, Harwell (United Kingdom)); Thomas, D.J.; Naismith, O.F. (National Physical Lab., Teddington (United Kingdom))

    1994-01-01

    This paper discusses the effects of changing from the old to new (ICRP 60 and ICRU 47) dosimetric quantities, and the relationship between quantities, as a function of the energy and angular distribution, for practical radiation fields. It considers: X rays, gamma rays, neutrons and beta rays; reviews the limited data on practical energy and angular distributions for photons and neutrons in the workplace; and calculates relevant dosimetric quantities based on realistic assumptions. The results are used to illustrate how the relationship between quantities might vary in practical fields and to draw conclusions about the implications of recent ICRP and ICRU publications. (Author).

  8. Modelling informally collected quantities of bulky waste and reusable items in Austria.

    Science.gov (United States)

    Ramusch, R; Pertl, A; Scherhaufer, S; Schmied, E; Obersteiner, G

    2015-10-01

    Disparities in earnings between Western and Eastern European countries are the reason for a well-established informal sector actively involved in collection and transboundary shipment activities from Austria to Hungary. The preferred objects are reusable items and wastes within the categories bulky waste, WEEE and metals, intended to be sold on flea markets. Despite leading to a loss of recyclable resources for Austrian waste management, these informal activities may contribute to the extension of the lifetime of certain goods when they are reused in Hungary; nevertheless they are discussed rather controversially. The aim of this paper is to provide objective data on the quantities informally collected and transhipped. The unique activities of informal collectors required the development and implementation of a new set of methodologies. The concept of triangulation was used to verify results obtained by field visits, interviews and a traffic counting campaign. Both approaches lead to an estimation of approx. 100,000 t per year of reusable items informally collected in Austria. This means that in addition to the approx. 72 kg/cap/yr formally collected bulky waste, bulky waste wood, household scrap (excluding packaging) and WEEE, up to a further 12 kg/cap/yr might, in the case that informal collection is abandoned, end up as waste or in the second-hand sector.

  9. Integrated Inventory Model for Deteriorating Items with Price-Dependent Demand under Quantity-Dependent Trade Credit

    Directory of Open Access Journals (Sweden)

    Karuppuchamy Annadurai

    2013-01-01

    Full Text Available This paper explores an integrated inventory model when the deterioration rate follows exponential distribution under trade credit. Here, it is assumed that demand rate is a function of selling price and the permissible delay in payment depends on the order quantity. In the model shortages are completely backlogged. The maximization of the total profit per unit of time is taken as the objective function to study the retailer’s optimal ordering policy. This paper also presents a practical application example where the proposed inventory model is utilized to support business decision making. Particularly, the model developed in the paper could be useful in the area of supply chain management. Finally, sensitivity analysis of the optimal solution with respect to major parameters is carried out. Our result illustrates that this model can be quite useful in determining the optimal ordering policy when the trade credit period is being analyzed.

  10. Short-term prediction of the influent quantity time series of wastewater treatment plant based on a chaos neural network model

    Institute of Scientific and Technical Information of China (English)

    LI Xiaodong; ZENG Guangming; HUANG Guohe; LI Jianbing; JIANG Ru

    2007-01-01

    By predicting influent quantity,a wastewater treatment plant (WWTP) can be well controlled.The nonlinear dynamic characteristic of WWTP influent quantity time series was analyzed,with the assumption that the series was predictable.Based on this,a short-term forecasting chaos neural network model of WWTP influent quantity was built by phase space reconstruction.Reasonable forecasting results were achieved using this method.

  11. Water Quantity and Quality Models Applied to the Jucar River Basin, Spain

    OpenAIRE

    Paredes Arquiola, Javier; Andreu Álvarez, Joaquín; Martín Monerris, Miguel; Solera Solera, Abel

    2010-01-01

    “The final publication is available at Springer via http://dx.doi.org/ 10.1007/s11269-010-9578-z ”. Traditionally, water quality modelling has focused on modelling individual water bodies. However, water quality management problems must be analyzed at the basin scale. European Water Framework Directive (WFD) requires introducing physical, chemical and biological aspects into the management of water resources systems. Water quality modelling at a basin scale presents the advantage of incorp...

  12. On the use of advanced numerical models for the evaluation of dosimetric parameters and the verification of exposure limits at workplaces.

    Science.gov (United States)

    Catarinucci, L; Tarricone, L

    2009-12-01

    With the next transposition of the 2004/40/EC Directive, employers will become responsible for the electromagnetic field level at the workplace. To make this task easier, the scientific community is compiling practical guidelines to be followed. This work aims at enriching such guidelines, especially for the dosimetric issues. More specifically, some critical aspects related to the application of numerical dosimetric techniques for the verification of the safety limit compliance have been highlighted. In particular, three different aspects have been considered: the dosimetric parameter dependence on the shape and the inner characterisation of the exposed subject as well as on the numerical algorithm used, and the correlation between reference limits and basic restriction. Results and discussions demonstrate how, even by using sophisticated numerical techniques, in some cases a complex interpretation of the result is mandatory.

  13. Questioning the quantity equation using an agent-based computational model

    DEFF Research Database (Denmark)

    Bruun, Charlotte

    2000-01-01

    by Stutzel (1954), argues that the functional relationship may as well be negative. Even focusing the money needed to carry out transactions, there is no immediate answer to the question of the functional relationship between trade turnover and money demand. An agent-based computational model is used...

  14. Experimental study and modeling of the deuterium releasing quantity in a pulsed vacuum arc discharge with a metal deuteride cathode

    Science.gov (United States)

    Liu, Fei-Xiang; Long, Ji-Dong; Zheng, Le; Dong, Pan; Li, Chen; Chen, Wei

    2017-04-01

    The pulsed vacuum arc discharge using a metal deuteride cathode is widely applied as a deuterium ion source, where the upper limit of the deuterium ion yield is largely determined by the deuterium releasing quantity (DRQ) from the cathode. This work aims to measure the DRQ at various discharge conditions, and meanwhile develop a simple thermoelectric model to evaluate the deuterium liberation from different sources, such as the crater vicinity during the arc power-on phase and the hot crater in the afterglow. The calculated DRQ are in accordance with the experimental results obtained by measuring the D2 pressure evolution in the early afterglow using a quadrupole mass spectrometer. Furthermore, the model reveals that at low arc current (<10 A), the DRQ orginates dominantly from the crater vicinity, leading to a low conversion efficiency of the released deuterium to ions and a high D:Ti elemental ratio in the released cathode vapor.

  15. Economic order quantity model for deteriorating items with imperfect quality and permissible delay on payment

    Directory of Open Access Journals (Sweden)

    Chandra K. Jaggi

    2011-04-01

    Full Text Available In the classical inventory models, most of the time the issue of quality has not been considered. However, in realistic environment, it can be observed that there may be some defective items in an ordered lot, because of these defective items retailer incurs additional cost due to rejection, repair and refund etc. Thus, inspection/screening of lot becomes indispensible in most of the organizations. Moreover, it plays a very essential role when items are of deteriorating in nature. Further, it is generally assumed that payment will be made to the supplier for the goods immediately after receiving the consignment. Whereas, in practice, supplier does offers a certain fixed period to the retailer for settling the account. During this period, supplier charges no interest, but beyond this period interest is being charged as has been agreed upon. On the other hand, retailer can earn interest on the revenue generated during this period. Keeping this scenario in mind, an attempt has been made to formulate an inventory model for deteriorating items with imperfect quality under permissible delay in payments. Results have been validated with the help of a numerical example using Matlab7.0.1. Comprehensive sensitivity analysis has also been presented.

  16. Progress toward forecasting product quality and quantity of mammalian cell culture processes by performance-based modeling.

    Science.gov (United States)

    Schmidberger, Timo; Posch, Christoph; Sasse, Alexandra; Gülch, Carina; Huber, Robert

    2015-01-01

    The production of biopharmaceuticals requires highly sophisticated, complex cell based processes. Once a process has been developed, acceptable ranges for various control parameters are typically defined based on process characterization studies often comprising several dozens of small scale bioreactor cultivations. A lot of data is generated during these studies and usually only the information needed to define acceptable ranges is processed in more detail. Making use of the wealth of information contained in such data sets, we present here a methodology that uses performance data (such as metabolite profiles) to forecast the product quality and quantity of mammalian cell culture processes based on a toolbox of advanced statistical methods. With this performance based modeling (PBM) the final product concentration and 12 quality attributes (QAs) for two different biopharmaceutical products were predicted in daily intervals throughout the main stage process. The best forecast was achieved for product concentration in a very early phase of the process. Furthermore, some glycan isoforms were predicted with good accuracy several days before the bioreactor was harvested. Overall, PBM clearly demonstrated its capability of early process endpoint prediction by only using commonly available data, even though it was not possible to predict all QAs with the desired accuracy. Knowing the product quality prior to the harvest allows the manufacturer to take counter measures in case the forecasted quality or quantity deviates from what is expected. This would be a big step towards real-time release, an important element of the FDA's PAT initiative. © 2015 American Institute of Chemical Engineers.

  17. Communicating about quantity without a language model: number devices in homesign grammar.

    Science.gov (United States)

    Coppola, Marie; Spaepen, Elizabet; Goldin-Meadow, Susan

    2013-01-01

    All natural languages have formal devices for communicating about number, be they lexical (e.g., two, many) or grammatical (e.g., plural markings on nouns and/or verbs). Here we ask whether linguistic devices for number arise in communication systems that have not been handed down from generation to generation. We examined deaf individuals who had not been exposed to a usable model of conventional language (signed or spoken), but had nevertheless developed their own gestures, called homesigns, to communicate. Study 1 examined four adult homesigners and a hearing communication partner for each homesigner. The adult homesigners produced two main types of number gestures: gestures that enumerated sets (cardinal number marking), and gestures that signaled one vs. more than one (non-cardinal number marking). Both types of gestures resembled, in form and function, number signs in established sign languages and, as such, were fully integrated into each homesigner's gesture system and, in this sense, linguistic. The number gestures produced by the homesigners' hearing communication partners displayed some, but not all, of the homesigners' linguistic patterns. To better understand the origins of the patterns displayed by the adult homesigners, Study 2 examined a child homesigner and his hearing mother, and found that the child's number gestures displayed all of the properties found in the adult homesigners' gestures, but his mother's gestures did not. The findings suggest that number gestures and their linguistic use can appear relatively early in homesign development, and that hearing communication partners are not likely to be the source of homesigners' linguistic expressions of non-cardinal number. Linguistic devices for number thus appear to be so fundamental to language that they can arise in the absence of conventional linguistic input. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Methods, Devices and Computer Program Products Providing for Establishing a Model for Emulating a Physical Quantity Which Depends on at Least One Input Parameter, and Use Thereof

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention proposes methods, devices and computer program products. To this extent, there is defined a set X including N distinct parameter values x_i for at least one input parameter x, N being an integer greater than or equal to 1, first measured the physical quantity Pm1 for each...... based on the Vandermonde matrix and the first measured physical quantity according to the equation W=(VMT*VM)-1*VMT*Pm1. The model is iteratively refined so as to obtained a desired emulation precision.; The model can later be used to emulate the physical quantity based on input parameters or logs taken...

  19. SU-E-T-650: Quantification and Modeling of the Dosimetric Impact of the IBEAM Evo Treatment Couchtop EP (Elekta) in VMAT

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R [The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei (China); Mannheim Medical Center, Mannheim, Baden-Wurttemberg (Germany); Bai, W [The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei (China); Fleckenstein, J [Mannheim Medical Center, Mannheim, Baden-Wurttemberg (Germany)

    2015-06-15

    Purpose: quantification and modelling of the dosimetric impact of the treatment couch in Monaco Treatment Planning System. Methods: The attenuation characteristics of couchtop EP was evaluated for two different photon acceleration potentials (6MV and 10MV) for a field size of (10×10) cm2. Phantom positions in A-B direction: on the left half, in the center and on the right half of the couch. Dose measurements of couch attenuation were performed at gantry angles from 180° to 122°, using a 0.125cc semiflex ionization chamber isocentrically placed in the center of a homogeneous cylindric sliced RW3 phantom. Each experimental setup was first measured on the LINAC and then reproduced in the TPS. By adjusting the relative-to-water electron density (ED) values of the couch, the measured attenuation was replicated. The simulated results were evaluated by comparing the measurements and simulations. Results: Without the couch model included the maximum difference between measured and calculated dose was 5.5% (5.1%) and 6.6% (6.1%) for 2 mm and 5 mm voxel size, when the phantom was positioned on the left (center). The couch model was included in the TPS with a uniform ED of 0.18 or a 2 component model with a fiber ED= 0.6 and foam core ED= 0.1. After including the treatment couch, the mean dose attenuation was reduced from 2.8% without couch included to (0.0, 0.8, −0.2, 0.6)%. The 4 different values represent the 1 and 2 components model and 2 and 5 mm voxel grid size. Conclusion: For a uniform relative-to-water couch electron density of 0.18 a good agreement between measured and calculated dose distributions was obtained for all different energies, voxel grid spacings and gantry angles. Therefore, we conclude that the Monaco couch model accurately describes the dose perturbations due to the presence of the patient couch and should therefore be used during treatment planning. This project is supported by Technology Foundation for Selected Overseas Chinese Scholar

  20. Constrained Probabilistic Economic Order Quantity Model under Varying Order Cost and Zero Lead Time Via Geometric Programming

    Directory of Open Access Journals (Sweden)

    Kotb A.E.H.M. Kotb

    2011-01-01

    Full Text Available Problem statement: In this study, we provide a simple method to determine the inventory policy of probabilistic single-item Economic Order Quantity (EOQ model, that has varying order cost and zero lead time. The model is restricted to the expected holding cost and the expected available limited storage space. Approach: The annual expected total cost is composed of three components (expected purchase cost, expected ordering cost and expected holding cost. The problem is then solved using a modified Geometric Programming method (GP. Results: Using the annual expected total cost to determine the optimal solutions, number of periods, maximum inventory level and minimum expected total cost per period. A classical model is derived and numerical example is solved to confirm the model. Conclusion/Recommendations: The results indicated the total cost decreased with changes in optimal solutions. Possible future extension of this model was include continuous decreasing ordering function of the number of periods and introducing expected annual demand rate as a decision variable.

  1. Modeling of gamma ray energy-absorption buildup factors for thermoluminescent dosimetric materials using multilayer perceptron neural network

    DEFF Research Database (Denmark)

    Kucuk, Nil; Manohara, S.R.; Hanagodimath, S.M.

    2013-01-01

    V, and for penetration depths up to 10 mfp (mean-free-path). The MLPNNs have been trained by a Levenberg–Marquardt learning algorithm. The developed model is in 99% agreement with the ANSI/ANS-6.4.3 standard data set. Furthermore, the model is fast and does not require tremendous computational efforts. The estimated BA...

  2. Challenges in modelling of water quantity and quality in two contrasting meso-scale catchments in Poland

    Directory of Open Access Journals (Sweden)

    Marcinkowski Paweł

    2016-12-01

    Full Text Available This study presents an application of the SWAT model (Soil and Water Assessment Tool in two meso-scale catchments in Poland (Upper Narew and Barycz, contrasting in terms of human pressures on water quantity and quality. The main objective was multi-variable and multi-site calibration and validation of the model against daily discharge, sediment and nutrient loads as well as discussion of challenges encountered in calibration phase. Multi-site calibration and validation gave varied results ranging from very good (daily discharge to acceptable (sediment, nitrogen and phosphorus loads in most of gauges and rather poor (individual gauges for all variables in both catchments. The calibrated models enabled spatial quantification of water yield, sediment and nutrient loads, indicating areas of special concern in terms of pollution, as well as estimation of contribution of pollution from different sources, indicating agriculture as the most important source in both catchments. During the calibration process a number of significant issues were encountered: (i global vs. local parametrization, (ii simulation of different pools of water quality parameters in reservoirs and streams and (iii underestimation of NO3-N loads in winter due to farmers practices. Discussion of these issues is hoped to aid SWAT model users in Poland in a deeper understanding of mechanisms of multi-variable and multi-site calibration.

  3. Incorrect dosimetric leaf separation in IMRT and VMAT treatment planning

    DEFF Research Database (Denmark)

    Sjölin, Maria; Edmund, Jens Morgenthaler

    2016-01-01

    PURPOSE: Dynamic treatment planning algorithms use a dosimetric leaf separation (DLS) parameter to model the multi-leaf collimator (MLC) characteristics. Here, we quantify the dosimetric impact of an incorrect DLS parameter and investigate whether common pretreatment quality assurance (QA) methods...... can detect this effect. METHODS: 16 treatment plans with intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) technique for multiple treatment sites were calculated with a correct and incorrect setting of the DLS, corresponding to a MLC gap difference of 0.5mm...

  4. SU-C-303-03: Dosimetric Model of the Beagle Needed for Pre-Clinical Testing of Radiopharmaceuticals

    Energy Technology Data Exchange (ETDEWEB)

    Shang, M; Sands, M; Bolch, W [University of Florida, Gainesville, FL (United States)

    2015-06-15

    Purpose: Large animal models, most popularly beagles, have been crucial surrogates to humans in determining radiation safety levels of radiopharmaceuticals. This study aims to develop a detailed beagle phantom to accurately approximate organ absorbed doses for therapy nuclear medicine preclinical studies. Methods: A 3D NURBS model was created subordinate to a whole body CT of an adult beagle. Bones were harvested and CT imaged to offer macroscopic skeletal detail. Samples of trabecular spongiosa were cored and imaged to offer microscopic skeletal detail for bone trabeculae and marrow volume fractions. Results: Organ masses in the model are typical of an adult beagle. Trends in volume fractions for skeletal dosimetry are fundamentally similar to those found in existing models of other canine species. Conclusion: This work warrants its use in further investigations of radiation transport calculation for electron and photon dosimetry. This model accurately represents the anatomy of a beagle, and can be directly translated into a useable geometry for a voxel-based Monte Carlo radiation transport program such as MCNP6. Work supported by a grant from the Hyundai Hope on Wheels Foundation for Pediatric Cancer Research.

  5. GIS-based models for water quantity and quality assessment in the Júcar River Basin, Spain, including climate change effects.

    Science.gov (United States)

    Ferrer, Javier; Pérez-Martín, Miguel A; Jiménez, Sara; Estrela, Teodoro; Andreu, Joaquín

    2012-12-01

    This paper describes two different GIS models - one stationary (GeoImpress) and the other non-stationary (Patrical) - that assess water quantity and quality in the Júcar River Basin District, a large river basin district (43,000km(2)) located in Spain. It aims to analyze the status of surface water (SW) and groundwater (GW) bodies in relation to the European Water Framework Directive (WFD) and to support measures to achieve the WFD objectives. The non-stationary model is used for quantitative analysis of water resources, including long-term water resource assessment; estimation of available GW resources; and evaluation of climate change impact on water resources. The main results obtained are the following: recent water resources have been reduced by approximately 18% compared to the reference period 1961-1990; the GW environmental volume required to accomplish the WFD objectives is approximately 30% of the GW annual resources; and the climate change impact on water resources for the short-term (2010-2040), based on a dynamic downscaling A1B scenario, implies a reduction in water resources by approximately 19% compared to 1990-2000 and a reduction of approximately 40-50% for the long-term (2070-2100), based on dynamic downscaling A2 and B2 scenarios. The model also assesses the impact of various fertilizer application scenarios on the status of future GW quality (nitrate) and if these future statuses will meet the WFD requirements. The stationary model generates data on the actual and future chemical status of SW bodies in the river basin according to the modeled scenarios and reflects the implementation of different types of measures to accomplish the Urban Waste Water Treatment Directive and the WFD. Finally, the selection and prioritization of additional measures to accomplish the WFD are based on cost-effectiveness analysis.

  6. An Economic Order Quantity Model with Completely Backordering and Nondecreasing Demand under Two-Level Trade Credit

    Directory of Open Access Journals (Sweden)

    Zohreh Molamohamadi

    2014-01-01

    Full Text Available In the traditional inventory system, it was implicitly assumed that the buyer pays to the seller as soon as he receives the items. In today’s competitive industry, however, the seller usually offers the buyer a delay period to settle the account of the goods. Not only the seller but also the buyer may apply trade credit as a strategic tool to stimulate his customers’ demands. This paper investigates the effects of the latter policy, two-level trade credit, on a retailer’s optimal ordering decisions within the economic order quantity framework and allowable shortages. Unlike most of the previous studies, the demand function of the customers is considered to increase with time. The objective of the retailer’s inventory model is to maximize the profit. The replenishment decisions optimally are obtained using genetic algorithm. Two special cases of the proposed model are discussed and the impacts of parameters on the decision variables are finally investigated. Numerical examples demonstrate the profitability of the developed two-level supply chain with backorder.

  7. Modeling Water Quantity and Quality in the Devils Lake Watershed Coupling SWAT and CE-QUAL-W2.

    Science.gov (United States)

    Shabani, A.; Zhang, X.; Ell, M.

    2016-12-01

    Devils Lake is a terminal lake in the sub-basin of the Red River of the North basin in northeastern North Dakota. During the last two decades, the lake level has risen by nearly 10 m, causing floods that have costed more than 1 billion USD in mitigation measures. Another increase of approximate 1.5 m in the lake level would cause water to spill naturally into the Sheyenne River. To alleviate this potential yet catastrophic spillage, two artificial outlets were constructed. However, artificially draining water to the Sheyenne River raises a concern of water quality because the Devils Lake water contains significantly higher concentrations of dissolved solids, particularly sulfate, than the surrounding water bodies. In this study, the Soil and Water Assessment Tool (SWAT) coupled with CE-QUAL-W2 were used to simulate water quantity and quality over the watershed and the lake. The SWAT model performed well to simulate daily flow, total suspend sediment (TSS), total nitrogen (TN), and phosphorous (TP) in the tributaries. The developed SWAT model is able to simulate to the lake level with a root mean square error of 0.35 m for the period time from 1995 to 2014.The CE-QUAL-W2 successfully simulated sulfate concentration (R2=0.4 and PBIAS < 6%) and concentrations of TP in the lake that are in general agreement with the observations. Keywords: Devils Lake, flooding, SWAT, CE-QUAL-W2, water quality

  8. Comparison of dosimetric mapping of radiation induced skin ulcer animal model in Nud mice and Wistar rat

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Nelson M.; Mosca, Rodrigo C.; Ferreira, Danilo C.; Somessari, Elizabeth S.R.; Silveira, Carlos Gaia da; Dornelles, Leonardo D.P.; Bueno, Carmem C.; Mathor, Monica B., E-mail: nelsonnininho@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Skin ulcer (SU) is the damage caused to the skin by ionizing radiation, becoming evident at the end or after the conclusion of radiotherapeutic treatments. Technological advances have enabled dose increases in radiotherapy protocols, augmenting SU cases. In order to investigate potential therapies for the SU, an animal model (AM) was devised for Wistar rats, based upon the AM of the Nud mice. The AM dose rate (DR) was measured with silicium diode in the gamma irradiator and lead blocks. Three animals were positioned into immobilizers with their dorsal region skin pinched and held up by a suture point fixed in the immobilizer and exposed to 85 Gy. The DR variation in the immobilizer tangential point with the source median plane was non-significant, thus establishing an average DR. Such shielding reduced the DR in the rat in more than 93%. The difference in the immobilizer's dimensions impaired the comparison between the DRs; nevertheless, the DR comparison in the immobilizer tangential point with the source median plane became the reference point for AM comparison. The appearance of SU symptoms and their maximum extensions were similar, notwithstanding the difference regarding their healing periods. The specified dose induced the SU emerging. Mass variation exerted no influence onto the healing, despite having age affected it. The animals, throughout and after the experiment, showed normal health with just the SU symptoms. This work granted us the AM for the Wistar rats, which shall reinforce the investigation of new therapies for SU treatment. (author)

  9. A balanced calibration of water quantity and quality by multi-objective optimization for integrated water system model

    Science.gov (United States)

    Zhang, Yongyong; Shao, Quanxi; Taylor, John A.

    2016-07-01

    Due to the high interactions among multiple processes in integrated water system models, it is extremely difficult, if not impossible, to achieve reasonable solutions for all objectives by using the traditional step-by-step calibration. In many cases, water quantity and quality are equally important but their objectives in model calibration usually conflict with each other, so it is not a good practice to calibrate one after another. In this study, a combined auto-calibration multi-process approach was proposed for the integrated water system model (HEQM) using a multi-objective evolutionary algorithm. This ensures that the model performance among inseparable or interactive processes could be balanced by users based on the Pareto front. The Huai River Basin, a highly regulated and heavily polluted region of China, was selected as a case study. The hydrological and water quality parameters of HEQM were calibrated simultaneously based on the observed series of runoff and ammonia-nitrogen (NH4-N) concentrations. The results were compared with those of the step-by-step calibration to demonstrate the rationality and feasibility of the multi-objective approach. The results showed that a Pareto optimal front was formed and could be divided into three clear sections based on the elastic coefficient of model performance between NH4-N and runoff, i.e., the dominated section for NH4-N improvement, the trade-off section between NH4-N and runoff, and the dominated section for runoff improvement. The trade-off of model performance between runoff and NH4-N concentration was clear. The results of the step-by-step calibration fell in the dominated section for NH4-N improvement, where just the optimum of the runoff simulation was achieved with a large potential to improve NH4-N simulation without a significant degradation of the runoff simulation. The overall optimal solutions for all the simulations appeared in the trade-off section. Therefore, the Pareto front provided different

  10. Dosimetric Characteristics of a Two-Dimensional Diode Array Detector Irradiated with Passively Scattered Proton Beams

    Energy Technology Data Exchange (ETDEWEB)

    Liengsawangwong, Praimakorn; Sahoo, Nanayan; Ding, Xiaoning; Lii, MingFwu; Gillin, Michale T.; Zhu, Xiaorong Ronald, E-mail: xrzhu@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States)

    2015-07-30

    Purpose: To evaluate the dosimetric characteristics of a two-dimensional (2D) diode array detector irradiated with passively scattered proton beams. Materials and Methods: A diode array detector, MapCHECK (Model 1175, Sun Nuclear, Melbourne, FL, USA) was characterized in passive-scattered proton beams. The relative sensitivity of the diodes and absolute dose calibration were determined using a 250 MeV beam. The pristine Bragg curves (PBCs) measured by MapCHECK diodes were compared with those of an ion chamber using a range shift method. The water-equivalent thickness (WET) of the diode array detector’s intrinsic buildup also was determined. The inverse square dependence, linearity, and other proton dosimetric quantities measured by MapCHECK were also compared with those of the ion chambers. The change in the absolute dose response of the MapCHECK as a function of accumulated radiation dose was used as an indicator of radiation damage to the diodes. 2D dose distribution with and without the compensator were measured and compared with the treatment planning system (TPS) calculations. Results: The WET of the MapCHECK diode’s buildup was determined to be 1.7 cm. The MapCHECK-measured PBC were virtually identical to those measured by a parallel-plate ion chamber for 160, 180, and 250 MeV proton beams. The inverse square results of the MapCHECK were within ±0.4% of the ion chamber results. The linearity of MapCHECK results was within 1% of those from the ion chamber as measured in the range between 10 and 300 MU. All other dosimetric quantities were within 1.3% of the ion chamber results. The 2D dose distributions for non-clinical fields without compensator and the patient treatment fields with the compensator were consistent with the TPS results. The absolute dose response of the MapCHECK was changed by 7.4% after an accumulated dose increased by 170 Gy. Conclusions: The MapCHECK is a convenient and useful tool for 2D dose distribution measurements using passively

  11. Thermal quantities of 46Ti

    Science.gov (United States)

    Rahmatinejad, A.; Razavi, R.; Kakavand, T.

    2015-07-01

    Thermodynamic quantities of 46Ti have been calculated in the framework of the BCS model with inclusion of modified nuclear pairing gap (MPBCS) that was proposed in our previous publication. Using modified paring gap results in an S-shaped heat capacity curve at critical temperature with a smooth behavior instead of singular behavior of the same curve in the BCS calculations. In addition the thermal quantities have been extracted within the framework of a canonical ensemble according to the new experimental data on nuclear level densities measured by the Oslo group. Comparison shows a good agreement between our calculations in MPBCS and the extracted quantities in the canonical ensemble framework.

  12. Mapping spatio-temporal variation of grassland quantity and quality using MERIS data and the PROSAIL model

    NARCIS (Netherlands)

    Si, Y.; Schlerf, M.; Zurita-Milla, R.; Skidmore, A.K.; Wang, T.

    2012-01-01

    Accurate estimates of the quantity and quality of grasslands, as they vary in space and time and from regional to global scales, furthers our understanding of grassland ecosystems. The Medium Resolution Imaging Spectrometer (MERIS) is a promising sensor for measuring and monitoring grasslands due to

  13. Replenishment policy for Entropic Order Quantity (EnOQ model with two component demand and partial back-logging under inflation

    Directory of Open Access Journals (Sweden)

    Bhanupriya Dash

    2017-09-01

    Full Text Available Background: Replenishment policy for entropic order quantity model with two component demand and partial backlogging under inflation is an important subject in the stock management. Methods: In this paper an inventory model for  non-instantaneous  deteriorating items with stock dependant consumption rate and partial back logged in addition the effect of inflection and time value of money on replacement policy with zero lead time consider was developed. Profit maximization model is formulated by considering the effects of partial backlogging under inflation with cash discounts. Further numerical example presented to evaluate the relative performance between the entropic order quantity and EOQ models separately. Numerical example is present to demonstrate the developed model and to illustrate the procedure. Lingo 13.0 version software used to derive optimal order quantity and total cost of inventory. Finally sensitivity analysis of the optimal solution with respect to different parameters of the system carried out. Results and conclusions: The obtained inventory model is very useful in retail business. This model can extend to total backorder.

  14. An environmental fairness based optimisation model for the decision-support of joint control over the water quantity and quality of a river basin

    Science.gov (United States)

    Yu, Sen; He, Li; Lu, Hongwei

    2016-04-01

    This paper presented a new environmental fairness based optimisation model (EFOM) for the decision-support of water resources management and water pollution control at the watershed scale. The model integrated three prediction modules for water consumption and pollutant discharge (WCPD), environmental Gini coefficient (EGC) and water quality (WASP). The model is capable of optimizing the total discharge quantity in the whole basin and controlling units both spatially and temporally, and addressing the conflicts between environmental fairness and efficiency. The model was applied to the Songhua River basin, attempting to support decision-making of joint control over the water quantity and quality. Validation of the WASP module showed that the simulation agreed well with water quality monitoring values (2013) in the Harbin section. Results from the EFOM model also indicated that the water environment in the Harbin section would be improved significantly by effectively controlling the total pollution discharge. The identified optimal strategy obtained from the EFOM showed that the percentage of water in good quality reaches 72% in 2020, suggesting that the strategy would guarantee the planning goals of The China Action Plan for Water Pollution Control to be satisfied. Hence, the modelling under the consideration of environmental fairness can be a new attempt, which is beneficial to optimal joint control of water quantity and water quality at the watershed scale.

  15. An Online Detection Model of Granary Storage Quantity%粮仓储粮数量在线检测模型

    Institute of Scientific and Technical Information of China (English)

    张德贤; 杨铁军; 傅洪亮; 樊超; 张元

    2014-01-01

    Granary storage quantity online detection is a key technology for national food quantity safety, and it is also an important content of grain inventory check. According to the randomness of the granary pressure distribution, a new measurement method based on the estimation of zero internal friction pressure at the bottom of granary is proposed. First, a granary pressure sensor layout model is set up, in which the storage quantity detection accuracy and reliability of the detection system are considered comprehensively. Then, the methods of eliminating the grain heap bottom and side pressure distribution randomness and compensating side friction are presented. The granary storage quantity detection model based on the mean of the bottom pressure sensor values and a fast modeling method are proposed in the end. Experiment results show that the error of the proposed storage quantity detection model is far less than 3%and that the system cost is low, which can meet the actual need of real-time online monitoring of national grain storage quantity and distribution.%粮仓储粮数量在线检测是国家粮食数量安全的重要保障技术,是粮食库存检查的重要内容。本文根据储粮数量在线检测精度和可靠性的要求,针对粮仓压强分布的随机性,提出了基于粮仓底面零内摩擦压强估计的粮仓储粮数量检测的新思路,建立了粮仓压力传感器布置模型,给出了粮堆底面与侧面压力分布随机性消除和侧面摩擦力影响补偿的具体方法,提出了基于底面压力传感器检测均值的粮仓储粮数量检测模型和快速建模方法。实仓实验结果表明,所提出的储粮数量检测模型检测误差远小于3%,且检测系统成本低,可有效满足国家粮库储粮数量在线实时监测的实际需要。

  16. An Ordering Model with Quantity Discount under JIT Environment%JIT环境下基于数量折扣的订货模型研究

    Institute of Scientific and Technical Information of China (English)

    郭涛; 刘艳锐

    2012-01-01

    针对上游供应链厂商提供数量折扣情况,将传统采购中的数量折扣同JIT采购结合起来,建立了一个基于数量折扣的综合订货模型.模型探讨了在典型的JIT采购方式“一次订购多次送货”的基础上,针对上游供应链厂商提供数量折扣安排的情况,供应链下游厂商如何选择最优的订货策略:将订货量、送货时点以及送货量作为决策变量,考虑允许缺货且各送货区间需求不确定的情况.运用遗传算法对问题进行求解,并给出了数值算例.%How a Manufacturer can structure the terms of purchasing strategy under JIT environment when the suppliers offer quantity discounts is analyzed. Quantity discounts and JIT purchasing are combined and then set up a new JIT purchasing model based on quantity discounts to take advantages of the two purchasing methods. The model considers small lot sizing and frequent deliveries policies in JIT purchasing system with variable demand and variable supply. The purpose of this study is to minimize the total relevant costs of the Manufacturer, so as to obtain the optimal number of deliveries, shipping points and shipping quantities in each shipping point. The algorithm procedure and numerical example for the model are also given.

  17. AN ENTROPIC ORDER QUANTITY MODEL WITH FUZZY HOLDING COST AND FUZZY DISPOSAL COST FOR PERISHABLE ITEMS UNDER TWO COMPONENT DEMAND AND DISCOUNTED SELLING PRICE

    Directory of Open Access Journals (Sweden)

    P.K. Tripathy

    2008-07-01

    Full Text Available A new type of replenishment policy is suggested in an entropy order quantity model for a perishable product possessing fuzzy holding cost and fuzzy disposal cost. This model represents an appropriate combination of two component demand with discounted selling price, particularly over a finite time horizon. Its main aim lies in the need for an entropic cost of the cycle time is a key feature of specific perishable product like fruits, vegetables, food stuffs, fishes etc. To handle this multiplicity of objectives in a pragmatic approach, entropic ordering quantity model with discounted selling price during pre and post deterioration of perishable items to optimize its payoff is proposed. It has been imperative to demonstrate this model by analysis, which reveals some important characteristics of discounted structure. Furthermore, numerical experiments are conducted to evaluate the difference between the crisp and fuzzy cases in EOQ and EnOQ separately. This paper explores the economy of investing in economics of lot sizing in Fuzzy EOQ, Crisp EOQ and Crisp EnOQ models. The proposed paper reveals itself as a pragmatic alternative to other approaches based on two component demand function with very sound theoretical underpinnings but with few possibilities of actually being put into practice. The results indicate that this can become a good model and can be replicated by researchers in neighbourhood of its possible extensions.

  18. The Role of Hybrid Make-to-Stock (MTS) - Make-to-Order (MTO) and Economic Order Quantity (EOQ) Inventory Control Models in Food and Beverage Processing Industry

    Science.gov (United States)

    Najhan Mohd Nagib, Ahmad; Naufal Adnan, Ahmad; Ismail, Azianti; Halim, Nurul Hayati Abdul; Syuhadah Khusaini, Nurul

    2016-11-01

    The inventory model had been utilized since the early 1900s. The implementation of the inventory management model is generally to ensure that an organisation is able to fulfil customer's demand at the lowest possible cost to improve profitability. This paper focuses on reviewing previous published papers regarding inventory control model mainly in the food and beverage processing industry. The author discusses four inventory models, which are the make-to-stock (MTS), make-to-order (MTO), economic order quantity (EOQ), and hybrid of MTS-MTO models. The issues raised by the researchers on the above techniques as well as the elements need to be considered upon selection have been discussed in this paper. The main objective of the study is to highlight the important role played by these inventory control models in the food and beverage processing industry.

  19. Statistical process control for IMRT dosimetric verification.

    Science.gov (United States)

    Breen, Stephen L; Moseley, Douglas J; Zhang, Beibei; Sharpe, Michael B

    2008-10-01

    Patient-specific measurements are typically used to validate the dosimetry of intensity-modulated radiotherapy (IMRT). To evaluate the dosimetric performance over time of our IMRT process, we have used statistical process control (SPC) concepts to analyze the measurements from 330 head and neck (H&N) treatment plans. The objectives of the present work are to: (i) Review the dosimetric measurements of a large series of consecutive head and neck treatment plans to better understand appropriate dosimetric tolerances; (ii) analyze the results with SPC to develop action levels for measured discrepancies; (iii) develop estimates for the number of measurements that are required to describe IMRT dosimetry in the clinical setting; and (iv) evaluate with SPC a new beam model in our planning system. H&N IMRT cases were planned with the PINNACLE treatment planning system versions 6.2b or 7.6c (Philips Medical Systems, Madison, WI) and treated on Varian (Palo Alto, CA) or Elekta (Crawley, UK) linacs. As part of regular quality assurance, plans were recalculated on a 20-cm-diam cylindrical phantom, and ion chamber measurements were made in high-dose volumes (the PTV with highest dose) and in low-dose volumes (spinal cord organ-at-risk, OR). Differences between the planned and measured doses were recorded as a percentage of the planned dose. Differences were stable over time. Measurements with PINNACLE3 6.2b and Varian linacs showed a mean difference of 0.6% for PTVs (n=149, range, -4.3% to 6.6%), while OR measurements showed a larger systematic discrepancy (mean 4.5%, range -4.5% to 16.3%) that was due to well-known limitations of the MLC model in the earlier version of the planning system. Measurements with PINNACLE3 7.6c and Varian linacs demonstrated a mean difference of 0.2% for PTVs (n=160, range, -3.0%, to 5.0%) and -1.0% for ORs (range -5.8% to 4.4%). The capability index (ratio of specification range to range of the data) was 1.3 for the PTV data, indicating that almost

  20. Carbon Footprint and Order Quantity in Logistics

    Directory of Open Access Journals (Sweden)

    Tian Zhiyong

    2014-05-01

    Full Text Available Purpose: Even without economic factors and government regulations, the pressure and motivation of corporation to reduce emission are still increasing. This is because the key factors for corporation to reduce emissions have become corporate social responsibility and identification of low-carbon value by consumer and society from economic trade-off and government regulations. So, the purpose of this paper is to provide quantity methods for the logistics organizations with wish of voluntary reduction and social responsibility.Design/methodology/approach: Being difference from the traditional research that takes economic value as object, this paper takes carbon footprint as object directly, order quantity as decision variable. By referring to the traditional economic order quantity model, the paper creates logistics carbon footprint model which takes transport and inventory into account. Then it solves the model by calculating the values of order quantity, carbon footprint and revenue using the method of optimization.Findings and Originality/value: By solving and comparing the two models of economic order quantity model and carbon footprint model, it gets some results, such as carbon optimization order quantity, the effects order quantity deviating from economic order quantity or carbon order quantity having on economic or carbon footprint values, which can give some meaningful insight for corporation to search out reduction opportunities by operations adjustment.Originality/value: The study takes carbon footprint as object directly and creates the corresponding quantity model. By comparing with the traditional economic order quantity model, the paper provides quantity methods and obtains some meaningful insights for the logistics organizations with wish of voluntary reduction and social responsibility to reduce emissions by operations adjustment.

  1. LIPGENE food-exchange model for alteration of dietary fat quantity and quality in free-living participants from eight European countries.

    Science.gov (United States)

    Shaw, Danielle I; Tierney, Audrey C; McCarthy, Sinead; Upritchard, Jane; Vermunt, Susan; Gulseth, Hanne L; Drevon, Christian A; Blaak, Ellen E; Saris, Wim H M; Karlström, Brita; Helal, Olfa; Defoort, Catherine; Gallego, Raquel; López-Miranda, José; Siedlecka, Dominika; Malczewska-Malec, Małgorzata; Roche, Helen M; Lovegrove, Julie A

    2009-03-01

    Controlled human intervention trials are required to confirm the hypothesis that dietary fat quality may influence insulin action. The aim was to develop a food-exchange model, suitable for use in free-living volunteers, to investigate the effects of four experimental diets distinct in fat quantity and quality: high SFA (HSFA); high MUFA (HMUFA) and two low-fat (LF) diets, one supplemented with 1.24 g EPA and DHA/d (LFn-3). A theoretical food-exchange model was developed. The average quantity of exchangeable fat was calculated as the sum of fat provided by added fats (spreads and oils), milk, cheese, biscuits, cakes, buns and pastries using data from the National Diet and Nutrition Survey of UK adults. Most of the exchangeable fat was replaced by specifically designed study foods. Also critical to the model was the use of carbohydrate exchanges to ensure the diets were isoenergetic. Volunteers from eight centres across Europe completed the dietary intervention. Results indicated that compositional targets were largely achieved with significant differences in fat quantity between the high-fat diets (39.9 (sem 0.6) and 38.9 (sem 0.51) percentage energy (%E) from fat for the HSFA and HMUFA diets respectively) and the low-fat diets (29.6 (sem 0.6) and 29.1 (sem 0.5) %E from fat for the LF and LFn-3 diets respectively) and fat quality (17.5 (sem 0.3) and 10.4 (sem 0.2) %E from SFA and 12.7 (sem 0.3) and 18.7 (sem 0.4) %E MUFA for the HSFA and HMUFA diets respectively). In conclusion, a robust, flexible food-exchange model was developed and implemented successfully in the LIPGENE dietary intervention trial.

  2. A multi-objective model for closed-loop supply chain optimization and efficient supplier selection in a competitive environment considering quantity discount policy

    Science.gov (United States)

    Jahangoshai Rezaee, Mustafa; Yousefi, Samuel; Hayati, Jamileh

    2016-11-01

    Supplier selection and allocation of optimal order quantity are two of the most important processes in closed-loop supply chain (CLSC) and reverse logistic (RL). So that providing high quality raw material is considered as a basic requirement for a manufacturer to produce popular products, as well as achieve more market shares. On the other hand, considering the existence of competitive environment, suppliers have to offer customers incentives like discounts and enhance the quality of their products in a competition with other manufacturers. Therefore, in this study, a model is presented for CLSC optimization, efficient supplier selection, as well as orders allocation considering quantity discount policy. It is modeled using multi-objective programming based on the integrated simultaneous data envelopment analysis-Nash bargaining game. In this study, maximizing profit and efficiency and minimizing defective and functions of delivery delay rate are taken into accounts. Beside supplier selection, the suggested model selects refurbishing sites, as well as determining the number of products and parts in each network's sector. The suggested model's solution is carried out using global criteria method. Furthermore, based on related studies, a numerical example is examined to validate it.

  3. Modelling water quality and quantity with the influence of inter-basin water diversion projects and cascade reservoirs in the Middle-lower Hanjiang River

    Science.gov (United States)

    Wang, Yonggui; Zhang, Wanshun; Zhao, Yanxin; Peng, Hong; Shi, Yingyuan

    2016-10-01

    The effects of inter-basin water diversion projects and cascade reservoirs are typically complex and challenging, as the uncertain temporal-spatial variation of both water quality and quantity. The purpose of this paper is to propose a coupled 1D hydrodynamic model with water-quality model to analyze the effects of current and future inter-basin water diversion projects, i.e., South-to-North Water Diversion Project (SNWD) and Yangtze-Hanjiang Water Diversion Project (YHWD), and cascade reservoirs (CRS) on water quantity and quality in the middle-lower Hanjiang River. Considering water use and pollution contribution, the middle-lower Hanjaing River basin is generalized and divided into 18 land use units with tributaries, reservoirs and water exchanges. Each unit is considered with the processes of lateral inflow, point and non-point pollution loads, irrigation return flow, and stream-aquifer exchanges in the model. The long-term time series from 1956 to 1998 of water quality and quantity with four engineering scenarios is collected. The validation of results shows that the relative errors between the simulated and observed values at certain control sections are within 5% for water levels and 20% for water quality. The water level will be decreased by 0.38-0.65 m (decreasing rate 0.44-2.68%), the annual runoff will be significantly decreased over 4 billion m3 and the water quality will be changed after the SNWD. As a compensation project, the YHWD partly offsets the negative effects of the SNWD in water flow rate, but at the same time it rises the water level and reduces the flow velocity. This, together with the effect of cascade reservoirs, leads to water quality concentration increasing and deteriorating to Grade IV of the Chinese Surface Water Quality Criteria. The water resource reduction and water quality problems in the Middle-lower Hanjiang River require attention after these projects.

  4. SU-C-204-01: A Dosimetric Investigation Into the Effects of Yttrium-90 Radioembolization On the GI Tract: In-Vivo and Histological Analysis in An Animal Model

    Energy Technology Data Exchange (ETDEWEB)

    Pasciak, A [University of Tennessee Medical Center, Knoxville, TN (United States); The University of Tennessee Graduate School of Medicine, Knoxville, TN (United States); Nodit, L; Bourgeois, A; Bradley, Y [The University of Tennessee Graduate School of Medicine, Knoxville, TN (United States); Paxton, B [Duke university medical center, Durham, NC (United States); Arepally, A [Vanderbilt University Medical Center, Nashville, TN (United States)

    2016-06-15

    Purpose: In Yttrium-90 (90Y) radioembolization, non-target embolization (NTE) to the stomach or small bowel can result in ulceration, a rare but difficult to manage clinical complication. However, dosimetric thresholds for toxicity to these tissues from radioembolization have never been evaluated in a controlled setting. We performed an analysis of the effect of 90Y radioembolization in a porcine model at different absorbed-dose endpoints. Methods: Under approval of the University of Tennessee IACUC, 6 female pigs were included in this study. Animals underwent transfemoral angiography and infusion of calibrated dosages of 90Y resin microspheres into arteries supplying part of the gastric wall. A 99mTc-MAA simulation study was performed first to determine perfused tissue volume for treatment planning along with contrast-enhanced CT. The pigs were monitored for side effects for 9 weeks, after which time they were euthanized and their upper gastrointestinal tracts were harvested for analysis. Results: 90Y radioembolization was infused resulting in average absorbed doses of between 35.5 and 91.9 Gy to the gastric wall. No animal exhibited any signs of pain or gastrointestinal distress through the duration of the study. Excised tissue showed 1–2 small (<3.0 cm2) healed or healing superficial gastric lesions in 5 out of 6 animals. Histologic analysis demonstrated that lesion location was superficial to areas of abnormally high microsphere deposition. An analysis of microsphere deposition patterns within the gastric wall indicated a high preference for submucosal deposition. Dosimetric evaluation at the luminal mucosa performed based on microsphere deposition patterns confirmed that 90Y dosimetry techniques conventionally used in hepatic dosimetry provide a reasonable estimate of absorbed dose. Conclusion: The upper gastrointestinal tract may be less sensitive to 90Y radioembolization than previously thought. Lack of charged-particle equilibrium at the luminal mucosa

  5. Oxygen nonstoichiometry, the defect equilibrium model and thermodynamic quantities of the Ruddlesden-Popper oxide Sr3Fe2O(7-δ).

    Science.gov (United States)

    Ling, Yihan; Wang, Fang; Budiman, Riyan Achmad; Nakamura, Takashi; Amezawa, Koji

    2015-03-21

    Oxygen nonstoichiometry of the Ruddlesden-Popper oxide Sr3Fe2O7-δ was measured at intermediate temperatures (773-1073 K) by coulometric titration and high temperature gravimetry. The oxygen nonstoichiometric behavior was analyzed using the defect equilibrium model with localized electrons. From the defect chemical analysis, estimated oxygen vacancy concentration at the O3 sites increases and at the O1 sites decreases with the increasing temperature. This characteristic behavior is considered to be caused by the redistribution of oxygen and vacancies between the O1 and O3 sites. The obtained thermodynamic quantities of the partial molar enthalpy of oxygen, h(O) - h°(O), and the partial molar entropy of oxygen, s(O) - s°(O), calculated from the Gibbs-Helmholtz equation are in good agreement with those from the statistical thermodynamic calculation based on the defect equilibrium model, indicating that the proposed defect equilibrium model is reasonable.

  6. Optimal pricing and lot-sizing policies for an economic production quantity model with non-instantaneous deteriorating items, permissible delay in payments, customer returns, and inflation

    DEFF Research Database (Denmark)

    Ghoreishi, Maryam; Mirzazadeh, Abolfazl; Nakhai Kamalabadi, Isa

    2014-01-01

    This article deals with an economic production quantity inventory model for non-instantaneous deteriorating items under inflationary conditions, permissible delay in payments, customer returns, and price- and time-dependent demand. The customer returns are assumed as a function of demand and price....... The effects of time value of money are studied using the Discounted Cash Flow approach. The main objective is to determine the optimal selling price, the optimal length of the production period, and the optimal length of inventory cycle simultaneously such that the present value of total profit is maximized....... An efficient algorithm is presented to find the optimal solution of the developed model. Finally, a numerical example is extracted to solve the presented inventory model using our proposed algorithm, and the effects of the customer returns, inflation, and delay in payments are also discussed....

  7. Conserved quantities in isotropic loop quantum cosmology

    CERN Document Server

    Cartin, Daniel

    2012-01-01

    We develop an action principle for those models arising from isotropic loop quantum cosmology, and show that there is a natural conserved quantity $Q$ for the discrete difference equation arising from the Hamiltonian constraint. This quantity $Q$ relates the semi-classical limit of the wavefunction at large values of the spatial volume, but opposite triad orientations. Moreover, there is a similar quantity for generic difference equations of one parameter arising from a self-adjoint operator.

  8. Application of Generalized Hukuhara derivative approach in an economic production quantity model with partial trade credit policy under fuzzy environment

    Directory of Open Access Journals (Sweden)

    Pinki Majumder

    2016-01-01

    Full Text Available In this present study, a production inventory model with partial trade credit is formulated and solved in fuzzy environment via Generalized Hukuhara derivative approach. To capture the market, a supplier offers a trade credit period to its retailers. Due to this facility, retailer also offers a partial trade credit period to his/her customer to boost the demand of the item. In practical life situation, demands are generally dependent upon time. Constant demand of an item varies time to time. In this vague situation, demands are taken as time dependent, where its constant part is taken as Left Right - type fuzzy number. In this paper, Generalized Hukuhara derivative approach is used to solve the fuzzy inventory model. Four different cases are considered by using Generalized Hukuhara-(i differentiability and Generalized Hukuhara-(ii differentiability. The objective of this paper is to find out the optimal time so as the total inventory cost is minimum. Finally the model is solved by generalized reduced gradient method. The proposed model and technique are illustrated by numerical examples. Some sensitivity analyses both in tabular and graphical forms are presented and the effects of minimum cost with respect to various inventory parameters are discussed.

  9. An inventory model of purchase quantity for fully-loaded vehicles with maximum trips in consecutive transport time

    Directory of Open Access Journals (Sweden)

    Chen Pоуu

    2013-01-01

    Full Text Available Products made overseas but sold in Taiwan are very common. Regarding the cross-border or interregional production and marketing of goods, inventory decision-makers often have to think about how to determine the amount of purchases per cycle, the number of transport vehicles, the working hours of each transport vehicle, and the delivery by ground or air transport to sales offices in order to minimize the total cost of the inventory in unit time. This model assumes that the amount of purchases for each order cycle should allow all rented vehicles to be fully loaded and the transport times to reach the upper limit within the time period. The main research findings of this study included the search for the optimal solution of the integer planning of the model and the results of sensitivity analysis.

  10. Temperature and food quantity effects on the harpacticoid copepod Nitocra spinipes: Combining in vivo bioassays with population modeling

    Science.gov (United States)

    Bui, Thuy T.; Lundström Belleza, Elin; Brinkmann, Markus; Hollert, Henner; Breitholtz, Magnus

    2017-01-01

    The harpacticoid copepod Nitocra spinipes has become a popular model species for toxicity testing over the past few decades. However, the combined influence of temperature and food shortage, two climate change-related stressors, has never been assessed in this species. Consequently, effects of three temperatures (15, 20 and 25°C) and six food regimes (between 0 and 5 × 105 algal cells/mL) on the life cycle of N. spinipes were examined in this study. Similarly to other copepod species, development times and brood sizes decreased with rising temperatures. Mortality was lowest in the 20°C temperature setup, indicating a close-by temperature optimum for this species. Decreasing food concentrations led to increased development times, higher mortality and a reduction in brood size. A sex ratio shift toward more females per male was observed for increasing temperatures, while no significant relationship with food concentration was found. Temperature and food functions for each endpoint were integrated into an existing individual-based population model for N. spinipes which in the future may serve as an extrapolation tool in environmental risk assessment. The model was able to accurately reproduce the experimental data in subsequent verification simulations. We suggest that temperature, food shortage, and potentially other climate change-related stressors should be considered in environmental risk assessment of chemicals to account for non-optimal exposure conditions that may occur in the field. Furthermore, we advocate combining in vivo bioassays with population modeling as a cost effective higher tier approach to assess such considerations. PMID:28334000

  11. An economic order quantity model with ramp type demand rate, constant deterioration rate and unit production cost

    Directory of Open Access Journals (Sweden)

    Manna Prasenjit

    2016-01-01

    Full Text Available We have developed an order level inventory system for deteriorating items with demand rate as a ramp type function of time. The finite production rate is proportional to the demand rate and the deterioration rate is independent of time. The unit production cost is inversely proportional to the demand rate. The model with no shortages case is discussed considering that: (a the demand rate is stabilized after the production stopping time and (b the demand is stabilized before the production stopping time. Optimal costs are determined for two different cases.

  12. Water Quality-Quantity Evaluation of the Ribeirão das Posses Watershed, Brazil, applying the AgES-W model.

    Science.gov (United States)

    Green, T. R.; Cruz, P. P. N. D.; Figueiredo, R. D. O.; Camargo, P. B. D.; Santos, C. P.

    2015-12-01

    Southeastern Brazil is under a period of drought that has impacted the conservation of watersheds and the management of water quality and quantity for agricultural and urban demands. In this context agro-hydrological modeling tools can generate information of water response over time in response to climate and landuse changes. A 12-km2 watershed which has suffered from anthropogenic activities is the Ribeirão das Posses watershed that is located in the extreme south of Minas Gerais State and is a headwater catchment of the Jaguari river, one of the contributing rivers of the Cantareira Reservoir Complex in the state of São Paulo. This watershed had its landscape changed over the last century from native forests to more homogeneous vegetation for pastures and small crops and some forest plantations fragments with eucalyptus. Currently, the Conservative Waters project has planted some small areas with vegetation of native species, especially where there are springs and at the top of the hills, in order to recover degraded areas and improve the hydrogeochemistry in this study basin. In this context, the AgroEcoSystem-Watershed (AgES-W) model is presented to simulate the water movement and storage in agricultural watersheds with different spatial resolutions of land areas or hydrological responses units. The objectives are to evaluate the quality and quantity of water in Ribeirão das Posses Basin using measured data, then simulate these responses in space and time to test the AgES-W model. The period chosen for research was from 2011 to 2015, because the water quality data were collected during this period. The answers that we hope to find out are: How well does the AgES-W model simulate this Brazilian watershed in the tropics? What are the future prospects of the quality and quantity of water in this basin? The results will help to guide hydrological simulations in similar tropical environments in Brazil in this and other agricultural watersheds with AgES-W.

  13. Multi-item economic production quantity model for imperfect items with multiple production setups and rework under the effect of preservation technology and learning environment

    Directory of Open Access Journals (Sweden)

    Preeti Jawla

    2016-09-01

    Full Text Available This study aims to investigate the multi-item inventory model in a production/rework system with multiple production setups. Rework can be depicted as the transformation of production rejects, failed, or non-conforming items into re-usable products of the same or lower quality during or after inspection. Rework is very valuable and profitable, especially if materials are limited in availability and also pricey. Moreover, rework can be a good contribution to a ‘green image environment’. In this paper, we establish a multi-item inventory model to determine the optimal inventory replenishment policy for the economic production quantity (EPQ model for imperfect, deteriorating items with multiple productions and rework under inflation and learning environment. In inventory modelling, Inflation plays a very important role. In one cycle, production system produces items in n production setups and one rework setup, i.e. system follows (n, 1 policy. To reduce the deterioration of products preservation technology investment is also considered in this model. Holding cost is taken as time dependent. We develop expressions for the average profit per time unit, including procurement of input materials, costs for production, rework, deterioration cost and storage of serviceable and reworkable lots. Using those expressions, the proposed model is demonstrated numerically and the sensitivity analysis is also performed to study the behaviour of the model.

  14. Quality or quantity?

    OpenAIRE

    Handa, Sudhanshu; Simler, Kenneth

    2000-01-01

    The role of school quality in determining educational outcomes has received much research attention in the United States. However, in developing countries, where a significant part of the school age population never attends school, policymakers must consider both quality and quantity when deciding how to maximize the impact of scarce investments. Acknowledging this difference in the policy environment in developing countries, this paper provides comparative estimates of the impact of quality ...

  15. Discussion of dosimetric dependencies of experimental light-induced melatonin suppression studies; Diskussion dosimetrischer Aspekte bei experimentellen Studien zur lichtinduzierten Melatoninreduktion

    Energy Technology Data Exchange (ETDEWEB)

    Weber, M.; Schulmeister, K. [ARC Seibersdorf Research (Austria). Akkreditierte Pruefstelle fuer Laser und Optische Strahlung

    2004-07-01

    Based on a literature review, dosimetric dependencies of light-induced melatonin suppression are discussed. The quantity of light used to suppress melatonin in study trials is often given in terms of illuminance at the cornea, as this is easy to measure. The use of the term illuminance for such studies is critically discussed. A more appropriate measure would be effective irradiance. In our work we present a simplified model to estimate the photobiological effective irradiance and the spot size of the retinal image. Important issues which should ideally be considered in melatonin suppression study trials are pointed out. Another aim of this work is to derive from the literature data, up to what time frame the dosedependent relationship between time and melatonin suppression is valid. An evaluation is made of the situation on the workplace with regard to light-induced melatonin suppression. (orig.)

  16. Research on Order Quantity Simulation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hong; LI Zhi-cheng

    2003-01-01

    The order quantity is often affected by various factors, so it is more valuable to research the problem of evaluating the order quantity based on a less premise. In this paper, a complicated order quantity problem is studied and an order quantity simulation system is established with the simulation software of ARENA. Finally, an example is given.

  17. Prices versus Quantities

    DEFF Research Database (Denmark)

    Hansen, Lars Gårn; Jensen, Frank

    Weitzman (2002) studies the regulation of a fishery characterised by constant marginal harvest costs and shows that price regulation performs better than quantity regulation when the regulator is uncertain about the biological reproduction function (ecological uncertainty). Here, we initially...... uncertainty. We find that the gain from eliminating compliance uncertainty may be up to 5% of gross profit while the gain from eliminating ecological uncertainty is minimal. Under landing fee regulation, the entire gain from eliminating both types of uncertainty is captured, even if the regulator’s stock...

  18. Monitoring grass nutrients and biomass as indicators of rangeland quality and quantity using random forest modelling and WorldView-2 data

    Science.gov (United States)

    Ramoelo, Abel; Cho, M. A.; Mathieu, R.; Madonsela, S.; van de Kerchove, R.; Kaszta, Z.; Wolff, E.

