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Sample records for models dosimetric quantities

  1. 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

    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). 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. 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. 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.

  2. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Using measurable dosimetric quantities to characterize the inter-structural tradeoff in inverse planning

    Science.gov (United States)

    Liu, Hongcheng; Dong, Peng; Xing, Lei

    2017-08-01

    Traditional inverse planning relies on the use of weighting factors to balance the conflicting requirements of different structures. Manual trial-and-error determination of weighting factors has long been recognized as a time-consuming part of treatment planning. The purpose of this work is to develop an inverse planning framework that parameterizes the dosimetric tradeoff among the structures with physically meaningful quantities to simplify the search for clinically sensible plans. In this formalism, instead of using weighting factors, the permissible variation range of the prescription dose or dose volume histogram (DVH) of the involved structures are used to characterize the ‘importance’ of the structures. The inverse planning is then formulated into a convex feasibility problem, called the dosimetric variation-controlled model (DVCM), whose goal is to generate plans with dosimetric or DVH variations of the structures consistent with the pre-specified values. For simplicity, the dosimetric variation range for a structure is extracted from a library of previous cases which possess similar anatomy and prescription. A two-phase procedure (TPP) is designed to solve the model. The first phase identifies a physically feasible plan to satisfy the prescribed dosimetric variation, and the second phase automatically improves the plan in case there is room for further improvement. The proposed technique is applied to plan two prostate cases and two head-and-neck cases and the results are compared with those obtained using a conventional CVaR approach and with a moment-based optimization scheme. Our results show that the strategy is able to generate clinically sensible plans with little trial and error. In all cases, the TPP generates a very competitive plan as compared to those obtained using the alternative approaches. Particularly, in the planning of one of the head-and-neck cases, the TPP leads to a non-trivial improvement in the resultant dose distribution

  5. Dosimetric lung models

    International Nuclear Information System (INIS)

    James, A.C.; Roy, M.

    1986-01-01

    The anatomical and physiological factors that vary with age and influence the deposition of airborne radionuclides in the lung are reviewed. The efficiency with which aerosols deposit in the lung for a given exposure at various ages from birth to adulthood is evaluated. Deposition within the lung is considered in relation to the clearance mechanisms acting in different regions or compartments. The procedure for evaluating dose to sensitive tissues in lung and transfer to other organs that is being considered by the Task Group established by ICRP to review the Lung Model is outlined. Examples of the application of this modelling procedure to evaluate lung dose as a function of age are given, for exposure to radon daughters in dwellings, and for exposure to an insoluble 239 Pu aerosol. The former represents exposure to short-lived radionuclides that deliver relatively high doses to bronchial tissue. In this case, dose rates are marginally higher in children than in adults. Plutonium exposure represents the case where dose is predominantly delivered to respiratory tissue and lymph nodes. In this case, the life-time doses tend to be lower for exposure in childhood. Some of the uncertainties in this modelling procedure are noted

  6. Dosimetric quantities and basic data for the evaluation of generalised derived limits

    International Nuclear Information System (INIS)

    Harrison, N.T.; Simmonds, J.R.

    1980-12-01

    The procedures, dosimetric quantities and basic data to be used for the evaluation of Generalised Derived Limits (GDLs) in environmental materials and of Generalised Derived Limits for discharges to atmosphere are described. The dosimetric considerations and the appropriate intake rates for both children and adults are discussed. In most situations in the nuclear industry and in those institutions, hospitals and laboratories which use relatively small quantities of radioactive material, the Generalised Derived Limits provide convenient reference levels against which the results of environmental monitoring can be compared, and atmospheric discharges can be assessed. They are intended for application when the environmental contamination or discharge to atmosphere is less than about 5% of the Generalised Derived Limit; above this level, it will usually be necessary to undertake a more detailed site-specific assessment. (author)

  7. Study of dosimetric quantities and image quality in pediatric examinations of chest and abdomen computed tomography

    International Nuclear Information System (INIS)

    Jornada, Tiago da Silva

    2013-01-01

    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

  8. Study of dosimetric quantities applied to patient undergoing routine chest examinations by computed tomography

    International Nuclear Information System (INIS)

    Gonzaga, Natalia Barbosa

    2012-01-01

    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 K,L ), organ equivalent dose (H 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 T and E and acceptable agreement for C W ,C VOL and P 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)

  9. Evaluation of Specific Absorption Rate as a Dosimetric Quantity for Electromagnetic Fields Bioeffects

    Science.gov (United States)

    Panagopoulos, Dimitris J.; Johansson, Olle; Carlo, George L.

    2013-01-01

    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 uncertainty to predict

  10. Model dosimetric for Radon and Daughters

    International Nuclear Information System (INIS)

    Puerta, J.A.; Cardenas, H.F.

    1998-01-01

    You elaborates a model dosimetric for radon and their products of decline of short half life starting from the new model of the breathing tract of the publication 66 of the ICRP and the use of the systemic models proposed in the publication 67, 68 and 69 of the same commission. The correlated used methodology the incorporation of these radionuclides with the activity in organs and you excrete, considering the difference of metabolic behavior of the products of decline and of their predecessor

  11. Calculation of Hazard Category 2/3 Threshold Quantities Using Contemporary Dosimetric Data

    Energy Technology Data Exchange (ETDEWEB)

    Walker, William C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-11-01

    The purpose of this report is to describe the methodology and selection of input data utilized to calculate updated Hazard Category 2 and Hazard Category 3 Threshold Quantities (TQs) using contemporary dosimetric information. The calculation of the updated TQs will be considered for use in the revision to the Department of Energy (DOE) Technical Standard (STD-) 1027-92 Change Notice (CN)-1, “Hazard Categorization and Accident Analysis Techniques for Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports.” The updated TQs documented in this report complement an effort previously undertaken by the National Nuclear Security Administration (NNSA), which in 2014 issued revised Supplemental Guidance documenting the calculation of updated TQs for approximately 100 radionuclides listed in DOE-STD-1027-92, CN-1. The calculations documented in this report complement the NNSA effort by expanding the set of radionuclides to more than 1,250 radionuclides with a published TQ. The development of this report was sponsored by the Department of Energy’s Office of Nuclear Safety (AU-30) within the Associate Under Secretary for Environment, Health, Safety, and Security organization.

  12. Adaptation of the present concept of dosimetric radiation protection quantities for external radiation to radiation protection practice

    International Nuclear Information System (INIS)

    Boehm, J.; Thompson, I. M. G.

    2004-01-01

    The present concept of dosimetric radiation protection quantities for external radiation is reviewed. For everyday application of the concept some adaptations are recommended. The check of the compliance with dose limits should be performed either by the comparison with values of the respective operational quantities directly or by the calculation of the protection quantity by means of the operational quantity, the appertaining conversion coefficient and additional information of the radiation field. Only four operational quantities are regarded to be sufficient for most applications in radiation protection practice. The term equivalent should be used in the connection dose equivalent only. Proposals are made for names of frequently used operational quantities which are denoted up to now by symbols only. (authors)

  13. Dosimetric model for intravascular brachytherapy

    International Nuclear Information System (INIS)

    Flower, E.E.; Stroud, D.B.

    2000-01-01

    Full text: Intravascular brachytherapy has been shown to be a prophylaxis for restenosis. Adventitial macrophages, which are extremely radiosensitive, initiate neointima formation. A model of the dose levels of the treatment range is developed, assuming that the adventitia is the target tissue. If the adventitia receives a dose of less than 10 Gy, it is assumed the treatment will be ineffective. If the dose to any part of the wall is above 30 Gy, it is assumed that the treatment could be detrimental. Hence the treatment range is between 10 and 30 Gy, with 20 Gy being the optimum dosage to the adventitia. An algorithm using numerical integration of published dose kernels calculates the dose at any point surrounding a beta ( 32 P) line source of finite length. Dose profiles were obtained to demonstrate edge effects. For long lesions, the source is often stepped along the artery. Dose changes due to separation or overlapping of sources during source stepping procedures were also determined. Isodose curves were superimposed on intravascular ultrasound images to demonstrate dose levels. For an exposure time of 60 seconds with a 200mCi source, the optimum dose of 20 Gy occurs at a distance 1.94mm from the centre of the source. The upper limit of the treatment dose range (30 Gy) occurs at 1.59mm. The lower limit of the treatment dose range (10 Gy) occurs at 2.7mm. Significant perturbations to the treatment dose range can be caused by non-centering of the source, edge effects and separation or overlapping of sources in stepping procedures. Despite these concerns, many successful procedures have been reported and this implies that the model is over simplified and requires modifications. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine

  14. Effect of XCOM photoelectric cross-sections on dosimetric quantities calculated with EGSnrc

    International Nuclear Information System (INIS)

    Hobeila, F.; Seuntjens, J.P.

    2002-01-01

    The EGSnrc Monte-Carlo code system incorporates improved low energy photon physics such as atomic relaxations and the implementation of bound Compton cross-sections using the impulse approximation. The total cross-section for photoelectric absorption however, still relies on the data by Storm and Israel (S and I). Yet, low energy applications such as brachytherapy (e.g. 125 I) require up-to-date low-energy photoelectric cross-section data. In this paper, we study the dosimetric effects of a simple implementation of NIST XCOM-based photoelectric cross-sections in EGSnrc. This is done by calculating mass energy-absorption coefficients, absorbed dose from point sources, kilovoltage x-ray beams and ion chamber response. In the EGS code system, the PEGS4 routine reads the photoelectric and pair cross-sections for elements from a file (pgspepr.dat) and provides numerical fits for compounds which will be used by EGSnrc. We updated the photoelectric cross-sections of the pgspepr.dat file with the XCOM total photoelectric absorption cross-sections from NIST. After validation of this new implementation, we studied its effects on a number of dosimetrically relevant quantities. Firstly, we calculated mass energy-absorption coefficients by scoring energy transferred in a thin slab of water and air using the DOSRZnrc user code. Secondly, we calculated inverse-square corrected absorbed dose distributions from point sources in water by using an internally developed user code, KERNELph. Thirdly, we studied the differences in free-air ion chamber response calculations. Ion chamber response is defined as the dose to the cavity of an ionization chamber, D gas , positioned with its effective point of measurement at a reference point divided by air-kerma measured free-in-air at the same point. The ion chamber response was calculated using monoenergetic photon beams of energy 10 keV to 200 keV. The comparison of the Storm and Israel photoelectric cross-sections with the XCOM cross

  15. Simulation of The ICRP-30 Dosimetric Model for the Respiratory Tract

    International Nuclear Information System (INIS)

    Giaddui, T.; Atia, M. A.

    2004-01-01

    Matlab was used to write a simulation program (ACID1) to simulate the ICRP-30 dosimetric model for the respiratory tract. The program (a new version of the one presented at the sixth Arab conference held in Cairo 2002) calculates a series of dosimetric quantities for the reference man as a result of the inhalation of any radionuclide. The program also plots the variation of activity with time for all organs and provided with a graphical user interface to make it friendly user. The results obtained by this program was compared with similar results obtained by other source and found to be very close. (Authors)

  16. A comprehensive method for calculating patient effective dose and other dosimetric quantities from CT DICOM images.

    Science.gov (United States)

    Tsalafoutas, Ioannis A; Thalassinou, Stella; Efstathopoulos, Efstathios P

    2012-07-01

    The purpose of this article is to present a method for the calculation of effective dose using the DICOM header information of CT images. Using specialized software, the DICOM data were automatically extracted into a spreadsheet containing embedded functions for calculating effective dose. These data were used to calculate the dose-length product (DLP) fraction that corresponds to each image, and the respective effective dose was obtained by multiplying the image DLP by a conversion coefficient that was automatically selected depending on the CT scanner, the tube potential, and the anatomic position to which each image corresponded. The total effective dose was calculated as the sum of effective doses of all images plus the contribution of overscan. The conversion coefficient tables were derived using dosimetry calculator software for both the International Commission on Radiological Protection (ICRP) 60 and ICRP 103 organ-weighting schemes. This method was applied for 90 chest, abdomen-pelvis, and chest-abdomen-pelvis examinations performed in three different MDCT scanners. The DLP values calculated with this method were in good agreement with those calculated by the CT scanners' software. The effective dose values calculated using the ICRP 103 conversion coefficient compared with those calculated using the ICRP 60 conversion coefficient were roughly equal for the chest-abdomen-pelvis examinations, smaller for the abdomen-pelvis examinations, and larger for the chest examinations. The applicability of this method for estimating organ doses was also explored. With this method, all patient dose-related quantities, such as the DLP, effective dose, and individual organ doses, can be calculated.

  17. Computational model for dosimetric purposes in dental procedures

    International Nuclear Information System (INIS)

    Kawamoto, Renato H.; Campos, Tarcisio R.

    2013-01-01

    This study aims to develop a computational model for dosimetric purposes the oral region, based on computational tools SISCODES and MCNP-5, to predict deterministic effects and minimize stochastic effects caused by ionizing radiation by radiodiagnosis. Based on a set of digital information provided by computed tomography, three-dimensional voxel model was created, and its tissues represented. The model was exported to the MCNP code. In association with SICODES, we used the Monte Carlo N-Particle Transport Code (MCNP-5) method to play the corresponding interaction of nuclear particles with human tissues statistical process. The study will serve as a source of data for dosimetric studies in the oral region, providing deterministic effect and minimize the stochastic effect of ionizing radiation

  18. 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.

  19. A biokinetic and dosimetric model for the metabolism of uranium

    International Nuclear Information System (INIS)

    Wrenn, M.E.; Bertelli, L.; Durbin, P.W.; Eckerman, K.F.; Lipsztein, J.L.; Singh, N.P.

    1995-10-01

    Experiments involving injection and inhalation of uranium compounds into several animal species as well as those associated with humans are described and analyzed. A revised biokinetic and dosimetric model for the metabolism of uranium suitable for bioassay procedures is proposed. The model consists of a systematic part coupled to a model of the respiratory tract. The model has been tested against human data which incorporates in vivo measurements over the chest and measurements of urine, feces, and autopsy and biopsy samples.In particular the lung model of the International Commission on Radiological Protection, Publication 30 ( ICRP-30 ), has been modified in order to provide a model which more nearly predicts urinary excretion in accord with the experiences in humans and animals. We have also tested the data against the new ICRP (LUDEP) lung model. (author). 55 refs., 14 tabs., 33 figs

  20. Dosimetric quantities in the ICRU sphere for neutron irradiation with energies between thermal and 20 MeV

    International Nuclear Information System (INIS)

    Hollnagel, R.; Jahr, R.; Siebert, B.R.L.

    1985-02-01

    The doses and dose equivalents produced in the ICRU sphere by broad unidirectional and monoenergetic neutron beams of energies between thermal and 20 MeV are calculated. The program employed makes use of the Monte Carlo method. In particular, the results for proposed operational radiation protection quantities (RPQ), i.e. specified-depth dose equivalent and ambient dose equivalent, are given. Quality factors, including those with and without induced photons, were derived for the proposed RPQ. Angular distribution factors for the irradiation of the ICRU sphere by beams other than a broad unidirectional beam are also presented. In Appendix A the relation of the proposed RPQ to those hitherto (ICRP 21) used is discussed. The tabulated dose equivalents in several depths of the ICRU sphere may be used as conversion factors in radiation protection when the ICRP 21 values are superseded by the proposed operational quantities. (orig.) [de

  1. A comprehensive approach to age-dependent dosimetric modeling

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, R.W.; Cristy, M.; Eckerman, K.F.

    1986-01-01

    In the absence of age-specific biokinetic models, current retention models of the International Commission on Radiological Protection (ICRP) frequently are used as a point of departure for evaluation of exposures to the general population. These models were designed and intended for estimation of long-term integrated doses to the adult worker. Their format and empirical basis preclude incorporation of much valuable physiological information and physiologically reasonable assumptions that could be used in characterizing the age-specific behavior of radioelements in humans. In this paper we discuss a comprehensive approach to age-dependent dosimetric modeling in which consideration is given not only to changes with age in masses and relative geometries of body organs and tissues but also to best available physiological and radiobiological information relating to the age-specific biobehavior of radionuclides. This approach is useful in obtaining more accurate estimates of long-term dose commitments as a function of age at intake, but it may be particularly valuable in establishing more accurate estimates of dose rate as a function of age. Age-specific dose rates are needed for a proper analysis of the potential effects on estimates or risk of elevated dose rates per unit intake in certain stages of life, elevated response per unit dose received during some stages of life, and age-specific non-radiogenic competing risks.

  2. A comprehensive approach to age-dependent dosimetric modeling

    International Nuclear Information System (INIS)

    Leggett, R.W.; Cristy, M.; Eckerman, K.F.

    1986-01-01

    In the absence of age-specific biokinetic models, current retention models of the International Commission on Radiological Protection (ICRP) frequently are used as a point of departure for evaluation of exposures to the general population. These models were designed and intended for estimation of long-term integrated doses to the adult worker. Their format and empirical basis preclude incorporation of much valuable physiological information and physiologically reasonable assumptions that could be used in characterizing the age-specific behavior of radioelements in humans. In this paper we discuss a comprehensive approach to age-dependent dosimetric modeling in which consideration is given not only to changes with age in masses and relative geometries of body organs and tissues but also to best available physiological and radiobiological information relating to the age-specific biobehavior of radionuclides. This approach is useful in obtaining more accurate estimates of long-term dose commitments as a function of age at intake, but it may be particularly valuable in establishing more accurate estimates of dose rate as a function of age. Age-specific dose rates are needed for a proper analysis of the potential effects on estimates or risk of elevated dose rates per unit intake in certain stages of life, elevated response per unit dose received during some stages of life, and age-specific non-radiogenic competing risks

  3. Model for predicting the quantity of water evaporated during oven ...

    African Journals Online (AJOL)

    Model for calculating the quantity of water that evaporated during oven drying of Otamiri clay has been derived. The model; j = exp ((In1/2.9206)18) showed that the quantity of water that evaporated during the drying process was dependent on the drying time, the evaporation surface being constant. It was found that the ...

  4. 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.

  5. 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.

  6. Sustainable economic production quantity models for inventory systems with shortage

    DEFF Research Database (Denmark)

    Taleizadeh, Ata Allah; Soleymanfar, Vahid Reza; Govindan, Kannan

    2018-01-01

    (EPQ). The theoretical sustainable EOQ and EPQ models are basic models that ignore many real-life conditions such as the possibility of stock-out in inventory systems. In this paper, we develop four new sustainable economic production quantity models that consider different shortage situations. To find...... optimal values of inventory system variables, we solve four independent profit maximization problems for four different situations. These proposed models include a basic model in which shortages are not allowed, and when shortages are allowed, the lost sale, full backordering and partial backordering...... models can be selected by operations managers depending on the manufacturer's motivation to improve service levels. We have also proposed an algorithm for determining optimum values of the decision variables for these sustainable economic production quantity models. Finally, the formulated models...

  7. 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.

  8. WE-AB-209-02: A New Inverse Planning Framework with Principle-Based Modeling of Inter-Structural Dosimetric Tradeoffs

    International Nuclear Information System (INIS)

    Liu, H; Dong, P; Xing, L

    2016-01-01

    Purpose: Traditional radiotherapy inverse planning relies on the weighting factors to phenomenologically balance the conflicting criteria for different structures. The resulting manual trial-and-error determination of the weights has long been recognized as the most time-consuming part of treatment planning. The purpose of this work is to develop an inverse planning framework that parameterizes the inter-structural dosimetric tradeoff among with physically more meaningful quantities to simplify the search for a clinically sensible plan. Methods: A permissible dosimetric uncertainty is introduced for each of the structures to balance their conflicting dosimetric requirements. The inverse planning is then formulated as a convex feasibility problem, which aims to generate plans with acceptable dosimetric uncertainties. A sequential procedure (SP) is derived to decompose the model into three submodels to constrain the uncertainty in the planning target volume (PTV), the critical structures, and all other structures to spare, sequentially. The proposed technique is applied to plan a liver case and a head-and-neck case and compared with a conventional approach. Results: Our results show that the strategy is able to generate clinically sensible plans with little trial-and-error. In the case of liver IMRT, the fractional volumes to liver and heart above 20Gy are found to be 22% and 10%, respectively, which are 15.1% and 33.3% lower than that of the counterpart conventional plan while maintaining the same PTV coverage. The planning of the head and neck IMRT show the same level of success, with the DVHs for all organs at risk and PTV very competitive to a counterpart plan. Conclusion: A new inverse planning framework has been established. With physically more meaningful modeling of the inter-structural tradeoff, the technique enables us to substantially reduce the need for trial-and-error adjustment of the model parameters and opens new opportunities of incorporating prior

  9. 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.

  10. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Computer modeling of dosimetric pattern in aquatic environment of ...

    African Journals Online (AJOL)

    The dose distribution functions for the three sources of radiation in the environment have been reviewed. The model representing the geometry of aquatic organisms have been employed in computationally solving the dose rates to aquatic organisms with emphasis on the coastal areas of Nigeria where oil exploration ...

  13. Voxel models representing the male and female ICRP reference adult: a dosimetric tool for medical imaging

    Science.gov (United States)

    Zankl, M.; Schlattl, H.; Becker, J.; Petoussi-Henss, N.; Hoeschen, C.

    2008-03-01

    For optimisation in diagnostic medical imaging it is important to consider the relation between diagnostic image quality and patient dose. In the past, schematic representations of the human body were commonly used for dosimetric simulations together with Monte Carlo codes. During the last two decades, voxel models were introduced as an improvement to these body models. Studies performed by various research groups have shown that the more realistic organ topology of voxel models constructed from medical image data of real persons has an impact on calculated doses for external as well as internal exposures. As a consequence of these findings, the ICRP decided to use voxel models for the forthcoming update of organ dose conversion coefficients. These voxel models should be representative of an average population, i.e. they should resemble the ICRP reference anatomical data with respect to their external dimensions and their organ masses. To meet the ICRP requirements, our group at the Helmholtz Zentrum München (formerly known as GSF-National Research Center for Environment and Health) constructed voxel models of a male and female adult, based on the voxel models of two individuals whose body height and weight resembled those of the male and female ICRP reference adult. The organ masses of both models were adjusted to the ICRP reference anatomical data, without spoiling their realistic anatomy. The paper describes the method used for this process and the resulting voxel models.

  14. SU-F-BRB-13: Correlation of Improved Target and Organ-At-Risk Dosimetric Quantities and Clinical Outcomes for Helical Tomotherapy Treated Mesothelioma

    Energy Technology Data Exchange (ETDEWEB)

    Qi, S; Kishan, A; Alexander, S; Lee, P; Selch, M; Kupelian, P; Steiberg, M; Low, D [UCLA, Los Angeles, CA (United States)

    2015-06-15

    Purpose: We have observed improved local control probability (LCP) for adjuvant mesothelioma radiotherapy following pleurectomy/decortication using Tomotherapy compared to the conventional 3D technique (p<0.05). This work assesses the correlation between the improved clinical outcomes against dosimetry quantities. Methods: Thirty-eight mesothelioma cases consecutively treated at our clinic were retrospectively analyzed. Sixteen patients were treated using 3D technique planned on the Eclipse for c-arm accelerators prior to 7/2012; the other 22 cases were treated on Tomotherapy using helical IMRT after 7/2012. Typical 3D plans consisting of 15 MV AP/PA photon fields prescribed to 10 cm depth followed by matching electron fields with energy ranging from 8–16 MeV. Tomotherapy plans were designed using 2.5cm jaw, 0.287 pitch with directional blocking of the contralateral lung. The same prescription of 45 Gy (1.8GyX25) was used for both techniques. The dosimetry metrics for the critical structures: ipsilateral-/contralateral-lung, heart, cord, esophagus, etc were compared between two techniques. Results: Superior LCP is closely associated with improved target coverage. Tomotherapy plans yielded dramatically better target coverage and less dose heterogeneity despite of more advanced/larger disease. The averaged PTV volumes were 2287.3±569.9 (Tomotherapy) vs. 1904.8±312.3cc (3D); V100s were: 91.1±4.0 (%) vs. 47.8±12.7 (%) with heterogeneity indices of 1.20±0.1 vs.1.37±0.38 and for the Tomotherapy and 3D plans, respectively. Compared to the 3D technique, we observed significant lower maximum cord doses (p<0.001), lower mean esophagus doses (p<0.002), and lower heart mean doses when tumor was left-sided (p=0.002). For ipsilateral-/contralateral-lungs, however, the mean doses and V20, V5 of Tomotherapy plans were significantly higher than the 3D plans (p<0.01) regardless which sides of lung were treated. However, rates of radiation pneumonitis were no different

  15. Evaluation of physiological parameters and their influence on doses calculated from two alternative dosimetric models for the gastrointestinal tract

    International Nuclear Information System (INIS)

    Lessard, E.T.; Skrable, K.W.

    1981-01-01

    Two dosimetric models, the catenary compartmental model and the slug flow model are examined using three sets of physiological parameters. The impact of physiological parameters on the dosimetry of the tract is illustrated by comparing calculated maximum permissible daily activity ingestion rates for single, unabsorbed, particle emitting radionuclides with an effective energy term of unity. The conclusions drawn from this intercomparison of six different cases are: (1) Current dosimetric models which use physiological parameters described in this article do not significantly disagree, and (2) For the determination of average dose equivalent rates to segments of the tract due to chronic, long term ingestion of any radionuclide, the catenary compartmental model is a mathematically simpler approach. The catenary model in addition has certain advantages for the calculation of the photon dose contribution to one segment from cumulated activity (disintegrations) in another segment

  16. 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

  17. 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.

  18. Using a Monte Carlo model to predict dosimetric properties of small radiotherapy photon fields

    International Nuclear Information System (INIS)

    Scott, Alison J. D.; Nahum, Alan E.; Fenwick, John D.

    2008-01-01

    Accurate characterization of small-field dosimetry requires measurements to be made with precisely aligned specialized detectors and is thus time consuming and error prone. This work explores measurement differences between detectors by using a Monte Carlo model matched to large-field data to predict properties of smaller fields. Measurements made with a variety of detectors have been compared with calculated results to assess their validity and explore reasons for differences. Unshielded diodes are expected to produce some of the most useful data, as their small sensitive cross sections give good resolution whilst their energy dependence is shown to vary little with depth in a 15 MV linac beam. Their response is shown to be constant with field size over the range 1-10 cm, with a correction of 3% needed for a field size of 0.5 cm. BEAMnrc has been used to create a 15 MV beam model, matched to dosimetric data for square fields larger than 3 cm, and producing small-field profiles and percentage depth doses (PDDs) that agree well with unshielded diode data for field sizes down to 0.5 cm. For fields sizes of 1.5 cm and above, little detector-to-detector variation exists in measured output factors, however for a 0.5 cm field a relative spread of 18% is seen between output factors measured with different detectors--values measured with the diamond and pinpoint detectors lying below that of the unshielded diode, with the shielded diode value being higher. Relative to the corrected unshielded diode measurement, the Monte Carlo modeled output factor is 4.5% low, a discrepancy that is probably due to the focal spot fluence profile and source occlusion modeling. The large-field Monte Carlo model can, therefore, currently be used to predict small-field profiles and PDDs measured with an unshielded diode. However, determination of output factors for the smallest fields requires a more detailed model of focal spot fluence and source occlusion.

  19. Evaluation of physiological parameters and their influence on doses calculated from two alternative dosimetric models for the gastrointestinal tract

    International Nuclear Information System (INIS)

    Lessard, E.T.; Skrable, K.W.

    1981-01-01

    Two dosimetric models, the catenary compartmental model (Be70) and the slug flow model (Sk75), are examined using three sets of physiological parameters: those proposed by Eve, those proposed by ICRP, and those obtained from the Textbook of Physiology and Biochemistry by Bell et al. The impact of physiological parameters on the dosimetry of the tract is illustrated by comparing calculated maximum permissible daily activity ingestion rates for single, unabsorbed, particle emitting radionuclides with an effective energy term of unity. The conclusions drawn from this intercomparison of six different cases are: Current dosimetric models which use physiological parameters described in this article do not significantly disagree, and for the determination of average dose equivalent rates to segments of the tract due to chronic, long term ingestion of any radionuclide, the catenary compartmental model is a mathematically simpler approach. The catenary model in addition has certain advantages for the calculation of the photon dose contribution to one segment from cumulated activity (disintegrations) in another segment

  20. Model-based versus specific dosimetry in diagnostic context: Comparison of three dosimetric approaches

    Energy Technology Data Exchange (ETDEWEB)

    Marcatili, S., E-mail: sara.marcatili@inserm.fr; Villoing, D.; Mauxion, T.; Bardiès, M. [Inserm, UMR1037 CRCT, Toulouse F-31000, France and Université Toulouse III-Paul Sabatier, UMR1037 CRCT, Toulouse F-31000 (France); McParland, B. J. [Imaging Technology Group, GE Healthcare, Life Sciences, B22U The Grove Centre, White Lion Road, Amersham, England HP7 9LL (United Kingdom)

    2015-03-15

    Purpose: The dosimetric assessment of novel radiotracers represents a legal requirement in most countries. While the techniques for the computation of internal absorbed dose in a therapeutic context have made huge progresses in recent years, in a diagnostic scenario the absorbed dose is usually extracted from model-based lookup tables, most often derived from International Commission on Radiological Protection (ICRP) or Medical Internal Radiation Dose (MIRD) Committee models. The level of approximation introduced by these models may impact the resulting dosimetry. The aim of this work is to establish whether a more refined approach to dosimetry can be implemented in nuclear medicine diagnostics, by analyzing a specific case. Methods: The authors calculated absorbed doses to various organs in six healthy volunteers administered with flutemetamol ({sup 18}F) injection. Each patient underwent from 8 to 10 whole body 3D PET/CT scans. This dataset was analyzed using a Monte Carlo (MC) application developed in-house using the toolkit GATE that is capable to take into account patient-specific anatomy and radiotracer distribution at the voxel level. They compared the absorbed doses obtained with GATE to those calculated with two commercially available software: OLINDA/EXM and STRATOS implementing a dose voxel kernel convolution approach. Results: Absorbed doses calculated with GATE were higher than those calculated with OLINDA. The average ratio between GATE absorbed doses and OLINDA’s was 1.38 ± 0.34 σ (from 0.93 to 2.23). The discrepancy was particularly high for the thyroid, with an average GATE/OLINDA ratio of 1.97 ± 0.83 σ for the six patients. Differences between STRATOS and GATE were found to be higher. The average ratio between GATE and STRATOS absorbed doses was 2.51 ± 1.21 σ (from 1.09 to 6.06). Conclusions: This study demonstrates how the choice of the absorbed dose calculation algorithm may introduce a bias when gamma radiations are of importance, as is

  1. 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.

  2. Machine Learning and Deep Learning Models to Predict Runoff Water Quantity and Quality

    Science.gov (United States)

    Bradford, S. A.; Liang, J.; Li, W.; Murata, T.; Simunek, J.

    2017-12-01

    Contaminants can be rapidly transported at the soil surface by runoff to surface water bodies. Physically-based models, which are based on the mathematical description of main hydrological processes, are key tools for predicting surface water impairment. Along with physically-based models, data-driven models are becoming increasingly popular for describing the behavior of hydrological and water resources systems since these models can be used to complement or even replace physically based-models. In this presentation we propose a new data-driven model as an alternative to a physically-based overland flow and transport model. First, we have developed a physically-based numerical model to simulate overland flow and contaminant transport (the HYDRUS-1D overland flow module). A large number of numerical simulations were carried out to develop a database containing information about the impact of various input parameters (weather patterns, surface topography, vegetation, soil conditions, contaminants, and best management practices) on runoff water quantity and quality outputs. This database was used to train data-driven models. Three different methods (Neural Networks, Support Vector Machines, and Recurrence Neural Networks) were explored to prepare input- output functional relations. Results demonstrate the ability and limitations of machine learning and deep learning models to predict runoff water quantity and quality.

  3. 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.

  4. 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.

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

    International Nuclear Information System (INIS)

    Intharathirat, Rotchana; Abdul Salam, P.; Kumar, S.; Untong, Akarapong

    2015-01-01

    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

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

    OpenAIRE

    Qin Juanjuan

    2012-01-01

    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 paramet...

  7. 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.

  8. Competitive quantity discounts

    OpenAIRE

    Calzolari, Giacomo; Denicolò, Vincenzo

    2010-01-01

    We analyze the effects of competition with quantity discounts in a duopoly model with asymmetric firms. Consumers are privately informed about demand, so firms use quantity discounts as a price discrimination device. However, a dominant firm may also use quantity discounts to weaken or eliminate its competitor. We analyze the effects of quantity discounts on firms' profits and consumer surplus. Our main finding is that quantity discounts can decrease social welfare (i.e., the sum of producers...

  9. A Novel Experimental and Modelling Strategy for Nanoparticle Toxicity Testing Enabling the Use of Small Quantities

    Directory of Open Access Journals (Sweden)

    Marinda van Pomeren

    2017-11-01

    Full Text Available Metallic nanoparticles (NPs differ from other metal forms with respect to their large surface to volume ratio and subsequent inherent reactivity. Each new modification to a nanoparticle alters the surface to volume ratio, fate and subsequently the toxicity of the particle. Newly-engineered NPs are commonly available only in low quantities whereas, in general, rather large amounts are needed for fate characterizations and effect studies. This challenge is especially relevant for those NPs that have low inherent toxicity combined with low bioavailability. Therefore, within our study, we developed new testing strategies that enable working with low quantities of NPs. The experimental testing method was tailor-made for NPs, whereas we also developed translational models based on different dose-metrics allowing to determine dose-response predictions for NPs. Both the experimental method and the predictive models were verified on the basis of experimental effect data collected using zebrafish embryos exposed to metallic NPs in a range of different chemical compositions and shapes. It was found that the variance in the effect data in the dose-response predictions was best explained by the minimal diameter of the NPs, whereas the data confirmed that the predictive model is widely applicable to soluble metallic NPs. The experimental and model approach developed in our study support the development of (ecotoxicity assays tailored to nano-specific features.

  10. A Novel Experimental and Modelling Strategy for Nanoparticle Toxicity Testing Enabling the Use of Small Quantities.

    Science.gov (United States)

    van Pomeren, Marinda; Peijnenburg, Willie J G M; Brun, Nadja R; Vijver, Martina G

    2017-11-06

    Metallic nanoparticles (NPs) differ from other metal forms with respect to their large surface to volume ratio and subsequent inherent reactivity. Each new modification to a nanoparticle alters the surface to volume ratio, fate and subsequently the toxicity of the particle. Newly-engineered NPs are commonly available only in low quantities whereas, in general, rather large amounts are needed for fate characterizations and effect studies. This challenge is especially relevant for those NPs that have low inherent toxicity combined with low bioavailability. Therefore, within our study, we developed new testing strategies that enable working with low quantities of NPs. The experimental testing method was tailor-made for NPs, whereas we also developed translational models based on different dose-metrics allowing to determine dose-response predictions for NPs. Both the experimental method and the predictive models were verified on the basis of experimental effect data collected using zebrafish embryos exposed to metallic NPs in a range of different chemical compositions and shapes. It was found that the variance in the effect data in the dose-response predictions was best explained by the minimal diameter of the NPs, whereas the data confirmed that the predictive model is widely applicable to soluble metallic NPs. The experimental and model approach developed in our study support the development of (eco)toxicity assays tailored to nano-specific features.

  11. Procurement-distribution model for perishable items with quantity discounts incorporating freight policies under fuzzy environment

    Directory of Open Access Journals (Sweden)

    Makkar Sandhya

    2013-01-01

    Full Text Available A significant issue of the supply chain problem is how to integrate different entities. Managing supply chain is a difficult task because of complex integrations, especially when the products are perishable in nature. Little attention has been paid on ordering specific perishable products jointly in uncertain environment with multiple sources and multiple destinations. In this article, we propose a supply chain coordination model through quantity and freight discount policy for perishable products under uncertain cost and demand information. A case is provided to validate the procedure.

  12. 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 an enterprise has two types of demand, continue and discrete demand, the basic EPQ would be no longer useful. Demand continues comes from a customer who wants their needs to be fulfilled every time per unit time, while the fulfillment of demand discrete is at a fixed interval of time. A 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 tries to develop EPQ model considering two types of demand simultaneously.

  13. 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

    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...... 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 specific advantages and disadvantages of each method. In relation to computational efficiency (i.e. number of iterations required to generate the probability distribution of parameters), it was found that SCEM-UA and AMALGAM produce results quicker than GLUE in terms of required number of simulations...

  14. 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

  15. Coupled Model Development between Groundwater Recharge Quantity and Climate Change in Nakdong River Watershed using GIS

    Science.gov (United States)

    Lee, M.; Jeongho, L.; Changsub, S.; SeongWoo, J.

    2011-12-01

    : Global climate change is disturbing the water circulation balance by changing rates of precipitation, recharge and discharge, and evapotranspiration. Groundwater, which occupies a considerable portion of the world's water resources, is related to climate change via surface water such as rivers, lakes, and marshes. In this study, the authors selected a relevant climate change scenario, A1B from the Special Report on Emission Scenario (SRES) which is distributed at Korea Meteorological Administration. By using data on temperature, rainfall, soil, and land use, the groundwater recharge rate for the research area was estimated by periodically and embodied as geographic information system (GIS). In order to calculate the groundwater recharge quantity, Visual HELP3 was used as main model, and the physical properties of weather, temperature, and soil layers were used as main input data. General changes to water circulation due to climate change have already been predicted. In order to systematically solve problems of ground circulation system, it may be urgent to recalculate the groundwater recharge quantity and consequent change under future climate change. The space-time calculation of changes of the groundwater recharge quantity in the study area may serve as a foundation to present additional measures to improve domestic groundwater resource management. Results showed that 26.19% of total precipitation was recharged from 1971 to 2000, 27.37% will be recharged from 2001 to 2030, 27.43% will be recharged from 2031 to 2050, and 26.06% will be recharged from 2051 to 2070, 27.88% will be recharged from 2051 to 2100. The groundwater recharge rate in this research showed susceptibility to changes in precipitation. The recharge rate was relatively little affected by the changes in Curve Number (CN), but it was rapidly reduced, as it approached the impermeable layers. Accordingly, the findings herein provide a basis for establishment of national plans on water resources

  16. Using a Content Management System for Integrated Water Quantity, Quality and Instream Flows Modeling

    Science.gov (United States)

    Burgholzer, R.; Brogan, C. O.; Scott, D.; Keys, T.

    2017-12-01

    With increased population and water demand, in-stream flows can become depleted by consumptive uses and dilution of permitted discharges may be compromised. Reduced flows downstream of water withdrawals may increase the violation rate of bacterial concentrations from direct deposition by livestock and wildlife. Water storage reservoirs are constructed and operated to insure more stable supplies for consumptive demands and dilution flows, however their use comes at the cost of increased evaporative losses, potential for thermal pollution, interrupted fish migration, and reduced flooding events that are critical to maintain habitat and water quality. Due to this complex interrelationship between water quantity, quality and instream habitat comprehensive multi-disciplinary models must be developed to insure long-term sustainability of water resources and to avoid conflicts between drinking water, food and energy production, and aquatic biota. The Commonwealth of Virginia funded the expansion of the Chesapeake Bay Program Phase 5 model to cover the entire state, and has been using this model to evaluate water supply permit and planning since 2009. This integrated modeling system combines a content management system (Drupal and PHP) for model input data and leverages the modularity of HSPF with the custom segmentation and parameterization routines programmed by modelers working with the Chesapeake Bay Program. The model has been applied to over 30 Virginia Water Permits, instream flows and aquatic habitat models and a Virginias 30 year water supply demand projections. Future versions will leverage the Bay Model auto-calibration routines for adding small-scale water supply and TMDL models, utilize climate change scenarios, and integrate Virginia's reservoir management modules into the Chesapeake Bay watershed model, feeding projected demand and operational changes back up to EPA models to improve the realism of future Bay-wide simulations.

  17. 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. Copyright © 2016. Published by Elsevier B.V.

  18. Slice-based supine-to-standing posture deformation for chinese anatomical models and the dosimetric results with wide band frequency electromagnetic field exposure: Simulation

    International Nuclear Information System (INIS)

    Wu, T.; Tan, L.; Shao, Q.; Li, Y.; Yang, L.; Zhao, C.; Xie, Y.; Zhang, S.

    2013-01-01

    Standing Chinese adult anatomical models are obtained from supine-postured cadaver slices. This paper presents the dosimetric differences between the supine and the standing postures over wide band frequencies and various incident configurations. Both the body level and the tissue/organ level differences are reported for plane wave and the 3T magnetic resonance imaging radiofrequency electromagnetic field exposure. The influence of posture on the whole body specific absorption rate and tissue specified specific absorption rate values is discussed. . (authors)

  19. An improved mathematical model for prediction of air quantity to minimise radiation levels in underground uranium mines.

    Science.gov (United States)

    Panigrahi, Durga Charan; Sahu, Patitapaban; Mishra, Devi Prasad

    2015-02-01

    Ventilation is the primary means of controlling radon and its daughter concentrations in an underground uranium mine environment. Therefore, prediction of air quantity is the vital component for planning and designing of ventilation systems to minimise the radiation exposure of miners in underground uranium mines. This paper comprehensively describes the derivation and verification of an improved mathematical model for prediction of air quantity, based on the growth of radon daughters in terms of potential alpha energy concentration (PAEC), to reduce the radiation levels in uranium mines. The model also explains the prediction of air quantity depending upon the quality of intake air to the stopes. This model can be used to evaluate the contribution of different sources to radon concentration in mine atmosphere based on the measurements of radon emanation and exhalation. Moreover, a mathematical relationship has been established for quick prediction of air quantity to achieve the desired radon daughter concentration in the mines. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Validation of SWAT+ at field level and comparison with previous SWAT models in simulating hydrologic quantity

    Science.gov (United States)

    GAO, J.; White, M. J.; Bieger, K.; Yen, H.; Arnold, J. G.

    2017-12-01

    Over the past 20 years, the Soil and Water Assessment Tool (SWAT) has been adopted by many researches to assess water quantity and quality in watersheds around the world. As the demand increases in facilitating model support, maintenance, and future development, the SWAT source code and data have undergone major modifications over the past few years. To make the model more flexible in terms of interactions of spatial units and processes occurring in watersheds, a completely revised version of SWAT (SWAT+) was developed to improve SWAT's ability in water resource modelling and management. There are only several applications of SWAT+ in large watersheds, however, no study pays attention to validate the new model at field level and assess its performance. To test the basic hydrologic function of SWAT+, it was implemented in five field cases across five states in the U.S. and compared the SWAT+ created results with that from the previous models at the same fields. Additionally, an automatic calibration tool was used to test which model is easier to be calibrated well in a limited number of parameter adjustments. The goal of the study was to evaluate the performance of SWAT+ in simulating stream flow on field level at different geographical locations. The results demonstrate that SWAT+ demonstrated similar performance with previous SWAT model, but the flexibility offered by SWAT+ via the connection of different spatial objects can result in a more accurate simulation of hydrological processes in spatial, especially for watershed with artificial facilities. Autocalibration shows that SWAT+ is much easier to obtain a satisfied result compared with the previous SWAT. Although many capabilities have already been enhanced in SWAT+, there exist inaccuracies in simulation. This insufficiency will be improved with advancements in scientific knowledge on hydrologic process in specific watersheds. Currently, SWAT+ is prerelease, and any errors are being addressed.

  1. Satellite Data and Hydrological Model to Asses Water Quantity and Quality in the Yangtze River Basin

    Science.gov (United States)

    Mancini, Marco; Corbari, Chiara; Di Trapani, Antonio; Li, Jiren; Xin, Jinfeng; Zhang, Jianli; Zhang, Xingnan; Su, Bob; Yesou, Herve

    2016-08-01

    The main objective of the project is to assess water quantity and quality for the Yangtze River basin through remote sensing data and a distributed hydrological model. The paper provides an overview of the project activities that are supported by several peer review articles to which we refer for details. Water quantity analyses are assed with the fully distributed hydrological model FEST-EWB. The model algorithm solves the system of energy and mass balances in terms of a representative equilibrium temperature (RET) that is the land surface temperature that closes the energy balance equation and so governs the fluxes of energy and mass over the basin domain. This equilibrium surface temperature, which is a critical model state variable, is comparable to LST as retrieved from operational remote sensing data (MODIS) which is used for the calibration of soil and vegetation parameters. The effects on river discharge of the Three Gorges dam, the largest hydropower project in the world is evaluated. Observed flow duration curves, for the four available river cross sections, will be evaluated and compared to FEST- EWB simulated flow duration curves as well as observed as simulated hydrographs.The dynamic of the three large lakes (Poyang, Dongting and Taihu), which change considerably their area during the seasons, will also be analyzed using MERIS and ASAR data to infer surface area changes and LEGOS altimetry data (Topex/Poseidon, Jason, ENVISAT) for water level. Data from 2003 to 2006 are evaluated.FEST-EWB is run in for the whole Yangtze River basin at spatial resolution of 0.05° and temporal resolution of 3 hours. Results are provided in terms of hourly evapotranspiration, soil moisture and land surface temperature maps for the period between 2003 to 2006 and flood hydrographs at different river cross sections.Water quality analyses are performed along the Yangtze river estimating turbidity and suspended solid sediments from MERIS (250 m) and MODIS (300 m) data using

  2. Pengembangan Soal Matematika Model PISA pada Konten Quantity untuk Mengukur Kemampuan Pemecahan Masalah Matematika Siswa Sekolah Menengah Pertama

    Directory of Open Access Journals (Sweden)

    Febrina Bidasari

    2017-03-01

    Full Text Available Penelitian ini bertujuan untuk: (1 menghasilkan soal-soal model PISA pada konten quantity untuk mengukur kemampuan pemecahan masalah matematika siswa SMP yang valid dan praktis, (2 mengetahui efek potensial soal-soal model PISA pada quantity terhadap kemampuan pemecahan masalah matematika siswa SMP. Metode Penelitian ini merupakan metode penelitian pengembangan.  Subjek penelitian ini adalah siswa kelas IX.2 SMP Negeri 17 Palembang sebanyak 36 siswa. Teknik pengumpulan data yang digunakan dalam penelitian ini adalah walk through dan tes. Dari hasil analisis dapat disimpulkan bahwa penelitian ini telah menghasilkan (1 suatu produk soal matematika model PISA konten quantity sejumlah 12 soal berbentuk soal uraian non objektif dan dilengkapi dengan kisi-kisi, dan kartu soal. (2 prototype soal matematika model PISA konten quantity yang dikembangkan mempunyai efek potensial terhadap kemampuan pemecahan masalah matematika siswa dimana skor rata-rata siswa mencapai 54,64 yang dikategorikan baik. Kata Kunci: penelitian pengembangan, soal-soal PISA konten quantity This study aims to: (1 produce valid and practical PISA based problems on quantity content to examine Junior High School students problem solving skill; (2 recognize the potential effect of those problems to students problem solving skill. Research and development was the method of the study. There were 36 ninth graders of SMP Negeri 17 Palembang as the subject of the study. Walk through and test were two ways conducted to obtain data. The result showed (1 PISA based problem on quantity content were already constructed followed by its blueprint, and question cards; (2 the prototype had potential effect towards students problem solving skill which scored 54.64 and categorized good. Keywords: research and development, PISA based problems on quantity content

  3. 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

  4. 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.

  5. 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.

  6. Water quantity and quality optimization modeling of dams operation based on SWAT in Wenyu River Catchment, China.

    Science.gov (United States)

    Zhang, Yongyong; Xia, Jun; Chen, Junfeng; Zhang, Minghua

    2011-02-01

    Water quantity and quality joint operation is a new mode in the present dams' operation research. It has become a hot topic in governmental efforts toward integrated basin improvement. This paper coupled a water quantity and quality joint operation model (QCmode) and genetic algorithm with Soil and Water Assessment Tool (SWAT). Together, these tools were used to explore a reasonable operation of dams and floodgates at the basin scale. Wenyu River Catchment, a key area in Beijing, was selected as the case study. Results showed that the coupled water quantity and quality model of Wenyu River Catchment more realistically simulates the process of water quantity and quality control by dams and floodgates. This integrated model provides the foundation for research of water quantity and quality optimization on dam operation in Wenyu River Catchment. The results of this modeling also suggest that current water quality of Wenyu River will improve following the implementation of the optimized operation of the main dams and floodgates. By pollution control and water quantity and quality joint operation of dams and floodgates, water quality of Wenyu river will change significantly, and the available water resources will increase by 134%, 32%, 17%, and 82% at the downstream sites of Sha River Reservoir, Lutong Floodgate, Xinpu Floodgate, and Weigou Floodgate, respectively. The water quantity and quality joint operation of dams will play an active role in improving water quality and water use efficiency in Wenyu River Basin. The research will provide the technical support for water pollution control and ecological restoration in Wenyu River Catchment and could be applied to other basins with large number of dams. Its application to the Wenyu River Catchment has a great significance for the sustainable economic development of Beijing City.

  7. Theoretical and experimental determination of dosimetric characteristics for brachyseedTM Pd-103, model Pd-1, source

    International Nuclear Information System (INIS)

    Meigooni, A.S.; Zhang Hualin; Perry, Candace; Dini, S.A.; Koona, R.A.

    2003-01-01

    Dosimetric characteristics of the BrachySeed TM Pd-103, Model Pd-1 source have been determined using both theoretical and experimental methods. Dose rate constant, radial dose function, and anisotropy functions of the source have been obtained following the TG-43 recommendations. Derivation of the dose rate constant was based on recent NIST WAFAC calibration performed in accordance with their 1999 Standard. Measurements were performed in Solid Water TM using LiF TLD chips. Theoretical simulation calculations were performed in both Solid Water TM and water phantom materials using MCNP4C2 Monte Carlo code using DLC-200 interaction data. The results of the Monte Carlo simulation indicated a dose rate constant of 0.65 cGy h -1 U -1 and 0.61 cGy h -1 U -1 in water and Solid Water TM , respectively. The measured dose rate constant in Solid Water TM was found to be 0.63±7% cGy h -1 U -1 , which is within the experimental uncertainty of the Monte-Carlo simulated results. The anisotropy functions of the source were calculated in both water and in Solid Water TM at the radial distances of 1 to 7 cm. Measurements were made in Solid Water TM at distances of 2, 3, 5, and 7 cm. The Monte-Carlo calculated anisotropy constant of the new source was found to be 0.98 in water. The tabulated data and 5th order polynomial fit coefficients for the radial dose function along with the dose rate constant and anisotropy functions are provided to support clinical use of this source

  8. A dosimetric model for the heterogeneous delivery of radioactive nanoparticles In vivo: a feasibility study.

    Science.gov (United States)

    Satterlee, Andrew B; Attayek, Peter; Midkiff, Bentley; Huang, Leaf

    2017-03-17

    ᅟ: Accurate and quantitative dosimetry for internal radiation therapy can be especially challenging, given the heterogeneity of patient anatomy, tumor anatomy, and source deposition. Internal radiotherapy sources such as nanoparticles and monoclonal antibodies require high resolution imaging to accurately model the heterogeneous distribution of these sources in the tumor. The resolution of nuclear imaging modalities is not high enough to measure the heterogeneity of intratumoral nanoparticle deposition or intratumoral regions, and mathematical models do not represent the actual heterogeneous dose or dose response. To help answer questions at the interface of tumor dosimetry and tumor biology, we have modeled the actual 3-dimensional dose distribution of heterogeneously delivered radioactive nanoparticles in a tumor after systemic injection. 24 h after systemic injection of dually fluorescent and radioactive nanoparticles into a tumor-bearing mouse, the tumor was cut into 342 adjacent sections and imaged to quantify the source distribution in each section. The images were stacked to generate a 3D model of source distribution, and a novel MATLAB code was employed to calculate the dose to cells on a middle section in the tumor using a low step size dose kernel. The average dose calculated by this novel 3D model compared closely with standard ways of calculating average dose, and showed a positive correlation with experimentally determined cytotoxicity in vivo. The high resolution images allowed us to determine that the dose required to initiate radiation-induced H2AX phosphorylation was approximately one Gray. The nanoparticle distribution was further used to model the dose distribution of two other radionuclides. The ability of this model to quantify the absorbed dose and dose response in different intratumoral regions allows one to investigate how source deposition in different tumor areas can affect dose and cytotoxicity, as well as how characteristics of the

  9. 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

  10. Modeling and dosimetric performance evaluation of the RayStation treatment planning system

    Science.gov (United States)

    Mugabe, Koki V.; Sims, Rick; Godwin, Guy; Loria, Dayan

    2014-01-01

    The physics modeling, dose calculation accuracy and plan quality assessment of the RayStation (v3.5) treatment planning system (TPS) is presented in this study, with appropriate comparisons to the more established Pinnacle (v9.2) TPS. Modeling and validation for the Elekta MLCi and Agility beam models resulted in a good match to treatment machine‐measured data based on tolerances of 3% for in‐field and out‐of‐field regions, 10% for buildup and penumbral regions, and a gamma 2%/2 mm dose/distance acceptance criteria. TPS commissioning using a wide range of appropriately selected dosimetry equipment, and following published guidelines, established the MLC modeling and dose calculation accuracy to be within standard tolerances for all tests performed. In both homogeneous and heterogeneous mediums, central axis calculations agreed with measurements within 2% for open fields and 3% for wedged fields, and within 4% off‐axis. Treatment plan comparisons for identical clinical goals were made to Pinnacle for the following complex clinical cases: hypofractionated non‐small cell lung carcinoma, head and neck, stereotactic spine, as well as for several standard clinical cases comprising of prostate, brain, and breast plans. DVHs, target, and critical organ doses, as well as measured point doses and gamma indices, applying both local and global (Van Dyk) normalization at 2%/2 mm and 3%/3 mm (10% lower threshold) acceptance criteria for these composite plans were assessed. In addition 3DVH was used to compare the perturbed dose distributions to the TPS 3D dose distributions. For all 32 cases, the patients QA checks showed > 95% of pixels passing 3% global/3 mm gamma. PACS numbers: 87.55kd, 87.55km, 87.55de, 87.55dk PMID:25207563

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

    International Nuclear Information System (INIS)

    Syme, A M; McQuarrie, S A; Middleton, J W; Fallone, B G

    2003-01-01

    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

  12. Consequences of the Chernobyl accident as the basis for development of ecological and dosimetric models

    International Nuclear Information System (INIS)

    Balonov, M.I.

    1993-01-01

    The paper presents the materials of six year dynamic investigation of Cs and Sr radionuclides content in food products and body of inhabitants of contaminated regions of Russia, and of individual external doses of gamma radiation measured within thermoluminescent method. The models of formation of the dose of external gamma radiation and intake of Cs-134, -137 in body of inhabitants of contaminated locality are formed. The transfer factor from soil to vegetation and to food ration of man for Cs-134, 137 decreases with the half-period of 1 to 1.5 years and depends on soil type and agrochemical characteristics. (orig.)

  13. 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...

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

    International Nuclear Information System (INIS)

    Xaplanteris, C. L.; Xaplanteris, L. C.; Leousis, D. P.

    2014-01-01

    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

  15. 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.

  16. 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.

  17. 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) method...

  18. Dosimetric methods for and influence of exposure parameters on the establishment of reference doses in mammography

    NARCIS (Netherlands)

    Zoetelief, J.; Fitzgerald, M.; Leitz, W.; Säbel, M.

    1998-01-01

    For the establishment of reference doses in mammography it is important to apply a dosimetric model relevant for risk assessment. Differences in dosimetric methods applied in mammography are related to the dosemeters used, e.g. thermoluminescent detectors and ionisation chambers, and the dosimetric

  19. Effects of data quality and quantity in systems modelling: a case study

    Science.gov (United States)

    Kikuchi, Shinya; Kronprasert, Nopadon

    2012-10-01

    When constructing a probability distribution from incomplete and imprecise data, the effects of the quantity and the quality of the data are of serious concern in practical applications. Consider a situation when one is building a matrix of a joint probability distribution. For some events, the probabilities are available only approximately, and for the majority of the events they are not available at all. Traditionally, if the known values are exact values, this type of problem is dealt with by maximizing the Shannon entropy of the distribution while using the known values as constraints. In this case, however, the available information is approximate and represented by fuzzy numbers. A multi-objective optimization method is proposed that employs the well-known principles of maximum and minimum uncertainty. In this method, the Shannon entropy is maximized and, in addition, the known elements whose membership grades are as high as possible are searched for. The method is applied to the construction of an origin-destination (O-D) table of a transit from incomplete and imprecise data. The behaviour of the solution with respect to quantity and quality of available data is tested with sensitivity analysis using real-world data of four transit lines. This analysis reveals how changes in the quantity and quality of data affect the acceptable level of an O-D table. Furthermore, the issue of how to combine O-D tables developed on the basis of different sets of approximate values is examined using a method that minimizes the sum of the relative Shannon entropies.

  20. 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...

  1. Experimental determination of the TG-43 dosimetric characteristics of EchoSeedTM model 6733 125I brachytherapy source

    International Nuclear Information System (INIS)

    Meigooni, A.S.; Dini, Sharifeh A.; Sowards, Keith; Hayes, Joshua L.; Al-Otoom, Awni

    2002-01-01

    Recently an improved design of a 125 I brachytherapy source has been introduced for interstitial seed implants, particularly for prostate seed implants. This design improves the in situ ultrasound visualization of the source compared to the conventional seed. In this project, the TG-43 recommended dosimetric characteristics of the new brachytherapy source have been experimentally determined in Solid Water trade mark sign phantom material. The measured dosimetric characteristics of the new source have been compared with data reported in the literature for other source designs. The measured dose rate constant, Λ, in Solid Water was multiplied by 1.05 to extract the dose rate constant in water. The dose rate constant of the new source in water was found to be 0.99±8% cGy h -1 U -1 . The radial dose function was measured at distances between 0.5 and 10 cm using LiF TLDs in Solid Water trade mark sign phantom. The anisotropy function, F(r,θ), was measured at distances of 2, 3, 5, and 7 cm

  2. 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.

  3. 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.

  4. Estimation of pharmaceutical residues in primary and secondary sewage sludge based on quantities of use and fugacity modelling.

    Science.gov (United States)

    Khan, S J; Ongerth, J E

    2002-01-01

    A general procedure was developed for estimating the concentrations of pharmaceutical residues in fresh primary and secondary sewage sludge. Prescribed quantities coupled with information on the various excretion ratios of 20 pharmaceuticals and 2 of their metabolites enabled prediction of the overall rates of excretion into Australian sewage. Fugacity modelling was applied to predict concentrations of these residues in fresh primary and secondary sludge. Predicted concentrations ranged from 10(-3)-884 microg/L in primary sludge and 10(-4)-36 microg/L in secondary sludge. Overall rates of removal to sludges ranged from 1-39%. The accuracy of the model was verified by comparison to analytical data.

  5. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Stochastic Models of Macroscale Quantities for the Prediction of the REV Scale for Multiphase Flow through Porous Media

    Science.gov (United States)

    Talbot, C.; McClure, J. E.; Armstrong, R. T.; Mostaghimi, P.; Hu, Y.; Miller, C. T.

    2017-12-01

    Microscale experimental and computational methods can be used to evaluate fundamental microscale mechanisms and deduce macroscale constitutive relationships and parameter values. The link between the microscale and the macroscale is especially demanding, because technical issues arise regarding the necessary scale of the system needed for a meaningful set of macroscale measures to be insensitive to the size of the system, which is known as a representative elementary volume (REV). While the REV scale is routinely determined for single-phase flow in porous media, no systematic study of the scale of a REV for the comprehensive set of macroscale measures considered here has been reported in the literature. A comprehensive set of measures of the macroscale state is developed. We further develop and apply methods to predict the REV scale and quantify the uncertainty of the estimate for this set of macroscale quantities. We model the system state in terms of standard errors of macroscale quantities as a multivariate Gaussian process dependent on the size of the domain simulated. We determine predictive distributions of function values and a posterior distributions of weights using standard kernels, as well as a kernel constructed using relationships between physical quantities. For each kernel, we discuss the decay of the mean and covariance with increasing domain size, and use cross-validation to facilitate model selection. The procedure yields a model of the domain size needed to achieve a REV with quantifiable uncertainty. We present results in the context of multiphase fluid flow through a highly resolved realization of sandstone imaged using micro-CT. A 1440x1440x4320 section of the full 2520x2520x5280 imaged medium is simulated using the lattice-Boltzmann method. We compare the fidelity of the predictive model with results obtained by an analogous approach using polynomial regression.

  7. Calibration of uncertain inputs to computer models using experimentally measured quantities and the BMARS emulator

    International Nuclear Information System (INIS)

    Stripling, H.F.; McClarren, R.G.; Kuranz, C.C.; Grosskopf, M.J.; Rutter, E.; Torralva, B.R.

    2011-01-01

    We present a method for calibrating the uncertain inputs to a computer model using available experimental data. The goal of the procedure is to produce posterior distributions of the uncertain inputs such that when samples from the posteriors are used as inputs to future model runs, the model is more likely to replicate (or predict) the experimental response. The calibration is performed by sampling the space of the uncertain inputs, using the computer model (or, more likely, an emulator for the computer model) to assign weights to the samples, and applying the weights to produce the posterior distributions and generate predictions of new experiments within confidence bounds. The method is similar to the Markov chain Monte Carlo (MCMC) calibration methods with independent sampling with the exception that we generate samples beforehand and replace the candidate acceptance routine with a weighting scheme. We apply our method to the calibration of a Hyades 2D model of laser energy deposition in beryllium. We employ a Bayesian Multivariate Adaptive Regression Splines (BMARS) emulator as a surrogate for Hyades 2D. We treat a range of uncertainties in our system, including uncertainties in the experimental inputs, experimental measurement error, and systematic experimental timing errors. The results of the calibration are posterior distributions that both agree with intuition and improve the accuracy and decrease the uncertainty in experimental predictions. (author)

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

    Science.gov (United States)

    Intharathirat, Rotchana; Abdul Salam, P; Kumar, S; Untong, Akarapong

    2015-05-01

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Modelling of pharmaceutical residues in Australian sewage by quantities of use and fugacity calculations.

    Science.gov (United States)

    Khan, Stuart J; Ongerth, Jerry E

    2004-01-01

    A conceptual model is presented for determining which currently prescribed pharmaceutical compounds are most likely to be found in sewage, and for estimating their concentrations, both in raw sewage and after successive stages of secondary sewage treatment. A ranking of the "top-50" pharmaceutical compounds (by total mass dispensed) in Australia over the 1998 calendar year was prepared. Information on the excretion ratios and some metabolites of the pharmaceuticals enabled prediction of the overall rates of excretion into Australian sewage. Mass-balance and fugacity modelling, applied to sewage generation and to a sewage treatment plant, allowed calculation of predicted concentrations of the compounds in raw, primary and secondary treated sewage effluents. Twenty nine of the modelled pharmaceutical residuals were predicted to be present in raw sewage influent at concentrations of 1 microgl(-1) or greater. Twenty of the compounds were predicted to remain in secondary effluent at concentrations of 1 microgl(-1) or greater.

  10. 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...... to explore the relationship. Copyright (C) 1998 IFAC....

  11. Dosimetric comparison of the specific anthropomorphic mannequin (SAM) to 14 anatomical head models using a novel definition for the mobile phone positioning

    International Nuclear Information System (INIS)

    Kainz, Wolfgang; Christ, Andreas; Kellom, Tocher; Seidman, Seth; Nikoloski, Neviana; Beard, Brian; Kuster, Niels

    2005-01-01

    This paper presents new definitions for obtaining reproducible results in numerical phone dosimetry. Numerous numerical dosimetric studies have been published about the exposure of mobile phone users which concluded with conflicting results. However, many of these studies lack reproducibility due to shortcomings in the description of the phone positioning. The new approach was tested by two groups applying two different numerical program packages to compare the specific anthropomorphic mannequin (SAM) to 14 anatomically correct head models. A novel definition for the positioning of mobile phones next to anatomically correct head models is given along with other essential parameters to be reported. The definition is solely based on anatomical characteristics of the head. A simple up-to-date phone model was used to determine the peak spatial specific absorption rate (SAR) of mobile phones in SAM and in the anatomically correct head models. The results were validated by measurements. The study clearly shows that SAM gives a conservative estimate of the exposure in anatomically correct head models for head only tissue. Depending on frequency, phone position and head size the numerically calculated 10 g averaged SAR in the pinna can be up to 2.1 times greater than the peak spatial SAR in SAM. Measurements in small structures, such as the pinna, will significantly increase the uncertainty; therefore SAM was designed for SAR assessment in the head only. Whether SAM will provide a conservative value for the pinna depends on the pinna SAR limit of the safety standard considered

  12. 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.

  13. 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...

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

    International Nuclear Information System (INIS)

    Melandri, C.; Battisti, P.; Tarroni, G.

    1991-02-01

    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 f and slow-clearing thoracic T 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 calculating radiation doses to tissues of the respiratory system following inhalation of α, β and γ emitting particulate and gaseous radionuclides. (author)

  15. Biodistribution dosimetric study of radiopharmaceutical 99mTc Ixolaris in mice for melanoma diagnosis by molecular image and translational model for human beings

    International Nuclear Information System (INIS)

    Soriano, Sarah Canuto Silva

    2015-01-01

    The labeling of Ixolaris with 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 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 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 99m Tc, a range of effective

  16. MO-G-17A-04: Internal Dosimetric Calculations for Pediatric Nuclear Imaging Applications, Using Monte Carlo Simulations and High-Resolution Pediatric Computational Models

    Energy Technology Data Exchange (ETDEWEB)

    Papadimitroulas, P; Kagadis, GC [University of Patras, Rion, Ahaia (Greece); Loudos, G [Technical Educational Institute of Athens, Aigaleo, Attiki (Greece)

    2014-06-15

    Purpose: Our purpose is to evaluate the administered absorbed dose in pediatric, nuclear imaging studies. Monte Carlo simulations with the incorporation of pediatric computational models can serve as reference for the accurate determination of absorbed dose. The procedure of the calculated dosimetric factors is described, while a dataset of reference doses is created. Methods: Realistic simulations were executed using the GATE toolkit and a series of pediatric computational models, developed by the “IT'IS Foundation”. The series of the phantoms used in our work includes 6 models in the range of 5–14 years old (3 boys and 3 girls). Pre-processing techniques were applied to the images, to incorporate the phantoms in GATE simulations. The resolution of the phantoms was set to 2 mm3. The most important organ densities were simulated according to the GATE “Materials Database”. Several used radiopharmaceuticals in SPECT and PET applications are being tested, following the EANM pediatric dosage protocol. The biodistributions of the several isotopes used as activity maps in the simulations, were derived by the literature. Results: Initial results of absorbed dose per organ (mGy) are presented in a 5 years old girl from the whole body exposure to 99mTc - SestaMIBI, 30 minutes after administration. Heart, kidney, liver, ovary, pancreas and brain are the most critical organs, in which the S-factors are calculated. The statistical uncertainty in the simulation procedure was kept lower than 5%. The Sfactors for each target organ are calculated in Gy/(MBq*sec) with highest dose being absorbed in kidneys and pancreas (9.29*10{sup 10} and 0.15*10{sup 10} respectively). Conclusion: An approach for the accurate dosimetry on pediatric models is presented, creating a reference dosage dataset for several radionuclides in children computational models with the advantages of MC techniques. Our study is ongoing, extending our investigation to other reference models and

  17. Dosimetric considerations and radiation protection of patients in interventional cardiology

    International Nuclear Information System (INIS)

    Ciraj-Bjelac, O.; Arandjic, D.; Kosutic, D.; Loncar, B.

    2009-01-01

    The paper summarizes results of measurements of relevant dosimetric quantities in interventional cardiology. Dosimetric data were collected for 117 coronary angiography (CA) procedures, 69 percutaneous coronary interventions (PCI) and 41 combined procedures (CA+PCI), taking into account two quantities: air kerma area product (KAP) d air kerma in international reference point (K IRP ). Mean KAP values were 78 Gy·cm 2 , 113 Gy·cm 2 and 141 Gy·cm 2 for CA, PCI i CA+PCI, respectively. Corresponding mean K IRP values were 1.2 Gy, 1.8 Gy and 2.2 Gy. With respect to high dose values, risk for stochastic effects and tissue reactions, dose management methods were proposed. (author) [sr

  18. Dosimetric investigations in mammography

    International Nuclear Information System (INIS)

    Metges, P.J.; Lorrain, S.

    1981-01-01

    The development film-screen detectors in radiological equipment has led us to study how to improve standard mammographic pictures (focus 0.3 x 0.3 mm, focus-film distance: 65) of thick and dense breasts by the use of an anti-scatter grid and by magnification. A dosimetric study was necessary to assess the doses delivered during mammographic examinations carried out according to various procedures. The results led to modify breast examination procedures and use an anti-scatter grid for breasts thicker than 4 cm or known as dense. The dose increase due to a better quality image is the lowest provided depth penetration is increased by 2 kV as compared to a standard picture. Absorbed doses on the X-ray axis, at 3 cm depth, are below 0.1 rad [fr

  19. Effects of Land Cover Changes to the Quantity of Water Supply and Hydrologic Cycle using Water Balance Models

    Directory of Open Access Journals (Sweden)

    Caja CC

    2018-01-01

    Full Text Available The hydrologic cycle is a recurring consequence of different forms of movement of water and changes of its physical state on a given area of the earth. The land cover of a certain area is a significant factor affecting the watershed hydrology. This also affects the quantity of water supply within the watershed. This study assessed the impacts of the changing land cover of the Ipo watershed, a part of the Angat-Ipo-La Mesa water system which is the main source of Metro Manila’s water supply. The environmental impacts were assessed using the interaction of vegetation cover changes and the output flow rates in Ipo watershed. Using hydrologic modelling system, the hydrological balance using rainfall, vegetation and terrain data of the watershed was simulated. Over the years, there has been a decreasing land cover within the watershed caused mostly by deforestation and other human activities. This significant change in the land cover resulted to extreme increase in water discharge at all streams and rivers in the watershed and the water balance of the area were affected as saturation and shape of the land terrain changes.

  20. Dosimetric adjustment factors for methyl methacrylate derived from a steady-state analysis of a physiologically based clearance-extraction model.

    Science.gov (United States)

    Andersen, M E; Sarangapani, R; Frederick, C B; Kimbell, J S

    1999-10-01

    Cells within the epithelial lining of the nasal cavity metabolize a variety of low-molecular-weight, volatile xenobiotics. In common with terminology developed for other metabolizing organs, the nose extracts these chemicals from the airstream, thereby clearing some portion of the total nasal airflow. In this article, a physiologically based clearance-extraction (PBCE) model of nasal metabolism is used to predict extraction for steady-state conditions. This model, developed by simplification of existing physiologically based pharmacokinetic (PBPK) nasal models, has three tissue regions in two flow paths. A dorsal flow stream sequentially passes over a small area of respiratory epithelium and then over the entire olfactory epithelial surface within the nose. A ventral airstream, consisting of most of the total flow, passes over the larger portion (>80%) of the respiratory epithelium. Each underlying tissue stack has a mucus layer, an epithelial tissue compartment, and a blood exchange region. Metabolism may occur in any of the subcompartments within the tissue stacks. The model, solved directly for a steady-state condition, specifies the volumetric airflow over each stack. Computational fluid dynamic (CFD) solutions for the rat and human for the case with no liquid-phase resistance provided a maximum value for regional extraction, E(max)'. Equivalent air-to-liquid phase permeation coefficients (also referred to as the air-phase mass transfer coefficient) were calculated based on these E(max)' values. The PBCE model was applied to assess expected species differences in nasal extraction and in localized tissue metabolism of methyl methacrylate (MMA) in rats and in humans. Model estimates of tissue dose of MMA metabolites (in micromol metabolized/h/ml tissue) in both species were used to evaluate the dosimetric adjustment factor (DAF) that should be applied in reference concentration (RfC) calculations for MMA. For human ventilation rates equivalent to light exercise

  1. SU-E-T-360: End-To-End Dosimetric Testing of a Versa HD Linear Accelerator with the Agility Head Modeled in Pinnacle3

    Energy Technology Data Exchange (ETDEWEB)

    Saenz, D; Narayanasamy, G; Cruz, W; Papanikolaou, N; Stathakis, S [University of Texas Health Science Center at San Antonio, San Antonio, TX (United States)

    2015-06-15

    Purpose: The Versa HD incorporates a variety of upgrades, primarily including the Agility head. The distinct dosimetric properties of the head from its predecessors combined with flattening-filter-free (FFF) beams require a new investigation of modeling in planning systems and verification of modeling accuracy. Methods: A model was created in Pinnacle{sup 3} v9.8 with commissioned beam data. Leaf transmission was modeled as <0.5% with maximum leaf speed of 3 cm/s. Photon spectra were tuned for FFF beams, for which profiles were modeled with arbitrary profiles rather than with cones. For verification, a variety of plans with varied parameters were devised, and point dose measurements were compared to calculated values. A phantom of several plastic water and Styrofoam slabs was scanned and imported into Pinnacle{sup 3}. Beams of different field sizes, SSD, wedges, and gantry angles were created. All available photon energies (6 MV, 10 MV, 18 MV, 6 FFF, 10 FFF) as well four clinical electron energies (6, 9, 12, and 15 MeV) were investigated. The plans were verified at a calculation point (8 cm deep for photons, variable for electrons) by measurement with a PTW Semiflex ionization chamber. In addition, IMRT testing was performed with three standard plans (step and shoot IMRT, small and large field VMAT plans). The plans were delivered on the Delta4 IMRT QA phantom (ScandiDos, Uppsala, Sweden). Results: Homogeneous point dose measurement agreed within 2% for all photon and electron beams. Open field photon measurements along the central axis at 100 cm SSD passed within 1%. Gamma passing rates were >99.5% for all plans with a 3%/3mm tolerance criteria. The IMRT QA results for the first 23 patients yielded gamma passing rates of 97.4±2.3%. Conclusion: The end-to-end testing ensured confidence in the ability of Pinnacle{sup 3} to model photon and electron beams with the Agility head.

  2. 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...

  3. The Virtual Family-development of surface-based anatomical models of two adults and two children for dosimetric simulations

    Energy Technology Data Exchange (ETDEWEB)

    Christ, Andreas; Honegger, Katharina; Zefferer, Marcel; Neufeld, Esra; Oberle, Michael; Szczerba, Dominik; Kuster, Niels [Foundation for Research on Information Technologies in Society (IT' IS), Zeughausstr. 43, 8004 Zuerich (Switzerland); Kainz, Wolfgang; Guag, Joshua W [US Food and Drug Administration (FDA), Center for Devices and Radiological Health (CDRH), Silver Spring, MD 20993 (United States); Hahn, Eckhart G; Rascher, Wolfgang; Janka, Rolf; Bautz, Werner [Universitaetsklinikum Erlangen, Friedrich-Alexander Universitaet Erlangen-Nuernberg, 91054 Erlangen (Germany); Chen, Ji; Shen, Jianxiang [Department of Electrical and Computer Engineering, The University of Houston, Houston, TX 77204 (United States); Kiefer, Berthold; Schmitt, Peter; Hollenbach, Hans-Peter [Siemens Healthcare, MR-Application Development, 91052 Erlangen (Germany); Kam, Anthony [Department of Imaging, Johns Hopkins Bayview Medical Center, Baltimore, MD 21224 (United States)], E-mail: christ@itis.ethz.ch

    2010-01-21

    The objective of this study was to develop anatomically correct whole body human models of an adult male (34 years old), an adult female (26 years old) and two children (an 11-year-old girl and a six-year-old boy) for the optimized evaluation of electromagnetic exposure. These four models are referred to as the Virtual Family. They are based on high resolution magnetic resonance (MR) images of healthy volunteers. More than 80 different tissue types were distinguished during the segmentation. To improve the accuracy and the effectiveness of the segmentation, a novel semi-automated tool was used to analyze and segment the data. All tissues and organs were reconstructed as three-dimensional (3D) unstructured triangulated surface objects, yielding high precision images of individual features of the body. This greatly enhances the meshing flexibility and the accuracy with respect to thin tissue layers and small organs in comparison with the traditional voxel-based representation of anatomical models. Conformal computational techniques were also applied. The techniques and tools developed in this study can be used to more effectively develop future models and further improve the accuracy of the models for various applications. For research purposes, the four models are provided for free to the scientific community. (note)

  4. The Virtual Family-development of surface-based anatomical models of two adults and two children for dosimetric simulations

    International Nuclear Information System (INIS)

    Christ, Andreas; Honegger, Katharina; Zefferer, Marcel; Neufeld, Esra; Oberle, Michael; Szczerba, Dominik; Kuster, Niels; Kainz, Wolfgang; Guag, Joshua W; Hahn, Eckhart G; Rascher, Wolfgang; Janka, Rolf; Bautz, Werner; Chen, Ji; Shen, Jianxiang; Kiefer, Berthold; Schmitt, Peter; Hollenbach, Hans-Peter; Kam, Anthony

    2010-01-01

    The objective of this study was to develop anatomically correct whole body human models of an adult male (34 years old), an adult female (26 years old) and two children (an 11-year-old girl and a six-year-old boy) for the optimized evaluation of electromagnetic exposure. These four models are referred to as the Virtual Family. They are based on high resolution magnetic resonance (MR) images of healthy volunteers. More than 80 different tissue types were distinguished during the segmentation. To improve the accuracy and the effectiveness of the segmentation, a novel semi-automated tool was used to analyze and segment the data. All tissues and organs were reconstructed as three-dimensional (3D) unstructured triangulated surface objects, yielding high precision images of individual features of the body. This greatly enhances the meshing flexibility and the accuracy with respect to thin tissue layers and small organs in comparison with the traditional voxel-based representation of anatomical models. Conformal computational techniques were also applied. The techniques and tools developed in this study can be used to more effectively develop future models and further improve the accuracy of the models for various applications. For research purposes, the four models are provided for free to the scientific community. (note)

  5. HUMTRN and EFFECTS: Age and sex specific dosimetric and physiological human population dynamics models for dose assessment

    International Nuclear Information System (INIS)

    Gallegos, A.F.; Wenzel, W.J.

    1989-01-01

    A human simulation model called HUMTRN and a population risk assessment model called EFFECTS were developed at Los Alamos National Laboratory as a major component of the BIOTRAN environmental risk assessment model. HUMTRN simulates growth using dietary and physiological characteristics and kinetics of radionuclides to predict radiation doses to selected organs of both sexes in different age groups. The model called EFFECTS was interfaced with output from HUMTRN to predict cancer risks in a dynamic human population. EFFECTS is based on the National Research Council Committee on the Biological Effects of Ionizing Radiation (BEIR)-III radiation cancer mortality estimates from the U.S. population mortality and natality estimates for both sexes between the ages of 1 and 70. These models track radiation intake from air, water, and food, calculate uptake in major growing organs, and estimate cancer mortality risks. This report documents the use of an IBM Personal Computer AT to run HUMTRN and EFFECTS. Air, water, and food contaminant concentrations are provided as input to HUMTRN, which then provides input for EFFECTS. The limitations of this approach are also discussed

  6. Study of the dosimetric response of Gallium Nitride (GaN): modeling, simulation and characterization on radiotherapy

    International Nuclear Information System (INIS)

    Wang, Ruoxi

    2015-01-01

    The work in this thesis has the objective to increase the measurement precision of the dosimetry based on the Gallium Nitride (GaN) transducer and develop its applications on radiotherapy. The study includes the aspects of modeling, simulation and characterization of this response in external radiotherapy and brachytherapy. In modeling, we have proposed two approaches to model the GaN transducer's response in external radiotherapy. For the first approach, a model has been built based on experimental data, while separating the primary and scattering component of the beam. For the second approach, we have adopted a response model initially developed for the silicon diodes for the GaN radioluminescent transducer. We have also proposed an original concept of bi-media dosimetry which evaluates the dose in tissue according to different responses from two media without prior information on the conditions of irradiation. This concept has been shown by Monte Carlo simulation. Moreover, for High Dose Rate brachytherapy, the response of GaN transducer irradiated by iridium 192 and cobalt 60 sources has been evaluated by Monte Carlo simulation and confirmed by the measurements. Studies on the property characterization of GaN radioluminescent transducer has been carried out with these sources as well. An instrumented phantom prototype with GaN probe has been developed for the HDR brachytherapy quality control. It allows a real-time verification of the physics parameters of a treatment (source dwell position, source dwell time, source activity). (author) [fr

  7. 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.