    2015-12-01

    Land use and climate change could have huge impacts on food security and the health of various ecosystems. Leaf nitrogen (N) and above-ground biomass are some of the key factors limiting agricultural production and ecosystem functioning. Leaf N and biomass can be used as indicators of rangeland quality and quantity. Conventional methods for assessing these vegetation parameters at landscape scale level are time consuming and tedious. Remote sensing provides a bird-eye view of the landscape, which creates an opportunity to assess these vegetation parameters over wider rangeland areas. Estimation of leaf N has been successful during peak productivity or high biomass and limited studies estimated leaf N in dry season. The estimation of above-ground biomass has been hindered by the signal saturation problems using conventional vegetation indices. The objective of this study is to monitor leaf N and above-ground biomass as an indicator of rangeland quality and quantity using WorldView-2 satellite images and random forest technique in the north-eastern part of South Africa. Series of field work to collect samples for leaf N and biomass were undertaken in March 2013, April or May 2012 (end of wet season) and July 2012 (dry season). Several conventional and red edge based vegetation indices were computed. Overall results indicate that random forest and vegetation indices explained over 89% of leaf N concentrations for grass and trees, and less than 89% for all the years of assessment. The red edge based vegetation indices were among the important variables for predicting leaf N. For the biomass, random forest model explained over 84% of biomass variation in all years, and visible bands including red edge based vegetation indices were found to be important. The study demonstrated that leaf N could be monitored using high spatial resolution with the red edge band capability, and is important for rangeland assessment and monitoring.

  19. Monte Carlo Simulation of Dosimetric Parameters for HYBRID PdI Source in Brachytherapy

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A novel brachytherapy source model, ADVANTAGE HYBRID PdI, has been designed by CIAE For treatment of cancer. In this project, the purpose of this study is to obtain the dosimetric parameters of HYBRID PdI source. The Monte Carlo simulation

  20. The ICRP protection quantities, equivalent and effective dose: their basis and application

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, J.D. [Health Protection Agency, Radiation Protection Division, Chilton, Didcot, Oxon OX11 0RQ (United Kingdom); Streffer, C. [Institute for Science and Ethics, University Duisburg-Essen, 45117 Essen (Germany)

    2007-07-01

    Equivalent and effective dose are protection quantities defined by the The International Commission on Radiological Protection (ICRP). They are frequently referred to simply as dose and may be misused. They provide a method for the summation of doses received from external sources and from intakes of radionuclides for comparison with dose limits and constraints, set to limit the risk of cancer and hereditary effects. For the assessment of internal doses, ICRP provides dose coefficients (Sv Bq{sup -1}) for the ingestion or inhalation of radionuclides by workers and members of the public, including children. Dose coefficients have also been calculated for in utero exposures following maternal intakes and for the transfer of radionuclides in breast milk. In each case, values are given of committed equivalent doses to organs and tissues and committed effective dose. Their calculation involves the use of defined biokinetic and dosimetric models, including the use of reference phantoms representing the human body. Radiation weighting factors are used as a simple representation of the different effectiveness of different radiations in causing stochastic effects at low doses. A single set of tissue weighting factors is used to take account of the contribution of individual organs and tissues to overall detriment from cancer and hereditary effects, despite age- and gender-related differences in estimates of risk and contributions to risk. The results are quantities that are not individual specific but are reference values for protection purposes, relating to doses to phantoms. The ICRP protection quantities are not intended for detailed assessments of dose and risk to individuals. They should not be used in epidemiological analyses or the assessment of the possibility of occurrence and severity of tissue reactions (deterministic effects) at higher doses. Dose coefficients are published as reference values and as such have no associated uncertainty. Assessments of

  1. Dosimetric and spectrometric neutron measurements around an annular vessel containing a plutonium nitrate fissile solution

    CERN Document Server

    Tournier, B; Medioni, R; Rich, C; Mussoni, F; Camus, L; Pichenot, G; Crovisier, P; Cutarella, D; Asselineau, B; Groetz, J E

    2002-01-01

    The new ICPR60 recommendations and the consideration of the ALARA principle have led the operators of nuclear facilities to evaluate with a higher care, the doses received by workers. The aim of this paper is to present a recent study concerning mixed field characterisation at a workplace located in a reprocessing laboratory. As a first step, neutron spectrum determination was achieved by two ways: simulation using MCNP code and experimental measurements with Bonner spheres and recoil proton counters. Neutron spectrum allowed the evaluation of dosimetric quantities. Measurements were then performed with different devices routinely used in radioprotection. The describe the measurement techniques, present the results obtained, and finally compare and discuss them.

  2. Slice-based supine to standing postured deformation for Chinese anatomical models and the dosimetric results by wide band frequency electromagnetic field exposure: morphing.

    Science.gov (United States)

    Wu, Tongning; Tan, Liwen; Shao, Qing; Li, Ying; Yang, Lei; Zhao, Chen; Xie, Yi; Zhang, Shaoxiang

    2013-04-01

    Digital human models are frequently obtained from supine-postured medical images or cadaver slices, but many applications require standing models. This paper presents the work of reconstructing standing Chinese adult anatomical models from supine postured slices. Apart from the previous studies, the deformation works on 2-D segmented slices. The surface profile of the standing posture is adjusted by population measurement data. A non-uniform texture amplification approach is applied on the 2-D slices to recover the skin contour and to redistribute the internal tissues. Internal organ shift due to postures is taken into account. The feet are modified by matrix rotation. Then, the supine and standing models are utilised for the evaluation of electromagnetic field exposure over wide band frequency and different incident directions.

  3. Thermal quantities of {sup 46}Ti

    Energy Technology Data Exchange (ETDEWEB)

    Rahmatinejad, A. [Department of Physics, Faculty of Science, University of Zanjan, Zanjan (Iran, Islamic Republic of); Razavi, R., E-mail: rrazavin@ihu.ac.ir [Physics Department, Faculty of Science, Imam Hossein Comprehensive University, Tehran (Iran, Islamic Republic of); Kakavand, T. [Department of Physics, Faculty of Science, Imam Khomeini International University, Qazvin (Iran, Islamic Republic of)

    2015-07-15

    Thermodynamic quantities of {sup 46}Ti have been calculated in the framework of the BCS model with inclusion of modified nuclear pairing gap (MPBCS) that was proposed in our previous publication. Using modified paring gap results in an S-shaped heat capacity curve at critical temperature with a smooth behavior instead of singular behavior of the same curve in the BCS calculations. In addition the thermal quantities have been extracted within the framework of a canonical ensemble according to the new experimental data on nuclear level densities measured by the Oslo group. Comparison shows a good agreement between our calculations in MPBCS and the extracted quantities in the canonical ensemble framework.

  4. Penerapan Economic Order Quantity (EOQ Model dengan Faktor Diskon yang Diintegrasikan pada ADempiere untuk Optimasi Biaya Persediaan di KUD Dau Malang

    Directory of Open Access Journals (Sweden)

    Tata Aransta Imas Puspita

    2012-09-01

    Full Text Available Persediaan merupakan salah satu aspek yang perlu diperhatikan oleh setiap perusahaan, terutama bagi perusahaan manufaktur. Hal ini dipicu adanya pengeluaran yang ditimbulkan dalam aktivitas persediaan, atau sering disebut sebagai biaya persediaan. Seperti halnya KUD Dau, Koperasi Unit Desa yang memproduksi susu pasteurisasi, yang setiap harinya koperasi ini harus melakukan proses produksi susu pasteurisasi untuk memenuhi kebutuhan pelanggannya. EOQ (Economic Order Quantity adalah salah satu perhitungan yang digunakan untuk menentukan kuantitas pesanan perusahaan. Dalam teori yang sederhana, EOQ hanya berlaku ketika permintaan untuk suatu produk (rate of demand, biaya pemesanan (ordering cost, biaya pembelian per unit (purchasing unit price adalah bernilai konstan. Tetapi sebaliknya, permasalahan persediaan pada KUD Dau terletak pada adanya potongan harga (faktor diskon yang diberikan oleh supplier atas dasar banyaknya unit yang dibeli. Oleh karena itu, perlu dilakukan modifikasi pada model EOQ untuk dapat diterapkan pada kasus seperti ini. Yang selanjutnya  diimplentasikan dengan pengembangan pada perangkat lunak ADempiere sebagai solusi komputasi untuk meminimalkan biaya persediaan (inventory cost KUD Dau pada aktivitas pengadaan selanjutnya.

  5. Evaluating the quantity of native H2 in Enceladus' plumes with the Cassini-INMS closed source data: constraints from modeling of ice grains impact in the instrument

    Science.gov (United States)

    Bouquet, A.; Brockwell, T.; Waite, J. H., Jr.; Chocron, S.; Teolis, B. D.; Perryman, R.; Walker, J. D.

    2016-12-01

    The data from the closed source of the Cassini Ion and Neutral Mass Spectrometer (INMS) at Enceladus' plumes shows a signal of H2 in significant quantities (15% mole fraction for low speed flybys). H2 would be considered a "smoking gun" for the suspected hydrothermal activity in Enceladus' ocean. However the H2 quantity varies with the speed of the flyby, which is attributed to the presence of ice grains in the plumes hitting the walls of the titanium antechamber of INMS and exposing fresh titanium that may react with water to form hydrogen. The large number of small ice grains arriving during a single INMS integration period creates a back-ground signal in addition to large grains causing punctual spikes. We have developed a surface chemistry model of the INMS, taking into account adsorption and chemisorption of species of interest to determine how much H2 is produced from the expected ice grains distribution for each flyby (given by Cassini CAPS data ). CTH simulations have been used to assess the contribution of grains of different size in terms of titanium produced. We show that the spikes in the mass 2 channel can be explained by microns-sized grains, and that smaller grains (below 500 nm) are the major contributors to reactions with titanium, accounting for most of the non-spike signal. We find that the mass 2 background signal due to titanium is strongly driven by the water available, and therefore its shape versus time can't follow the sharp rises in the data (see Figure). This makes the structures seen in flyby E18 either the product of several big grains or the observation of locally high density of H2 (jets). We will analyze the effect of grains on other mass channels and comparison to CDA data to de-termine whether the peaks can be attributed to multiple ice grains or to native H2. The work will be extended to the E17 and E14 flybys to reach a definitive assessment of the native H2 abundance in the Enceladus plume.

  6. Effects of selected low-impact-development (LID) techniques on water quality and quantity in the Ipswich River Basin, Massachusetts-Field and modeling studies

    Science.gov (United States)

    Zimmerman, Marc J.; Barbaro, Jeffrey R.; Sorenson, Jason R.; Waldron, Marcus C.

    2010-01-01

    During the months of August and September, flows in the Ipswich River, Massachusetts, dramatically decrease largely due to groundwater withdrawals needed to meet increased residential and commercial water demands. In the summer, rates of groundwater recharge are lower than during the rest of the year, and water demands are higher. From 2005 to 2008, the U.S. Geological Survey, in a cooperative funding agreement with the Massachusetts Department of Conservation and Recreation, monitored small-scale installations of low-impact-development (LID) enhancements designed to diminish the effects of storm runoff on the quantity and quality of surface water and groundwater. Funding for the studies also was contributed by the U.S. Environmental Protection Agency's Targeted Watersheds Grant Program through a financial assistance agreement with Massachusetts Department of Conservation and Recreation. The monitoring studies examined the effects of (1) replacing an impervious parking lot surface with a porous surface on groundwater quality, (2) installing rain gardens and porous pavement in a neighborhood of 3 acres on the quantity and quality of stormwater runoff, and (3) installing a 3,000-square foot (ft2) green roof on the quantity and quality of stormwater runoff. In addition, the effects of broad-scale implementation of LID techniques, reduced water withdrawals, and water-conservation measures on streamflow in large areas of the basin were simulated using the U.S. Geological Survey's Ipswich River Basin model. From June 2005 to 2007, groundwater quality was monitored at the Silver Lake town beach parking lot in Wilmington, MA, prior to and following the replacement of the conventional, impervious-asphalt surface with a porous surface consisting primarily of porous asphalt and porous pavers. Changes in the concentrations of the water-quality constituents, phosphorus, nitrogen, cadmium, chromium, copper, lead, nickel, zinc, and total petroleum hydrocarbons, were monitored

  7. SU-E-T-128: Dosimetric Evaluation of MLC Modeling in Pinnacle V9.2 for Varian TrueBeam STx

    Energy Technology Data Exchange (ETDEWEB)

    Otageri, P; Grant, E; Maricle, S; Mathews, B [CARTI, Inc., Little Rock, AR (United States)

    2014-06-01

    Purpose: To evaluate the effects of MLC modeling after commissioning the Varian TrueBeam LINAC in Pinnacle version 9.2. Methods: Stepand-shoot IMRT QAs were investigated when we observed our measured absolute dose results using ion chamber (Capintec PR-05P) were uncharacteristically low; about 4–5% compared to doses calculated by Pinnacle{sup 3} (Phillips, Madison, WI). This problem was predominant for large and highly modulated head and neck (HN) treatments. Intuitively we knew this had to be related to shortcomings in the MLC modeling in Pinnacle. Using film QA we were able to iteratively adjust the MLC parameters. We confirmed results by re-testing five failed IMRT QA patients; and ion chamber measurements were verified in Quasar anthropomorphic phantom. Results: After commissioning the LINAC in Pinnacle version 9.2, the MLC transmission for 6X, 10X and 15X were 2.0%, 1.7% and 2.0%, respectively, and additional Interleaf leakage for all three energies was 0.5%. These parameters were obtained from profiles scanned with an Edge detector (Sun Nuclear, Melbourne, FL) during machine commissioning. A Verification testing with radiographic EDR2 film (Kodak, Rochester, NY) measurement was performed by creating a closed MLC leaf pattern and analyzing using RIT software (RIT, Colorado Springs, CO). This reduced MLC transmission for 6X, 10X and 15X to 0.7%, 0.9% and 0.9%, respectively; while increasing additional Interleaf leakage for all three energies to 1.0%. Conclusion: Radiographic film measurements were used to correct MLC transmission values for step and shoot IMRT fields used in Pinnacle version 9.2. After adjusting the MLC parameters to correlate with the film QA, there was still very good agreement between the Pinnacle model and commissioning data. Using the same QA methodology, we were also able to improve the beam models for the Varian C-series linacs, Novalis-Tx, and TrueBeam M-120 linacs.

  8. Dosimetric study of a new polymer encapsulated palladium-103 seed

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, S; Vynckier, S [Cliniques Universitaires Saint-Luc, Radiotherapy and Oncology Department, Catholic University of Louvain, Brussels (Belgium)

    2005-04-07

    The use of low-energy photon emitters for brachytherapy applications, as in the treatment of prostate or ocular tumours, has increased significantly over the last few years. Several new seed models utilizing {sup 103}Pd and {sup 125}I have recently been introduced. Following the TG43U1 recommendations of the AAPM (American Association of Physicists in Medicine) (Rivard et al 2004 Med. Phys. 31 633), dose distributions around these low-energy photon emitters are characterized by the dose rate constant, the radial dose function and the anisotropy function in water. These functions and constants can be measured for each new seed in a solid phantom (i.e. solid water such as WT1) using high spatial resolution detectors such as very small thermoluminescent detectors. These experimental results in solid water must then be converted into liquid water by using Monte Carlo simulations. This paper presents the dosimetric parameters of a new palladium seed, OptiSeed{sup TM} (produced by International Brachytherapy (IBt), Seneffe, Belgium), made with a biocompatible polymeric shell and with a design that differs from the hollow titanium encapsulated seed, InterSource{sup 103}, produced by the same company. A polymer encapsulation was chosen by the company IBt in order to reduce the quantity of radioactive material needed for a given dose rate, and to improve the symmetry of the radiation field around the seed. The necessary experimental data were obtained by measurements with LiF thermoluminescent dosimeters (1 mm{sup 3}) in a solid water phantom (WT1) and then converted to values in liquid water using Monte Carlo calculations (MCNP-4C). Comparison of the results with a previous study by Reniers et al (2002 Appl. Radiat. Isot. 57 805) shows very good agreement for the dose rate constant and for the radial dose function. In addition, the results also indicate an improvement in isotropy compared to a conventional titanium encapsulated seed. The relative dose (anisotropy value

  9. Patient feature based dosimetric Pareto front prediction in esophageal cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiazhou; Zhao, Kuaike; Peng, Jiayuan; Xie, Jiang; Chen, Junchao; Zhang, Zhen; Hu, Weigang, E-mail: jackhuwg@gmail.com [Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, China and Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Jin, Xiance [The 1st Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang 325000 (China); Studenski, Matthew [Department of Radiation Oncology, University of Miami-Miller School of Medicine, Miami, Florida 33136 (United States)

    2015-02-15

    Purpose: To investigate the feasibility of the dosimetric Pareto front (PF) prediction based on patient’s anatomic and dosimetric parameters for esophageal cancer patients. Methods: Eighty esophagus patients in the authors’ institution were enrolled in this study. A total of 2928 intensity-modulated radiotherapy plans were obtained and used to generate PF for each patient. On average, each patient had 36.6 plans. The anatomic and dosimetric features were extracted from these plans. The mean lung dose (MLD), mean heart dose (MHD), spinal cord max dose, and PTV homogeneity index were recorded for each plan. Principal component analysis was used to extract overlap volume histogram (OVH) features between PTV and other organs at risk. The full dataset was separated into two parts; a training dataset and a validation dataset. The prediction outcomes were the MHD and MLD. The spearman’s rank correlation coefficient was used to evaluate the correlation between the anatomical features and dosimetric features. The stepwise multiple regression method was used to fit the PF. The cross validation method was used to evaluate the model. Results: With 1000 repetitions, the mean prediction error of the MHD was 469 cGy. The most correlated factor was the first principal components of the OVH between heart and PTV and the overlap between heart and PTV in Z-axis. The mean prediction error of the MLD was 284 cGy. The most correlated factors were the first principal components of the OVH between heart and PTV and the overlap between lung and PTV in Z-axis. Conclusions: It is feasible to use patients’ anatomic and dosimetric features to generate a predicted Pareto front. Additional samples and further studies are required improve the prediction model.

  10. Exact cosmological solutions from Hojman conservation quantities

    Energy Technology Data Exchange (ETDEWEB)

    Capozziello, Salvatore, E-mail: capozzie@na.infn.it [Dipartimento di Fisica, Università di Napoli “Federico II”, Napoli (Italy); INFN Sez. di Napoli, Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli (Italy); Roshan, Mahmood, E-mail: rowshan@alumni.ut.ac.ir [Department of Physics, Ferdowsi University of Mashhad, P.O. Box 1436, Mashhad (Iran, Islamic Republic of)

    2013-10-07

    We present a new approach to find exact solutions for cosmological models. By requiring the existence of a symmetry transformation vector for the equations of motion of the given cosmological model (without using either Lagrangian or Hamiltonian), one can find corresponding Hojman conserved quantities. With the help of these conserved quantities, the analysis of the cosmological model can be simplified. In the case of quintessence scalar–tensor models, we show that the Hojman conserved quantities exist for a wide range of V(ϕ)-potentials and allow to find exact solutions for the cosmic scale factor and the scalar field. Finally, we investigate the general cosmological behavior of solutions by adopting a phase-space view.

  11. Exact cosmological solutions from Hojman conservation quantities

    CERN Document Server

    Capozziello, Salvatore

    2013-01-01

    We present a new approach to find exact solutions for cosmological models. By requiring the existence of a symmetry transformation vector for the equations of motion of the given cosmological model (without using either Lagrangian or Hamiltonian), one can find corresponding Hojman conserved quantities. With the help of these conserved quantities, the analysis of the cosmological model can be simplified. In the case of quintessence scalar-tensor models, we show that the Hojman conserved quantities exist for a wide range of V(\\phi)-potentials and allow to find exact solutions for the cosmic scale factor and the scalar field. Finally, we investigate the general cosmological behavior of solutions by adopting a phase-space view.

  12. Effect of blood activity on dosimetric calculations for radiopharmaceuticals

    Science.gov (United States)

    Zvereva, Alexandra; Petoussi-Henss, Nina; Li, Wei Bo; Schlattl, Helmut; Oeh, Uwe; Zankl, Maria; Graner, Frank Philipp; Hoeschen, Christoph; Nekolla, Stephan G.; Parodi, Katia; Schwaiger, Markus

    2016-11-01

    The objective of this work was to investigate the influence of the definition of blood as a distinct source on organ doses, associated with the administration of a novel radiopharmaceutical for positron emission tomography-computed tomography (PET/CT) imaging—(S)-4-(3-18F-fluoropropyl)-L-glutamic acid (18F-FSPG). Personalised pharmacokinetic models were constructed based on clinical PET/CT images from five healthy volunteers and blood samples from four of them. Following an identifiability analysis of the developed compartmental models, person-specific model parameters were estimated using the commercial program SAAM II. Organ doses were calculated in accordance to the formalism promulgated by the Committee on Medical Internal Radiation Dose (MIRD) and the International Commission on Radiological Protection (ICRP) using specific absorbed fractions for photons and electrons previously derived for the ICRP reference adult computational voxel phantoms. Organ doses for two concepts were compared: source organ activities in organs parenchyma with blood as a separate source (concept-1); aggregate activities in perfused source organs without blood as a distinct source (concept-2). Aggregate activities comprise the activities of organs parenchyma and the activity in the regional blood volumes (RBV). Concept-1 resulted in notably higher absorbed doses for most organs, especially non-source organs with substantial blood contents, e.g. lungs (92% maximum difference). Consequently, effective doses increased in concept-1 compared to concept-2 by 3-10%. Not considering the blood as a distinct source region leads to an underestimation of the organ absorbed doses and effective doses. The pronounced influence of the blood even for a radiopharmaceutical with a rapid clearance from the blood, such as 18F-FSPG, suggests that blood should be introduced as a separate compartment in most compartmental pharmacokinetic models and blood should be considered as a distinct source in

  13. On tendering and bidding system development under quantity pricing model%工程量清单计价模式下招投标制度发展的探讨

    Institute of Scientific and Technical Information of China (English)

    李勇

    2009-01-01

    介绍了工程量清单计价的含义和工程量清单的分类,阐述了工程量清单计价模式下招投标活动遵循的原则及其对招投标机制的促进作用,并对工程量清单招标的相关问题进行了探讨并提出建议,以期完善工程量清单计价模式下招投标制度.%The paper introduces definition of quantity pricing and classification of quantity list, it states rules that must be follow under quantity pricing modal and it' s pushing effects to completion of tendering and bidding system, it also discusses about problems of tendering and bidding system development under quantity pricing model and proposes relative suggestion, so as to consummate tendering and bidding system under quantity pricing model.

  14. Methods, Devices and Computer Program Products Providing for Establishing a Model for Emulating a Physical Quantity Which Depends on at Least One Input Parameter, and Use Thereof

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention proposes methods, devices and computer program products. To this extent, there is defined a set X including N distinct parameter values x_i for at least one input parameter x, N being an integer greater than or equal to 1, first measured the physical quantity Pm1 for each...

  15. Monitoring grass nutrients and biomass as indicators of rangeland quality and quantity using random forest modelling and WorldView-2 data

    CSIR Research Space (South Africa)

    Ramoelo, Abel

    2015-12-01

    Full Text Available and biomass can be used as indicators of rangeland quality and quantity. Conventional methods for assessing these vegetation parameters at landscape scale level is time consuming and tedious. Remote sensing provides a bird-eye view of the landscape, which...

  16. Dosimetric characteristics of Novalis shaped beam surgery unit.

    Science.gov (United States)

    Yin, Fang-Fang; Zhu, Jingeng; Yan, Hui; Gaun, Haiqun; Hammoud, Rabih; Ryu, Samuel; Kim, Jae H

    2002-08-01

    The dosimetric characteristics of a new dedicated radiosurgical treatment unit are systematically measured in terms of its percent depth dose, beam profile, and relative scatter factor. High-resolution diode detector, mini-ion-chamber detector, and conventional Kodak XV films are used to measure dosimetric data for a range of field sizes from 6x6 mm to 100x100 mm. The effects of collimator size, micro-multileaf collimator shape, and detector type on the dosimetric data are investigated. Results indicate that, with careful design, accurate dosimetric data could be acquired using either a dedicated diode detector or a mini-ion-chamber detector, and film detector. Special attention is required when measuring dosimetric data for small field sizes such as 6x6 mm.

  17. Dosimetric adaptive IMRT driven by fiducial points

    Energy Technology Data Exchange (ETDEWEB)

    Crijns, Wouter, E-mail: wouter.crijns@uzleuven.be [Department of Oncology, Laboratory of Experimental Radiotherapy, KU Leuven, Herestraat 49, 3000 Leuven, Belgium and Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Van Herck, Hans [Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven, Belgium and Department of Electrical Engineering (ESAT) – PSI, Center for the Processing of Speech and Images, KU Leuven, 3000 Leuven (Belgium); Defraene, Gilles; Van den Bergh, Laura; Haustermans, Karin [Department of Oncology, Laboratory of Experimental Radiotherapy, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Slagmolen, Pieter [Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Department of Electrical Engineering (ESAT) – PSI, Center for the Processing of Speech and Images, KU Leuven, 3000 Leuven (Belgium); iMinds-KU Leuven Medical IT Department, KU Leuven, 3000 Leuven (Belgium); Maes, Frederik [Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Department of Electrical Engineering (ESAT) – PSI, Center for the Processing of Speech and Images, KU Leuven and iMinds, 3000 Leuven (Belgium); Van den Heuvel, Frank [Department of Oncology, Laboratory of Experimental Radiotherapy, KU Leuven, Herestraat 49, 3000 Leuven, Belgium and Department of Oncology, MRC-CR-UK Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford OX1 2JD (United Kingdom)

    2014-06-15

    Purpose: Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy have become standard treatments but are more sensitive to anatomical variations than 3D conformal techniques. To correct for inter- and intrafraction anatomical variations, fast and easy to implement methods are needed. Here, the authors propose a full dosimetric IMRT correction that finds a compromise in-between basic repositioning (the current clinical practice) and full replanning. It simplifies replanning by avoiding a recontouring step and a full dose calculation. It surpasses repositioning by updating the preoptimized fluence and monitor units (MU) using a limited number of fiducial points and a pretreatment (CB)CT. To adapt the fluence the fiducial points were projected in the beam's eye view (BEV). To adapt the MUs, point dose calculation towards the same fiducial points were performed. The proposed method is intrinsically fast and robust, and simple to understand for operators, because of the use of only four fiducial points and the beam data based point dose calculations. Methods: To perform our dosimetric adaptation, two fluence corrections in the BEV are combined with two MU correction steps along the beam's path. (1) A transformation of the fluence map such that it is realigned with the current target geometry. (2) A correction for an unintended scaling of the penumbra margin when the treatment beams scale to the current target size. (3) A correction for the target depth relative to the body contour and (4) a correction for the target distance to the source. The impact of the correction strategy and its individual components was evaluated by simulations on a virtual prostate phantom. This heterogeneous reference phantom was systematically subjected to population based prostate transformations to simulate interfraction variations. Additionally, a patient example illustrated the clinical practice. The correction strategy was evaluated using both dosimetric

  18. A Study on the Use of a Statistical Analysis Model to Monitor Air Pollution Status in an Air Quality Total Quantity Control District

    OpenAIRE

    Shu-Lung Kuo; Edward Ming-Yang Wu

    2013-01-01

    The air quality in Taiwan, at present, is determined by a pollution standard index (PSI) that is applied to areas of possible serious air pollution and Air Quality Total Quantity Control Districts (AQTQCD). Many studies, both in Taiwan and in other countries have examined the characteristics and levels of air pollution with PSI. This study uses air quality data collected from eight automatic air quality monitoring stations in an AQTQCD in central Taiwan and discusses the correlation between a...

  19. [Dosimetric evaluation of conformal radiotherapy: conformity factor].

    Science.gov (United States)

    Oozeer, R; Chauvet, B; Garcia, R; Berger, C; Felix-Faure, C; Reboul, F

    2000-01-01

    The aim of three-dimensional conformal therapy (3DCRT) is to treat the Planning Target Volume (PTV) to the prescribed dose while reducing doses to normal tissues and critical structures, in order to increase local control and reduce toxicity. The evaluation tools used for optimizing treatment techniques are three-dimensional visualization of dose distributions, dose-volume histograms, tumor control probabilities (TCP) and normal tissue complication probabilities (NTCP). These tools, however, do not fully quantify the conformity of dose distributions to the PTV. Specific tools were introduced to measure this conformity for a given dose level. We have extended those definitions to different dose levels, using a conformity index (CI). CI is based on the relative volumes of PTV and outside the PTV receiving more than a given dose. This parameter has been evaluated by a clinical study including 82 patients treated for lung cancer and 82 patients treated for prostate cancer. The CI was low for lung dosimetric studies (0.35 at the prescribed dose 66 Gy) due to build-up around the GTV and to spinal cord sparing. For prostate dosimetric studies, the CI was higher (0.57 at the prescribed dose 70 Gy). The CI has been used to compare treatment plans for lung 3DCRT (2 vs 3 beams) and prostate 3DCRT (4 vs 7 beams). The variation of CI with dose can be used to optimize dose prescription.

  20. PROGNOSYS AND ANALYSIS OF DOSIMETRIC SITUATION AFTER EMERGENCY ATMOSPHERIC RELEASE OF NPP IN UKRAINE

    Directory of Open Access Journals (Sweden)

    Iu. V. Bonchuk

    2009-01-01

    Full Text Available The system for the operative analysis of dosimetric situation after radiation emergencies at nuclear power plants in Ukraine (KADO is developed for decision making support. Emergency release in KADO is modelled as sequence of the discrete elements which are emitted after small time intervals that allows to take into account in calculations heterogeneity of distribution of pollution in a released cloud. Calculated predicted and avertable doses are the base information for justification of emergency and urgent countermeasures.

  1. Relevance of conserved quantities for data assimilation

    NARCIS (Netherlands)

    S. Dubinkina (Svetlana)

    2016-01-01

    htmlabstractIn this paper we study relevance of quantities conserved by a numerical scheme for data assimilation. We consider three Arakawa discretizations of the quasigeostrophic model that either preserve energy, or enstrophy, or both and an Ensemble Kalman Filter data assimilation method.

  2. Effect of Dosimetric Outliers on the Performance of a Commercial Knowledge-Based Planning Solution.

    Science.gov (United States)

    Delaney, Alexander R; Tol, Jim P; Dahele, Max; Cuijpers, Johan; Slotman, Ben J; Verbakel, Wilko F A R

    2016-03-01

    RapidPlan, a commercial knowledge-based planning solution, uses a model library containing the geometry and associated dosimetry of existing plans. This model predicts achievable dosimetry for prospective patients that can be used to guide plan optimization. However, it is unknown how suboptimal model plans (outliers) influence the predictions or resulting plans. We investigated the effect of, first, removing outliers from the model (cleaning it) and subsequently adding deliberate dosimetric outliers. Clinical plans from 70 head and neck cancer patients comprised the uncleaned (UC) ModelUC, from which outliers were cleaned (C) to create ModelC. The last 5 to 40 patients of ModelC were replanned with no attempt to spare the salivary glands. These substantial dosimetric outliers were reintroduced to the model in increments of 5, creating Model5 to Model40 (Model5-40). These models were used to create plans for a 10-patient evaluation group. Plans from ModelUC and ModelC, and ModelC and Model5-40 were compared on the basis of boost (B) and elective (E) target volume homogeneity indexes (HIB/HIE) and mean doses to oral cavity, composite salivary glands (compsal) and swallowing (compswal) structures. On average, outlier removal (ModelC vs ModelUC) had minimal effects on HIB/HIE (0%-0.4%) and sparing of organs at risk (mean dose difference to oral cavity and compsal/compswal were ≤0.4 Gy). Model5-10 marginally improved compsal sparing, whereas adding a larger number of outliers (Model20-40) led to deteriorations in compsal up to 3.9 Gy, on average. These increases are modest compared to the 14.9 Gy dose increases in the added outlier plans, due to the placement of optimization objectives below the inferior boundary of the dose-volume histogram-predicted range. Overall, dosimetric outlier removal from or addition of 5 to 10 outliers to a 70-patient model had marginal effects on resulting plan quality. Although the addition of >20 outliers deteriorated plan quality, the

  3. Patient-specific dosimetric endpoints based treatment plan quality control in radiotherapy.

    Science.gov (United States)

    Song, Ting; Staub, David; Chen, Mingli; Lu, Weiguo; Tian, Zhen; Jia, Xun; Li, Yongbao; Zhou, Linghong; Jiang, Steve B; Gu, Xuejun

    2015-11-07

    In intensity modulated radiotherapy (IMRT), the optimal plan for each patient is specific due to unique patient anatomy. To achieve such a plan, patient-specific dosimetric goals reflecting each patient's unique anatomy should be defined and adopted in the treatment planning procedure for plan quality control. This study is to develop such a personalized treatment plan quality control tool by predicting patient-specific dosimetric endpoints (DEs). The incorporation of patient specific DEs is realized by a multi-OAR geometry-dosimetry model, capable of predicting optimal DEs based on the individual patient's geometry. The overall quality of a treatment plan is then judged with a numerical treatment plan quality indicator and characterized as optimal or suboptimal. Taking advantage of clinically available prostate volumetric modulated arc therapy (VMAT) treatment plans, we built and evaluated our proposed plan quality control tool. Using our developed tool, six of twenty evaluated plans were identified as sub-optimal plans. After plan re-optimization, these suboptimal plans achieved better OAR dose sparing without sacrificing the PTV coverage, and the dosimetric endpoints of the re-optimized plans agreed well with the model predicted values, which validate the predictability of the proposed tool. In conclusion, the developed tool is able to accurately predict optimally achievable DEs of multiple OARs, identify suboptimal plans, and guide plan optimization. It is a useful tool for achieving patient-specific treatment plan quality control.

  4. Investigating the dosimetric and tumor control consequences of prostate seed loss and migration

    Energy Technology Data Exchange (ETDEWEB)

    Knaup, Courtney; Mavroidis, Panayiotis; Esquivel, Carlos; Stathakis, Sotirios; Swanson, Gregory; Baltas, Dimos; Papanikolaou, Nikos [Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States); Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States) and Department of Medical Radiation Physics, Karalinska Institutet and Stockholm University, Stockholm 17176 (Sweden); Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States); Department of Medical Physics and Engineering Offenbach Clinic, Offenbach 63069 (Germany) and Nuclear and Particle Physics Section, Physics Department, University of Athens (Greece); Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States)

    2012-06-15

    Purpose: Low dose-rate brachytherapy is commonly used to treat prostate cancer. However, once implanted, the seeds are vulnerable to loss and movement. The goal of this work is to investigate the dosimetric and radiobiological effects of the types of seed loss and migration commonly seen in prostate brachytherapy. Methods: Five patients were used in this study. For each patient three treatment plans were created using Iodine-125, Palladium-103, and Cesium-131 seeds. The three seeds that were closest to the urethra were identified and modeled as the seeds lost through the urethra. The three seeds closest to the exterior of prostatic capsule were identified and modeled as those lost from the prostate periphery. The seed locations and organ contours were exported from Prowess and used by in-house software to perform the dosimetric and radiobiological evaluation. Seed loss was simulated by simultaneously removing 1, 2, or 3 seeds near the urethra 0, 2, or 4 days after the implant or removing seeds near the exterior of the prostate 14, 21, or 28 days after the implant. Results: Loss of one, two or three seeds through the urethra results in a D{sub 90} reduction of 2%, 5%, and 7% loss, respectively. Due to delayed loss of peripheral seeds, the dosimetric effects are less severe than for loss through the urethra. However, while the dose reduction is modest for multiple lost seeds, the reduction in tumor control probability was minimal. Conclusions: The goal of this work was to investigate the dosimetric and radiobiological effects of the types of seed loss and migration commonly seen in prostate brachytherapy. The results presented show that loss of multiple seeds can cause a substantial reduction of D{sub 90} coverage. However, for the patients in this study the dose reduction was not seen to reduce tumor control probability.

  5. Dosimetric investigations on Mars-96 mission.

    Science.gov (United States)

    Semkova, J; Dachev, T s; Matviichuk, Y u; Koleva, R; Tomov, B; Baynov, P; Petrov, V; Nguyen, V; Siegrist, M; Chene, J; d'Uston, C; Cotin, F

    1994-10-01

    The dosimetric experiments Dose-M and Liulin as part of the more complex French-German-Bulgarian-Russian experiments for the investigation of the radiation environment for Mars-96 mission are described. The experiments will be realized with dosemeter-radiometer instruments, measuring absorbed dose in semiconductor detectors and the particle flux. Two detectors will be mounted on board the Mars-96 orbiter. Another detector will be on the guiderope of the Mars-96 Aerostate station. The scientific aims of Dose-M and Liulin experiments are: Analysis of the absorbed dose and the flux on the path and around Mars behind different shielding. Study of the shielding characteristics of the Martian atmosphere from galactic and solar cosmic rays including solar proton events. Together with the French gamma-spectrometer and the German neutron detectors the investigation of the radiation environment on the surface of Mars and in the atmosphere up to 4000 m altitude will be conducted.

  6. Thermoluminescent dosimetric properties of Descalvado sand

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M.I.; Caldas, L.V.E

    2006-07-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ({sup 60} Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  7. ARDENT to develop advanced dosimetric techniques

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    Earlier this week, the EU-supported Marie Curie training network ARDENT kicked off at a meeting held at CERN. The overall aim of the project is the development of advanced instrumentation for radiation dosimetry. The applications range from radiation measurements around particle accelerators, onboard commercial flights and in space, to the characterization of radioactive waste and medicine, where accurate dosimetry is of vital importance.   The ARDENT (Advanced Radiation Dosimetry European Network Training) project is both a research and a training programme, which aims at developing new dosimetric techniques while providing 15 Early-Stage Researchers (ESR) with state-of-the-art training. The project, coordinated by CERN, is funded by the European Union with a contribution of about 3.9 million euros over four years. The ARDENT initiative will focus on three main technologies: gas detectors, in particular Gas Electron Multipliers (GEM) and Tissue Equivalent Proportional Counters (TEPC); solid stat...

  8. Analysis of an economic order quantity and reorder point inventory ...

    African Journals Online (AJOL)

    Analysis of an economic order quantity and reorder point inventory control model for Siba ... Open Access DOWNLOAD FULL TEXT ... In addition, a cost estimate was done to compare both her current model and the recommended models.

  9. Hypergraph topological quantities for tagged social networks

    Science.gov (United States)

    Zlatić, Vinko; Ghoshal, Gourab; Caldarelli, Guido

    2009-09-01

    Recent years have witnessed the emergence of a new class of social networks, which require us to move beyond previously employed representations of complex graph structures. A notable example is that of the folksonomy, an online process where users collaboratively employ tags to resources to impart structure to an otherwise undifferentiated database. In a recent paper, we proposed a mathematical model that represents these structures as tripartite hypergraphs and defined basic topological quantities of interest. In this paper, we extend our model by defining additional quantities such as edge distributions, vertex similarity and correlations as well as clustering. We then empirically measure these quantities on two real life folksonomies, the popular online photo sharing site Flickr and the bookmarking site CiteULike. We find that these systems share similar qualitative features with the majority of complex networks that have been previously studied. We propose that the quantities and methodology described here can be used as a standard tool in measuring the structure of tagged networks.

  10. Dosimetric comparison of different radiation treatment modalities for acoustic neuromas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Wook; Chung, Weon Kuu [Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of); Shin, Dong Oh [Kyung Hee Medical Center, Seoul (Korea, Republic of); Shin, Dongho [National Cancer Center, Goyang (Korea, Republic of)

    2014-11-15

    The dosimetric differences for intensity-modulatedradiotherapy (IMRT), volumetric modulated arc therapy (VMAT), proton therapy(PROTON) and stereotactic radiosurgery (SRS) in patient with acoustic neuroma (AN) were compared by using the dose-volume histogram (DVH). In the present study, we estimated the dosimetric differences for patient with AN who received different treatment modalities. In this study, we found proton therapy is relatively effective treatment techniques than the other.

  11. Dosimetric characterization of a bi-directional micromultileaf collimator for stereotactic applications.

    Science.gov (United States)

    Bucciolini, M; Russo, S; Banci Buonamici, F; Pini, S; Silli, P

    2002-07-01

    A 6 MV photon beam from Linac SL75-5 has been collimated with a new micromultileaf device that is able to shape the field in the two orthogonal directions with four banks of leaves. This is the first clinical installation of the collimator and in this paper the dosimetric characterization of the system is reported. The dosimetric parameters required by the treatment planning system used for the dose calculation in the patient are: tissue maximum ratios, output factors, transmission and leakage of the leaves, penumbra values. Ionization chambers, silicon diode, radiographic films, and LiF thermoluminescent dosimeters have been employed for measurements of absolute dose and beam dosimetric data. Measurements with different dosimeters supply results in reasonable agreement among them and consistent with data available in literature for other models of micromultileaf collimator; that permits the use of the measured parameters for clinical applications. The discrepancies between results obtained with the different detectors (around 2%) for the analyzed parameters can be considered an indication of the accuracy that can be reached by current stereotactic dosimetry.

  12. Dosimetric parameters of palladium-103 brachytherapy source with Monte Carlo simulation

    Institute of Scientific and Technical Information of China (English)

    WANG JianHua; LIU Wei; XU XunJiang; GU JiaHui; CAI Jun; HUA ZhengDong; XU JiaQiang

    2008-01-01

    Before clinical application of a new source, the dosimetric parameters of the source should be accu-rately determined. This work is dedicated to the Monte Carlo method to calculate dosimetric parameters as recommended by the American Association of Physicists in Medicine (AAPM) TG-43 guidelines for model ADVANTAGETM palladium-103 source and, through comparison with data from another published report for the same source, presents a suggested dataset for clinical applications. From these calcula-tions, tables are presented for the radial dose function and the anisotropy function of palladium-103 brachytherapy source. The dose rate constants are found to be 0.671 (cGyh-1U-1) in liquid water and 0.673 (cGyh-1U-1) in Solid WaterTM. And the anisotropy constants in liquid water and Solid WaterTM are found to be 0.864 and 0.865 respectively. Comparison with the previous study shows that our results of dosimetric parameters are in good agreement with those measured and calculated by Meigooni et al. (2006) both in Water and Solid WaterTM.

  13. TU-D-9A-01: TG176: Dosimetric Effects of Couch Tops and Immobilization Devices

    Energy Technology Data Exchange (ETDEWEB)

    Olch, A [Childrens Hospital of LA, Los Angeles, CA (United States)

    2014-06-15

    The dosimetric impact from devices external to the patient is a complex combination of increased skin dose, reduced tumor dose, and altered dose distribution. Although small monitor unit or dose corrections are routinely made for blocking trays, ion chamber correction factors, or tissue inhomogeneities, the dose perturbation of the treatment couch top or immobilization devices are often overlooked. These devices also increase surface dose, an effect which is also often ignored or underestimated. These concerns have grown recently due to the increased use of monolithic carbon fiber couch tops which are optimal for imaging for patient position verification but cause attenuation and increased surface dose compared to the ‘tennis racket’ style couch top they often replace. Also, arc delivery techniques have replaced stationary gantry techniques which cause a greater fraction of the dose to be delivered from posterior angles. A host of immobilization devices are available and used to increase patient positioning reproducibility, and these also have attenuation and skin dose implications which are often ignored. This report of Task Group 176 serves to present a survey of published data that illustrates the magnitude of the dosimetric effects of a wide range of devices external to the patient. The report also provides methods for modeling couch tops in treatment planning systems so the physicist can accurately compute the dosimetric effects for indexed patient treatments. Both photon and proton beams are considered. A discussion on avoidance of high density structures during beam planning is also provided. An important aspect of this report are the recommendations we make to clinical physicists, treatment planning system vendors, and device vendors on how to make measurements of skin dose and attenuation, how to report these values, and for the vendors, an appeal is made to work together to provide accurate couch top models in planning systems. Learning Objectives

  14. Recognizing Prefixes in Scientific Quantities

    Science.gov (United States)

    Sokolowski, Andrzej

    2015-01-01

    Although recognizing prefixes in physical quantities is inherent for practitioners, it might not be inherent for students, who do not use prefixes in their everyday life experiences. This deficiency surfaces in AP Physics exams. For example, readers of an AP Physics exam reported "a common mistake of incorrectly converting nanometers to…

  15. Dosimetric and spectrometric neutron measurements around an annular vessel containing a plutonium nitrate fissile solution

    Energy Technology Data Exchange (ETDEWEB)

    Tournier, B.; Itie, C.; Medioni, R. E-mail: roger.medioni@ipsn.fr; Rich, C.; Mussoni, F.; Camus, L.; Pichenot, G.; Crovisier, Ph.; Cutarella, D.; Asselineau, B.; Groetz, J.E

    2002-01-01

    The new ICPR60 recommendations and the consideration of the ALARA principle have led the operators of nuclear facilities to evaluate with a higher care, the doses received by workers. The aim of this paper is to present a recent study concerning mixed field characterisation at a workplace located in a reprocessing laboratory. As a first step, neutron spectrum determination was achieved by two ways: simulation using MCNP code and experimental measurements with Bonner spheres and recoil proton counters. Neutron spectrum allowed the evaluation of dosimetric quantities. Measurements were then performed with different devices routinely used in radioprotection. The authors describe the measurement techniques, present the results obtained, and finally compare and discuss them.

  16. Dosimetric characterization of two radium sources for retrospective dosimetry studies

    Energy Technology Data Exchange (ETDEWEB)

    Candela-Juan, C., E-mail: ccanjuan@gmail.com [Radiation Oncology Department, La Fe University and Polytechnic Hospital, Valencia 46026, Spain and Department of Atomic, Molecular and Nuclear Physics, University of Valencia, Burjassot 46100 (Spain); Karlsson, M. [Division of Radiological Sciences, Department of Medical and Health Sciences, Linköping University, Linköping SE 581 85 (Sweden); Lundell, M. [Department of Medical Physics and Oncology, Karolinska University Hospital and Karolinska Institute, Stockholm SE 171 76 (Sweden); Ballester, F. [Department of Atomic, Molecular and Nuclear Physics, University of Valencia, Burjassot 46100 (Spain); Tedgren, Å. Carlsson [Division of Radiological Sciences, Department of Medical and Health Sciences, Linköping University, Linköping SE 581 85, Sweden and Swedish Radiation Safety Authority, Stockholm SE 171 16 (Sweden)

    2015-05-15

    Purpose: During the first part of the 20th century, {sup 226}Ra was the most used radionuclide for brachytherapy. Retrospective accurate dosimetry, coupled with patient follow up, is important for advancing knowledge on long-term radiation effects. The purpose of this work was to dosimetrically characterize two {sup 226}Ra sources, commonly used in Sweden during the first half of the 20th century, for retrospective dose–effect studies. Methods: An 8 mg {sup 226}Ra tube and a 10 mg {sup 226}Ra needle, used at Radiumhemmet (Karolinska University Hospital, Stockholm, Sweden), from 1925 to the 1960s, were modeled in two independent Monte Carlo (MC) radiation transport codes: GEANT4 and MCNP5. Absorbed dose and collision kerma around the two sources were obtained, from which the TG-43 parameters were derived for the secular equilibrium state. Furthermore, results from this dosimetric formalism were compared with results from a MC simulation with a superficial mould constituted by five needles inside a glass casing, placed over a water phantom, trying to mimic a typical clinical setup. Calculated absorbed doses using the TG-43 formalism were also compared with previously reported measurements and calculations based on the Sievert integral. Finally, the dose rate at large distances from a {sup 226}Ra point-like-source placed in the center of 1 m radius water sphere was calculated with GEANT4. Results: TG-43 parameters [including g{sub L}(r), F(r, θ), Λ, and s{sub K}] have been uploaded in spreadsheets as additional material, and the fitting parameters of a mathematical curve that provides the dose rate between 10 and 60 cm from the source have been provided. Results from TG-43 formalism are consistent within the treatment volume with those of a MC simulation of a typical clinical scenario. Comparisons with reported measurements made with thermoluminescent dosimeters show differences up to 13% along the transverse axis of the radium needle. It has been estimated that

  17. Quantity discrimination in female mosquitofish.

    Science.gov (United States)

    Agrillo, Christian; Dadda, Marco; Bisazza, Angelo

    2007-01-01

    The ability in animals to count and represent different numbers of objects has received a great deal of attention in the past few decades. Cumulative evidence from comparative studies on number discriminations report obvious analogies among human babies, non-human primates and birds and are consistent with the hypothesis of two distinct and widespread mechanisms, one for counting small numbers (verbal creatures studied; results are in agreement with the hypothesis of the existence of two distinct systems for quantity discrimination in vertebrates.

  18. Gamma Putty dosimetric studies in electron beam

    Science.gov (United States)

    Gloi, Aime M.

    2016-01-01

    Traditionally, lead has been used for field shaping in megavoltage electron beams in radiation therapy. In this study, we analyze the dosimetric parameters of a nontoxic, high atomic number (Z = 83), bismuth-loaded material called Gamma Putty that is malleable and can be easily molded to any desired shape. First, we placed an ionization chamber at different depths in a solid water phantom under a Gamma Putty shield of thickness (t = 0, 3, 5, 10, 15, 20, and 25 mm, respectively) and measured the ionizing radiation on the central axis (CAX) for electron beam ranging in energies from 6 to 20 MeV. Next, we investigated the relationship between the relative ionization (RI) measured at a fixed depth for several Gamma Putty shield at different cutout diameters ranging from 2 to 5 cm for various beam energies and derived an exponential fitting equation for clinical purposes. The dose profiles along the CAX show that bremsstrahlung dominates for Gamma Putty thickness >15 mm. For high-energy beams (12–20 MeV) and all Gamma Putty thicknesses up to 25 mm, RI below 5% could not be achieved due to the strong bremsstrahlung component. However, Gamma Putty is a very suitable material for reducing the transmission factor below 5% and protecting underlying normal tissues for low-energy electron beams (6–9 MeV). PMID:27651563

  19. Gamma Putty dosimetric studies in electron beam

    Directory of Open Access Journals (Sweden)

    Aime M Gloi

    2016-01-01

    Full Text Available Traditionally, lead has been used for field shaping in megavoltage electron beams in radiation therapy. In this study, we analyze the dosimetric parameters of a nontoxic, high atomic number (Z = 83, bismuth-loaded material called Gamma Putty that is malleable and can be easily molded to any desired shape. First, we placed an ionization chamber at different depths in a solid water phantom under a Gamma Putty shield of thickness (t = 0, 3, 5, 10, 15, 20, and 25 mm, respectively and measured the ionizing radiation on the central axis (CAX for electron beam ranging in energies from 6 to 20 MeV. Next, we investigated the relationship between the relative ionization (RI measured at a fixed depth for several Gamma Putty shield at different cutout diameters ranging from 2 to 5 cm for various beam energies and derived an exponential fitting equation for clinical purposes. The dose profiles along the CAX show that bremsstrahlung dominates for Gamma Putty thickness >15 mm. For high-energy beams (12-20 MeV and all Gamma Putty thicknesses up to 25 mm, RI below 5% could not be achieved due to the strong bremsstrahlung component. However, Gamma Putty is a very suitable material for reducing the transmission factor below 5% and protecting underlying normal tissues for low-energy electron beams (6-9 MeV.

  20. Comparative Dosimetric Estimates of a 25 keV Electron Micro-beam with three Monte Carlo Codes

    Energy Technology Data Exchange (ETDEWEB)

    Mainardi, Enrico; Donahue, Richard J.; Blakely, Eleanor A.

    2002-09-11

    The calculations presented compare the different performances of the three Monte Carlo codes PENELOPE-1999, MCNP-4C and PITS, for the evaluation of Dose profiles from a 25 keV electron micro-beam traversing individual cells. The overall model of a cell is a water cylinder equivalent for the three codes but with a different internal scoring geometry: hollow cylinders for PENELOPE and MCNP, whereas spheres are used for the PITS code. A cylindrical cell geometry with scoring volumes with the shape of hollow cylinders was initially selected for PENELOPE and MCNP because of its superior simulation of the actual shape and dimensions of a cell and for its improved computer-time efficiency if compared to spherical internal volumes. Some of the transfer points and energy transfer that constitute a radiation track may actually fall in the space between spheres, that would be outside the spherical scoring volume. This internal geometry, along with the PENELOPE algorithm, drastically reduced the computer time when using this code if comparing with event-by-event Monte Carlo codes like PITS. This preliminary work has been important to address dosimetric estimates at low electron energies. It demonstrates that codes like PENELOPE can be used for Dose evaluation, even with such small geometries and energies involved, which are far below the normal use for which the code was created. Further work (initiated in Summer 2002) is still needed however, to create a user-code for PENELOPE that allows uniform comparison of exact cell geometries, integral volumes and also microdosimetric scoring quantities, a field where track-structure codes like PITS, written for this purpose, are believed to be superior.

  1. Dosimetric Analysis of Radiation-induced Gastric Bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Mary, E-mail: maryfeng@umich.edu [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Normolle, Daniel [Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Pan, Charlie C. [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Dawson, Laura A. [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Amarnath, Sudha [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Ensminger, William D. [Department of Internal Medicine, Division of Hematology Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Lawrence, Theodore S.; Ten Haken, Randall K. [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States)

    2012-09-01

    Purpose: Radiation-induced gastric bleeding has been poorly understood. In this study, we described dosimetric predictors for gastric bleeding after fractionated radiation therapy. Methods and Materials: The records of 139 sequential patients treated with 3-dimensional conformal radiation therapy (3D-CRT) for intrahepatic malignancies were reviewed. Median follow-up was 7.4 months. The parameters of a Lyman normal tissue complication probability (NTCP) model for the occurrence of {>=}grade 3 gastric bleed, adjusted for cirrhosis, were fitted to the data. The principle of maximum likelihood was used to estimate parameters for NTCP models. Results: Sixteen of 116 evaluable patients (14%) developed gastric bleeds at a median time of 4.0 months (mean, 6.5 months; range, 2.1-28.3 months) following completion of RT. The median and mean maximum doses to the stomach were 61 and 63 Gy (range, 46-86 Gy), respectively, after biocorrection of each part of the 3D dose distributions to equivalent 2-Gy daily fractions. The Lyman NTCP model with parameters adjusted for cirrhosis predicted gastric bleed. Best-fit Lyman NTCP model parameters were n=0.10 and m=0.21 and with TD{sub 50} (normal) = 56 Gy and TD{sub 50} (cirrhosis) = 22 Gy. The low n value is consistent with the importance of maximum dose; a lower TD{sub 50} value for the cirrhosis patients points out their greater sensitivity. Conclusions: This study demonstrates that the Lyman NTCP model has utility for predicting gastric bleeding and that the presence of cirrhosis greatly increases this risk. These findings should facilitate the design of future clinical trials involving high-dose upper abdominal radiation.

  2. Exact solutions and conserved quantities in f( R, T) Gravity

    Science.gov (United States)

    Sharif, M.; Nawazish, Iqra

    2017-06-01

    This paper explores Noether and Noether gauge symmetries of anisotropic universe model in f( R, T) gravity. We consider two particular models of this gravity and evaluate their symmetry generators as well as associated conserved quantities. We also find exact solution by using cyclic variable and investigate its behavior via cosmological parameters. The behavior of cosmological parameters turns out to be consistent with recent observations which indicates accelerated expansion of the universe. Next we study Noether gauge symmetry and corresponding conserved quantities for both isotropic and anisotropic universe models. We conclude that symmetry generators and the associated conserved quantities appear in all cases.

  3. H2 production by ice grains impacts in the Cassini Ion and Neutral Mass Spectrometer at Enceladus: Modeling of the total amount by flyby to constrain the quantity of H2 in the plumes

    Science.gov (United States)

    Bouquet, Alexis; Brockwell, Tim; Waite, J. Hunter; Chocron, Sidney; Teolis, Ben; Perryman, Rebecca; Walker, James; Cassini-INMS

    2016-10-01

    The data from the closed source of the Cassini-Ion and Neutral Mass Spectrometer (INMS) at Enceladus' plumes shows presence of H2 but the detected quantities are dependant on spacecraft velocity. This is attributed to the presence of ice grains in the plumes: their impacts on the walls of the titanium antechamber of INMS' closed source expose/project fresh titanium that will react with water to form H2. The large number of small ice grains arriving during a single integration period of INMS creates a background signal in addition of large grains causing punctual spikes. ). This poses the question of how much of the detected hydrogen is native and how much is an artifact. Signficant quantities of native H2 could be considered as a "smoking gun" for the suspected hydrothermal activity in Enceladus' ocean as it is ultravolatile and would need to be the result of an ongoing production.A surface chemistry model of the INMS has been developed in order to determine how much H2 is produced from the expected ice grains distribution for each flyby. This model considers adsorption and chemisorption effects to follow the evolution of surface and gas phase species in the antechamber. It estimates production of titanium from results of multiple CTH simulations of impacts of ice grains on a titanium surface.Low velocity (7.5 km/s) impacts produce mostly solid titanium that causes a slow and persistent production of H2, inducing a mass 2 signal after the spacecraft has exited the plume. This persistent signal is key to the evaluation of the total quantity of titanium released, and therefore H2 produced, during the flyby.However the quasi-instant reaction of the titanium fragments with the surrounding water vapor creates an additional difficulty. An adiabatic expansion model of the cloud is used to estimate how much of the titanium is immediately reacted.We discuss how the simulation results compare to observations, both in term of background signal and in creating spikes from big

  4. Characterization of radiation beam filtration in computerized tomography equipments. Dosimetric influence; Caracterizacion de la filtracion del haz de radiacion en equipos de tomografia computarizada. Influencia dosimetrica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Tortosa, M.; Echevarne, M. [Universitat Rovira i Virgili (Spain); Calzado Cantera, A. [Universidad Complutense (Spain)

    2000-07-01

    The basic dosimetric quantities used in CT to assess doses to patient are the computed tomography dose index (CTDI) which can be determined either from measurements free-in-air or in standard head or body phantoms. CTDI values measured for different type of scanners can present high differences (up to a factor two). These differences are mainly due to differences in quality of the X ray beam as a consequence of differences in physical filtration. The filters used varied widely according to the manufacturer and model of scanner. Some scanners use a single fixed absorber, while others utilize two or more absorbers devoted specifically to anatomical areas (body or head) or different kind of examinations (pediatric,.). A good knowledge of the features of these absorbers (equivalent thickness and shape) is very useful in order to compare dose and to optimize the procedures for clinical use. however, such information is not always available and the assessment of the total filtration after installation of the scanners is seldom tackled. Dose measurements have been performed in order to determine the beam filtration and its influence on dose for a sample of seven third generation CT scanners. Measurements were conducted according to the ImPACT protocol, prepared specifically for the CT Scanner Dose Survey, in which we were participating. The investigated parameters were the half value layer and CT dose indexes (measured free-in-air and within phantoms), and an operational description of the shaping filters after selectable FOV values, as well. (Author) 32 refs.

  5. Dosimetric accuracy of a staged radiosurgery treatment

    Science.gov (United States)

    Cernica, George; de Boer, Steven F.; Diaz, Aidnag; Fenstermaker, Robert A.; Podgorsak, Matthew B.

    2005-05-01

    For large cerebral arteriovenous malformations (AVMs), the efficacy of radiosurgery is limited since the large doses necessary to produce obliteration may increase the risk of radiation necrosis to unacceptable levels. An alternative is to stage the radiosurgery procedure over multiple stages (usually two), effectively irradiating a smaller volume of the AVM nidus with a therapeutic dose during each session. The difference between coordinate systems defined by sequential stereotactic frame placements can be represented by a translation and a rotation. A unique transformation can be determined based on the coordinates of several fiducial markers fixed to the skull and imaged in each stereotactic coordinate system. Using this transformation matrix, isocentre coordinates from the first stage can be displayed in the coordinate system of subsequent stages allowing computation of a combined dose distribution covering the entire AVM. The accuracy of this approach was tested on an anthropomorphic head phantom and was verified dosimetrically. Subtle defects in the phantom were used as control points, and 2 mm diameter steel balls attached to the surface were used as fiducial markers and reference points. CT images (2 mm thick) were acquired. Using a transformation matrix developed with two frame placements, the predicted locations of control and reference points had an average error of 0.6 mm near the fiducial markers and 1.0 mm near the control points. Dose distributions in a staged treatment approach were accurately calculated using the transformation matrix. This approach is simple, fast and accurate. Errors were small and clinically acceptable for Gamma Knife radiosurgery. Accuracy can be improved by reducing the CT slice thickness.