  8. 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

  9. Analysis of the main dosimetric peak of Al2O3:C compounds with a model of interacting traps

    International Nuclear Information System (INIS)

    Ortega, F.; Marcazzó, J.; Molina, P.; Santiago, M.; Lester, M.; Henniger, J.; Caselli, E.

    2013-01-01

    The glow curve of Al 2 O 3 :C compounds has been analyzed by employing a model consisting of two active traps, thermally disconnected traps and one recombination centre. The analysis takes into account interaction among traps and the thermal quenching of the thermoluminescent emission. - Highlights: • Glow curves of Al 2 O 3 :C for two doses have been analysed taking into account interactions among traps. • The system of differential equations describing the kinetics has been uncoupled. • The new system of equations takes into account equations without derivatives. • The algorithm used will not become stiff. • The kinetics parameters obtained do not depend on the dose

  10. 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.

  11. Dosimetric essay in dental radiology

    International Nuclear Information System (INIS)

    Lopez Salaberry, M.

    1998-01-01

    A neck study was observated in the tiroids glands,laryngeal zone, sensitive organs for the ionizing radiation for increase dental xray exams. Was selected 29th patients with radiography prescription complete (in the Odontology Faculty Clinics Uruguaian). It took radiographies with and without tiroids necklace and apron lead using dosemeters. Dosimetric studies had demonstrated good dose between patients. For measuring the radiation dose have been used TLD thermoluminescence dosimetric and Harshaw 6600 for read it. The thyroids necklace use and odontology postgrading for training course for dentistry was the two recommendations advised

  12. The dosimetric control in radiotherapy

    International Nuclear Information System (INIS)

    Veres, A.

    2009-01-01

    The author first presents the thermoluminescent dosimetry method developed by the Equal-Estro Laboratory to control radiotherapy systems, according to which dosimeters are mailed by the radiotherapy centres to the laboratory, and then analyzed with respect to the level of dose bias. In a second part, he discusses the different techniques used for the dosimetric control of new radiotherapy methods (intensity-modulated radiation therapy, tomo-therapy) for which film dosimetry is applied. He also evokes the development of new phantoms and the development of a method for the dosimetric control of proton beams

  13. Modeling of the response under radiation of electronic dosemeters; Modelisations de la reponse sous rayonnements de dosimetres electroniques

    Energy Technology Data Exchange (ETDEWEB)

    Menard, S. [Institut de Radioprotection et de Surete Nucleaire (IRSN), 92 - Fontenay-aux-Roses (France)

    2003-07-01

    The simulation with with calculation codes the interactions and the transport of primary and secondary radiations in the detectors allows to reduce the number of developed prototypes and the number of experiments under radiation. The simulation makes possible the determination of the response of the instrument for exposure configurations more extended that these ones of references radiations produced in laboratories. The M.C.N.P.X. allows to transport, over the photons, electrons and neutrons, the charged particles heavier than the electrons and to simulate the radiation - matter interactions for a certain number of particles. The present paper aims to present the interest of the use of the M.C.N.P.X. code in the study, research and evaluation phases of the instrumentation necessary to the dosimetry monitoring. To do that the presentation gives the results of the modeling of a prototype of a equivalent tissue proportional counter (C.P.E.T.) and of the C.R.A.M.A.L. ( radiation protection apparatus marketed by the Eurisys Mesures society). (N.C.)

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

    International Nuclear Information System (INIS)

    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.

    2013-01-01

    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)

  15. Construction of a computational exposure model for dosimetric calculations using the EGS4 Monte Carlo code and voxel phantoms

    International Nuclear Information System (INIS)

    Vieira, Jose Wilson

    2004-07-01

    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)

  16. 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.

  17. Dangerous quantities of radioactive material (D-values)

    International Nuclear Information System (INIS)

    2010-01-01

    Radioactive material is widely used in industry, medicine, education and agriculture. In addition, it occurs naturally. The health risk posed by these materials vary widely depending on many factors, the most important of which are the amount of the material involved and its physical and chemical form. Therefore, there is a need to identify the quantity and type of radioactive material for which emergency preparedness and other arrangements (e.g. security) are warrant due to the health risk they pose. The aim of this publication is to provide practical guidance for Member States on that quantity of radioactive material that may be considered dangerous. A dangerous quantity is that, which if uncontrolled, could be involved in a reasonable scenario resulting in the death of an exposed individual or a permanent injury, which decreases that person's quality of life. This publication is published as part of the IAEA Emergency Preparedness and Response Series. It supports several publications including: the IAEA Safety Requirements 'Preparedness and Response for a Nuclear or Radiological Emergency', IAEA Safety Standards Series No. GS-R-2. IAEA, Vienna (2002). IAEA Safety Guide 'Categorization of Radioactive Sources', IAEA Safety Standards Series No RS-G-1.9, IAEA, Vienna (2005) and IAEA Safety Guide 'Arrangements for Preparedness for a Nuclear or Radiological Emergency' IAEA Safety Standards Series No. GS-G-2.1, IAEA, Vienna (2006). The procedures and data in this publication have been prepared with due attention to accuracy. However, as part of the review process, they undergo ongoing quality assurance checks. Comments are welcome and, following a period that will allow for a more extensive review, the IAEA may revise this publication as part of the process of continuous improvement. The publication uses a number of exposure scenarios, risk models and dosimetric data, which could be used during the response to nuclear or radiological emergency or other purposes

  18. Toward a nomenclature and dosimetric scheme applicable to all radiations

    International Nuclear Information System (INIS)

    Rupert, C.S.; Latarjet, R.

    1978-01-01

    An informal Joint Working Group on Radiation Quantities, consisting of representatives of the ICRU and other international organizations was initiated at the International Congress of Radiation Research in 1974. The conclusions of a meeting of the Group held in 1975 are summarised. Quantities are proposed to describe any type of radiation field in terms of the total amount of energy carried by the radiation and its distribution with respect to time, area, volume and solid angle, expressed in terms of either radiant energy (joules) or number of particles. If this general approach is agreed to by the parent organizations and others the Group will go on to recommend quantities to represent the interactions of fields with matter and to provide a dosimetric scheme usable with all types of radiation. (author)

  19. Pricing Policies for Quantity Discounts

    OpenAIRE

    Maqbool Dada; K. N. Srikanth

    1987-01-01

    In this paper we analyze the seller's decision to offer quantity discounts to the buyer. We build on an existing model as follows. We first characterize the range of order sizes and prices which reduce costs for the buyer and seller, and develop related pricing schemes. The model is then extended to allow inventory carrying costs to be a function of price.

  20. I.M.C.R.T. and prostate: dosimetric analysis; R.C.M.I. et prostate: analyse dosimetrique

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, V.; Bourdin, S.; Rio, E.; Mahe, M. [Centre Rene-Gauducheau, Service de Radiotherapie, 44 - Saint-Herblain (France); Munos, C.; Lisbona, A. [Centre Rene-Gauducheau, Service de Physique Medicale, 44 - Saint-Herblain (France); Campion, L. [Centre Rene-Gauducheau, Dept. de Biostatistiques, 44 - Saint-Herblain (France)

    2007-11-15

    From this dosimetric descriptive analysis has been the feasibility of the dosimetric model respecting the criteria of the intensity modulated conformal radiotherapy (I.M.C.R.T.) for the coverage of the target volume and interindividual variability in volumes of the organs at risk. Full data of this continuous surveillance provide us information on the relevance of these dosimetric constraints and the role of the irradiated volume of organs a risk in terms of toxicity and quality of life. (N.C.)

  1. 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.

  2. 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.

  3. 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

    2017-06-01

    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.

  4. 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.

  5. Use of the STORM model for estimating the quantity and quality of runoff from the metropolitan area of Houston, Texas

    Science.gov (United States)

    Waddell, Kidd M.; Massey, Bernard C.; Jennings, Marshall E.

    1979-01-01

    The "STORM" model, developed by the U.S. Army Corps of Engineers, was selected from existing models and adapted to use available data to compute runoff from the Houston, Texas, area and to compute the loads and concentrations of biochemicaloxygen demand, dissolved solids, total phosphorus, total organic carbon, total nitrogen, and fecal-coliform bacteria. The water-quality data simulated by the STORM model will be used by the Texas Department of Water Resources to refine and verify a model of the Calveston Bay estuarine system. 

  6. [Coupling SWAT and CE-QUAL-W2 models to simulate water quantity and quality in Shanmei Reservoir watershed].

    Science.gov (United States)

    Liu, Mei-Bing; Chen, Dong-Ping; Chen, Xing-Wei; Chen, Ying

    2013-12-01

    A coupled watershed-reservoir modeling approach consisting of a watershed distributed model (SWAT) and a two-dimensional laterally averaged model (CE-QUAL-W2) was adopted for simulating the impact of non-point source pollution from upland watershed on water quality of Shanmei Reservoir. Using the daily serial output from Shanmei Reservoir watershed by SWAT as the input to Shanmei Reservoir by CE-QUAL-W2, the coupled modeling was calibrated for runoff and outputs of sediment and pollutant at watershed scale and for elevation, temperature, nitrate, ammonium and total nitrogen in Shanmei Reservoir. The results indicated that the simulated values agreed fairly well with the observed data, although the calculation precision of downstream model would be affected by the accumulative errors generated from the simulation of upland model. The SWAT and CE-QUAL-W2 coupled modeling could be used to assess the hydrodynamic and water quality process in complex watershed comprised of upland watershed and downstream reservoir, and might further provide scientific basis for positioning key pollution source area and controlling the reservoir eutrophication.

  7. A mathematical model to determine incorporated quantities of radioactivity from the measured photometric values of tritium-autoradiographs in neuroanatomy

    International Nuclear Information System (INIS)

    Jennissen, J.J.

    1981-01-01

    The mathematical/empirical model developed in this paper helps to determine the incorporated radioactivity from the measured photometric values and the exposure time T. Possible errors of autoradiography due to the exposure time or the preparation are taken into consideration by the empirical model. It is shown that the error of appr. 400% appearing in the sole comparison of the measured photometric values can be corrected. The model is valid for neuroanatomy as optical nerves, i.e. neuroanatomical material, were used to develop it. Its application also to the other sections of the central nervous system seems to be justified due to the reduction of errors thus achieved. (orig.) [de

  8. Paying for quality not quantity: a wisconsin health maintenance organization proposes an incentive model for reimbursement of chiropractic services.

    Science.gov (United States)

    Pursel, Kevin J; Jacobson, Martin; Stephenson, Kathy

    2012-07-01

    The purpose of this study is to describe a reimbursement model that was developed by one Health Maintenance Organization (HMO) to transition from fee-for-service to add a combination of pay for performance and reporting model of reimbursement for chiropractic care. The previous incentive program used by the HMO provided best-practice education and additional reimbursement incentives for achieving the National Committee for Quality Assurance Back Pain Recognition Program (NCQA-BPRP) recognition status. However, this model had not leveled costs between doctors of chiropractic (DCs). Therefore, the HMO management aimed to develop a reimbursement model to incentivize providers to embrace existing best-practice models and report existing quality metrics. The development goals included the following: it should (1) be as financially predictable as the previous system, (2) cost no more on a per-member basis, (3) meet the coverage needs of its members, and (4) be able to be operationalized. The model should also reward DCs who embraced best practices with compensation, not simply tied to providing more procedures, the new program needed to (1) cause little or no disruption in current billing, (2) be grounded achievable and defined expectations for improvement in quality, and (3) be voluntary, without being unduly punitive, should the DC choose not to participate in the program. The generated model was named the Comprehensive Chiropractic Quality Reimbursement Methodology (CCQRM; pronounced "Quorum"). In this hybrid model, additional reimbursement, beyond pay-for-procedures will be based on unique payment interpretations reporting selected, existing Physician Quality Reporting System (PQRS) codes, meaningful use of electronic health records, and achieving NCQA-BPRP recognition. This model aims to compensate providers using pay-for-performance, pay-for-quality reporting, pay-for-procedure methods. The CCQRM reimbursement model was developed to address the current needs of one

  9. Thermodynamic modeling of the Ca-Sn system based on finite temperature quantities from first-principles and experiment

    International Nuclear Information System (INIS)

    Ohno, M.; Kozlov, A.; Arroyave, R.; Liu, Z.K.; Schmid-Fetzer, R.

    2006-01-01

    The thermodynamic model of the Ca-Sn system was obtained, utilizing the first-principles total energies and heat capacities calculated from 0 K to the melting points of the major phases. Since the first-principles result for the formation energy of the dominating Ca 2 Sn intermetallic phase is drastically different from the reported experimental data, we performed two types of thermodynamic modeling: one based on the first-principles output and the other based on the experimental data. In the former modeling, the Gibbs energies of the intermetallic compounds were fully quantified from the first-principles finite temperature properties and the superiority of the former thermodynamic description is demonstrated. It is shown that it is the combination of finite temperature first-principle calculations and the Calphad modeling tool that provides a sound basis for identifying and deciding on conflicting key thermodynamic data in the Ca-Sn system

  10. Quantities for environmental monitoring

    International Nuclear Information System (INIS)

    1989-01-01

    It is recommended that if measurements are made with the objective of monitor radiation levels in the environment to elucidate long-term changes in these levels, then air kerma should be used. If the objective is to give an indication that levels from man-made sources are acceptable within specified limits for the exposure of people, then ambient dose equivalent should be used. It should be noted that radiation risks to individuals are best expressed by the quantity effective dose equivalent. If this latter quantity is to be accurately assessed, it may be necessary to obtain details of the quality of the environmental radiation that cannot be described adequately by simple measurements of either air kerma or ambient dose equivalent. If the above objectives pertain, the measurements should record both air kerma and ambient dose equivalent. If neutrons are measured in the environment then ambient dose equivalent is the appropriate quantity for both the above objectives. (author)

  11. THE EVOLUTION OF ANNUAL MEAN TEMPERATURE AND PRECIPITATION QUANTITY VARIABILITY BASED ON ESTIMATED CHANGES BY THE REGIONAL CLIMATIC MODELS

    Directory of Open Access Journals (Sweden)

    Paula Furtună

    2013-03-01

    Full Text Available Climatic changes are representing one of the major challenges of our century, these being forcasted according to climate scenarios and models, which represent plausible and concrete images of future climatic conditions. The results of climate models comparison regarding future water resources and temperature regime trend can become a useful instrument for decision makers in choosing the most effective decisions regarding economic, social and ecologic levels. The aim of this article is the analysis of temperature and pluviometric variability at the closest grid point to Cluj-Napoca, based on data provided by six different regional climate models (RCMs. Analysed on 30 year periods (2001-2030,2031-2060 and 2061-2090, the mean temperature has an ascending general trend, with great varability between periods. The precipitation expressed trough percentage deviation shows a descending general trend, which is more emphazied during 2031-2060 and 2061-2090.

  12. Dosimetric methodology of the ICRP

    International Nuclear Information System (INIS)

    Eckerman, K.F.

    1994-01-01

    Establishment of guidance for the protection of workers and members of the public from radiation exposures necessitates estimation of the radiation dose to tissues of the body at risk. The dosimetric methodology formulated by the International Commission on Radiological Protection (ICRP) is intended to be responsive to this need. While developed for radiation protection, elements of the methodology are often applied in addressing other radiation issues; e.g., risk assessment. This chapter provides an overview of the methodology, discusses its recent extension to age-dependent considerations, and illustrates specific aspects of the methodology through a number of numerical examples

  13. 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.

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

    Science.gov (United States)

    Koch, Josef; 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.

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

    Directory of Open Access Journals (Sweden)

    Josef Koch

    Full Text Available 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.

  16. A national dosimetric audit of IMRT

    International Nuclear Information System (INIS)

    Budgell, Geoff; Berresford, Joe; Trainer, Michael; Bradshaw, Ellie; Sharpe, Peter; Williams, Peter

    2011-01-01

    Background and purpose: A dosimetric audit of IMRT has been carried out within the UK between June 2009 and March 2010 in order to provide an independent check of safe implementation and to identify problems in the modelling and delivery of IMRT. Methods and materials: A mail based audit involving film and alanine dosimeters was utilized. Measurements were made for each individual field in an IMRT plan isocentrically in a flat water-equivalent phantom at a depth of 5 cm. The films and alanine dosimeters were processed and analysed centrally; additional ion chamber measurements were made by each participating centre. Results: 57 of 62 centres participated, with a total of 78 plans submitted. For the film measurements, all 176 fields from the less complex IMRT plans (including prostate and breast plans) achieved over 95% pixels passing a gamma criterion of 3%/3 mm within the 20% isodose. For the more complex IMRT plans (mainly head and neck) 8/245 fields (3.3%) achieved less than 95% pixels passing a 4%/4 mm gamma criterion. Of the alanine measurements, 4/78 (5.1%) of the measurements differed by >5% from the dose predicted by the treatment planning system. Three of these were large deviations of -77.1%, -29.1% and 14.1% respectively. Excluding the three measurements outside 10%, the mean difference was 0.05% with a standard deviation of 1.5%. The out of tolerance results have been subjected to further investigations. Conclusions: A dosimetric audit has been successfully carried out of IMRT implementation by over 90% of UK radiotherapy departments. The audit shows that modelling and delivery of IMRT is accurate, suggesting that the implementation of IMRT has been carried out safely.

  17. Quantities, Units, and Symbols.

    Science.gov (United States)

    Royal Society, London (England).

    This booklet provides a reference to the quantities, units, and their symbols which are used in physical science. It is a revision of a 1969 report and takes account of the progress which has been made in obtaining international agreement on the definitions, names, and symbols for units and on the rules for the expression of relations involving…

  18. Unraveling quantity discounts

    NARCIS (Netherlands)

    Schotanus, Fredo; Telgen, Jan; de Boer, L.

    2009-01-01

    We consider the situation in which a buying organization deals with a discrete quantity discount schedule offered by a selling organization. Furthermore, the buying organization can negotiate with the selling organization about the lot size and purchase price, but does not know the underlying

  19. Dosimetric evaluation of proton stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Min, Byung Jun; Shin, Dong Ho; Yoo, Seung Hoon; Jeong, Hojin; Lee, Se Byeong

    2011-01-01

    Surgical excision, conventional external radiotherapy, and chemotherapy could prolong survival in patients with small intracranial tumors. However, surgical excision for meningiomas located in the region of the base of skull or re-resection is often difficult. Moreover, treatment is needed for patients with recurrent tumors or postoperative residual tumors. Conventional external radiotherapy is popular and has significantly increased for treating brain tumors. Stereotactic radiosurgery is an effective alternative treatment technique to microsurgical resection such as benign brain tumor or vestibular Schwannomas. In general, the dose to OAR of 3D conformal plan is lower than that of conformal arc and dynamic conformal arc plans. However, any of OARs was not reached to tolerance dose. Although mean dose of the healthy brain tissue for 3D conformal plan was slightly higher than that of arc plans, the doses of the healthy brain tissue at V10 and V20 were significantly low for dynamic conformal arc plan. The dosimetric differences were the greatest at lower doses. In contrast, 3D conformal plan was better spare at higher doses. In this study, a dosimetric evaluation of proton stereotactic radiosurgery for brain lesion tumors was using fixed and arc beams. A brass block fitted to the PTV structure was modeled for dynamic conformal collimator. Although all treatment plans offer a very good coverage of the PTV, we found that proton arc plans had significantly better conformity to the PTV than static 3D conformal plan. The V20 dose of normal brain for dynamic conformal arc therapy is dramatically reduced compare to those for other therapy techniques.

  20. NELL-1 Injection Maintains Long-Bone Quantity and Quality in an Ovariectomy-Induced Osteoporotic Senile Rat Model

    Science.gov (United States)

    Kwak, Jinny; Zara, Janette N.; Chiang, Michael; Ngo, Richard; Shen, Jia; James, Aaron W.; Le, Khoi M.; Moon, Crystal; Zhang, Xinli; Gou, Zhongru; Ting, Kang

    2013-01-01

    Over 10 million Americans have osteoporosis, and is the predominant cause of fractures in the elderly. Treatment of fractures in the setting of osteoporosis is complicated by a suboptimal bone regenerative response due to a decline in the number of osteoblasts, their function, and survival. Consequently, an osteogenic therapeutic to prevent and treat fractures in patients with osteoporosis is needed. Nel-like molecule-1 (NELL-1), a novel osteoinductive growth factor, has been shown to promote bone regeneration. In this study, we aim to demonstrate the capacity of recombinant NELL-1 to prevent ovariectomy (OVX)-induced osteoporosis in a senile rat model. Ten-month-old female Sprague-Dawley rats underwent either sham surgery or OVX. Subsequently, 50 μL of 600 μg/mL NELL-1 lyophilized onto a 0–50-μm tricalcium phosphate (TCP) carrier was injected into the femoral bone marrow cavity while phosphate-buffered saline (PBS) control was injected into the contralateral femur. Our microcomputed tomography results showed that OVX+PBS/TCP control femurs showed a continuous decrease in the bone volume (BV) and bone mineral density (BMD) from 2 to 8 weeks post-OVX. In contrast, OVX+NELL-1/TCP femurs showed resistance to OVX-induced bone resorption showing BV and BMD levels similar to that of SHAM femurs at 8 weeks post-OVX. Histology showed increased endosteal-woven bone, as well as decreased adipocytes in the bone marrow of NELL-1-treated femurs compared to control. NELL-1-treated femurs also showed increased immunostaining for bone differentiation markers osteopontin and osteocalcin. These findings were validated in vitro, in which addition of NELL-1 in OVX bone marrow stem cells resulted in increased osteogenic differentiation. Thus, NELL-1 effectively enhances in situ osteogenesis in the bone marrow, making it potentially useful in the prevention and treatment of osteoporotic fractures. PMID:23083222

  1. Dynamic Data-Driven Reduced-Order Models of Macroscale Quantities for the Prediction of Equilibrium System State for Multiphase Porous Medium Systems

    Science.gov (United States)

    Talbot, C.; McClure, J. E.; Armstrong, R. T.; Mostaghimi, P.; Hu, Y.; Miller, C. T.

    2017-12-01

    Microscale simulation of multiphase flow in realistic, highly-resolved porous medium systems of a sufficient size to support macroscale evaluation is computationally demanding. Such approaches can, however, reveal the dynamic, steady, and equilibrium states of a system. We evaluate methods to utilize dynamic data to reduce the cost associated with modeling a steady or equilibrium state. We construct data-driven models using extensions to dynamic mode decomposition (DMD) and its connections to Koopman Operator Theory. DMD and its variants comprise a class of equation-free methods for dimensionality reduction of time-dependent nonlinear dynamical systems. DMD furnishes an explicit reduced representation of system states in terms of spatiotemporally varying modes with time-dependent oscillation frequencies and amplitudes. We use DMD to predict the steady and equilibrium macroscale state of a realistic two-fluid porous medium system imaged using micro-computed tomography (µCT) and simulated using the lattice Boltzmann method (LBM). We apply Koopman DMD to direct numerical simulation data resulting from simulations of multiphase fluid flow through a 1440x1440x4320 section of a full 1600x1600x5280 realization of imaged sandstone. We determine a representative set of system observables via dimensionality reduction techniques including linear and kernel principal component analysis. We demonstrate how this subset of macroscale quantities furnishes a representation of the time-evolution of the system in terms of dynamic modes, and discuss the selection of a subset of DMD modes yielding the optimal reduced model, as well as the time-dependence of the error in the predicted equilibrium value of each macroscale quantity. Finally, we describe how the above procedure, modified to incorporate methods from compressed sensing and random projection techniques, may be used in an online fashion to facilitate adaptive time-stepping and parsimonious storage of system states over time.

  2. IPIP: A new approach to inverse planning for HDR brachytherapy by directly optimizing dosimetric indices

    International Nuclear Information System (INIS)

    Siauw, Timmy; Cunha, Adam; Atamtuerk, Alper; Hsu, I-Chow; Pouliot, Jean; Goldberg, Ken

    2011-01-01

    Purpose: Many planning methods for high dose rate (HDR) brachytherapy require an iterative approach. A set of computational parameters are hypothesized that will give a dose plan that meets dosimetric criteria. A dose plan is computed using these parameters, and if any dosimetric criteria are not met, the process is iterated until a suitable dose plan is found. In this way, the dose distribution is controlled by abstract parameters. The purpose of this study is to develop a new approach for HDR brachytherapy by directly optimizing the dose distribution based on dosimetric criteria. Methods: The authors developed inverse planning by integer program (IPIP), an optimization model for computing HDR brachytherapy dose plans and a fast heuristic for it. They used their heuristic to compute dose plans for 20 anonymized prostate cancer image data sets from patients previously treated at their clinic database. Dosimetry was evaluated and compared to dosimetric criteria. Results: Dose plans computed from IPIP satisfied all given dosimetric criteria for the target and healthy tissue after a single iteration. The average target coverage was 95%. The average computation time for IPIP was 30.1 s on an Intel(R) Core TM 2 Duo CPU 1.67 GHz processor with 3 Gib RAM. Conclusions: IPIP is an HDR brachytherapy planning system that directly incorporates dosimetric criteria. The authors have demonstrated that IPIP has clinically acceptable performance for the prostate cases and dosimetric criteria used in this study, in both dosimetry and runtime. Further study is required to determine if IPIP performs well for a more general group of patients and dosimetric criteria, including other cancer sites such as GYN.

  3. IPIP: A new approach to inverse planning for HDR brachytherapy by directly optimizing dosimetric indices.

    Science.gov (United States)

    Siauw, Timmy; Cunha, Adam; Atamtürk, Alper; Hsu, I-Chow; Pouliot, Jean; Goldberg, Ken

    2011-07-01

    Many planning methods for high dose rate (HDR) brachytherapy require an iterative approach. A set of computational parameters are hypothesized that will give a dose plan that meets dosimetric criteria. A dose plan is computed using these parameters, and if any dosimetric criteria are not met, the process is iterated until a suitable dose plan is found. In this way, the dose distribution is controlled by abstract parameters. The purpose of this study is to develop a new approach for HDR brachytherapy by directly optimizing the dose distribution based on dosimetric criteria. The authors developed inverse planning by integer program (IPIP), an optimization model for computing HDR brachytherapy dose plans and a fast heuristic for it. They used their heuristic to compute dose plans for 20 anonymized prostate cancer image data sets from patients previously treated at their clinic database. Dosimetry was evaluated and compared to dosimetric criteria. Dose plans computed from IPIP satisfied all given dosimetric criteria for the target and healthy tissue after a single iteration. The average target coverage was 95%. The average computation time for IPIP was 30.1 s on an Intel(R) Core 2 Duo CPU 1.67 GHz processor with 3 Gib RAM. IPIP is an HDR brachytherapy planning system that directly incorporates dosimetric criteria. The authors have demonstrated that IPIP has clinically acceptable performance for the prostate cases and dosimetric criteria used in this study, in both dosimetry and runtime. Further study is required to determine if IPIP performs well for a more general group of patients and dosimetric criteria, including other cancer sites such as GYN.

  4. IPIP: A new approach to inverse planning for HDR brachytherapy by directly optimizing dosimetric indices

    Energy Technology Data Exchange (ETDEWEB)

    Siauw, Timmy; Cunha, Adam; Atamtuerk, Alper; Hsu, I-Chow; Pouliot, Jean; Goldberg, Ken [Department of Civil and Environmental Engineering, University of California, Berkeley, 760 Davis Hall, Berkeley, California 94720-1710 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Industrial Engineering and Operations, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Industrial Engineering and Operations Research and Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States)

    2011-07-15

    Purpose: Many planning methods for high dose rate (HDR) brachytherapy require an iterative approach. A set of computational parameters are hypothesized that will give a dose plan that meets dosimetric criteria. A dose plan is computed using these parameters, and if any dosimetric criteria are not met, the process is iterated until a suitable dose plan is found. In this way, the dose distribution is controlled by abstract parameters. The purpose of this study is to develop a new approach for HDR brachytherapy by directly optimizing the dose distribution based on dosimetric criteria. Methods: The authors developed inverse planning by integer program (IPIP), an optimization model for computing HDR brachytherapy dose plans and a fast heuristic for it. They used their heuristic to compute dose plans for 20 anonymized prostate cancer image data sets from patients previously treated at their clinic database. Dosimetry was evaluated and compared to dosimetric criteria. Results: Dose plans computed from IPIP satisfied all given dosimetric criteria for the target and healthy tissue after a single iteration. The average target coverage was 95%. The average computation time for IPIP was 30.1 s on an Intel(R) Core{sup TM}2 Duo CPU 1.67 GHz processor with 3 Gib RAM. Conclusions: IPIP is an HDR brachytherapy planning system that directly incorporates dosimetric criteria. The authors have demonstrated that IPIP has clinically acceptable performance for the prostate cases and dosimetric criteria used in this study, in both dosimetry and runtime. Further study is required to determine if IPIP performs well for a more general group of patients and dosimetric criteria, including other cancer sites such as GYN.

  5. Quality versus Quantity

    Directory of Open Access Journals (Sweden)

    Daniel M. Stamm

    2011-07-01

    Full Text Available This essay compares American and Asian education and illustrates how quantity is chosen over quality in the U.S. in the areas of teacher training, research in education, curriculum and textbook design, and the level of education given highest priority. After demonstrating that Japanese teacher-conducted classroom research (lesson study hasresulted in more practical, higher quality curriculum, textbooks, and teachers’ manuals, it address the objections to the use of those materials in the United States to improve teacher training and student achievement.

  6. DOE approach to threshold quantities

    International Nuclear Information System (INIS)

    Wickham, L.E.; Kluk, A.F.; Department of Energy, Washington, DC)

    1985-01-01

    The Department of Energy (DOE) is developing the concept of threshold quantities for use in determining which waste materials must be handled as radioactive waste and which may be disposed of as nonradioactive waste at its sites. Waste above this concentration level would be managed as radioactive or mixed waste (if hazardous chemicals are present); waste below this level would be handled as sanitary waste. Ideally, the threshold must be set high enough to significantly reduce the amount of waste requiring special handling. It must also be low enough so that waste at the threshold quantity poses a very small health risk and multiple exposures to such waste would still constitute a small health risk. It should also be practical to segregate waste above or below the threshold quantity using available instrumentation. Guidance is being prepared to aid DOE sites in establishing threshold quantity values based on pathways analysis using site-specific parameters (waste stream characteristics, maximum exposed individual, population considerations, and site specific parameters such as rainfall, etc.). A guidance dose of between 0.001 to 1.0 mSv/y (0.1 to 100 mrem/y) was recommended with 0.3 mSv/y (30 mrem/y) selected as the guidance dose upon which to base calculations. Several tasks were identified, beginning with the selection of a suitable pathway model for relating dose to the concentration of radioactivity in the waste. Threshold concentrations corresponding to the guidance dose were determined for waste disposal sites at a selected humid and arid site. Finally, cost-benefit considerations at the example sites were addressed. The results of the various tasks are summarized and the relationship of this effort with related developments at other agencies discussed

  7. Technology development for evaluation of operational quantities in radiation protection

    International Nuclear Information System (INIS)

    Jang, Si Young; Lee, T. Y.; Kim, B. H.

    2003-03-01

    Korean government recently published a national regulation on the internal exposure monitoring and dose evaluation (internal dosimetry) based on the most recent ICRP recommendation 60 and subsequent publications, which supercede the former ICRP recommendation 26 and publication 30, on which the internal dosimetry practice in Korea had been based so far. Consequently, this project, according to the demand from both government and nuclear industry, had been launched to develop a user-friendly computer code on internal dosimetry adopting the most up to date ICRP biokinetic and dosimetric model to resolve the difficulties and problems faced to nuclear industry and to develop related technology. The reliability of this code, named as BiDAS, as a result of several benchmark calculations for self assurance appeared to be excellent comparing with the foreign computer code. This computer code is expected to be successfully utilized in nuclear industry and related fields in complying with the national regulation on internal dosimetry program started from late 2003. Reference low level gamma(γ) radiation field for calibration of environmental radiation(γ) monitor and reference neutron field for calibration of n monitoring equipment have been established and characterized. International cross comparison of these reference radiation fields have been performed and radiation response of various radiation monitoring instrument has been tested by using these reference radiation fields. A technology which can directly measure the radiation quality factor and tissue absorbed dose has been established to evaluate the neutron dose in terms of operational quantity in the unknown mixed n-γ radiation field. Spherical and cylindrical TEPC systems have been designed and manufactured and a portable TEPC system to measure the neutron quality and dose in the real work field has been developed and tested in accelerator laboratory

  8. 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

  9. Allen's astrophysical quantities

    CERN Document Server

    2000-01-01

    This new, fourth, edition of Allen's classic Astrophysical Quantities belongs on every astronomer's bookshelf. It has been thoroughly revised and brought up to date by a team of more than ninety internationally renowned astronomers and astrophysicists. While it follows the basic format of the original, this indispensable reference has grown to more than twice the size of the earlier editions to accommodate the great strides made in astronomy and astrophysics. It includes detailed tables of the most recent data on: - General constants and units - Atoms, molecules, and spectra - Observational astronomy at all wavelengths from radio to gamma-rays, and neutrinos - Planetary astronomy: Earth, planets and satellites, and solar system small bodies - The Sun, normal stars, and stars with special characteristics - Stellar populations - Cataclysmic and symbiotic variables, supernovae - Theoretical stellar evolution - Circumstellar and interstellar material - Star clusters, galaxies, quasars, and active galactic nuclei ...

  10. Measuring Latent Quantities

    Science.gov (United States)

    McDonald, Roderick P.

    2011-01-01

    A distinction is proposed between measures and predictors of latent variables. The discussion addresses the consequences of the distinction for the true-score model, the linear factor model, Structural Equation Models, longitudinal and multilevel models, and item-response models. A distribution-free treatment of calibration and…

  11. Dosimetric studies in diagnostic radiology

    International Nuclear Information System (INIS)

    Mohamadain, K. E. M.

    2004-04-01

    A dosimetric study in pediatric radiology and adult patients was currently being carried out at the pediatrics units of two large hospitals in Rio de Janeiro city: IPPMG (Instituto de Pediatric e Puericultura Martagao Gesteira, University hospital of federal University of Rio de Janeiro), IFF (Instituto Fernandes Figueira, FIOCRUZ) and Hospital Geral de Bonsucesso, a large public hospital in Rio de Janeiro city (HGB) Brazil. The dosimetric study was also performed at three pediatrics units in Sudan, namely, Ahmed Gasim, Khartoum and Omdurman hospitals. For chest x-ray examination the entrance skin dose(ESD) for AP, PA and LAT projections of pediatric patients, and the scattered dose at the thyroid, ovary and gonads have been obtained with thermoluminescent dosimeters (TLD) and with use of a software package Dosecal in thr Brazilian hospitals, and with the software dosecal in the Sudanese hospitals.The aim of this work was to estimate the entrance skin dose (ESD), the effective dose (ED) and the body organ dose (BOD) for chest x-ray exposure in pediatric patients, and different exams for adults patients, and to compare the results obtained in the tow Countries Sudan and Brazil with the reference dose level. For ESD evaluation of the chest x-ray, three different TL dosimeters have been used, namely LiF: Mg, Ti (TLD 100) CaSo 4 : Dy and LiF:Mg, Cu,P (TLD 100 H). The age intervals considered were: 0-1 years, 1-5 years, 5-10 years and 10-15 years. The results obtained with all dosimeters were in good agreement with, those obtained by the dosecal software, especially for AP and PA projection. However, some discrepancies were found for the LAT projection. The results within Brazil were some what consistent while in Sudan, large difference were observed, it was also noted that the doses in Brazil hospitals were less than the reference dose levels while in Sudanese hospitals the doses were higher than the reference dose levels. For adult patients only the software dosecal

  12. Physical Quantities, Measurement Sets, Theories

    Science.gov (United States)

    Viallefond, F.

    2012-09-01

    A methodology is proposed to develop efficient, robust and expressive data models. The idea is to transform objects described using our human language into mathematical objects which can then be used efficiently in information systems. This is done using topological spaces and algebras to model data types. Technically it is implemented using parametric polymorphism. Two examples are shown, 1) a simple well known object, the physical quantities, and 2) a data-base object, the measurement sets which bind the measurements to their experimental contexts. This leads to theories. The result is high expressiveness by formulating equations and data base operations by means of λ calculi. The theory of the measurement set encapsulates the relational model. Using topoi it is a generalization, a category above the sets.

  13. Neutron sources and its dosimetric characteristics

    International Nuclear Information System (INIS)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Mercado S, G.A.; Gallego D, E.; Lorente F, A.

    2005-01-01

    By means of Monte Carlo methods the spectra of the produced neutrons 252 Cf, 252 Cf/D 2 O, 241 Am Be, 239 Pu Be, 140 La Be, 239 Pu 18 O 2 and 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 * (10), H p,sIab (10, 0 0 ), E AP and E 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 239 Pu Be and 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)

  14. Chilean Nuclear Energy Commission dosimetric information system

    International Nuclear Information System (INIS)

    Guerrero Vallejos, Patricia Andrea

    1997-01-01

    This thesis discusses the nuclear radiation that people who work with radioactive material is exposed to and its control by the Chilean Nuclear Energy Commission. A full analysis of the System is presented with information about the Commission and the Department of Nuclear and Radiological Safety which runs the System. Ana analysis of the System is presented in order to obtain requirements. Management flow diagrams, the processes involved and current problems experienced by the users are described. A design logic is modeled producing Data Flow Diagrams (DFD). based on this physical design, or, Model of Physical Data, is prepared including tables, attributes, types of data, primary and foreign keys. A description is presented of how the System is implemented, the tools that are used and how the testing phase is carried out. The Dosimetry System meets the criteria for a Software Engineering project, where the basic cycle was used as a working methodology. The System developed supports the dosimetric control of people exposed to radioactive material. (author)

  15. 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.

  16. Dosimetric approaches: pregnancy and lactation

    International Nuclear Information System (INIS)

    Rojo, Ana M.

    2001-01-01

    The female nuclear medicine patient is of special concern to the evaluation of radiation dose since radiation protection point of view: a)- The females overall body size and organ sizes are generally smaller than those of her male counterpart (thus her radiation doses will be higher, given the same amounts of administered activity and similar biokinetics), the effective doses could be 25 per cent higher than a man; b)- Female gonads are inside the body instead of outside and are near several organs often important as source organs in internal dosimetry; female gonads doses could be up to 10 or 30 higher than male gonads (usually 3 order); c)- Risk of breast cancer is significantly higher among females than males; d)- During the pregnancy due to placental transfer of radiopharmaceuticals or radiation exposure from the urinary bladder the embryo/fetus could receive doses that must be avoid; e)- In the case of nursing infant is of special concern in such an analysis to determine the interruption period to avoid doses in the nursing infant. The dosimetric approaches to take account to assess internal doses in the pregnant woman and during the breast feeding are discussed. (author)

  17. Dosimetric verification of IMRT plans

    International Nuclear Information System (INIS)

    Bulski, W.; Cheimicski, K.; Rostkowska, J.

    2012-01-01

    Intensity modulated radiotherapy (IMRT) is a complex procedure requiring proper dosimetric verification. IMRT dose distributions are characterized by steep dose gradients which enable to spare organs at risk and allow for an escalation of the dose to the tumor. They require large number of radiation beams (sometimes over 10). The fluence measurements for individual beams are not sufficient for evaluation of the total dose distribution and to assure patient safety. The methods used at the Centre of Oncology in Warsaw are presented. In order to measure dose distributions in various cross-sections the film dosimeters were used (radiographic Kodak EDR2 films and radiochromic Gafchromic EBT films). The film characteristics were carefully examined. Several types of tissue equivalent phantoms were developed. A methodology of comparing measured dose distributions against the distributions calculated by treatment planning systems (TPS) was developed and tested. The tolerance level for this comparison was set at 3% difference in dose and 3 mm in distance to agreement. The so called gamma formalism was used. The results of these comparisons for a group of over 600 patients are presented. Agreement was found in 87 % of cases. This film dosimetry methodology was used as a benchmark to test and validate the performance of commercially available 2D and 3D matrices of detectors (ionization chambers or diodes). The results of these validations are also presented. (authors)

  18. 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

  19. Relativity of Electric Quantity

    Directory of Open Access Journals (Sweden)

    GAO Zhong-wen

    2017-04-01

    Full Text Available The demonstration foundation,which is used to demonstrate that observed values from the interaction force between two charges,which are not at the same point would be different in different reference frames,is that the transmission of the interaction between charges needs time. Firstly,this paper analyzes the foundation of hypothetical process that the electric field and the magnetic field are built by one charge,and then the electromagnetic field would be transferred to another charge in vacuo by the speed of light,and produces force. It points out that from the simultaneity of relativity,the force applied to charge would occur in different time in the different reference frames,the force would be neither in the same size nor in the opposite direction,and Newton’s Third Law is not valid longer, the deeper cause of these conclusions would be known. On this basis,this paper gives the basis that force would keep invariant in different reference frames,and according to this condition,with the situation of the charge that under the Coulombian force and electromagnetism,the relative form of expression and demonstration methods of electric quantity in different reference frames are given. On the basis of the hypothesis that force would keep invariant in different reference frames,with the similar derivation process,the mass relativity equation of Einstein would be obtained.