  6. Dosimetric accuracy of a staged radiosurgery treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cernica, George [Department of Physics, State University of New York at Buffalo, Buffalo, NY 14263 (United States); Boer, Steven F de [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Diaz, Aidnag [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Fenstermaker, Robert A [Department of Neurosurgery, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Podgorsak, Matthew B [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States)

    2005-05-07

    For large cerebral arteriovenous malformations (AVMs), the efficacy of radiosurgery is limited since the large doses necessary to produce obliteration may increase the risk of radiation necrosis to unacceptable levels. An alternative is to stage the radiosurgery procedure over multiple stages (usually two), effectively irradiating a smaller volume of the AVM nidus with a therapeutic dose during each session. The difference between coordinate systems defined by sequential stereotactic frame placements can be represented by a translation and a rotation. A unique transformation can be determined based on the coordinates of several fiducial markers fixed to the skull and imaged in each stereotactic coordinate system. Using this transformation matrix, isocentre coordinates from the first stage can be displayed in the coordinate system of subsequent stages allowing computation of a combined dose distribution covering the entire AVM. The accuracy of this approach was tested on an anthropomorphic head phantom and was verified dosimetrically. Subtle defects in the phantom were used as control points, and 2 mm diameter steel balls attached to the surface were used as fiducial markers and reference points. CT images (2 mm thick) were acquired. Using a transformation matrix developed with two frame placements, the predicted locations of control and reference points had an average error of 0.6 mm near the fiducial markers and 1.0 mm near the control points. Dose distributions in a staged treatment approach were accurately calculated using the transformation matrix. This approach is simple, fast and accurate. Errors were small and clinically acceptable for Gamma Knife radiosurgery. Accuracy can be improved by reducing the CT slice thickness.

  7. 教员队伍变化对教学成果影响的预测模型%Prediction Model on Influence of Teacher Quantity on Teaching Result

    Institute of Scientific and Technical Information of China (English)

    韩维; 岳奎志; 杨帆; 史建国

    2012-01-01

    This paper builts the stock and flow diagrams about every element of impacting on teaching result with the change of teacher quantity on the basis of system dynamics, establishes the prediction model about teaching result in college, and simulates with Vensim PLE 5.9 to solve the bad influence on the teaching experience and teaching result when the teacher quantity has changed in a college. The simulation test shows that the model can make prediction on the teaching result trend and provide theoretical evidence for making plan of hiring and firing teachers with consideration of teaching result.%为解决院校教员数量波动对教学经验及教学成果的影响问题,基于系统动力学理论,构建影响教员队伍变化对教学成果影响的各元素存量流量图,建立院校教学成果预测模型,并以系统动力学软件Vensim PLE 5.9为平台进行建模仿真.运行结果表明,该模型能进行教学成果趋势的预测,可为考虑教学成果因素时教员应聘与解聘方案的制定提供理论依据.

  8. FBX aqueous chemical dosimeter for measurement of dosimetric parameters

    Energy Technology Data Exchange (ETDEWEB)

    Moussous, O., E-mail: o.moussous@crna.d [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz Fanon B.P. 399, 16000 Alger (Algeria); Medjadj, T. [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz Fanon B.P. 399, 16000 Alger (Algeria); Benguerba, M. [Faculte de Physique, Universite des Sciences et de la Technologie Houari-Boumediene USTHB, Alger (Algeria)

    2011-02-15

    We investigated the ferrous sulphate-benzoic acid-xylenol orange (FBX) aqueous chemical dosimeter for measurement of dosimetric parameters such as the output factor, backscatter factor and lateral beam profiles for different square fields sizes for {sup 60}Co {gamma}-rays. A water phantom was employed to measure these parameters. An ionization chamber (IC) was used for calibration and comparison. A comparison of the resulting measurements with an ionization chamber's measured parameters showed good agreement. We thus believe that the tissue equivalent FBX dosimetry system can measure the dosimetric parameters for {sup 60}Co with reasonable accuracy.

  9. Electromagnetic and Thermal Dosimetric Techniques in Humans and its Application

    Science.gov (United States)

    Hirata, Akimasa; Fujiwara, Osamu

    There has been increasing public concern about the adverse health effects of human exposure to radio frequency fields. Radio frequency fields are also used for medical application. This paper reviews electromagnetic and thermal computational dosimetric techniques, which has been developed by the authors. The feature of the thermal dosimetric method is that body core temperature can be computed reasonably unlike conventional method. This scheme is particularly useful for intense localized or whole-body electromagnetic wave exposure. Computational examples are shown to verify the effectiveness of the proposal.

  10. Biodistribution dosimetric study of radiopharmaceutical {sup 99mT}c Ixolaris in mice for melanoma diagnosis by molecular image and translational model for human beings; Estudo dosimetrico da biodistribuicao do radiofarmaco Ixolaris-{sup 99m}Tc em camundongos para diagnostico de melanoma atraves de imagem molecular e modelo translacional para humanos

    Energy Technology Data Exchange (ETDEWEB)

    Soriano, Sarah Canuto Silva

    2015-07-01

    The labeling of Ixolaris with {sup 99m}Tc was developed by Barboza et.al. (2013) aiming its use primarily in glioblastoma and after in melanoma diagnosis, a less common but very aggressive cancer and with high mortality rate. Preliminary tests on animals have proven its effectiveness of labeling but a dosimetric study to human clinical trials should be performed. This study aimed to: (1) determine the biokinetic model for the radiotracer {sup 99m}Tc-Ixolaris in mice by imaging dosimetry method; and (2) estimate the absorbed and effective dose resulting from the use of a new radiopharmaceutical for melanoma and metastases diagnosis in human beings, since a dosimetric study of new radiopharmaceuticals in animals is necessary to test them subsequently in humans and apply for registration in ANVISA. According to SPECT images, was found a latency period of 15 to 21 days for the development of lung metastasis in mice. Three C57BL6 mice, one control animal, and two animals with induced cell line B16-F10 murine melanoma were tested. The {sup 99m}Tc-Ixolaris radiopharmaceutical was administered intravenously in a caudal vein, and SPECT images were acquired 0.5 h, 1.5 h, 2.5 h, 3.5 h and 24 h post-administration for analysis and biodistribution quantification. The biokinetic model was determined and thus, obtained cumulative activity in order to estimate the absorbed dose in each organ. The mass and metabolic differences between mice and humans were considered and used to extrapolate the data acquired at different scales. Based on dose factors provided by the software MIRDOSE and Olinda (S factor), absorbed doses in irradiated target organs were calculated for the source organs, and finally the effective dose was estimated. The results indicate that for diagnostic exams conducted in human melanoma patients by administering approximately 25.7 MBq the estimated effective dose was 4.3 mSv. Comparing with effective doses obtained in other diagnostic techniques with {sup 99m

  11. Static quantities of the W boson in the SU_L(3) X U_X(1) model with right-handed neutrinos

    CERN Document Server

    García-Luna, J L; Toscano, J J

    2003-01-01

    The static electromagnetic properties of the $W$ boson are calculated in the $SU_L(3)\\times U_X(1)$ model with right--handed neutrinos. In the gauge sector this model contributes to the $WW\\gamma$ vertex via a complex neutral gauge boson $Y^0$ and a singly--charged gauge boson $Y^+$, called bileptons, whose mass is expected to be in the range of a few hundreds of GeV according to the current bounds from experimental data. It is found that when the mass of the bileptons is of the order of 200 GeV, the size of their contribution is similar to the one obtained in other weakly coupled theories, though the $W$ form factors decrease very quickly for heavier bileptons. When the bileptons are degenerate the size of the form factors gets considerably reduced. Due to the symmetry breaking hierarchy, in this model the bileptons are almost degenerate if they are much heavier than the $W$ boson.

  12. Dosimetric characteristics of a TLD dosemeter with extremities; Caracteristicas dosimetricas de un dosimetro TLD de extremidades

    Energy Technology Data Exchange (ETDEWEB)

    Molina P, D.; Diaz B, E.; Lien V, R. [Centro de Proteccion e Higiene de las Radiaciones, CPHR, Apdo.Postal 6195, Habana 6, CP 10600, Ciudad Habana (Cuba)

    1999-07-01

    It was designed a TLD dosemeter for the monitoring of the extremities. This one consists in a metallic ring with a circular orifice where is arranged a T L detector of LiF: Mg,Ti (Model JR1152C) 5 x 5 x 0.8 mm{sup 3} covered by a polyethylene fine layer. In this work were studied the dosimetric properties of the dosemeter for its application in the dosimetry of extremities for photonic radiation. the results obtained allow conclude that the designed dosemeter can be used for the extremities monitoring. (Author)

  13. 基于降价销售的EOQ模型下易变质商品库存分析%Analysis of Deteriorating Items Inventory under Economic Order Quantity Model Based on Price Reduction Sale

    Institute of Scientific and Technical Information of China (English)

    陈玲; 朱静

    2012-01-01

    This article has established Economic Order Quantity (EOQ) Model for price reduction sale of deteriorating items by taking demand as a constant, explains the existence of the optimal solution to the model, introduces the method for the optimal solution and provides theoretical basis for the promotion of deteriorating commodities.%建立了需求为常数的易变质商品降价促销的EOQ模型,对模型最优解的存在性进行了说明,并介绍了求最优解的方法,为易变质商品的促销提供理论依据。

  14. Dosimetric effects caused by couch tops and immobilization devices: report of AAPM Task Group 176.

    Science.gov (United States)

    Olch, Arthur J; Gerig, Lee; Li, Heng; Mihaylov, Ivaylo; Morgan, Andrew

    2014-06-01

    The dosimetric impact from devices external to the patient is a complex combination of increased skin dose, reduced tumor dose, and altered dose distribution. Although small monitor unit or dose corrections are routinely made for blocking trays, ion chamber correction factors, e.g., accounting for temperature and pressure, or tissue inhomogeneities, the dose perturbation of the treatment couch top or immobilization devices is often overlooked. These devices also increase skin dose, an effect which is also often ignored or underestimated. These concerns have grown recently due to the increased use of monolithic carbon fiber couch tops which are optimal for imaging for patient position verification but cause attenuation and increased skin dose compared to the "tennis racket" style couch top they often replace. Also, arc delivery techniques have replaced stationary gantry techniques which cause a greater fraction of the dose to be delivered from posterior angles. A host of immobilization devices are available and used to increase patient positioning reproducibility, and these also have attenuation and skin dose implications which are often ignored. This report of Task Group 176 serves to present a survey of published data that illustrates the magnitude of the dosimetric effects of a wide range of devices external to the patient. The report also provides methods for modeling couch tops in treatment planning systems so the physicist can accurately compute the dosimetric effects for indexed patient treatments. Both photon and proton beams are considered. A discussion on avoidance of high density structures during beam planning is also provided. An important aspect of this report are the recommendations the authors make to clinical physicists, treatment planning system vendors, and device vendors on how to make measurements of surface dose and attenuation and how to report these values. For the vendors, an appeal is made to work together to provide accurate couch top

  15. Dosimetric effects caused by couch tops and immobilization devices: Report of AAPM Task Group 176

    Energy Technology Data Exchange (ETDEWEB)

    Olch, Arthur J., E-mail: aolch@chla.usc.edu [Radiation Oncology Department, University of Southern California and Children' s Hospital Los Angeles, Los Angeles, California 90027 (United States); Gerig, Lee [Department of Physics, Ottawa Hospital Regional Cancer Centre, Carleton University, Ottawa, Ontario K1S 5B6, Canada and Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1N 6N5 (Canada); Li, Heng [Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, Texas 77030 (United States); Mihaylov, Ivaylo [Department of Radiation Oncology Department, University of Miami, Miami, Florida 33136 (United States); Morgan, Andrew [The Beacon Centre, Musgrove Park Hospital, Taunton TA1 5DA (United Kingdom)

    2014-06-15

    The dosimetric impact from devices external to the patient is a complex combination of increased skin dose, reduced tumor dose, and altered dose distribution. Although small monitor unit or dose corrections are routinely made for blocking trays, ion chamber correction factors, e.g., accounting for temperature and pressure, or tissue inhomogeneities, the dose perturbation of the treatment couch top or immobilization devices is often overlooked. These devices also increase skin dose, an effect which is also often ignored or underestimated. These concerns have grown recently due to the increased use of monolithic carbon fiber couch tops which are optimal for imaging for patient position verification but cause attenuation and increased skin dose compared to the “tennis racket” style couch top they often replace. Also, arc delivery techniques have replaced stationary gantry techniques which cause a greater fraction of the dose to be delivered from posterior angles. A host of immobilization devices are available and used to increase patient positioning reproducibility, and these also have attenuation and skin dose implications which are often ignored. This report of Task Group 176 serves to present a survey of published data that illustrates the magnitude of the dosimetric effects of a wide range of devices external to the patient. The report also provides methods for modeling couch tops in treatment planning systems so the physicist can accurately compute the dosimetric effects for indexed patient treatments. Both photon and proton beams are considered. A discussion on avoidance of high density structures during beam planning is also provided. An important aspect of this report are the recommendations the authors make to clinical physicists, treatment planning system vendors, and device vendors on how to make measurements of surface dose and attenuation and how to report these values. For the vendors, an appeal is made to work together to provide accurate couch top

  16. Role of next-nearest-neighbour hopping in the internal structure of the ground state and finite temperature quantities of 2D t-J model

    Indian Academy of Sciences (India)

    N S Mondal; N K Ghosh

    2010-06-01

    An exact diagonalization calculation for a small cluster in the two-dimensional t-J model has been studied to calculate two-hole correlation. Calculations reveal dominant hole–hole correlation for holes sitting on next-nearest-neighbour (NNN) sites and critical coupling occurs at $J/t = 0.8$. With the increase in negative-type NNN hopping, correlation decreases at NNN sites whereas it increases at other sites. The thermodynamic properties such as entropy and specific heat are studied as functions of temperature with various NNN hopping strength. Results show that with the inclusion of negative NNN hopping, the system becomes more ordered. A qualitative transition temperature region has been estimated. It is shown that with the increase in NNN hopping strength, c increases. Specific heat results show non-Fermi liquid-type behaviour of the system. All our calculations establish the importance of negative-type NNN hopping.

  17. Dose reader of dosimetric foil; Czytnik dawki folii dozymetrycznej

    Energy Technology Data Exchange (ETDEWEB)

    Machaj, B.; Strzalkowski, J.; Smolko, K.

    1997-12-31

    Read out the absorbance of a dosimetric foil is accomplished by two beam spectrophotometer. Such a solution makes possible the compensation of light source instabilities and ensures higher stability of the dose reader. The error of absorbance measurement caused by the instabilities does not exceed 0.0004 A. (author). 3 refs, 3 figs.

  18. Dose escalation in permanent brachytherapy for prostate cancer: dosimetric and biological considerations

    Energy Technology Data Exchange (ETDEWEB)

    Li, X Allen [Department of Radiation Oncology, University of Maryland, School of Medicine, 22 South Greene Street, Baltimore, MD 21201-1595 (United States); Wang, Jian Z [Department of Radiation Oncology, University of Maryland, School of Medicine, 22 South Greene Street, Baltimore, MD 21201-1595 (United States); Stewart, Robert D [School of Health Sciences, Purdue University, West Lafayette, IN 47907-1338 (United States); Di Biase, Steven J [Department of Radiation Oncology, University of Maryland, School of Medicine, 22 South Greene Street, Baltimore, MD 21201-1595 (United States)

    2003-09-07

    No prospective dose escalation study for prostate brachytherapy (PB) with permanent implants has been reported. In this work, we have performed a dosimetric and biological analysis to explore the implications of dose escalation in PB using {sup 125}I and {sup 103}Pd implants. The concept of equivalent uniform dose (EUD), proposed originally for external-beam radiotherapy (EBRT), is applied to low dose rate brachytherapy. For a given {sup 125}I or {sup 103}Pd PB, the EUD for tumour that corresponds to a dose distribution delivered by EBRT is calculated based on the linear quadratic model. The EUD calculation is based on the dose volume histogram (DVH) obtained retrospectively from representative actual patient data. Tumour control probabilities (TCPs) are also determined in order to compare the relative effectiveness of different dose levels. The EUD for normal tissue is computed using the Lyman model. A commercial inverse treatment planning algorithm is used to investigate the feasibility of escalating the dose to prostate with acceptable dose increases in the rectum and urethra. The dosimetric calculation is performed for five representative patients with different prostate sizes. A series of PB dose levels are considered for each patient using {sup 125}I and {sup 103}Pd seeds. It is found that the PB prescribed doses (minimum peripheral dose) that give an equivalent EBRT dose of 64.8, 70.2, 75.6 and 81 Gy with a fraction size of 1.8 Gy are 129, 139, 150 and 161 Gy for {sup 125}I and 103, 112, 122 and 132 Gy for {sup 103}Pd implants, respectively. Estimates of the EUD and TCP for a series of possible prescribed dose levels (e.g., 145, 160, 170 and 180 Gy for {sup 125}I and 125, 135, 145 and 155 for {sup 103}Pd implants) are tabulated. The EUD calculation was found to depend strongly on DVHs and radiobiological parameters. The dosimetric calculations suggest that the dose to prostate can be escalated without a substantial increase in both rectal and urethral dose

  19. Mechanical and dosimetric quality control for computer controlled radiotherapy treatment equipment.

    Science.gov (United States)

    Thompson, A V; Lam, K L; Balter, J M; McShan, D L; Martel, M K; Weaver, T A; Fraass, B A; Ten Haken, R K

    1995-05-01

    Modern computer controlled radiotherapy treatment equipment offers the possibility of delivering complex, multiple field treatments with minimal operator intervention, thus making multiple field conformal therapy practical. Conventional quality control programs are inadequate for this new technology, so new quality control procedures are needed. A reasonably fast, sensitive, and complete daily quality control program has been developed in our clinic that includes nearly automated mechanical as well as dosimetric tests. Automated delivery of these quality control fields is performed by the control system of the MM50 racetrack microtron, directed by the CCRS sequence processor [D. L. McShan and B. A. Fraass, Proceedings of the XIth International Conference on the use of computers in Radiation Therapy, 20-24 March 1994, Manchester, U.K. (North Western Medical Physics Department, Manchester, U.K., 1994), pp. 210-211], which controls the treatment process. The mechanical tests involve multiple irradiations of a single film to check the accuracy and reproducibility of the computer controlled setup of gantry and collimator angles, table orientation, collimator jaws, and multileaf collimator shape. The dosimetric tests, which involve multiple irradiations of an array of ionization chambers in a commercial dose detector (Keithly model 90100 Tracker System) rigidly attached to the head of the treatment gantry, check the output and symmetry of the treatment unit as a function of gantry and collimator angle and other parameters. For each of the dosimetric tests, readings from the five ionization chambers are automatically read out, stored, and analyzed by the computer, along with the geometric parameters of the treatment unit for that beam.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Clinical and dosimetric predictors of acute hematologic toxicity in rectal cancer patients undergoing chemoradiotherapy

    Science.gov (United States)

    Yang, T. Jonathan; Oh, Jung Hun; Apte, Aditya; Son, Christina H.; Deasy, Joseph O.; Goodman, Karyn A.

    2016-01-01

    Background and purpose To identify clinical and dosimetric factors associated with hematologic toxicity (HT) during chemoradiotherapy for rectal cancer. Materials and methods We analyzed 120 rectal cancer patients treated with neoadjuvant pelvic radiotherapy (PRT) with concurrent 5-fluorouracil-based chemotherapy. The coxal (ilium, ischium, and pubis) bone marrow (BM), sacral BM, and femoral BM were contoured and dose-volume parameters were extracted. Associations between cell count trend and clinical predictors were tested using repeated-measures analysis of variance (ANOVA) test. Associations between clinical variables, Vx (percentage volume receiving x Gy), and cell count ratio at nadir were tested using linear regression models. Results Nadirs for white blood cell count (WBC), absolute neutrophil count (ANC), and platelets (PLT) occurred in the second week of PRT and the fifth week for hemoglobin and absolute lymphocyte count (ALC). Using cell count ratio, patients treated with 3DCRT had a lower WBC ratio trend during PRT compared to patients treated with IMRT (p = 0.04), and patients ≥59 years of age had a lower hemoglobin ratio trend during PRT (p = 0.02). Using absolute cell count, patients treated with 3DCRT had lower ANC cell count trend (p = 0.03), and women had lower hemoglobin cell count trend compared to men (p = 0.03). On univariate analysis, use of 3DCRT was associated with a lower WBC ratio at nadir (p = 0.02). On multiple regression analysis using dosimetric variables, coxal BM V45 (p = 0.03) and sacral BM V45 (p = 0.03) were associated with a lower WBC and ANC ratio at nadir, respectively. Conclusions HT trends during PRT revealed distinct patterns: WBC, ANC, and PLT cell counts reach nadirs early and recover, while hemoglobin and ALC decline steadily. Patients who were treated with 3DCRT and older patients experienced lower cell count ratio trend during PRT. Dosimetric constraints using coxal BM V45 and sacral BM V45 can be considered. PMID

  1. Quantity Cognition: Numbers, Numerosity, Zero and Mathematics.

    Science.gov (United States)

    Harvey, Ben M

    2016-05-23

    Physical quantities differ from abstract numbers and mathematics, but recent results are revealing the neural representation of both: a new study demonstrates how an absence of quantity is transformed into a representation of zero as a number.

  2. Proposition of a core model for the thorium molten salt reactor (TMSR) minimizing the graphite moderator quantity in core; Proposition d'un modele de coeur pour le RSF thorium minimisant la quantite de moderateur graphite en coeur

    Energy Technology Data Exchange (ETDEWEB)

    Nuttin, A

    2004-07-01

    This work deals with the problem of fast damage of graphite in the core of TMSR. The approach consists to minimize the quantity of graphite used in the core (by an increase of the voluminal power) and then to extract and to reprocess. (O.M.)

  3. 运力受限的应急物资动态调度模型及算法%Model and algorithm of relief materials dynamic scheduling without sufficient vehicle quantity

    Institute of Scientific and Technical Information of China (English)

    王旭坪; 马超; 阮俊虎

    2013-01-01

    针对大规模突发事件下应急物资动态调度问题,把灾民的损失用物资未满足度的形式进行量化,构建以最小化灾民损失和车辆调度费用为目标的混合整数规划模型,以对运力受限情况下的救援车辆路径选择和应急物资分配进行综合决策.利用分层求解策略缩小问题的求解空间,改进基于客户点的编码方式,设计了针对此问题的遗传算法.代入实验数据得出了物资集散地不同运力下的应急物资动态调度方案,进而确定了最优运力配置量,与现实情况下的配送方案比较表明此模型和算法是有效的.%This paper focused on relief materials dynamic scheduling after large emergency.We quantified the loss of victims in terms of unmet needs,and formulated a mixed integer programming model in order to minimize victims' loss and vehicle scheduling expense.The main decisions were determining the delivery routes and allocating the relief supplies from relief distribution center (RDC) to save points without sufficient vehicle quantity.We used the hierarchical thinking to reduce solution space,improved the coding method and designed the genetic algorithm for this problem.Finally,experimental results show the dynamic scheduling scheme under different vehicle quantity,and determine the optimal vehicle quantity in RDC through comparative analysis,the validity of this model and algorithm is verified combining with realistic distribution scheme.

  4. Introductory lecture: basic quantities in model biomembranes.

    Science.gov (United States)

    Nagle, John F

    2013-01-01

    One of the many aspects of membrane biophysics dealt with in this Faraday Discussion regards the material moduli that describe energies at a supramolecular level. This introductory lecture first critically reviews differences in reported numerical values of the bending modulus K(C), which is a central property for the biologically important flexibility of membranes. It is speculated that there may be a reason that the shape analysis method tends to give larger values of K(C) than the micromechanical manipulation method or the more recent X-ray method that agree very well with each other. Another theme of membrane biophysics is the use of simulations to provide exquisite detail of structures and processes. This lecture critically reviews the application of atomic level simulations to the quantitative structure of simple single component lipid bilayers and diagnostics are introduced to evaluate simulations. Another theme of this Faraday Discussion was lateral heterogeneity in biomembranes with many different lipids. Coarse grained simulations and analytical theories promise to synergistically enhance experimental studies when their interaction parameters are tuned to agree with experimental data, such as the slopes of experimental tie lines in ternary phase diagrams. Finally, attention is called to contributions that add relevant biological molecules to bilayers and to contributions that study the exciting shape changes and different non-bilayer structures with different lipids.

  5. Maximizing Complementary Quantities by Projective Measurements

    Science.gov (United States)

    M. Souza, Leonardo A.; Bernardes, Nadja K.; Rossi, Romeu

    2017-04-01

    In this work, we study the so-called quantitative complementarity quantities. We focus in the following physical situation: two qubits ( q A and q B ) are initially in a maximally entangled state. One of them ( q B ) interacts with a N-qubit system ( R). After the interaction, projective measurements are performed on each of the qubits of R, in a basis that is chosen after independent optimization procedures: maximization of the visibility, the concurrence, and the predictability. For a specific maximization procedure, we study in detail how each of the complementary quantities behave, conditioned on the intensity of the coupling between q B and the N qubits. We show that, if the coupling is sufficiently "strong," independent of the maximization procedure, the concurrence tends to decay quickly. Interestingly enough, the behavior of the concurrence in this model is similar to the entanglement dynamics of a two qubit system subjected to a thermal reservoir, despite that we consider finite N. However, the visibility shows a different behavior: its maximization is more efficient for stronger coupling constants. Moreover, we investigate how the distinguishability, or the information stored in different parts of the system, is distributed for different couplings.

  6. Robust operation model for supply chain based on quantity flexibility contract%基于数量弹性契约的供应链鲁棒运作模型

    Institute of Scientific and Technical Information of China (English)

    李春发; 朱丽; 徐伟

    2012-01-01

    供应链中的各种不确定性因素造成供应链运作风险,进而影响供应链各成员及其整体绩效水平.利用鲁棒优化方法处理不确定性优化问题的优势及数量弹性契约机制的风险分担功能,研究包含一个制造商和一个销售商的二级供应链系统绩效优化问题,根据Stackelberg博弈理论,在考虑需求不确定条件下,建立了基于数量弹性契约的鲁棒优化模型,提出了区间性需求分布下的鲁棒运作策略,并给出了相关的算例,算例结果表明:具有数量弹性契约的供应链鲁棒运作策略能保证供应链中各成员及整体收益在一定程度上优于没有数量弹性契约时的收益,从而可以提高供应链各成员及其整体的收益.%Various uncertainties bring about supply chain risk, thereby affecting its members and the overall performance. Given the nice performance of robust optimization in handling problems with uncertainties, and the advantage of quantity flexibility contract with respect to risk-sharing mechanism, this paper studied a two-stage supply chain system containing one manufacturer and one distributer, established a robust operation model based on the quantity flexibility contract using the Stackelberg game theory, gave the robust strategies under the interval distribution of demand, and verified by an example: the robust strategies under quantity flexibility contract can ensure that the interests of each party are at least better than the profits without, therefore, to some extent improve the benefits of the overall supply chain and its members.

  7. Effects of low-impact-development (LID) practices on streamflow, runoff quantity, and runoff quality in the Ipswich River Basin, Massachusetts-A Summary of field and modeling studies

    Science.gov (United States)

    Zimmerman, Marc J.; Waldron, Marcus C.; Barbaro, Jeffrey R.; Sorenson, Jason R.

    2010-01-01

    Low-impact-development (LID) approaches are intended to create, retain, or restore natural hydrologic and water-quality conditions that may be affected by human alterations. Wide-scale implementation of LID techniques may offer the possibility of improving conditions in river basins, such as the Ipswich River Basin in Massachusetts, that have run dry during the summer because of groundwater withdrawals and drought. From 2005 to 2008, the U.S. Geological Survey, in a cooperative funding agreement with the Massachusetts Department of Conservation and Recreation, monitored small-scale installations of LID enhancements designed to diminish the effects of storm runoff on the quantity and quality of surface water and groundwater. Funding for the studies also was contributed by the U.S. Environmental Protection Agency's Targeted Watersheds Grant Program through a financial assistance agreement with Massachusetts Department of Conservation and Recreation. The monitoring studies examined the effects of * replacing an impervious parking-lot surface with a porous surface on groundwater quality, * installing rain gardens and porous pavement in a neighborhood of 3 acres on the quantity and quality of stormwater runoff, and * installing a 3,000-ft2 (square-foot) green roof on the quantity and quality of rainfall-generated roof runoff. In addition to these small-scale installations, the U.S. Geological Survey's Ipswich River Basin model was used to simulate the basin-wide effects on streamflow of several changes: broad-scale implementation of LID techniques, reduced water-supply withdrawals, and water-conservation measures. Water-supply and conservation scenarios for application in model simulations were developed with the assistance of two technical advisory committees that included representatives of State agencies responsible for water resources, the U.S. Environmental Protection Agency, the U.S. Geological Survey, water suppliers, and non-governmental organizations. From June

  8. Study of the dosimetric properties of an unflattened 6-MV photon beam by using the BEAMnrc code

    Science.gov (United States)

    Kajaria, Ankit; Sharma, Neeraj; Sharma, Shiru; Pradhan, Satyajit; Mandal, Abhijit; Aggarwal, Lalit. M.

    2016-08-01

    This study investigated the basic dosimetric properties of a Flattening-filter-free 6-MV photon beam based on the unique performance model of the Varian Clinic 600 linac operated with and without a flattening filter. Dosimetric features, including the central-axis absorbed dose, the beam profiles and the photon and electron fluences were calculated for the flattened and unflattened cases separately by using Monte Carlo simulations. We observe that the dosimetric field size and penumbra were slightly smaller for the unflattened beam, but the beam's non-flatness is unlikely to present a problem for treatments with small fields. Absolute depth dose calculations showed an increase in the dose rate by a factor of more than 2.4 for the unflattened 6-MV beam which depended on the depth. These results suggest that the removal of the filter could result in higher central-axis dose rates and hence, shorter beam delivery times for treatments. Surface doses were found to be higher for the unflattened beam due to more contamination electrons and low-energy photons being present in the beam. The total scatter factor, SCP, varies less with the field sizes, indicating that removing the filter from the beam line can reduce significantly the amount of head scatter photons and therefore, doses to normal tissues and organs.

  9. Validation of a personalized dosimetric evaluation tool (Oedipe) for targeted radiotherapy based on the Monte Carlo MCNPX code.

    Science.gov (United States)

    Chiavassa, S; Aubineau-Lanièce, I; Bitar, A; Lisbona, A; Barbet, J; Franck, D; Jourdain, J R; Bardiès, M

    2006-02-07

    Dosimetric studies are necessary for all patients treated with targeted radiotherapy. In order to attain the precision required, we have developed Oedipe, a dosimetric tool based on the MCNPX Monte Carlo code. The anatomy of each patient is considered in the form of a voxel-based geometry created using computed tomography (CT) images or magnetic resonance imaging (MRI). Oedipe enables dosimetry studies to be carried out at the voxel scale. Validation of the results obtained by comparison with existing methods is complex because there are multiple sources of variation: calculation methods (different Monte Carlo codes, point kernel), patient representations (model or specific) and geometry definitions (mathematical or voxel-based). In this paper, we validate Oedipe by taking each of these parameters into account independently. Monte Carlo methodology requires long calculation times, particularly in the case of voxel-based geometries, and this is one of the limits of personalized dosimetric methods. However, our results show that the use of voxel-based geometry as opposed to a mathematically defined geometry decreases the calculation time two-fold, due to an optimization of the MCNPX2.5e code. It is therefore possible to envisage the use of Oedipe for personalized dosimetry in the clinical context of targeted radiotherapy.

  10. Dosimetric properties of dysprosium doped calcium magnesium borate glass subjected to Co-60 gamma ray

    Energy Technology Data Exchange (ETDEWEB)

    Omar, R. S., E-mail: ratnasuffhiyanni@gmail.com; Wagiran, H., E-mail: husin@utm.my; Saeed, M. A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru (Malaysia)

    2016-01-22

    Thermoluminescence (TL) dosimetric properties of dysprosium doped calcium magnesium borate (CMB:Dy) glass are presented. This study is deemed to understand the application of calcium as the modifier in magnesium borate glass with the presence of dysprosium as the activator to be performed as TL dosimeter (TLD). The study provides fundamental knowledge of a glass system that may lead to perform new TL glass dosimetry application in future research. Calcium magnesium borate glass systems of (70-y) B{sub 2}O{sub 3} − 20 CaO – 10 MgO-(y) Dy{sub 2}O{sub 3} with 0.05  mol % ≤ y ≤ 0.7  mol % of dyprosium were prepared by melt-quenching technique. The amorphous structure and TL properties of the prepared samples were determined using powder X-ray diffraction (XRD) and TL reader; model Harshaw 4500 respectively. The samples were irradiated to Co-60 gamma source at a dose of 50 Gy. Dosimetric properties such as annealing procedure, time temperature profile (TTP) setting, optimization of Dy{sub 2}O{sub 3} concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

  11. Fluctuations of Intensive Quantities in Statistical Thermodynamics

    Directory of Open Access Journals (Sweden)

    Artur E. Ruuge

    2013-11-01

    Full Text Available In phenomenological thermodynamics, the canonical coordinates of a physical system split in pairs, with each pair consisting of an extensive quantity and an intensive one. In the present paper, the quasithermodynamic fluctuation theory of a model system of a large number of oscillators is extended to statistical thermodynamics based on the idea of perceiving the fluctuations of intensive variables as the fluctuations of specific extensive ones in a “thermodynamically dual” system. The extension is motivated by the symmetry of the problem in the context of an analogy with quantum mechanics, which is stated in terms of a generalized Pauli problem for the thermodynamic fluctuations. The doubled Boltzmann constant divided by the number of particles plays a similar role as the Planck constant.

  12. [Improved program maintenance of the CIRCIS dosimetric planning system].

    Science.gov (United States)

    Sevast'ianov, A I; Liutova, N A; Ratner, T G

    1983-03-01

    A special computer complex CIRCIS (Informatique, France) is used in the All-Union Cancer Research Center, USSR AMS, for the dosimetric planning of radiotherapy on 5 gamma-beam units and electron accelerator. Mathematical maintenance of the complex includes programs of the calculation of dose distribution for gamma-, inhibition and electron radiation but has no program of the calculation of the time of irradiation. The authors have devised and introduced into the complex such a program in the Fortran language that makes it possible to calculate within 2-3 min the time of irradiation for multifield rotation therapy using several units as a time, thus expediting the dosimetric planning for patients' irradiation.

  13. Gamma dosimetric parameters in some skeletal muscle relaxants

    Science.gov (United States)

    Manjunatha, H. C.

    2017-09-01

    We have studied the attenuation of gamma radiation of energy ranging from 84 keV to 1330 keV (^{170}Tm, ^{22} Na,^{137} Cs, and ^{60}Co) in some commonly used skeletal muscle relaxants such as tubocurarine chloride, gallamine triethiodide, pancuronium bromide, suxamethonium bromide and mephenesin. The mass attenuation coefficient is measured from the attenuation experiment. In the present work, we have also proposed the direct relation between mass attenuation coefficient (μ /ρ ) and mass energy absorption coefficient (μ _{en}/ρ ) based on the nonlinear fitting procedure. The gamma dosimetric parameters such as mass energy absorption coefficient (μ _{en}/ρ ), effective atomic number (Z_{eff}), effective electron density (N_{el}), specific {\\upgamma }-ray constant, air kerma strength and dose rate are evaluated from the measured mass attentuation coefficient. These measured gamma dosimetric parameters are compared with the theoretical values. The measured values agree with the theoretical values. The studied gamma dosimetric values for the relaxants are useful in medical physics and radiation medicine.

  14. Effective atomic numbers and electron density of dosimetric material

    Directory of Open Access Journals (Sweden)

    Kaginelli S

    2009-01-01

    Full Text Available A novel method for determination of mass attenuation coefficient of x-rays employing NaI (Tl detector system and radioactive sources is described.in this paper. A rigid geometry arrangement and gating of the spectrometer at FWHM position and selection of absorber foils are all done following detailed investigation, to minimize the effect of small angle scattering and multiple scattering on the mass attenuation coefficient, m/r, value. Firstly, for standardization purposes the mass attenuation coefficients of elemental foils such as Aluminum, Copper, Molybdenum, Tantalum and Lead are measured and then, this method is utilized for dosimetric interested material (sulfates. The experimental mass attenuation coefficient values are compared with the theoretical values to find good agreement between the theory and experiment within one to two per cent. The effective atomic numbers of the biological substitute material are calculated by sum rule and from the graph. The electron density of dosimetric material is calculated using the effective atomic number. The study has discussed in detail the attenuation coefficient, effective atomic number and electron density of dosimetric material/biological substitutes.

  15. Gamma dosimetric parameters in some skeletal muscle relaxants

    Indian Academy of Sciences (India)

    H C MANJUNATHA

    2017-09-01

    We have studied the attenuation of gamma radiation of energy ranging from 84 keV to 1330 keV $(^{170}Tm, ^{22}Na, ^{137}Cs, and ^{60}Co)$ in some commonly used skeletal muscle relaxants such as tubocurarine chloride, gallamine triethiodide, pancuronium bromide, suxamethonium bromide and mephenesin. The mass attenuation coefficient is measured from the attenuation experiment. In the present work, we have also proposed the direct relation between mass attenuation coefficient $(\\mu/\\rho)$ and mass energy absorption coefficient $(\\mu_{en}/\\rho)$ based on the nonlinear fitting procedure. The gamma dosimetric parameters such as mass energy absorption coefficient $(\\mu_{en}/\\rho)$, effective atomic number $\\rm{(Z_eff )}$, effective electron density $(N_\\rm{el})$, specific $\\gamma$-ray constant, air kerma strength and dose rate are evaluated from the measured mass attentuation coefficient. These measured gamma dosimetric parameters are compared with the theoretical values. The measured values agree with the theoretical values. The studied gamma dosimetric values for the relaxants are useful in medical physics and radiation medicine.

  16. Dosimetric effects of setup uncertainties on breast treatment delivery.

    Science.gov (United States)

    Harron, Elizabeth Christine; McCallum, Hazel Mhairi; Lambert, Elizabeth Lyn; Lee, Daniela; Lambert, Geoffrey David

    2008-01-01

    This study aimed to assess the dosimetric impact of setup errors during the delivery of radiotherapy to the breast, and use this information to make recommendations on intervention tolerances for portal imaging of breast treatments. Translational and rotational setup errors were simulated for 10 recent breast patients using an Oncentra MasterPlan treatment planning system. The effect of these errors on the breast and tumor bed target volumes receiving 95% and 107% of the prescribed dose were assessed. For the majority of patients, shifts of up to 10 mm or a 4 degrees patient rotation about the cranio-caudal axis had no significant effect on the dose distribution. Changes in dosimetry were more likely if the reference plan contained large hot or cold spots. For a typical patient, it is estimated that a shift of 5 mm in any one direction, or a 2 degrees patient rotation would not cause more than a 5% change in the target volume receiving between 95% and 107% of the prescribed dose. If combinations of errors occur, greater dosimetric changes would be expected. It is concluded that individual patient shifts of up to 5 mm or rotations about the cranio-caudal axis of 2 degrees or less are unlikely to affect dose-volume histogram parameters by an amount judged as clinically significant. Setup errors exceeding these values may cause large dosimetric changes for some patients, particularly those with larger hot or cold regions in the dose distribution, and intervention is therefore recommended.

  17. Benchmarking Dosimetric Quality Assessment of Prostate Intensity-Modulated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Senthi, Sashendra, E-mail: sasha.senthi@petermac.org [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Gill, Suki S. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Haworth, Annette; Kron, Tomas; Cramb, Jim [Department of Physical Sciences, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Rolfo, Aldo [Radiation Therapy Services, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Thomas, Jessica [Biostatistics and Clinical Trials, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Duchesne, Gillian M. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Hamilton, Christopher H.; Joon, Daryl Lim [Radiation Oncology Department, Austin Repatriation Hospital, Heidelberg, VIC (Australia); Bowden, Patrick [Radiation Oncology Department, Tattersall' s Cancer Center, East Melbourne, VIC (Australia); Foroudi, Farshad [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia)

    2012-02-01

    Purpose: To benchmark the dosimetric quality assessment of prostate intensity-modulated radiotherapy and determine whether the quality is influenced by disease or treatment factors. Patients and Methods: We retrospectively analyzed the data from 155 consecutive men treated radically for prostate cancer using intensity-modulated radiotherapy to 78 Gy between January 2007 and March 2009 across six radiotherapy treatment centers. The plan quality was determined by the measures of coverage, homogeneity, and conformity. Tumor coverage was measured using the planning target volume (PTV) receiving 95% and 100% of the prescribed dose (V{sub 95%} and V{sub 100%}, respectively) and the clinical target volume (CTV) receiving 95% and 100% of the prescribed dose. Homogeneity was measured using the sigma index of the PTV and CTV. Conformity was measured using the lesion coverage factor, healthy tissue conformity index, and the conformity number. Multivariate regression models were created to determine the relationship between these and T stage, risk status, androgen deprivation therapy use, treatment center, planning system, and treatment date. Results: The largest discriminatory measurements of coverage, homogeneity, and conformity were the PTV V{sub 95%}, PTV sigma index, and conformity number. The mean PTV V{sub 95%} was 92.5% (95% confidence interval, 91.3-93.7%). The mean PTV sigma index was 2.10 Gy (95% confidence interval, 1.90-2.20). The mean conformity number was 0.78 (95% confidence interval, 0.76-0.79). The treatment center independently influenced the coverage, homogeneity, and conformity (all p < .0001). The planning system independently influenced homogeneity (p = .038) and conformity (p = .021). The treatment date independently influenced the PTV V{sub 95%} only, with it being better at the start (p = .013). Risk status, T stage, and the use of androgen deprivation therapy did not influence any aspect of plan quality. Conclusion: Our study has benchmarked measures

  18. 两供应商单零售商的货架展示量与定价决策模型%Two Suppliers and One Retailer's Shelf-Display-Quantity and Pricing Decision Models

    Institute of Scientific and Technical Information of China (English)

    陈星

    2011-01-01

    From the point of view of the retailers, firstly, retailer's decentralized decisions with profit-maximization are analyzed. Secondly, two centralized decision models are studied for maximizing profits of the whole supply chain system and the allied channel consisting of the supplier and retailer respectively. And then, the contract of subsidy on the basis of wholesale price which is relevant with display quantity and retail price is mentioned. which obtains decentralized decisions of coordinating retailer, and achieve the result that is consistent with the decision of maximizing profits of the system.%本文从零售商的角度,首先分析了零售商自身利润最大化的分散式决策,然后分别研究了供应链系统利润最大化、供应商和零售商联盟下的渠道利润最大化的集中式决策模型.进而提出了与展示量和零售价格相关的批发价加补贴合同,得到协调零售商的分散式决策,达到与系统利润最大化决策一致的结果.

  19. Buyer-seller coordination and quantity discount pricing model in the supply-chain%供应链中的买-卖协调及数量折扣定价模型

    Institute of Scientific and Technical Information of China (English)

    韩晓军; 陈秋双

    2000-01-01

    供应链中买方与卖方之间的协调.涉及到采购、组织生产、库存管理和双方用于贸易的必不可少的通讯、交通等多个环节.研究买方、卖方如何协调以节约各个环节的费用,对于降低买卖双方的成本,提高经济效益是非常重要的.国内外学者在这方面已经做了大量的工作,本文就买方-卖方联合系统及数量折扣定价模型进行了总结和分析.%One of the three coordinations defined by operational planning in supply-chain management is the buyerseller coordination. It includes several stages ,such as purchase ,production,inventroy control,communication and transportation used to the trade. It is important for buyer and seller how toreduce the cost and improve the benefit for both sides. There is a lot of literatures on this topic. This paper makes a summary about the buyer-seller joint system and quantity discount pricing model.

  20. 36 CFR 223.220 - Quantity determination.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Quantity determination. 223.220 Section 223.220 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE SALE AND DISPOSAL OF NATIONAL FOREST SYSTEM TIMBER Special Forest Products § 223.220 Quantity determination...

  1. Rethinking Intensive Quantities via Guided Mediated Abduction

    Science.gov (United States)

    Abrahamson, Dor

    2012-01-01

    Some intensive quantities, such as slope, velocity, or likelihood, are perceptually privileged in the sense that they are experienced as holistic, irreducible sensations. However, the formal expression of these quantities uses "a/b" analytic metrics; for example, the slope of a line is the quotient of its rise and run. Thus, whereas students'…

  2. Keeping Secrets : Quantity, Quality and Consequences

    NARCIS (Netherlands)

    Frijns, T.

    2005-01-01

    Keeping Secrets deals with the consequences of an elusive yet everyday phenomenon. It addresses both the quantity and quality of secret-keeping. With respect to quantity, it presents research on the intra- and interpersonal consequences of keeping secrets from parents in adolescence. With respect t

  3. Relative TL and OSL efficiency to protons of various dosimetric materials.

    Science.gov (United States)

    Sądel, M; Bilski, P; Swakoń, J

    2014-10-01

    Thermoluminescence (TL) and optically stimulated luminescence (OSL) are the well-known phenomena used for passive methods of dose measurements. TL and OSL detectors are frequently used in the dosimetry of cosmic radiation in space and of particle radiotherapy beams. However, the relative TL/OSL efficiency, which is defined as a ratio of the emitted light intensity per unit dose for a given radiation type, to the same quantity for the reference gamma radiation is not constant and depends on radiation type and energy. In the present work several types of TL and OSL dosimetric materials, including lithium fluoride (LiF), aluminium oxide, beryllium oxide and lithium aluminate, were tested with protons. The measurements were realised exploiting the 60-MeV proton beam of the AIC-144 cyclotron in the Proton Eye Radiotherapy Facility at Institute of Nuclear Physics (IFJ PAN). The influence of proton energy on the relative efficiency and other TL/OSL characteristics of the studied detector types was presented. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Quality and quantity classification models of Fructus Amomi applying electronic nose with multiple mathematical statistics methods%中药砂仁“品与质”电子鼻判别模型的建立

    Institute of Scientific and Technical Information of China (English)

    邹慧琴; 拱健婷; 赵丽莹; 陶欧; 李佳慧; 任智宇; 闫永红

    2015-01-01

    Objective Fructus Amomi(Sharen) is derived from the dry ripe fruit of Amomum villosum Lour., A.villosum Lour. var. xanthioides T.L. Wu et Senjen and A.longiligulate T.L.Wu, which is widely utilized for its clinic effects on digestive system. However, Fructus Amomi from different species and habitats, possessing different quality, is difficult to identify. In this study, we aim to develop a simple, rapid and reliable method for authentication of Fructus Amomi. Methods Twenty-five batches of samples of Fructus Amomi were collected and electronic nose was introduced into analyzing their odor with multiple mathematical statistics methods. Naïve bayes network (NBN), radical basis function (RBF) and random forest (RF) were applied to establish different classifiers while BestFirst+CfsSubsetEval (BC) was used to screen the attributes for searching sensor array with higher contributions. Results Firstly, after attribute-screening via BC, the established discriminative models via NBN, RBF and RF could successfully identify genuine and non-genuine samples, presenting correct judging ratios of 78% and 84% through ten-fold cross validation and external test set validation, respectively. Besides, quantity predictive models were constructed as well. In case of content of bornyl acetate, one of the effective components in Fructus Amomi, values were higher than 3.5 mg/g and lower than 1.8 mg/g with sensor response of 0.04 and 0.03, respectively. Conclusion In this paper, quality discriminative model and quantity predictive model of Fructus Amomi were established via electronic nose and multiple mathematical statistics methods. It indicates that electronic nose could be a promising method for quality evaluation of Chinese material medica.%目的:建立一种快速、有效识别中药砂仁品质的科学评价方法。方法引入电子鼻建立中药砂仁的气味指纹图谱,以不同品种、不同产地的25批砂仁样品为研究对象,采

  5. Neutron dosimetric measurements in shuttle and MIR.

    Science.gov (United States)

    Reitz, G

    2001-06-01

    Detector packages consisting of thermoluminescence detectors (TLD), nuclear emulsions and plastic track detectors were exposed at identical positions inside MIR space station and on shuttle flights inside Spacelab and Spacehab during different phases of the solar cycle. The objectives of the investigations are to provide data on charge and energy spectra of heavy ions, and the contribution of events with low-energy deposit (protons, electrons, gamma, etc.) to the dose, as well as the contribution of secondaries, such as nuclear disintegration stars and neutrons. For neutron dosimetry 6LiF (TLD600) and 7LiF (TLD700) chips were used both of which have almost the same response to gamma rays but different response to neutrons. Neutrons in space are produced mainly in evaporation and knock-on processes with energies mainly of 1-10 MeV and up to several 100 MeV, respectively. The energy spectrum undergoes continuous changes toward greater depth in the attenuating material until an equilibrium is reached. In equilibrium, the spectrum is a wide continuum extending down to thermal energies to which the 6LiF is sensitive. Based on the difference of absorbed doses in the 6LiF and 7LiF chips, thermal neutron fluxes from 1 to 2.3 cm-2 s-1 are calculated using the assumption that the maximum induced dose in TLD600 for 1 neutron cm-2 is 1.6 x 10(-10) Gy (Horowitz and Freeman, Nucl. Instr. and Meth. 157 (1978) 393). It is assumed that the flux of high-energy neutrons is at least of that quantity. Tissue doses were calculated taking as a mean ambient absorbed dose per neutron 6 x10(-12) Gy cm2 (for a10 MeV neutron). The neutron equivalent doses for the above-mentioned fluxes are 52 micro Gy d-1 and 120 micro Gy d-1. In recent experiments, a personal neutron dosimeter was integrated into the dosimeter packages. First results of this dosimeter which is based on nuclear track detectors with converter foils are reported. For future measurements, a scintillator counter with

  6. On the Hojman conservation quantities in Cosmology

    Science.gov (United States)

    Paliathanasis, A.; Leach, P. G. L.; Capozziello, S.

    2016-04-01

    We discuss the application of the Hojman's Symmetry Approach for the determination of conservation laws in Cosmology, which has been recently applied by various authors in different cosmological models. We show that Hojman's method for regular Hamiltonian systems, where the Hamiltonian function is one of the involved equations of the system, is equivalent to the application of Noether's Theorem for generalized transformations. That means that for minimally-coupled scalar field cosmology or other modified theories which are conformally related with scalar-field cosmology, like f (R) gravity, the application of Hojman's method provide us with the same results with that of Noether's Theorem. Moreover we study the special Ansatz. ϕ (t) = ϕ (a (t)) , which has been introduced for a minimally-coupled scalar field, and we study the Lie and Noether point symmetries for the reduced equation. We show that under this Ansatz, the unknown function of the model cannot be constrained by the requirement of the existence of a conservation law and that the Hojman conservation quantity which arises for the reduced equation is nothing more than the functional form of Noetherian conservation laws for the free particle. On the other hand, for f (T) teleparallel gravity, it is not the existence of Hojman's conservation laws which provide us with the special function form of f (T) functions, but the requirement that the reduced second-order differential equation admits a Jacobi Last multiplier, while the new conservation law is nothing else that the Hamiltonian function of the reduced equation.

  7. Correlation between dosimetric effect and intrafraction motion during prostate treatments delivered with helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Langen, Katja M; Ngwa, Wilfred; Willoughby, Twyla R; Chauhan, Bhavin; Meeks, Sanford L; Kupelian, Patrick A [Department of Radiation Oncology, M. D. Anderson Cancer Center Orlando, 1400 South Orange Av., Orlando, FL 32806 (United States); Lu Weiguo; Olivera, Gustavo [TomoTherapy, Inc., 1240 Deming Way, Madison, WI 53717 (United States)], E-mail: katja.langen@orhs.org

    2008-12-21

    The dosimetric impact of intrafraction prostate motion was investigated for helical tomotherapy treatments. Measured motion tracks were used to calculate the dosimetric impact on delivered target dose distributions. A dynamic dose calculation engine was developed to facilitate this evaluation. It was found that the D{sub 95%} (minimum dose to 95% of the volume) changes in the prostate were well correlated with D{sub 95%} changes in the PTV. This means that the dosimetric impact of intrafraction motion is not restricted to the periphery of the target. The amount of motion was not well correlated with the dosimetric impact (measured in target D{sub 95%} changes) of motion. The relationship between motion and its dosimetric impact is complex and depends on the timing and direction of the movement. These findings have implications for motion management techniques. It appears that the use of target margins is not an effective strategy to protect the prostate from the effects of observed intrafraction motion. The complex relationship between motion and its dosimetric effect renders simple threshold-based intervention schemes inefficient. Monitoring of actual prostate motion would allow the documentation of the dosimetric impact and implementation of corrective action if needed. However, when motion management techniques are evaluated, it should be kept in mind that the dosimetric impact of observed prostate motion is small for the majority of fractions.

  8. Dosimetric comparison of intensity modulated radiosurgery with dynamic conformal arc radiosurgery for small cranial lesions

    Directory of Open Access Journals (Sweden)

    Juan F Calvo-Ortega

    2016-01-01

    Conclusions: We have shown that IMRS provides the dosimetric advantages compared with DCARS. Based on the dosimetric findings in this study, fixed gantry IMRS technique can be adopted as a standard procedure for cranial SRS when micro-MLC technology is not available on the linear accelerator.

  9. Dosimetric characterization of the M-15 high-dose-rate Iridium-192 brachytherapy source using the AAPM and ESTRO formalism.

    Science.gov (United States)

    Ho Than, Minh-Tri; Munro Iii, John J; Medich, David C

    2015-05-08

    The Source Production & Equipment Co. (SPEC) model M-15 is a new Iridium-192 brachytherapy source model intended for use as a temporary high-dose-rate (HDR) brachytherapy source for the Nucletron microSelectron Classic afterloading system. The purpose of this study is to characterize this HDR source for clinical application by obtaining a complete set of Monte Carlo calculated dosimetric parameters for the M-15, as recommended by AAPM and ESTRO, for isotopes with average energies greater than 50 keV. This was accomplished by using the MCNP6 Monte Carlo code to simulate the resulting source dosimetry at various points within a pseudoinfinite water phantom. These dosimetric values next were converted into the AAPM and ESTRO dosimetry parameters and the respective statistical uncertainty in each parameter also calculated and presented. The M-15 source was modeled in an MCNP6 Monte Carlo environment using the physical source specifications provided by the manufacturer. Iridium-192 photons were uniformly generated inside the iridium core of the model M-15 with photon and secondary electron transport replicated using photoatomic cross-sectional tables supplied with MCNP6. Simulations were performed for both water and air/vacuum computer models with a total of 4 × 109 sources photon history for each simulation and the in-air photon spectrum filtered to remove low-energy photons belowδ = 10 keV. Dosimetric data, including D·(r,θ), gL(r), F(r,θ), φan(r), and φ-an, and their statistical uncertainty were calculated from the output of an MCNP model consisting of an M-15 source placed at the center of a spherical water phantom of 100 cm diameter. The air kerma strength in free space, SK, and dose rate constant, Λ, also was computed from a MCNP model with M-15 Iridium-192 source, was centered at the origin of an evacuated phantom in which a critical volume containing air at STP was added 100 cm from the source center. The reference dose rate, D·(r0,θ0) ≡ D· (1cm

  10. Evaluation of dosimetric characteristics of graphene oxide/PVC nanocomposite for gamma radiation applications

    Energy Technology Data Exchange (ETDEWEB)

    Feizi, Shahzad; Malekie, Shahryar; Ziaie, Farhood [Nuclear Science and Technology Research Institute (NSTRI), Karaj (Iran, Islamic Republic of). Radiation Application Research School; Rahighi, Reza; Tayyebi, Ahmad [Univ. of Technology, Tehran (Iran, Islamic Republic of). Dept. of Physics

    2017-04-01

    Graphene oxide-polyvinyl chloride composite was prepared using tetrahydrofuran solvent-assisted dispersion of characterized nano flakes of graphene oxide in polymer matrix. Electrical percolation threshold of GO/PVC nanocomposite was determined via a finite element simulation method with a 2D model and compared with experimental results. A conductive cell with two silver coated walls was designed and fabricated for exploring dosimetric properties of the composite. Some characteristics of the new nanocomposite such as linearity of dose response, repeatability, sensitivity and angular dependence are investigated. According to 2D proposed method, obtained data associated to electrical conductivity of the GO/polymer composite for PVC matrix plotted in different GO weight percentages and had good compatibility (validity) with experimental data. The dose response is linear in the 17-51 mGy dose range and it can be introduced for gamma radiation dosimetry in diagnostic activities.

  11. Quality, Quantity, and Age: The Careers of Ten Distinguished Psychologists.

    Science.gov (United States)

    Simonton, Dean Keith

    1985-01-01

    The longitudinal relationship between quality and quantity of productive output is examined over the careers of 10 recipients of the Distinguished Scientific Contributions Award using four alternative models (expertise-acquisition, youthful-enthusiasm, peak-age, and constant-probability-of-success). The results endorsed the…

  12. CURRENT STATUS OF INDIVIDUAL DOSIMETRIC MONITORING IN UKRAINE.

    Science.gov (United States)

    Chumak, V; Deniachenko, N; Makarovska, O; Mihailescu, L-C; Prykhodko, A; Voloskyi, V; Vanhavere, F

    2016-09-01

    About 50 000 workers are being occupationally exposed to radiation in Ukraine. Individual dosimetric monitoring (IDM) is provided by 77 dosimetry services and laboratories of very different scale with a number of monitored workers ranging from several persons to ∼9000. In the present work, the current status of personal dosimetry in Ukraine was studied. The First National Intercomparison (FNI) of the IDM labs was accompanied by a survey of the laboratory operation in terms of coverage, types of dosimetry provided, instrumentation and methodologies used, metrological support, data recording, etc. Totally, 34 laboratories responded to the FNI call, and 18 services with 19 different personal dosimetry systems took part in the intercomparison exercise providing 24 dosimeters each for blind irradiation to photons of 6 different qualities (ISO N-series X-rays, S-Cs and S-Co sources) in a dose range of 5-60 mSv. Performance of the dosimetry labs was evaluated according to ISO 14146 criteria of matching trumpet curves with H0 = 0.2 mSv. The test revealed that 8 of the 19 systems meet ISO 14146 criteria in full, 5 other labs show marginal performance and 6 laboratories demonstrated catastrophic quality of dosimetric results. Altogether, 18 participating labs provide dosimetric monitoring to 37 477 workers (about three-fourths of all occupationally exposed workers), usually on monthly (nuclear industry) or quarterly (rest of applications) basis. Of this number, 20 664 persons (55 %) receive completely adequate individual monitoring, and the number of personnel receiving IDM of inadequate quality counts 3054 persons.

  13. Study of the thermoluminescence dosimetric properties of window glass

    Science.gov (United States)

    Engin, Birol; Aydaş, Canan; Demirtaş, Hayrünnisa

    2010-01-01

    This paper presents the main thermoluminescence (TL) dosimetric characteristics of commercial Turkish transparent window glass. The structure of the glow curves, including the number of peaks, was found to be dose-dependent. A low-temperature glow peak that at 160 °C shifts to higher temperatures was also observed with increasing storage time at room temperature. This result suggests that this TL glow peak is actually made up of two or more overlapping peaks. These we have attributed to the glow peaks at lower temperatures, which decay faster than the ones at higher temperatures with storage time. The thermal fading of the window glass sample at room temperature showed a relatively sharp decay of about 60% occurring over a period of 28 days, after which the decay rate is small for a measured period of 250 days. In order to the improve the post-irradiation stability of the glow curve, the glass samples were heated after irradiation. To remove the unstable TL peaks responsible for the initial rapid fading, post-irradiation heating at 160 °C for 10 min was found to be the most suitable procedure. The dosimetric characteristics of the post-irradiation heated window glass examined in this study include fading, gamma photon dose-response, reproducibility, batch sensitivity, humidity influence, a dose-rate effect and photon energy response. Dose-response was found to be appropriate for dosimetry in the range 5 Gy to 10 kGy. The post-irradiation heating procedure did not affect the main dosimetric characteristics of the window glass samples. The results in this work suggest that the materials could, by using the TL technique, be a suitable candidate for alternative dose measurements in radiation processing, provided that a judicious choice of the post-irradiation heat temperature is made to minimize fading.