  20. Quantity of dates trumps quality of dates for dense Bayesian radiocarbon sediment chronologies - Gas ion source 14C dating instructed by simultaneous Bayesian accumulation rate modeling

    Science.gov (United States)

    Rosenheim, B. E.; Firesinger, D.; Roberts, M. L.; Burton, J. R.; Khan, N.; Moyer, R. P.

    2016-12-01

    Radiocarbon (14C) sediment core chronologies benefit from a high density of dates, even when precision of individual dates is sacrificed. This is demonstrated by a combined approach of rapid 14C analysis of CO2 gas generated from carbonates and organic material coupled with Bayesian statistical modeling. Analysis of 14C is facilitated by the gas ion source on the Continuous Flow Accelerator Mass Spectrometry (CFAMS) system at the Woods Hole Oceanographic Institution's National Ocean Sciences Accelerator Mass Spectrometry facility. This instrument is capable of producing a 14C determination of +/- 100 14C y precision every 4-5 minutes, with limited sample handling (dissolution of carbonates and/or combustion of organic carbon in evacuated containers). Rapid analysis allows over-preparation of samples to include replicates at each depth and/or comparison of different sample types at particular depths in a sediment or peat core. Analysis priority is given to depths that have the least chronologic precision as determined by Bayesian modeling of the chronology of calibrated ages. Use of such a statistical approach to determine the order in which samples are run ensures that the chronology constantly improves so long as material is available for the analysis of chronologic weak points. Ultimately, accuracy of the chronology is determined by the material that is actually being dated, and our combined approach allows testing of different constituents of the organic carbon pool and the carbonate minerals within a core. We will present preliminary results from a deep-sea sediment core abundant in deep-sea foraminifera as well as coastal wetland peat cores to demonstrate statistical improvements in sediment- and peat-core chronologies obtained by increasing the quantity and decreasing the quality of individual dates.

  1. Characterization of radiation beam filtration in computerized tomography equipments. Dosimetric influence

    International Nuclear Information System (INIS)

    Lopez Tortosa, M.; Echevarne, M.; Calzado Cantera, A.

    2000-01-01

    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

  2. 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.)

  3. Dosimetric characteristics of a TLD dosemeter with extremities

    International Nuclear Information System (INIS)

    Molina P, D.; Diaz B, E.; Lien V, R.

    1999-01-01

    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 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)

  4. Quantity Constrained General Equilibrium

    NARCIS (Netherlands)

    Babenko, R.; Talman, A.J.J.

    2006-01-01

    In a standard general equilibrium model it is assumed that there are no price restrictions and that prices adjust infinitely fast to their equilibrium values.In case of price restrictions a general equilibrium may not exist and rationing on net demands or supplies is needed to clear the markets.In

  5. Radioecological and dosimetric consequences of the Chernobyl accident in France

    International Nuclear Information System (INIS)

    Renaud, Ph.; Beaugelin, K.; Maubert, H.; Ledenvic, Ph.

    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 -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 present the 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 μSv, 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 before

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

    International Nuclear Information System (INIS)

    Wu, T.; Tan, L.; Shao, Q.; Li, Y.; Yang, L.; Zhao, C.; Xie, Y.; Zhang, S.

    2013-01-01

    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. . (authors)

  7. NOTE: The Virtual Family—development of surface-based anatomical models of two adults and two children for dosimetric simulations

    Science.gov (United States)

    Christ, Andreas; Kainz, Wolfgang; Hahn, Eckhart G.; Honegger, Katharina; Zefferer, Marcel; Neufeld, Esra; Rascher, Wolfgang; Janka, Rolf; Bautz, Werner; Chen, Ji; Kiefer, Berthold; Schmitt, Peter; Hollenbach, Hans-Peter; Shen, Jianxiang; Oberle, Michael; Szczerba, Dominik; Kam, Anthony; Guag, Joshua W.; Kuster, Niels

    2010-01-01

    The objective of this study was to develop anatomically correct whole body human models of an adult male (34 years old), an adult female (26 years old) and two children (an 11-year-old girl and a six-year-old boy) for the optimized evaluation of electromagnetic exposure. These four models are referred to as the Virtual Family. They are based on high resolution magnetic resonance (MR) images of healthy volunteers. More than 80 different tissue types were distinguished during the segmentation. To improve the accuracy and the effectiveness of the segmentation, a novel semi-automated tool was used to analyze and segment the data. All tissues and organs were reconstructed as three-dimensional (3D) unstructured triangulated surface objects, yielding high precision images of individual features of the body. This greatly enhances the meshing flexibility and the accuracy with respect to thin tissue layers and small organs in comparison with the traditional voxel-based representation of anatomical models. Conformal computational techniques were also applied. The techniques and tools developed in this study can be used to more effectively develop future models and further improve the accuracy of the models for various applications. For research purposes, the four models are provided for free to the scientific community.

  8. A Monte Carlo dosimetric quality assurance system for dynamic intensity-modulated radiotherapy

    International Nuclear Information System (INIS)

    Takegawa, Hideki; Yamamoto, Tokihiro; Miyabe, Yuki; Teshima, Teruki; Kunugi, Tomoaki; Yano, Shinsuke; Mizowaki, Takashi; Nagata, Yasushi; Hiraoka, Masahiro

    2005-01-01

    We are developing a Monte Carlo (MC) dose calculation system, which can resolve dosimetric issues derived from multileaf collimator (MLC) design for routine dosimetric quality assurance (QA) of intensity-modulated radiotherapy (IMRT). The treatment head of the medical linear accelerator equipped with MLC was modeled using the EGS4 MC code. A graphical user interface (GUI) application was developed to implement MC dose computation in the CT-based patient model and compare the MC calculated results with those of a commercial radiotherapy treatment planning (RTP) system, Varian Eclipse. To reduce computation time, the EGS4 MC code has been parallelized on massive parallel processing (MPP) system using the message passing interface (MPI). The MC treatment head model and MLC model were validated by the measurement data sets of percentage depth dose (PDD) and off-center ratio (OCR) in the water phantom and the film measurements for the static and dynamic test patterns, respectively. In the treatment head model, the MC calculated results agreed with those of measurements for both of PDD and OCR. The MC could reproduce all of the MLC dosimetric effects. A quantitative comparison between the results of MC and Eclipse was successfully performed with the GUI application. Parallel speed-up became almost linear. An MC dosimetric QA system for dynamic IMRT has been developed, however there were large dose discrepancies between the MC and the measurement in the MLC model simulation, which are now being investigated. (author)

  9. Internal dosimetric evaluation due to uranium aerosols

    International Nuclear Information System (INIS)

    Garcia Aguilar Juan; Delgado Avila Gustavo

    1991-01-01

    The present work has like object to carry out the internal dosimetric evaluation to the occupationally exposed personnel, due to the inhalation of aerosols of natural uranium and enriched in the pilot plant of nuclear fuel production of the National Institute of Nuclear Research

  10. ESR dosimetric properties of some biomineral materials

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Gamal M. [Department of Ionizing Radiation Metrology, National Institute for Standards (NIS), Tersa Street, El-Haram, El-Giza, P.O. Box 136 Giza, El-Giza (Egypt)]. E-mail: gamalhassan65@hotmail.com; Sharaf, M.A. [Department of Ionizing Radiation Metrology, National Institute for Standards (NIS), Tersa Street, El-Haram, El-Giza, P.O. Box 136 Giza, El-Giza (Egypt)

    2005-02-01

    Dosimetric properties of g-irradiated modern coral and bioactive glass (Bio-G) samples analyzed with electron spin resonance (ESR) have been separately reported (Hassan et al., 2004; Sharaf and Hassan, 2004) and compared with alanine. These are combined here to allow a three-way comparison between these materials.

  11. Threshold quantities for helminth infections

    NARCIS (Netherlands)

    Heesterbeek, J.A.P.; Roberts, M.G.

    1995-01-01

    For parasites with a clearly defined life-cycle we give threshold quantities that determine the stability of the parasite-free steady state for autonomous and periodic deterministic systems formulated in terms of mean parasite burdens. We discuss the biological interpretations of the quantities, how

  12. Quantity Stickiness versus Stackelberg Leadership

    Science.gov (United States)

    Ferreira, F. A.

    2008-10-01

    We study the endogenous Stackelberg relations in a dynamic market. We analyze a twice-repeated duopoly where, in the beginning, each firm chooses either a quantity-sticky production mode or a quantity-flexible production mode. The size of the market becomes observable after the first period. In the second period, a firm can adjust its quantity if, and only if, it has adopted the flexible mode. Hence, if one firm chooses the sticky mode whilst the other chooses the flexible mode, then they respectively play the roles of a Stackelberg leader and a Stackelberg follower in the second marketing period. We compute the supply quantities at equilibrium and the corresponding expected profits of the firms. We also analyze the effect of the slope parameter of the demand curve on the expected supply quantities and on the profits.

  13. Quantity Stickiness versus Stackelberg Leadership

    International Nuclear Information System (INIS)

    Ferreira, F. A.

    2008-01-01

    We study the endogenous Stackelberg relations in a dynamic market. We analyze a twice-repeated duopoly where, in the beginning, each firm chooses either a quantity-sticky production mode or a quantity-flexible production mode. The size of the market becomes observable after the first period. In the second period, a firm can adjust its quantity if, and only if, it has adopted the flexible mode. Hence, if one firm chooses the sticky mode whilst the other chooses the flexible mode, then they respectively play the roles of a Stackelberg leader and a Stackelberg follower in the second marketing period. We compute the supply quantities at equilibrium and the corresponding expected profits of the firms. We also analyze the effect of the slope parameter of the demand curve on the expected supply quantities and on the profits.

  14. Validation of mathematical models for the prediction of organs-at-risk dosimetric metrics in high-dose-rate gynecologic interstitial brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Damato, Antonio L.; Viswanathan, Akila N.; Cormack, Robert A. [Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts 02115 (United States)

    2013-10-15

    Purpose: Given the complicated nature of an interstitial gynecologic brachytherapy treatment plan, the use of a quantitative tool to evaluate the quality of the achieved metrics compared to clinical practice would be advantageous. For this purpose, predictive mathematical models to predict the D{sub 2cc} of rectum and bladder in interstitial gynecologic brachytherapy are discussed and validated.Methods: Previous plans were used to establish the relationship between D2cc and the overlapping volume of the organ at risk with the targeted area (C0) or a 1-cm expansion of the target area (C1). Three mathematical models were evaluated: D{sub 2cc}=α*C{sub 1}+β (LIN); D{sub 2cc}=α– exp(–β*C{sub 0}) (EXP); and a mixed approach (MIX), where both C{sub 0} and C{sub 1} were inputs of the model. The parameters of the models were optimized on a training set of patient data, and the predictive error of each model (predicted D{sub 2cc}− real D{sub 2cc}) was calculated on a validation set of patient data. The data of 20 patients were used to perform a K-fold cross validation analysis, with K = 2, 4, 6, 8, 10, and 20.Results: MIX was associated with the smallest mean prediction error <6.4% for an 18-patient training set; LIN had an error <8.5%; EXP had an error <8.3%. Best case scenario analysis shows that an error ≤5% can be achieved for a ten-patient training set with MIX, an error ≤7.4% for LIN, and an error ≤6.9% for EXP. The error decreases with the increase in training set size, with the most marked decrease observed for MIX.Conclusions: The MIX model can predict the D{sub 2cc} of the organs at risk with an error lower than 5% with a training set of ten patients or greater. The model can be used in the development of quality assurance tools to identify treatment plans with suboptimal sparing of the organs at risk. It can also be used to improve preplanning and in the development of real-time intraoperative planning tools.

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

    OpenAIRE

    Wu, Edward; Kuo, Shu-Lung

    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...

  16. NTCP models for patient-rated xerostomia and sticky saliva after treatment with intensity modulated radiotherapy for head and neck cancer: The role of dosimetric and clinical factors

    International Nuclear Information System (INIS)

    Beetz, Ivo; Schilstra, Cornelis; Schaaf, Arjen van der; Heuvel, Edwin R. van den; Doornaert, Patricia; Luijk, Peter van; Vissink, Arjan; Laan, Bernard F.A.M. van der; Leemans, Charles R.; Bijl, Henk P.; Christianen, Miranda E.M.C.; Steenbakkers, Roel J.H.M.; Langendijk, Johannes A.

    2012-01-01

    Purpose: The purpose of this multicentre prospective study was to develop multivariable logistic regression models to make valid predictions about the risk of moderate-to-severe patient-rated xerostomia (XER M6 ) and sticky saliva 6 months (STIC M6 ) after primary treatment with intensity modulated radiotherapy (IMRT) with or without chemotherapy for head and neck cancer (HNC). Methods and materials: The study population was composed of 178 consecutive HNC patients treated with IMRT. All patients were included in a standard follow up programme in which acute and late side effects and quality of life were prospectively assessed, prior to, during and after treatment. The primary endpoints were XER M6 and STIC M6 as assessed by the EORTC QLQ-H and N35 after completing IMRT. Organs at risk (OARs) potentially involved in salivary function were delineated on planning-CT, including the parotid, submandibular and sublingual glands and the minor glands in the soft palate, cheeks and lips. Patients with moderate-to-severe xerostomia or sticky saliva, respectively, at baseline were excluded. The optimal number of variables for a multivariate logistic regression model was determined using a bootstrapping method. Results: Eventually, 51.6% of the cases suffered from XER M6 . The multivariate analysis showed that the mean contralateral parotid gland dose and baseline xerostomia (none vs. a bit) were the most important predictors for XER M6 . For the multivariate NTCP model, the area under the receiver operating curve (AUC) was 0.68 (95% CI 0.60–0.76) and the discrimination slope was 0.10, respectively. Calibration was good with a calibration slope of 1.0. At 6 months after IMRT, 35.6% of the cases reported STIC M6 . The mean contralateral submandibular gland dose, the mean sublingual dose and the mean dose to the minor salivary glands located in the soft palate were most predictive for STIC M6 . For this model, the AUC was 0.70 (95% CI 0.61–0.78) and the discrimination slope

  17. Evaluation of material heterogeneity dosimetric effects using radiochromic film for COMS eye plaques loaded with 125I seeds (model I25.S16)

    International Nuclear Information System (INIS)

    Acar, Hilal; Chiu-Tsao, Sou-Tung; Özbay, İsmail; Kemikler, Gönül; Tuncer, Samuray

    2013-01-01

    Purpose: (1) To measure absolute dose distributions in eye phantom for COMS eye plaques with 125 I seeds (model I25.S16) using radiochromic EBT film dosimetry. (2) To determine the dose correction function for calculations involving the TG-43 formalism to account for the presence of the COMS eye plaque using Monte Carlo (MC) method specific to this seed model. (3) To test the heterogeneous dose calculation accuracy of the new version of Plaque Simulator (v5.3.9) against the EBT film data for this seed model. Methods: Using EBT film, absolute doses were measured for 125 I seeds (model I25.S16) in COMS eye plaques (1) along the plaque's central axis for (a) uniformly loaded plaques (14–20 mm in diameter) and (b) a 20 mm plaque with single seed, and (2) in off-axis direction at depths of 5 and 12 mm for all four plaque sizes. The EBT film calibration was performed at 125 I photon energy. MC calculations using MCNP5 code for a single seed at the center of a 20 mm plaque in homogeneous water and polystyrene medium were performed. The heterogeneity dose correction function was determined from the MC calculations. These function values at various depths were entered into PS software (v5.3.9) to calculate the heterogeneous dose distributions for the uniformly loaded plaques (of all four sizes). The dose distributions with homogeneous water assumptions were also calculated using PS for comparison. The EBT film measured absolute dose rate values (film) were compared with those calculated using PS with homogeneous assumption (PS Homo) and heterogeneity correction (PS Hetero). The values of dose ratio (film/PS Homo) and (film/PS Hetero) were obtained. Results: The central axis depth dose rate values for a single seed in 20 mm plaque measured using EBT film and calculated with MCNP5 code (both in ploystyrene phantom) were compared, and agreement within 9% was found. The dose ratio (film/PS Homo) values were substantially lower than unity (mostly between 0.8 and 0.9) for all

  18. Monte Carlo dosimetric characterization of the Flexisource Co-60 high-dose-rate brachytherapy source using PENELOPE.

    Science.gov (United States)

    Almansa, Julio F; Guerrero, Rafael; Torres, Javier; Lallena, Antonio M

    60 Co sources have been commercialized as an alternative to 192 Ir sources for high-dose-rate (HDR) brachytherapy. One of them is the Flexisource Co-60 HDR source manufactured by Elekta. The only available dosimetric characterization of this source is that of Vijande et al. [J Contemp Brachytherapy 2012; 4:34-44], whose results were not included in the AAPM/ESTRO consensus document. In that work, the dosimetric quantities were calculated as averages of the results obtained with the Geant4 and PENELOPE Monte Carlo (MC) codes, though for other sources, significant differences have been quoted between the values obtained with these two codes. The aim of this work is to perform the dosimetric characterization of the Flexisource Co-60 HDR source using PENELOPE. The MC simulation code PENELOPE (v. 2014) has been used. Following the recommendations of the AAPM/ESTRO report, the radial dose function, the anisotropy function, the air-kerma strength, the dose rate constant, and the absorbed dose rate in water have been calculated. The results we have obtained exceed those of Vijande et al. In particular, the absorbed dose rate constant is ∼0.85% larger. A similar difference is also found in the other dosimetric quantities. The effect of the electrons emitted in the decay of 60 Co, usually neglected in this kind of simulations, is significant up to the distances of 0.25 cm from the source. The systematic and significant differences we have found between PENELOPE results and the average values found by Vijande et al. point out that the dosimetric characterizations carried out with the various MC codes should be provided independently. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  19. 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.

  20. Irradiator, particularly for calibration of dosimetric devices

    International Nuclear Information System (INIS)

    Brethon, J.-P.; Germond, Philippe; Papot, Lucien.

    1977-01-01

    An irradiator is presented for dosimetric calibration, of the kind comprising one or more radiation emmitting sources, each one placed behind a collimator of which the orifice is covered by a shutter outside the periods of irradiation. This shutter is composed of two preset drop shutters located one behind the other, the drop of the outside curtain of the first shutter causes the beam to pass through and the drop of the internal curtain of the second shutter cuts the beam [fr

  1. Modeling the effect of abandonment process of cultivated land on water quantity and quality using SWAT in a hilly watersheds of western Japan

    Science.gov (United States)

    Shimizu, Y.; Onodera, S. I.; Matsumori, K.

    2016-12-01

    Some of previous studies argued that the total area of cultivated land has already passed through its peak at the global scale, and increase of abandoned cultivated land will be projected. The problems result from the abandonment on water quantity and quality could be revealed next 20 to 30 years. Although Japan has same with this trend, the situation could be more serious owing to its topographical characteristic. Therefore, it is important to evaluate the effect of the abandonment process of cultivated land on water quantity and quality at the watershed scale. Several scales of watersheds (2.6 km2 - 2,670 km2) located in the Chugoku Region in western Japan were the target in this study. To examine the effect of abandoned cultivated land on water quality, we used Soil and Water Assessment Tool version 2012 Rev632. The parameters related water cycle, sediment, and nutrient yields were calibrated using the river discharge and water quality that are observed at outlets of the watersheds using SWATCUP version 5.1.6 with SUFI2 method. The result of the analysis that cultivated land in the watershed will be abandoned, increasing of maximum river discharge and fluxes of organic nitrogen and particulate phosphorus were found under heavy rainfall events. Some difference on the magnitude of fluxes was found between crop types and tillage conditions of the abandoned land. Although the surface is undergoing afforestation process that could stabilize the river discharge by vegetation cover after the abandonment, it takes more than 10 years to become rewilding condition. The results indicate that the beginning of several years which begin to be abandoned is the most critical period of discharge water quantity and quality. Furthermore, climate change effect such as increasing rainfall intensity could enhance this trend so that it is possible to be a trigger to cause a disaster such as a landslide or flood if cultivated land locates in hilly and mountainous area will be abandoned

  2. 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.

  3. Active pixel as dosimetric device for interventional radiology

    International Nuclear Information System (INIS)

    Servoli, L.; Baldaccini, F.; Biasini, M.; Checcucci, B.; Chiocchini, S.; Cicioni, R.; Conti, E.; Di Lorenzo, R.; Dipilato, A.C.; Esposito, A.; Fanó, L.; Paolucci, M.; Passeri, D.; Pentiricci, A.

    2013-01-01

    Interventional Radiology (IR) is a subspecialty of radiology comprehensive of all minimally invasive diagnostic and therapeutic procedures performed using radiological devices to obtain image guidance. The interventional procedures are potentially harmful for interventional radiologists and medical staff due to the X-ray diffusion by the patient's body. The characteristic energy range of the diffused photons spans few tens of keV. In this work we will present a proposal for a new X-ray sensing element in the energy range of interest for IR procedures. The sensing element will then be assembled in a dosimeter prototype, capable of real-time measurement, packaged in a small form-factor, with wireless communication and no external power supply to be used for individual operators dosimetry for IR procedures. For the sensor, which is the heart of the system, we considered three different Active Pixel Sensors (APS). They have shown a good capability as single X-ray photon detectors, up to several tens keV photon energy. Two dosimetric quantities have been considered, the number of detected photons and the measured energy deposition. Both observables have a linear dependence with the dose, as measured by commercial dosimeters. The uncertainties in the measurement are dominated by statistic and can be pushed at ∼5% for all the sensors under test

  4. A Dosimetric Evaluation of The Eclipse and Pinnacle Treatment Planning Systems in Treatment of Vertebral Bodies Using IMRT and VMAT with Modeled and Commissioned Flattening Filter Free (FFF) Fields

    Science.gov (United States)

    Ajo, Ramzi, Jr.

    Modern treatment planning systems (TPS's) utilize different algorithms in computing dose within the patient medium. The algorithms rely on properly modeled clinical setups in order to perform optimally. Aside from various parameters of the beam, modifiers, such as multileaf collimators (MLC's), must also be modeled properly. That could not be more true today, where dynamic delivery such as intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) are being increasingly utilized due to their ability to deliver higher dose precisely to the target while sparing more surrounding normal tissue. Two of the most popular TPS's, Pinnacle (Philips) and Eclipse (Varian), were compared, with special emphasis placed on parameterization of the dosimetric leaf gap (DLG) in Eclipse. The DLG is a parameter that accounts for Varian's rounded MLC leaf ends. While Pinnacle accounts for the rounded leaf end by modeling the MLC's, Eclipse uses a measured parameter. This study investigated whether a single value measured DLG is sufficient for dynamic delivery. Using five planning volumes for vertebral body SBRT treatments, each prescribed for 3000 cGy in 5 fractions, an array of 20 treatment plans was generated using varying energies of 6MV-FFF and 10MV-FFF. Treatment techniques consisted of 9-field Step-and-shoot IMRT, and dual-arc VMAT using patient specific optimization criteria in the Pinnacle TPS v9.8. Each plan was normalized to ensure coverage of 3000cGy to 95% of the target volume. The dose was computed in Pinnacle v9.8, with the Collapsed Cone Convolution Superposition algorithm and Eclipse v11, with the Acuros XB algorithm, using a dose grid resolution of 2 mm in both systems. Dose volume histograms (DVH's) were generated for a comparison of max and mean dose to the targets and spinal cord, as well as 95% coverage of the targets and the volume of the spinal cord receiving 14.5 Gy (V14.5). Patient specific quality assurance (PSQA) fields were

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

    Science.gov (United States)

    Wang, Jiazhou; Jin, Xiance; Zhao, Kuaike; Peng, Jiayuan; Xie, Jiang; Chen, Junchao; Zhang, Zhen; Studenski, Matthew; Hu, Weigang

    2015-02-01

    To investigate the feasibility of the dosimetric Pareto front (PF) prediction based on patient's anatomic and dosimetric parameters for esophageal cancer patients. 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. 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. 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.

  6. 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

  7. 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…

  8. Definitions of Quantities and Units.

    Science.gov (United States)

    Spurgin, C. B.

    1983-01-01

    Compares various methods of defining derived quantities, arguing for a definitional formula using base or fundamental units in a word equation, or symbol-equations with the symbols explained. Suggests that fundamental units be defined operationally or left regarded as intuitive as in the case of length and time. (JM)

  9. Gamma dosimetric parameters in some skeletal muscle relaxants

    Indian Academy of Sciences (India)

    ... 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 ...

  10. Dosimetric of extremities with Dosemeters thermoluminescent in Cuba

    International Nuclear Information System (INIS)

    Molina Perez, D.; Diaz Bernal, E.; Vera Alonso, L.

    1998-01-01

    From final of the year 1995 in the CPHR implement the service of monitoring of the extremities using Dosemeter thermoluminescent (TL). The dosemeter consists on a metallic ring with a circular hole where a detector of LiF:Mg,Ti is placed (model JR1152C) of 5x5x0.9 mm 3 , covered by a fine layer of polyethylene. In the work the characteristic dosimetric as of the dosemeter is studied it satisfies the main requirements for their use in the monitoring from the exhibition to radiation photonic of the extremities. The doses are also presented registered during the first two years of operation of the service. The results obtained until the moment point out to you practice them of nuclear medicine, radiotherapy and production of substances radioactive how as of more contribution

  11. Dosimetric adaptive IMRT driven by fiducial points

    International Nuclear Information System (INIS)

    Crijns, Wouter; Van Herck, Hans; Defraene, Gilles; Van den Bergh, Laura; Haustermans, Karin; Slagmolen, Pieter; Maes, Frederik; Van den Heuvel, Frank

    2014-01-01

    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

  12. ESR dosimetric properties of modern coral reef

    Energy Technology Data Exchange (ETDEWEB)

    Sharaf, M.A. E-mail: mokhtar_sharaf@yahoo.com; Hassan, Gamal M

    2004-06-01

    Modern coral reef samples from Egypt were irradiated with {sup 60}Co{gamma}-rays to study radicals for dosimetric materials with electron spin resonance (ESR). The ESR spectrum for the radical species in unirradiated coral is characterized by four signals with spectroscopic splitting factors of g=2.0056, 2.0030, 2.0006 and 1.997. The signal at g=2.0006{+-}0.0005 is ascribed to free rotation CO{sub 2}{sup -} radicals and used as a dosimetric one. The response to {gamma}-ray doses ranging from 5 to 10{sup 3} Gy and the thermal stability has been studied. The number of free radicals per 100 eV (G-value) was found to be 0.45 {+-} 0.1 and 0.9 {+-} 0.18 for coral and alanine, respectively. The lifetime of radicals and the activation energy were estimated from Arrhenius plots to be approximately 8 x 10{sup 5} {+-} 1.6 x 10{sup 5} years, and 1.12 eV, respectively.

  13. Dosimetric evaluation in radiation synovectomy

    Directory of Open Access Journals (Sweden)

    Carla Flávia de Lima

    2005-10-01

    Full Text Available Rheumatoid arthritis can manifest itself through synovitis, of which the knee is the common locale. The treatment using an intra-articular radioisotope injection has been applied in various countries. In this work, the dose of radioactive material absorbed in the joint is evaluated, taking into consideration the dose received in the articular cartilage and adjacencies using a three-dimensional voxel model representing the knee. The radioisotopes studied were Samarium-153 and Dysprosium-165. The results show that the synovial membrane receives 85 to 98% of the normalized dose taken from all voxels representative of the synovium. The following features of 153Sm and of 165Dy - its short physical half-life, the gamma emissions with low energy which allow monitoring the injection trough scintigraphy images, the possibility of binding themselves to macroaggregates that are retained in the joint, the high percentage of the effective dose spread in the synovial membrane - make these suitable radioisotopes for radiation synovectomy.A artrite reumatóide pode se manifestar usualmente pela inflamação da membrana sinovial caracterizada como sinovite, sendo o joelho um substrato comum. O tratamento com a injeção intra-articular de radioisótopo, ou sinovectomia radioisotópica, vem sendo estudado. Neste trabalho será calculada a dose absorvida na sinóvia e nas adjacências através de um modelo tridimensional de voxels. Os radioisótopos estudados foram o Samário-153 e o Disprósio-165. Os resultados obtidos mostraram que uma taxa de dose máxima normalizada variando de 85 a 98% da dose máxima foi atingida em todos os voxels representativos da membrana sinovial. As características nucleares do Samário-153 e do Disprósio-165, associadas à taxa de dose efetiva recebida na articulação, fazem destes radioisótopos uma escolha na sinovectomia radioisotópica.

  14. 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

    . 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....

  15. How necessary are the new quantities

    International Nuclear Information System (INIS)

    Kraus, W.

    1991-01-01

    The necessity of the ICRU operational quantities is discussed from the point of view of practical, opertional radiation protection, on the basis of ICRU report 43. It is clear that, although the new quantities have some advantages over previous systems of operational quantities, there are some disadvantages as well. The decision to adopt these quantities is, therefore, not clear cut. (orig.)

  16. 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.

  17. Dimension and deriving manner for derived quantities

    International Nuclear Information System (INIS)

    Zhao Zhixiang

    1993-01-01

    Most physical quantities we are interested in are derived from some directly measured physical quantities. To obtain correct least-square result in derived quantity space, one must pay attention to inconsistencies problem to avoid ppp phenomenon in generating derived quantities and their covariance matrix. The situation is complicated by the problems of dimension and deriving manner for derived quantities. Some more general problems, which are independent of ppp, are discussed

  18. Establishment of a dosimetric system for high doses using glasses

    International Nuclear Information System (INIS)

    Correa Quezada, Valeria de la Asuncion

    1997-01-01

    A routine dosimetric system was developed using commercial glass samples. The dosimetric characteristics of national and imported samples were studied: batch uniformity, response repeatability, reutilization, absorbed dose response, detection range, response stability as a function of absorbed dose, storage temperature and thermal treatments pre- and post-irradiation, using the optical absorption technique. As an application, the dosimetric system was tested in a flower irradiation process at IPEN. All the obtained results show the usefulness of the proposed system for high dose dosimetry. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Delaney, Alexander R., E-mail: a.delaney@vumc.nl; Tol, Jim P.; Dahele, Max; Cuijpers, Johan; Slotman, Ben J.; Verbakel, Wilko F.A.R.

    2016-03-01

    Purpose: 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. Methods and Materials: Clinical plans from 70 head and neck cancer patients comprised the uncleaned (UC) Model{sub UC}, from which outliers were cleaned (C) to create Model{sub C}. The last 5 to 40 patients of Model{sub C} were replanned with no attempt to spare the salivary glands. These substantial dosimetric outliers were reintroduced to the model in increments of 5, creating Model{sub 5} to Model{sub 40} (Model{sub 5-40}). These models were used to create plans for a 10-patient evaluation group. Plans from Model{sub UC} and Model{sub C}, and Model{sub C} and Model{sub 5-40} were compared on the basis of boost (B) and elective (E) target volume homogeneity indexes (HI{sub B}/HI{sub E}) and mean doses to oral cavity, composite salivary glands (comp{sub sal}) and swallowing (comp{sub swal}) structures. Results: On average, outlier removal (Model{sub C} vs Model{sub UC}) had minimal effects on HI{sub B}/HI{sub E} (0%-0.4%) and sparing of organs at risk (mean dose difference to oral cavity and comp{sub sal}/comp{sub swal} were ≤0.4 Gy). Model{sub 5-10} marginally improved comp{sub sal} sparing, whereas adding a larger number of outliers (Model{sub 20-40}) led to deteriorations in comp{sub sal} 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. Conclusions: Overall

  20. 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

  1. Thermoluminescent dosimetric properties of Descalvado sand

    International Nuclear Information System (INIS)

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

    2006-01-01

    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 ( 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)

  2. 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)

  3. 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...

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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. (paper)

  5. Balancing Teacher Quality and Quantity

    Science.gov (United States)

    Bond, Helen

    The world is facing a shortage of trained teachers. According to the 2010 Global Monitoring Report approximately 10.3 million teachers will be needed globally to staff classrooms from Bangkok to Canada. The situation is worse in Sub-Saharan Africa. Estimates suggest that approximately 1.2 million new teachers will be needed in Sub-Saharan Africa alone to achieve universal primary education goals by 2015. Increases in primary school enrollments, drought, and HIV-AIDS have exacerbated the need for well trained teachers. Despite the need, the focus is on balancing quality with quantity. An effective teacher is deemed a critical element, although not the only one, in a student's success in the classroom. This paper focuses on the dilemma of meeting universal primary education goals in Sub-Saharan Africa, while maintaining teacher quality in fragile contexts.

  6. Architecture from quantity to quality

    Directory of Open Access Journals (Sweden)

    Luca Gibello

    2015-11-01

    Full Text Available Having surpassed the problem of quantity, it is necessary to now address the problem of widespread quality where we have ensured, that all land surface areas be defined by an architecture project, or rather in a holistic, integrated and multidisciplinary approach. The objective then, is know how to intervene in the scope of transformation, revitalization, reconversion and reuse in urban design. Architecture must know the ‘catalogs’ that provide best practice for design processes and products, yet know to avoid the populist tendencies of certain participatory design processes and know how to take into account the requests of users. Doing so, architecture can exercise the ability to reason critically, which is the most valuable skill designer should have.

  7. Dosimetric validation of Monaco treatment planning system on an Elekta VersaHD linear accelerator.

    Science.gov (United States)

    Narayanasamy, Ganesh; Saenz, Daniel L; Defoor, Dewayne; Papanikolaou, Niko; Stathakis, Sotirios

    2017-11-01

    The purpose of this study is to perform dosimetric validation of Monaco treatment planning system version 5.1. The Elekta VersaHD linear accelerator with high dose rate flattening filter-free photon modes and electron energies was used in this study. The dosimetric output of the new Agility head combined with the FFF photon modes warranted this investigation into the dosimetric accuracy prior to clinical usage. A model of the VersaHD linac was created in Monaco TPS by Elekta using commissioned beam data including percent depth dose curves, beam profiles, and output factors. A variety of 3D conformal fields were created in Monaco TPS on a combined Plastic water/Styrofoam phantom and validated against measurements with a calibrated ion chamber. Some of the parameters varied including source to surface distance, field size, wedges, gantry angle, and depth for all photon and electron energies. In addition, a series of step and shoot IMRT, VMAT test plans, and patient plans on various anatomical sites were verified against measurements on a Delta 4 diode array. The agreement in point dose measurements was within 2% for all photon and electron energies in the homogeneous phantom and within 3% for photon energies in the heterogeneous phantom. The mean ± SD gamma passing rates of IMRT test fields yielded 93.8 ± 4.7% based on 2% dose difference and 2 mm distance-to-agreement criteria. Eight previously treated IMRT patient plans were replanned in Monaco TPS and five measurements on each yielded an average gamma passing rate of 95% with 6.7% confidence limit based on 3%, 3 mm gamma criteria. This investigation on dosimetric validation ensures accuracy of modeling VersaHD linac in Monaco TPS thereby improving patient safety. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  8. Determination of Absorbed Dose Using a Dosimetric Film

    International Nuclear Information System (INIS)

    Scarlat, F.; Scarisoreanu, A.; Oane, M.; Badita, E.; Mitru, E.

    2009-01-01

    This paper presents the absorbed dose measurements by means of the irradiated dosimetric reference films. The dose distributions were made by MULTIDATA film densitometer using RTD-4 software, in INFLPR Linear Accelerator Department

  9. Are necessary unmeasurable quantities in radiation protection?

    International Nuclear Information System (INIS)

    David, M.G.; Correa, M.F.; Videira, A.A.P.

    2016-01-01

    We discuss in this paper the metrological status of unmeasurable protection quantities and the need to maintain these kind of quantities in the system. The discussion is based on reports from the institutions responsible for the quantities and on scientific publications. In conclusion, we can say that there are alternatives for changing the system in a way that it keep just measurable quantities, nevertheless the present system is well assimilated. Even though a proposal yet to be presented for changing the system, although might simplify and improve it, is not intended to overcome the existence of unmeasurable quantities or the two kinds of quantities. (author)

  10. SHORT COMMUNICATION: On (kinds of) quantities

    Science.gov (United States)

    Mari, Luca

    2009-06-01

    The third edition of the International Vocabulary of Metrology (VIM) has introduced the concept of kind of quantity as the 'aspect common to mutually comparable quantities'. While the concept is a fundamental one, as it is relevantly used in several definitions throughout VIM, its definition is critical for several reasons. Not only is the division of the concept of 'quantity' according to 'kind of quantity' to some extent arbitrary, as noted in the Vocabulary, but also the distinction between the concepts of 'quantity' and 'kind of quantity' is to some extent arbitrary. This article discusses this subject and suggests a possible solution to some of the issues identified.

  11. 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

    .../pound quantities and inch/pound quantities to SI metric quantities. 500.19 Section 500.19 Commercial... LABELING ACT § 500.19 Conversion of SI metric quantities to inch/pound quantities and inch/pound quantities to SI metric quantities. (a) For calculating the conversion of SI metric quantities to inch/pound...

  12. Dosimetric characteristics of biological effect of sulfur-35

    International Nuclear Information System (INIS)

    Borisova, V.V.

    1990-01-01

    Experimental materials related to evaluation of dosimetric characteristics of sulfur-35 are presented. Hemogenic organs are subjected to greatest influence especially in the first hours after radionuclide entry into the organism. Comparison is made of absorbed doses in blood with observed blastomogen effect of hemogenic organs. It is noted, that quantitative evaluation of relative biological efficiency of low energy beta-emitters should be performed with account of dosimetric peculiarities of the nuclides mentioned above. 10 refs.; 3 tabs

  13. 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.

  14. Practical guide. Realisation of dosimetric studies for workplaces exhibiting a ionizing radiation exposure risk (version 4)

    International Nuclear Information System (INIS)

    2015-01-01

    This guide proposes a methodological approach to help carry out dosimetric workplace studies complying with the French regulation, and necessary to identify risks of radiological exposure, optimize radiation protection and classify the workers into different categories. Additional information is provided relating the main objectives of a workplace study, the French regulatory context, main sources and pathways of exposure to ionizing radiation. Radiation protection and operational quantities are reminded. Recommendations about the selection and use of detectors and about the implementation of calculation methods are also provided. The general methodological approach is applied and developed into 'workplace sheets', each one devoted to a particular type of workplace. Up to now only sheets related to medical field have been developed. By extension, advices for classify the workplaces into different areas are also supplied. (authors)

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

    Science.gov (United States)

    Tournier, B.; Itié, C.; Médioni, R.; 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. Investigating the dosimetric impact of seed location uncertainties in Collaborative Ocular Melanoma Study-based eye plaques.

    Science.gov (United States)

    Johnson, Jedediah E; Deufel, Christopher L; Furutani, Keith M

    2016-01-01

    To quantify the dosimetric effects of random and systematic seed position uncertainties in Collaborative Ocular Melanoma Study-based eye plaques. An eye plaque dose calculation routine was created using Task Group 43 formalism. A variety of clinical configurations were simulated, including two seed models: (125)I and (103)Pd, three eye plaque sizes, and eight plaque/eye orientations. Dose was calculated at four ocular anatomic sites and three central axis plaque depths. Random seed positional uncertainty was modeled by adding Gaussian random displacements, in one of three seed-motion degrees of freedom, to each seed's nominal coordinate. Distributions of dosimetric outcomes were obtained and fitted after 10(6) randomizations. Similar analysis was performed for deterministic, systematic shifts of the plaque along the eye surface and radially from the globe center. Random seed placement uncertainties of 0.2-mm root mean square (RMS) (amplitude) produce dose changes that are typically Eye plaque dosimetry is most sensitive to seed movement toward the center of the eye. Dosimetric uncertainty also increases with increasing dose gradients, which are typically greatest near the inner sclera, with smaller plaques, and with lower energy radionuclides (e.g., (103)Pd). Dosimetric uncertainties due to the random seed positional displacements anticipated in the clinic are expected to be <4% for each degree of freedom in most circumstances. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  17. Workplace stress experienced by quantity surveyors

    African Journals Online (AJOL)

    Workplace stress experienced by quantity surveyors. Peer reviewed and revised. Abstract. This article reports on the relationship between workplace stress of quantity surveyors and job demand, control and support factors. Using an online quantitative survey, the perceptions of workplace stress of professional quantity.

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

    International Nuclear Information System (INIS)

    Olch, A

    2014-01-01

    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, 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

  19. 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

  20. Non-Gaussianity effects in petrophysical quantities

    Science.gov (United States)

    Koohi Lai, Z.; Jafari, G. R.

    2013-10-01

    It has been proved that there are many indicators (petrophysical quantities) for the estimation of petroleum reservoirs. The value of information contained in each indicator is yet to be addressed. In this work, the most famous and applicable petrophysical quantities for a reservoir, which are the gamma emission (GR), sonic transient time (DT), neutron porosity (NPHI), bulk density (RHOB), and deep induced resistivity (ILD), have been analyzed in order to characterize a reservoir. The implemented technique is the well-logging method. Based on the log-normal model defined in random multiplicative processes, the probability distribution function (PDF) for the data sets is described. The shape of the PDF depends on the parameter λ2 which determines the efficiency of non-Gaussianity. When non-Gaussianity appears, it is a sign of uncertainty and phase transition in the critical regime. The large value and scale-invariant behavior of the non-Gaussian parameter λ2 is an indication of a new phase which proves adequate for the existence of petroleum reservoirs. Our results show that one of the indicators (GR) is more non-Gaussian than the other indicators, scale wise. This means that GR is a continuously critical indicator. But by moving windows with various scales, the estimated λ2 shows that the most appropriate indicator for distinguishing the critical regime is ILD, which shows an increase at the end of the measured region of the well.

  1. 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

  2. Dosimetric assessment of swallowing examinations with videofluoroscopy

    International Nuclear Information System (INIS)

    Costa, M.M.B.; Canevaro, L.V.; Azevedo, A.C.P.

    2001-01-01

    Dosimetric analysis measurements of the Dose-Area-Product (DAP) of 7 individuals were estimated for the deglutition dynamic using the videofluoroscopic method. The aim of this study is to establish in a preliminary way, typical DAP values for this kind of study. The DAP values were obtained attaching to the X ray tube exit, an ionization chamber from PTW and a Diamentor M4 meter. The typical DAP values obtained during the videofluoroscopic evaluation of the deglutition dynamic, including its three phases, was: 4101 ± 881 cGy.cm 2 and the typical DAP rate was 577 ± 94 cGy.cm 2 /min. These values refer to a standard patient (1.57 cm height, 56 kg. weight) and a protocol that can be performed in about 7 minutes. The values, defined herein as typical refer to the used protocol. To our knowledge, the mean DAP rate is a good parameter to estimate radiation exposure from videofluoroscopic study of swallowing process. (author)

  3. 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.

  4. 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.

  5. Dosimetric intercomparison between protons and electrons therapies applied to retinoblastoma

    International Nuclear Information System (INIS)

    Braga, Flavia Vieira

    2008-01-01

    In this work we propose a construction of a simple human eye model in order to simulate the dosimetric response for a treatment with protons and electrons in a retinoblastoma cancer. The computational tool used in this simulation was the Geant4 code, in the version 4.9.1, all these package are free and permit simulate the interaction of radiation with matter. In our simulation we use a box with 4 cm side, with water, for represent the human eye. The simulation was performed considering mono energetics beams of protons and electrons with energy range between 50 and 70 MeV for protons and 2 and 10 MeV for electrons. The simulation was based on the advanced hadron therapy example of the Geant 4 code. In these example the phantom is divided in voxels with 0.2 mm side and it is generated the energy deposited in each voxel. The simulation results show the energy deliver in each voxel, with these energie we can calculate the dose deposited in that region. We can see the dose profile of, proton and electron, and we can see in both cases that for protons the position of delivered dose is well know, that happen in the position where the proton stop, for electrons the energies is delivered along the way and pass the desired position for high dose deposition. (author)

  6. 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.

  7. 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

  8. 'Odontologic dosimetric card' experiments and simulations using Monte Carlo methods

    International Nuclear Information System (INIS)

    Menezes, C.J.M.; Lima, R. de A.; Peixoto, J.E.; Vieira, J.W.

    2008-01-01

    The techniques for data processing, combined with the development of fast and more powerful computers, makes the Monte Carlo methods one of the most widely used tools in the radiation transport simulation. For applications in diagnostic radiology, this method generally uses anthropomorphic phantoms to evaluate the absorbed dose to patients during exposure. In this paper, some Monte Carlo techniques were used to simulation of a testing device designed for intra-oral X-ray equipment performance evaluation called Odontologic Dosimetric Card (CDO of 'Cartao Dosimetrico Odontologico' in Portuguese) for different thermoluminescent detectors. This paper used two computational models of exposition RXD/EGS4 and CDO/EGS4. In the first model, the simulation results are compared with experimental data obtained in the similar conditions. The second model, it presents the same characteristics of the testing device studied (CDO). For the irradiations, the X-ray spectra were generated by the IPEM report number 78, spectrum processor. The attenuated spectrum was obtained for IEC 61267 qualities and various additional filters for a Pantak 320 X-ray industrial equipment. The results obtained for the study of the copper filters used in the determination of the kVp were compared with experimental data, validating the model proposed for the characterization of the CDO. The results shower of the CDO will be utilized in quality assurance programs in order to guarantee that the equipment fulfill the requirements of the Norm SVS No. 453/98 MS (Brazil) 'Directives of Radiation Protection in Medical and Dental Radiodiagnostic'. We conclude that the EGS4 is a suitable code Monte Carlo to simulate thermoluminescent dosimeters and experimental procedures employed in the routine of the quality control laboratory in diagnostic radiology. (author)

  9. Design and dosimetric considerations of a modified COMS plaque: The reusable 'seed-guide' insert

    International Nuclear Information System (INIS)

    Astrahan, Melvin A.; Szechter, Andrzej; Finger, Paul T.

    2005-01-01

    The Collaborative Ocular Melanoma Study (COMS) developed a standardized set of eye plaques that consist of a 0.5 mm thick bowl-like gold alloy backing with a cylindrical collimating lip. A Silastic seed carrier into which 125 I seeds are loaded was designed to fit within the backing. The carrier provides a standardized seed pattern and functions to offset the seeds by 1.0 mm from the concave (front) surface of the carrier. These Silastic carriers have been found to be difficult to load, preclude flash sterilization, and are a source of dosimetric uncertainty because the effective atomic number of Silastic is significantly higher than that of water. The main dosimetric effect of the Silastic carrier is a dose-reduction (compared to homogeneous water) of approximately 10%-15% for 125 I radiation. The dose reduction is expected to be even greater for 103 Pd radiation. In an attempt to improve upon, yet retain as much of the familiar COMS design as possible, we have developed a thin 'seed-guide' insert made of gold alloy. This new insert has cutouts which match the seed pattern of the Silastic carrier, but allows the seeds to be glued directly to the inner surface of the gold backing using either dental acrylic or a cyanoacrylate adhesive. When glued directly to the gold backing the seeds are offset a few tenths of a millimeter further away from the scleral surface compared to using the Silastic carrier. From a dosimetric perspective, the space formerly occupied by the Silastic carrier is now assumed to be water equivalent. Water equivalency is a desirable attribute for this space because it eliminates the dosimetric uncertainties related to the atomic composition of Silastic and thereby facilitates the use of either 125 I and/or 103 Pd seeds. The caveat is that a new source of dosimetric uncertainty would be introduced were an air bubble to become trapped in this space during or after the surgical insertion. The presence of air in this space is modeled and the

  10. Technical requirements for implementation of an individual monitoring service for evaluation of operational quantity HP(10) using thermoluminescent dosimetry

    International Nuclear Information System (INIS)

    Francisco, Adelaide Benedita Armando

    2016-01-01

    This work aims to establish technical requirements for the development of a TLDs system for the assessment of operational quantity H 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)

  11. FBX aqueous chemical dosimeter for measurement of dosimetric parameters.

    Science.gov (United States)

    Moussous, O; Medjadj, T; Benguerba, M

    2011-02-01

    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 (60)Co γ-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 (60)Co with reasonable accuracy. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Average Transverse Momentum Quantities Approaching the Lightfront

    NARCIS (Netherlands)

    Boer, Daniel

    In this contribution to Light Cone 2014, three average transverse momentum quantities are discussed: the Sivers shift, the dijet imbalance, and the p (T) broadening. The definitions of these quantities involve integrals over all transverse momenta that are overly sensitive to the region of large

  13. 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...

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

    African Journals Online (AJOL)

    The research established that quantity surveyors regarded handing in their CPD records on time as the most important factor when participating in CPD. It was found that quantity surveyors lack a structured approach to CPD, suggesting that they merely engage in CPD when they have adequate time. With regard to CPD ...

  15. Physical-dosimetric enabling a dual linear accelerator 3D planning systems for radiotherapy

    International Nuclear Information System (INIS)

    Alfonso, Rodolfo; Martinez, William; Arelis, Lores; Morales, Jorge

    2009-01-01

    The process of commissioning clinical linear accelerator requires a dual comprehensive study of the therapeutic beam parameters, both photons Electron. All information gained by measuring physical and dosimetric these beams must be analyzed, processed and refined for further modeling in computer-based treatment planning (RTPS). Of professionalism of this process will depend on the accuracy and precision of the calculations the prescribed doses. This paper aims to demonstrate availability clinical linear accelerator system-RTPS with late radiotherapy treatments shaped beam of photons and electrons. (author)

  16. Use of VAP3D software in the construction of pathological anthropomorphic phantoms for dosimetric evaluations

    International Nuclear Information System (INIS)

    Lima, Lindeval Fernandes de; Lima, Fernando R.A.

    2011-01-01

    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

  17. Legal verification of the dosimetric instrumentation using for radiation protection in Cuba

    International Nuclear Information System (INIS)

    Walwyn, A.; Morales, J.A.

    1999-01-01

    By April of 1998 the Decree law 183 of Metrology was published at the Gaceta Oficial de la Republica de Cuba. It establishes the principles and general regulations for the organisation and juridical system of the metrological activity in Cuba. In the radiation protection field this legislation promote the establishment of a verification service of radiation measuring instruments used in the practices with radiation sources in the country. The limitations of old Cuban standards of verification related to dosimetric quantities and to the types of instruments for those which these standards are applicable; and in addition, the publication of new international standards that includes the operational quantities used for the measurement of instruments, led to the elaboration of the X and Gamma Radiation Meters Used in Radiation Protection standard. The requirements of metrological aptitude are taken from some test procedures described in the International Electrotechnical Commission (IEC) standards on photon monitoring equipment. The Secondary Standard Dosimetry Laboratory of the Centre for Radiation Protection and Higiene will start the verification service of Radiation Protection instruments. The beginning of the service is an essential element in the improvement of the accuracy of ionisation radiation metrology in Cuba, and have an evident impact in the protection of the occupationally exposed workers, because having the instruments in good technical condition became a legal exigency to the users of ionisation radiation

  18. New calculation of derived limits for the 1960 radiation protection guides reflecting updated models for dosimetry and biological transport

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Watson, S.B.; Nelson, C.B.; Nelson, D.R.; Richardson, A.C.B.; Sullivan, R.E.

    1984-12-01

    This report presents revised values for the radioactivity concentration guides (RCGs), based on the 1960 primary radiation protection guides (RPGs) for occupational exposure (FRC 1960) and for underground uranium miners (EPA 1971a) using the updated dosimetric models developed to prepare ICRP Publication 30. Unlike the derived quantities presented in Publication 30, which are based on limitation of the weighted sum of doses to all irradiated tissues, these RCGs are based on the ''critical organ'' approach of the 1960 guidance, which was a single limit for the most critically irradiated organ or tissue. This report provides revised guides for the 1960 Federal guidance which are consistent with current dosimetric relationships. 2 figs., 4 tabs

  19. Dosimetric predictors of hypothyroidism in oropharyngeal cancer patients treated with intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Chyan, Arthur; Chen, Josephine; Shugard, Erin; Lambert, Louise; Quivey, Jeanne M; Yom, Sue S

    2014-01-01

    Radiation to the neck has long been associated with an elevated risk of hypothyroidism development. The goal of the present work is to define dosimetric predictors of hypothyroidism in oropharyngeal cancer (OPC) patients treated with intensity-modulated radiation therapy. Data for 123 patients, with a median follow up of 4.6 years, were retrospectively analyzed. Patients with elevated thyroid-stimulating hormone levels or with a clinical diagnosis were categorized as hypothyroid. Patient demographic parameters, thyroid volume, mean thyroid dose, the percent of thyroid volume receiving minimum specified dose levels (VxxGy), and the absolute thyroid volume spared from specified dose levels (VSxxGy) were analyzed. Normal-tissue complication probability (NTCP) was also calculated using several recently published models. Thyroid volume and many radiation dosimetric parameters were statistically different in the hypothyroid group. For the patients with initial thyroid volumes of 8 cc or greater, several dosimetric parameters were found to define subgroups at statistically significant lower risk of developing hypothyroidism. Patients with VS45 Gy of at least 3 cc, VS50 Gy at least 5 cc, VS50 Gy at least 6 cc, V50 Gy below 45%, V50 Gy below 55%, or mean thyroid dose below 49 Gy had a 28-38% estimated risk of hypothyroidism at 3 years compared to a 55% risk for the entire study group. Patients with a NTCP of less than 0.75 or 0.8, calculated using recently published models, were also observed to have a lower risk of developing hypothyroidism. Based on long-term follow up data for OPC patients treated with IMRT, we recommend plan optimization objectives to reduce the volume of thyroid receiving over 45 Gy to significantly decrease the risk of developing hypothyroidism. The online version of this article (doi:10.1186/s13014-014-0269-4) contains supplementary material, which is available to authorized users

  20. Preliminary estimate for reinforcement steel quantity in residential buildings

    Directory of Open Access Journals (Sweden)

    Mahamid Ibrahim

    2016-12-01

    Full Text Available The objective of this study was to develop prediction mathematical equations to compute reinforcement steel quantity in traditional residential buildings based on 158 sets of data collected in the West Bank in Palestine. The records related to the quantities were collected from consultancy firms that provide reinforced concrete design services. The data were collected for residential buildings up to four floors. Linear regression analysis was chosen to show the correlation between the included variables. The following variables were used in the regression models: quantity of reinforcement steel (dependent variable, structural element volume (independent variable and floor area (independent variable. Fourteen models were developed; nine models were developed to compute the quantity of reinforcement steel in different structural elements: slabs, beams, columns and footings. The other five models were used to estimate the total steel quantity in a residential building. The coefficient of multiple determination (R2 of the developed models ranged from 0.70 to 0.82. This confirms a good correlation between the dependent and the independent variables. The accuracy of the developed models was tested using the mean absolute percentage error (MAPE test. With MAPE values ranging from 21% to 36%, the results compare favourably with past research that indicated that accuracy between ±25% and ±50% at the early stages is acceptable. The results also show that the models built on structural element size have better accuracy than the models using floor area. Such types of equations are very useful, especially in their simplicity and ability to be handled by calculators or simple computer programmes.

  1. Development of a personalized dosimetric tool for radiation protection in case of internal contamination and targeted radiotherapy in nuclear medicine

    International Nuclear Information System (INIS)

    Chiavassa, S.

    2005-12-01

    Current internal dosimetric estimations are based on the M.I.R.D. formalism and used standard mathematical models. These standard models are often far from a given patient morphology and do not allow to perform patient-specific dosimetry. The aim of this study was to develop a personalized dosimetric tool, which takes into account real patient morphology, composition and densities. This tool, called O.E.D.I.P.E., a French acronym of Tool for the Evaluation of Personalized Internal Dose, is a user-friendly graphical interface. O.E.D.I.P.E. allows to create voxel-based patient-specific geometries and associates them with the M.C.N.P.X. Monte Carlo code. Radionuclide distribution and absorbed dose calculation can be performed at the organ and voxel scale. O.E.D.I.P.E. can be used in nuclear medicine for targeted radiotherapy and in radiation protection in case of internal contamination. (author)

  2. 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.

  3. Study of a new dosimetric radio-thermoluminescent systems

    International Nuclear Information System (INIS)

    Cazac, T.C.

    1980-01-01

    This is the first Romanian study to investigate conditions to obtain the radio-thermo-luminescent systems: MgB 4 O 7 :A(A-Nd,Sm,Eu,Dy,Tb,Dy+Sm and Tb+Sm) MgF 2 A (A=Mn,Dy,Tb,Sm,Li), their essential dosimetric characters, as well as the (MgF 2 =Mn) thermophosphorus mixture with a ( 6 LiF) lithium target. An investigation was developed upon a new category of radio-thermoluminescent detectors with low radiation energy dependence and fading, magnesjum boride activated by several elements of the lanthanides class (Nd,Sm,Eu,Dy,Tb). A new radio-thermoluminescent dosimetric system with high sensitivity and moderate dependence on energy radiation - (Mnsup(2+)) manganese activated magnesium fluoride - was also studied. The author explored application of investigated detectors MgF 2 =Mn, MgB 4 O 7 =Dy and MgB 4 O 7 :Tb in neutron dosimetry in complex gamma-neutron fields. It is deemed that by using the dosimetric systems reported in the thesis in order to measure gamma, beta and neutron radiation doses, dosimetric control can be ensured both in professional dosimetry and in nuclear accident dosimetry, as well as in various basic and applicative investigations. A modest contribution is thus made towards achieving the national nuclear program through an extension of the thermophosphorus range with practical applications in nuclear radiation dosimetry. (author)

  4. A Viewpoint on the Quantity "Plane Angle"

    Science.gov (United States)

    Eder, W. E.

    1982-01-01

    Properties of the quantity "plane angle" are explored under the hypothesis that it is a dimensional quantity. The exploration proceeds especially with respect to the physical concept, its mathematical treatment, vector concepts, measurement theory, units of related quantities, engineering pragmatism, and SI. An attempt is made to bring these different relations into a rational, logical and consistent framework, and thus to justify the hypothesis. Various types of vectorial quantities are recognized, and their properties described with an outline of the necessary algebraic manipulations. The concept of plane angle is amplified, and its interdependence with the circular arc is explored. The resulting units of plane angle form a class of similar scales of measurement. Consequences of the confirmed hypothesis are developed for mathematical expressions involving trigonometric functions, rotational volumes and areas, mathematical limits, differentiation and series expansion. Consequences for mechanical rotational quantities are developed, with proposals for revisions to a number of expressions for derived units within SI. A revised definition for the quantity "plane angle" is stated to take account of the developed insights. There is a clear need to reconsider the status of plane angle and some other quantities within the international framework of SI.

  5. SU-G-TeP3-11: Radiobiological-Cum-Dosimetric Quality Assurance of Complex Radiotherapy Plans

    Energy Technology Data Exchange (ETDEWEB)

    Paudel, N; Narayanasamy, G; Zhang, X; Penagaricano, J; Morrill, S [University of Arkansas for Medical Sciences, Little Rock, AR (United States); Mavroidis, P [University North Carolina, Chapel Hill, NC (United States); Pyakuryal, A [National Cancer Institute, Rockville, MD (United States); Han, E [UT MD Anderson Cancer Center, Houston, TX (United States); Liang, X [University of Florida Health Proton Therapy Institute, Jacksonville, FL (United States); Kim, D [Kyung Hee University Hospital, Seol (Korea, Republic of)

    2016-06-15

    Purpose: Dosimetric gamma-analysis used for QA of complex radiotherapy plans tests the dosimetric equivalence of a delivered plan with the treatment planning system (TPS) optimized plan. It does not examine whether a dosimetric difference results in any radiobiological difference. This study introduces a method to test the radiobiological and dosimetric equivalence between a delivered and the TPS optimized plan. Methods: Six head and neck and seven lung cancer VMAT or IMRT plans optimized for patient treatment were calculated and delivered to an ArcCheck phantom. ArcCheck measured dose distributions were compared with the TPS calculated dose distributions using a 2-D gamma-analysis. Dose volume histograms (DVHs) for various patient structures were obtained by using measured data in 3DVH software and compared against the TPS calculated DVHs using 3-D gamma analysis. DVH data were used in the Poisson model to calculate tumor control probability (TCP) for the treatment targets and in the sigmoid dose response model to calculate normal tissue complication probability (NTCP) for the normal structures. Results: Two-D and three-D gamma passing rates among six H&N patient plans differed by 0 to 2.7% and among seven lung plans by 0.1 to 4.5%. Average ± SD TCPs based on measurement and TPS were 0.665±0.018 and 0.674±0.044 for H&N, and 0.791±0.027 and 0.733±0.031 for lung plans, respectively. Differences in NTCPs were usually negligible. The differences in dosimetric results, TCPs and NTCPs were insignificant. Conclusion: The 2-D and 3-D gamma-analysis based agreement between measured and planned dose distributions may indicate their dosimetric equivalence. Small and insignificant differences in TCPs and NTCPs based on measured and planned dose distributions indicate the radiobiological equivalence between the measured and optimized plans. However, patient plans showing larger differences between 2-D and 3-D gamma-analysis can help us make a more definite conclusion

  6. A geochemical module for "AMDTreat" to compute caustic quantity, effluent quantity, and sludge volume

    Science.gov (United States)

    Cravotta,, Charles A.; Parkhurst, David L.; Means, Brent P; McKenzie, Bob; Morris, Harry; Arthur, Bill

    2010-01-01

    Treatment with caustic chemicals typically is used to increase pH and decrease concentrations of dissolved aluminum, iron, and/or manganese in largevolume, metal-laden discharges from active coal mines. Generally, aluminum and iron can be removed effectively at near-neutral pH (6 to 8), whereas active manganese removal requires treatment to alkaline pH (~10). The treatment cost depends on the specific chemical used (NaOH, CaO, Ca(OH)2, Na2CO3, or NH3) and increases with the quantities of chemical added and sludge produced. The pH and metals concentrations do not change linearly with the amount of chemical added. Consequently, the amount of caustic chemical needed to achieve a target pH and the corresponding effluent composition and sludge volume can not be accurately determined without empirical titration data or the application of geochemical models to simulate the titration of the discharge water with caustic chemical(s). The AMDTreat computer program (http://amd.osmre.gov/ ) is widely used to compute costs for treatment of coal-mine drainage. Although AMDTreat can use results of empirical titration with industrial grade caustic chemicals to compute chemical costs for treatment of net-acidic or net-alkaline mine drainage, such data are rarely available. To improve the capability of AMDTreat to estimate (1) the quantity and cost of caustic chemicals to attain a target pH, (2) the concentrations of dissolved metals in treated effluent, and (3) the volume of sludge produced by the treatment, a titration simulation is being developed using the geochemical program PHREEQC (wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/) that will be coupled as a module to AMDTreat. The simulated titration results can be compared with or used in place of empirical titration data to estimate chemical quantities and costs. This paper describes the development, evaluation, and potential utilization of the PHREEQC titration module for AMDTreat.

  7. Personal dosimetric monitoring in Ukraine: current status and further development

    International Nuclear Information System (INIS)

    Chumak, V. V.; Musijachenkom, A. V.; Boguslavskaya, A. I.

    2003-01-01

    Presently Ukraine has mixed system for dosimetric monitoring. Nuclear power plants and some major nuclear facilities have their own dosimetry services, which are responsible for regular dosimetric monitoring of workers. Rest of occupationally exposed persons is monitored by dosimetry laboratories affiliated to the territorial authorities for sanitary and epidemiology supervision. In 2002-2003 Ukrainian Ministry of Health performed survey of the status of dosimetric monitoring and inventory of critical groups requiring such monitoring. Dosimetry services in Ukraine cover about 38,000 occupationally exposed workers, including 9,100 medical professionals, 16,400 employees of 5 nuclear power plants and ca.12,400 workers dealing with other sources of occupational exposure (industry, research). Territorial dosimetry services operate in 13 of 24 regions of Ukraine, using DTU-01 manual TLD readers produced with one exception in 1988-1990. The coverage of critical groups by dosimetric monitoring is variable and ranges from 38% to 100% depending on the region. Personnel of nuclear power plants (about 16,400 workers) is monitored by their own dosimetry services achieving absolute coverage of the main staff and temporary workers. Current inadequate status of dosimetric monitoring infrastructure in Ukraine demands an urgent elaboration of the united state system for monitoring and recording of individual doses. The proposed plan would allows to bring dosimetry infrastructure in Ukraine to the modern state which would be compatible with existing and future European and international radiation protection networks. Unitary structure of Ukraine, strong administrative command and good communications between regions of the country are positive factors in favour of efficient implementation of the proposed plan. Deficiencies are associated with limited funding of this effort. (authors)

  8. Dosimetric and clinical results of three-dimensional conformal radiotherapy for locally recurrent nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Zheng Xiaokang; Ma Jun; Chen Longhua; Xia Yunfei; Shi Yusheng

    2005-01-01

    Purpose: To assess the dosimetric and clinical results of three-dimensional conformal radiotherapy (3D CRT) for locally recurrent nasopharyngeal carcinoma (NPC). Methods: A total of 86 patients with locally recurrent NPC were retreated with 3D CRT. The median prescribed dose was 68 Gy with 2 Gy per fractionation. Dosimetric quality was evaluated with dose distribution in planning target volume (PTV) and specified organs at risk (OAR), dose conformity index (CI) and dose homogeneity index (HI). The actuarial rate of local failure-free (LFF), overall survival (OS) and major late toxicities (MLT) were estimated with Kaplan-Meier method. Multivariate analysis for prognosis was performed using the Cox regression proportional hazards model. Results: The mean dose to PTV averaged 66.8 Gy, and the dose to specified OAR was acceptable. The average value of CI and HI was 0.59 and 9.1%. The 5-year actuarial rate of LFF and OS was 71 and 40%, respectively. The 5-year actuarial incidence of MLT≥Grade 3 and ≥Grade 4 were 100 and 49%, respectively. The major prognostic factors were T stage and the size of gross tumor volume (GTV). Advanced T stage and large GTV volume were associated with poor LFF and OS and high risk of MLT. Conclusion: The dosimetric quality of 3D CRT for locally recurrent NPC is generally excellent. A relatively high local control was achieved with this technique. However, the incidence of late toxicities were not found to decrease as originally expected. Early diagnosis of the recurrence and reasonable definition of the target volume are crucial to achieve a better outcome

  9. 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)

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

  11. Studies on quantity and composition of dairy cow excreta

    International Nuclear Information System (INIS)

    Peschke, H.

    1982-01-01

    After feeding a lactating dairy cow a day ration completely enriched with 15 N, the quantities of feces and urine were registered over a period of ten days and put into proportion to the animal mass. The fecal dry matter was put into proportion to the dry matter of the fodder by means of 15 N analysis the N excretion with the excreta was determined concerning quantity and time. Selected feces and urine charges were used to produce a slurry model. The content of nutritive elements of the initial components and of the organic fertilizer are discussed. (author)

  12. Quantities and concepts used in radiation dosimetry

    International Nuclear Information System (INIS)

    Carlsson, G.A.; Carlsson, C.A.

    1982-01-01

    Radiation dosimetry is a pure physical science, as fostered by the elegant work of the International Commission on Radiation Units and Measurements (ICRU), in defining the basic quantities and units of dosimetry. Nevertheless, questions concerning the interpretation and application of some quantities still remain. The present work focuses on some of these questions and in particular deals with the quantity fluence which is frequently misunderstood. Radiation dosimetry is closely related to radiation transport theory, and the usefulness of the vectorial quantities used extensively in transport theory is pointed out. It is proposed that vectorial quantities be included in the radiometry considerations of the ICRU. This would contribute to clarifying the basic concepts of dosimetry and promoting its establishment as a physical science. Equations are given for calculating the absorbed dose in various conditions of radiation equilibrium, along with discussions of the quantities needed for their evaluations. These equations are relevant to the important field of cavity theory. Refinements of existing cavity theories, in particular those for photon and electron irradiations, can benefit from a deeper understanding of these equations and the various conditions of equilibrium in which they are valid. (author)

  13. Determination of task group 43 dosimetric parameters for CSM40 137Cs source for use in brachytherapy.

    Science.gov (United States)

    Firoozabadi, Mohammad Mehdi; Jimabadi, Elaheh; Ghorbani, Mahdi; Behmadi, Marziyeh

    2018-03-01

    The CSM40 137 Cs source model is currently being used in clinical brachytherapy. According to the recommendations of task group No. 43 (TG-43) of the American Association of Physicists in Medicine, dosimetry parameters of brachytherapy sources should be determined by two independent investigators before their clinical use. The aim of this study was to determine the TG-43 dosimetry parameters for a medium-dose-rate CSM40 137 Cs source. The determined dosimetric parameters included the air kerma strength, dose rate constant, radial dose function, and anisotropy function. To determine the source's dosimetric parameters, the CSM40 source was stimulated by the Monte Carlo N-Particle MCNP code. The TG-43 parameters were compared with the data of Vijande et al. on this source. The results showed that the dosimetry parameters for this source had good agreement with the results of Vijande et al. The dosimetric parameters of the CSM40 source can be used in treatment-planning systems incorporating this source model. The data can also be used for the quality assurance of treatment-planning systems.

  14. Estimating Historical Landfill Quantities to Predict Methane Emissions

    OpenAIRE

    Lyons, Seán; Murphy, Liam; Tol, Richard S. J.

    2009-01-01

    We estimate Irish historical landfill quantities from 1960 -2008 and Irish methane emissions from 1968-2006. A model is constructed in which waste generation is a function of income, price of waste disposal and, household economies of scale. A transformation ratio of waste to methane is also included in the methane emissions model. Our results contrast significantly with the Irish Environmental Protection Agency's (EPA) figures due to the differences in the underlying assumptions. The EPA's w...

  15. Estimating Historical Landfill Quantities to Predict Methane Emissions

    OpenAIRE

    LYONS, SEAN; TOL, RICHARD

    2009-01-01

    PUBLISHED We estimate Irish historical landfill quantities from 1960 -2008 and Irish methane emissions from 1968-2006. A model is constructed in which waste generation is a function of income, price of waste disposal and, household economies of scale. A transformation ratio of waste to methane is also included in the methane emissions model. Our results contrast significantly with the Irish Environmental Protection Agency's (EPA) figures due to the differences in the underlying assumptions...

  16. Multidemand Multisource Order Quantity Allocation with Multiple Transportation Alternatives

    Directory of Open Access Journals (Sweden)

    Jun Gang

    2015-01-01

    Full Text Available This paper focuses on a multidemand multisource order quantity allocation problem with multiple transportation alternatives. To solve this problem, a bilevel multiobjective programming model under a mixed uncertain environment is proposed. Two levels of decision makers are considered in the model. On the upper level, the purchaser aims to allocate order quantity to multiple suppliers for each demand node with the consideration of three objectives: total purchase cost minimization, total delay risk minimization, and total defect risk minimization. On the lower level, each supplier attempts to optimize the transportation alternatives with total transportation and penalty costs minimization as the objective. In contrast to prior studies, considering the information asymmetry in the bilevel decision, random and fuzzy random variables are used to model uncertain parameters of the construction company and the suppliers. To solve the bilevel model, a solution method based on Kuhn-Tucker conditions, sectional genetic algorithm, and fuzzy random simulation is proposed. Finally, the applicability of the proposed model and algorithm is evaluated through a practical case from a large scale construction project. The results show that the proposed model and algorithm are efficient in dealing with practical order quantity allocation problems.

  17. 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.

  18. Dosimetric improvements following 3D planning of tangential breast irradiation

    International Nuclear Information System (INIS)

    Aref, Amr; Thornton, Dale; Youssef, Emad; He, Tony; Tekyi-Mensah, Samuel; Denton, Lori; Ezzell, Gary

    2000-01-01

    Purpose: To evaluate the dosimetric difference between a simple radiation therapy plan utilizing a single contour and a more complex three-dimensional (3D) plan utilizing multiple contours, lung inhomogeneity correction, and dose-based compensators. Methods and Materials: This is a study of the radiation therapy (RT) plans of 85 patients with early breast cancer. All patients were considered for breast-conserving management and treated by conventional tangential fields technique. Two plans were generated for each patient. The first RT plan was based on a single contour taken at the central axis and utilized two wedges. The second RT plan was generated by using the 3D planning system to design dose-based compensators after lung inhomogeneity correction had been made. The endpoints of the study were the comparison between the volumes receiving greater than 105% and greater than 110% of the reference dose, as well as the magnitude of the treated volume maximum dose. Dosimetric improvement was defined to be of significant value if the volume receiving > 105% of one plan was reduced by at least 50% with the absolute difference between the volumes being 5% or greater. The dosimetric improvements in 49 3D plans (58%) were considered of significant value. Patients' field separation and breast size did not predict the magnitude of improvement in dosimetry. Conclusion: Dose-based compensator plans significantly reduced the volumes receiving > 105%, >110%, and volume maximum dose.

  19. 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 γ-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.

  20. 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.

  1. Editorial: New operational dose equivalent quantities

    International Nuclear Information System (INIS)

    Harvey, J.R.

    1985-01-01

    The ICRU Report 39 entitled ''Determination of Dose Equivalents Resulting from External Radiation Sources'' is briefly discussed. Four new operational dose equivalent quantities have been recommended in ICRU 39. The 'ambient dose equivalent' and the 'directional dose equivalent' are applicable to environmental monitoring and the 'individual dose equivalent, penetrating' and the 'individual dose equivalent, superficial' are applicable to individual monitoring. The quantities should meet the needs of day-to-day operational practice, while being acceptable to those concerned with metrological precision, and at the same time be used to give effective control consistent with current perceptions of the risks associated with exposure to ionizing radiations. (U.K.)

  2. Calibration of personal dosimeters: Quantities and terminology

    International Nuclear Information System (INIS)

    Aleinikov, V.E.

    1999-01-01

    The numerical results obtained in the interpretation of individual monitoring of external radiation depend not only on the accurate calibration of the radiation measurement instruments involved, but also on the definition of the quantities in term of which these instruments are calibrated The absence of uniformity in terminology not only makes it difficult to understand properly the scientific and technical literature but can also lead to incorrect interpretation of particular concepts and recommendations. In this paper, brief consideration is given to definition of radiation quantities and terminology used in calibration procedures. (author)

  3. 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,…

  4. 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... part, transport or receive for transportation to any foreign destination, a shipment of 25 packages or...

  5. 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…

  6. Quantity, resolution and syllable geometry | Lass | Stellenbosch ...

    African Journals Online (AJOL)

    Stellenbosch Papers in Linguistics. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 10 (1983) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Quantity, resolution and syllable geometry. R Lass. Abstract.

  7. Varieties of Quantity Estimation in Children

    Science.gov (United States)

    Sella, Francesco; Berteletti, Ilaria; Lucangeli, Daniela; Zorzi, Marco

    2015-01-01

    In the number-to-position task, with increasing age and numerical expertise, children's pattern of estimates shifts from a biased (nonlinear) to a formal (linear) mapping. This widely replicated finding concerns symbolic numbers, whereas less is known about other types of quantity estimation. In Experiment 1, Preschool, Grade 1, and Grade 3…

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

    African Journals Online (AJOL)

    1991-01-01

    Jan 1, 1991 ... perceptions regarding the importance of CPD as well as relating evidence to various aspects of CPD, as drawn ... records on time as the most important factor when participating in CPD. It was found that quantity ..... interpersonal communication skills, while others might be lacking in one or more of these ...

  9. 30 CFR 75.325 - Air quantity.

    Science.gov (United States)

    2010-07-01

    ... coal by simply energizing the equipment on the section. (c) In longwall and shortwall mining systems... utilizing diesel-powered equipment in underground coal mines shall submit to the appropriate MSHA district... SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.325 Air quantity. (a)(1) In bituminous and...

  10. The role of the Secondary Laboratory of Dosimetric calibration in the implementation of the dosimetric magnitudes with radiological protection aims

    International Nuclear Information System (INIS)

    Perez Medina O, V.; Alvarez R, J.T.; Tovar M, V.M.

    2006-01-01

    It is very well-known the paper of the net of secondary laboratories of dosimetric calibration of the OAS in the dissemination of the traceability of the dosimetric magnitudes: kerma in air and absorbed dose in water, to the radiotherapy departments, given the high accuracy and precision that require the radiotherapy treatments. However the LSCD has other important areas at least for the development, implementation and evaluation of dosimetric magnitudes denominated operative magnitudes with ends of radiological protection: environmental equivalent dose H*(10), directional equivalent dose H'(0.07) and personal equivalent dose Hp. In the case of radiological protection the LSCD-ININ has been implementing the infrastructure to give service of personal dosimetry for photons and beta particles in terms of the operative magnitudes. For photons: X and gamma rays, it account with a secondary pattern camera PTW T34035 gauged in H * and Hp in the primary laboratory of Germany PTB. For the case of beta radiation its account with an extrapolation camera PTW 23392 with a secondary pattern kit of sources of the type I, gauged in terms of H'(0.07) in the PTB. (Author)

  11. SU-F-T-240: EPID-Based Quality Assurance for Dosimetric Credentialing

    Energy Technology Data Exchange (ETDEWEB)

    Miri, N [University of Newcastle, Newcastle, NSW (Australia); Lehmann, J [Calvary Mater Newcastle, Newcastle, NSW (Australia); Vial, P [Liverpool Hospital, Sydney, NSW (Australia); Greer, P [Calvary Mater Newcastle, Newcastle, NSW (Australia); University of Newcastle, Newcastle, NSW (Australia)

    2016-06-15

    Purpose: We propose a novel dosimetric audit method for clinical trials using EPID measurements at each center and a standardized EPID to dose conversion algorithm. The aim of this work is to investigate the applicability of the EPID method to different linear accelerator, EPID and treatment planning system (TPS) combinations. Methods: Combination of delivery and planning systems were three Varian linacs including one Pinnacle and two Eclipse TPS and, two ELEKTA linacs including one Pinnacle and one Monaco TPS. All Varian linacs had the same EPID structure and similarly for the ELEKTA linacs. Initially, dose response of the EPIDs was investigated by acquiring integrated pixel value (IPV) of the central area of 10 cm2 images versus MUs, 5-400 MU. Then, the EPID to dose conversion was investigated for different system combinations. Square field size images, 2, 3, 4, 6, 10, 15, 20, 25 cm2 acquired by all systems were converted to dose at isocenter of a virtual flat phantom then the dose was compared to the corresponding TPS dose. Results: All EPIDs showed a relatively linear behavior versus MU except at low MUs which showed irregularities probably due to initial inaccuracies of irradiation. Furthermore, for all the EPID models, the model predicted TPS dose with a mean dose difference percentage of 1.3. However the model showed a few inaccuracies for ELEKTA EPID images at field sizes larger than 20 cm2. Conclusion: The EPIDs demonstrated similar behavior versus MU and the model was relatively accurate for all the systems. Therefore, the model could be employed as a global dosimetric method to audit clinical trials. Funding has been provided from Department of Radiation Oncology, TROG Cancer Research and the University of Newcastle. Narges Miri is a recipient of a University of Newcastle postgraduate scholarship.

  12. Provider-client interactions and quantity of health care use.

    Science.gov (United States)

    Lien, Hsien-Ming; Albert Ma, Ching-To; McGuire, Thomas G

    2004-11-01

    This paper considers three types of provider-client interactions that influence quantity of health care use: rationing, effort, and persuasion. By rationing, we refer to a quantity limit set by a provider; effort, the productive inputs supplied by a provider to increase a client's demand; persuasion, the unproductive inputs used by a provider to induce a client's demand. We construct a theoretical model incorporating all three mechanisms as special cases. When the general model is specialized into one of three mechanisms, a set of empirical implications emerges. We test for the presence of each mechanism using data of patients receiving outpatient treatment for alcohol abuse in the Maine Addiction Treatment System. We find evidence for rationing and persuasion, but not effort.