  14. Continuing Professional Development in the quantity surveying ...

    African Journals Online (AJOL)

    1991-01-01

    . .... South African Council for Quantity Surveyors (SACQS) to implement a policy of ... In addition to withdrawing the administration/management of the policy .... practice; assisting human resource personnel to set objectives for.

  15. Multimodal semantic quantity representations: further evidence from Korean Sign Language

    Directory of Open Access Journals (Sweden)

    Frank eDomahs

    2012-01-01

    Full Text Available Korean deaf signers performed a number comparison task on pairs of Arabic digits. In their RT profiles, the expected magnitude effect was systematically modified by properties of number signs in Korean Sign Language in a culture-specific way (not observed in hearing and deaf Germans or hearing Chinese. We conclude that finger-based quantity representations are automatically activated even in simple tasks with symbolic input although this may be irrelevant and even detrimental for task performance. These finger-based numerical representations are accessed in addition to another, more basic quantity system which is evidenced by the magnitude effect. In sum, these results are inconsistent with models assuming only one single amodal representation of numerical quantity.

  16. Uncertainty propagation with functionally correlated quantities

    CERN Document Server

    Giordano, Mosè

    2016-01-01

    Many uncertainty propagation software exist, written in different programming languages, but not all of them are able to handle functional correlation between quantities. In this paper we review one strategy to deal with uncertainty propagation of quantities that are functionally correlated, and introduce a new software offering this feature: the Julia package Measurements.jl. It supports real and complex numbers with uncertainty, arbitrary-precision calculations, mathematical and linear algebra operations with matrices and arrays.

  17. On the Hojman conservation quantities in Cosmology

    Directory of Open Access Journals (Sweden)

    A. Paliathanasis

    2016-04-01

    Full Text Available We discuss the application of the Hojman's Symmetry Approach for the determination of conservation laws in Cosmology, which has been recently applied by various authors in different cosmological models. We show that Hojman's method for regular Hamiltonian systems, where the Hamiltonian function is one of the involved equations of the system, is equivalent to the application of Noether's Theorem for generalized transformations. That means that for minimally-coupled scalar field cosmology or other modified theories which are conformally related with scalar-field cosmology, like f(R gravity, the application of Hojman's method provide us with the same results with that of Noether's Theorem. Moreover we study the special Ansatz. ϕ(t=ϕ(a(t, which has been introduced for a minimally-coupled scalar field, and we study the Lie and Noether point symmetries for the reduced equation. We show that under this Ansatz, the unknown function of the model cannot be constrained by the requirement of the existence of a conservation law and that the Hojman conservation quantity which arises for the reduced equation is nothing more than the functional form of Noetherian conservation laws for the free particle. On the other hand, for f(T teleparallel gravity, it is not the existence of Hojman's conservation laws which provide us with the special function form of f(T functions, but the requirement that the reduced second-order differential equation admits a Jacobi Last multiplier, while the new conservation law is nothing else that the Hamiltonian function of the reduced equation.

  18. Radiation exposure of the patient in diagnostic nuclear medicine. Experimental studies of the biokinetics of {sup 111}In-DTPA-D-Phe{sup 1}-octreotide, {sup 99m}Tc-MIBI, {sup 14}C-triolein and {sup 14}C-urea, and development of dosimetric models

    Energy Technology Data Exchange (ETDEWEB)

    Leide Svegborn, S

    1999-03-01

    Biokinetic and dosimetric models for a number of clinically used radiopharmaceuticals, for which information on the radiation dosimetry is scarce, have been produced. On patients undergoing investigations with {sup 111}In-DTPA-D-Phe{sup 1}-octreotide (for diagnosis of neuroendocrine tumours) and {sup 99m}Tc-MIBI (for myocardial perfusion imaging), whole body gamma camera scanning was performed several times after administration of the radiopharmaceutical. Total body and organ activity content was determined using the geometric mean of the number of counts in two 180 deg opposed planar images. A thorough investigation of sources influencing the accuracy of the quantification of activity was carried out, showing an overall uncertainty varying from 10% to 30% for organs with a significant uptake and 5% for the whole body. The activity in blood and urine was also measured. {sup 111}In-DTPA-D-Phe{sup 1}-octreotide was predominantly excreted via the kidney-bladder system and a typical investigation with 1200 MBq resulted in an effective dose of 8.4 mSv (0.076 mSv/MBq). {sup 99m}Tc-MIBI was to a great extent excreted via the gastrointestinal tract and an investigation with 1200 MBq resulted in an effective dose of 13 mSv (0.011 mSv/MBq). Accelerator mass spectrometry (AMS) was used to investigate the possibility to measure ultra-low activity concentrations of {sup 14}CO{sub 2}, in exhaled air from patients undergoing {sup 14}C-breath tests, with special application to {sup 14}C-triolein (for study of fat malabsorption). AMS was proven to be a useful technique for long-term retention studies of {sup 14}C, and was used together with liquid scintillation counting in an investigation of the biokinetics of {sup 14}C-urea in adult and paediatric patients (for diagnosis of Helicobacter pylori infection in the upper gastrointestinal tract). The effective dose for {sup 14}C-urea was 0.019 mSv/MBq for adults and from 0.041 to 0.019 mSv/MBq for seven- to fourteen -year-old children

  19. The dosimetric impact of gadolinium-based contrast media in GBM brain patient plans for a MRI-Linac

    Science.gov (United States)

    Bilal Ahmad, Syed; Paudel, Moti Raj; Sarfehnia, Arman; Kim, Anthony; Pang, Geordi; Ruschin, Mark; Sahgal, Arjun; Keller, Brian M.

    2017-08-01

    Dosimetric effects of gadolinium based contrast media (Gadovist) were evaluated for the Elekta MRI linear accelerator using the research version of the Monaco treatment planning system (TPS). In order to represent a gadolinium uptake, the contrast was manually assigned to a phantom as well as to the gross tumour volume (GTV) of 6 glioblastoma multiforme (GBM) patients. A preliminary estimate of the dose enhancement, due to gadolinium, was performed using the phantom irradiated with a single beam. A more complicated assessment was performed for the GBM patients using a 7 field IMRT technique. The material table in Monaco was modified in order to identify the presence of a non-biological material. The dose distribution was modelled using GPUMCD (MC algorithm in Monaco) for an unmodified (or default) material table (DMT) as well as for a modified (or custom) material table (CMT) for both the phantom and patients. Various concentrations ranging between 8 and 157 mg ml-1 were used to represent the gadolinium uptake in the patient’s GTV. It was assumed that the gadolinium concentration remained the same for the entire course of radiation treatment. Results showed that at the tissue-Gadovist interface, inside the phantom, dose scored using the DMT was 7% lower compared to that using the CMT for 157 mg ml-1 concentration of gadolinium. Dosimetric differences in the case of the patient study were measured using the DVH parameters. D 50% was higher by 6% when the DMT was used compared to the CMT for dose modelling for a gadolinium concentration of 157 mg ml-1. This difference decreased gradually with decreasing concentration of gadolinium. It was concluded that dosimetric differences can be quantified in Monaco if the tumour-gadolinium concentration is more than 23 mg ml-1. If the gadolinium concentration is lower than 23 mg ml-1, then a correction for the presence of gadolinium may not be necessary in the TPS.

  20. Comprehensive Australasian multicentre dosimetric intercomparison: issues, logistics and recommendations.

    Science.gov (United States)

    Ebert, M A; Harrison, K M; Cornes, D; Howlett, S J; Joseph, D J; Kron, T; Hamilton, C S; Denham, J W

    2009-02-01

    The present paper describes the logistics of the 2004-2008 Australasian Level III Dosimetry Intercomparison. Dosimetric intercomparisons (or 'audits') can be used in radiotherapy to evaluate the accuracy and quality of radiation delivery. An intercomparison was undertaken in New Zealand and Australia to evaluate the feasibility and logistics of ongoing dosimetric intercomparisons that evaluate all steps in the radiotherapy treatment process, known as a 'Level III' intercomparison. The study commenced in 2002 with the establishment of a study team, definition of the study protocol, acquisition of appropriate equipment and recruitment of participating radiotherapy centres. Measurements were undertaken between October 2004 and March 2008, and included collation of data on time, costs and logistics of the study. Forty independent Australian and New Zealand radiotherapy centres agreed to participate. Measurement visits were made to 37 of these centres. Data is presented on the costs of the study and the level of support required. The study involved the participation of 16 staff at the study centre who invested over 4000 hours in the study, and of over 200 professionals at participating centres. Recommendations are provided for future phantom-based intercomparisons. It is hoped that the present paper will be of benefit to any centres or groups contemplating similar activities by identifying the processes involved in establishing the study, the potential hazards and pitfalls, and expected resource requirements.

  1. Dosimetric Algorithm to Reproduce Isodose Curves Obtained from a LINAC

    Science.gov (United States)

    Estrada Espinosa, Julio Cesar; Martínez Ovalle, Segundo Agustín; Pereira Benavides, Cinthia Kotzian

    2014-01-01

    In this work isodose curves are obtained by the use of a new dosimetric algorithm using numerical data from percentage depth dose (PDD) and the maximum absorbed dose profile, calculated by Monte Carlo in a 18 MV LINAC. The software allows reproducing the absorbed dose percentage in the whole irradiated volume quickly and with a good approximation. To validate results an 18 MV LINAC with a whole geometry and a water phantom were constructed. On this construction, the distinct simulations were processed by the MCNPX code and then obtained the PDD and profiles for the whole depths of the radiation beam. The results data were used by the code to produce the dose percentages in any point of the irradiated volume. The absorbed dose for any voxel's size was also reproduced at any point of the irradiated volume, even when the voxels are considered to be of a pixel's size. The dosimetric algorithm is able to reproduce the absorbed dose induced by a radiation beam over a water phantom, considering PDD and profiles, whose maximum percent value is in the build-up region. Calculation time for the algorithm is only a few seconds, compared with the days taken when it is carried out by Monte Carlo. PMID:25045398

  2. Dosimetric algorithm to reproduce isodose curves obtained from a LINAC.

    Science.gov (United States)

    Estrada Espinosa, Julio Cesar; Martínez Ovalle, Segundo Agustín; Pereira Benavides, Cinthia Kotzian

    2014-01-01

    In this work isodose curves are obtained by the use of a new dosimetric algorithm using numerical data from percentage depth dose (PDD) and the maximum absorbed dose profile, calculated by Monte Carlo in a 18 MV LINAC. The software allows reproducing the absorbed dose percentage in the whole irradiated volume quickly and with a good approximation. To validate results an 18 MV LINAC with a whole geometry and a water phantom were constructed. On this construction, the distinct simulations were processed by the MCNPX code and then obtained the PDD and profiles for the whole depths of the radiation beam. The results data were used by the code to produce the dose percentages in any point of the irradiated volume. The absorbed dose for any voxel's size was also reproduced at any point of the irradiated volume, even when the voxels are considered to be of a pixel's size. The dosimetric algorithm is able to reproduce the absorbed dose induced by a radiation beam over a water phantom, considering PDD and profiles, whose maximum percent value is in the build-up region. Calculation time for the algorithm is only a few seconds, compared with the days taken when it is carried out by Monte Carlo.

  3. Dosimetric Algorithm to Reproduce Isodose Curves Obtained from a LINAC

    Directory of Open Access Journals (Sweden)

    Julio Cesar Estrada Espinosa

    2014-01-01

    Full Text Available In this work isodose curves are obtained by the use of a new dosimetric algorithm using numerical data from percentage depth dose (PDD and the maximum absorbed dose profile, calculated by Monte Carlo in a 18 MV LINAC. The software allows reproducing the absorbed dose percentage in the whole irradiated volume quickly and with a good approximation. To validate results an 18 MV LINAC with a whole geometry and a water phantom were constructed. On this construction, the distinct simulations were processed by the MCNPX code and then obtained the PDD and profiles for the whole depths of the radiation beam. The results data were used by the code to produce the dose percentages in any point of the irradiated volume. The absorbed dose for any voxel’s size was also reproduced at any point of the irradiated volume, even when the voxels are considered to be of a pixel’s size. The dosimetric algorithm is able to reproduce the absorbed dose induced by a radiation beam over a water phantom, considering PDD and profiles, whose maximum percent value is in the build-up region. Calculation time for the algorithm is only a few seconds, compared with the days taken when it is carried out by Monte Carlo.

  4. Dosimetric characteristics of the Siemens IGRT carbon fiber tabletop.

    Science.gov (United States)

    Spezi, Emiliano; Ferri, Andrea

    2007-01-01

    In this work, the dosimetric characteristics of a new commercial carbon fiber treatment table are investigated. The photon beam attenuation properties of the Siemens image-guided radiation therapy (IGRT) tabletop were studied in detail. Two sets of dosimetric measurements were performed. In the first experiment a polystyrene slab phantom was used: the central axis attenuation and the skin-sparing detriment were investigated. In the second experiment, the off-axis treatment table transmission was investigated using a polystyrene cylindrical phantom. Measurements were taken at the isocenter for a 360 degrees rotation of the radiation beam. Our results show that the photon beam attenuation of the Siemens IGRT carbon fiber tabletop varies from a minimum of 2.1% (central axis) to a maximum of 4.6% (120 degrees and 240 degrees beam incidence). The beam entrance dose increases from 82% to 97% of the dose at the depth of maximum for a clinical 6-MV radiation field. The depth of maximum also decreases by 0.4 cm. Despite the wedge cross section of the table the beam attenuation properties of the IGRT tabletop remain constant along the longitudinal direction. American Association of Medical Dosimetrists.

  5. Determination of dosimetric parameters for shielded 153Gd source in prostate cancer brachytherapy

    Science.gov (United States)

    Ghorbani, Mahdi; Ghatei, Najmeh; Mehrpouyan, Mohammad; Meigooni, Ali S.; Shahraini, Ramin

    2017-01-01

    Abstract Background Interstitial rotating shield brachytherapy (I-RSBT) is a recently developed method for treatment of prostate cancer. In the present study TG-43 dosimetric parameters of a 153Gd source were obtained for use in I-RSBT. Materials and methods A 153Gd source located inside a needle including a Pt shield and an aluminum window was simulated using MCNPX Monte Carlo code. Dosimetric parameters of this source model, including air kerma strength, dose rate constant, radial dose function and 2D anisotropy function, with and without the shields were calculated according to the TG-43 report. Results The air kerma strength was found to be 6.71 U for the non-shielded source with 1 GBq activity. This value was found to be 0.04 U and 6.19 U for the Pt shield and Al window cases, respectively. Dose rate constant for the non-shielded source was found to be 1.20 cGy/(hU). However, for a shielded source with Pt and aluminum window, dose rate constants were found to be 0.07 cGy/(hU) and 0.96 cGy/(hU), on the shielded and window sides, respectively. The values of radial dose function and anisotropy function were tabulated for these sources. Additionally, isodose curves were drawn for sources with and without shield, in order to evaluate the effect of shield on dose distribution. Conclusions Existence of the Pt shield may greatly reduce the dose to organs at risk and normal tissues which are located toward the shielded side. The calculated air kerma strength, dose rate constant, radial dose function and 2D anisotropy function data for the 153Gd source for the non-shielded and the shielded sources can be used in the treatment planning system (TPS). PMID:28265239

  6. Transformation of Physical DVHs to Radiobiologically Equivalent Ones in Hypofractionated Radiotherapy Analyzing Dosimetric and Clinical Parameters: A Practical Approach for Routine Clinical Practice in Radiation Oncology

    Directory of Open Access Journals (Sweden)

    Zoi Thrapsanioti

    2013-01-01

    Full Text Available Purpose. The purpose of this study was to transform DVHs from physical to radiobiological ones as well as to evaluate their reliability by correlations of dosimetric and clinical parameters for 50 patients with prostate cancer and 50 patients with breast cancer, who were submitted to Hypofractionated Radiotherapy. Methods and Materials. To achieve this transformation, we used both the linear-quadratic model (LQ model and the Niemierko model. The outcome of radiobiological DVHs was correlated with acute toxicity score according to EORTC/RTOG criteria. Results. Concerning the prostate radiotherapy, there was a significant correlation between RTOG acute rectal toxicity and ( and ( dosimetric parameters, calculated for  Gy. Moreover, concerning the breast radiotherapy there was a significant correlation between RTOG skin toxicity and dosimetric parameter, calculated for both  Gy ( and  Gy (. The new tool seems reliable and user-friendly. Conclusions. Our proposed model seems user-friendly. Its reliability in terms of agreement with the presented acute radiation induced toxicity was satisfactory. However, more patients are needed to extract safe conclusions.

  7. Construction of a computational exposure model for dosimetric calculations using the EGS4 Monte Carlo code and voxel phantoms; Construcao de um modelo computacional de exposicao para calculos dosimetricos utilizando o codigo Monte Carlo EGS4 e fantomas de voxels

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Jose Wilson

    2004-07-15

    The MAX phantom has been developed from existing segmented images of a male adult body, in order to achieve a representation as close as possible to the anatomical properties of the reference adult male specified by the ICRP. In computational dosimetry, MAX can simulate the geometry of a human body under exposure to ionizing radiations, internal or external, with the objective of calculating the equivalent dose in organs and tissues for occupational, medical or environmental purposes of the radiation protection. This study presents a methodology used to build a new computational exposure model MAX/EGS4: the geometric construction of the phantom; the development of the algorithm of one-directional, divergent, and isotropic radioactive sources; new methods for calculating the equivalent dose in the red bone marrow and in the skin, and the coupling of the MAX phantom with the EGS4 Monte Carlo code. Finally, some results of radiation protection, in the form of conversion coefficients between equivalent dose (or effective dose) and free air-kerma for external photon irradiation are presented and discussed. Comparing the results presented with similar data from other human phantoms it is possible to conclude that the coupling MAX/EGS4 is satisfactory for the calculation of the equivalent dose in radiation protection. (author)

  8. Electromagnetic Quantities in Black Hole Magnetosphere

    Institute of Scientific and Technical Information of China (English)

    汪定雄; 马任意; 雷卫华; 姚国政

    2004-01-01

    Some electromagnetic quantities in the black hole (BH) magnetosphere are discussed by considering the coexistence of the Blandford-Znajek process and the magnetic coupling process. These quantities are (i) flux of electromagnetic energy and angular momentum transferred between the BH and the disc, (ii) poloidal currents flowing on the horizon and disc, (iii) poloidal electric field on the horizon, (iv) toroidal magnetic field in the BH magnetosphere,and (v) voltage drop across the magnetic coupling region on the horizon. It turns out that these quantities are determined mainly by three parameters: (i) the positions relative to the corotation magnetic surface, (ii) the BH spin, and (iii) the power-law index for the variation of the magnetic field on the disc.

  9. A conserved quantity in thin body dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Hanna, J.A., E-mail: hannaj@vt.edu [Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Pendar, H. [Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)

    2016-02-15

    Thin, solid bodies with metric symmetries admit a restricted form of reparameterization invariance. Their dynamical equilibria include motions with both rigid and flowing aspects. On such configurations, a quantity is conserved along the intrinsic coordinate corresponding to the symmetry. As an example of its utility, this conserved quantity is combined with linear and angular momentum currents to construct solutions for the equilibria of a rotating, flowing string, for which it is akin to Bernoulli's constant. - Highlights: • A conserved quantity relevant to the dynamical equilibria of thin structures. • A mixed Lagrangian–Eulerian non-material action principle for fixed windows of axially moving systems. • Analytical solutions for rotating, flowing strings (yarn balloons). • Noether meets Bernoulli in a textile factory.

  10. Dosimetric and Late Radiation Toxicity Comparison Between Iodine-125 Brachytherapy and Stereotactic Radiation Therapy for Juxtapapillary Choroidal Melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Krema, Hatem, E-mail: htmkrm19@yahoo.com [Department of Ocular Oncology, Princess Margaret Hospital/University Health Network, University of Toronto, Toronto, Ontario (Canada); Heydarian, Mostafa [Department of Radiation Medicine, Princess Margaret Hospital/University Health Network, University of Toronto, Toronto, Ontario (Canada); Beiki-Ardakani, Akbar [Department of Radiation Oncology, Princess Margaret Hospital/University Health Network, University of Toronto, Toronto, Ontario (Canada); Weisbrod, Daniel [Department of Ocular Oncology, Princess Margaret Hospital/University Health Network, University of Toronto, Toronto, Ontario (Canada); Xu, Wei [Department of Biostatistics, Princess Margaret Hospital/University Health Network, University of Toronto, Toronto, Ontario (Canada); Laperriere, Normand J.; Sahgal, Arjun [Department of Radiation Oncology, Princess Margaret Hospital/University Health Network, University of Toronto, Toronto, Ontario (Canada)

    2013-07-01

    Purpose: To compare the dose distributions and late radiation toxicities for {sup 125}I brachytherapy (IBT) and stereotactic radiation therapy (SRT) in the treatment of juxtapapillary choroidal melanoma. Methods: Ninety-four consecutive patients with juxtapapillary melanoma were reviewed: 30 have been treated with IBT and 64 with SRT. Iodine-125 brachytherapy cases were modeled with plaque simulator software for dosimetric analysis. The SRT dosimetric data were obtained from the Radionics XKnife RT3 software. Mean doses at predetermined intraocular points were calculated. Kaplan-Meier estimates determined the actuarial rates of late toxicities, and the log–rank test compared the estimates. Results: The median follow-up was 46 months in both cohorts. The 2 cohorts were balanced with respect to pretreatment clinical and tumor characteristics. Comparisons of radiation toxicity rates between the IBT and SRT cohorts yielded actuarial rates at 50 months for cataracts of 62% and 75% (P=.1), for neovascular glaucoma 8% and 47% (P=.002), for radiation retinopathy 59% and 89% (P=.0001), and for radiation papillopathy 39% and 74% (P=.003), respectively. Dosimetric comparisons between the IBT and SRT cohorts yielded mean doses of 12.8 and 14.1 Gy (P=.56) for the lens center, 17.6 and 19.7 Gy (P=.44) for the lens posterior pole, 13.9 and 10.8 Gy (P=.30) for the ciliary body, 61.9 and 69.7 Gy (P=.03) for optic disc center, and 48.9 and 60.1 Gy (P<.0001) for retina at 5-mm distance from tumor margin, respectively. Conclusions: Late radiation-induced toxicities were greater with SRT, which is secondary to the high-dose exposure inherent to the technique as compared with IBT. When technically feasible, IBT is preferred to treat juxtapapillary choroidal melanoma.

  11. Volumetric modulated arc radiotherapy sparing the thyroid gland for early-stage glottic cancer: A dosimetrical analysis.

    Science.gov (United States)

    Kim, Eun Seok; Yeo, Seung-Gu

    2014-06-01

    Previous studies on advanced radiotherapy (RT) techniques for early stage glottic cancer have focused on sparing the carotid artery. However, the aim of the present study was to evaluate the dosimetric advantages of volumetric modulated arc therapy (VMAT) in terms of sparing the thyroid gland in early-stage glottic cancer patients. In total, 15 cT1N0M0 glottic cancer patients treated with definitive RT using VMAT were selected, and for dosimetric comparison, a conventional RT plan comprising opposed-lateral wedged fields was generated for each patient. The carotid artery, thyroid gland and spinal cord were considered organs at risk. The prescription dose was 63 Gy at 2.25 Gy per fraction. For the thyroid gland and carotid artery, all compared parameters were significantly lower with VMAT compared with conventional RT. For the thyroid gland, the median reduction rates of the mean dose (Dmean), the volume receiving ≥30% of the prescription dose (V30) and the V50 were 32.6, 40.9 and 46.0%, respectively. The Dmean was 14.7±2.6 Gy when using VMAT compared with 22.2±3.9 Gy when using conventional RT. The differences between the techniques in terms of planning target volume coverage and dose homogeneity were not significant. When considering a recent normal tissue complication probability model, which indicated the mean thyroid gland dose as the most significant predictor of radiation-induced hypothyroidism, the dosimetric advantage shown in this study may be valuable in reducing hypothyroidism following RT for early stage glottic cancer patients.

  12. SU-F-BRE-04: Construction of 3D Printed Patient Specific Phantoms for Dosimetric Verification Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ehler, E; Higgins, P; Dusenbery, K [University of Minnesota, Minneapolis, MN (United States)

    2014-06-15

    Purpose: To validate a method to create per patient phantoms for dosimetric verification measurements. Methods: Using a RANDO phantom as a substitute for an actual patient, a model of the external features of the head and neck region of the phantom was created. A phantom was used instead of a human for two reasons: to allow for dosimetric measurements that would not be possible in-vivo and to avoid patient privacy issues. Using acrylonitrile butadiene styrene thermoplastic as the building material, a hollow replica was created using the 3D printer filled with a custom tissue equivalent mixture of paraffin wax, magnesium oxide, and calcium carbonate. A traditional parallel-opposed head and neck plan was constructed. Measurements were performed with thermoluminescent dosimeters in both the RANDO phantom and in the 3D printed phantom. Calculated and measured dose was compared at 17 points phantoms including regions in high and low dose regions and at the field edges. On-board cone beam CT was used to localize both phantoms within 1mm and 1° prior to radiation. Results: The maximum difference in calculated dose between phantoms was 1.8% of the planned dose (180 cGy). The mean difference between calculated and measured dose in the anthropomorphic phantom and the 3D printed phantom was 1.9% ± 2.8% and −0.1% ± 4.9%, respectively. The difference between measured and calculated dose was determined in the RANDO and 3D printed phantoms. The differences between measured and calculated dose in each respective phantom was within 2% for 12 of 17 points. The overlap of the RANDO and 3D printed phantom was 0.956 (Jaccard Index). Conclusion: A custom phantom was created using a 3D printer. Dosimetric calculations and measurements showed good agreement between the dose in the RANDO phantom (patient substitute) and the 3D printed phantom.

  13. 16 CFR 500.19 - Conversion of SI metric quantities to inch/pound quantities and inch/pound quantities to SI...

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Conversion of SI metric quantities to inch/pound quantities and inch/pound quantities to SI metric quantities. 500.19 Section 500.19 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENT OF GENERAL POLICY OR INTERPRETATION AND EXEMPTIONS UNDER THE FAIR PACKAGING...

  14. Variation and Change in Northern Bavarian Quantity

    Science.gov (United States)

    Drake, Derek

    2013-01-01

    This dissertation presents new research on the "Bavarian Quantity Law" (the BQL) in the northern Bavarian dialect of Hahnbach. Building upon earlier investigation of the BQL (cf. Bannert 1976a,b for Central Bavarian) this study examines the historical, phonological, and phonetic motivations for this feature as well the variability in its…

  15. Variation and Change in Northern Bavarian Quantity

    Science.gov (United States)

    Drake, Derek

    2013-01-01

    This dissertation presents new research on the "Bavarian Quantity Law" (the BQL) in the northern Bavarian dialect of Hahnbach. Building upon earlier investigation of the BQL (cf. Bannert 1976a,b for Central Bavarian) this study examines the historical, phonological, and phonetic motivations for this feature as well the variability in its…

  16. Factors affecting lactose quantity in raw milk

    Directory of Open Access Journals (Sweden)

    Rubporn Kittivachra

    2007-07-01

    Full Text Available The purpose of this study was to characterize factors affecting lactose quantities in raw cow's milk. This study combined the survey design with laboratory analysis. Selected farm members of Nong Poh Dairy Cooperatives, from Ban Pong and Photharam Districts, Ratchaburi Province, were sampled. From the selected farms, data collected included lactose quantities in the raw milk and dairy farming information. The raw milk of selected farms was sampled at the delivery site of Nong Poh dairy cooperatives in the morning during December 2003 till February 2004. Lactose in the raw milk was then quantified by the Fourier Transform Infrared Analysis (FTIR using the MilkoScan FT6000 at the Department of Livestock Development. The farm owners or managers of selected farms were in-depth interviewed on dairy farming information including cowsí health and cows' diet. The data revealed that all cows from the selected farms were fed with concentrate diet purchased from Nong Poh Dairy Cooperatives and grass as high fiber diets. Sample of eighteen farms also fed their cows with one of supplements: corn stem, soybean meal, or rice straw. All cows from these farms were Holstein-Friesian Hybrid. As supplemented high fiber diets, corn stem significantly increased the lactose quantities over soybean meal and rice straw (planned comparison, pvalue = 0.044. The study concluded that some high fiber diets, specifically corn stem, significantly contributed to the lactose quantities in raw milk.

  17. Quantity language speakers show enhanced subcortical processing.

    Science.gov (United States)

    Dawson, Caitlin; Aalto, Daniel; Šimko, Juraj; Putkinen, Vesa; Tervaniemi, Mari; Vainio, Martti

    2016-07-01

    The complex auditory brainstem response (cABR) can reflect language-based plasticity in subcortical stages of auditory processing. It is sensitive to differences between language groups as well as stimulus properties, e.g. intensity or frequency. It is also sensitive to the synchronicity of the neural population stimulated by sound, which results in increased amplitude of wave V. Finnish is a full-fledged quantity language, in which word meaning is dependent upon duration of the vowels and consonants. Previous studies have shown that Finnish speakers have enhanced behavioural sound duration discrimination ability and larger cortical mismatch negativity (MMN) to duration change compared to German and French speakers. The next step is to find out whether these enhanced duration discrimination abilities of quantity language speakers originate at the brainstem level. Since German has a complementary quantity contrast which restricts the possible patterns of short and long vowels and consonants, the current experiment compared cABR between nonmusician Finnish and German native speakers using seven short complex stimuli. Finnish speakers had a larger cABR peak amplitude than German speakers, while the peak onset latency was only affected by stimulus intensity and spectral band. The results suggest that early cABR responses are better synchronised for Finns, which could underpin the enhanced duration sensitivity of quantity language speakers. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  18. CALL, Prewriting Strategies, and EFL Writing Quantity

    Science.gov (United States)

    Shafiee, Sajad; Koosha, Mansour; Afghar, Akbar

    2015-01-01

    This study sought to explore the effect of teaching prewriting strategies through different methods of input delivery (i.e. conventional, web-based, and hybrid) on EFL learners' writing quantity. In its quasi-experimental study, the researchers recruited 98 available sophomores, and assigned them to three experimental groups (conventional,…

  19. Practice Makes Perfect: Contracting Quantity and Quality.

    Science.gov (United States)

    Reichert, Nancy

    2003-01-01

    Discusses how contract grading promotes quality writing as well as a larger quantity of writing. Considers how teachers can use contract grading to support and promote the behaviors, thinking skills, and writing skills they believe will help students create quality writing. Notes that contract grading leads students to write more, to have fewer…

  20. Measurements of non-physical quantities

    Science.gov (United States)

    Shishkin, Igor F.

    2016-11-01

    The aim of the paper is to suggest an approach to development of a theory of measurements for non-physical quantities. For these measurements it is not possible to ensure traceability because of their exclusive nature as substantiated by the author. This theory is presented as particularly important one for social and human sciences.

  1. 7 CFR 929.14 - Marketable quantity.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Marketable quantity. 929.14 Section 929.14 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... market demand and to provide for an adequate carryover. ...

  2. 30 CFR 75.325 - Air quantity.

    Science.gov (United States)

    2010-07-01

    ... of permanent supports. (3) If machine mounted dust collectors or diffuser fans are used, the approved... currents cannot be controlled and air measurements cannot be obtained, the air shall have perceptible... results of sampling that demonstrate that the lesser air quantity will maintain continuous compliance...

  3. 7 CFR 35.13 - Minimum quantity.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Minimum quantity. 35.13 Section 35.13 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS EXPORT...

  4. Potential ocular damage from microwave exposure during electrosurgery: dosimetric survey

    Energy Technology Data Exchange (ETDEWEB)

    Paz, J.D.; Milliken, R.; Ingram, W.T.; Frank, A.; Atkin, A.

    1987-07-01

    A dosimetric survey of microwave radiation emitted by electrosurgical units used in operating rooms indicated that surgeons expose themselves to levels that may be hazardous, and that ocular exposures are especially high: 20 cm from the active lead, electric field strength at the eye/forehead position was 9.0 X 10(6) V2/M2 for the monopolar unit; and magnetic field strength at this position reached a magnitude of 3.5 A2/M2. These electric and magnetic fields exceeded the TLVs of the American National Standards Institute. The authors concluded that the high levels of microwave radiation generated by electrosurgery devices should receive immediate attention to assess health effects associated with such exposures.

  5. Dosimetric properties of natural quartz grains extracted from fired materials

    DEFF Research Database (Denmark)

    Bluszcz, A.; Bøtter-Jensen, L.

    1995-01-01

    The paper describes an examination of the dosimetric properties of natural quartz grains extracted from ancient fired materials. Eleven samples of different origin were tested for their TL and GLSL (green light stimulated luminescence) sensitivities within the mGy dose range. Very promising results...... were obtained showing the possibility of measuring the doses of around 10 mGy with 1% precision using GLSL or TL and using the single aliquot technique for natural quartz as a dosimeter. The lowest detectable dose was estimated to be lower than 500 mu Gy. The results obtained indicate that natural...... quartz grains from selected materials could be used for the dosimetry of environmental gamma radiation for the purposes of paleodosimetric dating methods as well as for accident dosimetry....

  6. Dosimetric properties of a scanned beam microtron at low monitor unit settings: importance for conformal therapy.

    Science.gov (United States)

    Humm, J L; Larsson, A; Lief, E P

    1996-03-01

    The dosimetric stability, linearity, dose rate dependence, and flatness of both photon and electron beams have been evaluated for a racetrack microtron at low monitor unit settings. For photons, the variation in dosimetric output about the mean is 3% at 20 cm, even at only 3 MU, in contrast with other scanned beam accelerators. Broad electron beams on the microtron are created by the superposition of the elementary beam pulses either directly from the scan magnets, or after their broadening through a scattering foil. The dosimetric instability both with and without the foil was less than 0.6% for both the 25- and 50-MeV electrons. Dose nonlinearity was microtron exhibits dosimetric properties which fulfill the recommendations of Task Groups 21 and 25. Based on the stability of the scanned beam at low monitor unit settings, the microtron can be used for 3-D conformal therapy with both photons and electrons.

  7. Dosimetrically determined doses of radioiodine for the treatment of metastatic thyroid carcinoma.

    Science.gov (United States)

    Van Nostrand, Douglas; Atkins, Frank; Yeganeh, Fred; Acio, Elmo; Bursaw, Randy; Wartofsky, Leonard

    2002-02-01

    In the absence of definitive studies relating radioiodine dose to outcomes, selection of a dose of radioiodine to treat metastatic thyroid carcinoma is problematic, and several approaches have been used. These include empiric fixed doses and doses used on dosimetric approaches specific for each patient. This paper is a review of the rationale and technique for dosimetrically-determined doses of radioiodine for the treatment of metastatic thyroid carcinoma. This review (1) discusses the alternatives for selection of a dose, (2) discusses the two major approaches for determining radioiodine doses dosimetrically, (3) briefly reviews several modifications of these approaches, (4) reviews the literature regarding the results, (5) discusses the side effects of these different approaches, and (6) concludes with recommendations for patient management and future research. This review does not address use of dosimetrically-determined doses of radioiodine for the initial ablation of thyroid tissue postoperatively.

  8. Effects of Dosimetrically Guided I-131 Therapy on Hematopoiesis in Patients With Differentiated Thyroid Cancer.

    Science.gov (United States)

    Bikas, Athanasios; Schneider, Mark; Desale, Sameer; Atkins, Frank; Mete, Mihriye; Burman, Kenneth D; Wartofsky, Leonard; Van Nostrand, Douglas

    2016-04-01

    A retrospective analysis was performed to evaluate the effects of dosimetrically-guided I-131 treatment on hematopoiesis. Statistically significant decreases in CBC parameters following a specific time-pattern were shown.

  9. Consumer-resource dynamics: quantity, quality, and allocation.

    Directory of Open Access Journals (Sweden)

    Wayne M Getz

    Full Text Available BACKGROUND: The dominant paradigm for modeling the complexities of interacting populations and food webs is a system of coupled ordinary differential equations in which the state of each species, population, or functional trophic group is represented by an aggregated numbers-density or biomass-density variable. Here, using the metaphysiological approach to model consumer-resource interactions, we formulate a two-state paradigm that represents each population or group in a food web in terms of both its quantity and quality. METHODOLOGY AND PRINCIPAL FINDINGS: The formulation includes an allocation function controlling the relative proportion of extracted resources to increasing quantity versus elevating quality. Since lower quality individuals senescence more rapidly than higher quality individuals, an optimal allocation proportion exists and we derive an expression for how this proportion depends on population parameters that determine the senescence rate, the per-capita mortality rate, and the effects of these rates on the dynamics of the quality variable. We demonstrate that oscillations do not arise in our model from quantity-quality interactions alone, but require consumer-resource interactions across trophic levels that can be stabilized through judicious resource allocation strategies. Analysis and simulations provide compelling arguments for the necessity of populations to evolve quality-related dynamics in the form of maternal effects, storage or other appropriate structures. They also indicate that resource allocation switching between investments in abundance versus quality provide a powerful mechanism for promoting the stability of consumer-resource interactions in seasonally forcing environments. CONCLUSIONS/SIGNIFICANCE: Our simulations show that physiological inefficiencies associated with this switching can be favored by selection due to the diminished exposure of inefficient consumers to strong oscillations associated with the

  10. A comparison of the dosimetric characteristics of a glass rod dosimeter and a thermoluminescent dosimeter for mailed dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Rah, Jeong-Eun [Department of Biomedical Engineering, Catholic University of Korea, College of Medicine, Seoul (Korea, Republic of); Research Institute of Biomedical Engineering, Catholic University of Korea, Seoul (Korea, Republic of); Hong, Ju-Young [Department of Radiation Oncology, Kangnam St. Mary' s Hospital, College of Medicine, Catholic University of Korea, Seoul (Korea, Republic of); Kim, Gwe-Ya [Department of Radiation Oncology, Austin Caner Centers, Austin, TX (United States); Kim, Yon-Lae [Department of Radiation Oncology, Konkuk University Hospital, Seoul (Korea, Republic of); Shin, Dong-Oh [Department of Radiation Oncology, Kyung Hee University, School of Medicine, Seoul (Korea, Republic of); Suh, Tae-Suk [Department of Biomedical Engineering, Catholic University of Korea, College of Medicine, Seoul (Korea, Republic of); Research Institute of Biomedical Engineering, Catholic University of Korea, Seoul (Korea, Republic of)], E-mail: suhsanta@catholic.ac.kr

    2009-01-15

    A radiophotoluminescent glass rod dosimeter (RPL-GRD) system has recently become commercially available. The purpose of this study was to investigate the dosimetric characteristics (reproducibility, linearity, fading, energy dependence and angular dependence) of the RPL-GRD for a mailed dosimeter and to compare it with LiF-TLD powder. In this study, the model GD-301 GRD and TLD-700 were powder type used. All measurements with the exception of angular dependence were performed in a water phantom using a holder stand. The RPL-GRD has better reproducibility than the TLD for the Co-60 beam as well as for the clinical photon beam. The RPL-GRD signal was linear as a function of applied dose in the range of 0.5-3 Gy for the Co-60 gamma rays. The fading of the RPL-GRD after a received dose of 2 Gy was initially found to be within 1.7% for five months. The energy dependence of both dosimeters was found to be less than 1.6% for photon beams, but was less than 5.0% for electron beams, which was in agreement with published data. The angular dependence of the RPL-GRD was measured to be approximately 1.4% for angles ranging {+-}90 deg. from the beam axis using a spherical polystyrene phantom. The measurements comparing RPL-GRD and TLD dosimetric characteristics demonstrated that the RPL-GRD is suitable for mailed dosimetry in a quality assurance (QA) audit program.

  11. Sleep quantity, quality and optimism in children.

    Science.gov (United States)

    Lemola, Sakari; Räikkönen, Katri; Scheier, Michael F; Matthews, Karen A; Pesonen, Anu-Katriina; Heinonen, Kati; Lahti, Jari; Komsi, Niina; Paavonen, Juulia E; Kajantie, Eero

    2011-03-01

    We tested the relationship of objectively measured sleep quantity and quality with positive characteristics of the child. Sleep duration, sleep latency and sleep efficiency were measured by an actigraph for an average of seven (range = 3-14) consecutive nights in 291 8-year-old children (standard deviation = 0.3 years). Children's optimism, self-esteem and social competence were rated by parents and/or teachers. Sleep duration showed a non-linear, reverse J-shaped relationship with optimism (P = 0.02), such that children with sleep duration in the middle of the distribution scored higher in optimism compared with children who slept relatively little. Shorter sleep latency was related to higher optimism (P = 0.01). The associations remained when adjusting for child's age, sex, body mass index, and parental level of education and optimism. In conclusion, sufficient sleep quantity and good sleep quality are related to children's positive characteristics. Our findings may inform why sleep quantity and quality and positive characteristics are associated with wellbeing in children. © 2010 European Sleep Research Society.

  12. Quantity discrimination in wolves (Canis lupus

    Directory of Open Access Journals (Sweden)

    Ewelina eUtrata

    2012-11-01

    Full Text Available Quantity discrimination has been studied extensively in different non-human animal species. In the current study, we tested eleven hand-raised wolves (Canis lupus in a two-way choice task. We placed a number of food items (one to four sequentially into two opaque cans and asked the wolves to choose the larger amount. Moreover, we conducted two additional control conditions to rule out non-numerical properties of the presentation that the animals might have used to make the correct choice. Our results showed that wolves are able to make quantitative judgments at the group, but also at the individual level even when alternative strategies such as paying attention to the surface area or time and total amount are ruled out. In contrast to previous canine studies on dogs (Canis familiaris and coyotes (Canis latrans, our wolves’ performance did not improve with decreasing ratio, referred to as Weber’s law. However, further studies using larger quantities than we used in the current setup are still needed to determine whether and when wolves’ quantity discrimination conforms to Weber’s law.

  13. Study and evaluation of the Siemens virtual wedge factor: dosimetric monitor system and variable field effects

    Energy Technology Data Exchange (ETDEWEB)

    Sendon Rio, J R Sendon; Martinez, C Otero; GarcIa, M Sanchez; Busto, R Lobato; Vega, V Luna; Sueiro, J Mosquera; Camean, M Pombar [Servizo de Radiofisica e Proteccion Radioloxica, Complexo Hospitalario Universitario de Santiago de Compostela (CHUS), Santiago de Compostela (Spain)], E-mail: jose.ramon.sendon.del.rio@sergas.es

    2008-03-07

    In the year 1997 Siemens introduced the virtual wedge in its accelerators. The idea was that a dose profile similar to that of a physical wedge can be obtained by moving one of the accelerator jaws at a constant speed while the dose rate is changing. This work explores the observed behaviour of virtual wedge factors. A model is suggested which takes into account that at any point in time, when the jaw moves, the dose at a point of interest in the phantom is not only due to the direct beam. It also depends on the scattered radiation in the phantom, the head scatter and the behaviour of the monitoring system of the accelerator. Measurements are performed in a Siemens Primus accelerator and compared to the model predictions. It is shown that the model agrees reasonably well with measurements spanning a wide range of conditions. A strong dependence of virtual wedge factors on the dosimetric board has been confirmed and an explanation has been given on how the balance between different contributions is responsible for virtual wedge factors values.

  14. Analytical calculation of central-axis dosimetric data for a dedicated 6-MV radiosurgery linear accelerator.

    Science.gov (United States)

    Yang, James N; Pino, Ramiro

    2008-10-01

    Narrow beams are extensively used in stereotactic radiosurgery. The accuracy of treatment planning dose calculation depends largely on how well the dosimetric data are measured during the machine commissioning. Narrow beams are characterized by the lack of lateral electronic equilibrium. The lateral electronic disequilibrium in the radiation field and detector's finite size are likely to compromise the accuracy in dose measurements in these beams. This may have a profound impact on outcome in patients who undergo stereotactic radiosurgery. To confirm the measured commissioning data for a dedicated 6-MV linear accelerator-based radiosurgery system, we developed an analytical model to calculate the narrow photon beam central-axis dose. This model is an extension of a previously reported method of Nizin and Mooij for the calculation of the absorbed dose under lateral electronic disequilibrium conditions at depth of dmax or greater. The scatter factor and tissue-maximum ratio were calculated for narrow beams using the parametrized model and compared to carefully measured results for the same beams. For narrow beam radii ranging from 0.2 to 1.5 cm, the differences between the analytical and measured scatter factors were no greater than 1.4%. In addition, the differences between the analytical and measured tissue-maximum ratios were within 3.3% for regions greater than the maximum dose depth. The estimated error of this analytical calculation was less than 2%, which is sufficient to validate measurement results.

  15. Dosimetric Comparison in Breast Radiotherapy of 4 MV and 6 MV on Physical Chest Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio [Nuclear Engineering Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Batista Nogueira, Luciana [Anatomy and Imaging Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Lima Souza Castro, Andre [Nuclear Engineering Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Institute of Radiation San Francisco, Belo Horizonte (Brazil); Alves de oliveira, Marcio; Galvao Dias, Humberto [Cancer Hospital in Uberlandia, Uberlandia (Brazil)

    2015-07-01

    According to the World Health Organization (2014) breast cancer is the main cause of death by cancer in women worldwide. The biggest challenge of radiotherapy in the treatment of cancer is to deposit the entire prescribed dose homogeneously in the breast, sparing the surrounding tissue. In this context, this paper aimed at evaluating and comparing internal dose distribution in the mammary gland based on experimental procedures submitted to two distinct energy spectra produced in breast cancer radiotherapy. The methodology consisted of reproducing opposite parallel fields used in the treatment of breast tumors in a chest phantom. This simulator with synthetic breast, composed of equivalent tissue material (TE), was previously developed by the NRI Research Group (UFMG). The computer tomography (CT) scan of the simulator was obtained antecedently. The radiotherapy planning systems (TPS) in the chest phantom were performed in the ECLIPSE system from Varian Medical Systems and CAT 3D system from MEVIS. The irradiations were reproduced in the Varian linear accelerator, model SL- 20 Precise, 6 MV energy and Varian linear accelerator, 4 MV Clinac 6x SN11 model. Calibrations of the absorbed dose versus optical density from radiochromic films were generated in order to obtain experimental dosimetric distribution at the films positioned within the glandular and skin equivalent tissues of the chest phantom. The spatial dose distribution showed equivalence with the TPS on measurement data performed in the 6 MV spectrum. The average dose found in radiochromic films placed on the skin ranged from 49 to 79%, and from 39 to 49% in the mammary areola, for the prescribed dose. Dosimetric comparisons between the spectra of 4 and 6 MV, keeping the constant geometry of the fields applied in the same phantom, will be presented showing their equivalence in breast radiotherapy, as well as the variations will be discussed. To sum up, the dose distribution has reached the value expected in

  16. Evaluation of fluence-based dose delivery incorporating the spatial variation of dosimetric leaf gap (DLG).

    Science.gov (United States)

    Kumaraswamy, Lalith K; Xu, Zhengzheng; Bailey, Daniel W; Schmitt, Jonathan D; Podgorsak, Matthew B

    2016-01-08

    The Eclipse treatment planning system uses a single dosimetric leaf gap (DLG) value to retract all multileaf collimator leaf positions during dose calculation to model the rounded leaf ends. This study evaluates the dosimetric impact of the 2D variation of DLG on clinical treatment plans based on their degree of fluence modulation. In-house software was developed to retrospectively apply the 2D variation of DLG to 61 clinically treated VMAT plans, as well as to several test plans. The level of modulation of the VMAT cases were determined by calculating their modulation complexity score (MCS). Dose measurements were done using the MapCHECK device at a depth of 5.0 cm for plans with and without the 2D DLG correction. Measurements were compared against predicted dose planes from the TPS using absolute 3%/3 mm and 2%/2 mm gamma criteria for test plans and for VMAT cases, respectively. The gamma pass rate for the 2 mm, 4 mm, and 6 mm sweep test plans increased by 23.2%, 28.7%, and 26.0%, respectively, when the measurements were corrected with 2D variation of DLG. The clinical anal VMAT cases, which had very high MLC modulation, showed the most improvement. The majority of the improvement occurred for doses created by the 1.0 cm width leaves for both the test plans and the VMAT cases. The gamma pass rates for the highly modulated head and neck (H&N) cases, moderately modulated prostate and esophageal cases, and minimally modulated brain cases improved only slightly when corrected with 2D variation of DLG. This is because these cases did not employ the 1.0 cm width leaves for dose calculation and delivery. These data suggest that, at the very least, the TPS plans with highly modulated fluences created by the 1.0 cm fields require 2D DLG correction. Incorporating the 2D variation of DLG for the highly modulated clinical treatment plans improves their planar dose gamma pass rates, especially for fields employing the outer 1.0 cm width MLC leaves. This is because there are

  17. Exact Solutions and Conserved Quantities in f(R,T) Gravity

    CERN Document Server

    Sharif, M

    2016-01-01

    This paper explores Noether and Noether gauge symmetries of anisotropic universe model in $f(R,T)$ gravity. We consider two particular models of this gravity and evaluate their symmetry generators as well as associated conserved quantities. We also find exact solution by using cyclic variable and investigate its behavior via cosmological parameters. The behavior of cosmological parameters turns out to be consistent with recent observations which indicates accelerated expansion of the universe. Next we study Noether gauge symmetry and corresponding conserved quantities for both isotropic and anisotropic universe models. We conclude that symmetry generators and the associated conserved quantities appear in all cases.

  18. Neutron sources and its dosimetric characteristics; Fuentes de neutrones y sus caracteristicas dosimetricas

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Mercado S, G.A. [Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas (Mexico); Gallego D, E.; Lorente F, A. [Universidad Politecnica de Madrid, C/Jose Gutierrez Abascal 2, E-28006 Madrid (Spain)

    2005-07-01

    By means of Monte Carlo methods the spectra of the produced neutrons {sup 252} Cf, {sup 252} Cf/D{sub 2}O, {sup 241} Am Be, {sup 239} Pu Be, {sup 140} La Be, {sup 239} Pu{sup 18}O{sub 2} and {sup 226} Ra Be have been calculated. With the information of the spectrum it was calculated the average energy of the neutrons of each source. By means of the fluence coefficients to dose it was determined, for each one of the studied sources, the fluence factors to dose. The calculated doses were H, H{sup *}(10), H{sub p,sIab} (10, 0{sup 0}), E{sub AP} and E{sub ISO}. During the phase of the calculations the sources were modeled as punctual and their characteristics were determined to 100 cm in the hole. Also, for the case of the sources of {sup 239} Pu Be and {sup 241} Am Be, were carried out calculations modeling the sources with their respective characteristics and the dosimetric properties were determined in a space full with air. The results of this last phase of the calculations were compared with the experimental results obtained for both sources. (Author)

  19. 48 CFR 52.211-16 - Variation in Quantity.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Variation in Quantity. 52....211-16 Variation in Quantity. As prescribed in 11.703(a), insert the following clause: Variation in Quantity (APR 1984) (a) A variation in the quantity of any item called for by this contract will not...

  20. Development of the Nation-Wide Dosimetric Monitoring Network in Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Chumak, V.; Boguslavskaya, A.; Musijachenko, A.

    2004-07-01

    Development of the nation-wide network for monitoring and registration of individual doses is being in progress in Ukraine. The need for urgent action is caused by the fact, that despite wide use of nuclear energy and radiation sources in industry and medicine, there is no centralized dose accounting system in Ukraine, existing dosimetry services operate obsolete manual TLD readers and no methodological unity is observed by the dosimetry services. Presently the mixed dosimetric monitoring is practiced in Ukraine. Nuclear power plants and some major nuclear facilities have their own dosimetry services responsible for dosimetric monitoring of workers. Rest of occupationally exposed persons is monitored by territorial dosimetry laboratories affiliated to sanitary and epidemiology supervision bodies. In total these services cover about 38,000 occupationally exposed workers, including 5,500 in medicine, 16,400 employees of five nuclear power plants and about 16,000 workers dealing with other sources of occupational exposure (industry, research, military). It is prescribed by the governmental decree that three-level united state system assigned to covering all aspects of efficient dosimetric monitoring should be established. The tasks of the system, in particular, are: securing methodical unity of individual dosimetric monitoring; scientific and methodological guidance of individual dosimetric control; procurement of common technical policy regarding nomenclature and operation of instrumentation; implementation of quality assurance programs; development and support of information infrastructure for logging, storage and access to data on individual dosimetric monitoring, in particular - keeping the national registry of individual doses; training and certification of personnel engaged in the system of individual dosimetric monitoring. In its development, the national system will be guided by international experience and will be established according to the best practices

  1. Dosimetric characterization and application of an imaging beam line with a carbon electron target for megavoltage cone beam computed tomography.

    Science.gov (United States)

    Flynn, Ryan T; Hartmann, Julia; Bani-Hashemi, Ali; Nixon, Earl; Alfredo, R; Siochi, C; Pennington, Edward C; Bayouth, John E

    2009-06-01

    Imaging dose from megavoltage cone beam computed tomography (MVCBCT) can be significantly reduced without loss of image quality by using an imaging beam line (IBL), with no flattening filter and a carbon, rather than tungsten, electron target. The IBL produces a greater keV-range x-ray fluence than the treatment beam line (TBL), which results in a more optimal detector response. The IBL imaging dose is not necessarily negligible, however. In this work an IBL was dosimetrically modeled with the Philips Pinnacle3 treatment planning system (TPS), verified experimentally, and applied to clinical cases. The IBL acquisition dose for a 200 degrees gantry rotation was verified in a customized acrylic cylindrical phantom at multiple imaging field sizes with 196 ion chamber measurements. Agreement between the measured and calculated IBL dose was quantified with the 3D gamma index. Representative IBL and TBL imaging dose distributions were calculated for head and neck and prostate patients and included in treatment plans using the imaging dose incorporation (IDI) method. Surface dose was measured for the TBL and IBL for four head and neck cancer patients with MOSFETs. The IBL model, when compared to the percentage depth dose and profile measurements, had 97% passing gamma indices for dosimetric and distance acceptance criteria of 3%, 3 mm, and 100% passed for 5.2%, 5.2 mm. For the ion chamber measurements of phantom image acquisition dose, the IBL model had 93% passing gamma indices for acceptance criteria of 3%, 3 mm, and 100% passed for 4%, 4 mm. Differences between the IBL- and TBL-based IMRT treatment plans created with the IDI method were dosimetrically insignificant for both the prostate and head and neck cases. For IBL and TBL beams with monitor unit values that would result in the delivery of the same dose to the depth of maximum dose under standard calibration conditions, the IBL imaging surface dose was higher than the TBL imaging surface dose by an average of 18

  2. Conformal invariance conserved quantity of Hamilton systems

    Institute of Scientific and Technical Information of China (English)

    Cai Jian-Le; Luo Shao-Kai; Mei Feng-Xiang

    2008-01-01

    This paper studies conformal invariance and comserved quantRies of Hamilton system.The definition and the determining equation of conformal invariance for Hamilton system are provided.The relationship between the conformal invariance and the Lie symmetry are discussed,and the necessary and sufficient condition that the conformal invariance would be the Lie symmetry of the system under the infinitesimal one-parameter transformation group is deduced.It gives the conserved quantities of the system and an example for illustration.

  3. On ADM quantities of multiple black holes

    CERN Document Server

    Rácz, István

    2016-01-01

    In [11] a proposal was made to construct initial data for binary black hole configurations. It was done by using the parabolic-hyperbolic form of the constraints and choosing the free data provided by superposed Kerr-Schild black holes. The proposal of [11] do also apply to multiple systems involving generic Kerr-Schild black holes. Notably, the specific choice made for the free data allows---without making detailed use of the to be solutions to the constraints---to determine explicitly, the ADM quantities of the multiple system in terms of the separations velocities and spins of the individual Kerr-Schild black holes.

  4. Dosimetric characteristics of four PTW microDiamond detectors in high-energy proton beams

    Science.gov (United States)

    Marsolat, F.; De Marzi, L.; Patriarca, A.; Nauraye, C.; Moignier, C.; Pomorski, M.; Moignau, F.; Heinrich, S.; Tromson, D.; Mazal, A.

    2016-09-01

    Small diamond detectors are useful for the dosimetry of high-energy proton beams. However, linear energy transfer (LET) dependence has been observed in the literature with such solid state detectors. A novel synthetic diamond detector has recently become commercially available from the manufacturer PTW-Freiburg (PTW microDiamond type 60019). This study was designed to thoroughly characterize four microDiamond detectors in clinical proton beams, in order to investigate their response and their reproducibility in high LET regions. Very good dosimetric characteristics were observed for two of them, with good stability of their response (deviation less than 0.4% after a pre-irradiation dose of approximately 12 Gy), good repeatability (coefficient of variation of 0.06%) and a sensitivity of approximately 0.85 nC Gy-1. A negligible dose rate dependence was also observed for these two microDiamonds with a deviation of the sensitivity less than 0.7% with respect to the one measured at the reference dose rate of 2.17 Gy min-1, in the investigated dose rate range from 1.01 Gy min-1 to 5.52 Gy min-1. Lateral dose profile measurements showed the high spatial resolution of the microDiamond oriented with its stem perpendicular to the beam axis and with its small sensitive thickness of about 1 μm in the scanning profile direction. Finally, no significant LET dependence was found with these two diamond dosimeters in comparison to a reference ionization chamber (model IBA PPC05). These good results were in accordance to the literature. However, this study showed also a non reproducibility between the devices in terms of stability, sensitivity and LET dependence, since the two other microDiamonds characterized in this work showed different dosimetric characteristics making them not suitable for proton beam dosimetry with a maximum difference of the peak-to-plateau ratio of 6.7% relative to the reference ionization chamber in a clinical 138 MeV proton beam.

  5. Dosimetric studies of anti-CD20 labeled with therapeutic radionuclides at IPEN/CNEN-SP

    Energy Technology Data Exchange (ETDEWEB)

    Barrio, G.; Dias, C.R.B.R.; Osso Junior, J.A., E-mail: gracielabarrio@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-07-01

    Radioimmunotherapy (RIT) makes use of monoclonal antibodies (MAb) labeled with alpha/beta radionuclides for therapeutical purposes, leading to tumor irradiation and destruction, preserving the normal organs on the radiation excess. The therapeutic activity to be injected in a specific patient is based on information obtained in dosimetric studies. Beta emitting radionuclides such as {sup 131}I, {sup 188}Re, {sup 90}Y, {sup 177}Lu and {sup 166}Ho are useful for the development of therapeutic radiopharmaceuticals. Anti-CD20 (Rituximab) is a chimeric MAb directed against antigen surface CD20 on B-lymphocytes, used in non-Hodgkin lymphoma treatment (NHL). The association with beta radionuclides have shown greater therapeutic efficacy. Currently, two radiopharmaceuticals with Anti-CD20 for radioimmunotherapy have FDA approval for NHL treatment: {sup 131}I-AntiCD20 (Bexar) and {sup 90}Y-AntiCD20 (Zevalin). Techniques for the radiolabeling of {sup 188}Re-antiCD20 have been recently developed by IPEN-CNEN/SP in order to evaluate the clinical use of this radionuclide in particular. The use of {sup 188}Re (T{sub 1/2} 17h) produced by the decay of {sup 188}W (T{sub 1/2} 69d), from an {sup 188}W/{sup 188}Re generator system, has represented an alternative to RIT. Beyond high energy beta emission for therapy, {sup 188}Re also emits gamma rays (155keV) suitable for image. The aim of this new project is to compare the labeling of anti-CD20 with {sup 188}Re with the same MAb labeled with {sup 131}I, {sup 177}Lu, {sup 90}Y and even {sup 99m}Tc. The first step in this project is the review of the published data available concerning the labeling of this MAb with different radionuclides, along with data obtained at IPEN, taking into account labeling procedures, labeling yields, reaction time, level and kind of impurities and biodistribution studies. The pharmacokinetic code will be developed in Visual Studio.NET platform through VB.NET and C{sup ++} for biodistribution and dosimetric

  6. Effect of endorectal balloon positioning errors on target deformation and dosimetric quality during prostate SBRT

    Science.gov (United States)

    Jones, Bernard L.; Gan, Gregory; Kavanagh, Brian; Miften, Moyed

    2013-11-01

    An inflatable endorectal balloon (ERB) is often used during stereotactic body radiation therapy (SBRT) for treatment of prostate cancer in order to reduce both intrafraction motion of the target and risk of rectal toxicity. However, the ERB can exert significant force on the prostate, and this work assessed the impact of ERB position errors on deformation of the prostate and treatment dose metrics. Seventy-one cone-beam computed tomography (CBCT) image datasets of nine patients with clinical stage T1cN0M0 prostate cancer were studied. An ERB (Flexi-Cuff, EZ-EM, Westbury, NY) inflated with 60 cm3 of air was used during simulation and treatment, and daily kilovoltage (kV) CBCT imaging was performed to localize the prostate. The shape of the ERB in each CBCT was analyzed to determine errors in position, size, and shape. A deformable registration algorithm was used to track the dose received by (and deformation of) the prostate, and dosimetric values such as D95, PTV coverage, and Dice coefficient for the prostate were calculated. The average balloon position error was 0.5 cm in the inferior direction, with errors ranging from 2 cm inferiorly to 1 cm superiorly. The prostate was deformed primarily in the AP direction, and tilted primarily in the anterior-posterior/superior-inferior plane. A significant correlation was seen between errors in depth of ERB insertion (DOI) and mean voxel-wise deformation, prostate tilt, Dice coefficient, and planning-to-treatment prostate inter-surface distance (p < 0.001). Dosimetrically, DOI is negatively correlated with prostate D95 and PTV coverage (p < 0.001). For the model of ERB studied, error in ERB position can cause deformations in the prostate that negatively affect treatment, and this additional aspect of setup error should be considered when ERBs are used for prostate SBRT. Before treatment, the ERB position should be verified, and the ERB should be adjusted if the error is observed to exceed tolerable values.

  7. A standard Fricke dosimeter compared to an ionization chamber used for dosimetric characterization of 60Co photon beam

    Science.gov (United States)

    Moussous, Ouiza; Medjadj, Toufik

    2016-06-01

    The main objective of this study was to investigate the Fricke dosimeter water equivalent system for measurement of dosimetric parameters for photon beam. The parameters measured with the Fricke dosimeter were compared to those obtained with an ionization chamber. In this work characteristics for 60Co γ-rays of field sizes ranging from 5 × 5 cm2 to 20 × 20 cm2 are reported. The measurements were carried out in the secondary standard dosimetry laboratory using a collimated 60Co gamma source therapy unit. The 60Co beam output in terms of absorbed dose to water was obtained as per IAEA TRS 398 recommendations using cylindrical ionization chamber, whose ND,w has been supplied by the IAEA's reference laboratory. Specific quantities measured include: output factors, peak scatter factor, lateral beam profiles and percentage depth dose. The Fricke dosimeters were irradiated in a water phantom using the suitable poly (methyl methacrylate), PMMA stand. Our results demonstrate that Fricke dosimeter and ionization chamber agree with each other.

  8. Dosimetry study of PHOTOFRIN-mediated photodynamic therapy in a mouse tumor model

    Science.gov (United States)

    Qiu, Haixia; Kim, Michele M.; Penjweini, Rozhin; Zhu, Timothy C.

    2016-03-01

    It is well known in photodynamic therapy (PDT) that there is a large variability between PDT light dose and therapeutic outcomes. An explicit dosimetry model using apparent reacted 1O2 concentration [1O2]rx has been developed as a PDT dosimetric quantity to improve the accuracy of the predicted ability of therapeutic efficacy. In this study, this explicit macroscopic singlet oxygen model was adopted to establish the correlation between calculated reacted [1O2]rx and the tumor growth using Photofrin-mediated PDT in a mouse tumor model. Mice with radiation-induced fibrosarcoma (RIF) tumors were injected with Photofrin at a dose of 5 mg/kg. PDT was performed 24h later with different fluence rates (50, 75 and 150 mW/cm2) and different fluences (50 and 135 J/cm2) using a collimated light applicator coupled to a 630nm laser. The tumor volume was monitored daily after PDT and correlated with the total light fluence and [1O2]rx. Photophysical parameters as well as the singlet oxygen threshold dose for this sensitizer and the RIF tumor model were determined previously. The result showed that tumor growth rate varied greatly with light fluence for different fluence rates while [1O2]rx had a good correlation with the PDT-induced tumor growth rate. This preliminary study indicated that [1O2]rx could serve as a better dosimetric predictor for predicting PDT outcome than PDT light dose.

  9. Dosimetric properties of improved GafChromic films for seven different digitizers.

    Science.gov (United States)

    Devic, Slobodan; Seuntjens, Jan; Hegyi, Gyorgy; Podgorsak, Ervin B; Soares, Christopher G; Kirov, Assen S; Ali, Imad; Williamson, Jeffrey F; Elizondo, Angel

    2004-09-01

    Two recently introduced GafChromic film models, HS and XR-T, have been developed as more sensitive and uniform alternatives to GafChromic MD-55-2 film. The HS model has been specifically designed for measurement of absorbed dose in high-energy photon beams (above 1 MeV), while the XR-T model has been introduced for dose measurements of low energy (0.1 MeV) photons. The goal of this study is to compare the sensitometric curves and estimated dosimetric uncertainties associated with seven different GafChromic film dosimetry systems for the two new film models. The densitometers tested are: LKB Pharmacia UltroScan XL, Molecular Dynamics Personal Densitometer, Nuclear Associates Radiochromic Densitometer Model 37-443, Photoelectron Corporation CMR-604, Laser Pro 16, Vidar VXR-16, and AGFA Arcus II document scanner. Pieces of film were exposed to different doses in a dose range from 0.5 to 50 Gy using 6 MV photon beam. Functional forms for dose vs net optical density have been determined for each of the GafChromic film-dosimetry systems used in this comparison. Two sources of uncertainties in dose measurements, governed by the experimental measurement and calibration curve fit procedure, have been compared for the densitometers used. Among the densitometers tested, it is found that for the HS film type the uncertainty caused by the experimental measurement varies from 1% to 3% while the calibration fit uncertainty ranges from 2% to 4% for doses above 5 Gy. Corresponding uncertainties for XR-T film model are somewhat higher and range from 1% to 5% for experimental and from 2% to 7% for the fit uncertainty estimates. Notwithstanding the significant variations in sensitivity, the studied densitometers exhibit very similar precision for GafChromic film based dose measurements above 5 Gy.

  10. Preliminary dosimetric methodology for a new cobalt-60 irradiator for radioinduced necrosis

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Eduardo S.; Mosca, Rodrigo C.; Zeituni, Carlos A.; Rostelato, Maria Elisa C.M.; Mathor, Monica B., E-mail: esmoura@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Sakuraba, Roberto K.; Goncalves, Vinicius D. [Hospital Israelita Albert Einstein (HIAE), Sao Paulo, SP (Brazil)

    2011-07-01

    The use of ionizing radiation in medical procedures, as radiotherapy, is a well-established clinical process and it has been used for several decades with good clinical results and continuous technology development for treatment optimization. On the contrary, some injuries such as necrosis, may occur with patients, due to wrong administration of the absorbed dose or with expected side effects. To evaluate how these injuries could be investigated and how they can be treated, a new Cobalto-60 irradiator was developed to induce radionecrosis in mice. This irradiator is composed by a cylindrical size and it was set up with eleven Cobalt-60 sources aligned in the surface of a cylindrical lead. This alignment guarantees a small dose focal area in a longitudinal table, with proper frames for positioning mice precisely during the irradiations period. The dosimetric procedure will measure the absorbed dose in the dose focal area, delimited the area of irradiation with penumbra regions (gradients absorbed dose profiles) and others anatomical regions of the mice with high radiosensitivity. Possible dosimetric procedures and related devices will be present in this work,. The obtained dosimetric data will be applied to ensure the accurate period of radiation of a given position. This preliminary study assures that the fundamental dosimetric process of this new Cobalt-60 irradiator and it predicates that dosimetric processes area feasible to be conducted. (author)

  11. A dosimetric evaluation of flattening filter-free volumetric modulated arc therapy in nasopharyngeal carcinoma

    Directory of Open Access Journals (Sweden)

    Guishan Fu

    2014-01-01

    Full Text Available Purpose: To explore the dosimetric effects of flattening filter-free (FFF beams in volumetric modulated arc therapy (VMAT of nasopharyngeal carcinoma via a retrospective planning study. Materials and Methods: A linear accelerator (LINAC was prepared to operate in FFF mode and the beam data were collected and used to build a model in TPS. For 10 nasopharyngeal carcinoma (NPC cases, VMAT plans of FFF beams and normal flattened (FF beams were designed. Differences of plan quality and delivery efficiency between FFF-VMAT plans and filter filtered VMAT (FF-VMAT plans were analyzed using two-tailed paired t-tests. Results: Removal of the flattening filter increased the dose rate. Averaged beam on time (BOT of FFF-VMAT plans was decreased by 24.2%. Differences of target dose coverage between plans with flattened and unflattened beams were statistically insignificant. For dose to normal organs, up to 4.9% decrease in V35 of parotid grand and 4.5% decrease in averaged normal tissue (NT dose was observed. Conclusions: The TPS used in our study was able to handle FFF beams. The FFF beam prone to improve the normal tissue sparing while achieving similar target dose distribution. Decreasing of BOT in NPC cases was valuable in terms of patient′s comfort.

  12. High spatial resolution dosimetric response maps for radiotherapy ionization chambers measured using kilovoltage synchrotron radiation

    Science.gov (United States)

    Butler, D. J.; Stevenson, A. W.; Wright, T. E.; Harty, P. D.; Lehmann, J.; Livingstone, J.; Crosbie, J. C.

    2015-11-01

    Small circular beams of synchrotron radiation (0.1 mm and 0.4 mm in diameter) were used to irradiate ionization chambers of the types commonly used in radiotherapy. By scanning the chamber through the beam and measuring the ionization current, a spatial map of the dosimetric response of the chamber was recorded. The technique is able to distinguish contributions to the large-field ionization current from the chamber walls, central electrode and chamber stem. Scans were recorded for the NE 2571 Farmer chamber, the PTW 30013, IBA FC65-G Farmer-type chambers, the NE 2611A and IBA CC13 thimble chambers, the PTW 31006 and 31014 pinpoint chambers, the PTW Roos and Advanced Markus plane-parallel chambers, and the PTW 23342 thin-window soft x-ray chamber. In all cases, large contributions to the response arise from areas where the incident beam grazes the cavity surfaces. Quantitative as well as qualitative information about the relative chamber response was extracted from the maps, including the relative contribution of the central electrode. Line scans using monochromatic beams show the effect of the photon energy on the chamber response. For Farmer-type chambers, a simple Monte Carlo model was in good agreement with the measured response.

  13. Dosimetric study of photobiomodulation therapy in 5-FU-induced oral mucositis in hamsters

    Science.gov (United States)

    Cotomacio, Claudia Carrara; Campos, Luana; Nesadal de Souza, Douglas; Arana-Chavez, Victor Elias; Simões, Alyne

    2017-01-01

    Oral mucositis (OM) is a debilitating consequence of cancer treatment that could be treated with photobiomodulation therapy (PBMT); however, there is no consensus about its dosimetric parameters for OM healing. The aim of this study was to compare different PBMT protocols on OM treatment, through clinical and histological analysis. Thirty hamsters were used, in an induced model of OM by 5-fluorouracil (5-FU) and superficial scratching, in seven days of follow-up. The animals were divided into five groups: control (C), which received only anesthesia and chemotherapeutic vehicle; chemotherapy (Ch), which received anesthesia, 5-FU, and scratches; laser 1 (L1), the same as Ch group, PBMT 6 J/cm2 and 0.24 J (one point); laser 2 (L2), the same as Ch group, PBMT 25 J/cm2 and 1 J (one point); and laser 3 (L3), the same as Ch group, PBMT 4 points of 0.24 J and 6 J/cm2 each. The laser used has λ=660 nm, 0.04 cm2 of spot area, and 40 mW. The best PBMT protocol to maintain lowest OM levels compared to Ch group was L1, followed by L2 and L3. Our results suggest that the application mode of PBMT and the energy delivered per area could interfere with the OM healing.

  14. Monte Carlo calculations and experimental measurements of dosimetric parameters of the IRA-103Pd brachytherapy source.

    Science.gov (United States)

    Sadeghi, Mahdi; Raisali, Gholamreza; Hosseini, S Hamed; Shavar, Arzhang

    2008-04-01

    This article presents a brachytherapy source having 103Pd adsorbed onto a cylindrical silver rod that has been developed by the Agricultural, Medical, and Industrial Research School for permanent implant applications. Dosimetric characteristics (radial dose function, anisotropy function, and anisotropy factor) of this source were experimentally and theoretically determined in terms of the updated AAPM Task group 43 (TG-43U1) recommendations. Monte Carlo simulations were used to calculate the dose rate constant. Measurements were performed using TLD-GR200A circular chip dosimeters using standard methods employing thermoluminescent dosimeters in a Perspex phantom. Precision machined bores in the phantom located the dosimeters and the source in a reproducible fixed geometry, providing for transverse-axis and angular dose profiles over a range of distances from 0.5 to 5 cm. The Monte Carlo N-particle (MCNP) code, version 4C simulation techniques have been used to evaluate the dose-rate distributions around this model 103Pd source in water and Perspex phantoms. The Monte Carlo calculated dose rate constant of the IRA-103Pd source in water was found to be 0.678 cGy h(-1) U(-1) with an approximate uncertainty of +/-0.1%. The anisotropy function, F(r, theta), and the radial dose function, g(r), of the IRA- 103Pd source were also measured in a Perspex phantom and calculated in both Perspex and liquid water phantoms.

  15. Cellular uptake of {sup 212}BiOCl by Ehrlich ascites cells: A dosimetric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Roeske, J.C.; Whitlock, J.L.; Harper, P.V.; Rotmensch, J. [Univ. of Chicago, IL (United States); Stinchcomb, T.G. [DePaul Univ., Chicago, IL (United States). Dept. of Physics; Schwartz, J.L. [Univ. of Washington, Seattle, WA (United States). Dept. of Radiation Oncology; Hines, J.J. [Argonne National Lab., IL (United States). Chemistry Div.

    1999-01-01

    Bi-212 is an alpha-emitting radionuclide being investigated as a therapeutic agent in the intraperitoneal treatment of micrometastatic ovarian carcinoma. In evaluating a new therapeutic modality, cell-survival studies are often used as a means of quantifying the biological effects of radiation. In this analysis, Ehrlich ascites cells were irradiated under conditions similar to therapy in various concentrations of Bi-212. Immediately following irradiation, a cell survival assay was performed in which cells were plated and colonies were counted after 10--14 days. Both a macrodosimetric and a microdosimetric approach were used in analyzing these data. These models used as input the fraction of activity within the cell and in solution, the distribution of cell sizes, and the variation of LET along individual alpha-particle tracks. The results indicate that the energy deposited within the nucleus varies significantly among individual cells. There is a small fraction of cell nuclei which receive no hits, while the remaining cells receive energy depositions which can differ significantly from the mean value. These dosimetric parameters are correlated with measured cell survival and will be a useful predictor of outcome for therapeutic doses.

  16. Application of optimisation techniques in groundwater quantity and quality management

    Indian Academy of Sciences (India)

    Amlan Das; Bithin Datta

    2001-08-01

    This paper presents the state-of-the-art on application of optimisation techniques in groundwater quality and quantity management. In order to solve optimisation-based groundwater management models, researchers have used various mathematical programming techniques such as linear programming (LP), nonlinear programming (NLP), mixed-integer programming (MIP), optimal control theory-based mathematical programming, differential dynamic programming (DDP), stochastic programming (SP), combinatorial optimisation (CO), and multiple objective programming for multipurpose management. Studies reported in the literature on the application of these methods are reviewed in this paper.

  17. Characteristic limits of two dosimetric systems used in individual monitoring; Limites caracteristicos de dois sistemas dosimetricos utilizados em monitoracao individual

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, L.S.; Meira-Belo, L.C.; Lacerda, M.A.S., E-mail: masl@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Oliveira, P.M.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil)

    2014-07-01

    The characteristic limits: Decision Threshold (y⁎*), Detection Limit (y⧣) and Limits of the Confidence Interval ( y ⊲ and y⊳), were determined for two TLD-100 dosimetric systems, used for individual monitoring. We perform a critical analysis of the suitability of utilizing a dosimetric system for low dose range applications, based on these characteristic values. (author)

  18. Effective dose: a radiation protection quantity

    CERN Document Server

    Menzel, H G

    2012-01-01

    Modern radiation protection is based on the principles of justification, limitation, and optimisation. Assessment of radiation risks for individuals or groups of individuals is, however, not a primary objective of radiological protection. The implementation of the principles of limitation and optimisation requires an appropriate quantification of radiation exposure. The International Commission on Radiological Protection (ICRP) has introduced effective dose as the principal radiological protection quantity to be used for setting and controlling dose limits for stochastic effects in the regulatory context, and for the practical implementation of the optimisation principle. Effective dose is the tissue weighted sum of radiation weighted organ and tissue doses of a reference person from exposure to external irradiations and internal emitters. The specific normalised values of tissue weighting factors are defined by ICRP for individual tissues, and used as an approximate age- and sex-averaged representation of th...

  19. Dosimetric impact assessment using a general algorithm in geant4 simulations for a complex-shaped multileaf collimator.

    Science.gov (United States)

    Perales, Á; Cortés-Giraldo, M A; Miras, H; Arráns, R; Gallardo, M I

    2017-04-07

    We have developed an inhouse algorithm for the multileaf collimator (MLC) geometry model construction with an appropriate accuracy for dosimetric tests. Our purpose is to build a complex type of MLC and analyze the influence of the modeling parameters on the dose calculation. Using radiochromic films as detector the following tests were done: (I) Density test field: to compare measured and calculated dose distributions in order to determine the tungsten alloy physical density value. (II) Leaf ends test field: to verify the penumbra shape sensitivity against the discretization level set to simulate the curved leaf ends. (III) MLC-closed field: to obtain the value of the air gap between opposite leaves for a closed configuration which completes the modeling of the MLC leakage radiation. (IV) Picket-fence field: to fit the leaf tilt angle with respect of the divergent ray emerging from the source. For a 18.5g/cm(3) density value we have obtained a maximum, minimum and mean leakage values of 0.43%, 0.36% and 0.38%, similar to the experimental ones. The best discretization level in the leaf ends field shows a 5.51mm FWHM, very close to the measured value (5.49mm). An air gap of 370μm has been used in the simulation for the separation between opposite leaves. Using a 0.44° tilt angle, we found the same pattern as the experimental values. Our code can reproduce complex MLC designs with a submilimetric dosimetric accuracy which implies the necessary background for dose calculation of high clinical interest small fields. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  20. A linear programming model for optimizing HDR brachytherapy dose distributions with respect to mean dose in the DVH-tail

    Energy Technology Data Exchange (ETDEWEB)

    Holm, Åsa; Larsson, Torbjörn [Department of Mathematics, Linköping University, SE-581 83 Linköping (Sweden); Tedgren, Åsa Carlsson [Department of Medical and Health Sciences, Radiation Physics, Linköping University, SE 581-83 Linköping, Sweden and Swedish Radiation Safety Authority, SE-171 16 Stockholm (Sweden)

    2013-08-15

    Purpose: Recent research has shown that the optimization model hitherto used in high-dose-rate (HDR) brachytherapy corresponds weakly to the dosimetric indices used to evaluate the quality of a dose distribution. Although alternative models that explicitly include such dosimetric indices have been presented, the inclusion of the dosimetric indices explicitly yields intractable models. The purpose of this paper is to develop a model for optimizing dosimetric indices that is easier to solve than those proposed earlier.Methods: In this paper, the authors present an alternative approach for optimizing dose distributions for HDR brachytherapy where dosimetric indices are taken into account through surrogates based on the conditional value-at-risk concept. This yields a linear optimization model that is easy to solve, and has the advantage that the constraints are easy to interpret and modify to obtain satisfactory dose distributions.Results: The authors show by experimental comparisons, carried out retrospectively for a set of prostate cancer patients, that their proposed model corresponds well with constraining dosimetric indices. All modifications of the parameters in the authors' model yield the expected result. The dose distributions generated are also comparable to those generated by the standard model with respect to the dosimetric indices that are used for evaluating quality.Conclusions: The authors' new model is a viable surrogate to optimizing dosimetric indices and quickly and easily yields high quality dose distributions.

  1. Medical Dosimetric Registry of Russian Atomic Industry Employees: Current Status and Perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Ilyin, L. A.; Kiselev, M. F.; Panfilov, A. P.; Kochetkov, O. A.; Ivanov, A. A.; Grinev, M. P.; Soloviev, V. Y.; Semenov, V. G.; Tukov, A. R.; Koshuurnikova, N. A.; Takhauov, R. M.; Melnikov, G. Y.

    2004-07-01

    Epidemiological studies of nuclear industry personnel contain the significant abilities to assess the prolonged radiation exposure effects in the human health. The clarification of these assessments and following improvements of the scientific justification of radiation regulation require the expansion of factual basis of the research currently, Branch Medical Dosimetric Registry (BMDR) of atomic industry and nuclear power employees is under the development in Russian to compose a number of regional registries. This work is coordinated by the State Research Center- Institute of Biophysics (Moscow). The first phase of this project was devoted to the forming of the regional registry of Mayak PA employees (Ozersk, South Uranl region). the employee registries of Siberian Chemical Plant (SCP, Seversk, Tomsk region) and Mountain Chemical Plant (MCP, Zheleznogorsk, Krasnoyarsk region) are at the finalization. At later phases, BMDR will be added by the information on other enterprises and on operating NPP too. The paper describes the structure, general issues of the forming and current status of BMDR. The comparison of major BMDR features versus LSS registry (which is the one of basic components for international radiation protection recommendations and current radiation protection standards) demonstrates that BMDR information can be more preferable to assess the significance of the man made radiation at high and intermediate dose ranges. Particularly, the number of employees (20-40 year age range) exposed to doses specific to detectable radiation health effects (above 2000 mSv) is almost ten times more than that for LSS cohort. Besides, the health monitoring was elaborated since the employment start point (Whereas, since year 5 for LSS cohort). BMDR dose records were measured (against LSS reconstructed doses) and the employee exposure duration was equal to years and decade (alternatively to momentary exposure recorded in LSS). BMDR data quantity and quality correspond to

  2. A new proposal on the operational quantity H{sub p}(3): Monte Carlo and experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Mariotti, F., E-mail: francesca.mariotti@bologna.enea.i [ENEA Radiation Protection Institute, Via dei Colli 16, 40136 Bologna (Italy); Gualdrini, G.; Fantuzzi, E.; Ferrari, P.; Monteventi, F. [ENEA Radiation Protection Institute, Via dei Colli 16, 40136 Bologna (Italy)

    2011-04-15

    The European Union is funding the ORAMED Contract (Optimization of RAdiation protection for MEDical staff) project that aims at developing methodologies for better assessing and reducing exposures to medical staff for procedures resulting in potentially large doses or complex radiation fields, such as interventional radiology, nuclear medicine and new developments. One of the ORAMED Working Tasks is addressed to the discussion and implementation in the radiation protection practice of the eye lens equivalent dose. The aim of this task group is to develop a personal dosemeter characterized in term of H{sub p}(3). Until now H{sub p}(3) conversion coefficients were not reported in the official recommendations and the available data were calculated for a 30 x 30 x 15 cm{sup 3} slab phantom that is far away to represent the head. A reduced slab phantom, for both calculating the quantities and type testing personal dosemeter in terms of the operational quantity, was previously proposed by ENEA Bologna team. The study demonstrated that a reduced slab phantom is better representative of a real situation, but the angular dependence of H{sub p}(3,{alpha}) due to the edges of the slab reduces its applicability. Therefore a better-suited phantom is proposed here. The dosimetric assessment in terms of this quantity is seldom performed in the various workplaces (e.g. hospitals) and therefore a question rises about its usefulness and practical implementation. The present work tries to introduce new elements in the discussion on the quantity H{sub p}(3) and to propose a more suitable theoretical cylindrical phantom (and a corresponding experimental one for the calibration procedures) to better approximate the head in which the eyes are placed.

  3. Transport and dosimetric solutions for the ELIMED laser-driven beam line

    Energy Technology Data Exchange (ETDEWEB)

    Cirrone, G.A.P. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Romano, F. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Medical Physics School, University of Catania, Via S. Sofia 64 - 95125 Catania (Italy); Scuderi, V. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, Na Slovance 2, 182 21 Prague (Czech Republic); Amato, A. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Candiano, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Medical Physics School, University of Catania, Via S. Sofia 64 - 95125 Catania (Italy); Cuttone, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Giove, D. [INFN Sezione di Milano, Via Celoria 16, Milano (Italy); Korn, G.; Krasa, J. [Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, Na Slovance 2, 182 21 Prague (Czech Republic); Leanza, R. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Universitá degli Studi di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Manna, R. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Maggiore, M. [INFN-LNL, Viale dell' Universitá 2 - 35020 Legnaro (PD) (Italy); Marchese, V. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Margarone, D. [Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, Na Slovance 2, 182 21 Prague (Czech Republic); Milluzzo, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Universitá degli Studi di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Petringa, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Sabini, M.G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Azienda Ospedaliera Cannizzaro, Via Messina 829 - 95100 Catania (Italy); Schillaci, F. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Medical Physics School, University of Catania, Via S. Sofia 64 - 95125 Catania (Italy); and others

    2015-10-01

    Within 2017, the ELIMED (ELI-Beamlines MEDical applications) transport beam-line and dosimetric systems for laser-generated beams will be installed at the ELI-Beamlines facility in Prague (CZ), inside the ELIMAIA (ELI Multidisciplinary Applications of laser–Ion Acceleration) interaction room. The beam-line will be composed of two sections: one in vacuum, devoted to the collecting, focusing and energy selection of the primary beam and the second in air, where the ELIMED beam-line dosimetric devices will be located. This paper briefly describes the transport solutions that will be adopted together with the main dosimetric approaches. In particular, the description of an innovative Faraday Cup detector with its preliminary experimental tests will be reported.

  4. Approximated segmentation considering technical and dosimetric constraints in intensity-modulated radiation therapy with electrons

    CERN Document Server

    Kiesel, Antje

    2010-01-01

    In intensity-modulated radiation therapy, optimal intensity distributions of incoming beams are decomposed into linear combinations of leaf openings of a multileaf collimator (segments). In order to avoid inefficient dose delivery, the decomposition should satisfy a number of dosimetric constraints due to suboptimal dose characteristics of small segments. However, exact decomposition with dosimetric constraints is only in limited cases possible. The present work introduces new heuristic segmentation algorithms for the following optimization problem: Find a segmentation of an approximated matrix using only allowed fields and minimize the approximation error. Finally, the decomposition algorithms were implemented into an optimization programme in order to examine the assumptions of the algorithms for a clinical example. As a result, identical dose distributions with much fewer segments and a significantly smaller number of monitor units could be achieved using dosimetric constraints. Consequently, the dose deli...

  5. Dosimetric response of united, commercially available CTA foils for sup 6 sup 0 Co gamma rays

    CERN Document Server

    Peimel-Stuglik, Z

    2001-01-01

    The usefulness of two kinds of untinted CTA foils: Fuji CTR-125 dosimetric foil and technical CTA-T foil, produced by 'Zaklady Chemiczne, 'Gorzow Wielkopolski' as support for light-sensitive layers of amateur photo-films, for sup 6 sup 0 Co gamma ray dosimetry was investigated. In spite of rather bad physical parameters of the technical foil (spread of foil thickness, high and different initial absorbance) the dosimetric response of both foils for sup 6 sup 0 Co gamma rays was similar. The CTA-T foil can be used for routine dosimetry providing that dosimetric signals have to be calculated exactly as recommended by the ASTM (American Society for Testing and Materials) standard, i.e. as the difference of absorbance of irradiated and (the same) non-irradiated foil. Any other approach may lead to high errors of dose evaluation. The last is true also for other CTA foils, especially after long self-life.

  6. Monte Carlo dosimetric study of the BEBIG Co-60 HDR source

    Energy Technology Data Exchange (ETDEWEB)

    Ballester, F [Department of Atomic, Molecular and Nuclear Physics and IFIC, University of Valencia-CSIC, Dr Moliner 50, E46100 Burjassot (Spain); Granero, D [Department of Atomic, Molecular and Nuclear Physics and IFIC, University of Valencia-CSIC, Dr Moliner 50, E46100 Burjassot (Spain); Perez-Calatayud, J [' La Fe' University Hospital, Radiotherapy Department, Avda Campanar 21, E46009 Valencia (Spain); Casal, E [Department of Atomic, Molecular and Nuclear Physics and IFIC, University of Valencia-CSIC, Dr Moliner 50, E46100 Burjassot (Spain); Agramunt, S [ITIC, Hospital ClInica Benidorm, Avd. Alfonso Puchades 8, E03500 Benidorm (Spain); Cases, R [Department of Atomic, Molecular and Nuclear Physics and IFIC, University of Valencia-CSIC, Dr Moliner 50, E46100 Burjassot (Spain)

    2005-11-07

    Although not as widespread as Ir-192, Co-60 is also available on afterloading equipment devoted to high dose rate brachytherapy, mainly addressed to the treatment of gynaecological lesions. The purpose of this study is to obtain the dosimetric parameters of the Co-60 source used by the BEBIG MultiSource remote afterloader (BEBIG GmbH, Germany) for which there are no dosimetric data available in the literature. The Monte Carlo code GEANT4 has been used to obtain the TG43 parameters and the 2D dose rate table in Cartesian coordinates of the BEBIG Co-60 HDR source. The dose rate constant, radial dose function and anisotropy function have been calculated and are presented in a tabular form as well as a detailed 2D dose rate table in Cartesian coordinates. These dosimetric datasets can be used as input data and to validate the treatment planning system calculations. (note)

  7. NOTE: Monte Carlo dosimetric study of the BEBIG Co-60 HDR source

    Science.gov (United States)

    Ballester, F.; Granero, D.; Pérez-Calatayud, J.; Casal, E.; Agramunt, S.; Cases, R.

    2005-11-01

    Although not as widespread as Ir-192, Co-60 is also available on afterloading equipment devoted to high dose rate brachytherapy, mainly addressed to the treatment of gynaecological lesions. The purpose of this study is to obtain the dosimetric parameters of the Co-60 source used by the BEBIG MultiSource remote afterloader (BEBIG GmbH, Germany) for which there are no dosimetric data available in the literature. The Monte Carlo code GEANT4 has been used to obtain the TG43 parameters and the 2D dose rate table in Cartesian coordinates of the BEBIG Co-60 HDR source. The dose rate constant, radial dose function and anisotropy function have been calculated and are presented in a tabular form as well as a detailed 2D dose rate table in Cartesian coordinates. These dosimetric datasets can be used as input data and to validate the treatment planning system calculations.

  8. Theoretical dosimetric evaluation of carbon and oxygen minibeam radiation therapy.

    Science.gov (United States)

    González, Wilfredo; Peucelle, Cécile; Prezado, Yolanda

    2017-05-01

    Charged particles have several advantages over x-ray radiations, both in terms of physics and radiobiology. The combination of these advantages with those of minibeam radiation therapy (MBRT) could help enhancing the therapeutic index for some cancers with poor prognosis. Among the different ions explored for therapy, carbon ions are considered to provide the optimum physical and biological characteristics. Oxygen could be advantageous due to a reduced oxygen enhancement ratio along with a still moderate biological entrance dose. The aforementioned reasons justified an in-depth evaluation of the dosimetric features of carbon and oxygen minibeam radiation therapy to establish the interest of further explorations of this avenue. The GATE/Geant4 6.2 Monte Carlo simulation platform was employed to simulate arrays of rectangular carbon and oxygen minibeams (600 μm × 2 cm) at a water phantom entrance. They were assumed to be generated by means of a magnetic focusing. The irradiations were performed with a 2-cm-long spread-out Bragg peak (SOBP) centered at 7-cm-depth. Several center-to-center (c-t-c) distances were considered. Peak and valley doses, as well as peak-to-valley dose ratio (PVDR) and the relative contribution of nuclear fragments and electromagnetic processes were assessed. In addition, the type and proportion of the secondary nuclear fragments were evaluated in both peak and valley regions. Carbon and oxygen MBRT lead to very similar dose distributions. No significant advantage of oxygen over carbon ions was observed from physical point of view. Favorable dosimetric features were observed for both ions. Thanks to the reduced lateral scattering, the standard shape of the depth dose curves (in the peaks) is maintained even for submillimetric beam sizes. When a narrow c-t-c is considered (910-980 μm), a (quasi) homogenization of the dose can be obtained at the target, while a spatial fractionation of the dose is maintained in the proximal normal tissues with

  9. Dosimetric predictors of diarrhea during radiotherapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sanguineti, Giuseppe [Radiation Oncology, Univ. of Texas Medical Branch, Galveston, TX (United States); Endres, Eugene J.; Parker, Brent C. [Physics Dept., Univ. of Texas Medical Branch, Galveston, TX (United States); Sormani, Maria Pia [Biostatistics Unit, Univ. of Genoa (Italy)

    2009-06-15

    Purpose: to investigate dosimetric predictors of diarrhea during radiotherapy (RT) for prostate cancer. Patients and methods: all patients who underwent external-beam radiotherapy as part of treatment for localized prostate cancer at the University of Texas Medical Branch, Galveston, TX, USA, from May 2002 to November 2006 were extracted from the own database. From the cumulative dose-volume histogram (DVH), the absolute volumes (V-value) of intestinal cavity (IC) receiving 15, 30, and 45 Gy were extracted for each patient. Acute gastrointestinal toxicity was prospectively scored at each weekly treatment visit according to CTC (common toxicity criteria) v2.0. The endpoint was the development of peak grade {>=} 2 diarrhea during RT. Various patient, tumor, and treatment characteristics were evaluated using logistic regression. Results: 149 patients were included in the analysis, 112 (75.2%) treated with whole-pelvis intensity-modulated radiotherapy (WP-IMRT) and 37 (24.8%) with prostate-only RT, including or not including, the seminal vesicles (PORT {+-} SV). 45 patients (30.2%) developed peak grade {>=} 2 diarrhea during treatment. At univariate analysis, IC-V{sub 15} and IC-V{sub 30}, but not IC-V{sub 45}, were correlated to the endpoint; at multivariate analysis, only IC-V{sub 15} (p = 0.047) along with peak acute proctitis (p = 0.041) was independently correlated with the endpoint. Conclusion: these data provide a novel and prostate treatment-specific ''upper limit'' DVH for IC. (orig.)

  10. Dosimetric trade-offs in breast treatment with VMAT technique.

    Science.gov (United States)

    Fogliata, Antonella; Seppälä, Jan; Reggiori, Giacomo; Lobefalo, Francesca; Palumbo, Valentina; De Rose, Fiorenza; Franceschini, Davide; Scorsetti, Marta; Cozzi, Luca

    2017-02-01

    Breast planning with volumetric modulated arc therapy (VMAT) has been explored, especially for left-sided breast treatments, with the primary intent of lowering the heart dose and improving target dose homogeneity. As a trade-off, larger healthy tissue volumes would receive low dose levels, with the potential risk of increasing late toxicities and secondary cancer induction, although no clinical data are available today to confirm the risk level. The scope of this work is to explore the dosimetric trade-offs using two different VMAT plans. Two planning strategies for dual-partial-arc VMAT, RA_avoid and RA_full, with and without avoidance sectors, were explored in a cohort of 20 patients, for whole left breast irradiation for 40.05 Gy to the mean target dose in 15 fractions. Common dose objectives included a stringent dose homogeneity, mean dose to the heart <5 Gy, ipsilateral lung (Ilung) <8 Gy, contralateral lung (Clung) <2 Gy and contralateral breast (Cbreast) <3 Gy. RA_full showed a better dose conformity, lower high-dose spillage in the healthy tissue and lower skin dose. RA_avoid presented a reduction of the mean doses for all critical structures: 51% to the heart, 12% to the Ilung, 81% to the Clung and 73% to the Cbreast. All differences were significant with p < 0.0001. The adaptation of VMAT options to planning objectives reduced significantly the healthy tissue dose levels at the price of some high-dose spillage. Evaluation of the trade-offs for application to the different critical structures should drive in improving the usage of the VMAT technique for breast cancer treatment. Advances in knowledge: Different planning strategies in the same VMAT technique could give significant variations in dose distributions. The choice of the trade-offs would affect the possible future late toxicity and secondary cancer induction risk.

  11. Use of secondary phosphorescence for determination of the dose absorbed in dosimetric phosphors

    CERN Document Server

    Yaek, I V

    2002-01-01

    The measuring method of optically stimulated persistence (OSP) based on both the time division of the stimulating irradiation and luminescent response registration was applied for the radiation dosimetry. It was shown that the stimulation by the short-wave radiation crossing with spectrum of the dosimetric phosphor is possible. The spectrum of the stimulation of industry dosimetric phosphors was measured. The characteristics of the OSP registration for the phosphors which has manganese Mn sup 2 sup + as the activator is considered. Decay time of inner center luminescence is 40-50 ms. This method is used for the dosimetry of the natural quartzes to determine their age.

  12. Peer Assessment for Construction Management and Quantity Surveying Students

    Directory of Open Access Journals (Sweden)

    Patricia McLaughlin

    2012-11-01

    Full Text Available Students undertaking the Bachelor of ConstructionManagement degree course at RMIT University, Melbourne,qualify for registration with the Australian Institute ofQuantity Surveyors (AIQS and the Australian Institute ofBuilding (AIB upon graduation. Over the past decade thedegree course has been constantly upgraded and altered inline with recommendations from professional bodies such asthese and other industry partners. In 1994 the Departmentof Building and Construction Economics re-assesseda range of subjects including the first year technologysubjects. Out of the review a problem-based integratedlearning unit was developed and tested. This unit has nowbeen in place for ten years.Quantity surveying and construction management likemost other professions in the construction industryrequire teamwork and advanced consultation skills. Theseskills may be learnt through experience but there isconsiderable evidence that these skills can be taught in theundergraduate years. Therefore in line with team-basedapproaches used in industry and professional constructionsettings, this year a new assessment model - peerassessment - will be applied to the problem-based learningunit. This paper describes the procedures and processesused to introduce the change and examines the theoreticalbase upon which the model was developed.

  13. Category 3 threshold quantities for hazard categorization of nonreactor facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mandigo, R.L.

    1996-02-13

    This document provides the information necessary to determine Hazard Category 3 threshold quantities for those isotopes of interest not listed in WHC-CM-4-46, Section 4, Table 1.''Threshold Quantities.''

  14. 基于耕地压力指数和GM(1,1)模型的区域粮食安全状况研究——以甘肃省天水市为例%A Case Study of Tianshui City in Gansu: Plantation Preservation Quantity Research Based on Food Security and GM( 1,1 )Model

    Institute of Scientific and Technical Information of China (English)

    高小琛; 石培基; 潘竟虎; 吕立刚

    2011-01-01

    Taking Tianshui city in Cansu province for example, the aera of cultivated land and the plantation preservation quantity were determined based on Land - use changing data, population and food statistics between 1996 and 2005. The plantation preservation quantity of Tianshui the next 15 years was calculated in mathematical method of CM( 1,1)model. The results show that; the minimum area of cultivated land per capita and the plantation preservation quantity decreased between 1996 and 2005. Moreover, the plantation preservation quantity was alawys 1. The reason was that although per capita cultivated land continued to decline in Tianshui,the food production and per capita continued to increase because of increasing food productivity. The plantation preservation quantity will father reduce and the supply of land productivity was higher than the level of food consumption and regional food security risks was smalle in the next 15 years%在分析天水市1996-2005年耕地、人口、粮食动态变化的基础上,计算最小人均耕地面积和耕地压力指数,运用GM(1,1)模型对未来15 a天水市耕地压力指数进行了预测.研究结果显示:1996-2005年,虽然天水人均耕地面积持续减少,但由于耕地生产率不断提高,粮食产量和人均占有量在持续增加,最小人均耕地面积和耕地压力指数呈现降低的趋势,但是耕地压力指数始终在1之上.未来15 a耕地压力指数将进一步降低,耕地生产力的供给水平高于食物消费水平,区域粮食安全隐患较小.图5,表1,参10.

  15. Technical requirements for implementation of an individual monitoring service for evaluation of operational quantity HP(10) using thermoluminescent dosimetry; Requisitos tecnicos para a implantacao de um servico de monitoracao individual externa de corpo inteiro para fotons utilizando dosimetria termoluminescente

    Energy Technology Data Exchange (ETDEWEB)

    Francisco, Adelaide Benedita Armando

    2016-11-01

    This work aims to establish technical requirements for the development of a TLDs system for the assessment of operational quantity H{sub P}(10), in order to implement an external individual monitoring service in countries who do not have. This allows a better understanding of the technic and the thermoluminescent dosimetry system, thus contributing to identify the technical criteria to be followed by a dosimetry laboratory and evaluation of the dosimetric system performance. For this, the review of the specific literature of the dosimetry field was conducted and later the type and performance tests that must be followed by a dosimetric system were reproduced in practice. In additional was made a analysis of internationals standards norms and the technical regulation used in Brazil, to define the essentials type testes to a dosimetric system. To check the performance of a dosimetry system, a performance analysis of the Brazilian TLDs system was carried out over the past 6 years using the trumpet curve, where it was observed that most of TLDs system, in this review period, were approved and have excellent performance. The technical requirements for the development of a thermoluminescent dosimetry system ensure that the system provides technically reliable results and allow demonstration of compliance with the standard criteria established by national and international standards, and the implementation of the dosimetry system, is verified the compliance of the annual doses limits set for occupationally exposed. (author)

  16. Coordinated Lot-sizing and Dynamic Prizing under a Supplier All-units Quantity Discount

    Directory of Open Access Journals (Sweden)

    Sandra Transchel

    2008-05-01

    Full Text Available We consider an economic order quantity model where the supplier offers an all-units quantity discount and a price sensitive customer demand. We compare a decentralized decision framework where selling price and replenishment policy are determined independently to simultaneous decision making. Constant and dynamic pricing are distinguished. We derive structural properties and develop algorithms that determine the optimal pricing and replenishment policy and show how quantity discounts not only influence the purchasing strategy but also the pricing policy. A sensitivity analysis indicates the impact of the fixed-holding cost ratio, the discount policy, and the customers' price sensitivity on the optimal decisions.

  17. How to introduce physical quantities physically

    CERN Document Server

    Wagner, Serge A

    2015-01-01

    The centuries-long practice of the teaching turned mechanics into an academic construct detached from its underlying science, the physics of macroscopic bodies. In particular, the regularities that delineate the scope of validity of Newtonian mechanics was never used as premises in that construct. Instead, its logical structure has been built with the only purpose to ease the presentation of mechanics as an application of calculus and algebra. This leaves no room for the explicit physical description of the fundamental notions of the construct, such as the ability of (a system of) physical bodies to keep a spatial form, symbolized by a rigid measuring rod, and the possibility to count out even temporal intervals, symbolized by a standard clock, let alone the origin of the basic mechanical quantities. The comparison between (states of) physical objects is possible as far as the natural regularities enable a researcher to define an equivalence relation in a set of these objects. The class of macroscopic (or mac...

  18. Nurturing young writers: sustaining quality, not quantity.

    Science.gov (United States)

    Looi, L M

    2009-11-01

    The exponential growth in scientific journals and advent of the electronic era have led to such information overload that the sustainability of credible and quality publications is more urgent than ever. Editors and academics who commit themselves to nurturing young writers need to reaffirm their focus on quality rather than quantity of papers. Bearing in mind that publications should firstly be founded on good science, there are several approaches in helping the uninitiated develop and hone writing skills. Academic journals faithfully publish instructions to guide potential authors on the preparation and submission of manuscripts. For those with a gift for writing, this may suffice to start them soaring in their writing career. Others find the hands-on approach of writing workshops more effective in clarifying the rules of the writing game and dispelling the fear of writing. Workshops are good at demonstrating the basics, but the forging of a good writer is a long process in which a mentor can play an invaluable role. A nurturing mentor-mentee relationship should not be a stifling one, but one that leads, grows and finally liberates an independent writer. It is inevitable that the nature of scientific publications will change over time. Nonetheless, the sustainability of quality journals will remain linked to the continual generation of writers who uphold scientific truth and good writing values.

  19. 48 CFR 52.211-18 - Variation in Estimated Quantity.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Variation in Estimated....211-18 Variation in Estimated Quantity. As prescribed in 11.703(c), insert the following clause in... in the estimated quantity of unit-priced items: Variation in Estimated Quantity (APR 1984) If...

  20. 48 CFR 852.216-70 - Estimated quantities.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Estimated quantities. 852... Estimated quantities. As prescribed in 816.504(a), insert the following clause: Estimated Quantities (APR... percent of the estimated requirement or which provide that the Government shall guarantee any...

  1. Hwa measurement of turbulent diffusion of a scalar quantity

    OpenAIRE

    Antoš Pavel

    2012-01-01

    The paper deals with simultaneous measurement of the velocity and the scalar quantity by means of hot-wire anemometry. Statistical moments of the scalar quantity fluctuations can be obtained employing a dual hot-wire probe. An evaluation procedure of the quantity mean values and fluctuations is described. Results from the molar concentration measurement in binary-gas mixture are shown.

  2. Symmetries and Mei Conserved Quantities of Nonholonomic Controllable Mechanical Systems

    Institute of Scientific and Technical Information of China (English)

    XIA Li-Li; LI Yuan-Cheng; WANG Jing; HOU Qi-Bao

    2006-01-01

    This paper concentrates on studying the symmetries and a new type of conserved quantities called Mei conserved quantity. The criterions of the Mei symmetry, the Noether symmetry and the Lie symmetry are given. The conditions and the forms of the Mei conserved quantities deduced from these three symmetries are obtained. An example is given to illustrate the application of the result.

  3. Study on Model for High Yield and Good Quality of N, P Application Quantity and Density of Peppermint (Mentha piperita L.)%椒样薄荷氮、磷用量及密度高产优质回归模型研究

    Institute of Scientific and Technical Information of China (English)

    窦宏涛; 张连杰; 邢文艳; 王安

    2009-01-01

    为了探明在超高产条件下椒样薄荷高产优质的农艺模型以及对其精油品质的影响,采用三因子二次饱和D最优设计方案,选取对椒样薄荷精油产量影响较大的密度蜀、氮肥用量X2、磷肥用量X3为调控因子,以每公顷精油产量Y为目标函数,研究椒样薄荷栽培数学模型.结果表明,影响椒样薄荷精油产量的各因素权重依次为氮肥用量X2密度X1磷肥用量X3,依据建立的模型,目标精油产量≥100.5 kg/hm2时优质高产最佳农艺方案为:密度X117.55万~22.05万苗/hm2,氮肥用量X2纯氮172.5~217.5 kg/hm2,磷肥用量X3纯磷118.5~150 kg/hm2;品质分析结果表明,密度对精油品质有显著影响,氮肥用量对精油品质的影响与密度密切相关,在密度较低时影响不明显,而在密度较高时有一定的影响,适量控氮可以提高精油品质,过量施氮会降低精油品质,磷肥用量对精油品质影响不明显.%The study was carried out by using the principle of agricultural ecology and the qualified design of three square saturated D, in which the factors of density(X1), application quantity of nitrogen(X2) and phosphorus (X3) were taken as the adjusting factors, and the yield (Y) of each hectare as target function, Through the study we got a mathematic model for cultivation of peppermint. The result indicated that, under the condition of this experiment design, factors affecting yield of the essential oil of peppermint in experiment region were in order as application quantity of nitrogen(X2)> density(X1)> application quantity of phosphorus(X3) when the target yield was greater than 100.5 kg/hm2, the optimum formula of peppermint this region was as follows: density X1 was 175500~220500 plant/bm2, application amount of N fertilizerX2 was 172.5-217.5 kg/hm2, application amount of P2O5 fertilizer X3 was 118.5-150 kg/hm2; Quality analyses show: quality of the essential oil were influenced significantly by density, while the

  4. Radioecological and dosimetric consequences of the Chernobyl accident in France; Consequences radioecologiques et dosimetriques de l'accident de Tchernobyl en France

    Energy Technology Data Exchange (ETDEWEB)

    Renaud, Ph.; Beaugelin, K.; Maubert, H.; Ledenvic, Ph. [Inst. de Protection et de Surete Nucleaire, CEA Centre d' Etudes de Fontenay-aux-Roses, 92 (France)

    1997-11-01

    This study has as objective a survey of the radioecological and dosimetric consequences of the Chernobyl accident in France, as well as a prognosis for the years to come. It was requested by the Direction of Nuclear Installation Safety (DSIN) in relation to different organisms which effected measurements after this accident. It is based on the use of combined results of measurements and modelling by means of the code ASTRAL developed at IPSN. Various measurements obtained from five authorities and institutions, were made available, such as: activity of air and water, soil, processed food, agricultural and natural products. However, to achieve the survey still a modelling is needed. ASTRAL is a code for evaluating the ecological consequences of an accident. It allows establishing the correspondence between the soil Remnant Surface Activities (RSA, in Bq.m{sup -2}), the activity concentration of the agricultural production and the individual and collective doses resulting from external and internal exposures (due to inhalation and ingestion of contaminated nurture). The results of principal synthesis documents on the Chernobyl accident and its consequences were also used. The report is structured in nine sections, as follows: 1.Introduction; 2.Objective and methodology; 3.Characterization of radioactive depositions; 4;Remnant surface activities; 5.Contamination of agricultural products and foods; 6.Contamination of natural, semi-natural products and of drinking water; 7.Dosimetric evaluations; 8.Proposals for the environmental surveillance; 9.Conclusion. Finally, after ten years, one concludes that at presentthe dosimetric consequences of the Chernobyl accident in France were rather limited. For the period 1986-2046 the average individual effective dose estimated for the most struck zone is lower than 1500 {mu}Sv, which represents almost 1% of the average natural exposure for the same period. At present, the cesium 137 levels are at often inferior to those recorded

  5. Quebec's Child Care Services: What Are the Mechanisms Influencing Children's Behaviors across Quantity, Type, and Quality of Care Experienced?

    Science.gov (United States)

    Lemay, Lise; Bigras, Nathalie; Bouchard, Caroline

    2015-01-01

    The objective of this study was to examine how quantity, type, and quality of care interact in predicting externalizing and internalizing behaviors of 36-month-old children attending Quebec's educational child care from their first years of life. To do so, the authors examined two hypothesized models: (1) a mediation model where quantity, type,…

  6. Quebec's Child Care Services: What Are the Mechanisms Influencing Children's Behaviors across Quantity, Type, and Quality of Care Experienced?

    Science.gov (United States)

    Lemay, Lise; Bigras, Nathalie; Bouchard, Caroline

    2015-01-01

    The objective of this study was to examine how quantity, type, and quality of care interact in predicting externalizing and internalizing behaviors of 36-month-old children attending Quebec's educational child care from their first years of life. To do so, the authors examined two hypothesized models: (1) a mediation model where quantity, type,…

  7. Biokinetic and dosimetric studies of {sup 188}Re-hyaluronic acid: a new radiopharmaceutical for treatment of hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Melendez-Alafort, Laura [Dipartimento di Scienze Farmaceutiche, Universita degli Studi di Padova, 35131 Padua (Italy)], E-mail: laura.melendez@unipd.it; Nadali, Anna; Zangoni, Elena [Dipartimento di Scienze Farmaceutiche, Universita degli Studi di Padova, 35131 Padua (Italy); Banzato, Alessandra; Rondina, Maria [Dipartimento di Scienze Oncologiche e Chirurgiche, Universita degli Studi di Padova, Padua (Italy); Rosato, Antonio [Dipartimento di Scienze Oncologiche e Chirurgiche, Universita degli Studi di Padova, Padua (Italy); Istituto Oncologico Veneto, IOV, Padova, Padua (Italy); Mazzi, Ulderico [Dipartimento di Scienze Farmaceutiche, Universita degli Studi di Padova, 35131 Padua (Italy)

    2009-08-15

    Hepatocellular carcinoma (HCC) is the most common primary liver cancer and has very limited therapeutic options. Recently, it has been found that hyaluronic acid (HA) shows selective binding to CD44 receptors expressed in most cancer histotypes. Since the trend in cancer treatment is the use of targeted radionuclide therapy, the aim of this research was to label HA with rhenium-188 and to evaluate its potential use as a hepatocarcinoma therapeutic radiopharmaceutical. Methods: {sup 188}Re-HA was prepared by a direct labelling method to produce a ReO(O-COO){sub 2}-type coordination complex. {sup 188}Re-HA protein binding and its stability in saline, phosphate buffer, human serum and cysteine solutions were determined. Biokinetic and dosimetric data were estimated in healthy mice (n=60) using the Medical Internal Radiation Dose methodology and mouse model beta-absorbed fractions. To evaluate liver toxicity, alanine aminotranferase (AST) and aspartate aminotranferase (ALT) levels in mice were assessed and the liver maximum tolerated dose (MTD) of {sup 188}Re-HA was determined. Results: A stable complex of {sup 188}Re-HA was obtained with high radiochemical purity (>90%) and low serum protein binding (2%). Biokinetic studies showed a rapid blood clearance (T{sub 1/2}{alpha}=21 min). Four hours after administration, {sup 188}Re-HA was almost totally removed from the blood by the liver due to the selective uptake via HA-specific receptors (73.47{+-}5.11% of the injected dose). The liver MTD in mice was {approx}40 Gy after 7.4 MBq of {sup 188}Re-HA injection. Conclusions: {sup 188}Re-HA complex showed good stability, pharmacokinetic and dosimetric characteristics that confirm its potential as a new agent for HCC radiation therapy.

  8. Testing the Children Quantity-Quality Trade-Off in India

    OpenAIRE

    Kumar, Santosh; Kugler, Adriana

    2011-01-01

    Using data from a representative sample from India, we test the empirical validity of Quantity-Quality tarde-off model of Becker and Lewis (1973). To address the endogeneity arising from the joint determination of quantity and quality of children by parents, we instrument the family size by sex of the first child. We find a negative relationship between family size and children's educational attainment, even after controlling for parent's characteristics and birth order of children. ...

  9. Quantity discount contracts for supply chain coordination under asymmetric information and disruptions

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The quantity discount contracts are investigated for a one-supplier-one-retailer supply chain with asymmetric information when the retailer's cost is disrupted. While the retailer's cost structure is asymmetric information, two all-unit quantity discount contract models, fixed expected-profit percentage discount(FEPD) and fixed wholesale-pricing percentage discount(FWPD) under asymmetric information are proposed in a regular scenario. When the retailer's cost distribution fluctuates due to disruptions, the ...

  10. The Effect of Quantity, Quality and Timing of Headquarters-Initiated Knowledge Flows on Subsidiary Performance

    DEFF Research Database (Denmark)

    Tran, Yen; Mahnke, Volker; Ambos, Björn

    2010-01-01

    This paper develops and tests a model that explains how the quality, quantity and timing of knowledge flows from headquarters influence subsidiary performance. It extends recent research on vertical knowledge flows between global headquarters and international subsidiaries. We find a positive...... quality/performance relationship and a curvilinear quantity/performance relationship, indicating that too much knowledge sharing can be detrimental to the receiving subsidiary. Most importantly, we show that the timing of a knowledge flow significantly affects subsidiary sales performance....

  11. Theoretical and experimental determination of dosimetric characteristics for ADVANTAGE{sup TM} Pd-103 brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Meigooni, Ali S. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States)]. E-mail: alimeig@uky.edu; Dini, Sharifeh A. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States); Awan, Shahid B. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States); Dou, Kai [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States); Koona, Rafiq A. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States)

    2006-08-15

    ADVANTAGE{sup TM} Pd-103 brachytherapy source has been recently introduced by IsoAid{sup TM} for prostate permanent implants. Dosimetric characteristics (Dose rate constant, radial dose function, 2D-, and 1D-anisotropy functions) of this source model have been determined using both theoretical and experimental methods, following the updated TG-43U1 protocol. Derivation of the dose rate constant was based on recent NIST WAFAC calibration performed in accordance with the 1999 Standards. Measurements were performed in Solid Water{sup TM} using LiF TLD chips and the theoretical calculations were performed in Solid Water{sup TM} and liquid water phantom materials using PTRAN Monte Carlo code. The results of the Monte Carlo simulation have shown a dose rate constant of 0.69 cGy h{sup -1} U{sup -1} in liquid water and 0.67 cGy h{sup -1} U{sup -1} in Solid Water{sup TM} medium. The measured dose rate constant in Solid Water{sup TM} was found to be 0.68{+-}8% cGy h{sup -1} U{sup -1}, which is in a good agreement (within {+-}5%) to the Monte Carlo simulated data. The 2D- and 1D-anisotropy functions of the ADVANTAGE{sup TM} Pd-103 source were calculated for radial distances ranging from 0.5 to 5.0 cm. Radial dose function was determined for radial distances ranging from 0.2 to 8.0 cm using line source approximation. All these calculations are based on L {sub eff} equal to 3.61 cm, calculated following TG-43U1 recommendations. The tabulated data for 2D-anisotropy function, 1D-anisotropy function, dose rate constant and radial dose function have been produced for clinical application of this source model.

  12. Characteristics of the Receptor for the Biosphere Model

    Energy Technology Data Exchange (ETDEWEB)

    M.A. Wasiolek

    2005-04-05

    plan (BSC 2005 [DIRS 172782]). The scope of the revision was to develop dosimetric input parameters for the biosphere model that are consistent with the International Commission on Radiological Protection (ICRP) Publication 72 (ICRP 1996 [DIRS 152446]). The quantities developed previously (BSC 2004 [DIRS 169671]), which reflect the ICRP Publication 30 dosimetric methods (ICRP 30) (ICRP 1979 [DIRS 110386]; ICRP 1980 [DIRS 110351]; ICRP 1981 [DIRS 110352]) were not changed and were retained in this report.

  13. The effects of quantum gravity on some thermodynamical quantities

    Science.gov (United States)

    Kamali, A. D.; Shababi, H.; Nozari, K.

    2016-10-01

    In this paper, using a deformed algebra [X,P] = iℏ/(1 - α2P2) which is originated from various theories of gravity, we study thermodynamical properties of the classical and extreme relativistic gases in canonical ensembles. In this regards, we exactly calculate the modified partition function, Helmholtz free energy, internal energy, entropy, heat capacity and the thermal pressure which conclude to the familiar form of the equation of state for the ideal gas. The advantage of applying this algebra is not only considering all natural cutoffs but also its structure is similar to the other effective quantum gravity models such as polymer, Snyder and noncommutative space-time frameworks. Moreover, after obtaining some thermodynamical quantities including internal energy and entropy, we conclude at high temperature limits due to the decreasing of the number of microstates, these quantities reach to maximal bounds which do not exist in standard cases and it concludes that at the presence of gravity for both micro-canonic and canonic ensembles, the internal energy and the entropy tend to these upper bounds.

  14. The Model of Vender Selection and Order Quantity Allocation Based on Supply Chain Risk Management%基于供应链风险管理的供应商选择和订购量分配模型

    Institute of Scientific and Technical Information of China (English)

    刘鹿幸; 周永务

    2011-01-01

    Manufacturers in selecting vendors must measure all aspects of the performance of candidate vendors. From the view of supply chain risk, this paper constructed the fuzzy multi - objective programming model to select the supplier with the selection criteria such as cost, quality, on - time delivery and risk control. Through the use of chance - constrained programming and fuzzy set theory, the former model became the nonlinear programming model. Finally, the mathematical example was given to testify the effectiveness of the proposed model by using the mini - max method and Monte Carlo simulation method.%制造商时于供应商的选择必须综合考虑待选的供应商在各个方面的表现.以供应链风险为视角,考虑价格、质量、准时供货、风险控制为选择准则,建立供应商选择的模糊多目标规划模型.通过机会约束规划方法和模糊集理论,进一步转化成非线性规划模型.最后采用数学算例,使用极小极大法、蒙特卡罗仿真法验证该模型的有效性.