  13. Complexity in an Unexpected Place: Quantities in Selected Acquisition Reports

    Science.gov (United States)

    2017-12-01

    no general- purpose predictive models for program cost growth have been identified. The Congressional Budget Office applies generic cost growth... information at the program level. For example, no other annual submission can tell OSD or the Congress about the projected procurement costs for a...Unit Costs from the “ Cost Quantity Information ” Section of the December 2015 SAR Figure 3 shows four ships of the Arleigh Burke class. The visible

  14. Return handling options and order quantities for single period products

    OpenAIRE

    Vlachos, D.; Dekker, R.

    2000-01-01

    textabstractProducts which are sold through E-commerce or mail sales catalogues tend to have a much higher return rate than traditional products. The returns are especially problematic for seasonal products. To support decision making in these situations we study various options, which may be considered as strategic decisions, on handling the increased return flow. Closed form analytic expressions for optimal order quantities are obtained by solving the models developed for each option. Decis...

  15. Development of NTCP models for head and neck cancer patients treated with three-dimensional conformal radiotherapy for xerostomia and sticky saliva: The role of dosimetric and clinical factors

    International Nuclear Information System (INIS)

    Beetz, Ivo; Schilstra, Cornelis; Burlage, Fred R.; Koken, Phil W.; Doornaert, Patricia; Bijl, Henk P.; Chouvalova, Olga; Leemans, C. René; Bock, Geertruida H. de; Christianen, Miranda E.M.C.; Laan, Bernard F.A.M. van der; Vissink, Arjan; Steenbakkers, Roel J.H.M.; Langendijk, Johannes A.

    2012-01-01

    Purpose: The purpose of this multicentre prospective study was to investigate the significance of the radiation dose in the major and minor salivary glands, and other pre-treatment and treatment factors, with regard to the development of patient-rated xerostomia and sticky saliva among head and neck cancer (HNC) patients treated with primary (chemo-) radiotherapy ((CH)RT). Methods and materials: The study population was composed of 167 consecutive HNC patients treated with three-dimensional conformal (3D-CRT) (CH) RT. The primary endpoint was moderate to severe xerostomia (XER6m) as assessed by the EORTC QLQ-H and N35 at 6 months after completing (CH)RT. The secondary endpoint was moderate to severe sticky saliva at 6 months (STIC6 m). All organs at risk (OARs) potentially involved in salivary function were delineated on planning-CT, including the parotid, submandibular and sublingual glands and the minor glands in the soft palate, cheeks and lips. Patients with moderate to severe xerostomia or sticky saliva at baseline were excluded. The optimum number of variables for a multivariate logistic regression model was determined using a bootstrapping method. Results: The multivariate analysis showed the mean parotid dose, age and baseline xerostomia (none versus a bit) to be the most important predictors for XER6m. The risk of developing xerostomia increased with age and was higher when minor baseline xerostomia was present in comparison with patients without any xerostomia complaints at baseline. Model performance was good with an area under the curve (AUC) of 0.82. For STIC6m, the mean submandibular dose, age, the mean sublingual dose and baseline sticky saliva (none versus a bit) were most predictive for sticky saliva. The risk of developing STIC6 m increased with age and was higher when minor baseline sticky saliva was present in comparison with patients without any sticky saliva complaints at baseline. Model performance was good with an AUC of 0.84. Conclusions

  16. Calculational evaluations of the proposal for a reference dosimetric phantom for BNCT

    International Nuclear Information System (INIS)

    Bjugg, H.; Seppaelae, T.; Auterinen, I.; Kotiluoto, P.; Savolainen, S.

    2001-01-01

    Standard dosimetric phantoms are used in radiotherapy to compare irradiations under standard conditions. They provide volumes of tissue substitute for the measurement of absorbed dose and are large enough to ensure that full contribution to the absorbed dose from scattered radiation is received at the point of measurement. Aim of this study was to find out a recommendation for the boundary values of size of a reference phantom. These reference conditions for the reference measurement methods are created for 'A code of practise for dosimetry, of BNCT in Europe' project. The major objective of the project is to prepare detailed guidelines for the dosimetry of epithermal neutron beams to be used for treatment of cancer patients by Boron Neutron Capture Therapy (BNCT) at European research reactors and accelerators. For this objective Monte Carlo simulations have been carried out with MCNP 4B code in three different cubic phantoms for studying effect of different phantom sizes in important radiation components. These three phantoms are the proposed reference (measurement) phantom (20*20*20 cm), a phantom that was assumed to model an infinite phantom, and a smaller (15*15*15 cm) cubic phantom which exists in Petten BNCT facility in Netherlands. Function of the smallest phantom was to study acceptable lower limit to the phantom size to still reach the reference conditions. All the simulated phantoms were cubic water phantoms with one 0.5 cm thick (beam side) wall and three 1 cm thick walls of PMMA (polymethyl-methacrylate). The comparisons were done with calculations of the thermal, epithermal and fast neutron fluence rates in analogous points. The source specification of the MCNP runs were accordance of 250 kW FiR 1 research reactor neutron beam with 14 cm beam aperture. In order to minimise the statistical error of the Monte Carlo calculations, over 60*106 source particles were simulated for infinite and reference phantom cases. Calculation results were in good

  17. Strategic Planning in Irish Quantity Surveying Pracitces

    OpenAIRE

    Murphy, Roisin

    2011-01-01

    The role and usefulness of strategic planning has been well documented over several decades of strategic management research. Despite the significant body of existing knowledge in the field of strategic planning, there remains a paucity of investigation into the construction sector, specifically in Professional Service Firms (PSF’s) operating within it. The aim of this research was to ascertain the type, scope and extent of strategic planning within Irish Quantity Surveying (QS) practices and...

  18. Enzyme catalysis with small ionic liquid quantities.

    Science.gov (United States)

    Fischer, Fabian; Mutschler, Julien; Zufferey, Daniel

    2011-04-01

    Enzyme catalysis with minimal ionic liquid quantities improves reaction rates, stereoselectivity and enables solvent-free processing. In particular the widely used lipases combine well with many ionic liquids. Demonstrated applications are racemate separation, esterification and glycerolysis. Minimal solvent processing is also an alternative to sluggish solvent-free catalysis. The method allows simplified down-stream processing, as only traces of ionic liquids have to be removed.

  19. On pure-strategy Nash equilibria in price-quantity games

    NARCIS (Netherlands)

    Bos, I.; Vermeulen, A.J.

    2015-01-01

    This paper examines the existence and characteristics of pure-strategy Nash equilibria in oligopoly models in which firms set both prices and quantities. Existence is proved for a broad and natural class of price-quantity games. With differentiated products, the equilibrium outcome is similar to

  20. 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)

  1. Pediatric phantoms for use in dosimetric calculations

    International Nuclear Information System (INIS)

    Shoup, R.L.; Hwang, J.L.; Poston, J.W.; Warner, G.G.

    1976-01-01

    Estimating absorbed doses to children from external and internal radiation sources has become important to the nuclear industry and pediatric nuclear medicine. The Medical Physics and Internal Dosimetry Section at ORNL has recently completed the design of mathematical representations of children of ages newborn, 1 year, and 5 years old. These mathematical representations will be referred to as pediatric phantoms. Using these phantoms, relevant energy deposition data have been developed which establish a meaningful model for use in estimating radiation dose to children

  2. 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.

  3. Dosimetric study in iodine-125 seeds for brachytherapy application

    International Nuclear Information System (INIS)

    Zeituni, Carlos Alberto

    2008-01-01

    The demand for iodine-125 seeds for use in brachytherapy treatments has experienced an increase along recent years in Brazil and all over the world. All iodine-125 seed must have its operational parameters measured and/or calculated every time changes in the production process are carried out. A complete dosimetric measurement is very expensive, and it is recommended that this procedure must be repeated at least once a year. Thus, this work developed a methodology for the entire dosimetric process. This methodology is based on the scarce information available in the literature, once almost all the methodology used in large industrial laboratories is commercial secret. The proposed methodology was tested using seeds of Amersham-Oncura-Ge Healthcare, which is the largest seed manufactory in the world. In this new methodology, an automatic reader was employed in order to reduce the time required in the selection process of the TLD-100 dosimeters used and a postprocessing of the obtained spectra was carried out. A total of 142 dosimeters were used and only 29 have been selected using the new methodology. Measurements were performed using slabs of Solid Water RW1 to simulate measuring in the 'water', using three different experimental apparatus and each measurement was repeated at least three times. The TLD-100 calibration was performed using a Dermopan II - Siemens. The measured values showed a good agreement with the ones available in the literature. Finally, these measured values were compared with calculated ones obtained by a semiempirical simulation program, showing a good agreement and, therefore, demonstrating the validity of the proposed methodology regarding dosimetric calculations. (author)

  4. 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

  5. Radiation exposure of the patient in diagnostic nuclear medicine. Experimental studies of the biokinetics of 111In-DTPA-D-Phe1-octreotide, 99mTc-MIBI, 14C-triolein and 14C-urea, and development of dosimetric models

    International Nuclear Information System (INIS)

    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 111 In-DTPA-D-Phe 1 -octreotide (for diagnosis of neuroendocrine tumours) and 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. 111 In-DTPA-D-Phe 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). 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 14 CO 2 , in exhaled air from patients undergoing 14 C-breath tests, with special application to 14 C-triolein (for study of fat malabsorption). AMS was proven to be a useful technique for long-term retention studies of 14 C, and was used together with liquid scintillation counting in an investigation of the biokinetics of 14 C-urea in adult and paediatric patients (for diagnosis of Helicobacter pylori infection in the upper gastrointestinal tract). The effective dose for 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, resulting in an effective dose of approximately 0.002 mSv per

  6. 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.

  7. Dosimetric confirmation of a software for the design of radiotherapy

    International Nuclear Information System (INIS)

    Alfonso, R.; Huerta, U.; Torres, M.; Alonso, J.L.

    1995-01-01

    A software for radiotherapy treatment has been recently designed by specialists in medical physics form Hermanos Ameijeiras Clinical and Surgical Hospital. Several locations in the distributions of dose calculations. The results of dosimetric measurements with TLD-700 powder in a human-like manikin were taken as reference. The different options available for the entry of patients shape data are explained. A comparison of the results of measurements with calculations, is presented. Causes of discrepancies are analyzed and recommendations regarding the usefulness of the different for the collection of data from patients are made

  8. Radioecological and dosimetric consequences of Chernobyl accident in France

    International Nuclear Information System (INIS)

    Renaud, Ph.; Beaugelin, K.; Maubert, H.; Ledenvic, Ph.

    1997-01-01

    After ten years and the taking in account of numerous data, it can be affirmed that the dosimetric consequences of Chernobyl accident will have been limited in France. for the period 1986-2046, the individual middle efficient dose commitment, for the area the most reached by depositing is inferior to 1500 μSv, that represents about 1% of middle natural exposure in the same time. but mountains and forests can have more important surface activities than in plain. Everywhere else, it can be considered that the effects of Chernobyl accident are disappearing. the levels of cesium 137 are now often inferior to what they were before the accident. (N.C.)

  9. Dosimetric evaluation of Radiotherapy units wit 60Co

    International Nuclear Information System (INIS)

    Leon, B. Salinas de; Tovar M, V.; Becerril V, A.

    2000-01-01

    The SSDL network of the IAEA performs, every year, quality audit tests for radiotherapy services ( 60 Co units and linear accelerators), and for national SSDL as well. Because of the SSDL-Mexico results in these tests and due to our enthusiasm and confidence in our work, a parallel test has been done , which is described in this talk as well as the results. Nowadays, a second parallel test goes up, which could confirm our optimism and open the possibility to our country to start a national dosimetric audit of 60 Co radiotherapy units. (Author)

  10. The pitfalls of dosimetric commissioning for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Tohyama, Naoki; Kodama, Takashi; Hatano, K.

    2013-01-01

    Intensity modulated radiation therapy (IMRT) allows higher radiation dose to be focused to the target volumes while minimizing the dose to OAR. To start of clinical treatment in IMRTvwe must perform commissioning strictly than 3D-conformal radiotherapy (CRT). In this report, pitfalls of dosimetric commissioning for intensity modulated radiation therapy were reviewed. Multileaf collimator (MLC) offsets and MLC transmissions are important parameters in commissioning of RTPS for IMRT. Correction of depth scaling and fluence scaling is necessary for dose measurement using solid phantom. (author)

  11. First approval procedure of the TL dosimetric service of the NPP in Slovenia

    International Nuclear Information System (INIS)

    Janzekovic, H.; Krizman, M.; Pucelj, B.; Stuhec, M.; Zdesar, U.

    2001-01-01

    The individual dosimetry of exposed workers in a NPP is one of the essential parts which demonstrates the radiation protection standards achieved in a facility. According to the current legislation the Ministry of Health of the Republic of Slovenia has the authority to grant approvals to personal dosimetric services which perform the dosimetric monitoring of workers in Slovenia. Due to the fact that the detailed approval procedure is not given in national regulations, the Ministry of Health in 2000 established a group of experts with the task to prepare technical and organising requirements for such approval. Based on international documents [1,2,3] the Approval procedure for the thermoluminescence dosimetric (TL) services was created. Following this procedure the assessment of the TL dosimetric service in the NPP was performed. The problems related to the technical and organising requirements with the emphasise on the QA/QC criteria of the TL dosimetric service will be discussed.(author)

  12. Dosimetric studies, spectrometric, radiographic, metallographic of a new argentinean seed of 125 I used in brachytherapy

    International Nuclear Information System (INIS)

    Pirchio, R.; Saravi, M.; Banchik, D.; Munoz, C.

    2006-01-01

    A new source of 125 I model Braquibac TM has been developed in Argentina for applications in interstitial brachytherapy. The AAPM Task Group 43 (TG-43) recommends that dosimetric characteristics of new sources of brachytherapy of Iodine-125 have been theoretically and experimentally determined before its clinical use. The objectives outlined in this work were the study of the design of the new seed, the calculation of dosimetric parameters and the photons spectra analysis. Its were carried out radiographic and metallographic studies to determine the physical characteristics of the source. For the realization of the dosimetric calculations it was used the Monte Carlo code MCNP5. Values of the radial dose function, g(r), of the constant of dose rate, Λ, of the function of anisotropy of two dimensions, F(r, θ), of the factor and constant of anisotropy its were obtained simulating the source in water according to the recommended methodology in TG-43. The constant of dose rate is similar to 0,880 ± 0,080 c Gy h -1 U -1 . The kerma in air rate of reference, S K , was calculated as 1,036 c Gy cm 2 h -1 mCi -1 simulating the seed in dry air. Its were carried out spectrometric studies using a semiconductor planar detector of HPGe (high purity germanium). Photons spectra showed characteristic x-rays of 125 I with energies of 27,20 keV, 27,47 keV, 31 keV and 31,70 keV gamma photons of 35,5 keV, and x-ray fluorescent coming from the silver nucleus of 22,10 keV, 24,94 keV and 25,45 keV. The angular dependence of the intensity of photons around the seed and in air it was analyzed with the planar detector. This was carried out to study the anisotropy in the photons flow due to variation in the thickness of the titanium wall and of the welding, movements of the silver tube inside the source and deposition of the radioactive material on the silver tube. (Author)

  13. Dosimetric measurements and dose calculation in certain routine studies with different computed tomography units

    International Nuclear Information System (INIS)

    Calzado, A.; Rodriguez, R.; Lopez, M.

    1998-01-01

    The European Commission recently published a White Paper proposing reference values of dosimetric magnitude for several types of CT studies. The objective of the present report is to characterize, in terms of dosimetry, a Ct unit and establish reference values for the doses used in CT in Spain. We took dosimetric measurements in 15 models of the CT Pace line, analyzing the data obtained in patients subjected to brain, chest, abdomen and lumbar spine CT with these units. The CT dose indices (CTDI) for theoretic thicknesses of 2 to 10 mm were 0.094 to 0.098 mGy/mA.s (body phantom) and 0.203 to 0.205 mGy/mA.s (head phantom), and the values for a 1 mm thickness were 0.134 mGy/mA.s (body) and 0.260 mGy/mA.s (head). In patient studies, the following values were found: the weighted CT dose (CTDIw) ranged from 44 to 74 mGy for brain, 27 to 48 mGy in chest, 19 to 33 mGy in lumbar spine and 21 to 33 mGy in abdomen: the dose-length product (DLP) was 499 to 918 mGy.cm in brain studies, 446 to 765 mGy.cm in chest, 188 to 333 mGy.cm in spine and 406 to 613 mGy.cm in abdomen. The effective dose (E) was 1.09 to 2.14 mSv in brain, 7.13 to 12 mSv in chest, 3.16 to 4.97 mSv in lumbar spine and 6.95 to 8.76 mSv in abdomen. The units analyzed processes similar dosimetric behaviors except for certain differences when 1 mm-thick sections were used. With respect to patient dose, the CTDIw, DLP and E obtained in our series were very similar, equal to or greater than the reference values proposed by the European paper. Thus, efforts should be made to optimize CT tests for the purpose of reducing the dose. According to our results, there is a lack of correlation between the values proposed in the document in question for CTDIw and the DLP, suggesting. (Author) 13 refs

  14. The Acquisition of Quantity Contrasts in Guina-ang Bontok

    Science.gov (United States)

    Aoyama, Katsura; Reid, Lawrence A.

    2016-01-01

    This study reports on the acquisition of quantity contrasts in Guina-ang Bontok, an indigenous language spoken in the Philippines. Four-year-old and 5-year-old children's perception and production of quantity contrasts were examined using a pair of names that contrast in the quantity of the medial nasal. Frequencies of the quantity contrast were…

  15. 7 CFR 61.102 - Determination of quantity index.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Determination of quantity index. 61.102 Section 61.102... quantity index. The quantity index of cottonseed shall be determined as follows: (a) For upland cottonseed the quantity index shall equal four times percentage of oil plus six times percentage of ammonia, plus...

  16. 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.

  17. 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.

  18. Evaluation of influence quantities in the semiconductor dosemeters calibration;Avaliacao de grandezas de influencia na calibracao de dosimetros semicondutores

    Energy Technology Data Exchange (ETDEWEB)

    Petri, Anna R. [Pontificia Universidade Catolica (PUC/SP), Sao Paulo, SP (Brazil). Curso de Fisica Medica; Terini, Ricardo A. [Pontificia Universidade Catolica (PUC/SP), Sao Paulo, SP (Brazil). Dept. de Fisica; Pereira, Marco A.G. [Universidade de Sao Paulo (IEE/USP), SP (Brazil). Inst. de Eletrotecnica e Energia

    2009-07-01

    Semiconductor dosimeters are an alternative to the ionization chambers in diagnostic radiology, because they do not require corrections for atmospheric pressure, are rigid and produces a more large signal than ionization chambers. However, these dosimeters, in general, exhibit strong energy dependence. To perform the calibration of dosimeters it has been adopted, in this work, the 'substitution method', proposed by International Atomic Energy Agency (IAEA) in document TRS number 457. In this method, the air kerma rate measured by the dosimeter to be calibrated is compared with that of an ionization chamber previously calibrated for standard X-ray beams. The present study describes the results concerning the 'substitution method' implementation for semiconductor detectors calibration and the influence quantities evaluation in the calibration of dosimetric systems (detector and electrometer). (author)

  19. Dosimetric analysis of BNCT - Boron Neutron Capture Therapy - coupled to 252Cf brachytherapy

    International Nuclear Information System (INIS)

    Brandao, Samia F.; Campos, Tarcisio P.R.

    2009-01-01

    The incidence of brain tumors is increasing in world population; however, the treatments employed in this type of tumor have a high rate of failure and in some cases have been considered palliative, depending on histology and staging of tumor. Its necessary to achieve the control tumor dose without the spread irradiation cause damage in the brain, affecting patient neurological function. Stereotactic radiosurgery is a technique that achieves this; nevertheless, other techniques that can be used on the brain tumor control must be developed, in order to guarantee lower dose on health surroundings tissues other techniques must be developing. The 252 Cf brachytherapy applied to brain tumors has already been suggested, showing promising results in comparison to photon source, since the active source is placed into the tumor, providing greater dose deposition, while more distant regions are spared. BNCT - Boron Neutron Capture Therapy - is another technique that is in developing to brain tumors control, showing theoretical superiority on the rules of conventional treatments, due to a selective irradiation of neoplasics cells, after the patient receives a borate compound infusion and be subjected to a epithermal neutrons beam. This work presents dosimetric studies of the coupling techniques: BNCT with 252 Cf brachytherapy, conducted through computer simulation in MCNP5 code, using a precise and well discretized voxel model of human head, which was incorporated a representative Glioblastoma Multiform tumor. The dosimetric results from MCNP5 code were exported to SISCODES program, which generated isodose curves representing absorbed dose rate in the brain. Isodose curves, neutron fluency, and dose components from BNCT and 252 Cf brachytherapy are presented in this paper. (author)

  20. Study of dosimetric parameters for iodine-125 brachytherapy sources development from IPEN-CNEN/SP using Monte Carlo method

    International Nuclear Information System (INIS)

    Oliveira, Tiago Batista de

    2016-01-01

    Expectations of the World Health Organization for the year 2030 are that the number of cancer deaths is approximately 13.2 million, reflecting the high proportion of this disease in global health issue. With respect to prostate cancer, according to the National Cancer Institute, the number of cases diagnosed worldwide in 2012 was approximately 1.1 million, while in Brazil the data demonstrated the incidence of 68,000 new cases. The treatment of cancer can be performed with surgery (prostatectomy) or radiation therapy. Among radiotherapy, we can highlight the brachytherapy technique, which consists in the introduction of small radioactive sources (seeds) within the prostate, which is delivered a high dose value in the treatment volume and low dose in the surrounding tissues. In Brazil, the medical profession estimates a demand of approximately 8000 seeds / month, and the unit cost of each seed at least US $ 26.00. The AAPM protocol TG-43 recommend the dose-rate constant, radial dose function and anisotropy function for dosimetric analysis LDR brachytherapy seeds. In this work, Monte Carlo simulations were performed in order to assess the dosimetric parameters of the OncoSeed-6711, manufactured by Oncura-GEHealthcare, and a seed developed by Radiation Technology Center, using the MCNP5 code. A 6711 seed, an IPEN seed and the 30 x 30 x 30cm 3 phantom filled with water were modeled to simulate the dose distribution. The 6711 seed parameters were compared with literature, and the results presented relative error less than 0.1% for Λ. In comparison with the 6711 seed, the IPEN model seed dosimetric parameters were similar, account the statistical uncertainty. (author)

  1. Dosimetric pens: evaluation of calibration results in the Laboratorio Nacional de Metrologia das Radiacoes Ionizantes do Instituto de Radioprotecao e Dosimetria (IRD/LNMRI), RJ, Brazil

    International Nuclear Information System (INIS)

    Quaresma, D.S.; Ramos, M.M.O.; Cabral, T.S.; Peixoto, J.G.P.

    2005-01-01

    Dosimetric pens are direct reading personal dosemeters that are used in the practices of radiation protection in industries, hospitals, universities, and research institutes in the country. Quality control of measurements made with these instruments must include their periodical calibration in one of the laboratories of the Calibration Laboratory Network for Ionizing Radiation with the aim to compare the behavior of the measurements made in dosimetric pens of different models and manufacturers, submitted for calibration in the LNMRI/IRD/CNEN (Brazilian Lab for Metrology of Ionizing Radiations of the Institute for Radioprotection and Dosimetry of the Brazilian Nuclear Energy Commission), RJ or national reference laboratory and a member of the Network, in the years of 2000 to 2002. The parameters considered for the purpose of this work were: accuracy and linearity of response and measurement uncertainty evaluated. The results show that among the analyzed models there are changes in behavior

  2. SU-G-BRB-05: Automation of the Photon Dosimetric Quality Assurance Program of a Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lebron, S; Lu, B; Yan, G; Li, J; Liu, C [University of Florida, Gainesville, FL (United States)

    2016-06-15

    Purpose: To develop an automated method to calculate a linear accelerator (LINAC) photon radiation field size, flatness, symmetry, output and beam quality in a single delivery for flattened (FF) and flattening-filter-free (FFF) beams using an ionization chamber array. Methods: The proposed method consists of three control points that deliver 30×30, 10×10 and 5×5cm{sup 2} fields (FF or FFF) in a step-and-shoot sequence where the number of monitor units is weighted for each field size. The IC Profiler (Sun Nuclear Inc.) with 5mm detector spacing was used for this study. The corrected counts (CCs) were calculated and the locations of the maxima and minima values of the first-order gradient determined data of each sub field. Then, all CCs for each field size are summed in order to obtain the final profiles. For each profile, the radiation field size, symmetry, flatness, output factor and beam quality were calculated. For field size calculation, a parameterized gradient method was used. For method validation, profiles were collected in the detector array both, individually and as part of the step-and-shoot plan, with 9.9cm buildup for FF and FFF beams at 90cm source-to-surface distance. The same data were collected with the device (plus buildup) placed on a movable platform to achieve a 1mm resolution. Results: The differences between the dosimetric quantities calculated from both deliveries, individually and step-and-shoot, were within 0.31±0.20% and 0.04±0.02mm. The differences between the calculated field sizes with 5mm and 1mm resolution were ±0.1mm. Conclusion: The proposed single delivery method proved to be simple and efficient in automating the photon dosimetric monthly and annual quality assurance.

  3. 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.

  4. Net present value analysis of the economic production quantity

    OpenAIRE

    Disney, Stephen Michael; Warburton, R. D. H.; Zhong, Q. C.

    2013-01-01

    Using Laplace transforms we extend the economic production quantity (EPQ) model by analysing cash flows from a net present value (NPV) viewpoint. We obtain an exact expression for the present value of the cash flows in the EPQ problem. From this, we are able to derive the optimal batch size. We obtain insights into the monotonicity and convexity of the present value of each of the cash flows, and show that there is a unique minimum in the present value of the sum of the cash flows in the exte...

  5. Method of Converting Wheat Flour Quantity into Rice Flour Quantity in Cookies (Part-1)

    OpenAIRE

    村田,美穂子; 髙橋,由加

    2016-01-01

    A method of converting the wheat flour quantity of a recipe of wheat-flour cookies into the rice flour quantity of a recipe of rice-flour cookies used domestically for wheat-allergic children was studied. The proportion of the water content with respect to the flour content (the wheat or rice flour content) in cut cookies prepared according to a commercially available recipe was obtained. Next, four types of rice-flour cookies were prepared according to a recipe for wheat-flour cookies using ...

  6. 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...

  7. Production of LiF films for dosimetric thermoluminescence application

    International Nuclear Information System (INIS)

    Mauricio, Claudia Lucia de Pinho

    2000-12-01

    This work studies the LiF monolayer and multilayer polycrystalline film's dosimetric properties. The films were produced by electron beam evaporation technique in aluminium and stainless steel substrates maintained at several temperatures. As dosimetric variable, the intensity of the thermoluminescent (TL) glow curve of the films was used. effects of the substrate type and temperature; of the addition of layers of Mg F 2 NaF and Cu F 2 to the LiF films; and of thermal treatments in the TL response of the produced films were studied. The microstructural characterization of the films was accomplished through measures of scanning electronic microscopy and grazing incidence X-rays diffraction analysis. The dosimetric characterization was made of gamma radiation exposure in a 60 Co source, with kerma from 0,1 to 500 Gy. Studies of reproducibility, homogeneity, stability and other environmental effects were also made. LiF and Cu F 2 : LiF; Mg F 2 films were the only ones that presented mechanical stability and reproducibility of the TL emission. There is a strong indication of some correlation between the residual tension fields inside the films and the intensity of its TL emission peaks. LiF monolayer films present supralinear behaviour from 0,2 to 100 Gy. These films present a main TL glow peak around 150 deg C, whose half-time is about 30 days. Its volumetric sensitivity can reach about 60 times that of LiF powder and about 0,25 that of TLD100 (LiF:Mg, Ti commercial dosimeter from Harshaw Chemical Co.) The homogeneity and reproducibility inside a same film batch is better than 12% for 95% confidence level. Cu F 2 : LiF: Mg F 2 films present linear behaviour from 3 to 500 Gy and its main TL glow peak around 200 deg C did not present any fading for a a period of 30 days, in laboratory conditions. This glow peak is characteristic of the Mg doping of LiF, which confirms the diffusion of Mg ions from the Mg F 2 layer to the LiF layer. The TL volumetric sensitivity of these

  8. Dosimetric evaluation of sucrose and granulated cane sugar in the therapeutic dose range.

    Science.gov (United States)

    Davidson, Melanie T M; Jordan, Kevin J

    2009-04-01

    Granulated cane sugar has been used as a dosimetric material to report dose in high dose accidental irradiations. The purpose of this study was to assess whether clinical dosimetry is also plausible with such a commonly available material. The behavior of cane sugar was explored with respect to therapeutically relevant radiation quantities (dose, dose rate) and qualities (energy, radiation type) as well as under different temperature conditions. The stability of the signal postirradiation was also measured. Absorbed dose was measured by spectrophotometric readout of a ferrous ammonium sulfate xylenol orange (FX)-sugar solution in 10 cm path length cells. A visible color change was produced as a function of dose when the irradiated sugar samples were dissolved in FX solution (10% dilution by mass). A comparison of the optical absorbance spectra and dose response of cane sugar with analytical grade sucrose was done to establish a benchmark standard from which subsequent dosimetry measurements can be validated. The response of the sugar dosimeter read at 590 nm was found to be linear over the dose range of 100-2000 cGy, independent of energy (6-18 MV) and of the average dose rate (100-500 cGy/min). The readout of sugar samples irradiated with mixed photon and electron fields was also shown to be independent of radiation type (photons and electrons). Sugar temperature (20-40 degrees C) during irradiation did not affect dose estimates, making it a promising dosimeter for in vivo dosimetry, particularly in cases where the dosimeter must remain in contact with the patient for an extended period of time. Sugar can be used as an integrating dosimeter, since it exhibits no fractionation effects. Granulated cane sugar is cost effective, safe, soft tissue equivalent, and can be used under various experimental conditions, making it a suitable dosimeter for some radiotherapy applications.

  9. 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.

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

    International Nuclear Information System (INIS)

    Ehler, E; Higgins, P; Dusenbery, K

    2014-01-01

    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

  11. CaSO4: Dy + Teflon dosimetric pellets for X, beta and gamma radiation detection

    International Nuclear Information System (INIS)

    Campos, L.L.; Lima, M.F.

    1987-08-01

    CaSO 4 : Dy + TEFLON dosimetric pellets with high sensitivity and low cost for X, beta and gamma radiation monitoring were studied and developed by the Dosimetric Material Production Laboratory of the Radiological Protection Departament and are disposable for sale. The thickness of the pellets are suitable for X, beta and gamma radiation measurements. The dosimetric properties of these pellets were determined and presented in this work. The results show the usefulness of 0,20mm thick pellets for beta radiation monitoring and 0,80mm thick pellets for x and gamma radiation detection. (Author) [pt

  12. SU-D-204-03: Comparison of Patient Positioning Methods Through Modeling of Acute Rectal Toxicity in Intensity Modulated Radiation Therapy for Prostate Cancer. Does Quality of Data Matter More Than the Quantity?

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X; Fatyga, M; Vora, S; Wong, W; Schild, S; Schild, M [Mayo Clinic Arizona, Phoenix, AZ (United States); Herman, M [Mayo Clinic, Rochester, MN (United States); Li, J; Wu, T [Arizona State University, Tempe, AZ (United States)

    2016-06-15

    Purpose: To determine if differences in patient positioning methods have an impact on the incidence and modeling of grade >=2 acute rectal toxicity in prostate cancer patients who were treated with Intensity Modulated Radiation Therapy (IMRT). Methods: We compared two databases of patients treated with radiation therapy for prostate cancer: a database of 79 patients who were treated with 7 field IMRT and daily image guided positioning based on implanted gold markers (IGRTdb), and a database of 302 patients who were treated with 5 field IMRT and daily positioning using a trans-abdominal ultrasound system (USdb). Complete planning dosimetry was available for IGRTdb patients while limited planning dosimetry, recorded at the time of planning, was available for USdb patients. We fit Lyman-Kutcher-Burman (LKB) model to IGRTdb only, and Univariate Logistic Regression (ULR) NTCP model to both databases. We perform Receiver Operating Characteristics analysis to determine the predictive power of NTCP models. Results: The incidence of grade >= 2 acute rectal toxicity in IGRTdb was 20%, while the incidence in USdb was 54%. Fits of both LKB and ULR models yielded predictive NTCP models for IGRTdb patients with Area Under the Curve (AUC) in the 0.63 – 0.67 range. Extrapolation of the ULR model from IGRTdb to planning dosimetry in USdb predicts that the incidence of acute rectal toxicity in USdb should not exceed 40%. Fits of the ULR model to the USdb do not yield predictive NTCP models and their AUC is consistent with AUC = 0.5. Conclusion: Accuracy of a patient positioning system affects clinically observed toxicity rates and the quality of NTCP models that can be derived from toxicity data. Poor correlation between planned and clinically delivered dosimetry may lead to erroneous or poorly performing NTCP models, even if the number of patients in a database is large.

  13. Dosimetric commissioning of a CBCT system for IGRT purposes

    International Nuclear Information System (INIS)

    Alfonso, R.; Ascencion, Y.; Castillo, D.; Linares, H.; Argota, R.; Garcia, F.

    2015-01-01

    During the last few years the use of tomographic imaging systems based on kilo voltage, cone shaped photon beams (kV-CBCT) for ensuring an accurate positioning of patients in radiotherapy treatments has expanded to low income departments, such as those existing in public health systems of low and middle income countries (LMIC). Although several dosimetric studies have been published so far, showing results of collateral dose in patients exposed to kV-CBCT studies for image guidance radiotherapy purposes (IGRT), their main objective is to demonstrate that these doses are significantly lower than the prescribed dose to the target volume and even the dose to organs and healthy tissues. In the actual study a methodology is proposed to reduce the CBCT dose during IGRT procedures for tumor targets located in the thorax region, where motion management is crucial. Criteria for dose optimization, based on image quality indexes and automated positioning accuracy, were implemented. (Author)

  14. Dosimetric aspects of radiolabeled antibodies for tumor therapy

    International Nuclear Information System (INIS)

    Humm, J.L.

    1986-01-01

    Radioimmunotherapy (RIT) is rapidly attracting interest as a potential new weapon in the arsenal for cancer therapy. This article concentrates on some of the dosimetric aspects affecting the potential success of RIT, and examines factors which influence the choice of a radiolabel for RIT. No radionuclide is likely to give an optimum tumor/nontumor insult for all tumor types; therefore, the concept of matching the source to tumor morphology is introduced. Lists of candidate radionuclides are given, classified according to the type of decay, range, and energy of the emission. The article examines how the choice of radionuclide for radiolabeling the antibody affects the local energy deposition in the tumor. Both the effect of tumor size on the energy absorbed fraction and the problem of antibody binding heterogeneity are discussed. The approach to RIT is to relate the choice of radionuclide to the physical properties of the tumor. 26 references

  15. Dosimetric analysis of radiation sources to use in dermatological lesions

    International Nuclear Information System (INIS)

    Tada, Ariane

    2010-01-01

    Skin lesions undergoing therapy with radiation sources may have different patterns of malignancy. Malignant lesions or cancer most commonly found in radiotherapy services are carcinomas. Radiation therapy in skin lesions is performed with low penetration beams and orthovoltage X-rays, electron beams and radioactive sources ( 192 Ir, 198 Au, e 90 Sr) arranged on a surface mold or in metal applicator. This study aims to analyze the therapeutic radiation dose profile produced by radiation sources used in skin lesions radiotherapy procedures. Experimental measurements for the analysis of dosimetric radiation sources were compared with calculations obtained from a computer system based on the Monte Carlo Method. Computational results had a good agreement with the experimental measurements. Experimental measurements and computational results by the MCNP4C code have been used to validate the calculations obtained by MCNP code and to provide a reliable medical application for each clinical case. (author)

  16. Dosimetric properties of the fast neutron therapy beams at TAMVEC

    International Nuclear Information System (INIS)

    Almond, P.R.; Smith, A.R.; Smathers, J.R.; Otte, V.A.

    1975-01-01

    In October 1972, M.D. Anderson Hospital and Tumor Institute of the University of Texas System Cancer Center initiated a clinical trial of fast neutron radiotherapy using the cyclotron at Texas A and M University. Initially, the study used neutrons produced by bombarding beryllium with 16 MeV deuterons, but since March, 1973, neutrons from 50 MeV deuterons have been used. The dosimetric properties of the 30 MeV beams have also been measured for comparison with the neutron beams from D-T generators. The three beams are compared in terms of dose rate, skin sparing, depth dose and field flatness. Isodose curves for treatment planning were generated using the decrement line method and compared to curves measured by a computer controlled isodose plotter. This system was also used to measure the isodose curves for wedge fields. Dosimetry checks on various patients were made using silicon diodes as in vivo fast neutron dosimeters

  17. A dosimetric study during cardiac angiography in young children

    International Nuclear Information System (INIS)

    Amiel, M.; Clermont, A.; Jocteur-Monrozier, D.; Moroni, J.P.; Brun, P.

    1976-01-01

    A dosimetric study was carried out in collaboration with the SCPRI in 30 infants during cardiac catheterization for a congenital cardiopathy. As far as the doctor is concerned, the results show that the dose received by the right hand of the operator is the only one that is relatively high and notably higher than in the adult; the other results are in agreement with those published in the literature. For the manipulator the doses received are practically negligible. This finding does not agree with those of certain publications in the literature and it emphasizes the importance of the working conditions for these personnel. For infants, the gonadal dose is much higher than in the adult and the magnitude of the dose relative to the dose at the place of entry of the incident beam, taking into account the weight of the infant, certaintly represents a long-term risk, in particular, in patients who must undergo repeated examinations [fr

  18. Dosimetric comparison between techniques for irradiation of breast plastron

    International Nuclear Information System (INIS)

    Trinca, W.C.; Bruning, F.F.; Caldeira, F A.M.; Silveira, T.B da; Batista, D.V.S.; Andrade, R.R.

    2009-01-01

    Patients with breast cancer undergoing radical mastectomy has as an indication of adjuvancy the irradiation of the breast plastron. This paper makes a comparison between different techniques for treatment of breast plastron routinely used in the National Cancer Institute of Brazil (INCA): The irradiation with tangential fields of photons at 6 MV linear accelerator and irradiation with direct angled fields of electron beams of 6 and 9 MeV. We performed dosimetric comparisons in a tissue-equivalent phantom with the use of radiochromic films for verification of coverage and homogeneity of dose for all technical requirements. Tangential fields in the coverage and homogeneity were satisfactory and well cover the clinical aspects as well as beam 9 MeV, despite a small loss at the edge of the external field. Already in 6 MeV beam, there was significant loss in the end, with significant subdoses of 3 cm in the last field. (author)

  19. Radiation hazards in uranium mining. Epidemiological and dosimetric approaches

    International Nuclear Information System (INIS)

    Myers, D.K.; Johnson, J.R.