  15. Quantity of plant leaf area on three major public squares in Kunming City, China

    Institute of Scientific and Technical Information of China (English)

    DONGYan; ZHAOLin-sen; ZHAOYu-xiang

    2004-01-01

    Regressive formulae to calculate the quantity of plant leaf area for 13 species of ornamental plants were set up based on investigation data of 30 species on 3 major public squares (Dongfeng square, Shengli square and Guandu square) in Kunruing City, China, which were applied to calculate quantities of plant leaf area of these 13 species. The quantities of plant leaf area for the other 17 ornamental plant species on these squares were directly measured, and the total quantity of plant leaf area of each studied square was obtained individually. The results showed that the quantity of plant leaf area on Shengli square with ornamental plants structure composed of arbor tree species, shrub tree species and turf grass was highest among the three squares. It is believed that the design model of multi-storied vertical structure and proper tending of plant community could not only increase the quantity of plant leaf area, but also play an important role in generating ecological and landscaping benefits.Some corresponding suggestions were put forward on the basis of comprehensive analyses on the plant leaf area quantity of the three representative squares in Kunming urban area.

  16. 考虑产能限制及缺货惩罚的MTO投产计划决策%Decision-making Model of Planning Quantity Put into Production for the Make-To-Order Enterprises with Limited Capacity and Shortage Penalty Cost

    Institute of Scientific and Technical Information of China (English)

    高华丽; 但斌; 张旭梅

    2013-01-01

    较低的生产重复性使MTO企业的生产系统具有较大随机性,导致其产品投产量计划制定面临易过量或不足的风险.针对这一问题,考虑MTO企业的生产能力限制及其产品合格率的随机性,综合权衡初始投产过量、初始投产不足需补产及缺货等因素导致的总成本损失,以成本损失最小化为目标,建立了产品投产量计划决策模型来解决最优产品投产量计划的获得问题,并进行了相应的理论分析和数值仿真.研究表明:模型可有效求解出最优的产品计划投产量;考虑产能限制和缺货损失可降低企业的综合成本损失;企业产能对综合成本损失的影响同单位缺货成本与欠产再投产的单位产品成本之比有关;提高合格品率中值对降低综合成本损失至关重要.%Because of the low production repeatability and the uncertainty of the products eligibility-rate of the manufacturing enterprises with Make-To-Order mode to some extent,the decision-making of planning quantity put into production for the MTO enterprises becomes more difficult.In order to solve this problem,the paper proposed a decision-making model of planning quantity put into production for the limited capacity MTO enterprises,which aimed at minimize the expected loss of integrated cost,and presented the method to obtain the optimal planning quantity put into production and carried out theoretical analysis and sensitivity analysis of the key parameters.It is shown that the model is effective,the influence of the production capacity on the expected loss of integrated cost lies on the ratio of the excess cost to the shortage cost and improving the median rate of the products eligibility-rate is essential to reducing quantity of planning put-into-production.

  17. Relative quantity judgments in the beluga whale (Delphinapterus leucas) and the bottlenose dolphin (Tursiops truncatus).

    Science.gov (United States)

    Abramson, José Z; Hernández-Lloreda, Victoria; Call, Josep; Colmenares, Fernando

    2013-06-01

    Numerous studies have documented the ability of many species to make relative quantity judgments using an analogue magnitude system. We investigated whether one beluga whale, Delphinapterus leucas, and three bottlenose dolphins, Tursiops truncatus, were capable of selecting the larger of two sets of quantities, and analyzed if their performance matched predictions from the object file model versus the analog accumulator model. In Experiment 1, the two sets were presented simultaneously, under water, and they were visually (condition 1) or echoically (condition 2) available at the time of choice. In experiment 2, the two sets were presented above the water, successively (condition 1) or sequentially, item-by-item (condition 2), so that they were not visually available at the time of choice (condition 1) or at any time throughout the experiment (condition 2). We analyzed the effect of the ratio between quantities, the difference between quantities, and the total number of items presented on the subjects' choices. All subjects selected the larger of the two sets of quantities above chance levels in all conditions. However, unlike most previous studies, the subjects' choices did not match the predictions from the accumulator model. Whether these findings reflect interspecies differences in the mechanisms which underpin relative quantity judgments remains to be determined.

  18. Thermodynamics of quantum systems with multiple conserved quantities

    Science.gov (United States)

    Guryanova, Yelena; Popescu, Sandu; Short, Anthony J.; Silva, Ralph; Skrzypczyk, Paul

    2016-07-01

    Recently, there has been much progress in understanding the thermodynamics of quantum systems, even for small individual systems. Most of this work has focused on the standard case where energy is the only conserved quantity. Here we consider a generalization of this work to deal with multiple conserved quantities. Each conserved quantity, which, importantly, need not commute with the rest, can be extracted and stored in its own battery. Unlike the standard case, in which the amount of extractable energy is constrained, here there is no limit on how much of any individual conserved quantity can be extracted. However, other conserved quantities must be supplied, and the second law constrains the combination of extractable quantities and the trade-offs between them. We present explicit protocols that allow us to perform arbitrarily good trade-offs and extract arbitrarily good combinations of conserved quantities from individual quantum systems.

  19. Law of genome evolution direction: Coding information quantity grows

    Institute of Scientific and Technical Information of China (English)

    Liao-fu LUO

    2009-01-01

    The problem of the directionality of genome evolution is studied. Based on the analysis of C-value paradox and the evolution of genome size, we propose that the function-coding information quantity of a genome always grows in the course of evolution through sequence duplication, expansion of code,and gene transfer from outside. The function-coding information quantity of a genome consists of two parts, p-coding information quantity that encodes functional protein and n-coding information quantity that encodes other functional elements. The evidences on the law of the evolutionary directionality are indicated. The needs of function are the motive force for the expansion of coding information quantity,and the information quantity expansion is the way to make functional innovation and extension for a species. Therefore, the increase of coding information quantity of a genome is a measure of the acquired new function, and it determines the directionality of genome evolution.

  20. Intraoperative radiotherapy in the theatre room with electron beams: technical and dosimetric description of Sordina LIAC accelerator; Radioterapia intraoperatoria en quirofano con haces de electrones: descripcion tecnica y dosimetrica del acelerador dedicado Sordina LIAC

    Energy Technology Data Exchange (ETDEWEB)

    Sendon del Rio, J. R.; Ayala Lazaro, R.; Gomez Cores, S.; Garcia Hernandez, M. J.; Polo Cezon, R.; Jimenez Rojas, R.; Lopez Bote, M. A.

    2015-05-01

    n this work we show our experience during the commissioning of a mobile electron-beam accelerator dedicated to intraoperative radiation therapy in the theatre room. The linac is a Sordina LIAC 12 MeV model with a hard-docking applicator system. We describe the linac, the measurement methods and the specific dosimetry. The dosimetric behavior is also discussed. Differences with other applicator systems can be explained from the particular head design of the linac. (Author)

  1. Dosimetric impact of orthopedic metal artifact reduction (O-MAR) on Spine SBRT patients.

    Science.gov (United States)

    Shen, Zhilei Liu; Xia, Ping; Klahr, Paul; Djemil, Toufik

    2015-09-08

    The dosimetric impact of orthopedic metal artifact reduction (O-MAR) on spine SBRT patients has not been comprehensively studied, particularly with spinal prostheses in high-dose gradient regions. Using both phantom and patient datasets, we investigated dosimetric effects of O-MAR in combination of various metal locations and dose calculation algorithms. A physical phantom, with and without a titanium insert, was scanned. A clinical patient plan was applied to the artifact-free reference, non-O-MAR, and O-MAR phantom images with the titanium located either inside or outside of the tumor. Subsequently, five clinical patient plans were calculated with pencil beam and Monte Carlo (iPlan) on non-O-MAR and O-MAR patient images using an extended CT-density table. The dose differences for phantom plans and patient plans were analyzed using dose distributions, dose-volume histograms (DVHs), gamma index, and selected dosimetric endpoints. From both phantom plans and patient plans, O-MAR did not affect dose distributions and DVHs while minimizing metal artifacts. Among patient plans, we found that, when the same dose calculation method was used, the difference in the dosimetric endpoints between non-O-MAR and O-MAR datasets were small. In conclusion, for spine SBRT patients with spinal prostheses, O-MAR image reconstruction does not affect dose calculation accuracy while minimizing metal artifacts. Therefore, O-MAR images can be safely used for clinical spine SBRT treatment planning.

  2. Reserves in Economic Quantities of Military Logistics and Inventory Model Study%军事物流储备中经济批量库存模型的研究

    Institute of Scientific and Technical Information of China (English)

    史玉敏

    2012-01-01

    In military logistics, the economic lot size model of reserves is an important model, so how to rationally and economically solve the storage problems is the biggest aviation materials management. The cost of storage is a major part of aviation materials business expenses and occupies a very large part of aviation materials prevention.%在军事物流储备中经济批量模型是一种重要的模型,如何最合理、最经济地解决好存储问题是航材管理中的大问题.存储的费用是航材业务经费的主要部分,在航材保障中占据非常大的部分.

  3. Dosimetric impact of density variations in Solid Water 457 water-equivalent slabs.

    Science.gov (United States)

    Litzenberg, Dale W; Amro, Hanan; Prisciandaro, Joann I; Acosta, Eduardo; Gallagher, Ian; Roberts, Don A

    2011-04-22

    The purpose of this study was to determine the dosimetric impact of density variations observed in water-equivalent solid slabs. Measurements were performed using two 30 cm × 30 cm water-equivalent slabs, one being 4 cm think and the other 5 cm thick. The location and extent of density variations were determined by computed tomography (CT) scans. Additional imaging measurements were made with an amorphous silicon megavoltage portal imaging device and an ultrasound unit. Dosimetric measurements were conducted with a 2D ion chamber array, and a scanned diode in water. Additional measurements and calculations were made of small rectilinear void inhomogeneities formed with water-equivalent slabs, using a 2D ion chamber array and the convolution superposition algorithm. Two general types of density variation features were observed on CT images: 1) regions of many centimeters across, but typically only a few millimeters thick, with electron densities a few percent lower than the bulk material, and 2) cylindrical regions roughly 0.2 cm in diameter and up to 20 cm long with electron densities up to 5% lower than the surrounding material. The density variations were not visible on kilovoltage, megavoltage or ultrasound images. The dosimetric impact of the density variations were not detectable to within 0.1% using the 2D ion chamber array or the scanning photon diode at distances 0.4 cm to 2 cm beyond the features. High-resolution dosimetric calculations using the convolution-superposition algorithm with density corrections enabled on CT-based datasets showed no discernable dosimetric impact. Calculations and measurements on simulated voids place the upper limit on possible dosimetric variations from observed density variations at much less than 0.6%. CT imaging of water-equivalent slabs may reveal density variations which are otherwise unobserved with kV, MV, or ultrasound imaging. No dosimetric impact from these features was measureable with an ion chamber array or

  4. Biologically Weighted Quantities in Radiotherapy: an EMRP Joint Research Project

    Directory of Open Access Journals (Sweden)

    Rabus Hans

    2014-01-01

    Full Text Available Funded within the European Metrology Research Programme (EMRP [1], the joint research project “Biologically weighted quantities in radiotherapy” (BioQuaRT [2] aims to develop measurement and simulation techniques for determining the physical properties of ionising particle tracks on different length scales (about 2 nm to 10 μm, and to investigate the correlation of these track structure characteristics with the biological effects of radiation at the cellular level. Work package 1 develops micro-calorimeter prototypes for the direct measurement of lineal energy and will characterise their response for different ion beams by experiment and modelling. Work package 2 develops techniques to measure particle track structure on different length scales in the nanometre range as well as a measurement device integrating a silicon microdosimeter and a nanodosimeter. Work package 3 investigates the indirect effects of radiation based on probes for quantifying particular radical and reactive oxygen species (ROS. Work package 4 focuses on the biological aspects of radiation damage and will produce data on initial DNA damage and late effects for radiotherapy beams of different qualities. Work package 5 provides evaluated data sets of DNA cross-sections and develops a multi-scale model to address microscopic and nanometric track structure properties. The project consortium includes three linked researchers holding so-called Researcher Excellence Grants, who carry out ancillary investigations such as developing and benchmarking a new biophysical model for induction of early radiation damage and developing methods for the translation of quantities derived from particle track structure to clinical applications in ion beam therapy.

  5. SU-E-T-332: Dosimetric Impact of Photon Energy and Treatment Technique When Knowledge Based Auto-Planning Is Implemented in Radiotherapy of Localized Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z; Kennedy, A [Sarah Cannon, Nashville, TN (United States); Larsen, E; Grow, A; Hayes, C; Balamucki, C [North Florida Cancer Center, Gainesville, FL (United States); Salmon, H; Thompson, M [Lake City Cancer Center, Lake City, FL (United States)

    2015-06-15

    Purpose: The aim of this study was to investigate the dosimetric impact of the combination of photon energy and treatment technique on radiotherapy of localized prostate cancer when knowledge based planning was used. Methods: A total of 16 patients with localized prostate cancer were retrospectively retrieved from database and used for this study. For each patient, four types of treatment plans with different combinations of photon energy (6X and 10X) and treatment techniques (7-field IMRT and 2-arc VMAT) were created using a prostate DVH estimation model in RapidPlan™ and Eclipse treatment planning system (Varian Medical System). For any beam arrangement, DVH objectives and weighting priorities were generated based on the geometric relationship between the OAR and PTV. Photon optimization algorithm was used for plan optimization and AAA algorithm was used for final dose calculation. Plans were evaluated in terms of the pre-defined dosimetric endpoints for PTV, rectum, bladder, penile bulb, and femur heads. A Student’s paired t-test was used for statistical analysis and p > 0.05 was considered statistically significant. Results: For PTV, V95 was statistically similar among all four types of plans, though the mean dose of 10X plans was higher than that of 6X plans. VMAT plans showed higher heterogeneity index than IMRT plans. No statistically significant difference in dosimetry metrics was observed for rectum, bladder, and penile bulb among plan types. For left and right femur, VMAT plans had a higher mean dose than IMRT plans regardless of photon energy, whereas the maximum dose was similar. Conclusion: Overall, the dosimetric endpoints were similar regardless of photon energy and treatment techniques when knowledge based auto planning was used. Given the similarity in dosimetry metrics of rectum, bladder, and penile bulb, the genitourinary and gastrointestinal toxicities should be comparable among the selections of photon energy and treatment techniques.

  6. Dosimetric verification in water of a Monte Carlo treatment planning tool for proton, helium, carbon and oxygen ion beams at the Heidelberg Ion Beam Therapy Center.

    Science.gov (United States)

    Tessonnier, T; Böhlen, T T; Ceruti, F; Ferrari, A; Sala, P; Brons, S; Haberer, T; Debus, J; Parodi, K; Mairani, A

    2017-07-31

    The introduction of 'new' ion species in particle therapy needs to be supported by a thorough assessment of their dosimetric properties and by treatment planning comparisons with clinically used proton and carbon ion beams. In addition to the latter two ions, helium and oxygen ion beams are foreseen at the Heidelberg Ion Beam Therapy Center (HIT) as potential assets for improving clinical outcomes in the near future. We present in this study a dosimetric validation of a FLUKA-based Monte Carlo treatment planning tool (MCTP) for protons, helium, carbon and oxygen ions for spread-out Bragg peaks in water. The comparisons between the ions show the dosimetric advantages of helium and heavier ion beams in terms of their distal and lateral fall-offs with respect to protons, reducing the lateral size of the region receiving 50% of the planned dose up to 12 mm. However, carbon and oxygen ions showed significant doses beyond the target due to the higher fragmentation tail compared to lighter ions (p and He), up to 25%. The Monte Carlo predictions were found to be in excellent geometrical agreement with the measurements, with deviations below 1 mm for all parameters investigated such as target and lateral size as well as distal fall-offs. Measured and simulated absolute dose values agreed within about 2.5% on the overall dose distributions. The MCTP tool, which supports the usage of multiple state-of-the-art relative biological effectiveness models, will provide a solid engine for treatment planning comparisons at HIT.

  7. Dosimetric verification in water of a Monte Carlo treatment planning tool for proton, helium, carbon and oxygen ion beams at the Heidelberg Ion Beam Therapy Center

    Science.gov (United States)

    Tessonnier, T.; Böhlen, T. T.; Ceruti, F.; Ferrari, A.; Sala, P.; Brons, S.; Haberer, T.; Debus, J.; Parodi, K.; Mairani, A.

    2017-08-01

    The introduction of ‘new’ ion species in particle therapy needs to be supported by a thorough assessment of their dosimetric properties and by treatment planning comparisons with clinically used proton and carbon ion beams. In addition to the latter two ions, helium and oxygen ion beams are foreseen at the Heidelberg Ion Beam Therapy Center (HIT) as potential assets for improving clinical outcomes in the near future. We present in this study a dosimetric validation of a FLUKA-based Monte Carlo treatment planning tool (MCTP) for protons, helium, carbon and oxygen ions for spread-out Bragg peaks in water. The comparisons between the ions show the dosimetric advantages of helium and heavier ion beams in terms of their distal and lateral fall-offs with respect to protons, reducing the lateral size of the region receiving 50% of the planned dose up to 12 mm. However, carbon and oxygen ions showed significant doses beyond the target due to the higher fragmentation tail compared to lighter ions (p and He), up to 25%. The Monte Carlo predictions were found to be in excellent geometrical agreement with the measurements, with deviations below 1 mm for all parameters investigated such as target and lateral size as well as distal fall-offs. Measured and simulated absolute dose values agreed within about 2.5% on the overall dose distributions. The MCTP tool, which supports the usage of multiple state-of-the-art relative biological effectiveness models, will provide a solid engine for treatment planning comparisons at HIT.

  8. Dosimetric behavior of thermoluminescent dosimeters at low doses in diagnostic radiology; Comportamiento dosimetrico de dosimetros termoluminiscentes a bajas dosis en radiodiagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Del Sol F, S.; Garcia S, R.; Guzman M, J.; Sanchez G, D.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Ramirez R, G. [Hospital Juarez de Mexico, Av. IPN 5160, Col. Magdalena de las Salinas, 07760 Mexico D. F. (Mexico); Gaona, E., E-mail: susi2489@hotmail.com [Universidad Autonoma Metropolitana, Unidad Xochimilco, Calz. del Hueso 1100, Col. Villa Quietud, 04960 Mexico D. F. (Mexico)

    2015-10-15

    Thermoluminescent (Tl) characteristics of TLD-100, LiF:Mg,Cu,P, and CaSO{sub 4}: Dy the under homogeneous field of X-ray beams of diagnostic irradiation and its verification using thermoluminescent dosimetry is presented. The irradiations were performed utilizing an X-ray beam generated by a Radiology Mexican Company: MRH-II E GMX 325-AF SBV-1 model, with Rotating Anode X-Ray Tube installed in the Hospital Juarez Norte de Mexico in Mexico City. Different thermoluminescent characteristics of dosimetric material were studied, such as, batch homogeneity, Tl glow curve, Tl response as a function of X-ray dose, reproducibility and fading. Materials were calibrated in terms of absorbed dose to the standard calibration distance and positioned in a generic Phantom was used. Dose verification and comparison with the measurements made with that obtained by TLD-100 were analyzed. Preliminary results indicate the dosimetric peak appears at 243, 236 and 277 ± 5 degrees C respectively, these peaks are in agreement with that reported in the literature. Tl glow curve as a function of X-ray dose showed a linearity in the range from 1.76 mGy up to 14.70 mGy for all materials. Fading for a period of one month at room temperature showed low fading LiF:Mg,Cu,P, medium and high for TLD-100 and CaSO{sub 4}: Dy. The results suggest that the three materials are suitable for measurements at low doses in radiodiagnostic, however, for its dosimetric characteristics are most effective for individual applications: personal dosimetry and monitors limb (LiF:Mg,Cu,P), clinical dosimetry and environmental (TLD-100 and CaSO{sub 4}: Dy). (Author)

  9. BQ计价模式下工程项目投标报价博弈模型研究%Study of Game-Based Bidding Quotation Model under the Bill of Quantities

    Institute of Scientific and Technical Information of China (English)

    陈起俊; 梁宝栋

    2012-01-01

    In improving the accuracy of the analysis of competitors' bidding strategies to improve the successful rate. Project game-based bidding quotation models face with some constraints due to the limitations of assumptions about the rationality and the risk attitudes of the bidders. Because of such considerations, this study relaxes the basic assumption of "risk-neutral" ton the background of the implementation of the new list price model,introduces the bidder's risk attitude factors,establishes the game-based bidding quotation model of the comprehensive evaluation method,and simulates with some real data looking forward to the scientific guidance to the bidders.%工程项目投标报价博弈模型一方面能够提高对竞争对手报价策略分析的准确度和投标中标率,另一方面由于对投标人理性程度、风险态度等假设的局限性,其在投标报价实际应用中也面临着一些约束.基于这种考虑,以清单计价模式的实施为背景,将放松风险中性这一基本假设引入工程项目投标人的风险态度因子,在综合评估法基础上,构建BQ计价模式下的投标报价博弈模型,并通过案例进行模拟分析,以期能科学地指导投标报价.

  10. Quantity Study and Numerical Simulation on Thermo-Coupled Mathematic Model%热采耦合数学模型定量化研究及数值模拟

    Institute of Scientific and Technical Information of China (English)

    杨文哲; 宋永臣; 王志国; 刘瑜; 赵越超; 朱宁军

    2012-01-01

    针对稠油油藏开发过程的薄弱环节,提出了油藏热质传递过程的黑箱分析法和白箱分析法,建立了包含蒸汽相的稠油热采耦合黑箱模型和白箱模型,使得储层温度场模型得以完整化和系统化。应用CMG软件进行数值模拟,验证了所建数学模型的合理性,并得到了孔隙度对油藏温度的影响关系。最后,对油藏热流体的指进现象进行了机理分析,并总结了热流体指进现象的产生范围。%Focusing on the weak part of heavy oil recovery, Black box and White box analysis are proposed in the heat and mass transfer process in oil reservoir, then Black box and White box models are developed containing steam phase, which complete and systematize reservoir temperature models. Numerical simulation is carried out by CMG software, from which verified the reasonable of models above and obtained the porosity effect on reservoir temperature. Fingering flow mechanism of heat fluid in reservoir is analysed, and the temperature ranges for engendering this fingering phenomenon are summarized.

  11. Market making, prices, and quantity limits

    NARCIS (Netherlands)

    Dupont, Dominique

    2000-01-01

    This article develops a model of spread and depth setting under asymmetric information where the equilibrium depth is proportionally more sensitive than the spread to changes in the degree of information asymmetry. The analysis uses a one-period model in which a risk-neutral, monopolistic market mak

  12. UnLoadC3: Ensembles of climate change projections for two river catchment areas in Austria - Contributions to an overall uncertainty assessment framework for the modelling of water quantity and nutrient transport

    Science.gov (United States)

    Matulla, Christoph; Hollosi, Brigitta; Schulz, Karsten; Schürz, Christoph; Mehdi, Bano; Ertl, Thomas; Pressl, Alexander

    2017-04-01

    The objective of UnLoadC3 is to examine the impacts of uncertainty - inherent in data and modelling - on projections of water flow and nutrient transport within two selected river catchment areas (Schwechat and Raab in Austria) under climate change conditions. To access future climate change, ensembles of climate projections from the EURO-CORDEX initiative - given on grids with a 12 km spacing - have been used. These ensembles have been driven by two RCPs (RCP4.5 and RCP8.5) used within the Fifth Assessment Report of the IPCC. In order to provide climate change projections on the required impact scales, statistical downscaling techniques as well as bias correction methods have been applied. Climate variables, such as minimum, maximum, mean temperature and precipitation totals given on a daily base were analyzed. This local scale daily information is entered into the water quality model SWAT, which simulates water balance, pertaining sediment- and nutrient-transport processes across the two considered river watersheds.

  13. Thermohaline instability and rotation-induced mixing. III - Grid of stellar models and asymptotic asteroseismic quantities from the pre-main sequence up to the AGB for low- and intermediate-mass stars at various metallicities

    CERN Document Server

    Lagarde, N; Charbonnel, C; Eggenberger, P; Ekström, S; Palacios, A

    2012-01-01

    The availability of asteroseismic constraints for a large sample of stars from the missions CoRoT and Kepler paves the way for various statistical studies of the seismic properties of stellar populations. In this paper, we evaluate the impact of rotation-induced mixing and thermohaline instability on the global asteroseismic parameters at different stages of the stellar evolution from the Zero Age Main Sequence to the Thermally Pulsating Asymptotic Giant Branch to distinguish stellar populations. We present a grid of stellar evolutionary models for four metallicities (Z = 0.0001, 0.002, 0.004, and 0.014) in the mass range between 0.85 to 6.0 Msun. The models are computed either with standard prescriptions or including both thermohaline convection and rotation-induced mixing. For the whole grid we provide the usual stellar parameters (luminosity, effective temperature, lifetimes, ...), together with the global seismic parameters, i.e. the large frequency separation and asymptotic relations, the frequency corre...

  14. Design and dosimetric characteristics of a new endocavitary contact radiotherapy system using an electronic brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Susan; Garcia-Ramirez, Jose; Lu Wei; Myerson, Robert J.; Parikh, Parag [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201 (United States); Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States)

    2012-11-15

    Purpose: To present design aspects and acceptance tests performed for clinical implementation of electronic brachytherapy treatment of early stage rectal adenocarcinoma. A dosimetric comparison is made between the historically used Philips RT-50 unit and the newly developed Axxent{sup Registered-Sign} Model S700 electronic brachytherapy source manufactured by Xoft (iCad, Inc.). Methods: Two proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Two custom surface applicators were manufactured by Xoft and were designed to fit and interlock with the proctoscope cones from ESI. Dose rates, half value layers (HVL), and percentage depth dose (PDD) measurements were made with the Xoft system and compared to historical RT-50 data. A description of the patient treatment approach and exposure rates during the procedure is also provided. Results: The electronic brachytherapy system has a lower surface dose rate than the RT-50. The dose rate to water on the surface from the Xoft system is approximately 2.1 Gy/min while the RT-50 is 10-12 Gy/min. However, treatment times with Xoft are still reasonable. The HVLs and PDDs between the two systems were comparable resulting in similar doses to the target and to regions beyond the target. The exposure rate levels around a patient treatment were acceptable. The standard uncertainty in the dose rate to water on the surface is approximately {+-}5.2%. Conclusions: The Philips RT-50 unit is an out-of-date radiotherapy machine that is no longer manufactured with limited replacement parts. The use of a custom-designed proctoscope and Xoft surface applicators allows delivery of a well-established treatment with the ease of a modern radiotherapy device. While the dose rate is lower with the use of Xoft, the treatment times are still reasonable. Additionally, personnel may stand farther away from the Xoft radiation source, thus potentially reducing radiation exposure to the operator and other personnel.

  15. Strategies for reducing intra-fraction motion induced dosimetric effects in proton therapy

    Science.gov (United States)

    Zhao, Li

    Intra-fraction respiration motion during radiation delivery presents a major challenge to radiation therapy. There has been a growing effort to characterize and manage internal organ motion in radiation therapy, however very few studies focus on tackling this issue in proton therapy. Current practice for treating lung tumors in proton therapy is still to apply population-based margins to account for internal tumor motion, which can lead to target underdosage and normal tissue overdosage. This thesis explores the intra-fraction motion induced dosimetric effects from both computational treatment planning and experimental studies. Four-dimensional CT scans are used to analyze the patient-specific tumor motion characteristics. A feasible method to design the range compensator by using the maximum intensity projection (MIP) images is proposed. Results demonstrate that this MIP approach ensures adequate tumor coverage throughout the entire respiratory cycle whilst maintaining normal tissue dose under clinical constraints. Based on 4D-CT scans, dose convolution is used for assessing the accuracy of Gaussian probability density function for modeling the patient-specific respiratory motion on dose distribution. Non-negligible dose discrepancy is observed in comparisons of convolved dose distributions, and patient-specific respiration PDF is advocated. In addition, an experimental phantom study primarily focusing on the interplay effect between target motion and the scanning beam motion is implemented in two proton beam delivery systems: double scattering and uniform scanning. Measurement results suggest that dose blurring effect is dominant, and interplay effect is trivial in the uniform scanning system due to dose repainting.

  16. SU-E-T-652: Quantification of Dosimetric Uncertainty of I-125 COMS Eye Plaque

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, C; Ahmad, S; Firestone, B; Johnson, D; Matthiesen, C; De La Fuente Herman, T [University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: To compare dosimetrically three plan calculation systems (Plato, Varian Brachytherapy, and in-house-made Excel) available for I-125 COMS eye plaque treatment with measurement. Methods: All systems assume homogeneous media and calculations are based on a three-dimensional Cartesian coordinates, Plato and Brachytherapy Planning are based on AAPM TG-43 and the in-house Excel program only on inverse square corrections. Doses at specific depths were measured with EBT3 Gafchromic film from a fully loaded and a partially loaded 16 mm plaque (13 and 8 seeds respectively, I-125, model 6711 GE, Oncura). Measurements took place in a water tank, utilizing solid water blocks and a 3D-printed plaque holder. Taking advantage that gafchromic film has low energy dependence, a dose step wedge was delivered with 6 MV photon beam from a Varian 2100 EX linac for calibration. The gray-scale to dose in cGy was obtained with an Epson Expression 10000 XL scanner in the green channel. Treatment plans were generated for doses of 2200 cGy to a depth of 7 mm, and measurements were taken on a sagittal plane. Results: The calculated dose at the prescription point was 2242, 2344, and 2211 cGy with Excel, Brachyvision and Plato respectively for a fully loaded plaque, for the partially loaded plaque the doses were 2266, 2477, and 2193 cGy respectively. At 5 mm depth the doses for Brachyvision and Plato were comparable (3399 and 3267 cGy respectively), however, the measured dose in film was 3180 cGy which was lower by as much as 6.4% in the fully loaded plaque and 7.6% in the partially loaded plaque. Conclusion: Careful methodology and calibration are essential when measuring doses at specific depth due to the sensitivity and rapid dose fall off of I-125.

  17. Property of Fluctuations of Sales Quantities by Product Category in Convenience Stores.

    Directory of Open Access Journals (Sweden)

    Gaku Fukunaga

    Full Text Available The ability to ascertain the extent of product sale fluctuations for each store and locality is indispensable to inventory management. This study analyzed POS data from 158 convenience stores in Kawasaki City, Kanagawa Prefecture, Japan and found a power scaling law between the mean and standard deviation of product sales quantities for several product categories. For the statistical domains of low sales quantities, the power index was 1/2; for large sales quantities, the power index was 1, so called Taylor's law holds. The value of sales quantities with changing power indixes differed according to product category. We derived a Poissonian compound distribution model taking into account fluctuations in customer numbers to show that the scaling law could be explained theoretically for most of items. We also examined why the scaling law did not hold in some exceptional cases.

  18. Torsor Theory of Physical Quantities and their Measurement

    Directory of Open Access Journals (Sweden)

    Domotor Zoltan

    2017-08-01

    Full Text Available The principal objective of this paper is to provide a torsor theory of physical quantities and basic operations thereon. Torsors are introduced in a bottom-up fashion as actions of scale transformation groups on spaces of unitized quantities. In contrast, the shortcomings of other accounts of quantities that proceed in a top-down axiomatic manner are also discussed. In this paper, quantities are presented as dual counterparts of physical states. States serve as truth-makers of metrological statements about quantity values and are crucial in specifying alternative measurement units for base quantities. For illustration and ease of presentation, the classical notions of length, time, and instantaneous velocity are used as primordial examples. It is shown how torsors provide an effective description of the structure of quantities, systems of quantities, and transformations between them. Using the torsor framework, time-dependent quantities and their unitized derivatives are also investigated. Lastly, the torsor apparatus is applied to deterministic measurement of quantities.

  19. Relative quantity judgments in South American sea lions (Otaria flavescens).

    Science.gov (United States)

    Abramson, José Z; Hernández-Lloreda, Victoria; Call, Josep; Colmenares, Fernando

    2011-09-01

    There is accumulating evidence that a variety of species possess quantitative abilities although their cognitive substrate is still unclear. This study is the first to investigate whether sea lions (Otaria flavescens), in the absence of training, are able to assess and select the larger of two sets of quantities. In Experiment 1, the two sets of quantities were presented simultaneously as whole sets, that is, the subjects could compare them directly. In Experiment 2, the two sets of quantities were presented item-by-item, and the totality of items was never visually available at the time of choice. For each type of presentation, we analysed the effect of the ratio between quantities, the difference between quantities and the total number of items presented. The results showed that (1) sea lions can make relative quantity judgments successfully and (2) there is a predominant influence of the ratio between quantities on the subjects' performance. The latter supports the idea that an analogue representational mechanism is responsible for sea lions' relative quantities judgments. These findings are consistent with previous reports of relative quantities judgments in other species such as monkeys and apes and suggest that sea lions might share a similar mechanism to compare and represent quantities.

  20. Application on Self-Exciting Threshold Auto-Regressive Model to forecast quantity of water irrigational requirement for rice%门限自回归模型在水稻需水量预测中的应用

    Institute of Scientific and Technical Information of China (English)

    张焕昭; 韩军利; 唐依伟; 付强

    2003-01-01

    通过对三江平原井灌水稻各生育阶段需水量的长系列资料分析,建立了自激励门限自回归模型(SETAR MODEL),采用9个参数有效地描述了水稻需水量各个生育期在多种气象及其它影响因子的作用下的周期变化的非线性复杂系统.模型拟合与预测精度较高,可在灌区规划管理与优化水稻灌溉制度中应用.

  1. Is the Quantity Theory of Money Useful in Forecasting U.S. Inflation?

    DEFF Research Database (Denmark)

    Lanne, Markku; Luoto, Jani; Nyberg, Henri

    We propose a new simple model incorporating the implication of the quantity theory of money that money growth and ináation should move one for one in the long run, and, hence, ináation should be predictable by money growth. The model Öts postwar U.S. data well, and beats common univariate benchma...... models in forecasting ináation. Moreover, this evidence is quite robust, and predictability is found also in the Great moderation period. The detected predictability of ináation by money growth lends support to the quantity theory....

  2. The Fuzzy Economic Order Quantity Problem with a Finite Production Rate and Backorders

    Directory of Open Access Journals (Sweden)

    Kaj-Mikael Björk

    2012-01-01

    Full Text Available The track of developing Economic Order Quantity (EOQ models with uncertainties described as fuzzy numbers has been very lucrative. In this paper, a fuzzy Economic Production Quantity (EPQ model is developed to address a specific problem in a theoretical setting. Not only is the production time finite, but also backorders are allowed. The uncertainties, in the industrial context, come from the fact that the production availability is uncertain as well as the demand. These uncertainties will be handled with fuzzy numbers and the analytical solution to the optimization problem will be obtained. A theoretical example from the process industry is also given to illustrate the new model.

  3. The investigation of prostatic calcifications using μ-PIXE analysis and their dosimetric effect in low dose rate brachytherapy treatments using Geant4

    Science.gov (United States)

    Pope, D. J.; Cutajar, D. L.; George, S. P.; Guatelli, S.; Bucci, J. A.; Enari, K. E.; Miller, S.; Siegele, R.; Rosenfeld, A. B.

    2015-06-01

    Low dose rate brachytherapy is a widely used modality for the treatment of prostate cancer. Most clinical treatment planning systems currently in use approximate all tissue to water, neglecting the existence of inhomogeneities, such as calcifications. The presence of prostatic calcifications may perturb the dose due to the higher photoelectric effect cross section in comparison to water. This study quantitatively evaluates the effect of prostatic calcifications on the dosimetric outcome of brachytherapy treatments by means of Monte Carlo simulations and its potential clinical consequences. Four pathological calcification samples were characterised with micro-particle induced x-ray emission (μ-PIXE) to determine their heavy elemental composition. Calcium, phosphorus and zinc were found to be the predominant heavy elements in the calcification composition. Four clinical patient brachytherapy treatments were modelled using Geant4 based Monte Carlo simulations, in terms of the distribution of brachytherapy seeds and calcifications in the prostate. Dose reductions were observed to be up to 30% locally to the calcification boundary, calcification size dependent. Single large calcifications and closely placed calculi caused local dose reductions of between 30-60%. Individual calculi smaller than 0.5 mm in diameter showed minimal dosimetric impact, however, the effects of small or diffuse calcifications within the prostatic tissue could not be determined using the methods employed in the study. The simulation study showed a varying reduction on common dosimetric parameters. D90 showed a reduction of 2-5%, regardless of calcification surface area and volume. The parameters V100, V150 and V200 were also reduced by as much as 3% and on average by 1%. These reductions were also found to relate to the surface area and volume of calcifications, which may have a significant dosimetric impact on brachytherapy treatment, however, such impacts depend strongly on specific factors

  4. SU-D-204-01: A Methodology Based On Machine Learning and Quantum Clustering to Predict Lung SBRT Dosimetric Endpoints From Patient Specific Anatomic Features

    Energy Technology Data Exchange (ETDEWEB)

    Lafata, K; Ren, L; Wu, Q; Kelsey, C; Hong, J; Cai, J; Yin, F [Duke University Medical Center, Durham, NC (United States)

    2016-06-15

    Purpose: To develop a data-mining methodology based on quantum clustering and machine learning to predict expected dosimetric endpoints for lung SBRT applications based on patient-specific anatomic features. Methods: Ninety-three patients who received lung SBRT at our clinic from 2011–2013 were retrospectively identified. Planning information was acquired for each patient, from which various features were extracted using in-house semi-automatic software. Anatomic features included tumor-to-OAR distances, tumor location, total-lung-volume, GTV and ITV. Dosimetric endpoints were adopted from RTOG-0195 recommendations, and consisted of various OAR-specific partial-volume doses and maximum point-doses. First, PCA analysis and unsupervised quantum-clustering was used to explore the feature-space to identify potentially strong classifiers. Secondly, a multi-class logistic regression algorithm was developed and trained to predict dose-volume endpoints based on patient-specific anatomic features. Classes were defined by discretizing the dose-volume data, and the feature-space was zero-mean normalized. Fitting parameters were determined by minimizing a regularized cost function, and optimization was performed via gradient descent. As a pilot study, the model was tested on two esophageal dosimetric planning endpoints (maximum point-dose, dose-to-5cc), and its generalizability was evaluated with leave-one-out cross-validation. Results: Quantum-Clustering demonstrated a strong separation of feature-space at 15Gy across the first-and-second Principle Components of the data when the dosimetric endpoints were retrospectively identified. Maximum point dose prediction to the esophagus demonstrated a cross-validation accuracy of 87%, and the maximum dose to 5cc demonstrated a respective value of 79%. The largest optimized weighting factor was placed on GTV-to-esophagus distance (a factor of 10 greater than the second largest weighting factor), indicating an intuitively strong

  5. Effects of Different Long-term Fertilization Models on Culturable Microbial Quantity and Enzyme Activities of Lime Concretion Black Soil%长期不同施肥模式对砂姜黑土可培养微生物数量和酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    张向前; 陈欢; 乔玉强; 曹承富; 杜世州; 李玮; 赵竹

    2016-01-01

    Based on long-term located fertilization experiment (year 1981—) in lime concretion black soil area, we studied the effects of without fertilizer application CK, long-term application of single chemical fertilizer NPK, long-term application of single organic fertilizer M, long-term mixed application of organic and chemical fertilizer MNPK (with the same amount of nitrogen) and HMNPK (with the larger amount of nitrogen) on culturable microbial quantity and enzyme activities in soil, in order to reveal the response mechanism of soil microbial quantity and enzyme activities to different fertilization models, and to provide scientific basis and theoretical help for improving lime concretion black soil fertility and quality. The quantity of bacteria, fungi, actinomycetes and Azotobacter of CK was lower than that of other fertilization treatments, and the quantity of bacteria, actinomycetes and Azotobacter of M was significantly higher than that of NPK at middle of filling stage, while the difference in the quantity of fungi between M and NPK was insignificant. The quantity of bacteria, fungi and actinomycetes of MNPK and HMNPK was higher than that of NPK and M, compared to NPK and M, MNPK increased the quantity of bacteria, fungi and actinomycetes by 47.0%, 21.1%, 32.1% and 23.2%, 11.7%, 20.2%, respectively. The difference in the quantity of bacteria, fungi and actinomycetes between MNPK and HMNPK was insignificant at middle of filling stage, while the quantity of Azotobacter of MNPK was higher than that of HMNPK. The activities of invertase, dehydrogenase, acidic and neutral phosphatase and protease of M were higher than that of NPK at middle of filling stage, and increased by 20.9%, 22.1%, 17.7%, 18.4%, 10.0%, respectively. When compared to long-term application of single chemical fertilizer and organic fertilizer, the treatment of long-term mixed application of organic and chemical fertilizer obviously increased the activities of soil invertase, dehydrogenase

  6. Dosimetric evaluation of whole-breast radiation therapy: Clinical experience

    Energy Technology Data Exchange (ETDEWEB)

    Osei, Ernest, E-mail: ernest.osei@grhosp.on.ca [Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, Ontario (Canada); Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario (Canada); Department of Systems Design, University of Waterloo, Waterloo, Ontario (Canada); Darko, Johnson [Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, Ontario (Canada); Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario (Canada); Fleck, Andre [Department of Medical Physics, Grand River Regional Cancer Centre, Kitchener, Ontario (Canada); White, Jana [Department of Radiation Therapy, Grand River Regional Cancer Centre, Kitchener, Ontario (Canada); Kiciak, Alexander; Redekop, Rachel [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario (Canada); Gopaul, Darin [Department of Radiation Oncology, Grand River Regional Cancer Centre, Kitchener, Ontario (Canada)

    2015-01-01

    Radiation therapy of the intact breast is the standard therapy for preventing local recurrence of early-stage breast cancer following breast conservation surgery. To improve patient standard of care, there is a need to define a consistent and transparent treatment path for all patients that reduces significance variations in the acceptability of treatment plans. There is lack of consistency among institutions or individuals about what is considered an acceptable treatment plan: target coverage vis-à-vis dose to organs at risk (OAR). Clinical trials usually resolve these issues, as the criteria for an acceptable plan within the trial (target coverage and doses to OAR) are well defined. We developed an institutional criterion for accepting breast treatment plans in 2006 after analyzing treatment data of approximately 200 patients. The purpose of this article is to report on the dosimetric review of 623 patients treated in the last 18 months to evaluate the effectiveness of the previously developed plan acceptability criteria and any possible changes necessary to further improve patient care. The mean patient age is 61.6 years (range: 25.2 to 93.0 years). The mean breast separation for all the patients is 21.0 cm (range: 12.4 to 34.9 cm), and the mean planning target volume (PTV-eval) (breast volume for evaluation) is 884.0 cm{sup 3} (range: 73.6 to 3684.6 cm{sup 3}). Overall, 314 (50.4%) patients had the disease in the left breast and 309 (49.6%) had it in the right breast. A total of 147 (23.6%) patients were treated using the deep inspiration breath-hold (DIBH) technique. The mean normalized PTV-eval receiving at least 92% (V{sub 92%} {sub PD}) and 95% (V{sub 95%} {sub PD}) of the prescribed dose (PD) are more than 99% and 97%, respectively, for all patients. The mean normalized PTV-eval receiving at least 105% (V{sub 105%} {sub PD}) of the PD is less than 1% for all groups. The mean homogeneity index (HI), uniformity index (UI), and conformity index (CI) for the

  7. A dosimetric characterization of a novel linear accelerator collimator

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, C. M.; Weston, S. J., E-mail: steve.weston@leedsth.nhs.uk; Cosgrove, V. C. [Leeds Cancer Centre, Bexley Wing, St. James’ University Hospital, Leeds LS9 7TF (United Kingdom); Thwaites, D. I. [Institute of Medical Physics, School of Physics, University of Sydney, Sydney NSW 2006, Australia and Division of Medical Physics, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2014-03-15

    Purpose: The aim of this work is to characterize a new linear accelerator collimator which contains a single pair of sculpted diaphragms mounted orthogonally to a 160 leaf multileaf collimator (MLC). The diaphragms have “thick” regions providing full attenuation and “thin” regions where attenuation is provided by both the leaves and the diaphragm. The leaves are mounted on a dynamic leaf guide allowing rapid leaf motion and leaf travel over 350 mm. Methods: Dosimetric characterization, including assessment of leaf transmission, leaf tip transmission, penumbral width, was performed in a plotting tank. Head scatter factor was measured using a mini-phantom and the effect of leaf guide position on output was assessed using a water phantom. The tongue and groove effect was assessed using multiple exposures on radiochromic film. Leaf reproducibility was assessed from portal images of multiple abutting fields. Results: The maximum transmission through the multileaf collimator is 0.44% at 6 MV and 0.52% at 10 MV. This reduced to 0.22% and 0.27%, respectively, when the beam passes through the dynamic leaf guide in addition to the MLC. The maximum transmission through the thick part of the diaphragm is 0.32% and 0.36% at 6 and 10 MV. The combination of leaf and diaphragm transmission ranges from 0.08% to 0.010% at 6 MV and 0.10% to 0.14% depending on whether the shielding is through the thick or thin part of the diaphragm. The off-axis intertip transmission for a zero leaf gap is 2.2% at 6 and 10 MV. The leaf tip penumbra for a 100 × 100 mm field ranges from 5.4 to 4.3 mm at 6 and 10 MV across the full range of leaf motion when measured in the AB direction, which reduces to 4.0–3.4 mm at 6 MV and 4.5–3.8 mm at 10 MV when measured in the GT direction. For a 50 × 50 mm field, the diaphragm penumbra ranges from 4.3 to 3.7 mm at 6 MV and 4.5 to 4.1 mm at 10 MV in the AB direction and 3.7 to 3.2 mm at 6 MV and 4.2 to 3.7 mm when measured in the GT direction. The

  8. Hwa measurement of turbulent diffusion of a scalar quantity

    Directory of Open Access Journals (Sweden)

    Antoš Pavel

    2012-04-01

    Full Text Available The paper deals with simultaneous measurement of the velocity and the scalar quantity by means of hot-wire anemometry. Statistical moments of the scalar quantity fluctuations can be obtained employing a dual hot-wire probe. An evaluation procedure of the quantity mean values and fluctuations is described. Results from the molar concentration measurement in binary-gas mixture are shown.

  9. On the History of Quantity Calculus and the International System

    Science.gov (United States)

    de Boer, J.

    1995-01-01

    A brief presentation is given of the most important developments in the history of quantity calculus. Starting with the early introduction of the concept "physical quantity" by Maxwell in his work on electricity and magnetism, attention is focused in particular on the foundations of the calculus with physical quantities given by Wallot in the 1920s. For illustration and better understanding of the praxis of quantity calculus, special attention is paid to the three- and four-dimensional systems of physical quantities used for theoretical description in the fields of electricity and magnetism. Special emphasis is placed on understanding controversies and confusion caused by differences in interpretation of the concepts "quantity" and "unit" in physical language and in the mathematical description of physical phenomena. A short presentation is given of the further development of various studies on the algebraic structure and the axiomatic foundation of the calculus with physical quantities developed by Landolt, Stille, Fleischmann and others. Quantity calculus constituted the basis for obtaining consensus on the introduction of the International System of Units (SI) and allowed the formulation of international standards on definitions and symbols for quantities and units by the various international scientific and standardizing organizations.

  10. Quantity Discount Scheme in Supply Chain under Asymmetric Information

    Institute of Scientific and Technical Information of China (English)

    LI Ji-bin; PENG Zuo-he

    2007-01-01

    Quantity discount scheme plays an important role in supply chain management. The different quantity discount schemes under symmetric (full) information and asymmetric information, are analyzed by using principal-agent and optimal control theory. As a result, the research reveals that the optimal quantity discount solution under symmetric information is a special case of that under asymmetric information. At the same price, the critical value of quantity discount under asymmetric information is much lower than that under asymmetric information. Therefore, this leads to less cost for retailers and smaller profit for their supplier.

  11. Quantity of cholesterol in butter from Zagreb market

    Directory of Open Access Journals (Sweden)

    Željka Cvrtila

    2001-01-01

    Full Text Available In this article the quantity of cholesterol in butter - a representative of dairy products with known high quantity of milk fat, is determined. The results show that the quantity of milk fats for the butter samples from domestic production (n=17 was 83.9 %, and from the industrial production (n=5 85.2 %. Average cholesterol quantities, in before mentioned samples, were 227 mg/100g or 22 mg of cholesterol per 100 g of sample. The results show that the increase of milk fats does not strictly influence cholesterol increase in the individual butter sample.

  12. Dosimetric study and assessment of objective functions developed in IMRT; etude dosimetrique et evaluation de fonctions objectives developpees en RCMI

    Energy Technology Data Exchange (ETDEWEB)

    Servagi-Vernat, S.; Bosset, J.F. [Service de radiotherapie, CHU IFRC, Besancon (France); Ali, D.; Giraud, P. [Hopital europeen Georges-Pompidou, Paris (France); Viard, R. [Aquilab SAS, Loos-lez-Lille (France); Fenoglietto, P. [Centre Rene-Gauducheau, Nantes (France); Lisbona, A.; Zetkin, S. [Institut Curie, Paris (France)

    2011-10-15

    The authors report a prospective and comparative analysis of the main dosimetric, physical, biological and probabilistic parameters concerning tumour target volumes and organs at risk for three new types of intensity-modulated conformational radiotherapy (IMRT): helical tomo-therapy, VMat-type dynamic arc-therapy (volumetric modulated ar therapy), and RapidArc-type dynamic arc-therapy. They also report the validation of new predictive dosimetric parameters in patients with ENT cancers. Short communication

  13. Lie symmetry and conserved quantity of fractional Lagrange system based on El-Nabulsi models%基于 El-Nabulsi 模型的分数阶Lagrange 系统的 Lie 对称性与守恒量

    Institute of Scientific and Technical Information of China (English)

    张孝彩; 张毅

    2016-01-01

    The Lie symmetry and the conserved quantity of fractional Lagrange system based on El-Nabulsi models are studied.Firstly,the D’Alembert-Lagrange principle of the El-Nabulsi models is de-duced based on the fractional action-like variational problem which is expanded by the Riemann-Liouville integral,and the differential equations of motion of the system are obtained.Secondly,the definition and the criterion of the Lie symmetry are given,the determination equations of the Lie symmetry of the system are established,and the generalized Hojman theorem is put forward.At the same time,the existence condition and the form of the generalized Hojman conserved quantity are obtained.Then,the generalized Noether theorem is established,the existence condition and the form of the Noether conserved quantity led by the Lie symmetry are given.Finally,two examples are given to illustrate the application of the re-sults.%研究基于 El-Nabulsi 模型的分数阶 Lagrange 系统的 Lie 对称性与守恒量。基于按 Riemann-Liouville 积分拓展的类分数阶变分问题导出 El-Nabulsi 模型的 D’Alembert-Lagrange 原理,得到系统的运动微分方程;给出分数阶 Lie 对称性的定义和判据,建立了 Lie 对称性确定方程,并提出广义 Hojman 定理,给出广义 Hojman 守恒量存在的条件及其形式;最后,建立了广义 Noether 定理,给出分数阶 Lie 对称性导致 Noether 守恒量的条件及其形式,并给出两个算例以说明结果的应用。

  14. BIM implementation in a New Zealand consulting quantity surveying practice

    Directory of Open Access Journals (Sweden)

    Curtis Harrison

    2015-07-01

    Full Text Available 5D BIM - generating cost data via the building information modelling (BIM process - has the potential to be used by quantity surveyors (QSs to streamline their workflows and increase their provision of a quality service. Consultant QSs experienced in the use of 5D BIM, from the New Zealand office of a large global practice, were interviewed on their perceptions of the benefits of, and barriers to, 5D BIM implementation within their firm. Findings suggest that 5D BIM has numerous benefits over traditional methods, chiefly through the increased efficiency and visualisation that BIM provides, along with the rapid identification of design changes. However, realisation of these perceived benefits is limited to date, due to several barriers hindering 5D BIM implementation: incomplete design and insufficient model object data in the BIM model; a lack of standards to facilitate electronic measurement; legal issues, and a lack of government support. Increasing 5D BIM implementation, in tandem with increasing use of collaborative project working through integrated project delivery, will, however, facilitate these benefits being achieved to a far greater extent in the future. Further research is recommended to identify the BIM skills which QSs will need in the future to reach the full potential of 5D BIM.

  15. A Stochastic Decision Support System for Economic Order Quantity Problem

    Directory of Open Access Journals (Sweden)

    Amir Yousefli

    2012-01-01

    Full Text Available Improving decisions efficiency is one of the major concerns of the decision support systems. Specially in the uncertain environment, decision support systems could be implemented efficiently to simplify decision making process. In this paper stochastic economic order quantity (EOQ problem is investigated in which decision variables and objective function are uncertain in nature and optimum probability distribution functions of them are calculated through a geometric programming model. Obtained probability distribution functions of the decision variables and the objective function are used as optimum knowledge to design a new probabilistic rule base (PRB as a decision support system for EOQ model. The developed PRB is a new type of the stochastic rule bases that can be used to infer optimum or near optimum values of the decision variables and the objective function of the EOQ model without solving the geometric programming problem directly. Comparison between the results of the developed PRB and the optimum solutions which is provided in the numerical example illustrates the efficiency of the developed PRB.

  16. Dosimetric properties of a proton beamline dedicated to the treatment of ocular disease

    Energy Technology Data Exchange (ETDEWEB)

    Slopsema, R. L., E-mail: rslopsema@floridaproton.org; Mamalui, M.; Yeung, D.; Malyapa, R.; Li, Z. [University of Florida Proton Therapy Institute, 2015 North Jefferson Street, Jacksonville, Florida 32205 (United States); Zhao, T. [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, St. Louis, Missouri 63110 (United States)

    2014-01-15

    Purpose: A commercial proton eyeline has been developed to treat ocular disease. Radiotherapy of intraocular lesions (e.g., uveal melanoma, age-related macular degeneration) requires sharp dose gradients to avoid critical structures like the macula and optic disc. A high dose rate is needed to limit patient gazing times during delivery of large fractional dose. Dose delivery needs to be accurate and predictable, not in the least because current treatment planning algorithms have limited dose modeling capabilities. The purpose of this paper is to determine the dosimetric properties of a new proton eyeline. These properties are compared to those of existing systems and evaluated in the context of the specific clinical requirements of ocular treatments. Methods: The eyeline is part of a high-energy, cyclotron-based proton therapy system. The energy at the entrance of the eyeline is 105 MeV. A range modulator (RM) wheel generates the spread-out Bragg peak, while a variable range shifter system adjusts the range and spreads the beam laterally. The range can be adjusted from 0.5 up to 3.4 g/cm{sup 2}; the modulation width can be varied in steps of 0.3 g/cm{sup 2} or less. Maximum field diameter is 2.5 cm. All fields can be delivered with a dose rate of 30 Gy/min or more. The eyeline is calibrated according to the IAEA TRS-398 protocol using a cylindrical ionization chamber. Depth dose distributions and dose/MU are measured with a parallel-plate ionization chamber; lateral profiles with radiochromic film. The dose/MU is modeled as a function of range, modulation width, and instantaneous MU rate with fit parameters determined per option (RM wheel). Results: The distal fall-off of the spread-out Bragg peak is 0.3 g/cm{sup 2}, larger than for most existing systems. The lateral penumbra varies between 0.9 and 1.4 mm, except for fully modulated fields that have a larger penumbra at skin. The source-to-axis distance is found to be 169 cm. The dose/MU shows a strong dependence

  17. On the Hojman conservation quantities in Cosmology

    CERN Document Server

    Paliathanasis, A; Capozziello, S

    2016-01-01

    We discuss the application of the Hojmans Symmetry Approach for the determination of conservation laws in Cosmology, which has been recently applied by various authors in different cosmological models. We show that Hojman's method for regular Hamiltonian systems, where the Hamiltonian function is one of the involved equations of the system, is equivalent to the application of Noether's Theorem for generalized transformations. That means that for minimally-coupled scalar field cosmology or other modified theories which are conformally related with scalar-field cosmology, like $f(R)$ gravity, the application of Hojman's method provide us with the same results with that of Noether's theorem. Moreover we study the special Ansatz. $\\phi\\left( t\\right) =\\phi\\left( a\\left( t\\right) \\right) $, which has been introduced for a minimally-coupled scalar field, and we study the Lie and Noether point symmetries for the reduced equation. We show that under this Ansatz, the unknown function of the model cannot be constrained...

  18. Household Water Quantity and Health: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Rachel D. Stelmach

    2015-05-01

    Full Text Available While the quantity of water used in the home is thought to be an important determinant of health, much of the evidence relies on using water access as a proxy for quantity. This review examines the health effects of household water quantity using studies that directly measured water quantity. We searched MEDLINE, EMBASE, the Cochrane Library, Web of Science, and article reference lists. Eligible studies included experimental and observational studies that measured a difference in water quantity and quantified an association between water quantity and health outcomes. 21 studies, divided into six of the many possible water-quantity associated outcomes, met the eligibility criteria. Due to heterogeneity in designs, settings, methods, and outcomes, a meta-analysis was inappropriate. Overall results showed a positive association between water quantity and health outcomes, but the effect depended on how the water was used. Increased water usage for personal hygiene was generally associated with improved trachoma outcomes, while increased water consumption was generally associated with reduced gastrointestinal infection and diarrheal disease and improved growth outcomes. In high-income countries, increased water consumption was associated with higher rates of renal cell carcinoma and bladder cancer but not associated with type II diabetes, cardiac-related mortality, or all-cause mortality.

  19. Some Intensive and Extensive Quantities in High-Energy Collisions

    CERN Document Server

    Tawfik, A

    2013-01-01

    We review the evolution of some statistical and thermodynamical quantities measured in difference sizes of high-energy collisions at different energies. We differentiate between intensive and extensive quantities and discuss the importance of their distinguishability in characterizing possible critical phenomena of nuclear collisions at various energies with different initial conditions.

  20. Effects of Quantity and Quality Instructions on Brainstorming

    Science.gov (United States)

    Paulus, Paul B.; Kohn, Nicholas W.; Arditti, Lauren E.

    2011-01-01

    One of the basic presumptions of brainstorming is that a focus on generating a large number of ideas enhances both the number of ideas generated and the number of good ideas (original and useful). Prior research has not clearly demonstrated the utility of such a quantity focus in comparison to a condition in which quantity is not emphasized. There…

  1. 48 CFR 14.212 - Economic purchase quantities (supplies).

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Economic purchase... purchase quantities (supplies). Contracting officers shall comply with the economic purchase quantity... provision at 52.207-4, Economic Purchase Quantity—Supplies, and 7.204 for guidance on handling responses...

  2. Household water quantity and health: a systematic review.

    Science.gov (United States)

    Stelmach, Rachel D; Clasen, Thomas

    2015-05-28

    While the quantity of water used in the home is thought to be an important determinant of health, much of the evidence relies on using water access as a proxy for quantity. This review examines the health effects of household water quantity using studies that directly measured water quantity. We searched MEDLINE, EMBASE, the Cochrane Library, Web of Science, and article reference lists. Eligible studies included experimental and observational studies that measured a difference in water quantity and quantified an association between water quantity and health outcomes. 21 studies, divided into six of the many possible water-quantity associated outcomes, met the eligibility criteria. Due to heterogeneity in designs, settings, methods, and outcomes, a meta-analysis was inappropriate. Overall results showed a positive association between water quantity and health outcomes, but the effect depended on how the water was used. Increased water usage for personal hygiene was generally associated with improved trachoma outcomes, while increased water consumption was generally associated with reduced gastrointestinal infection and diarrheal disease and improved growth outcomes. In high-income countries, increased water consumption was associated with higher rates of renal cell carcinoma and bladder cancer but not associated with type II diabetes, cardiac-related mortality, or all-cause mortality.

  3. Study on Human Capital Valve Quantity Model and Investment Featuers

    Institute of Scientific and Technical Information of China (English)

    Chen Peian; Li Yujiang; Li Zhen

    2005-01-01

    In this paper, human capital is considered a kind of goods in terms of investment. Basic consumption and profit margin are the two important components of human capital goods value. Compared with that of the material capital, the human capital consumption has the following features.The importance of human capital investment determined by the supply-demand mechanism, is growing gradually; The course of investment and return takes a long period of time; Human capital is characterized by strong technicality and weak negotiability; The investment profit margin is changeable and discriminating.

  4. Dosimetric characterisation of Brazilian natural stones using the thermally stimulated exoelectron emission technique

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, F.D.G.; Cecatti, S.G.P.; Caldas, L.V.E

    2002-07-01

    A thermally stimulated exoelectron emission (TSEE) measuring system developed and constructed at IPEN was used to verify the feasibility of the use of Brazilian natural semi-precious stones, such as jasper, amethyst, agate (blue and rose) and quartz (rose and white) for gamma and X radiation detection. Its counting system consists of a 2p windowless gas-flow proportional counter, and the heating system is formed by a temperature programmer that provides linear heating of the samples. The samples were tested in gamma and in X radiation beams and evaluated in relation to their main dosimetric characteristics, as TSEE glow curves, calibration curves and energy dependence. The TSEE results are compared with those of thermoluminescence. The results obtained show the usefulness of Brazilian natural stones as dosimetric materials, using the thermoluminescence and thermally stimulated exoelectron emission techniques. (author)

  5. Dosimetric feasibility study for an extracorporeal BNCT application on liver metastases at the TRIGA Mainz

    Energy Technology Data Exchange (ETDEWEB)

    Blaickner, M., E-mail: matthias.blaickner@ait.ac.at [Health and Environment Department-Molecular Medicine, AIT Austrian Institute of Technology GmbH, Muthgasse 11, A-1190 Vienna (Austria); Kratz, J.V. [Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55128 Mainz (Germany); Minouchehr, S.; Otto, G. [Transplantationschirurgie, Universitaetsklinikum Mainz, Langenbeckstr.1, D-55131 Mainz (Germany); Schmidberger, H. [Klinik und Poliklinik fuer Radioonkologie und Strahlentherapie, Universitaetsklinikum Mainz, Langenbeckstr.1, D-55131 Mainz (Germany); Schuetz, C.; Vogtlaender, L. [Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55128 Mainz (Germany); Wortmann, B. [Evonik Energy Services GmbH Essen, Ruettenscheider Str. 1-3, D-45128 Essen (Germany); Hampel, G. [Institut fuer Kernchemie, Johannes Gutenberg-Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55128 Mainz (Germany)

    2012-01-15

    This study investigates the dosimetric feasibility of Boron Neutron Capture Therapy (BNCT) of explanted livers in the thermal column of the research reactor in Mainz. The Monte Carlo code MCNP5 is used to calculate the biologically weighted dose for different ratios of the {sup 10}B-concentration in tumour to normal liver tissue. The simulation results show that dosimetric goals are only partially met. To guarantee effective BNCT treatment the organ has to be better shielded from all gamma radiation. - Highlights: Black-Right-Pointing-Pointer Monte Carlo simulations demonstrate the potential for BNCT treatment at TRIGA Mainz. Black-Right-Pointing-Pointer Simulation shows the necessity of gamma shielding for the organ from all sides. Black-Right-Pointing-Pointer Secondary photons induced within the graphite contribute considerably to gamma dose.

  6. Validation of dosimetric field matching accuracy from proton therapy using a robotic patient positioning system.

    Science.gov (United States)

    Farr, Jonathan B; O'Ryan-Blair, Avril; Jesseph, Frederick; Hsi, Wen-Chien; Allgower, Chris E; Mascia, Anthony E; Thornton, Allan F; Schreuder, Andreas N

    2010-04-12

    Large area, shallow fields are well suited to proton therapy. However, due to beam production limitations, such volumes typically require multiple matched fields. This is problematic due to the relatively narrow beam penumbra at shallow depths compared to electron and photon beams. Therefore, highly accurate dose planning and delivery is required. As the dose delivery includes shifting the patient for matched fields, accuracy at the 1-2 millimeter level in patient positioning is also required. This study investigates the dosimetric accuracy of such proton field matching by an innovative robotic patient positioner system (RPPS). The dosimetric comparisons were made between treatment planning system calculations, radiographic film and ionization chamber measurements. The results indicated good agreement amongst the methods and suggest that proton field matching by a RPPS is accurate and efficient.

  7. Dosimetric systems developed in Brazil for the radiation processes quality control

    Energy Technology Data Exchange (ETDEWEB)

    Galante, Ana Maria Sisti; Campos, Leticia Lucente, E-mail: sgalante@ipen.b, E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    In order to apply new technologies to the industrial processing of materials aiming economy, efficiency, speed and high quality, ionizing radiation has been used in medicine, archaeology, chemistry, food preservation and other areas. For this reason, the dosimetry area looks for improve current dosimeters and develop new materials for application on quality control of these processes. In Brazil, the research in the dosimetry area occurs with great speed providing many different dosimetric systems. The chemical dosimetry is the most used technique in routine dosimetry, which requires fast and accurate responses. This technique involves determination of absorbed dose by measuring chemical changes radiation induced in the materials. Different dosimetric systems were developed at IPEN for application on radiation process quality and all of them present excellent results; the low cost of these materials allows a more effective dose control, therefore, a larger area or volume can be monitored. (author).

  8. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN/MG), Belo Horizonte, MG (Brazil)], e-mail: gas@cdtn.br, e-mail: pls@cdtn.br, e-mail: fcp@cdtn.br, e-mail: lcmb@cdtn.br, e-mail: pabloag@cdtn.br

    2009-07-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  9. An Algebraic Approach to Unital Quantities and their Measurement

    Science.gov (United States)

    Domotor, Zoltan; Batitsky, Vadim

    2016-06-01

    The goals of this paper fall into two closely related areas. First, we develop a formal framework for deterministic unital quantities in which measurement unitization is understood to be a built-in feature of quantities rather than a mere annotation of their numerical values with convenient units. We introduce this idea within the setting of certain ordered semigroups of physical-geometric states of classical physical systems. States are assumed to serve as truth makers of metrological statements about quantity values. A unital quantity is presented as an isomorphism from the target system's ordered semigroup of states to that of positive reals. This framework allows us to include various derived and variable quantities, encountered in engineering and the natural sciences. For illustration and ease of presentation, we use the classical notions of length, time, electric current and mean velocity as primordial examples. The most important application of the resulting unital quantity calculus is in dimensional analysis. Second, in evaluating measurement uncertainty due to the analog-to-digital conversion of the measured quantity's value into its measuring instrument's pointer quantity value, we employ an ordered semigroup framework of pointer states. Pointer states encode the measuring instrument's indiscernibility relation, manifested by not being able to distinguish the measured system's topologically proximal states. Once again, we focus mainly on the measurement of length and electric current quantities as our motivating examples. Our approach to quantities and their measurement is strictly state-based and algebraic in flavor, rather than that of a representationalist-style structure-preserving numerical assignment.

  10. SU-E-T-651: Quantification of Dosimetric Accuracy of Respiratory Gated Stereotactic Body Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thiyagarajan, Rajesh; Vikraman, S; Maragathaveni, S; Dhivya, N; Kataria, Tejinder [Medanta The Medicity, Gurgaon, Haryana (India); Nambiraj, N Arunai; Sigamani, Ashokkumar [VIT University, Vellore, Tamil Nadu (India); Sinha, Sujit Nath [Nayati Healathcare and Research Pvt Ltd, Mathura, Uttar pradesh (India); Yadav, Girigesh; Raman, Kothanda [Rajiv Gandhi Cancer Institute & Research Centre, Gurgaon, Haryana (India)

    2015-06-15

    Purpose: To quantify the dosimetric accuracy of respiratory gated stereotactic body radiation therapy delivery using dynamic thorax phantom. Methods: Three patients with mobile target (2 lung, 1liver) were chosen. Retrospective 4DCT image sets were acquired for using Varian RPM system. An in-house MATLAB program was designed for MIP, MinIP and AvgIP generation. ITV was contoured on MIP image set for lung patients and on MinIP for liver patient. Dynamic IMRT plans were generated on selected phase bin image set in Eclipse (v10.0) planning system. CIRS dynamic thorax phantom was used to perform the dosimetric quality assurance. Patient breathing pattern file from RPM system was converted to phantom compatible file by an in-house MATLAB program. This respiratory pattern fed to the CIRS dynamic thorax phantom. 4DCT image set was acquired for this phantom using patient breathing pattern. Verification plans were generated using patient gating window and delivered on the phantom. Measurements were carried out using with ion chamber and EBT2 film. Exposed films were analyzed and evaluated in FilmQA software. Results: The stability of gated output in comparison with un-gated output was within 0.5%. The Ion chamber measured and TPS calculated dose compared for all the patients. The difference observed was 0.45%, −0.52% and −0.54 for Patient 1, Patient2 and Patient 3 respectively.Gamma value evaluated from EBT film shows pass rates from 92.41% to 99.93% for 3% dose difference and 3mm distance to agreement criteria. Conclusion: Dosimetric accuracy of respiratory gated SBRT delivery for lung and liver was dosimetrically acceptable. The Ion chamber measured dose was within 0.203±0.5659% of the expected dose. Gamma pass rates were within 96.63±3.84% of the expected dose.

  11. X-Ray Attenuation and Absorption for Materials of Dosimetric Interest

    Science.gov (United States)

    SRD 126 X-Ray Attenuation and Absorption for Materials of Dosimetric Interest (Web, free access)   Tables and graphs of the photon mass attenuation coefficient and the mass energy-absorption coefficient are presented for all of the elements Z = 1 to 92, and for 48 compounds and mixtures of radiological interest. The tables cover energies of the photon (x-ray, gamma ray, bremsstrahlung) from 1 keV to 20 MeV.

  12. Verification criteria on the reliability of personal dosimetric services from x and gamma radiations

    CERN Document Server

    Borasi, G; Kaftal, S

    1990-01-01

    The paper presents the methods used by Working Group ENEA-EDP (Experts in Personal Dosimetry) to control the reliability of the Dosimetric Services operating in Italy and asking for the above controls on voluntary basis. Testing and irradiation test methods are explained as well as the evaluation criteria. The paper includes suggestions and guide-lines to gain the status of 'Reliable Service'. Technical equipment and operating procedures needed to pass the test are also illustrated.

  13. Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Pedagogical University, Czestochowa (Poland)]|[Institute of Materials, Lvov (Ukraine)

    1997-12-31

    The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author). 16 refs, 1 tab.

  14. Dosimetric impact of orthopedic metal artifact reduction (O-MAR) on spine SBRT patients.

    Science.gov (United States)

    Shen, Zhilei Liu; Xia, Ping; Klahr, Paul; Djemil, Toufik

    2015-09-01

    The dosimetric impact of orthopedic metal artifact reduction (O-MAR) on spine SBRT patients has not been comprehensively studied, particularly with spinal prostheses in high-dose gradient regions. Using both phantom and patient datasets, we investigated dosimetric effects of O-MAR in combination of various metal locations and dose calculation algorithms. A physical phantom, with and without a titanium insert, was scanned. A clinical patient plan was applied to the artifact-free reference, non-O-MAR, and O-MAR phantom images with the titanium located either inside or outside of the tumor. Subsequently, five clinical patient plans were calculated with pencil beam and Monte Carlo (iPlan) on non-O-MAR and O-MAR patient images using an extended CT-density table. The dose differences for phantom plans and patient plans were analyzed using dose distributions, dose-volume histograms (DVHs), gamma index, and selected dosimetric endpoints. From both phantom plans and patient plans, O-MAR did not affect dose distributions and DVHs while minimizing metal artifacts. Among patient plans, we found that, when the same dose calculation method was used, the difference in the dosimetric endpoints between non-O-MAR and O-MAR datasets were small. In conclusion, for spine SBRT patients with spinal prostheses, O-MAR image reconstruction does not affect dose calculation accuracy while minimizing metal artifacts. Therefore, O-MAR images can be safely used for clinical spine SBRT treatment planning. PACS numbers: 87.53.Bn, 87.55.K-, 87.57.Q-, 87.57.cp.

  15. Dynamic Coding of Signed Quantities in Cortical Feedback Circuits

    Directory of Open Access Journals (Sweden)

    Dana eBallard

    2012-08-01

    Full Text Available In the early sensory and motor areas of the cortex, individual neurons transmit information about specific sensory features via a peaked response. This concept has been crystallized as `labeled lines,' to denote that axons communicate the specific properties of their sensory or motor parent cell. Such cells also can be characterized as being polarized, that is, as representing a signed quantity that is either positive or negative. We show in a model simulation that there are two important consequences when learning receptive fields using such signed codings in circuits that subtract different inputs. The first is that, in feedback circuits using labeled lines, such arithmetic operations need to be distributed across multiple distinct pathways. The second consequence is that such pathways must be necessarily dynamic, i.e. that synapses can grow and retract when forming receptive fields. The model monitors the breaking and growing of new circuit connections when their synapses need to change polarities and predicts that the rate of such changes should be inversely correlated with the progress of receptive field formation.

  16. Static quantities of the W bosons in the MSSM

    CERN Document Server

    Lahanas, Athanasios B

    1995-01-01

    I discuss the static quantities of the W boson, magnetic dipole and electric quadrupole moments, in the context of the minimal supersymmetric standard model, in which supersymmetry is broken by soft terms A_o,\\, m_o,\\, M_{1/2}. Following a renormalization group analysis it is found that the supersymmetric values of \\Delta k_{\\gamma} and \\Delta Q_{\\gamma} can be largely different, in some cases, from the standard model predictions but of the same order of magnitude for values of \\quad A_0,m_0,M_{1/2} \\leq {\\cal O}(1 TeV) . Therefore possible supersymmetric structure can be probed provided the accuracy of measurements for \\Delta k_{\\gamma}, \\Delta Q_{\\gamma} reaches 10^{-2}-10^{-3} and hence hard to be detected at LEP2. In cases where M_{1/2} \\ll A_0,m_0 , the charginos and neutralinos may give substantial contributions saturating the LEP2 sensitivity limits. This occurs when their masses m_{\\tilde C},m_{\\tilde Z} turn out to be both light satisfying m_{\\tilde C}+m_{\\tilde Z} \\simeq M_W . However these extreme ...

  17. Biokinetics and dosimetric studies about {sup 99m}Tc(V)DMSA distribution

    Energy Technology Data Exchange (ETDEWEB)

    Correia, M.B.L.; Magnata, S.S.L.P.; Silva, I.M.S.; Lima, F.F.; Catanho, M.T.J.A., E-mail: marilialiborio@ig.com.br, E-mail: sfmagnata@terra.com.br, E-mail: isvania@gmail.com, E-mail: fima@cnen.gov.br, E-mail: mariajansem@terra.com.br [Centro Regional de Ciencias Nucleares (CRCN/CNEN-PE), Recife, PE (Brazil)

    2008-07-01

    Research for radiodiagnostic agents should considerate biological critical parameters as half-life effective, target/not target uptake ratio and metabolites that together will determinate the biokinetic. Each parameter give own contribution in the absorbed dose. The dimercaptosuccinic acid (DMSA) labeled with {sup 99m}Tc(VN) is a radiopharmaceutical which has well established role in medullar thyroid carcinoma and has been proposed in complementary evaluation of bone metastasis. The aim of this work was study the biokinetics and dosimetry of {sup 99m}Tc(V)-DMSA by animal model. The {sup 99m}Tc(V)-DMSA was prepared by (III)DMSA kit alkalized. The methodology used mice, 70 days old, both males and females. The animals (n=5) received {sup 99m}Tc(V)DMSA administered IV (tail vein). After determinate times (30 min, 1h, 5h and 12h) the animals were sacrificed, the organs (blood, lungs, kidneys, muscle and bone) were excised and the activities were measured by a gamma counter. The results were evaluated based on %activity/g and the absorbed dose was estimated by extrapolation of data from animal to human, using the residence time to each organ in the MIRDOSE 3.0 program. The results show that the majority of organs reaches the top uptake at 30 min, the kidney has the greatest uptake in this time, (4.81 ± 1.38) % activity per gram, while the bone presents its highest uptake at 1h (5.49 ± 0.47)% activity per gram, after 1h all the organs had activity exponential decrease. About the absorbed dose estimated to human scale, the preliminary results showed higher value to bone, being the soft tissue dose relatively low. These dose values, however, are submitted to biological implications which are under studying yet. The biokinetic profile of {sup 99m}Tc(V)-DMSA, prepared from a DMSA kit by IPEN, was well established, allowing quantifying of residence time, while the dosimetric model presented preliminary data which directs to new analyzes.

  18. Dosimetric characterization and organ dose assessment in digital breast tomosynthesis: Measurements and Monte Carlo simulations using voxel phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Mariana, E-mail: marianabaptista@ctn.ist.utl.pt; Di Maria, Salvatore; Barros, Sílvia; Vaz, Pedro [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela LRS 2695-066 (Portugal); Figueira, Catarina [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University, Belfast BT7 1NN (United Kingdom); Sarmento, Marta; Orvalho, Lurdes [Serviço de Imagiologia, Hospital da Luz, Avenida Lusíada, 100, Lisboa 1500-650 (Portugal)

    2015-07-15

    Purpose: Due to its capability to more accurately detect deep lesions inside the breast by removing the effect of overlying anatomy, digital breast tomosynthesis (DBT) has the potential to replace the standard mammography technique in clinical screening exams. However, the European Guidelines for DBT dosimetry are still a work in progress and there are little data available on organ doses other than to the breast. It is, therefore, of great importance to assess the dosimetric performance of DBT with respect to the one obtained with standard digital mammography (DM) systems. The aim of this work is twofold: (i) to study the dosimetric properties of a combined DBT/DM system (MAMMOMAT Inspiration Siemens{sup ®}) for a tungsten/rhodium (W/Rh) anode/filter combination and (ii) to evaluate organs doses during a DBT examination. Methods: For the first task, measurements were performed in manual and automatic exposure control (AEC) modes, using two homogeneous breast phantoms: a PMMA slab phantom and a 4 cm thick breast-shaped rigid phantom, with 50% of glandular tissue in its composition. Monte Carlo (MC) simulations were performed using Monte Carlo N-Particle eXtended v.2.7.0. A MC model was implemented to mimic DM and DBT acquisitions for a wide range of x-ray spectra (24 –34 kV). This was used to calculate mean glandular dose (MGD) and to compute series of backscatter factors (BSFs) that could be inserted into the DBT dosimetric formalism proposed by Dance et al. Regarding the second aim of the study, the implemented MC model of the clinical equipment, together with a female voxel phantom (“Laura”), was used to calculate organ doses considering a typical DBT acquisition. Results were compared with a standard two-view mammography craniocaudal (CC) acquisition. Results: Considering the AEC mode, the acquisition of a single CC view results in a MGD ranging from 0.53 ± 0.07 mGy to 2.41 ± 0.31 mGy in DM mode and from 0.77 ± 0.11 mGy to 2.28 ± 0.32 mGy in DBT mode

  19. Needle migration and dosimetric impact in high-dose-rate brachytherapy for prostate cancer evaluated by repeated MRI.

    Science.gov (United States)

    Buus, Simon; Lizondo, Maria; Hokland, Steffen; Rylander, Susanne; Pedersen, Erik M; Tanderup, Kari; Bentzen, Lise

    2017-09-18

    To quantify needle migration and dosimetric impact in high-dose-rate brachytherapy for prostate cancer and propose a threshold for needle migration. Twenty-four high-risk prostate cancer patients treated with an HDR boost of 2 × 8.5 Gy were included. Patients received an MRI for planning (MRI1), before (MRI2), and after treatment (MRI3). Time from needle insertion to MRI3 was ∼3 hours. Needle migration was evaluated from coregistered images: MRI1-MRI2 and MRI1-MRI3. Dose volume histogram parameters from the treatment plan based on MRI1 were related to parameters based on needle positions in MRI2 or MRI3. Regression was used to model the average needle migration per implant and change in D90 clinical target volume, CTVprostate+3mm. The model fit was used for estimating the dosimetric impact in equivalent dose in 2 Gy fractions for dose levels of 6, 8.5, 10, 15, and 19 Gy. Needle migration was on average 2.2 ± 1.8 mm SD from MRI1-MRI2 and 5.0 ± 3.0 mm SD from MRI1-MRI3. D90 CTVprostate+3mm was robust toward average needle migration ≤3 mm, whereas for migration >3 mm D90 decreased by 4.5% per mm. A 3 mm of needle migration resulted in a decrease of 0.9, 1.7, 2.3, 4.8, and 7.6 equivalent dose in 2 Gy fractions for dose levels of 6, 8.5, 10, 15, and 19 Gy, respectively. Substantial needle migration in high-dose-rate brachytherapy occurs frequently in 1-3 hours following needle insertion. A 3-mm threshold of needle migration is proposed, but 2 mm may be considered for dose levels ≥15 Gy. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  20. The dosimetric impact of leaf interdigitation and leaf width on VMAT treatment planning in Pinnacle: comparing Pareto fronts.

    Science.gov (United States)

    van Kesteren, Z; Janssen, T M; Damen, E; van Vliet-Vroegindeweij, C

    2012-05-21

    To evaluate in an objective way the effect of leaf interdigitation and leaf width on volumetric modulated arc therapy plans in Pinnacle. Three multileaf collimators (MLCs) were modeled: two 10 mm leaf width MLCs, with and without interdigitating leafs, and a 5 mm leaf width MLC with interdigitating leafs. Three rectum patients and three prostate patients were used for the planning study. In order to compare treatment techniques in an objective way, a Pareto front comparison was carried out. 200 plans were generated in an automated way, per patient per MLC model, resulting in a total of 3600 plans. From these plans, Pareto-optimal plans were selected which were evaluated for various dosimetric variables. The capability of leaf interdigitation showed little dosimetric impact on the treatment plans, when comparing the 10 mm leaf width MLC with and without leaf interdigitation. When comparing the 10 mm leaf width MLC with the 5 mm leaf width MLC, both with interdigitating leafs, improvement in plan quality was observed. For both patient groups, the integral dose was reduced by 0.6 J for the thin MLC. For the prostate patients, the mean dose to the anal sphincter was reduced by 1.8 Gy and the conformity of the V(95%) was reduced by 0.02 using the thin MLC. The V(65%) of the rectum was reduced by 0.1% and the dose homogeneity with 1.5%. For rectum patients, the mean dose to the bowel was reduced by 1.4 Gy and the mean dose to the bladder with 0.8 Gy for the thin MLC. The conformity of the V(95%) was equivalent for the 10 and 5 mm leaf width MLCs for the rectum patients. We have objectively compared three types of MLCs in a planning study for prostate and rectum patients by analyzing Pareto-optimal plans which were generated in an automated way. Interdigitation of MLC leafs does not generate better plans using the SmartArc algorithm in Pinnacle. Changing the MLC leaf width from 10 to 5 mm generates better treatment plans although the clinical relevance remains

  1. Dosimetric property of mineral extracted from calamari and exposed to gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Zaragoza, E.; Roman-Lopez, J.; Cruz, L. Perez; Furetta, C. [Unidad de Irradiacion y Seguridad Radiologica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F (Mexico); Chiaravalle, E.; Mangiacotti, M.; Marchesani, G. [Centro di Referenza Nazionale per la Ricerca della Radioattivita nel Settore Zootecnico-Veterinario, Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Via Manfredonia 20, I-71121 Foggia (Italy)

    2013-07-03

    Dosimetric property of polymineral fraction, quartz mainly, obtained from calamari was investigated. The commercial calamari samples from China and Sud Africa were collected in the markets of Italy. All polymineral debris were extracted and isolated from the whole body of calamari. The surface of the polymineral samples was analyzed by using the Scanning Electron Microscopy (SEM) and their chemical composition was determined using Energy Dispersive Spectroscopy (EDS). The polymineral was exposed to gamma rays ({sup 60}Co) at different doses (0.5-80 Gy) to determine dosimetric property. Thermoluminescent (TL) glow curves showed two peaks centered at around 98-100 Degree-Sign C and 128-138 Degree-Sign C temperature range. The glow curves have been analyzed by using a deconvolution program. A linear dose response between 0.5 to 20 Gy was observed. The TL response of the samples as a function of the time storage, fading, presented a reduction of about 36-40 % at the end of 24 h. The reproducibility of the TL response after ten cycles of irradiation-readout showed an acceptable standard deviation in dosimetry. The polimineral fraction obtained from calamari shows an interesting dosimetric property and it may be useful for dosimetry in gamma radiation field.

  2. Dosimetric verification of gated delivery of electron beams using a 2D ion chamber array

    Directory of Open Access Journals (Sweden)

    S A Yoganathan

    2015-01-01

    Full Text Available The purpose of this study was to compare the dosimetric characteristics; such as beam output, symmetry and flatness between gated and non-gated electron beams. Dosimetric verification of gated delivery was carried for all electron beams available on Varian CL 2100CD medical linear accelerator. Measurements were conducted for three dose rates (100 MU/min, 300 MU/min and 600 MU/min and two respiratory motions (breathing period of 4s and 8s. Real-time position management (RPM system was used for the gated deliveries. Flatness and symmetry values were measured using Imatrixx 2D ion chamber array device and the beam output was measured using plane parallel ion chamber. These detector systems were placed over QUASAR motion platform which was programmed to simulate the respiratory motion of target. The dosimetric characteristics of gated deliveries were compared with non-gated deliveries. The flatness and symmetry of all the evaluated electron energies did not differ by more than 0.7 % with respect to corresponding non-gated deliveries. The beam output variation of gated electron beam was less than 0.6 % for all electron energies except for 16 MeV (1.4 %. Based on the results of this study, it can be concluded that Varian CL2100 CD is well suitable for gated delivery of non-dynamic electron beams.

  3. Dosimetric characteristics of novalis Tx system with high definition multileaf collimator.

    Science.gov (United States)

    Chang, Zheng; Wang, Zhiheng; Wu, Q Jackie; Yan, Hui; Bowsher, Jim; Zhang, Junan; Yin, Fang-Fang

    2008-10-01

    A new Novalis Tx system equipped with a high definition multileaf collimator (HDMLC) recently became available to perform both image-guided radiosurgery and conventional radiotherapy. It is capable of delivering a highly conformal radiation dose with three energy modes: 6 MV photon energy, 15 MV photon energy, and 6 MV photon energy in a stereotactic radiosurgery mode with 1000 MU/min dose rate. Dosimetric characteristics of the new Novalis Tx treatment unit with the HDMLC are systematically measured for commissioning. A high resolution diode detector and miniion-chamber detector are used to measure dosimetric data for a range of field sizes from 4 x 4 mm to 400 x 400 mm. The commissioned Novalis Tx system has passed the RPC stereotactic radiosurgery head phantom irradiation test. The Novalis Tx system not only expands its capabilities with three energy modes, but also achieves better beam conformity and sharer beam penumbra with HDMLC. Since there is little beam data information available for the new Novalis Tx system, we present in this work the dosimetric data of the new modality for reference and comparison.

  4. Dosimetric characteristics of Novalis Tx system with high definition multileaf collimator

    Energy Technology Data Exchange (ETDEWEB)

    Chang Zheng; Wang Zhiheng; Wu, Q. Jackie; Yan Hui; Bowsher, Jim; Zhang Junan; Yin Fangfang [Department of Radiation Oncology, Duke University, Box 3295, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2008-10-15

    A new Novalis Tx system equipped with a high definition multileaf collimator (HDMLC) recently became available to perform both image-guided radiosurgery and conventional radiotherapy. It is capable of delivering a highly conformal radiation dose with three energy modes: 6 MV photon energy, 15 MV photon energy, and 6 MV photon energy in a stereotactic radiosurgery mode with 1000 MU/min dose rate. Dosimetric characteristics of the new Novalis Tx treatment unit with the HDMLC are systematically measured for commissioning. A high resolution diode detector and miniion-chamber detector are used to measure dosimetric data for a range of field sizes from 4x4 mm to 400x400 mm. The commissioned Novalis Tx system has passed the RPC stereotactic radiosurgery head phantom irradiation test. The Novalis Tx system not only expands its capabilities with three energy modes, but also achieves better beam conformity and sharer beam penumbra with HDMLC. Since there is little beam data information available for the new Novalis Tx system, we present in this work the dosimetric data of the new modality for reference and comparison.

  5. The construction of conserved quantities for linearly coupled oscillators and study of symmetries about the conserved quantities

    Institute of Scientific and Technical Information of China (English)

    Lou Zhi-Mei

    2007-01-01

    In this paper, the conserved quantities are constructed using two methods. The first method is by making an ansatz of the conserved quantity and then using the definition of Poisson bracket to obtain the coefficients in the ansatz. The main procedure for the second method is given as follows. Firstly, the coupled terms in Lagrangian are eliminated by changing the coordinate scales and rotating the coordinate axes, secondly, the conserved quantities are obtain in new coordinate directly, and at last, the conserved quantities are expressed in the original coordinates by using the inverse transform of the coordinates. The Noether symmetry and Lie symmetry of the infinitesimal transformations about the conserved quantities are also studied in this paper.

  6. Forecasting the manpower demand for quantity surveyors in Hong Kong

    Directory of Open Access Journals (Sweden)

    Paul H K Ho

    2013-09-01

    Full Text Available Recently, there has been a massive infrastructure development and an increasing demand for public and private housing, resulting in a shortage of qualified quantity surveyors. This study aims to forecast the demand for qualified quantity surveyors in Hong Kong from 2013 to 2015. Literature review indicates that the demand for quantity surveyors is a function of the gross values of building, civil engineering and maintenance works. The proposed forecasting method consists of two steps. The first step is to estimate the gross values of building, civil engineering and maintenance works by time series methods and the second step is to forecast the manpower demand for quantity surveyors by causal methods. The data for quantity surveyors and construction outputs are based on the ‘manpower survey reports of the building and civil engineering industry’ and the ‘gross value of construction works performed by main contractors’ respectively. The forecasted manpower demand for quantity surveyors in 2013, 2014 and 2015 are 2,480, 2,632 and 2,804 respectively. Due to the low passing rate of the assessment of professional competence (APC and the increasing number of retired qualified members, there will be a serious shortage of qualified quantity surveyors in the coming three years.

  7. Forecasting the manpower demand for quantity surveyors in Hong Kong

    Directory of Open Access Journals (Sweden)

    Paul H K Ho

    2013-09-01

    Full Text Available Recently, there has been a massive infrastructure development and an increasing demand for public and private housing, resulting in a shortage of qualified quantity surveyors. This study aims to forecast the demand for qualified quantity surveyors in Hong Kong from 2013 to 2015. Literature review indicates that the demand for quantity surveyors is a function of the gross values of building, civil engineering and maintenance works. The proposed forecasting method consists of two steps. The first step is to estimate the gross values of building, civil engineering and maintenance works by time series methods and the second step is to forecast the manpower demand for quantity surveyors by causal methods. The data for quantity surveyors and construction outputs are based on the ‘manpower survey reports of the building and civil engineering industry’ and the ‘gross value of construction works performed by main contractors’ respectively. The forecasted manpower demand for quantity surveyors in 2013, 2014 and 2015 are 2,480, 2,632 and 2,804 respectively. Due to the low passing rate of the assessment of professional competence (APC and the increasing number of retired qualified members, there will be a serious shortage of qualified quantity surveyors in the coming three years.

  8. Impact of the Velo 2 half misalignment on physical quantities

    CERN Document Server

    Roguljic, Matej; Borghi, Silvia; Grillo, Lucia; CERN. Geneva. EP Department

    2016-01-01

    The impact of the misalignment of the Vertex Locator of the LHCb experiment on the physical quantities of the decay "$D^{*+} \\rightarrow (D^{0}\\rightarrow K^{-}\\pi^{+}) \\pi^{+} $" is studied in this note. Different misalignments of the 2 halves are applied to Monte Carlo data and the variations of the physical quantities with respect to the case without misalignment are evaluated. The results show the importance of the VELO 2 half alignment which can significantly affect the physics performance in the large misalignment case. A misalignment equal to the precision of the real-time alignment of the Vertex Locator is found to have a negligible effect on the studied physical quantities.

  9. OpenMath Content Dictionaries for SI Quantities and Units

    Science.gov (United States)

    2009-07-01

    mole, and candela , corresponding to the seven SI base quantities. There is a necessary one-to-one mapping between the base quantities and the base...kelvin, mole, and candela . The base units, with the inclusion of the unit named one, with symbol, 1, form an abelian generating set for the infinite...BaseUnits1 CD defines metre, kilogram, second, ampere, kelvin, mole, and candela . For completeness, in both the SI BaseQuantities1 and SI BaseUnits1 CDs

  10. Hojman Conserved Quantities for Birkhoffian Systems in Event Space

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi

    2008-01-01

    This paper focuses on studying a Hojman conserved quantity directly derived from a Lie symmetry for a Birkhoffian system in the event space.The Birkhoffian parametric equations for the system are established,and the determining equations of Lie symmetry for the system are obtained.The conditions under which a Lie symmetry of Birkhoffian system in the event space can directly lead up to a Hojman conserved quantity and the form of the Hojman conserved quantity are given.An example is given to illustrate the application of the results.

  11. Dosimetric comparison of helical tomotherapy and dynamic conformal arc therapy in stereotactic radiosurgery for vestibular schwannomas.

    Science.gov (United States)

    Lee, Tsair-Fwu; Chao, Pei-Ju; Wang, Chang-Yu; Lan, Jen-Hong; Huang, Yu-Je; Hsu, Hsuan-Chih; Sung, Chieh-Cheng; Su, Te-Jen; Lian, Shi-Long; Fang, Fu-Min

    2011-01-01

    The dosimetric results of stereotactic radiosurgery (SRS) for vestibular schwannoma (VS) performed using dynamic conformal arc therapy (DCAT) with the Novalis system and helical TomoTherapy (HT) were compared using plan quality indices. The HT plans were created for 10 consecutive patients with VS previously treated with SRS using the Novalis system. The dosimetric indices used to compare the techniques included the conformity index (CI) and homogeneity index (HI) for the planned target volume (PTV), the comprehensive quality index (CQI) for nine organs at risk (OARs), gradient score index (GSI) for the dose drop-off outside the PTV, and plan quality index (PQI), which was verified using the plan quality discerning power (PQDP) to incorporate 3 plan indices, to evaluate the rival plans. The PTV ranged from 0.27-19.99 cm(3) (median 3.39 cm(3)), with minimum required PTV prescribed doses of 10-16 Gy (median 12 Gy). Both systems satisfied the minimum required PTV prescription doses. HT conformed better to the PTV (CI: 1.51 ± 0.23 vs. 1.94 ± 0.34; p < 0.01), but had a worse drop-off outside the PTV (GSI: 40.3 ± 10.9 vs. 64.9 ± 13.6; p < 0.01) compared with DCAT. No significant difference in PTV homogeneity was observed (HI: 1.08 ± 0.03 vs. 1.09 ± 0.02; p = 0.20). HT had a significantly lower maximum dose in 4 OARs and significant lower mean dose in 1 OAR; by contrast, DCAT had a significantly lower maximum dose in 1 OAR and significant lower mean dose in 2 OARs, with the CQI of the 9 OARs = 0.92 ± 0.45. Plan analysis using PQI (HT 0.37 ± 0.12 vs. DCAT 0.65 ± 0.08; p < 0.01), and verified using the PQDP, confirmed the dosimetric advantage of HT. However, the HT system had a longer beam-on time (33.2 ± 7.4 vs. 4.6 ± 0.9 min; p < 0.01) and consumed more monitor units (16772 ± 3803 vs. 1776 ± 356.3; p < 0.01). HT had a better dose conformity and similar dose homogeneity but worse dose gradient than DCAT. Plan analysis confirmed the dosimetric advantage of HT

  12. Spatial variation of dosimetric leaf gap and its impact on dose delivery

    Energy Technology Data Exchange (ETDEWEB)

    Kumaraswamy, Lalith K., E-mail: Lalith.Kumaraswamy@roswellpark.org [Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 and Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Schmitt, Jonathan D. [Department of Radiation Medicine, RadAmerica, LLC-MedStar Health, Baltimore, Maryland 21237 (United States); Bailey, Daniel W. [Department of Radiation Oncology, Northside Hospital, Atlanta, Georgia 30342 (United States); Xu, Zheng Zheng [Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14260 (United States); Podgorsak, Matthew B. [Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14260 (United States)

    2014-11-01

    Purpose: During dose calculation, the Eclipse treatment planning system (TPS) retracts the multileaf collimator (MLC) leaf positions by half of the dosimetric leaf gap (DLG) value (measured at central axis) for all leaf positions in a dynamic MLC plan to accurately model the rounded leaf ends. The aim of this study is to map the variation of DLG along the travel path of each MLC leaf pair and quantify how this variation impacts delivered dose. Methods: 6 MV DLG values were measured for all MLC leaf pairs in increments of 1.0 cm (from the line intersecting the CAX and perpendicular to MLC motion) to 13.0 cm off axis distance at dmax. The measurements were performed on two Varian linear accelerators, both employing the Millennium 120-leaf MLCs. The measurements were performed at several locations in the beam with both a Sun Nuclear MapCHECK device and a PTW pinpoint ion chamber. Results: The measured DLGs for the middle 40 MLC leaf pairs (each 0.5 cm width) at positions along a line through the CAX and perpendicular to MLC leaf travel direction were very similar, varying maximally by only 0.2 mm. The outer 20 MLC leaf pairs (each 1.0 cm width) have much lower DLG values, about 0.3–0.5 mm lower than the central MLC leaf pair, at their respective central line position. Overall, the mean and the maximum variation between the 0.5 cm width leaves and the 1.0 cm width leaf pairs are 0.32 and 0.65 mm, respectively. Conclusions: The spatial variation in DLG is caused by the variation of intraleaf transmission through MLC leaves. Fluences centered on the CAX would not be affected since DLG does not vary; but any fluences residing significantly off axis with narrow sweeping leaves may exhibit significant dose differences. This is due to the fact that there are differences in DLG between the true DLG exhibited by the 1.0 cm width outer leaves and the constant DLG value utilized by the TPS for dose calculation. Since there are large differences in DLG between the 0.5 cm width

  13. Radioembolisation with {sup 90}Y-microspheres: dosimetric and radiobiological investigation for multi-cycle treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cremonesi, Marta; Ferrari, Mahila; Pedroli, Guido [European Institute of Oncology, Unit of Medical Physics, Milan (Italy); Bartolomei, Mirco; Arico, Demetrio; De Cicco, Concetta [European Institute of Oncology, Division of Nuclear Medicine, Milan (Italy); Orsi, Franco; Bonomo, Guido [European Institute of Oncology, Unit of Interventistic Radiology, Milan (Italy); Mallia, Andrew [Gamma Unit, Radiology Department, St. Luke' s Hospital (Malta); Paganelli, Giovanni [European Institute of Oncology, Division of Nuclear Medicine, Milan (Italy)

    2008-11-15

    Radioembolisation with {sup 90}Y-microspheres is a new locoregional treatment of hepatic lesions, usually applied as single cycle. Multi-cycle treatments might be considered as a strategy to improve the risk-benefit balance. With the aim to derive suitable information for patient tailored therapy, available patients' dosimetric data were reviewed according to the linear-quadratic model and converted into biological effective dose (BED) values. Single vs. multi-cycle approaches were compared through radiobiological perspective. Twenty patients with metastatic lesions underwent radioembolisation. The {sup 90}Y-administered activity (AA) was established in order to respect a precautionary limit dose (40 Gy) for the non-tumoral liver (NTL). BED was calculated setting {alpha}/{beta} = 2.5 Gy (NTL), 10 Gy (tumours); T{sub 1/2,eff} = T{sub 1/2,phys} = 64.2 h; T{sub 1/2,rep} = 2.5 h (NTL), 1.5 h (tumours). The BED to NTL was considered as a constraint for multi-cycle approach. The AA for two cycles and the percent variations of AA, tumour dose, BED were estimated. In one-cycle, for a prescribed BED to NTL of 64 Gy (NTL dose = 40 Gy), AA was 1.7 (0.9-3.2) GBq, tumour dose was 130 (65-235) Gy, and tumour BED was 170 (75-360) Gy. Considering two cycles, {proportional_to}15% increase was found for AA and dose to NTL, with unvaried BED for NTL. Tumour dose increase was 20 (10-35) Gy; tumour BED increase was 10 (3-11) Gy. In different protocols allowing 80 Gy to NTL, the BED sparing estimated was {proportional_to}50 Gy (two cycles) and 65 Gy (three cycles). From a radiobiological perspective, multi-cycle treatments would allow administering higher activities with increased tumour irradiation and preserved radiation effects on NTL. Trials comparing single vs. multiple cycles are suggested. (orig.)

  14. Improvement in DTPA efficacy for plutonium decorporation: biokinetic and dosimetric approaches

    Energy Technology Data Exchange (ETDEWEB)

    Serandour, A.L.; Grillon, G.; Taulelle, C.; Frechou, M.; Ben Salah, M.; Fritsch, P.; Le Gall, B.; Poncy, J.L. [CEA Bruyeres-le-Chatel (DSV/DRR), Lab. Radiotoxicologie, 91 (France); Gervelas, C.; Tsapis, N.; Fatal, E. [Paris-11 Univ., UMR CNRS 8612, Physico-chimie-Pharmacotechnie-Biopharmacie, 92 - Chatenay-Malabry (France); Phan, G.; Benech, H. [CEA Saclay (DSV/DRM), Service de Pharmacologie et d' Immunologie, 91 - Gif-sur-Yvette (France); Deverre, J.R. [Service Hospitalier Frederic Joliot (CEA/DSV/DRM), 91 - Gif-sur-Yvette (France)

    2006-07-01

    amount of Pu in blood and STO. By contrast, a good was obtained after application of the new systemic model reported by Leggett et al[7]. The best fit was obtained by adding the hypothesis that, during the first 1 days following the contamination, 30% of Pu retained in a liver compartment liverO, was de-corporated, whereas, this value was only 3 % later on. As concerned the modeling of the behavior of Pu-DTPA, 3 compartments were considered (DTPAo (60 %, fraction daily excreted (Ia) 10 d{sup -1}) DTPA, (36 %, is 0.2 d{sup -1}) a DTPA2 (4 %, I 10.02 d{sup -1}). Moreover, 90 % of Pu in DTPAo and DTPA, can de-corporated after each DTPA treatment. Some experimental data suggest that the DTPA compartments are located within the kidneys. Dose calculation shows that the treatments reduced by a factor of 3 the systemic effective dose. Thus, the dosimetric approach is useful, both to justify a DTPA treatment and to optimize administration schedule on the basis of a reduction of doses. Validation of the modeling assumptions is needed. For this purpose new experiments will performed in rodents and non human primates by using different chemical forms of actinides, after various modes of contamination. Moreover, different galenic forms of DTPA will be administered. In conclusion, the combination of biokinetic and dosimetric approaches will provide a better knowledge in the mechanisms involved in DTPA decorporation of actinides which should be very useful to improve the management of accidental contamination in workers. Such an approach can only be performed by collaborative work involving pharmacology, radiobiology, radio-toxicology and radioprotection. (author)

  15. The Quality vs. the Quantity of Schooling: What Drives Economic Growth?

    Science.gov (United States)

    Breton, Theodore R.

    2011-01-01

    This paper challenges Hanushek and Woessmann's (2008) contention that the quality and not the quantity of schooling determines a nation's rate of economic growth. I first show that their statistical analysis is flawed. I then show that when a nation's average test scores and average schooling attainment are included in a national income model,…

  16. Effect of Changes in Sleep Quantity and Quality on Depressive Symptoms among Korean Children

    Science.gov (United States)

    Lee, Joo Eun; Park, Sohee; Nam, Jin-Young; Ju, Young Jun; Park, Eun-Cheol

    2017-01-01

    This study aims to determine whether changes in sleep quantity and quality in childhood are associated with incidence of depressive symptoms. We used the three waves of the Korean Children & Youth Panel Survey (2011-2013). Statistical analysis using a generalized estimating equation model was performed. The 2,605 subjects analyzed included…

  17. The Quality vs. the Quantity of Schooling: What Drives Economic Growth?

    Science.gov (United States)

    Breton, Theodore R.

    2011-01-01

    This paper challenges Hanushek and Woessmann's (2008) contention that the quality and not the quantity of schooling determines a nation's rate of economic growth. I first show that their statistical analysis is flawed. I then show that when a nation's average test scores and average schooling attainment are included in a national income model,…

  18. FASH and MASH: female and male adult human phantoms based on polygon mesh surfaces: II. Dosimetric calculations

    Science.gov (United States)

    Kramer, R.; Cassola, V. F.; Khoury, H. J.; Vieira, J. W.; de Melo Lima, V. J.; Robson Brown, K.

    2010-01-01

    Female and male adult human phantoms, called FASH (Female Adult meSH) and MASH (Male Adult meSH), have been developed in the first part of this study using 3D animation software and anatomical atlases to replace the image-based FAX06 and the MAX06 voxel phantoms. 3D modelling methods allow for phantom development independent from medical images of patients, volunteers or cadavers. The second part of this study investigates the dosimetric implications for organ and tissue equivalent doses due to the anatomical differences between the new and the old phantoms. These differences are mainly caused by the supine position of human bodies during scanning in order to acquire digital images for voxel phantom development. Compared to an upright standing person, in image-based voxel phantoms organs are often coronally shifted towards the head and sometimes the sagittal diameter of the trunk is reduced by a gravitational change of the fat distribution. In addition, volumes of adipose and muscle tissue shielding internal organs are sometimes too small, because adaptation of organ volumes to ICRP-based organ masses often occurs at the expense of general soft tissues, such as adipose, muscle or unspecified soft tissue. These effects have dosimetric consequences, especially for partial body exposure, such as in x-ray diagnosis, but also for whole body external exposure and for internal exposure. Using the EGSnrc Monte Carlo code, internal and external exposure to photons and electrons has been simulated with both pairs of phantoms. The results show differences between organ and tissue equivalent doses for the upright standing FASH/MASH and the image-based supine FAX06/MAX06 phantoms of up to 80% for external exposure and up to 100% for internal exposure. Similar differences were found for external exposure between FASH/MASH and REGINA/REX, the reference voxel phantoms of the International Commission on Radiological Protection. Comparison of effective doses for external photon

  19. FASH and MASH: female and male adult human phantoms based on polygon mesh surfaces: II. Dosimetric calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, R; Cassola, V F; Khoury, H J [Department of Nuclear Energy, Federal University of Pernambuco, Avenida Prof. Luiz Freire, 1000, CEP 50740-540, Recife (Brazil); Vieira, J W [Federal Institute of Education, Science and Technology of Pernambuco, Recife (Brazil); De Melo Lima, V J [Department of Anatomy, Federal University of Pernambuco, Recife (Brazil); Robson Brown, K [Imaging Laboratory, Department of Archaeology and Anthropology, University of Bristol, Bristol (United Kingdom)], E-mail: rkramer@uol.com.br

    2010-01-07

    Female and male adult human phantoms, called FASH (Female Adult meSH) and MASH (Male Adult meSH), have been developed in the first part of this study using 3D animation software and anatomical atlases to replace the image-based FAX06 and the MAX06 voxel phantoms. 3D modelling methods allow for phantom development independent from medical images of patients, volunteers or cadavers. The second part of this study investigates the dosimetric implications for organ and tissue equivalent doses due to the anatomical differences between the new and the old phantoms. These differences are mainly caused by the supine position of human bodies during scanning in order to acquire digital images for voxel phantom development. Compared to an upright standing person, in image-based voxel phantoms organs are often coronally shifted towards the head and sometimes the sagittal diameter of the trunk is reduced by a gravitational change of the fat distribution. In addition, volumes of adipose and muscle tissue shielding internal organs are sometimes too small, because adaptation of organ volumes to ICRP-based organ masses often occurs at the expense of general soft tissues, such as adipose, muscle or unspecified soft tissue. These effects have dosimetric consequences, especially for partial body exposure, such as in x-ray diagnosis, but also for whole body external exposure and for internal exposure. Using the EGSnrc Monte Carlo code, internal and external exposure to photons and electrons has been simulated with both pairs of phantoms. The results show differences between organ and tissue equivalent doses for the upright standing FASH/MASH and the image-based supine FAX06/MAX06 phantoms of up to 80% for external exposure and up to 100% for internal exposure. Similar differences were found for external exposure between FASH/MASH and REGINA/REX, the reference voxel phantoms of the International Commission on Radiological Protection. Comparison of effective doses for external photon

  20. Potential benefits of dosimetric VMAT tracking verified with 3D film measurements

    Energy Technology Data Exchange (ETDEWEB)

    Crijns, Wouter, E-mail: wouter.crijns@uzleuven.be; Depuydt, Tom; Haustermans, Karin [Laboratory of Experimental Radiotherapy, KU Leuven Department of Oncology, Herestraat 49, 3000 Leuven (Belgium); Radiation Oncology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium); Defraene, Gilles [Laboratory of Experimental Radiotherapy, KU Leuven Department of Oncology, Herestraat 49, 3000 Leuven, Belgium and KU Leuven Medical Imaging Research Center, Herestraat 49, 3000 Leuven (Belgium); Van Herck, Hans [KU Leuven Medical Imaging Research Center, Herestraat 49, 3000 Leuven, Belgium and KU Leuven Department of Electrical Engineering (ESAT)–PSI, Center for Processing Speech and Images, 3000 Leuven (Belgium); Maes, Frederik [KU Leuven Medical Imaging Research Center, Herestraat 49, 3000 Leuven (Belgium); KU Leuven Department of Electrical Engineering (ESAT)–PSI, Center for Processing Speech and Images, 3000 Leuven (Belgium); Medical IT Department, KU Leuven iMinds, 3000 Leuven (Belgium); Van den Heuvel, Frank [Department of Oncology, MRC-CR-UK Gray Institute of Radiation Oncology and Biology, University of Oxford, Oxford OX1 2JD (United Kingdom)

    2016-05-15

    Purpose: To evaluate three different plan adaptation strategies using 3D film-stack dose measurements of both focal boost and hypofractionated prostate VMAT treatments. The adaptation strategies (a couch shift, geometric tracking, and dosimetric tracking) were applied for three realistic intrafraction prostate motions. Methods: A focal boost (35 × 2.2 and 35 × 2.7 Gy) and a hypofractionated (5 × 7.25 Gy) prostate VMAT plan were created for a heterogeneous phantom that allows for internal prostate motion. For these plans geometric tracking and dosimetric tracking were evaluated by ionization chamber (IC) point dose measurements (zero-D) and measurements using a stack of EBT3 films (3D). The geometric tracking applied translations, rotations, and scaling of the MLC aperture in response to realistic prostate motions. The dosimetric tracking additionally corrected the monitor units to resolve variations due to difference in depth, tissue heterogeneity, and MLC-aperture. The tracking was based on the positions of four fiducial points only. The film measurements were compared to the gold standard (i.e., IC measurements) and the planned dose distribution. Additionally, the 3D measurements were converted to dose volume histograms, tumor control probability, and normal tissue complication probability parameters (DVH/TCP/NTCP) as a direct estimate of clinical relevance of the proposed tracking. Results: Compared to the planned dose distribution, measurements without prostate motion and tracking showed already a reduced homogeneity of the dose distribution. Adding prostate motion further blurs the DVHs for all treatment approaches. The clinical practice (no tracking) delivered the dose distribution inside the PTV but off target (CTV), resulting in boost dose errors up to 10%. The geometric and dosimetric tracking corrected the dose distribution’s position. Moreover, the dosimetric tracking could achieve the planned boost DVH, but not the DVH of the more homogeneously

  1. Dosimetric measurements of an n-butyl cyanoacrylate embolization material for arteriovenous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Labby, Zacariah E., E-mail: zelabby@humonc.wisc.edu [Department of Human Oncology, University of Wisconsin–Madison, 600 Highland Avenue, Madison, Wisconsin 53792 (United States); Chaudhary, Neeraj [Division of Neurointerventional Radiology, Departments of Radiology and Neurosurgery, University of Michigan Hospital and Health Systems, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109 (United States); Gemmete, Joseph J. [Division of Neurointerventional Radiology, Departments of Radiology, Neurosurgery, and Otolaryngology, University of Michigan Hospital and Health Systems, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109 (United States); Pandey, Aditya S. [Department of Neurosurgery, University of Michigan Hospital and Health Systems, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109 (United States); Roberts, Donald A. [Radiation Physics Division, Department of Radiation Oncology, University of Michigan Hospital and Health Systems, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109 (United States)

    2015-04-15

    Purpose: The therapeutic regimen for cranial arteriovenous malformations often involves both stereotactic radiosurgery and endovascular embolization. Embolization agents may contain tantalum or other contrast agents to assist the neurointerventionalists, leading to concerns regarding the dosimetric effects of these agents. This study investigated dosimetric properties of n-butyl cyanoacrylate (n-BCA) plus lipiodol with and without tantalum powder. Methods: The embolization agents were provided cured from the manufacturer with and without added tantalum. Attenuation measurements were made for the samples and compared to the attenuation of a solid water substitute using a 6 MV photon beam. Effective linear attenuation coefficients (ELAC) were derived from attenuation measurements made using a portal imager and derived sample thickness maps projected in an identical geometry. Probable dosimetric errors for calculations in which the embolized regions are overridden with the properties of water were calculated using the ELAC values. Interface effects were investigated using a parallel plate ion chamber placed at set distances below fixed samples. Finally, Hounsfield units (HU) were measured using a stereotactic radiosurgery CT protocol, and more appropriate HU values were derived from the ELAC results and the CT scanner’s HU calibration curve. Results: The ELAC was 0.0516 ± 0.0063 cm{sup −1} and 0.0580 ± 0.0091 cm{sup −1} for n-BCA without and with tantalum, respectively, compared to 0.0487 ± 0.0009 cm{sup −1} for the water substitute. Dose calculations with the embolized region set to be water equivalent in the treatment planning system would result in errors of −0.29% and −0.93% per cm thickness of n-BCA without and with tantalum, respectively. Interface effects compared to water were small in magnitude and limited in distance for both embolization materials. CT values at 120 kVp were 2082 and 2358 HU for n-BCA without and with tantalum, respectively

  2. Energy taxes, resource taxes and quantity rationing for climate protection

    Energy Technology Data Exchange (ETDEWEB)

    Eisenack, Klaus [Oldenburg Univ. (Germany). Dept. of Economics; Edenhofer, Ottmar; Kalkuhl, Matthias [Potsdam-Institut fuer Klimafolgenforschung e.V., Potsdam (Germany)

    2010-11-15

    Economic sectors react strategically to climate policy, aiming at a re-distribution of rents. Established analysis suggests a Pigouvian emission tax as efficient instrument, but also recommends factor input or output taxes under specific conditions. However, existing studies leave it open whether output taxes, input taxes or input rationing perform better, and at best only touch their distributional consequences. When emissions correspond to extracted ressources, it is questionable whether taxes are effective at all. We determine the effectiveness, efficiency and functional income distribution for these instruments in the energy and resource sector, based on a game theoretic growth model with explicit factor markets and policy instruments. Market equilibrium depends on a government that acts as a Stackelberg leader with a climate protection goal. We find that resource taxes and cumulative resource quantity rationing achieve this objective efficiently. Energy taxation is only second best. Mitigation generates a substantial ''climate rent'' in the resource sector that can be converted to transfer incomes by taxes. (orig.)

  3. Comment on the Hojman conservation quantities in Cosmology

    CERN Document Server

    Paliathanasis, A

    2015-01-01

    We comment upon the application of Hojman's method for the determination of conservation laws in Cosmology, which has been introduced by Capozziello \\& Roshan (Phys. Lett. B 726 (2013) 471 (arXiv:1308.3910)), and has been applied recently in the cosmological scenario of a nonminimally coupled scalar field by Paolella \\& Capozziello (Phys. Lett. A (2015), in press (arXiv:1503.00098)). We apply the Ansatz, $\\phi\\left( t\\right) =\\phi\\left( a\\left( t\\right) \\right) $, which was introduced by the cited authors for a minimally-coupled scalar field, and we study the Lie and Noether point symmetries for the reduced equation. We show that under this Ansatz the unknown function of the model cannot be constrained by the requirement of the existence of a conservation law and that the Hojman conservation quantity which arises for the reduced equation is nothing more than the functional form of the Noether conservation law of momentum for the free particle. Finally we show that Hojman's method for Hamiltonian syste...

  4. Hyperspectral remote sensing of tropical grass quality and quantity

    NARCIS (Netherlands)

    Mutanga, O.

    2004-01-01

    Resource distribution is a fundamental factor governing the movement and distribution of herbivores. Specifically, the quality (foliar concentration of nitrogen, phosphorous, calcium, magnesium, potassium and sodium) and quantity (biomass) of vegetation are important factors. In this regard, the dev

  5. Partial enthalpies and related quantities in mixtures from computer simulation

    NARCIS (Netherlands)

    Sindzingre, P.; Ciccotti, G.; Massobrio, C.; Frenkel, D.

    1987-01-01

    We report a method of calculating partial molar quantities in mixtures by computer simulation. The method is based on an extension of Widom's potential distribution theorem and provides an alternative way of computing partial enthalpies and volumes.

  6. Assessment of petrophysical quantities inspired by joint multifractal approach

    CERN Document Server

    Lai, Z Koohi; Jafari, G R

    2015-01-01

    In this paper joint multifractal random walk approach is carried out to analyze some petrophysical quantities for characterizing the petroleum reservoir. These quantities include Gamma emission (GR), sonic transient time (DT) and Neutron porosity (NPHI) which are collected from four wells of a reservoir. To quantify mutual interaction of petrophysical quantities, joint multifractal random walk is implemented. This approach is based on the mutual multiplicative cascade notion in the multifractal formalism and in this approach $L_0$ represents a benchmark to describe the nature of cross-correlation between two series. The analysis of the petrophysical quantities revealed that GR for all wells has strongly multifractal nature due to the considerable abundance of large fluctuations in various scales. The variance of probability distribution function, $\\lambda_{\\ell}^2$, at scale $\\ell$ and its intercept determine the multifractal properties of the data sets sourced by probability density function. The value of $\\...

  7. Securing water quality and quantity: Research and development perspective

    CSIR Research Space (South Africa)

    Pienaar, H

    2012-10-01

    Full Text Available and quantity: Research and development perspective 4th Biennial Conference Harrison Pienaar 10 October 2012 Presentation outline ? Introduction and background to water in South Africa ? Transboundary water resource aspects ? Water related challenges...

  8. 49 CFR 173.306 - Limited quantities of compressed gases.

    Science.gov (United States)

    2010-10-01

    ... charged with compressed air or limited quantities of nitrogen to not over 40 psig for single-trip shipment... and part 177 except § 177.817. (1) The tank must be of steel, welded with heads concave to pressure...

  9. An adjusted energy-saving quantity calculation method for building energy-efficient retrofit

    Institute of Scientific and Technical Information of China (English)

    王清勤; 孟冲

    2009-01-01

    Aiming at a comprehensive assessment of energy-saving retrofitting effect on existing buildings,a calculation method is developed to adjust energy-saving quantity in standard condition for comparison under the same conditions. A mathematical model,method theory and calculation steps are given. Error analysis results show that this method can be applied accurately to practical engineering projects. In a case study of energy-saving quantity assessment before and after retrofitting on a certain hospital in Shanghai,with energy simulation software TRNSYS,detailed application of this method is introduced and analyzed. The method is applied to the case of energy-saving quantity assessment to a hospital in Shanghai before and after retrofitting with the energy simulation software TRNSYS.

  10. Noether conserved quantities and Lie point symmetries of difference Lagrange-Maxwell equations and lattices

    Institute of Scientific and Technical Information of China (English)

    Fu Jing-Li; Nie Ning-Ming; Huang Jian-Fei; Jiménez Salvador; Tang Yi-Fa; Vázquez Luis; Zhao Wei-Jia

    2009-01-01

    This paper presents a method to find Noether-type conserved quantities and Lie point symmetries for discrete mechanico-electrical dynamical systems, which leave invariant the set of solutions of the corresponding difference scheme.This approach makes it possible to devise techniques for solving the Lagrange-Maxwell equations in differences which correspond to mechanico-electrical systems, by adapting existing differential equations. In particular, it obtains a new systematic method to determine both the one-parameter Lie groups and the discrete Noether conserved quantities of Lie point symmetries for mechanico-electrical systems. As an application, it obtains the Lie point symmetries and the conserved quantities for the difference equation of a model that represents a capacitor microphone.