    1989-01-01

    Potential health hazards resulting from exposure to various sources of radiation associated with uranium mining have been reviewed: 1) epidemiological observations on groups of miners exposed in the past to high concentrations of radon progeny have been interpreted to suggest a lifetime risk of about 3 x 10 -4 lung cancers per WLM; 2) the total risk of serious health effects resulting from exposure of workers to whole body gamma-radiation might be taken to be about 2 x 10 -2 per Sv; and 3) the potential health effects of inhalation of thoron progeny or of radioactive ore dusts can only be estimated from dosimetric calculations. A review of the uncertainties involved in these calculations suggests that ICRP estimates of the potential toxicity of inhaled thoron progeny are as good as those for inhaled radon progeny. However, the potential health hazards from inhaled uranium and thorium ore dusts have probably been overestimated by a factor of 2 to 10-fold

  20. Beam standardization and dosimetric methodology in computed tomography

    International Nuclear Information System (INIS)

    Maia, Ana Figueiredo

    2005-01-01

    Special ionization chambers, named pencil ionization chambers, are used in dosimetric procedures in computed tomography beams (CT). In this work, an extensive study about pencil ionization chambers was performed, as a contribution to the accuracy of the dosimetric procedures in CT beams. The international scientific community has recently been discussing the need of the establishment of a specific calibration procedure for CT ionization chambers, once these chambers present special characteristics that differentiate them from other ionization chambers used in diagnostic radiology beams. In this work, an adequate calibration procedure for pencil ionization chambers was established at the Calibration Laboratory, of the Institute de Pesquisas Energeticas e Nucleares, in accordance with the most recent international recommendations. Two calibration methodologies were tested and analyzed by comparative studies. Moreover, a new extended length parallel plate ionization chamber, with a transversal section very similar to pencil ionization chambers, was developed. The operational characteristics of this chamber were determined and the results obtained showed that its behaviour is adequate as a reference system in CT standard beams. Two other studies were performed during this work, both using CT ionization chambers. The first study was about the performance of a pencil ionization chamber in standard radiation beams of several types and energies, and the results showed that this chamber presents satisfactory behaviour in other radiation qualities as of diagnostic radiology, mammography and radiotherapy. In the second study, a tandem system for verification of hal'-value layer variations in CT equipment, using a pencil ionization chamber, was developed. Because of the X rays tube rotation, the determination of half-value layers in computed tomography equipment is not an easy task, and it is usually not performed within quality control programs. (author)

  1. Representing the dosimetric impact of deformable image registration errors

    Science.gov (United States)

    Vickress, Jason; Battista, Jerry; Barnett, Rob; Yartsev, Slav

    2017-09-01

    Deformable image registration (DIR) is emerging as a tool in radiation therapy for calculating the cumulative dose distribution across multiple fractions of treatment. Unfortunately, due to the variable nature of DIR algorithms and dependence of performance on image quality, registration errors can result in dose accumulation errors. In this study, landmarked images were used to characterize the DIR error throughout an image space and determine its impact on dosimetric analysis. Ten thoracic 4DCT images with 300 landmarks per image study matching the end-inspiration and end-expiration phases were obtained from ‘dir-labs’. DIR was performed using commercial software MIM Maestro. The range of dose uncertainty (RDU) was calculated at each landmark pair as the maximum and minimum of the doses within a sphere around the landmark in the end-expiration phase. The radius of the sphere was defined by a measure of DIR error which included either the actual DIR error, mean DIR error per study, constant errors of 2 or 5 mm, inverse consistency error, transitivity error or the distance discordance metric (DDM). The RDUs were evaluated using the magnitude of dose uncertainty (MDU) and inclusion rate (IR) of actual error lying within the predicted RDU. The RDU was calculated for 300 landmark pairs on each 4DCT study for all measures of DIR error. The most representative RDU was determined using the actual DIR error with a MDU of 2.5 Gy and IR of 97%. Across all other measures of DIR error, the DDM was most predictive with a MDU of 2.5 Gy and IR of 86%, closest to the actual DIR error. The proposed method represents the range of dosimetric uncertainty of DIR error using either landmarks at specific voxels or measures of registration accuracy throughout the volume.

  2. EPR dosimetric properties of nano-barium sulfate

    International Nuclear Information System (INIS)

    Aboelezz, E.; Hassan, G.M.; Sharaf, M.A.; El-Khodary, A.

    2015-01-01

    Nano/micro BaSO 4 were prepared through the co-precipitation method to measure ionizing radiation doses using electron paramagnetic resonance (EPR). The nano-BaSO 4 sample was characterized using X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The dose response and fading properties of nano- and micro-phase BaSO 4 were compared in EPR spectra. The prepared nano- and micro-BaSO 4 samples have the same hole and electron centers, which may be attributed to SO 4 − and SO 3 − , respectively. The dosimetric signals for prepared nano- and micro-BaSO 4 have spectroscopic splitting factor (g) with values 2.0025±0.0006 and 2.0027±0.0006, respectively. The nanocrystalline sample has a linear γ-ray dose response over the range 0.4 Gy–1 kGy. The performance parameters which including detection limit and critical level calculated from weighted and unweighted least-squares fitting. The sensitivity of nano-BaSO 4 to γ-ray is one and a half times more than alanine. The lifetime and activation energy for nano-BaSO 4 were estimated by conducting a thermal stability study, and were 5.7±1.1×10 4 years and 0.73±0.14 eV, respectively. The combined and expanded uncertainties accompanying measurements were ±3.89% and ±7.78%, respectively. - Highlights: • Preparation of nano-BaSO 4 using the co-precipitation method. • Study of the dosimetric properties of nano-barium sulfate using the EPR technique. • Comparison between a new EPR dosimeter using nano-materials and standard alanine. • Calculation of the uncertainty budget for nano-BaSO 4

  3. Dosimetric characterization of radionuclides for systemic tumor therapy: Influence of particle range, photon emission, and subcellular distribution

    International Nuclear Information System (INIS)

    Uusijaervi, Helena; Bernhardt, Peter; Ericsson, Thomas; Forssell-Aronsson, Eva

    2006-01-01

    Various radionuclides have been proposed for systemic tumor therapy. However, in most dosimetric analysis of proposed radionuclides the charged particles are taken into consideration while the potential photons are ignored. The photons will cause undesirable irradiation of normal tissue, and increase the probability of toxicity in, e.g., the bone marrow. The aim of this study was to investigate the dosimetric properties according to particle range, photon emission, and subcellular radionuclide distribution, of a selection of radionuclides used or proposed for radionuclide therapy, and to investigate the possibility of dividing radionuclides into groups according to their dosimetric properties. The absorbed dose rate to the tumors divided by the absorbed dose rate to the normal tissue (TND) was estimated for different tumor sizes in a mathematical model of the human body. The body was simulated as a 70-kg ellipsoid and the tumors as spheres of different sizes (1 ng-100 g). The radionuclides were either assumed to be uniformly distributed throughout the entire tumor and normal tissue, or located in the nucleus or the cytoplasm of the tumor cells and on the cell membrane of the normal cells. Fifty-nine radionuclides were studied together with monoenergetic electrons, positrons, and alpha particles. The tumor and normal tissue were assumed to be of water density. The activity concentration ratio between the tumor and normal tissue was assumed to be 25. The radionuclides emitting low-energy electrons combined with a low photon contribution, and the alpha emitters showed high TND values for most tumor sizes. Electrons with higher energy gave reduced TND values for small tumors, while a higher photon contribution reduced the TND values for large tumors. Radionuclides with high photon contributions showed low TND value for all tumor sizes studied. The radionuclides studied could be divided into four main groups according to their TND values: beta emitters, Auger electron

  4. 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.

  5. 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.''

  6. 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.

  7. QUANTITY DISCOUNTS IN SUPPLIER SELECTION PROBLEM BY USE OF FUZZY MULTI-CRITERIA PROGRAMMING

    Directory of Open Access Journals (Sweden)

    Tunjo Perić

    2011-02-01

    Full Text Available Supplier selection in supply chain is a multi-criteria problem that involves a number of quantitative and qualitative factors. This paper deals with a concrete problem of flour purchase by a company that manufactures bakery products and the purchasing price of flour depends on the quantity ordered. The criteria for supplier selection and quantities supplied by individual suppliers are: purchase costs, product quality and reliability of suppliers. The problem is solved using a model that combines revised weighting method and fuzzy multi-criteria linear programming (FMCLP. The paper highlights the efficiency of the proposed methodology in conditions when purchasing prices depend on order quantities.

  8. IPIP: A new approach to inverse planning for HDR brachytherapy by directly optimizing dosimetric indices

    OpenAIRE

    Pouliot, Jean; Cunha, Jason Adam; Hsu, I-Chow

    2011-01-01

    Purpose: Many planning methods for high dose rate (HDR) brachytherapy require an iterative approach. A set of computational parameters are hypothesized that will g ive a dose plan that meets dosimetric criteria. A dose plan is computed using these parameter

  9. Six categories of ionizing radiation quantities practical in various fields

    International Nuclear Information System (INIS)

    Zheng Junzheng; Zhuo Weihai

    2011-01-01

    This paper is the part of review on the evolvement of the systems for ionizing radiation quantities and units. In the paper, for better understanding and correct use of the relevant quantities of ionizing radiation, the major ionizing radiation quantities in various fields are divided into six categories. (authors)

  10. Relationships of chemical composition, quantity of milt to fertility and ...

    African Journals Online (AJOL)

    The biochemical composition of milt and the effect of its varying quantity on fertility and hatchability of Clarias gariepinus (African catfish) eggs were investigated. The study aimed at determining the right quantity of milt that can be used to fertilize certain quantity of eggs. The study further examined the effect of varying ...

  11. 41 CFR 101-27.102 - Economic order quantity principle.

    Science.gov (United States)

    2010-07-01

    ... MANAGEMENT 27.1-Stock Replenishment § 101-27.102 Economic order quantity principle. The economic order quantity (EOQ) principle is a means for achieving economical inventory management. Application of the EOQ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Economic order quantity...

  12. Dosimetric study for characterization of a postal system of quality control in brachytherapy

    International Nuclear Information System (INIS)

    Alves, Victor Gabriel Leandro; Queiroz Filho, Pedro Pacheco de; Santos, Denison de Souza; Begalli, Marcia

    2009-01-01

    This work presents a dosimetric study of a postal system, to be developed for measurements of brachytherapy. It was projected a PMMA phantom with orifices for insertion of the high dose 192 Ir source and the T L dosemeters. The system was characterized with using of Monte Carlo simulations, using the dosimetric magnitudes defined at the T G-43 of AAPM, as function of radial dose g(f)

  13. Dosimetric control: report of French submarine forces from 1989 to 1999

    International Nuclear Information System (INIS)

    Laroche, P.; Rousset, J.; Amabile, J.C.; Roe, H.

    2001-01-01

    We report on the Ile Longue strategic site and describe the medical and dosimetric monitoring of nuclear submarine crews. Over the past eleven years, dosimetric results of nuclear submarine crews have been gathered. We have compared these results to those of workers employed by outside enterprises and the directorate of naval constructions. During this period, neither the crew members nor the workers have been over-exposed. Considering each group, we show a more or less distinct diminution of equivalent doses. (authors)

  14. IPIP: A New Approach to Inverse Planning for HDR Brachytherapy by Directly Optimizing Dosimetric Indices

    OpenAIRE

    Siauw, Timmy; Cunha, Adam; Atamturk, Alper; Hsu, I-Chow; Pouliot, Jean; Goldberg, Ken

    2010-01-01

    Purpose: Many planning methods for high dose rate (HDR) brachytherapy treatment planning require an iterative approach. A set of computational parameters are hypothesized that will give a dose plan that meets dosimetric criteria. A dose plan is computed using these parameters, and if any dosimetric criteria are not met, the process is iterated until a suitable dose plan is found. In this way, the dose distribution is controlled by abstract parameters. The purpose of this study is to improve H...

  15. Dosimetric impact of geometric errors due to respiratory motion prediction on dynamic multileaf collimator-based four-dimensional radiation delivery

    International Nuclear Information System (INIS)

    Vedam, S.; Docef, A.; Fix, M.; Murphy, M.; Keall, P.

    2005-01-01

    The synchronization of dynamic multileaf collimator (DMLC) response with respiratory motion is critical to ensure the accuracy of DMLC-based four dimensional (4D) radiation delivery. In practice, however, a finite time delay (response time) between the acquisition of tumor position and multileaf collimator response necessitates predictive models of respiratory tumor motion to synchronize radiation delivery. Predicting a complex process such as respiratory motion introduces geometric errors, which have been reported in several publications. However, the dosimetric effect of such errors on 4D radiation delivery has not yet been investigated. Thus, our aim in this work was to quantify the dosimetric effects of geometric error due to prediction under several different conditions. Conformal and intensity modulated radiation therapy (IMRT) plans for a lung patient were generated for anterior-posterior/posterior-anterior (AP/PA) beam arrangements at 6 and 18 MV energies to provide planned dose distributions. Respiratory motion data was obtained from 60 diaphragm-motion fluoroscopy recordings from five patients. A linear adaptive filter was employed to predict the tumor position. The geometric error of prediction was defined as the absolute difference between predicted and actual positions at each diaphragm position. Distributions of geometric error of prediction were obtained for all of the respiratory motion data. Planned dose distributions were then convolved with distributions for the geometric error of prediction to obtain convolved dose distributions. The dosimetric effect of such geometric errors was determined as a function of several variables: response time (0-0.6 s), beam energy (6/18 MV), treatment delivery (3D/4D), treatment type (conformal/IMRT), beam direction (AP/PA), and breathing training type (free breathing/audio instruction/visual feedback). Dose difference and distance-to-agreement analysis was employed to quantify results. Based on our data, the

  16. The Quantity Theory of Money and Its Long Run Implications: Empirical Evidence from Nigeria

    OpenAIRE

    Alimi, R. Santos

    2012-01-01

    The Quantity Theory of Money (QTM) is one of the popular classical macroeconomic models that explain the relationship between the quantity of money in an economy and the level of prices of goods and services. This study investigates this relationship for Nigeria economy over the period of 1960 to 2009. To check the stationarity properties, we employed Augmented Dickey Fuller (ADF) and Phillips-Perron (PP) test and found all the concerned variables are stationary only in the first differenced ...

  17. Gas-conditioning and fuelling installation for low-quantity biogas production - Phase II: construction and operation of a functional model; Aufbereitungs- und Betankungsanlage fuer kleinere Biogasproduktionsmengen. Phase II: Bau und Betrieb eines Funktionsmusters - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Oester, U.

    2009-12-15

    This final report for the Swiss Federal Office of Energy (SFOE) describes and discusses the construction and operation of a functional model for gas-conditioning and fuelling for biogas produced in small installations with methane content of around 55%. In normal natural gas mains the methane content is quoted at 80% to 90%. Large biogas treatment installations are designed for 100 m{sup 3}/h and are regarded by the author as being too expensive for small installations. The development and functioning of a functional model for the removal of carbon dioxide is described and the results obtained are presented and discussed. Work still to be done to increase the amount of CO{sub 2} extracted is discussed. Also economic feasibility and information topics are discussed.

  18. The covariance matrix of derived quantities and their combination

    International Nuclear Information System (INIS)

    Zhao, Z.; Perey, F.G.

    1992-06-01

    The covariance matrix of quantities derived from measured data via nonlinear relations are only approximate since they are functions of the measured data taken as estimates for the true values of the measured quantities. The evaluation of such derived quantities entails new estimates for the true values of the measured quantities and consequently implies a modification of the covariance matrix of the derived quantities that was used in the evaluation process. Failure to recognize such an implication can lead to inconsistencies between the results of different evaluation strategies. In this report we show that an iterative procedure can eliminate such inconsistencies

  19. Experience in the performance of a system of dosimetric design of radiotherapy and prospects of its development

    International Nuclear Information System (INIS)

    Tsyb, A.F.; Mardynskij, Yu.S.; Chilingarov, K.M.

    1987-01-01

    A model of a system of dosimetric design of radiotherapy on the basis of SM-4 and ES-1033 computers has been developed and is being tested. Radiotherapy for over 600 patients with tumors of different sites was designed within 1 year. The simplicity of the system allowed a radiologist to take an active part in the choice of a favourable radiotherapy design. Four variants of dose distributions on an average were computed for each patient. A study of the time characteristics of the system has shown that the time of input of the data on a patient and beam parameters does not practically depend on the computer speed and lasts for an average of 15 min. Dose field computation and optimization of inputs vary from 0.4 to 6 min depending on a volume of computation and computer type. A one-task computer system with one working place and memory is able to meet the requirements in dosimetric design for 2-3 radiotherapeutic units. More units will require multitask and all-purpose computers with 2 and more working places. Minimum standards of computer memory and speed are the same as in the first case

  20. 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

  1. 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.

  2. Market making, prices, and quantity limits

    NARCIS (Netherlands)

    Dupont, D.Y.

    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

  3. 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.

  4. 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)

  5. Simulation and dosimetric analysis of proton and carbon ion therapy in the treatment of uveal melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Christovao, Marilia Tavares, E-mail: marilia@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Campos, Tarcisio Passos Ribeiro de; Trindade, Bruno Machado [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

    2011-11-15

    The present paper addresses the dosimetric evaluation of carbon ion radiotherapy as compared with proton therapy. Materials and methods: computer simulations were undertaken with the Geant4 (GEometry ANd Tracking) code. An eye model discretized into voxels and implemented in the Siscodes system (computer system for dosimetry in radiation therapy) was utilized to generate and superimpose depth dose profiles and isodose curves. Different values for beam energy were adopted in the simulations of carbon ion beams, while in the simulation with proton beams irradiation line devices were included with different absorbing material thicknesses. Results: the simulations outputs were processed and integrated into the Siscodes to generate the spatial dose distribution in the eye model, considering changes in the beam entrance position. The dose rates were normalized as a function of the maximum dose for a beam at a specific entrance position, incident particle energy and number of incident carbon ions and protons. Conclusion: the described benefits together with the presented results contribute to the development of clinical applications and researches on carbon ion and proton therapy. (author)

  6. Optimizing basin-scale coupled water quantity and water quality management with stochastic dynamic programming

    DEFF Research Database (Denmark)

    Davidsen, Claus; Liu, Suxia; Mo, Xingguo

    2015-01-01

    Few studies address water quality in hydro-economic models, which often focus primarily on optimal allocation of water quantities. Water quality and water quantity are closely coupled, and optimal management with focus solely on either quantity or quality may cause large costs in terms of the oth......-er component. In this study, we couple water quality and water quantity in a joint hydro-economic catchment-scale optimization problem. Stochastic dynamic programming (SDP) is used to minimize the basin-wide total costs arising from water allocation, water curtailment and water treatment. The simple water...... concentrations. Inelastic water demands, fixed water allocation curtailment costs and fixed wastewater treatment costs (before and after use) are estimated for the water users (agriculture, industry and domestic). If the BOD concentration exceeds a given user pollution thresh-old, the user will need to pay...

  7. 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.

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

    International Nuclear Information System (INIS)

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

    2004-01-01

    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

  9. 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 benchmark...... 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....

  10. Dosimetric implications of age related glandular changes in screening mammography

    International Nuclear Information System (INIS)

    Beckett, J.R.; Kotre, C.J.

    2000-01-01

    The UK National Health Service Breast Screening Programme is currently organized to routinely screen women between the ages of 50 and 64, with screening for older women available on request. The lower end of this age range closely matches the median age for the menopause (51 years), during which significant changes in the composition of the breast are known to occur. In order to quantify the dosimetric effect of these changes, radiographic factors and compressed breast thickness data for a cohort of 1258 women aged between 35 and 79 undergoing breast screening mammography have been used to derive estimates of breast glandularity and mean glandular dose (MGD), and examine their variation with age. The variation of mean radiographic exposure factors with age is also investigated. The presence of a significant number of age trial women within the cohort allowed an extended age range to be studied. Estimates of MGD including corrections for breast glandularity based on compressed breast thickness only, compressed breast thickness and age and for each individual woman are compared with the MGD based on the conventional assumption of a 50:50 adipose/glandular composition. It has been found that the use of the conventional 50:50 assumption leads to overestimates of MGD of up to 13% over the age range considered. By using compressed breast thickness to estimate breast glandularity, this error range can be reduced to 8%, whilst age and compressed breast thickness based glandularity estimates result in an error range of 1%. (author)

  11. Dosimetric properties of commercial glasses and sand for high doses

    International Nuclear Information System (INIS)

    Teixeira, Maria Ines

    2004-01-01

    Commercial glasses (transparent and colored) produced by Cebrace, Brazil, Sao Paulo, and sand samples of different Brazilian beaches were studied, due to their low cost and easy handling, to verify the possibility of their use in high dose dosimetry. The main dosimetric characteristics were determined using a densitometer, a spectrophotometer, a thermoluminescent (TL) reader and an electronic paramagnetic resonance system. The gamma irradiations were carried out using a Gamma-Cell 220 and a panoramic source ( 60 Co) of IPEN. An optical absorption band was observed at 420 nm in the glass samples. The TL glow curves presented peaks at 205 deg C, 135 deg C, 150 deg C and 145 deg C for the transparent, bronze, brown and green glass samples, respectively. All EPR spectra of the glasses showed Fe 3+ characteristic signals at g = 4.27 and 2.01. The gamma irradiated sand samples presented two peaks at 110 deg C and 170 deg C and an EPR signal at g= 1.999. However, these materials present a pronounced thermal fading at room temperature after irradiation. With the objective to minimize this thermal fading, both glass and sand samples were submitted to different pre- and post-irradiation thermal treatments. The glass and sand samples showed the possibility of utilization for high dose dosimetry and as Yes/No irradiation detectors. (author)

  12. Dosimetric analysis of radiation sources for use dermatological lesions

    International Nuclear Information System (INIS)

    Tada, Ariane

    2010-01-01

    Skin lesions undergoing therapy with radiation sources may have different patterns of malignancy. Malignant lesions or cancer most commonly found in radiotherapy services are carcinomas. Radiation therapy in skin lesions is performed with low penetration beams and orthovoltage X-rays, electron beams and radioactive sources ( 192 Ir, 198 Au, e 90 Sr) arranged on a surface mold or in metal applicator. This study aims to analyze the therapeutic radiation dose profile produced by radiation sources used in skin lesions radiotherapy procedures . Experimental measurements for the analysis of dosimetric radiation sources were compared with calculations obtained from a computer system based on the Monte Carlo Method. Computational results had a good agreement with the experimental measurements. Experimental measurements and computational results by the MCNP4C code were both physically consistent as expected. These experimental measurements compared with calculations using the MCNP-4C code have been used to validate the calculations obtained by MCNP code and to provide a reliable medical application for each clinical case. (author)

  13. Investigation of PBAT dosimetric properties for high gamma dose dosimetry

    International Nuclear Information System (INIS)

    Cunha, Elisete L.; Schimitberger, Thiago

    2017-01-01

    Poly(butylene adipate-co-terephthalate) (PBAT) is an aliphatic-aromatic copolyester which is biodegradable. It is a non-photoluminescent copolyester that becomes photoluminescent after previous exposure to gamma doses higher than 100 kGy. After the previous high energy irradiation, the material shows the highest photo-stimulated luminescence emission when excited with a LED source at wavelengths ranging from 370 to 405 nm. In this work we investigated the enhancement of the photoluminescence (PL) and dosimetric properties of PBAT, after exposure to high doses of gamma radiation ranging from 50 to 4,000 kGy. In this investigation we demonstrate that increasing the PBAT film thickness by 100 μm enhances the PL output by 3.5 times, when irradiated with 500 kGy. Also, besides the already known color green brightness, the PL intensity can also be used for high dose dosimetry purposes for doses ranging from 50 to 750 kGy. The FTIR analysis has demonstrated that the there is a linear relationship between peak intensity and dose for doses ranging from 100 and 2,000 kGy for the absorbance peaks at 3,241 cm -1 and 3271 cm -1 , with linear correlation coefficients of 0.9981 and 0.9992, respectively. The results indicate that PBAT has great potential for applications in bio-imaging devices and high gamma dose dosimetry. (author)

  14. Investigation of PBAT dosimetric properties for high gamma dose dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Elisete L.; Schimitberger, Thiago, E-mail: elisete.cunha@cdtn.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Oliveira, Cristiana M.; Faria, Luiz O., E-mail: farialo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    Poly(butylene adipate-co-terephthalate) (PBAT) is an aliphatic-aromatic copolyester which is biodegradable. It is a non-photoluminescent copolyester that becomes photoluminescent after previous exposure to gamma doses higher than 100 kGy. After the previous high energy irradiation, the material shows the highest photo-stimulated luminescence emission when excited with a LED source at wavelengths ranging from 370 to 405 nm. In this work we investigated the enhancement of the photoluminescence (PL) and dosimetric properties of PBAT, after exposure to high doses of gamma radiation ranging from 50 to 4,000 kGy. In this investigation we demonstrate that increasing the PBAT film thickness by 100 μm enhances the PL output by 3.5 times, when irradiated with 500 kGy. Also, besides the already known color green brightness, the PL intensity can also be used for high dose dosimetry purposes for doses ranging from 50 to 750 kGy. The FTIR analysis has demonstrated that the there is a linear relationship between peak intensity and dose for doses ranging from 100 and 2,000 kGy for the absorbance peaks at 3,241 cm{sup -1} and 3271 cm{sup -1}, with linear correlation coefficients of 0.9981 and 0.9992, respectively. The results indicate that PBAT has great potential for applications in bio-imaging devices and high gamma dose dosimetry. (author)

  15. Dosimetric predictors of diarrhea during radiotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Sanguineti, Giuseppe; Endres, Eugene J.; Parker, Brent C.; Sormani, Maria Pia

    2009-01-01

    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 15 and IC-V 30 , but not IC-V 45 , were correlated to the endpoint; at multivariate analysis, only IC-V 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.)

  16. Dosimetric Uncertainties in Verification of Intensity Modulated Photon Beams

    International Nuclear Information System (INIS)

    Jurkovic, S.

    2010-01-01

    The doctoral thesis presents method for the calculation of the compensators' shape to modulate linear accelerators' beams. Characteristic of the method is more strict calculation of the scattered radiation in beams with an inhomogeneous cross-section than it was before. Method could be applied in various clinical situations. It's dosimetric verification was made in phantoms, measuring dose distributions using ionization chambers as well as radiographic film. Therefore, ionization chambers were used for the evaluation of modulator shape and film was used for the evaluation of two-dimensional dose distributions. It is well known that dosimetry of the intensity modulated photon beams is rather complicated regarding inhomogeneity of the dose distribution. The main reason for that is the beam modulator which changes spectral distribution of the beam. Possibility of use different types of detectors for the measurements of dose distributions in modulated photon beams and their accuracy were examined. Small volume ionization chambers, different diodes and amorphus silicon detector and radigraphic film were used. Measured dose distributions were compared between each other as well as with distributions simulated using Monte Carlo particle transport algorithm. In this way the most accurate method for the verification of modulate photon beams is suggested. (author)

  17. Physical quantities, their role and treatment in gasflow measurement techniques

    International Nuclear Information System (INIS)

    Narjes, L.

    1977-06-01

    We begin by taking a closer look at the concepts physical quantity, dimension and unit of measurement. Then a survey is given of the physical quantities applied in gasflow measurement techniques. Here the volume-, as well as the mass-flow rate, as derived quantities are of particular interest. The application of these quantities in relation to the legal units of measurement is specifically described. In addition the quantity equation and further the quantity equation adapted to the use of suitable units and their modes of application are compared. In the appendix four examples clarify these modes. Special attention is paid to the quantity equation adapted to practically oriented units. The applications of this type of equation in VDI regulations, standards and other technical guidelines for measurement of flow are mentioned. Moreover, the meaning of the standard state for the comparison of flows of gaseous fluids is illustrated. The difficulties concerning an international agreement on uniform standard temperature are explained. Starting from there, the advantages of the fundamental quantity 'amount of substance' applied to the measurement of flow are described. The use of this quantity for the thermodynamic state of ideal and real gases, respectively gas mixtures, is demonstrated in the appendix by an example. (orig.) [de

  18. Comparative dosimetric study in the estimation of the dose rate of the Transelektro LGI-01 irradiator

    International Nuclear Information System (INIS)

    Carrasco A, H.; Urena N, F.F.

    2004-01-01

    The 60 Co TRANSELEKTRO, model LGI-0 1, Hungarian, is similar to the Canadian Gamma cell. The evaluation of the dose ratio in the geometric center of the exposition chamber of the LGI-0 1 is presented in this paper. In order to do this two types of dosimeters were used: the alanine, and the L8-C 1 red acrylic (Canadian). Three dosimeters of each type were irradiated at 1, 2, 3, 4, 5, 6, 7 and 8 h. The respective intensities and absorbencies were measured and used to determine the proper absorbed doses and the dose ratio. The results obtained with both dosimeters were compared with the ratio dose that was reported by the Secondary Laboratory of Dosimetric Calibration of the Metrology Department of the ININ, which used a ionization chamber for the calibration of the LGI-0 1. The alanine dosemeter showed a ± 1.3% dispersion while with the acrylic dosemeter the dispersion was of ± 3.2%, with respect to the value reported by the authorized Calibration Laboratory. This paper was also used to update the calibration table of the L8-C1 red acrylic. (Author)

  19. Dosimetric evaluation of a Monte Carlo IMRT treatment planning system incorporating the MIMiC

    International Nuclear Information System (INIS)

    Rassiah-Szegedi, P; Fuss, M; Sheikh-Bagheri, D; Szegedi, M; Stathakis, S; Lancaster, J; Papanikolaou, N; Salter, B

    2007-01-01

    The high dose per fraction delivered to lung lesions in stereotactic body radiation therapy (SBRT) demands high dose calculation and delivery accuracy. The inhomogeneous density in the thoracic region along with the small fields used typically in intensity-modulated radiation therapy (IMRT) treatments poses a challenge in the accuracy of dose calculation. In this study we dosimetrically evaluated a pre-release version of a Monte Carlo planning system (PEREGRINE 1.6b, NOMOS Corp., Cranberry Township, PA), which incorporates the modeling of serial tomotherapy IMRT treatments with the binary multileaf intensity modulating collimator (MIMiC). The aim of this study is to show the validation process of PEREGRINE 1.6b since it was used as a benchmark to investigate the accuracy of doses calculated by a finite size pencil beam (FSPB) algorithm for lung lesions treated on the SBRT dose regime via serial tomotherapy in our previous study. Doses calculated by PEREGRINE were compared against measurements in homogeneous and inhomogeneous materials carried out on a Varian 600C with a 6 MV photon beam. Phantom studies simulating various sized lesions were also carried out to explain some of the large dose discrepancies seen in the dose calculations with small lesions. Doses calculated by PEREGRINE agreed to within 2% in water and up to 3% for measurements in an inhomogeneous phantom containing lung, bone and unit density tissue

  20. 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)

  1. Organ motion study and dosimetric impact of respiratory gating radiotherapy for esophageal cancer

    International Nuclear Information System (INIS)

    Lorchel, F.

    2007-04-01

    Chemoradiotherapy is now the standard treatment for locally advanced or inoperable esophageal carcinoma. In this indication, conformal radiotherapy is generally used. However, prognosis remains poor for these patients. Respiratory gating radiotherapy can decrease healthy tissues irradiation and allows escalation dose in lung, liver and breast cancer. In order to improve radiotherapy technique, we propose to study the feasibility of respiratory gating for esophageal cancer. We will study the respiratory motions of esophageal cancer to optimize target volume delineation, especially the internal margin (I.M.). We will test the correlation between tumour and chest wall displacements to prove that esophageal cancer motions are induced by respiration. This is essential before using free breathing respiratory gating systems. We will work out the dosimetric impact of respiratory gating using various dosimetric analysis parameters. We will compare dosimetric plans at end expiration, end inspiration and deep inspiration with dosimetric plan in free-breathing condition. This will allow us to establish the best respiratory phase to irradiate for each gating system. This dosimetric study will be completed with linear quadratic equivalent uniform dose (E.U.D.) calculation for each volume of interest. Previously, we will do a theoretical study of histogram dose volume gradation to point up its use. (author)

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

    International Nuclear Information System (INIS)

    Moura, Eduardo S.; Mosca, Rodrigo C.; Zeituni, Carlos A.; Rostelato, Maria Elisa C.M.; Mathor, Monica B.; Sakuraba, Roberto K.; Goncalves, Vinicius D.

    2011-01-01

    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)

  3. Study of dosimetric systems-ferrous sulfate-ferric sulfate, glass slides and dyed aqueous solutions

    International Nuclear Information System (INIS)

    Fernandes, L.

    1979-01-01

    The effect of some variables which can effect the preparation of the ferrous sulfate used as dosimetric solution has been studied. Among these variables the purity of the water used for the preparation of the solution and the presence (or absence) of oxygen in the dosimetric solution were considered. The dose rate distribution according to the transverse and longitudinal sections of the Co 60 irradiator was studied experimentally, using the dosimetric solution, and theoretically, using a computer program (KIFE). The results obtained with the ferrous sulface dosimetric solution were used as reference for the study of the application of EM and MSG glass slide as a dosimetric system. For this purpose the effects of the weakening of the coloration induced in the glass by gamma rays (Co 60 ) and the relationship between the absorbed dose of radiation and the ratio between the variation in absorbation value and the thickness of the glass irradiated, were studied. A study was also made of the use of the dye indicators bromothymol-blue, methyl-orange, Congo-red, neutral-red and p-nitrophenol, in aqueous solution, for radiation dose measurements. The bleaching of each indicator solution, under gamma-radiation (Co 60 ) was studied in oxygen and nitrogen atmospheres.(Author) [pt

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

    International Nuclear Information System (INIS)

    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.

    2004-01-01

    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

  5. 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)

  6. 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 quality service. Consultant QSs experienced in the use 5D BIM, from the New Zealand office of one 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 visualization that BIM provides, along with the rapid identification of design changes. However, realization of these perceived benefits 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. However, participants perceived that 5D BIM implementation will achieve these benefits 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

  7. Dosimetric aspects of radiation processing of food and allied products

    International Nuclear Information System (INIS)

    Sharma, G.; Bhat, R.M.; Bhatt, B.C.

    2010-01-01

    Full text: Gamma radiation processing in the last 4-5 decades is continuously gaining importance in processing of a wide variety of products, as it can modify physical, chemical and biological properties of the materials, including food and allied products on industrial scale due its inherent qualities like ease of processing in finally packaged form, eco-friendly nature and other obvious reasons over conventional means of processing. Food and allied products are either from agricultural produce or animal origin; they get easily contaminated from soil during harvesting, handling, processing, environment conditions, storage and transport from various types of micro-organisms including pathogens. In many countries it is mandatory to bring down the population of micro-organisms to an acceptable level and complete elimination of pathogens before such products are accepted for human or animal consumption. Processing of food and allied products by radiation has its own challenges due to wider public acceptance of irradiated food, a wide range, 0.25-50kGy, of absorbed dose requirements for different category of such products and purposes, use of a variety of packaging materials in different shapes and sizes and because of its perishable nature. More than 50 countries including India in the world have accepted radiation processing of food and allied products by radiation. Dosimetry is an important aspect of radiation processing, whether it is food or allied product. Uniformity in dose delivered to these products depends on several factors such as product carrier to source frame alignment, product carrier and product/tote box design, product loading pattern, attenuation due to product thickness, product bulk density that varies from 0.1-1.0 kg/l and the plant design whether during processing product overlaps the source or otherwise. In this presentation dosimetric aspects of radiation processing of food and allied products and problems associated with dosimetry of such

  8. Dosimetry through the Secondary Laboratory of Dosimetric Calibration of Mexico

    International Nuclear Information System (INIS)

    Tovar M, V.M.; Alvarez R, J.T.; Medina O, V.P.; Vergara M, F.; Anaya M, R.; Cejudo A, J.; Salinas L, B.

    2004-01-01

    In the beginnings of the sixty years an urgent necessity is presented mainly in the developing countries, of improving in important form the accuracy in the dosimetry of external faces in therapy of radiations (radiotherapy centers), mainly in the calibration of c linical dosemeters . In 1976 the International Atomic Energy Agency, (IAEA), and the World Health Organization, (WHO), they carried out a mutual agreement with regard to the establishment and operation of a net of Secondary Patron Laboratories of Dosimetry, (LSCD). The necessity to establish measure patterns in the field of the dosimetry of the ionizing radiations, is necessary, to have an accuracy but high in the dosimetry of the radiation beams in therapy which is highly dependent of the dose given to the tumor of those patient with cancer. Similar levels of accuracy are required in protection measures to the radiation with an acceptable smaller accuracy, however, when the personal dosemeters are used to determine the doses received by the individuals under work conditions, such mensurations in therapy of radiations and radiological protection will have traceability through a chain of comparisons to primary or national patterns. The traceability is necessary to assure the accuracy and acceptability of the dosimetric measures, as well as, the legal and economic implications. The traceability is also necessary in the dosimetry of high dose like in the sterilization of different products. The main function of the LSCD is to provide a service in metrology of ionizing radiations, maintaining the secondary or national patterns, which have a traceability to the International System of measures, which is based for if same in the comparison of patterns in the Primary Laboratories of Dosimetry (LPD) under the auspice of the International Office of Weights and Measure (BIPM). The secondary and national patterns in the LSCD constitute in Mexico, the national patterns of the magnitudes in the dosimetry of the

  9. Judgments of Discrete and Continuous Quantity: An Illusory Stroop Effect

    Science.gov (United States)

    Barth, Hilary C.

    2008-01-01

    Evidence from human cognitive neuroscience, animal neurophysiology, and behavioral research demonstrates that human adults, infants, and children share a common nonverbal quantity processing system with nonhuman animals. This system appears to represent both discrete and continuous quantity, but the proper characterization of the relationship…

  10. Effective utilisation of generation Y Quantity Surveyors | Van Eck ...

    African Journals Online (AJOL)

    In South Africa, 43% of all quantity surveyors are identified as generation Y, born between 1981 and 2000. This highlights the importance of generation Y to the Quantity Surveying (QS) profession, as they are the future upon which the QS profession will build. A lack of knowledge of the differences among generations can ...

  11. Variation in Quantity of Heat Produced from Charcoal of Prosopis ...

    African Journals Online (AJOL)

    Data were collected using the copper calorimeter, a thermometer, an air tight burner and a weight balance. The results showed a gradual decrease in the quantity of heat produced as combustion time increased from 10 40 minutes in all wood species. Significant differences (p<0.05) in the quantity of heat produced both ...

  12. Memory-Based Quantity Discrimination in Coyotes (Canis latrans

    Directory of Open Access Journals (Sweden)

    Salif Mahamane

    2014-08-01

    Full Text Available Previous research has shown that the ratio between competing quantities of food significantly mediates coyotes‘ (Canis latrans ability to choose the larger of two food options. These previous findings are consistent with predictions made by Weber‘s Law and indicate that coyotes possess quantity discrimination abilities that are similar to other species. Importantly, coyotes‘ discrimination abilities are similar to domestic dogs (Canis lupus familiaris, indicating that quantitative discrimination may remain stable throughout certain species‘ evolution. However, while previously shown in two domestic dogs, it is unknown whether coyotes possess the ability to discriminate visual quantities from memory. Here, we address this question by displaying different ratios of food quantities to 14 coyotes before placing the choices out of sight. The coyotes were then allowed to select one of either non-visible food quantities. Coyotes‘ discrimination of quantity from memory does not follow Weber‘s Law in this particular task. These results suggest that working memory in coyotes may not be adapted to maintain information regarding quantity as well as in domestic dogs. The likelihood of a coyote‘s choosing the large option increased when it was presented with difficult ratios of food options first, before it was later presented with trials using more easily discriminable ratios, and when the large option was placed on one particular side. This suggests that learning or motivation increased across trials when coyotes experienced difficult ratios first, and that location of food may have been more salient in working memory than quantity of food.

  13. Symbols and definitions of quantities and units in isotope stoichiometry

    International Nuclear Information System (INIS)

    Junghans, P.; Krumbiegel, P.; Faust, H.

    1982-01-01

    On the basis of the International System of Units and recent recommendations of the IUPAC on 'Symbols and Terminology for Physicochemical Quantities and Units' a system is proposed of uniform and unambiguous symbols and definitions of quantities and units used in the isotope dilution technique. The close relationship between isotope stoichiometry and common stoichiometry is demonstrated. (author)

  14. 41 CFR 109-27.102 - Economic order quantity principle.

    Science.gov (United States)

    2010-07-01

    ... PROCUREMENT 27-INVENTORY MANAGEMENT 27.1-Stock Replenishment § 109-27.102 Economic order quantity principle. ... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Economic order quantity principle. 109-27.102 Section 109-27.102 Public Contracts and Property Management Federal Property...

  15. 48 CFR 916.504 - Indefinite-quantity contracts.

    Science.gov (United States)

    2010-10-01

    ... indefinite-quantity, multiple award contracts to ensure that adequate consideration exists to contractually... contracts. 916.504 Section 916.504 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Indefinite-Delivery Contracts 916.504 Indefinite-quantity...

  16. 19 CFR 144.33 - Minimum quantities to be withdrawn.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Minimum quantities to be withdrawn. 144.33 Section 144.33 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT... Warehouse § 144.33 Minimum quantities to be withdrawn. Unless by special authority of the Commissioner of...

  17. 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.