  11. Lie symmetries and conserved quantities of discrete nonholonomic Hamiltonian systems

    Institute of Scientific and Technical Information of China (English)

    Wang Xing-Zhong; Fu Hao; Fu Jing-Li

    2012-01-01

    This paper focuses on studying Lie symmetries and conserved quantities of discrete nonholonomic Hamiltonian systems.Firstly,the discrete generalized Hamiltonian canonical equations and discrete energy equation of nonholonomic Hamiltonian systems are derived from discrete Hamiltonian action.Secondly,the determining equations and structure equation of Lie symmetry of the system are obtained.Thirdly,the Lie theorems and the conservation quantities are given for the discrete nonholonomic Hamiltonian systems.Finally,an example is discussed to illustrate the application of the results.

  12. The qualitative advantages of quantities of information: bigger is better

    Institute of Scientific and Technical Information of China (English)

    LESK Michael

    2005-01-01

    Digitization projects should focus on quantity rather than quality. Increasing quantities of information produce qualitatively more valuable services. Online writing and searching are now common, and it is only online reading that is still limiting our use of online books. New interfaces might increase our willingness to read online, which should be encouraged rather than fought, since it represents an increase both the amount of information available and the participation of more people in the writing and exchange of information.

  13. Charaterisation of function spaces via mollification; fractal quantities for distributions

    Directory of Open Access Journals (Sweden)

    Hans Triebel

    2003-01-01

    Full Text Available The aim of this paper is twofold. First we characterise elements f belonging to the Besov spaces Bpqs(ℝn with s∈ℝ,  0quantities for distributions generalising well-known corresponding quantities for Radon measures.

  14. China Limits the Mining Quantity of Tungsten and Rare Earth

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>Based on a notice issued by the Ministry of Land Resources, China’s tungsten mining quantity in 2006 will be controlled to 59,060 tons in concentrates form, which include 4,250 tons of recycled tungsten. And the rare earth mining quantity in 2006 will also be controlled to 86,620 tons (REO) including 8,320 tons of heavy rare earth and 78,200 tons of light rare earth.

  15. The Research of Cost Control Model Based on the Quantity Discount under Supply Chain Finance%基于供应链金融的数量折扣成本控制模型研究——基于存货质押融资模式

    Institute of Scientific and Technical Information of China (English)

    李丽君; 吴晓会; 闫伟超

    2012-01-01

    基于供应链金融这一新型融资模式,研究信息不对称条件下供应链整体成本控制模型.以一条由单个核心制造商和存在资金约束的单个中小零售商组成的二级供应链为研究对象,在供应链金融模式下设计数量折扣成本控制模型,研究其对供应链整体成本和利润的影响.研究结果表明,该模型充分考虑了供应链物流、信息流和资金流的特点,在利用供应链金融缓解供应链资金失衡问题的同时,运用数量折扣对供应链企业的生产决策进一步协调,从而对供应链成本起到了良好的控制效果.最后通过实例研究验证了该模型的效果和可操作性.%Based on the supply chain finance,a new financing mode, and in the condition of information asymmetry, there has no research on the whole supply chain cost control. For the study,this paper took the secondary supply chain with a single manufacturer and a single small and medium-sized retailer existing core capital as the research object, designed the supply chain quantity discount cost control model under the supply chain finance,and gave the research of the supply chain cost and the influence of the profits. Research results showed that the model fully considered the supply chain logistics,information flow and cash flow characteristics,in the use of supply chain financial ease supply chain funds the imbalances,at the same time,used of the supply chain enterprise quantity discount to coordinate production decision further, so as to supply chain cost has excellent control effect. Finally the case study validated the feasibility of the mechanism.

  16. Principle of limitation of physical quantities and cyclic universe

    Institute of Scientific and Technical Information of China (English)

    HE GuoZhu

    2008-01-01

    A close study of Heisenberg uncertainty principles reveals many significant facts, and all four major physical quantities, energy, time, momentum and length, have both lower and upper limits. Now, many questions come up. What are these limits? Some answers may lead to the understanding of the development of our universe. What is the shortest limit of time? At the beginning of big bang, there exists a tre-mendously short time, the Planck time. This may be just the shortest time limit in our universe. The longest time limit might be the lifetime of our universe. The longest length might be the final diameter of our expanding universe. All these lead to a finite universe. Two more coupling formulae are formed for the other two pairs of physical quantities, mass and speed, thermal energy and temperature. These four physical quantities must also have limits. We already knew that speed has upper limit and temperature has lower limit. By these two formulae, Planck and Einstein equations are derived directly. Since most other physical quantities are somewhat related to these major physical quantities, it seems that there exists a principle of limitation of physical quantities. A quantitative sketch of big bang is described. It also shows that our universe will contract back to another big bang. The principle of limitation opens up some fields of investigation. It may bring nature back to the harmony and determined world described by classical physics.

  17. Development of Digital Computation of Building and Civil Engineering Quantities

    Directory of Open Access Journals (Sweden)

    Aderinola, O.S

    2014-06-01

    Full Text Available The work of Building and Civil engineering demands a greater knowledge, skill and precision in quantity estimation.The manual method of estimating quantities for building and civil engineering works has posed potential problem areas on work that is undertaken. The low reliability of manual estimation indicates discrepancies in the accuracy of quantities computed manually,hence,the introduction of a digital computation.It is envisaged that this method will greatly reduce the complexities of different aspects when computing quantities for projects, as well as reduce the time to complete the computation and therefore projects can be started earlier.The paper reviewed the procedures involved in the development of a computer program for the digital computation of Building and Civil engineering quantities.The program was developed using Microsoft Visual C SHARP (C# programming language and Microsoft Visual studio. The steps/procedure used in achieving the development of the computer program was (1.designing the application interface,(2 adding controls to the window and (3writing codes behind the interface.The digital computation was tested using a proposed Road project and a proposed administrative buildingand the results showed an average of 100% of the items has 0 to 10 percentage difference for the road and 92% for the building in the final outputs of the quantities obtained through the manual computation and the digital computation and the software could therefore be said to be accurate and reliable.

  18. Dosimetric effects of multileaf collimator leaf width on intensity-modulated radiotherapy for head and neck cancer.

    Science.gov (United States)

    Hong, Chae-Seon; Ju, Sang Gyu; Kim, Minkyu; Kim, Jung-In; Kim, Jin Man; Suh, Tae-Suk; Han, Youngyih; Ahn, Yong Chan; Choi, Doo Ho; Nam, Heerim; Park, Hee Chul

    2014-02-01

    The authors evaluated the effects of multileaf collimator (MLC) leaf width (2.5 vs. 5 mm) on dosimetric parameters and delivery efficiencies of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) for head and neck (H&N) cancers. The authors employed two types of mock phantoms: large-sized head and neck (LH&N) and small-sized C-shape (C-shape) phantoms. Step-and-shoot IMRT (S&S_IMRT) and VMAT treatment plans were designed with 2.5- and 5.0-mm MLC for both C-shape and LH&N phantoms. Their dosimetric characteristics were compared in terms of the conformity index (CI) and homogeneity index (HI) for the planning target volume (PTV), the dose to organs at risk (OARs), and the dose-spillage volume. To analyze the effects of the field and arc numbers, 9-field IMRT (9F-IMRT) and 13-field IMRT (13F-IMRT) plans were established for S&S_IMRT. For VMAT, single arc (VMAT1) and double arc (VMAT2) plans were established. For all plans, dosimetric verification was performed using the phantom to examine the relationship between dosimetric errors and the two leaf widths. Delivery efficiency of the two MLCs was compared in terms of beam delivery times, monitor units (MUs) per fraction, and the number of segments for each plan. 2.5-mm MLC showed better dosimetric characteristics in S&S_IMRT and VMAT for C-shape, providing better CI for PTV and lower spinal cord dose and high and intermediate dose-spillage volume as compared with the 5-mm MLC (p 0.05). Further, beam delivery efficiency was not observed to be significantly associated with leaf width for either C-shape or LH&N. However, MUs per fraction were significantly reduced for the 2.5-mm MLC for the LH&N. In dosimetric error analysis, absolute dose evaluations had errors of less than 3%, while the Gamma passing rate was greater than 95% according to the 3%/3 mm criteria. There were no significant differences in dosimetric error between the 2.5- and 5-mm MLCs. As compared with MLC of 5-mm leaf

  19. A predictive method of calculating the dosimetric effect of 1-D motion on narrow multileaf collimated segments.

    Science.gov (United States)

    Kelly, A; Williams, M; Metcalfe, P

    2009-03-01

    This study aims to investigate the utility of 1-D convolution as a predictive method to quantify the effect of patient movement as a result of respiration on segmented dose distributions typically found in IMRT. This is for the restricted case of 1-D motion perpendicular to the beam direction. A modified respiratory motion phantom was coupled to a solid water phantom and used to measure the dose distribution of several narrow MLC segments. The measured data was compared to dose distribution calculated by the mathematical convolution of static profiles with a probability distribution function (PDF) generated for sinusoidal motion and power cosine motion. The MLC segments for an IMRT field were also studied. Additionally, the dosimetric effect of intra-fraction patient motion combined with that of inter-fraction setup error, modelled using a Gaussian PDF, was calculated. Set-up variation and respiratory motion can significantly degrade the dose distribution of narrow segments. Our results emphasise the need to maintain the smallest feasible amplitude of respiratory motion and minimise set-up uncertainties, particularly when narrow segments are used.

  20. TU-CD-BRB-01: Normal Lung CT Texture Features Improve Predictive Models for Radiation Pneumonitis

    Energy Technology Data Exchange (ETDEWEB)

    Krafft, S [The University of Texas MD Anderson Cancer Center, Houston, TX (United States); The University of Texas Graduate School of Biomedical Sciences, Houston, TX (United States); Briere, T; Court, L; Martel, M [The University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: Existing normal tissue complication probability (NTCP) models for radiation pneumonitis (RP) traditionally rely on dosimetric and clinical data but are limited in terms of performance and generalizability. Extraction of pre-treatment image features provides a potential new category of data that can improve NTCP models for RP. We consider quantitative measures of total lung CT intensity and texture in a framework for prediction of RP. Methods: Available clinical and dosimetric data was collected for 198 NSCLC patients treated with definitive radiotherapy. Intensity- and texture-based image features were extracted from the T50 phase of the 4D-CT acquired for treatment planning. A total of 3888 features (15 clinical, 175 dosimetric, and 3698 image features) were gathered and considered candidate predictors for modeling of RP grade≥3. A baseline logistic regression model with mean lung dose (MLD) was first considered. Additionally, a least absolute shrinkage and selection operator (LASSO) logistic regression was applied to the set of clinical and dosimetric features, and subsequently to the full set of clinical, dosimetric, and image features. Model performance was assessed by comparing area under the curve (AUC). Results: A simple logistic fit of MLD was an inadequate model of the data (AUC∼0.5). Including clinical and dosimetric parameters within the framework of the LASSO resulted in improved performance (AUC=0.648). Analysis of the full cohort of clinical, dosimetric, and image features provided further and significant improvement in model performance (AUC=0.727). Conclusions: To achieve significant gains in predictive modeling of RP, new categories of data should be considered in addition to clinical and dosimetric features. We have successfully incorporated CT image features into a framework for modeling RP and have demonstrated improved predictive performance. Validation and further investigation of CT image features in the context of RP NTCP

  1. The behaviour of physical quantities in thin films near the Curie point

    Science.gov (United States)

    Korneta, W.; Pytel, Z.

    1982-05-01

    The Valenta model of a thin ferromagnetic film in the critical region above the Curie point has been considered. Spatial and temperature dependence for spin correlation time and magnetic susceptibility has been obtained and discussed. The results have been generalized and expressions describing the behaviour of any physical quantity in more complicated models of a thin ferromagnetic film near the Curie temperature have been given.

  2. Static Hedging with Uncertain Quantity and Departure from the Cost-of-Carry Valuation

    Institute of Scientific and Technical Information of China (English)

    Qing-wei Liu; Yi Li; Shou-yang Wang

    2006-01-01

    In this paper, we are concerned with the optimal hedge ratio under quantity risk as well as discrepancies between the futures market price and its theoretical valuation according to the cost-of-carry model.Assuming a geometric Brownian motion for forecasting process, we model mispricing as a specific noise component in the dynamics of futures market prices, based on which the optimal hedging strategy is calculated.Finally, we illustrate optimal strategy and its properties by numerical examples.

  3. Applicability of an exposure model for the determination of emissions from mobile phone base stations

    DEFF Research Database (Denmark)

    Breckenkamp, J; Neitzke, H P; Bornkessel, C

    2008-01-01

    Applicability of a model to estimate radiofrequency electromagnetic field (RF-EMF) strength in households from mobile phone base stations was evaluated with technical data of mobile phone base stations available from the German Net Agency, and dosimetric measurements, performed...

  4. Trained Quantity Abilities in Horses (Equus caballus: A Preliminary Investigation

    Directory of Open Access Journals (Sweden)

    Maria Elena Miletto Petrazzini

    2014-07-01

    Full Text Available Once believed to be a human prerogative, the capacity to discriminate between quantities now has also been reported in several vertebrates. To date, only two studies investigated numerical abilities in horses (Equus caballus but reported contrasting data. To assess whether horses can be trained to discriminate between quantities, I have set up a new experimental protocol using operant conditioning. One adult female was trained to discriminate between 1 and 4 (Test 1 in three different conditions: non-controlled continuous variables (numerical and continuous quantities that co-vary with number are simultaneously available, 50% controlled continuous variables (intermediate condition, and 100% controlled continuous variables (only numerical information available. The subject learned the discrimination in all conditions, showing the capacity to process numerical information. When presented with a higher numerical ratio (2 vs. 4, Test 2, the subject still discriminated between the quantities but its performance was statistically significant only in the non-controlled condition, suggesting that the subject used multiple cues in presence of a more difficult discrimination. On the whole, the results here reported encourage the use of this experimental protocol as a valid tool to investigate the capacity to process numerical and continuous quantities in horses in future research.

  5. Processing ordinality and quantity: the case of developmental dyscalculia.

    Science.gov (United States)

    Rubinsten, Orly; Sury, Dana

    2011-01-01

    In contrast to quantity processing, up to date, the nature of ordinality has received little attention from researchers despite the fact that both quantity and ordinality are embodied in numerical information. Here we ask if there are two separate core systems that lie at the foundations of numerical cognition: (1) the traditionally and well accepted numerical magnitude system but also (2) core system for representing ordinal information. We report two novel experiments of ordinal processing that explored the relation between ordinal and numerical information processing in typically developing adults and adults with developmental dyscalculia (DD). Participants made "ordered" or "non-ordered" judgments about 3 groups of dots (non-symbolic numerical stimuli; in Experiment 1) and 3 numbers (symbolic task: Experiment 2). In contrast to previous findings and arguments about quantity deficit in DD participants, when quantity and ordinality are dissociated (as in the current tasks), DD participants exhibited a normal ratio effect in the non-symbolic ordinal task. They did not show, however, the ordinality effect. Ordinality effect in DD appeared only when area and density were randomized, but only in the descending direction. In the symbolic task, the ordinality effect was modulated by ratio and direction in both groups. These findings suggest that there might be two separate cognitive representations of ordinal and quantity information and that linguistic knowledge may facilitate estimation of ordinal information.

  6. Processing ordinality and quantity: the case of developmental dyscalculia.

    Directory of Open Access Journals (Sweden)

    Orly Rubinsten

    Full Text Available In contrast to quantity processing, up to date, the nature of ordinality has received little attention from researchers despite the fact that both quantity and ordinality are embodied in numerical information. Here we ask if there are two separate core systems that lie at the foundations of numerical cognition: (1 the traditionally and well accepted numerical magnitude system but also (2 core system for representing ordinal information. We report two novel experiments of ordinal processing that explored the relation between ordinal and numerical information processing in typically developing adults and adults with developmental dyscalculia (DD. Participants made "ordered" or "non-ordered" judgments about 3 groups of dots (non-symbolic numerical stimuli; in Experiment 1 and 3 numbers (symbolic task: Experiment 2. In contrast to previous findings and arguments about quantity deficit in DD participants, when quantity and ordinality are dissociated (as in the current tasks, DD participants exhibited a normal ratio effect in the non-symbolic ordinal task. They did not show, however, the ordinality effect. Ordinality effect in DD appeared only when area and density were randomized, but only in the descending direction. In the symbolic task, the ordinality effect was modulated by ratio and direction in both groups. These findings suggest that there might be two separate cognitive representations of ordinal and quantity information and that linguistic knowledge may facilitate estimation of ordinal information.

  7. Large quantity discrimination by North Island robins (Petroica longipes).

    Science.gov (United States)

    Garland, Alexis; Low, Jason; Burns, Kevin C

    2012-11-01

    While numerosity-representation and enumeration of different numbers of objects-and quantity discrimination in particular have been studied in a wide range of species, very little is known about the numerical abilities of animals in the wild. This study examined spontaneous relative quantity judgments (RQJs) by wild North Island robins (Petroica longipes) of New Zealand. In Experiment 1, robins were tested on a range of numerical values of up to 14 versus 16 items, which were sequentially presented and hidden. In Experiment 2, the same numerical contrasts were tested on a different group of subjects but quantities were presented as whole visible sets. Experiment 3 involved whole visible sets that comprised of exceedingly large quantities of up to 56 versus 64 items. While robins shared with other species a ratio-based representation system for representing very large values, they also appeared to have developed an object indexing system with an extended upper limit (well beyond 4) that may be an evolutionary response to ecological challenges faced by scatter-hoarding birds. These results suggest that cognitive mechanism influencing an understanding of physical quantity may be deployed more flexibly in some contexts than previously thought, and are discussed in light of findings across other mammalian and avian species.

  8. Dosimetric optimization of a conical breast brachytherapy applicator for improved skin dose sparing

    Energy Technology Data Exchange (ETDEWEB)

    Yang Yun; Rivard, Mark J. [Biomedical Engineering and Biotechnology, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2010-11-15

    Purpose: Both the AccuBoost D-shaped and round applicators have been dosimetrically characterized and clinically used to treat patients with breast cancer. While the round applicators provide conformal dose coverage, under certain clinical circumstances the breast skin dose may be higher than preferred. The purpose of this study was to modify the round applicators to minimize skin dose while not substantially affecting dose uniformity within the target volume and reducing the treatment time. Methods: In order to irradiate the intended volume while sparing critical structures such as the skin, the current round applicator design has been augmented through the addition of an internal truncated cone (i.e., frustum) shield. Monte Carlo methods and clinical constraints were used to design the optimal cone applicator. With the cone applicator now defined as the entire assembly including the surrounding tungsten-alloy shell holding the HDR {sup 192}Ir source catheter, the applicator height was reduced to diminish the treatment time while minimizing skin dose. Monte Carlo simulation results were validated using both radiochromic film and ionization chamber measurements based on established techniques. Results: The optimal cone applicators diminished the maximum skin dose by 15%-32% (based on the applicator diameter and breast separation) with the tumor dose reduced by less than 3% for a constant exposure time. Furthermore, reduction in applicator height diminished the treatment time by up to 30%. Radiochromic film and ionization chamber dosimetric results in phantom agreed with Monte Carlo simulation results typically within 3%. Larger differences were outside the treatment volume in low dose regions or associated with differences between the measurement and Monte Carlo simulation environments. Conclusions: A new radiotherapy treatment device was developed and dosimetrically characterized. This set of applicators significantly reduces the skin dose and treatment time while

  9. Dosimetric Implications of Residual Tracking Errors During Robotic SBRT of Liver Metastases.

    Science.gov (United States)

    Chan, Mark; Grehn, Melanie; Cremers, Florian; Siebert, Frank-Andre; Wurster, Stefan; Huttenlocher, Stefan; Dunst, Jürgen; Hildebrandt, Guido; Schweikard, Achim; Rades, Dirk; Ernst, Floris; Blanck, Oliver

    2017-03-15

    Although the metric precision of robotic stereotactic body radiation therapy in the presence of breathing motion is widely known, we investigated the dosimetric implications of breathing phase-related residual tracking errors. In 24 patients (28 liver metastases) treated with the CyberKnife, we recorded the residual correlation, prediction, and rotational tracking errors from 90 fractions and binned them into 10 breathing phases. The average breathing phase errors were used to shift and rotate the clinical tumor volume (CTV) and planning target volume (PTV) for each phase to calculate a pseudo 4-dimensional error dose distribution for comparison with the original planned dose distribution. The median systematic directional correlation, prediction, and absolute aggregate rotation errors were 0.3 mm (range, 0.1-1.3 mm), 0.01 mm (range, 0.00-0.05 mm), and 1.5° (range, 0.4°-2.7°), respectively. Dosimetrically, 44%, 81%, and 92% of all voxels differed by less than 1%, 3%, and 5% of the planned local dose, respectively. The median coverage reduction for the PTV was 1.1% (range in coverage difference, -7.8% to +0.8%), significantly depending on correlation (P=.026) and rotational (P=.005) error. With a 3-mm PTV margin, the median coverage change for the CTV was 0.0% (range, -1.0% to +5.4%), not significantly depending on any investigated parameter. In 42% of patients, the 3-mm margin did not fully compensate for the residual tracking errors, resulting in a CTV coverage reduction of 0.1% to 1.0%. For liver tumors treated with robotic stereotactic body radiation therapy, a safety margin of 3 mm is not always sufficient to cover all residual tracking errors. Dosimetrically, this translates into only small CTV coverage reductions. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Dosimetric comparison of Helical Tomotherapy and Gamma Knife Stereotactic Radiosurgery for single brain metastasis

    Directory of Open Access Journals (Sweden)

    Linskey Mark E

    2006-08-01

    Full Text Available Abstract Background Helical Tomotherapy (HT integrates linear accelerator and computerized tomography (CT technology to deliver IMRT. Targets are localized (i.e. outlined as gross tumor volume [GTV] and planning target volume [PTV] on the planning kVCT study while daily MVCT is used for correction of patient's set-up and assessment of inter-fraction anatomy changes. Based on dosimetric comparisons, this study aims to find dosimetric equivalency between single fraction HT and Gamma Knife® stereotactic radiosurgery (GKSRS for the treatment of single brain metastasis. Methods The targeting MRI data set from the GKSRS were used for tomotherapy planning. Five patients with single brain metastasis treated with GKSRS were re-planned in the HT planning station using the same prescribed doses. There was no expansion of the GTV to create the PTV. Sub-volumes were created within the PTV and prescribed to the maximum dose seen in the GKSRS plans to imitate the hot spot normally seen in GKSRS. The PTV objective was set as a region at risk in HT planning using the same prescribed dose to the PTV periphery as seen in the corresponding GKSRS plan. The tumor volumes ranged from 437–1840 mm3. Results Conformality indices are inconsistent between HT and GKSRS. HT generally shows larger lower isodose line volumes, has longer treatment time than GKSRS and can treat a much larger lesion than GKSRS. Both HT and GKSRS single fraction dose-volume toxicity may be prohibitive in treating single or multiple lesions depending on the number and the sizes of the lesions. Conclusion Based on the trend for larger lower dose volumes and more constricted higher dose volumes in HT as compared to GKSRS, dosimetric equivalency was not reached between HT and GKSRS.

  11. Clinical Dosimetric Comparison among Different Intensity-Modulated Radiotherapy Plans for Nasopharyngeal Carcinoma

    Directory of Open Access Journals (Sweden)

    Changjiang Sun

    2014-03-01

    Full Text Available Objective: To compare the dosimetric differences of different intensity-modulated radiation therapy (IMRT plans for nasopharyngeal carcinoma (NPC. Methods: 5-, 7- and 9-fields of IMRT plans in 16 NPC patients were respectively designed and synchronous dimention technology was applied to compare the dosimetric differences in target areas and involved organs. Results: The recovery rate in target area was 95% while the plan was evidently worse in 5-field than in 7- and 9-fields (P < 0.05. Whereas the maximum dosage (Dmax, mean dosage (Dmean and minimum dosage (Dmin were similar between 7- and 9-fields (P > 0.05, which were obviously lower in 5-field, and the differences were both significant (P < 0.05. In addition, the conformity and homogeneity indexes in target area had no significant difference between 7- and 9-fields, but were markedly better than in 5-field (P < 0.05. Indexes in each involved organs were the lowest in 5-field than in other fields (P < 0.05, but were similar between 7- and 9-fields (P > 0.05, which were all lower than tolerant dosage. As for BODY, there were significant differences in V10 - V20 between 5-field and other fields (P < 0.05, but were similar in V25 - V30 (P > 0.05. However, 7- and 9-fields were similar in V10 - V20 (P > 0.05. Conclusion: 7-field IMRT plan is the optimal one for NPC on both clinical dosimetric requirements and field-establishment principles.

  12. SU-E-T-123: Dosimetric Comparison Between Portrait and Landscape Orientations in Radiochromic Film Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kakinohana, Y [University of the Ryukyus, Okinawa (Japan); Toita, T; Kasuya, G; Ariga, T; Heianna, J; Murayama, S [University of the Ryukyus, Nishihara-cho, Okinawa (Japan)

    2014-06-01

    Purpose: To compare the dosimetric properties of radiochromic films with different orientation. Methods: A sheet of EBT3 film was cut into eight pieces with the following sizes: 15×15 cm2 (one piece), 5x15 cm{sup 2} (two) and 4×5 cm{sup 2} (five). A set of two EBT3 sheets was used at each dose level. Two sets were used changing the delivered doses (1 and 2 Gy). The 5×15 cm{sup 2} pieces were rotated by 90 degrees in relation to each other, such that one had landscape orientation and the other had portrait orientation. All 5×15 cm2 pieces were irradiated with their long side aligned with the x-axis of the radiation field. The 15×15 cm{sup 2} pieces were irradiated rotated at 90 degrees to each other. Five pieces, (a total of ten from two sheets) were used to obtain a calibration curve. The irradiated films were scanned using an Epson ES-2200 scanner and were analyzed using ImageJ software. In this study, no correction was applied for the nonuniform scanner signal that is evident in the direction of the scanner lamp. Each film piece was scanned both in portrait and landscape orientations. Dosimetric comparisons of the beam profiles were made in terms of the film orientations (portrait and landscape) and scanner bed directions (perpendicular and parallel to the scanner movement). Results: In general, portrait orientation exhibited higher noise than landscape and was adversely affected to a great extent by the nonuniformity in the direction of the scanner lamp. A significant difference in the measured field widths between the perpendicular and parallel directions was found for both orientations. Conclusion: Without correction for the nonuniform scanner signal in the direction of the scanner lamp, a landscape orientation is preferable. A more detailed investigation is planned to evaluate quantitatively the effect of orientation on the dosimetric properties of a film.

  13. SU-E-CAMPUS-I-02: Estimation of the Dosimetric Error Caused by the Voxelization of Hybrid Computational Phantoms Using Triangle Mesh-Based Monte Carlo Transport

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C [Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD (United States); Badal, A [U.S. Food ' Drug Administration (CDRH/OSEL), Silver Spring, MD (United States)

    2014-06-15

    Purpose: Computational voxel phantom provides realistic anatomy but the voxel structure may result in dosimetric error compared to real anatomy composed of perfect surface. We analyzed the dosimetric error caused from the voxel structure in hybrid computational phantoms by comparing the voxel-based doses at different resolutions with triangle mesh-based doses. Methods: We incorporated the existing adult male UF/NCI hybrid phantom in mesh format into a Monte Carlo transport code, penMesh that supports triangle meshes. We calculated energy deposition to selected organs of interest for parallel photon beams with three mono energies (0.1, 1, and 10 MeV) in antero-posterior geometry. We also calculated organ energy deposition using three voxel phantoms with different voxel resolutions (1, 5, and 10 mm) using MCNPX2.7. Results: Comparison of organ energy deposition between the two methods showed that agreement overall improved for higher voxel resolution, but for many organs the differences were small. Difference in the energy deposition for 1 MeV, for example, decreased from 11.5% to 1.7% in muscle but only from 0.6% to 0.3% in liver as voxel resolution increased from 10 mm to 1 mm. The differences were smaller at higher energies. The number of photon histories processed per second in voxels were 6.4×10{sup 4}, 3.3×10{sup 4}, and 1.3×10{sup 4}, for 10, 5, and 1 mm resolutions at 10 MeV, respectively, while meshes ran at 4.0×10{sup 4} histories/sec. Conclusion: The combination of hybrid mesh phantom and penMesh was proved to be accurate and of similar speed compared to the voxel phantom and MCNPX. The lowest voxel resolution caused a maximum dosimetric error of 12.6% at 0.1 MeV and 6.8% at 10 MeV but the error was insignificant in some organs. We will apply the tool to calculate dose to very thin layer tissues (e.g., radiosensitive layer in gastro intestines) which cannot be modeled by voxel phantoms.

  14. A solution procedure for mixed-integer nonlinear programming formulation of supply chain planning with quantity discounts under demand uncertainty

    Science.gov (United States)

    Yin, Sisi; Nishi, Tatsushi

    2014-11-01

    Quantity discount policy is decision-making for trade-off prices between suppliers and manufacturers while production is changeable due to demand fluctuations in a real market. In this paper, quantity discount models which consider selection of contract suppliers, production quantity and inventory simultaneously are addressed. The supply chain planning problem with quantity discounts under demand uncertainty is formulated as a mixed-integer nonlinear programming problem (MINLP) with integral terms. We apply an outer-approximation method to solve MINLP problems. In order to improve the efficiency of the proposed method, the problem is reformulated as a stochastic model replacing the integral terms by using a normalisation technique. We present numerical examples to demonstrate the efficiency of the proposed method.

  15. Dosimetric analysis of SMD phototransistor in dental phantom of different geometries

    Energy Technology Data Exchange (ETDEWEB)

    Belinato, W.; Magalhaes, C. M. S.; Souza, D. N. [Departmento de Fisica, Universidade Federal de Sergipe, Av. Marechal Rondon s/n, 49.100-000, Rosa Elze, Sao Cristovao-SE (Brazil); Santos, L. A. P. [Laboratorio de Instrumentacao Nuclear, Centro Regional de Ciencias Nucleares, Av. Professor Luiz Freire, 200, 50-740-540, Recife-PE (Brazil)

    2009-10-15

    A commercial surface mount device (SMD) phototransistor, OP520, was inserted in two dental phantoms for dosimetric analysis. The irradiations were accomplished in a dental x-ray equipment of 80 kV using different exposition times. A standard ionization chamber was irradiated at the same conditions and the air kerma measured with it was compared with the electrical charge evaluated by the phototransistor. The results showed satisfactory correspondence among the detectors readings. Moreover, the phototransistor showed up quite sensitively for dental applications, allowing verifying the variations for the different phantoms configurations. (Author)

  16. Evaluation of dosimetric parameters of a commercial semiconductor device in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, C. M. S.; Sobrinho, M. C.; Souza, D. N. [Departmento de Fisica, Universidade Federale de Sergipe, Av. Marechal Rondon s/n, 49.100-000, Rosa Elze, Sao Cristovao-SE (Brazil); Santos, L. A. P. [Laboratorio de Instrumentacao Nuclear, Centro Regional de Ciencias Nucleares, Av. Professor Luiz Freire, 200, 50.740-540 Recife-PE (Brazil)

    2009-10-15

    Semiconductor devices have been widely used for dosimetry in radiotherapy and more recently in diagnostic radiology. In order to evaluate the performance of a phototransistor as a radiation detector in computed tomography (CT), some dosimetric parameters were evaluated, such as: repetitive, angular dependence, response for different tube potentials, dose and dose rate dependence. The irradiation was performed with the detector on the axis of rotation of a X-ray tube in CT scanner. The results showed that, making the necessary corrections, it is possible to use the phototransistor for dosimetry in tomography. (Author)

  17. Determination of dosimetric and kinetic features of gamma irradiated solid calcium ascorbate dihydrate using ESR spectroscopy

    Science.gov (United States)

    Tuner, H.

    2013-01-01

    Effects of gamma radiation on solid calcium ascorbate dihydrate were studied using electron spin resonance (ESR) spectroscopy. Irradiated samples were found to present two specific ESR lines with shoulder at low and high magnetic field sides. Structural and kinetic features of the radicalic species responsible for experimental ESR spectrum were explored through the variations of the signal intensities with applied microwave power, variable temperature, high-temperature annealing and room temperature storage time studies. Dosimetric potential of the sample was also determined using spectrum area and measured signal intensity measurements. It was concluded that three radicals with different spectroscopic and kinetic features were produced upon gamma irradiation.

  18. A dosimetric analysis of the aeroformTM tissue expander in radiation therapy

    Directory of Open Access Journals (Sweden)

    Tai Tran

    2014-08-01

    Full Text Available Purpose: The aim of this study is to evaluate the effects of the metallic reservoir and the use of gas within the Aeroform™ tissue expander with respect to the radiation dose distribution.Methods: Dosimetric effects of using a metallic reservoir within a breast tissue expander during external beam radiotherapy were investigated. To view the internal components of the reservoir, it was removed from the tissue expander and imaged on a Varian AS500 electronic portal imager. To calculate the relative density of each component within the reservoir, an ionization chamber within solid water was used to measure the dose and compared to a simulation within the Pinnacle treatment planning system (TPS. To examine the relative dose profile along the length of the reservoir, the reservoir was exposed on EBT3 film and analyzed using SNC Patient™. In-vivo Dosimetry was performed using a RANDO® Woman phantom. Thermo-luminescent dosimeters were placed within the wax bolus enveloping the tissue expander.Results: Imaging the reservoir on the electronic portal imager revealed it consists of 3 distinct components. The densities assigned in the TPS, which resulted in calculated doses which matched the measured doses were; Section 1 = 0 g/cm3, Section 2 = 2.8 g/cm3 and Section 3 = 0.7 g/cm3. Relative dose reductions were observed due to the metallic case; Section 1 = 20%, Section 2 = 40% and Section 3 = 30%. Entrance doses ranged from 2.39 - 2.53 Gy for both the medial and lateral beams. Exit doses ranging from 1.10 - 1.71 Gy were observed in both beams. There was a significant difference in measured and calculated doses at exit locations in the beam.Conclusion: Dosimetric effects due to the metallic reservoir within the Aeroform breast tissue expander have been demonstrated and have been observed to be significant. To increase the dosimetric accuracy when contouring, individual components of the reservoir should be distinguished. Our in-vivo experiment showed

  19. Dosimetric impact of a change in breathing period on VMAT stereotactic ablative body radiotherapy

    Science.gov (United States)

    Olding, T.; Alexander, KM

    2017-05-01

    The dosimetric impact of a change in breathing period during treatment was assessed for a volumetric modulated arc therapy (VMAT) stereotactic ablative radiotherapy (SABR) lung plan optimized according to our centre’s planning protocol. Plan delivery was evaluated at three breathing rates ranging from 7 to 23 breaths-per-minute (BPM) against the planning anatomy (15 BPM) calculated dose. Dynamic ion chamber, EBT3 film and Fricke-xylenol orange-gelatin (FXG) gel measurements were acquired using a motion phantom with appropriate inserts for each dosimeter. The results show good agreement between measured and calculated plan dose within the internal gross tumour volume (IGTV) target.

  20. Tin-117m-APDDMP for Osteosarcoma Treatment: Biodistribution and Dosimetric Considerations

    Energy Technology Data Exchange (ETDEWEB)

    Botelho, M.F.; Caramelo, F.; Gomes, C. [IBILI - Faculdade de Medicina de Coimbra, Azinhaga de Santa Comba, 3000-354 Coimbra (Portugal); Zeevaart, J.R.; Louw, W.K.A. [Radiochemistry, NECSA, PO Box 582, Pretoria 0001 (Saudi Arabia); Dormehl, I.C. [Institute for Life Sciences, University of Pretoria, Pretoria 0001 (Saudi Arabia); Kolar, Z.I.; Krijger, G.C. [Department of Radiochemistry, Delft University of Technology, Mekelveg 15, 2629 JB, Delft (Netherlands); Milner, R.J. [Department of Small Animal Clinical Sciences, University of Florida (United States)

    2006-05-15

    Physical characteristics of tin-117m (13.6 d half-life, conversion electrons) make it an excellent agent for primary or secondary bone cancer treatment. In this work we present the results obtained with a biphosphonate, APDDMP labeled with tin-117m, which is a bone seeking agent. The results obtained indicate that the proposed radiopharmaceutical presents some problems as bone seeking agent, because the biodistribution data demonstrate that kidney and bladder together with the urine have a noticeable uptake, which, in a dosimetric context, means that the bladder becomes the target organ, which is undesirable. (author)

  1. Comparison of dosimetric standards of USA and France for HDR brachytherapy

    Science.gov (United States)

    Douysset, Guilhem; Gouriou, Jean; Delaunay, Frank; DeWerd, Larry; Stump, Kurt; Micka, John

    2005-05-01

    A bilateral comparison of national dosimetric standards for high dose rate brachytherapy has been conducted between the Laboratoire National Henri Becquerel and the University of Wisconsin Accredited Dosimetry Calibration Laboratory. A complete overview of the methods that are currently in use to establish the two national standards is given. The comparison has been carried out using well-type transfer ionization chambers. Three units have been calibrated in both laboratories, and calibration coefficients have been compared. The discrepancies between the two measurements are within 0.3%.

  2. [Dosimetric characteristics of the bremsstrahlung beam from the LUE-15M medical linear electron accelerator].

    Science.gov (United States)

    Vatnitskiĭ, S M; Ermakov, I A; Puzanov, V P; Sinitsyn, R V; Cherviakov, A M

    1983-10-01

    The paper presents methods and results of a study of radiation-physical characteristics of inhibitory radiation beam with the Grenz energy of 15MeV generated by an electron linear accelerator LUE-15M. Special emphasis is laid on primary dosimetric information used for the planning of radiotherapy: depth doses, beam profiles, dose functions of a collimated beam. It has been shown that in general the accelerator meets the requirements of the International Electrotechnical Commission. General error in the focal absorbed dose at the expense of variable parameters of the accelerator was evaluated. It does not exceed +/- 3.5%.

  3. Energy absorption buildup factors for thermoluminescent dosimetric materials and their tissue equivalence

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2010-01-01

    -absorption buildup factor data have been studied as a function of penetration depth and incident photon energy. Buildup factors determined in the present work should be useful in radiation dosimetry, diagnostics and therapy. The tissue equivalence of TLD materials is also discussed.......Gamma ray energy-absorption buildup factors were computed using the five-parameter geometric progression (G-P) fitting formula for seven thermoluminescent dosimetric (TLD) materials in the energy range 0.015-15 MeV, and for penetration depths up to 40 mfp (mean free path). The generated energy...

  4. Dosimetric- and Geometric Evaluation of Adaptive H&N IMRT Using Deformable Image Registration

    DEFF Research Database (Denmark)

    Eiland, R.B.; Behrens, C. F.; Sjöström, D.

    2012-01-01

    Purpose/Objective: Anatomical changes can occur during RT treatment of H&N cancer patients. This can lead to a difference between planned- and delivered dose. Adaptive RT has the potential to overcome this, utilizing deformable image registration (DIR). The purpose of this study was to evaluate...... to the ReCT in four of seven patients with regard to the target. Larger geometrical variations were observed for organs at risk (OAR). OAR contours obtained with the DIR were for nearly all patients estimated smaller than in the ReCT whereas target contours were estimated larger. The dosimetric results...

  5. Harmonisation and dosimetric quality assurance in individual monitoring for external radiation

    DEFF Research Database (Denmark)

    Bartlett, D.T.; Ambrosi, P.; Back, C.

    2001-01-01

    The current situation amongst Member States is that there are widely differing national requirements for dosimetric services and for dosemeter performance. It is clear that with the free movement of workers within the European Union (EU) and the requirements for individual dosimetry given...... in Council Directive 96/29 EURATOM, a degree of harmonisation of requirements and procedures of EU Member States would be desirable. A EURADOS action group, made up of members from each of the EU Member States plus Switzerland, was set up with the overall objectives of consolidating within the EU the quality...

  6. Birthday Cake Activity Structured Arrangement for Helping Children Determining Quantities

    Directory of Open Access Journals (Sweden)

    Neni Mariana

    2010-07-01

    Full Text Available Few researches have been concerned about relation between children’s spatial thinking and number sense. Narrowing for this small research, we focused on one component of spatial thinking, that is structuring objects, and one component of number senses, that is cardinality by determining quantities. This study focused on a design research that was conducted in Indonesia in which we investigated pre-school children’s (between 2 and 3.5 years old ability in making structured arrangement and their ability to determine the quantities by looking at the arrangements. The result shows us that some of the children were able to make such arrangement. However, the children found difficulties either to determine quantities from those arrangements or to compare some structures to easily recognize number of objects.

  7. Pseudotensor applied to Numerical Relativity in Calculating Global Quantities

    CERN Document Server

    Tsai, Chung-Chin; Lin, Chun-Yu; Yo, Hwei-Jang

    2015-01-01

    In this work we apply the Landau-Lifshitz pseudotensor flux formalism to the calculation of the total mass and the total angular momentum during the evolution of a binary black hole system. We also compare its performance with the traditional integrations for the global quantities. It shows that the advantage of the pseudotensor flux formalism is the smoothness of the numerical value of the global quantities, especially of the total angular momentum. Although the convergence behavior of the global quantities with the pseudotensor flux method is only comparable with the ones with the traditional method, the smoothness of its numerical value allows using a larger radius for surface integration to obtain more accurate result.

  8. A shared system of representation governing quantity discrimination in canids

    Directory of Open Access Journals (Sweden)

    Joseph M Baker

    2012-10-01

    Full Text Available One way to investigate the evolution of cognition is to compare the abilities of phylogenetically related species. The domestic dog (Canis lupus familiaris, for example, still shares cognitive abilities with the coyote (C. latrans. Both of these canids possess the ability to make psychophysical less/more discriminations of food based on quantity. Like many other species including humans, this ability is mediated by Weber’s Law: discrimination of continuous quantities is dependent on the ratio between the two quantities. As two simultaneously presented quantities of food become more similar, choice of the large or small option becomes random in both dogs and coyotes. It remains unknown, however, whether these closely related species within the same family—one domesticated, and one wild—make such quantitative comparisons with comparable accuracy. Has domestication honed or diminished this quantitative ability? Might different selective and ecological pressures facing coyotes drive them to be more or less able to accurately represent and discriminate food quantity than domesticated dogs? This study is an effort to elucidate this question concerning the evolution of non-verbal quantitative cognition.Here, we tested the quantitative discrimination ability of 16 domesticated dogs. Each animal was given 9 trials in which two different quantities of food were simultaneously displayed to them. The domesticated dogs’ performance on this task was then compared directly to the data from 16 coyotes’ performance on this same task reported by Baker and colleagues (2011.The quantitative discrimination abilities between the two species were strikingly similar. Domesticated dogs demonstrated similar quantitative sensitivity as coyotes, suggesting that domestication may not have significantly altered the psychophysical discrimination abilities of canids. Instead, this study provides further evidence for similar nonverbal quantitative abilities across

  9. Principle of limitation of physical quantities and cyclic universe

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A close study of Heisenberg uncertainty principles reveals many significant facts,and all four major physical quantities,energy,time,momentum and length,have both lower and upper limits.Now,many questions come up.What are these limits?Some answers may lead to the understanding of the development of our universe.What is the shortest limit of time?At the beginning of big bang,there exists a tre-mendously short time,the Planck time.This may be just the shortest time limit in our universe.The longest time limit might be the lifetime of our universe.The longest length might be the final diameter of our expanding universe.All these lead to a finite universe.Two more coupling formulae are formed for the other two pairs of physical quantities,mass and speed,thermal energy and temperature.These four physical quantities must also have limits.We already knew that speed has upper limit and temperature has lower limit.By these two formulae,Planck and Einstein equations are derived directly.Since most other physical quantities are somewhat related to these major physical quantities,it seems that there exists a principle of limitation of physical quantities.A quantitative sketch of big bang is described.It also shows that our universe will contract back to another big bang.The principle of limitation opens up some fields of investigation.It may bring nature back to the harmony and determined world described by classical physics.

  10. Difference in quantity discrimination in dogs and wolves

    Directory of Open Access Journals (Sweden)

    Friederike eRange

    2014-11-01

    Full Text Available Certain aspects of social life, such as engaging in intergroup conflicts, as well as challenges posed by the physical environment, may facilitate the evolution of quantity discrimination. In lack of excessive comparative data, one can only hypothesize about its evolutionary origins, but human-raised wolves performed well when they had to choose the larger of two sets of 1 to 4 food items that had been sequentially placed into two opaque cans. Since in such paradigms, the animals never see the entire content of either can, their decisions are thought to rely on mental representation of the two quantities rather than on some perceptual factors such as the overall volume or surface area of the two amounts. By equaling the time that it takes to enter each quantity into the cans or the number of items entered, one can further rule out the possibility that animals simply choose based on the amount of time needed to present the two quantities. While the wolves performed well even in such a control condition, dogs failed to choose the larger one of two invisible quantities in another study using a similar paradigm. Because this disparity could be explained by procedural differences, in the current study, we set out to test dogs that were raised and kept identically as the previously tested wolves using the same set-up and procedure. Our results confirm the former finding that dogs, in comparison to wolves, have inferior skills to represent quantities mentally. This seems to be in line with a Frank's (1980 hypothesis suggesting that domestication altered the information processing of dogs. However, as discussed, also alternative explanations may exist.

  11. A Characterization of Conserved Quantities in Non-Equilibrium Thermodynamics

    Directory of Open Access Journals (Sweden)

    Ignacio Romero

    2013-12-01

    Full Text Available The well-known Noether theorem in Lagrangian and Hamiltonian mechanics associates symmetries in the evolution equations of a mechanical system with conserved quantities. In this work, we extend this classical idea to problems of non-equilibrium thermodynamics formulated within the GENERIC (General Equations for Non-Equilibrium Reversible-Irreversible Coupling framework. The geometric meaning of symmetry is reviewed in this formal setting and then utilized to identify possible conserved quantities and the conditions that guarantee their strict conservation. Examples are provided that demonstrate the validity of the proposed definition in the context of finite and infinite dimensional thermoelastic problems.

  12. Manual of symbols and terminology for physicochemical quantities and units

    CERN Document Server

    Whiffen, D H

    2013-01-01

    Manual of Symbols and Terminology for Physicochemical Quantities and Units, 1979 Edition contains physical quantity tabulations of products. The Commission on Symbols, Terminology, and Units is a part of the Division of Physical Chemistry of the International Union of Pure and Applied Chemistry. Its general responsibilities are to secure clarity and precision, and wider agreement in the use of symbols, by chemists in different countries, among physicists, chemists, and engineers, and by editors of scientific journals. This book is composed of 13 chapters, and begins with the determination o

  13. Covariant Hamiltonian boundary term: Reference and quasi-local quantities

    CERN Document Server

    Sun, Gang; Liu, Jian-Liang; Nester, James M

    2016-01-01

    The Hamiltonian for dynamic geometry generates the evolution of a spatial region along a vector field. It includes a boundary term which determines both the value of the Hamiltonian and the boundary conditions. The value gives the quasi-local quantities: energy-momentum, angular-momentum and center-of-mass. The boundary term depends not only on the dynamical variables but also on their reference values; the latter determine the ground state (having vanishing quasi-local quantities). For our preferred boundary term for Einstein's GR we propose 4D isometric matching and extremizing the energy to determine the reference metric and connection values.

  14. Conformal Invariance and Conserved Quantities of General Holonomic Systems

    Institute of Scientific and Technical Information of China (English)

    CAI Jian-Le

    2008-01-01

    Conformal invarianee and conserved quantities of general holonomic systems are studied. A one-parameter infinitesimal transformation group and its infinitesimal transformation vector of generators are described.The definition of conformal invariance and determining equation for the system are provided.The conformal factor expression is deduced from conformal invariance and Lie symmetry.The necessary and sufficient condition,that conformal invariance of the system would be Lie symmetry,is obtained under the infinitesimal one-parameter transformation group. The corresponding conserved quantity is derived with the aid of a structure equation.Lastly,an example is given to demonstrate the application of the result.

  15. SYMMETRIES AND CONSERVED QUANTITIES FOR SYSTEMS OF GENERALIZED CLASSICAL MECHANICS

    Institute of Scientific and Technical Information of China (English)

    Zhang Yi; Shang Mei; Mei Feng-xiang

    2000-01-01

    In this paper, the symmetries and the conserved quantities for systemsof generalized classical mechanics are studied. First, the generalizedNoether's theorem and the generalized Noether's inverse theorem of thesystems are given, which are based upon the invariant properties of thecanonical action with respect to the action of the infinitesimaltransformation of r-parameter finite group of transformation; second,the Lie symmetries and conserved quantities of the systems are studiedin accordance with the Lie's theory of the invariance of differentialequations under the transformation of infinitesimal groups; and finally,the inner connection between the two kinds of symmetries of systems isdiscussed.

  16. Core skills requirement and competencies expected of quantity surveyors: perspectives from quantity surveyors, allied professionals and clients in Nigeria

    Directory of Open Access Journals (Sweden)

    Joshua Oluwasuji Dada

    2015-10-01

    Full Text Available Abstract Deployment of appropriate skills and competencies is crucial and germane to the development and continuous relevance of any profession. In the built environment, the science for selecting the required skills and competencies expected of quantity surveyors and understanding the inherent dependencies between them remains a research issue. The purpose of this study was to determine the skill requirements and competencies expected of quantity surveyors. A structured questionnaire was administered among quantity surveyors, architects, engineers, builders and clients in Nigeria. The respondents were asked to give rating, on a 5 point Likert scale, on usual skills and competencies required of quantity surveyors. A secondary objective of the study was to examine the important skills and competencies and categorized them into core skill, basic skill, core competence, optional competence and special competence. The results of the study indicate the important skills as computer literacy, building engineering, information technology, economics, measurement/quantification and knowledge of civil/heavy engineering works. The results also indicate the important competencies as cost planning and control, estimating, construction procurement system, contract documentation, contract administration and project management. It is emphasized that the findings of the research have considerable implications on the training and practice of quantity surveying in Nigeria.

  17. Core skills requirement and competencies expected of quantity surveyors: perspectives from quantity surveyors, allied professionals and clients in Nigeria

    Directory of Open Access Journals (Sweden)

    Joshua Oluwasuji Dada

    2012-12-01

    Full Text Available AbstractDeployment of appropriate skills and competencies is crucial and germane to the development and continuous relevance of any profession. In the built environment, the science for selecting the required skills and competencies expected of quantity surveyors and understanding the inherent dependencies between them remains a research issue. The purpose of this study was to determine the skill requirements and competencies expected of quantity surveyors. A structured questionnaire was administered among quantity surveyors, architects, engineers, builders and clients in Nigeria. The respondents were asked to give rating, on a 5 point Likert scale, on usual skills and competencies required of quantity surveyors. A secondary objective of the study was to examine the important skills and competencies and categorized them into core skill, basic skill, core competence, optional competence and special competence. The results of the study indicate the important skills as computer literacy, building engineering, information technology, economics, measurement/quantification and knowledge of civil/heavy engineering works. The results also indicate the important competencies as cost planning and control, estimating, construction procurement system, contract documentation, contract administration and project management. It is emphasized that the findings of the research have considerable implications on the training and practice of quantity surveying in Nigeria.

  18. An experimental palladium-103 seed (OptiSeed{sup exp}) in a biocompatible polymer without a gold marker: Characterization of dosimetric parameters including the interseed effect

    Energy Technology Data Exchange (ETDEWEB)

    Abboud, F.; Scalliet, P.; Vynckier, S. [Cliniques Universitaires Saint-Luc, Radiotherapy and Oncology Department, Catholic University of Louvain, Brussels 1020 (Belgium)

    2008-12-15

    Permanent implantation of {sup 125}I (iodine) or {sup 103}Pd (palladium) sources is a popular treatment option in the management of early stage prostate cancer. New sources are being developed, some of which are being marketed for different clinical applications. A new technique of adjuvant stereotactic permanent seed breast implant, similar to that used in the treatment of prostate cancer, has been proposed by [N. Jansen et al., Int. J. Radiat. Oncol. Biol. Phys. 67, 1052-1058 (2007)] with encouraging results. The presence of artifacts from the metallic seeds, however, can disturb follow-up imaging. The development of plastic seeds has reduced these artifacts. This paper presents a feasibility study of the advantages of palladium-103 seeds, encapsulated with a biocompatible polymer, for future clinical applications, and on the effect of the gold marker on the dosimetric characteristics of such seeds. Experimental palladium seeds, OptiSeed{sup exp}, were manufactured by International Brachytherapy (IBt), Seneffe, Belgium, from a biocompatible polymer, including the marker. Apart from the absence of a gold marker, the studied seed has an identical design to the OptiSeed{sup 103}[Phys. Med. Biol. 50, 1493-1504 (2005)]; [Appl. Radiat. Isot. 63, 311-321 (2005)]. Polymer encapsulation was preferred by IBt in order to reduce the quantity of radioactive material needed for a given dose rate and to reduce the anisotropy of the radiation field around the seed. In addition, this design is intended to decrease the interseed effects that can occur as a result of the marker and the encapsulation. Dosimetric measurements were performed using LiF thermoluminescent dosimeters (1 mm{sup 3}) in solid water phantoms (WT1). Measured data were compared to Monte Carlo simulated data in solid water using the MCNP code, version 4C. Updated cross sections [Med. Phys. 30, 701-711 (2003)] were used. As the measured and calculated data were in agreement, Monte Carlo calculations were then

  19. Dosimetric effects of Onyx embolization on Gamma Knife arteriovenous malformation dose distributions.

    Science.gov (United States)

    Schlesinger, David J; Nordström, Håkan; Lundin, Anders; Xu, Zhiyuan; Sheehan, Jason P

    2016-12-01

    OBJECTIVE Patients with arteriovenous malformations (AVMs) treated with Gamma Knife radiosurgery (GKRS) subsequent to embolization suffer from elevated local failure rates and differences in adverse radiation effects. Onyx is a common embolic material for AVMs. Onyx is formulated with tantalum, a high atomic number (Z = 73) element that has been investigated as a source of dosimetric uncertainty contributing to the less favorable clinical results. However, prior studies have not modeled the complicated anatomical and beam geometries characteristic of GKRS. This study investigated the magnitude of dose perturbation that can occur due to Onyx embolization using clinically realistic anatomical and Gamma Knife beam models. METHODS Leksell GammaPlan (LGP) was used to segment the AVM nidus and areas of Onyx from postcontrast stereotactic MRI for 7 patients treated with GKRS postembolization. The resulting contours, skull surface, and clinically selected dose distributions were exported from LGP in DICOM-RT (Digital Imaging and Communications in Medicine-radiotherapy) format. Isocenter locations and dwell times were recorded from the LGP database. Contours were converted into 3D mesh representations using commercial and in-house mesh-editing software. The resulting data were imported into a Monte Carlo (MC) dose calculation engine (Pegasos, Elekta Instruments AB) with a beam geometry for the Gamma Knife Perfexion. The MC-predicted dose distributions were calculated with Onyx assigned manufacturer-reported physical constants (MC-Onyx), and then compared with corresponding distributions in which Onyx was reassigned constants for water (MC-water). Differences in dose metrics were determined, including minimum, maximum, and mean dose to the AVM nidus; selectivity index; and target coverage. Combined differences in dose magnitude and distance to agreement were calculated as 3D Gamma analysis passing rates using tolerance criteria of 0.5%/0.5 mm, 1.0%/1.0 mm, and 3.0%/3.0 mm

  20. Use of VAP3D software in the construction of pathological anthropomorphic phantoms for dosimetric evaluations; Uso do software VAP3D na construcao de fantomas antropomorficos patologicos para avaliacoes dosimetricas

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Lindeval Fernandes de [Universidade Federal de Pernambuco (DEM/UFPE), Recife, PE (Brazil). Dept. de Engenharia Mecanica; Vieira, Jose Wilson [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco, Recife, PE (Brazil); Lima, Fernando R.A., E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-10-26

    This paper performs a new type of dosimetric evaluation, where it was used a phantom of pathological voxels (representative phantom of sick person). The software VAP3D (Visualization and Analysis of Phantoms 3D) were used for, from a healthy phantom (phantom representative of healthy person), to introduce three dimensional regions to simulate tumors. It was used the Monte Carlo ESGnrc code to simulate the X ray photon transport, his interaction with matter and evaluation of absorbed dose in organs and tissues from thorax region of the healthy phantom and his pathological version. This is a computer model of typical exposure for programming the treatments in radiodiagnostic

  1. Characterization of quantity-quality grade conversion coefficient of supplementary cultivated land in Jianghan Plain, China

    Science.gov (United States)

    Hu, Shougeng; Wang, Jue; Wang, Zhanqi

    2010-11-01

    Relating supplementary cultivated land (SCL) quantity and quality with the occupied cultivated land (OCL) grade as well as realizing conversion between them are crucial to keep the balance between SCL and OCL, to protect the limited farming resources, to guarantee the security of national food, to harmonize the relationship between human and land resources, and to promote sustainable economic development. The Jianhan plain, one of China's grain production bases, was chosen for a case study to quantify the relationships between the grade index of farmland utilization and standard food output based on the resulting grade of agricultural land. Linear regression is used to model the relationships for 2778 samples from the grade of agricultural land obtained by field mapping. The average of grade index for different utilization grades was estimated by the area weighted average method. The results demonstrate that quantity-quality grade conversion coefficient of supplementary cultivated land, and the method used in this study are powerful tools to quantify the relationship between the quantity and quality of the SCL and the grade and realize conversion of OCL. Theses results can be used for protecting the quantity and quality of cultivated land and optimizing design for land consolidation project as well as determining the reasonable scale and layout of land use planning in the Jianghan plain.

  2. Tritium: An analysis of key environmental and dosimetric questions

    Energy Technology Data Exchange (ETDEWEB)

    Till, J E; Meyer, H R; Etnier, E L; Bomar, E S; Gentry, R D; Killough, G G; Rohwer, P S; Tennery, V J; Travis, C C

    1980-05-01

    This document summarizes new theoretical and experimental data that may affect the assessment of environmental releases of tritium and analyzes the significance of this information in terms of the dose to man. Calculated doses resulting from tritium releases to the environment are linearly dependent upon the quality factor chosen for tritium beta radiation. A reevaluation of the tritium quality factor by the ICRP is needed; a value of 1.7 would seem to be more justifiable than the old 1.0 value. A new exposure model is proposed, based primarily upon the approach recommended by the National Council on Radiation Protection and Measurements. Employing a /open quotes/typical/close quotes/ LMFBR reprocessing facility source term, a /open quotes/base case/close quotes/ dose commitment to total body (for a maximally exposed individual) was calculated to be 4.0 /times/ 10/sup /minus/2/ mSv, with 3.2 /times/ 10/sup /minus// mSv of the dose due to intake of tritium. The study analyzes models which exist for evaluating the buildup of global releases of tritium from man-made sources. Scenarios for the release of man-made tritium to the environment and prediction of collective dose commitment to future generations suggest that the dose from nuclear weapons testing will be less than that from nuclear energy even though the weapons source term is greater than that for any of our energy scenarios.

  3. Quantity, Quality, and Satisfaction with Mentoring: What Matters Most?

    Science.gov (United States)

    Xu, Xiaohong; Payne, Stephanie C.

    2014-01-01

    According to Kram's mentor role theory, satisfaction with mentoring and mentorship quality are key indicators of effective and successful mentoring. We contribute to mentoring research by demonstrating the relative importance of mentorship quantity, mentorship quality, and satisfaction with mentoring to the prediction of job satisfaction,…

  4. Predictors of Sleep Quantity and Quality in College Students

    Science.gov (United States)

    Davidson, Eric S.

    2012-01-01

    Whereas sleep is often thought of as a common health issue among college students, few, if any, researchers have comprehensively evaluated correlates and predictors of sleep quality and quantity within this population. Most often, studies of this type are used by researchers to assess particular categories of correlates and predictors (e.g.,…

  5. Early Numeracy Intervention: Does Quantity Discrimination Really Work?

    Science.gov (United States)

    Hansmann, Paul

    2013-01-01

    Scope and Method of Study: The current study demonstrates that a taped problem interve