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

    International Nuclear Information System (INIS)

    Cirrone, G.A.P.; Romano, F.; Scuderi, V.; Amato, A.; Candiano, G.; Cuttone, G.; Giove, D.; Korn, G.; Krasa, J.; Leanza, R.; Manna, R.; Maggiore, M.; Marchese, V.; Margarone, D.; Milluzzo, G.; Petringa, G.; Sabini, M.G.; Schillaci, F.

    2015-01-01

    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

  19. Characteristics of the Receptor for the Biosphere Model

    International Nuclear Information System (INIS)

    M.A. Wasiolek

    2005-01-01

    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

  20. 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.

  1. An approach for deriving growth equations for quantities exhibiting cumulative growth based on stochastic interpretation

    Science.gov (United States)

    Moriguchi, Kai

    2018-01-01

    Existing growth equations have been derived by hypothesizing the growth rate as self-referencing. Although that hypothesis is appropriate for quantities with growth directly restricted to themselves, it requires the solution of differential equations that are difficult to be derived. However, for quantities of growth that are indirectly related to themselves, and for quantities that exhibit cumulative growth, such as growth of diameter or volume of trees with lignification, ordinary growth models with assumptions that include self-referencing or implied catabolism terms might not be appropriate. For such quantities, the author proposes an approach for derivation of growth models based on stochastic and microscopic interpretation. Results show that ordinary growth models can be interpreted from the perspective. The approach enables one to derive growth functions without solving differential equations. Based on that approach, growth functions are derived by integrating cumulative distribution functions. Three growth functions are generated using reasonable probability distributions. The fitness of the generated growth functions for real diameter growth data was compared with that of generalized ordinary growth models. Results show that the presented approach has high ability to generate growth models that fit data much better than ordinary growth models for a given number of parameters.

  2. WEB TECHNOLOGIES USED TO FORECAST FUTURE WASTE QUANTITIES

    Directory of Open Access Journals (Sweden)

    Valeriu LUPU

    2014-06-01

    Full Text Available In this article the authors propose a modality of prognosis of the quantities of waste generated in a certain period. The proposition was finalized by achieving a model of prognosis present on a site hosted by a Web server. The software solve the problem for the general case, depending on the input data after analysis. After analyzing input data sets are used with one, two or three components (trend, seasonality and residual variable. According to the input data the adjustment model regarding the description of the analyzed phenomenon (additive and multiplying is chosen. If the chronogram of the analyzed phenomenon indicates an oscillating evolution, of sinusoidal nature, the additive model (+ is chosen, otherwise the multiplying model (  is chosen. The seasonal component is estimated and the deseasonalized chronological series is determined. The seasonality is determined by: the procedure of arithmetical means, the procedure of moving averages and the procedure of analytical tendency. The adjustment function is specified regarding the tendency of the phenomenon and its parameters are estimated. The significance of the adjustment function is verified specifying the significance threshold with which it may be accepted as significant. The estimation of the parameters of the adjustment function is made on the basis of the application of the method of least squares. The values of the phenomenon on two or three trimesters/ months are estimated for the processed data (by using time series with two or three steps ahead. Several types of waste specified by the value of the meter for waste from the database may be accepted. The model proposed makes decisions and justifies if the data prognosticated is accepted or not. All information from the input data to the final data is stored in a MySQL database.

  3. Dosimetric impact of gastrointestinal air column in radiation treatment of pancreatic cancer.

    Science.gov (United States)

    Estabrook, Neil C; Corn, Jonathan B; Ewing, Marvene M; Cardenes, Higinia R; Das, Indra J

    2018-02-01

    Dosimetric evaluation of air column in gastrointestinal (GI) structures in intensity modulated radiation therapy (IMRT) of pancreatic cancer. Nine sequential patients were retrospectively chosen for dosimetric analysis of air column in the GI apparatus in pancreatic cancer using cone beam CT (CBCT). The four-dimensional CT (4DCT) was used for target and organs at risk (OARs) and non-coplanar IMRT was used for treatment. Once a week, these patients underwent CBCT for air filling, isocentre verification and dose calculations retrospectively. Abdominal air column variation was as great as ±80% between weekly CBCT and 4DCT. Even with such a large air column in the treatment path for pancreatic cancer, changes in anteroposterior dimension were minimal (2.8%). Using IMRT, variations in air column did not correlate dosimetrically with large changes in target volume. An average dosimetric deviation of mere -3.3% and a maximum of -5.5% was observed. CBCT revealed large air column in GI structures; however, its impact is minimal for target coverage. Because of the inherent advantage of segmentation in IMRT, where only a small fraction of a given beam passes through the air column, this technique might have an advantage over 3DCRT in treating upper GI malignancies where the daily air column can have significant impact. Advances in knowledge: Radiation treatment of pancreatic cancer has significant challenges due to positioning, imaging of soft tissues and variability of air column in bowels. The dosimetric impact of variable air column is retrospectively studied using CBCT. Even though, the volume of air column changes by ± 80%, its dosimetric impact in IMRT is minimum.

  4. Applichation of the sulphate ceric dosimetric in the high doses range

    International Nuclear Information System (INIS)

    Prieto Miranda, F.

    1991-01-01

    The ceric-cerous dosimetric system is one of the system more employed in the high dose dosimetry. The spectrophotometric procedure to measure the ceric-concentration is an usual analityc method to determine the absorbed dose. On the other hand, due at increase employ of the irradiation process control. In this paper is realized the ceric-cerous dosimetric calibration in the dose range of 0,6 - 5 kGy and the application in the irradiation process control to differents absorbed dose values

  5. EPR/UV study of dosimetric properties for gamma-irradiated saccharose at 77 K

    International Nuclear Information System (INIS)

    Juarez Calderon, J.M.; Negron Mendoza, A.; Ramos Bernal, S.; Gomez Vidales, V.

    2008-01-01

    Saccharose, as table sugar, has been considered as a promising dosimetric organic material for EPR and UV readings because of the free radicals produced due to irradiation with X and gamma rays. Nevertheless, most studies with this system have been carried out at room temperature. We studied the EPR/UV response to gamma rays for this dosimetric system at low temperature (77 K) in order to investigate if a dependence of irradiation temperature exists. Dose effect, fading characteristics and dose coefficient have been also studied. (author)

  6. Improvement in the dosimetric CaSO4: Dy obtention method

    International Nuclear Information System (INIS)

    Campos, L.L.; Frutuoso, P.H.; Souto, V.J.

    1989-08-01

    With the purpose of saving up in the dosimetric CaSO 4 : Dy production, a new method was developed to obtain single crystals. In this method the nitrogen flux used to carry the acid vapour was substituted by compressed air. It was compared all dosimetric properties of the crystals. There is no alteration in the glow curve. The sensitivity is the same in both cases and the lower detection limit is 3.8 x 10 -8 C.Kg -1 (150 μR) [pt

  7. 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.

  8. 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.

  9. Concept of ICRU's operational quantity and its application

    International Nuclear Information System (INIS)

    Murakami, Hiroyuki

    1995-01-01

    The operational quantity which was introduced in the ICRU report 39 published in 1985 was shocking rather than fresh for the author. The report was translated into Japanese, but at the beginning, the contents were not able to be understood. Thereafter, the measurement of ICRU sphere dose equivalent was introduced in a national law. But it is feared that the understanding of this operational quantity is limited to specialist level, and is not by men of practical works. The meaning of ''operational'' must be that workers measure and obtain dose on the spot for the radiation protection for themselves. The principles used when ICRU considered the new practical measured quantity are shown. In the definition of operational quantity in area monitoring, two concepts of expanded and aligned connect real measurement with the operational quantity. The problems of measuring individual dose equivalent are discussed. As to the reality of applying the operational quantity, the fundamentals of the calibration of measuring instruments, the investigation of the operational quantity in relation to measuring instruments and measurement mode, and the relation of area monitoring and individual monitoring are described. (K.I.)

  10. Dosimetric references for low and medium energy X rays at the LNE-LHB: X ray spectrum simulation and calculation of corrective factors using the Monte Carlo method

    International Nuclear Information System (INIS)

    Ksouri, W.; Gouriou, J.; Denoziere, M.

    2010-01-01

    As the LNHB (Laboratoire National Henri Becquerel) has set dosimetric references for low and medium energy X rays in medical and industrial applications, the authors report the determination of different corrective factors: those related to the mechanical realization of the ionization chamber, and those related to physical phenomena in this room (electron loss or Ke, and photon diffusion or Ksc). These factors are computed using the Monte Carlo PENELOPE code. As the determination of Ke and Ksc requires the knowledge of the energy spectral distribution of impinging photons, and as spectrum measurement exhibit ambiguities, spectra are determined through a Monte Carlo simulation using PENELOPE and EGS codes, by modelling the X ray tube

  11. Symmetry, Reference Frames, and Relational Quantities in Quantum Mechanics

    Science.gov (United States)

    Loveridge, Leon; Miyadera, Takayuki; Busch, Paul

    2018-02-01

    We propose that observables in quantum theory are properly understood as representatives of symmetry-invariant quantities relating one system to another, the latter to be called a reference system. We provide a rigorous mathematical language to introduce and study quantum reference systems, showing that the orthodox "absolute" quantities are good representatives of observable relative quantities if the reference state is suitably localised. We use this relational formalism to critique the literature on the relationship between reference frames and superselection rules, settling a long-standing debate on the subject.

  12. 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.

  13. Theoretical and experimental determination of dosimetric characteristics for ADVANTAGETM Pd-103 brachytherapy source

    International Nuclear Information System (INIS)

    Meigooni, Ali S.; Dini, Sharifeh A.; Awan, Shahid B.; Dou, Kai; Koona, Rafiq A.

    2006-01-01

    ADVANTAGE TM Pd-103 brachytherapy source has been recently introduced by IsoAid 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 TM using LiF TLD chips and the theoretical calculations were performed in Solid Water 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 -1 U -1 in liquid water and 0.67 cGy h -1 U -1 in Solid Water TM medium. The measured dose rate constant in Solid Water TM was found to be 0.68±8% cGy h -1 U -1 , which is in a good agreement (within ±5%) to the Monte Carlo simulated data. The 2D- and 1D-anisotropy functions of the ADVANTAGE 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 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

  14. Dosimetric characteristics of a reusable 3D radiochromic dosimetry material.

    Directory of Open Access Journals (Sweden)

    Jong Min Park

    Full Text Available To investigate the dosimetric characteristics of PRESAGEREU dosimeters.Commercially available PRESAGEREU dosimeters (size of 10 mm × 10 mm × 45 mm were divided into two groups, with one of the groups placed at room temperature of 22°C (RT group and another group placed at low temperature of 10°C (LT group. A total of 3 dosimeters (set of dosimeters were irradiated at a time, with doses of 1 Gy, 2 Gy, 4 Gy, 8 Gy, 12 Gy, 16 Gy, and 20 Gy, at a nominal dose rate of 400 MU/min at temperature of 22°C. The dosimeters were irradiated three additional times by delivering the same doses as those during the initial irradiations (4 irradiation cycles. Optical density (OD was assessed using optical CT scanning.Considering both linearity and sensitivity of the OD curves, R2 above 0.95 and sensitivity above 0.04 ΔOD/Gy were observed at the 1st irradiation (reading time ≤ 6 h and 2nd irradiation (reading time = 0.5 h for the RT group. For the LT group, those values were observed at the 1st irradiation (reading time ≤ 2 h, and the 3rd and 4th irradiations (both reading times = 0.5 h. Considering the reproducibility of signals in response to the same dose, dosimeters in the RT group showed average deviations among dosimeters less than 5% (the 1st and 2nd irradiations at the reading time of 0.5 h, while for dosimeters in the LT group showed average deviations among dosimeters less than 6% (the 3rd and 4th irradiations at the reading time of 0.5 h. For the rest, the OD curves were not linear, sensitivities of the dosimeters were lower than 0.04 ΔOD/Gy, and OD deviations at the same dose were larger than 6%.At room temperature, PRESAGEREU dosimeters could be used for dose measurement only for up to two dose measurement sessions. At low temperatures, usage of PRESAGEREU dosimeters for dose measurement seems to be possible from the 3rd irradiation. When reusing PRESAGEREU dosimeters, the OD curve should be re-defined for every measurement session because

  15. Study of the dosimetric properties using organometallic polymers in solution

    International Nuclear Information System (INIS)

    Fernandes, David Moreira

    2012-01-01

    This work aimed to study the dosimetric characteristics of the polymer of the polymer ''poly-[ 1, l-bis (ethynyl) -4,4-biphenyl (bis-tributylphosphine) Pt (11)]'' (Pt-DEBP) compared to radiation gamma. The Pt-DEBP polymer, containing ten monomer units, was then dissolved in organic solvents as chloroform and toluene. The samples were irradiated at four concentrations (0.0500, 0.0375, 0.0250, 0.0113 mg / mL) in duplicate, with radiation doses ranging from 1 to 90 Gy. The results were evaluated based on spectroscopic techniques such as optical absorption spectroscopy (UV -Vis), fluorescence (emission), time resolved fluorescence (FRT) and Fourier transform infrared (FTIR). For DEBP-Pt solutions in chloroform, there is a shift in the position of the main optical absorption band (πt - π*) to lower wavelength (blue-shift), allied to a decreasing absorption intensity with increasing radiation dose. In fluorescence spectroscopy, there was a shift to longer wavelengths (redshift) allied to an increasing emission intensity with increasing radiation dose. FRT experiments on irradiated samples dissolved in chloroform indicated the presence of a new emitter center. FTIR spectra show the incorporation of chlorine in the polymer chain, justifying the blue-shift observed in the absorption spectra and the new emission center. In addition, the behavior of linear results in the absorption and fluorescence studies was investigated based on the relationship between the wavelength of maximum absorption/emission and the radiation dose. For both cases, a linear behavior was observed in relation to the sample concentration. Repeatability and stability tests were also performed. For the samples dissolved in toluene, there was no significant shift of the spectrum of absorption or fluorescence for all doses. The results show that the Pt-DEBP polymer dissolved in chloroform can be used as a dosimeter for x-ray doses between 1 - 30 Gy based on the changes in absorption and/or emission

  16. Quantitative dosimetric verification of an IMRT planning and delivery system

    International Nuclear Information System (INIS)

    Low, D.A.; Mutic, S.; Dempsey, J.F.; Gerber, R.L.; Bosch, W.R.; Perez, C.A.; Purdy, J.A.

    1998-01-01

    Background and purpose: The accuracy of dose calculation and delivery of a commercial serial tomotherapy treatment planning and delivery system (Peacock, NOMOS Corporation) was experimentally determined. Materials and methods: External beam fluence distributions were optimized and delivered to test treatment plan target volumes, including three with cylindrical targets with diameters ranging from 2.0 to 6.2 cm and lengths of 0.9 through 4.8 cm, one using three cylindrical targets and two using C-shaped targets surrounding a critical structure, each with different dose distribution optimization criteria. Computer overlays of film-measured and calculated planar dose distributions were used to assess the dose calculation and delivery spatial accuracy. A 0.125 cm 3 ionization chamber was used to conduct absolute point dosimetry verification. Thermoluminescent dosimetry chips, a small-volume ionization chamber and radiochromic film were used as independent checks of the ion chamber measurements. Results: Spatial localization accuracy was found to be better than ±2.0 mm in the transverse axes (with one exception of 3.0 mm) and ±1.5 mm in the longitudinal axis. Dosimetric verification using single slice delivery versions of the plans showed that the relative dose distribution was accurate to ±2% within and outside the target volumes (in high dose and low dose gradient regions) with a mean and standard deviation for all points of -0.05% and 1.1%, respectively. The absolute dose per monitor unit was found to vary by ±3.5% of the mean value due to the lack of consideration for leakage radiation and the limited scattered radiation integration in the dose calculation algorithm. To deliver the prescribed dose, adjustment of the monitor units by the measured ratio would be required. Conclusions: The treatment planning and delivery system offered suitably accurate spatial registration and dose delivery of serial tomotherapy generated dose distributions. The quantitative dose

  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. SU-F-T-467: A Cross-Checking Approach for Dosimetric Verification of Beam- Matched Elekta Linear Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Y; Yuan, J; Geis, P; Colussi, V; Machtay, M; Ellis, R; Wessels, B [University Hospitals Case Medical Center, Dept of Radiation Oncology, Cleveland, OH (United States)

    2016-06-15

    Purpose: To verify the similarity of the dosimetric characteristics between two Elekta linear accelerators (linacs) in order to treat patients interchangeably on these two machines without re-planning. Methods: To investigate the viability of matching the 6 MV flattened beam on an existing linac (Elekta Synergy with Agility head) with a recently installed new linca (Elekta Versa HD), percent depth doses (PDD), flatness and symmetry output factors were compared for both machines. To validate the beam matching among machines, we carried out two approaches to cross-check the dosimetrical equivalence: 1) the prior treatment plans were re-computed based on the newly built Versa HD treatment planning system (TPS) model without changing the beam control points; 2) The same plans were delivered on both machines and the radiation dose measurements on a MapCheck2 were compared with TPS calculations. Three VMAT plans (Head and neck, lung, and prostate) were used in the study. Results: The difference between the PDDs for 10×10 cm{sup 2} field at all depths was less than 0.8%. The difference of flatness and symmetry for 30×30 cm{sup 2} field was less than 0.8%, and the measured output factors varies by less than 1% for each field size ranging from 2×2 cm2 to 40×40 cm{sup 2}. For the same plans, the maximum difference of the two calculated dose distributions is 2% of prescription. For the QA measurements, the gamma index passing rates were above 99% for 3%/3mm criteria with 10% threshold for all three clinical plans. Conclusion: A beam modality matching between two Elekta linacs is demonstrated with a cross-checking approach.

  19. SU-F-T-649: Dosimetric Evaluation of Non-Coplanar Arc Therapy Using a Novel Rotating Gamma Ray System

    Energy Technology Data Exchange (ETDEWEB)

    Eldib, A; Chibani, O; Jin, L; Fan, J; Veltchev, I; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States); Mora, G [Universidade de Lisboa, Codex, Lisboa (Portugal); Li, J [Cyber Medical Inc, Xian, Shaanxi (China)

    2016-06-15

    Purpose: Stereotactic intra and extra-cranial body radiation therapy has evolved with advances in treatment accuracy, effective radiation dose, and parameters necessary to maximize machine capabilities. Novel gamma systems with a ring type gantry were developed having the ability to perform oblique arcs. The aim of this study is to explore the dosimetric advantages of this new system. Methods: The rotating Gamma system is named CybeRay (Cyber Medical Corp., Xian, China). It has a treatment head of 16 cobalt-60 sources focused to the isocenter, which can rotate 360° on the ring gantry and swing 35° in the superior direction. Treatment plans were generated utilizing our in-house Monte Carlo treatment planning system. A cylindrical phantom was modeled with 2mm voxel size. Dose inside the cylindrical phantom was calculated for coplanar and non-coplanar arcs. Dosimetric differences between CybeRay cobalt beams and CyberKnife 6MV beams were compared in a lung phantom and for previously treated SBRT patients. Results: The full width at half maxima of cross profiles in the S-I direction for the coplanar setup matched the cone sizes, while for the non-coplanar setup, FWHM was larger by 2mm for a 10mm cone and about 5mm for larger cones. In the coronal and sagittal view, coplanar beams showed elliptical shaped isodose lines, while non-coplanar beams showed circular isodose lines. Thus proper selection of the oblique angle and cone size can aid optimal dose matching to the target volume. Comparing a single 5mm cone from CybeRay to that from CyberKnife showed similar penumbra in a lung phantom but CybeRay had significant lower doses beyond lung tissues. Comparable treatment plans were obtained with CybeRay as that from CyberKnife.ConclusionThe noncoplanar multiple source arrangement of CybeRay will be of great clinical benefits for stereotactic intra and extra-cranial radiation therapy.

  20. SU-F-T-467: A Cross-Checking Approach for Dosimetric Verification of Beam- Matched Elekta Linear Accelerators

    International Nuclear Information System (INIS)

    Zheng, Y; Yuan, J; Geis, P; Colussi, V; Machtay, M; Ellis, R; Wessels, B

    2016-01-01

    Purpose: To verify the similarity of the dosimetric characteristics between two Elekta linear accelerators (linacs) in order to treat patients interchangeably on these two machines without re-planning. Methods: To investigate the viability of matching the 6 MV flattened beam on an existing linac (Elekta Synergy with Agility head) with a recently installed new linca (Elekta Versa HD), percent depth doses (PDD), flatness and symmetry output factors were compared for both machines. To validate the beam matching among machines, we carried out two approaches to cross-check the dosimetrical equivalence: 1) the prior treatment plans were re-computed based on the newly built Versa HD treatment planning system (TPS) model without changing the beam control points; 2) The same plans were delivered on both machines and the radiation dose measurements on a MapCheck2 were compared with TPS calculations. Three VMAT plans (Head and neck, lung, and prostate) were used in the study. Results: The difference between the PDDs for 10×10 cm 2 field at all depths was less than 0.8%. The difference of flatness and symmetry for 30×30 cm 2 field was less than 0.8%, and the measured output factors varies by less than 1% for each field size ranging from 2×2 cm2 to 40×40 cm 2 . For the same plans, the maximum difference of the two calculated dose distributions is 2% of prescription. For the QA measurements, the gamma index passing rates were above 99% for 3%/3mm criteria with 10% threshold for all three clinical plans. Conclusion: A beam modality matching between two Elekta linacs is demonstrated with a cross-checking approach.

  1. Biokinetic and dosimetric studies of 188Re-hyaluronic acid: a new radiopharmaceutical for treatment of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Melendez-Alafort, Laura; Nadali, Anna; Zangoni, Elena; Banzato, Alessandra; Rondina, Maria; Rosato, Antonio; Mazzi, Ulderico

    2009-01-01

    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: 188 Re-HA was prepared by a direct labelling method to produce a ReO(O-COO) 2 -type coordination complex. 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 188 Re-HA was determined. Results: A stable complex of 188 Re-HA was obtained with high radiochemical purity (>90%) and low serum protein binding (2%). Biokinetic studies showed a rapid blood clearance (T 1/2 α=21 min). Four hours after administration, 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 ∼40 Gy after 7.4 MBq of 188 Re-HA injection. Conclusions: 188 Re-HA complex showed good stability, pharmacokinetic and dosimetric characteristics that confirm its potential as a new agent for HCC radiation therapy.

  2. 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.

  3. Agreement Between Institutional Measurements and Treatment Planning System Calculations for Basic Dosimetric Parameters as Measured by the Imaging and Radiation Oncology Core-Houston

    International Nuclear Information System (INIS)

    Kerns, James R.; Followill, David S.; Lowenstein, Jessica; Molineu, Andrea; Alvarez, Paola; Taylor, Paige A.; Kry, Stephen F.

    2016-01-01

    Purpose: To compare radiation machine measurement data collected by the Imaging and Radiation Oncology Core at Houston (IROC-H) with institutional treatment planning system (TPS) values, to identify parameters with large differences in agreement; the findings will help institutions focus their efforts to improve the accuracy of their TPS models. Methods and Materials: Between 2000 and 2014, IROC-H visited more than 250 institutions and conducted independent measurements of machine dosimetric data points, including percentage depth dose, output factors, off-axis factors, multileaf collimator small fields, and wedge data. We compared these data with the institutional TPS values for the same points by energy, class, and parameter to identify differences and similarities using criteria involving both the medians and standard deviations for Varian linear accelerators. Distributions of differences between machine measurements and institutional TPS values were generated for basic dosimetric parameters. Results: On average, intensity modulated radiation therapy–style and stereotactic body radiation therapy–style output factors and upper physical wedge output factors were the most problematic. Percentage depth dose, jaw output factors, and enhanced dynamic wedge output factors agreed best between the IROC-H measurements and the TPS values. Although small differences were shown between 2 common TPS systems, neither was superior to the other. Parameter agreement was constant over time from 2000 to 2014. Conclusions: Differences in basic dosimetric parameters between machine measurements and TPS values vary widely depending on the parameter, although agreement does not seem to vary by TPS and has not changed over time. Intensity modulated radiation therapy–style output factors, stereotactic body radiation therapy–style output factors, and upper physical wedge output factors had the largest disagreement and should be carefully modeled to ensure accuracy.

  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. On Complex Networks Representation and Computation of Hydrologycal Quantities

    Science.gov (United States)

    Serafin, F.; Bancheri, M.; David, O.; Rigon, R.

    2017-12-01

    Water is our blue gold. Despite results of discovery-based science keep warning public opinion about the looming worldwide water crisis, water is still treated as a not worth taking resource. Could a different multi-scale perspective affect environmental decision-making more deeply? Can also a further pairing to a new graphical representation of processes interaction sway decision-making more effectively and public opinion consequently?This abstract introduces a complex networks driven way to represent catchments eco-hydrology and related flexible informatics to manage it. The representation is built upon mathematical category. A category is an algebraic structure that comprises "objects" linked by "arrows". It is an evolution of Petri Nets said Time Continuous Petri Nets (TCPN). It aims to display (water) budgets processes and catchment interactions using explicative and self-contained symbolism. The result improves readability of physical processes compared to current descriptions. The IT perspective hinges on the Object Modeling System (OMS) v3. The latter is a non-invasive flexible environmental modeling framework designed to support component-based model development. The implementation of a Directed Acyclic Graph (DAG) data structure, named Net3, has recently enhanced its flexibility. Net3 represents interacting systems as complex networks: vertices match up with any sort of time evolving quantity; edges correspond to their data (fluxes) interchange. It currently hosts JGrass-NewAge components, and those implementing travel time analysis of fluxes. Further bio-physical or management oriented components can be easily added.This talk introduces both graphical representation and related informatics exercising actual applications and examples.

  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.

    Science.gov (United States)

    Thrapsanioti, Zoi; Karanasiou, Irene; Platoni, Kalliopi; Efstathopoulos, Efstathios P; Matsopoulos, George; Dilvoi, Maria; Patatoukas, George; Chaldeopoulos, Demetrios; Kelekis, Nikolaos; Kouloulias, Vassilis

    2013-01-01

    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. 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. Concerning the prostate radiotherapy, there was a significant correlation between RTOG acute rectal toxicity and D50 (P parameters, calculated for α/β = 10 Gy. Moreover, concerning the breast radiotherapy there was a significant correlation between RTOG skin toxicity and V(≥60) dosimetric parameter, calculated for both α/β = 2.3 Gy (P < 0.001) and α/β = 10 Gy (P < 0.001). The new tool seems reliable and user-friendly. 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. Quantity and Quality of Inhaled Dose Predicts Immunopathology in Tuberculosis

    Directory of Open Access Journals (Sweden)

    Kevin Patrick Fennelly

    2015-06-01

    Full Text Available Experimental animal models of tuberculosis (TB have convincingly demonstrated that inhaled dose predicts immunopathology and survival. In contrast, the importance of inhaled dose has generally not been appreciated in TB epidemiology, clinical science, or the practice of TB control. Infectiousness of TB patients has traditionally been assessed using microscopy for acid-fast bacilli in the sputum, which should be considered only a risk factor. We have recently demonstrated that cough aerosol cultures from index cases with pulmonary TB are the best predictors of new infection among household contacts. We suggest that cough aerosols of M. tuberculosis are the best surrogates of inhaled dose, and we hypothesize that the quantity of cough aerosols is associated with TB infection versus disease. Although several factors affect the quality of infectious aerosols, we propose that the particle size distribution of cough aerosols is an important predictor of primary upper airway disease and cervical lymphadenitis and of immune responses in exposed hosts. We hypothesize that large droplet aerosols (> 5 microns containing M. tuberculosis deposit in the upper airway and can induce immune responses without establishing infection. We suggest that this may partially explain the large proportion of humans who never develop TB disease in spite of having immunological evidence of M. tuberculosis infection (e.g. positive TST or IGRA. If these hypotheses are proven true, they would alter the current paradigm of latent TB infection and reactivation, further demonstrating the need for better biomarkers or methods of assessing TB infection and the risk of developing disease.

  8. 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.)

  9. A comparison of methods for representing sparsely sampled random quantities.

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Vicente Jose; Swiler, Laura Painton; Urbina, Angel; Mullins, Joshua

    2013-09-01

    This report discusses the treatment of uncertainties stemming from relatively few samples of random quantities. The importance of this topic extends beyond experimental data uncertainty to situations involving uncertainty in model calibration, validation, and prediction. With very sparse data samples it is not practical to have a goal of accurately estimating the underlying probability density function (PDF). Rather, a pragmatic goal is that the uncertainty representation should be conservative so as to bound a specified percentile range of the actual PDF, say the range between 0.025 and .975 percentiles, with reasonable reliability. A second, opposing objective is that the representation not be overly conservative; that it minimally over-estimate the desired percentile range of the actual PDF. The presence of the two opposing objectives makes the sparse-data uncertainty representation problem interesting and difficult. In this report, five uncertainty representation techniques are characterized for their performance on twenty-one test problems (over thousands of trials for each problem) according to these two opposing objectives and other performance measures. Two of the methods, statistical Tolerance Intervals and a kernel density approach specifically developed for handling sparse data, exhibit significantly better overall performance than the others.

  10. Safeguards Implementation Guide for States with Small Quantities Protocols

    International Nuclear Information System (INIS)

    2013-01-01

    The International Atomic Energy Agency (IAEA) works to enhance the contribution of nuclear energy for peace and prosperity around the world, while helping to ensure that nuclear material is not diverted to nuclear weapons or other nuclear explosive devices. In implementing safeguards, the IAEA plays an instrumental independent verification role, providing credible assurances that States' safeguards commitments are being respected. Most of the world's non-nuclear-weapon States (NNWSs) have concluded comprehensive safeguards agreements (CSAs) with the IAEA, pursuant to the Treaty on the Non- Proliferation of Nuclear Weapons (NPT). The IAEA and States are required to cooperate in the implementation of such agreements. Effective cooperation demonstrates a State's commitment to the peaceful use of nuclear energy and furthers the State's national interests by reducing the risk of unauthorized use of nuclear material. Over 100 NNWSs party to the NPT have very limited quantities of nuclear material and have concluded protocols to their CSAs which hold in abeyance many procedures in Part II of a CSA. These protocols are referred to as 'small quantities protocols' or 'SQPs' and remain in effect as long as the State meets certain eligibility criteria. The purpose of an SQP is to reduce the burden of safeguards implementation for States with little or no nuclear activities, while retaining the integrity of the safeguards system. States with SQPs have very important obligations they must fulfil under their CSAs. In 1997, as part of the IAEA's efforts to strengthen its safeguards system, the Model Additional Protocol to the Agreement(s) between State(s) and the International Atomic Energy Agency for the Application of Safeguards was developed to provide the IAEA with broader access to information and locations, thus significantly increasing the IAEA's ability to provide assurance of the absence of undeclared nuclear material and activities in States. Many States with SQPs have

  11. Symmetries as by-products of conserved quantities

    Science.gov (United States)

    Romero-Maltrana, Diego

    2015-11-01

    There is general consensus among physicists in considering symmetries as a source of conserved quantities, a conclusion allegedly supported by Emmy Noether's theorems. Recently it has been pointed out that no arrow of explanation can be extracted from Noether's work, and there are also criticisms against the priority of particular symmetries over specific conserved quantities under Noether's ideas, but there are no general arguments against the aforementioned consensus, nor proposals promoting an explanation that leads from conserved quantities to symmetries. In this paper a general argument is built which favours conserved quantities over symmetries inasmuch as the presence of the former seems to allow (i.e. it seems to be a sufficient condition leading to) symmetrical descriptions.

  12. Harassment and discrimination experienced by quantity surveyors in ...

    African Journals Online (AJOL)

    . P Bowen, P Edwards, H Lingard, K Cattell. Abstract. This article examines the workplace discrimination and harassment experiences of professional quantity surveyors in South Africa and explores the relationship between harassment, ...

  13. A note on the expectation and deviation of physical quantities

    International Nuclear Information System (INIS)

    Nagasawa, Masao

    2009-01-01

    By using the function representation of self-adjoint operators, the expectation and variance of physical quantities (self-adjoint operators) are defined, and it is shown that the so-called uncertainty principle does not hold.

  14. Foreign materials in the repository - update of estimated quantities

    International Nuclear Information System (INIS)

    Hagros, A.

    2007-03-01

    In a repository for spent nuclear fuel, a variety of materials are used during the construction process and during the operation of the repository. In addition to materials necessary for the construction and operation, some materials may be transported into the repository through the ventilation air, as emissions from vehicles, as waste produced by the staff etc. Both of these two types of materials are considered here and their quantities - both the introduced quantities and the quantities that remain after closure - in the repository constructed at Olkiluoto in Eurajoki, Finland are estimated here based on new information. This work is intended to update the estimations that have been made previously, and it takes advantage of the experience collected during the construction of the underground rock characterisation facility ONKALO at Olkiluoto. During this construction process, the quantities of the different construction materials introduced into the underground openings have been monitored and they form a basis for estimating the quantities to be used in the future. The estimations made in this report are specific to a KBS-3V type repository and to the Olkiluoto site, although in some cases more generic information has been used, particularly when the relevant quantities have not been monitored in the ONKALO. The estimations are based on the new repository layout produced in 2006 and consider the latest plans for grouting and rock support. As these plans are generally not final yet, several different alternative plans are assumed when necessary. Also two different strategies for the backfilling of the tunnels are considered. The most significant differences with respect to the results of an earlier estimation are related to the materials used in grouting, shotcreting and in support bolts. In the cases where a mixture of bentonite and crushed rock is the used backfill alternative, gypsum and cement are the materials with the largest quantities remaining in the

  15. The learning climate of chartered quantity surveying practices

    OpenAIRE

    Lowe, David; Skitmore, Martin

    2011-01-01

    This paper reports on a fully structured interview survey investigating the relationship between the learning climate of chartered quantity surveying practices and individual learning styles, approaches to learning, ability, measures of length of service and the size of the quantity surveying organisation. The results indicate that the learning environment is generally supportive in terms of human support, but less supportive in terms of staff development systems; as individuals rise in the h...

  16. Import and export of small quantities of nuclear materials

    International Nuclear Information System (INIS)

    Grenier, M.

    1986-06-01

    Administrative procedures for import export of nuclear materials are specific for each country. In France regulations are reviewed for small quantities, lower threshold, in some cases, allows a simplified procedure, however thresholds are not the same in the different texts (and for one of them, concerning proliferation, is zero). It is obvious that regulations are necessary even for small quantities but national and international threshold should be harmonized [fr

  17. Information quantity in a pixel of digital image

    OpenAIRE

    Kharinov, M.

    2014-01-01

    The paper is devoted to the problem of integer-valued estimating of information quantity in a pixel of digital image. The definition of an integer estimation of information quantity based on constructing of the certain binary hierarchy of pixel clusters is proposed. The methods for constructing hierarchies of clusters and generating of hierarchical sequences of image approximations that minimally differ from the image by a standard deviation are developed. Experimental results on integer-valu...

  18. 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.

  19. Using Bayesian logistic regression to evaluate a new type of dosimetric constraint for prostate radiotherapy treatment planning.

    Science.gov (United States)

    Buettner, F; Gulliford, S L; Webb, S; Partridge, M

    2010-04-01

    RT01 trial. The predictive power was quantified using receiver-operator characteristic (ROC) curves. Toxicities considered were rectal bleeding, loose stools, and a global toxicity score. Dose-volume constraints had less predictive power than the new type of hybrid constraints. A probabilistic model for predicting rectal bleeding based on the dose-volume constraints proposed by other researchers [C. Fiorino, G. Fellin, T. Rancati, V. Vavassori, C. Bianchi, V. C. Borca, G. Girelli, M. Mapelli, L. Menegotti, S. Nava, and R. Valdagni, "Clinical and dosimetric predictors of late rectal syndrome after 3D-CRT for localized prostate cancer: Preliminary results of a multicenter prospective study," Int. J. Radiat. Oncol., Biol., Phys. 70, 1130-1137 (2008)], the CHHiP dose-volume constraints, the RT01-based dose-volume constraints, and the hybrid constraints resulted in average areas under the ROC curves of 0.56, 0.58, 0.62, and 0.67, respectively. For predicting loose stools, the corresponding values were 0.57, 0.53, 0.66, and 0.71, respectively. The areas under the respective ROC curves for predicting the global toxicity score were 0.58, 0.55, 0.61, and 0.63. Thus, imposing the new type of hybrid constraints when generating a treatment plan should result in a reduction in the incidence of radiation-induced late rectal toxicity.

  20. Dosimetric evaluation of prostate rotations and their correction by couch rotations

    NARCIS (Netherlands)

    van Herten, Yvonne R. J.; van de Kamer, Jeroen B.; van Wieringen, Niek; Pieters, Bradley R.; Bel, Arjan

    2008-01-01

    PURPOSE: To investigate the dosimetric effect of prostate rotations and limited on-line corrections by couch rotations (

  1. Geometric factors influencing dosimetric sparing of the parotid glands using IMRT

    International Nuclear Information System (INIS)

    Hunt, Margie A.; Jackson, Andrew; Narayana, Ashwatha; Lee, Nancy

    2006-01-01

    Purpose/Objective: To determine the relationship between the parotid volume, parotid-planning target volume (PTV) overlap, and dosimetric sparing of the parotid with intensity-modulated radiation therapy (IMRT). Methods and Materials: Parotid data were collected retrospectively for 51 patients treated with simultaneous boost IMRT. Unresectable patients received 54 or 59.4 Gy to subclinical disease, 70 Gy to gross disease. Patients treated postoperatively received 54, 60, and 66 Gy to low-risk, high-risk, and tumor bed regions. Volume and mean dose of each gland and gland segments outside of and overlapping the PTV were collected. Proximity of each gland to each PTV was recorded. Results: Dosimetric sparing (mean dose ≤26.5 Gy) was achieved in 66 of 71 glands with ≤21% parotid-PTV overlap and 8 of 23 glands with >21% overlap (p = 21%. Median mean dose was 25.9 Gy to glands overlapping PTV 54 or PTV 59 alone and 30.0 Gy to those abutting PTV 7 (p 7 was associated with higher parotid dose, satisfactory sparing was achieved in 24 of 43 ipsilateral glands. Conclusions: Dosimetric sparing of the parotid is feasible when the parotid-PTV overlap is less than approximately 20%. With more overlap, sparing may result in low doses within the overlap region, possibly leading to inadequate PTV coverage. Gland proximity to the high-dose PTV is associated with higher mean dose but does not always preclude dosimetric sparing

  2. Dosimetric Advantages of Midventilation Compared With Internal Target Volume for Radiation Therapy of Pancreatic Cancer

    NARCIS (Netherlands)

    Lens, Eelco; van der Horst, Astrid; Versteijne, Eva; van Tienhoven, Geertjan; Bel, Arjan

    2015-01-01

    The midventilation (midV) approach can be used to take respiratory-induced pancreatic tumor motion into account during radiation therapy. In this study, the dosimetric consequences for organs at risk and tumor coverage of using a midV approach compared with using an internal target volume (ITV) were

  3. The features of radiation induced lung fibrosis related with dosimetric parameters

    International Nuclear Information System (INIS)

    Oh, Young-Taek; Noh, O Kyu; Jang, Hyunsoo; Chun, Mison; Park, Kyung Joo; Park, Kwang Joo; Kim, Mi-Hwa; Park, Hae-Jin

    2012-01-01

    Background and purpose: Radiation induced lung fibrosis (RILF) is a major complication after lung irradiation and is very important for long term quality of life and could result in fatal respiratory insufficiency. However, there has been little information on dosimetric parameters for radiotherapy planning in the aspect of RILF. The features of RILF related with dosimetric parameters were evaluated. Methods and materials: Forty-eight patients with non-small cell lung carcinoma who underwent post-operative radiation therapy (PORT) without adjuvant chemotherapy were analyzed. The degree of lung fibrosis was estimated by fibrosis volume and the dosimetric parameters were calculated from the plan of 3-dimensional conformal radiotherapy. Results: The fibrosis volume and V-dose as dosimetric parameters showed significant correlation and the correlation coefficient ranged from 0.602 to 0.683 (P < 0.01). The degree of the correlation line was steeper as the dose increase and threshold dose was not found. Mean lung dose (MLD) showed strong correlation with fibrosis volume (correlation coefficient = 0.726, P < 0.01). Conclusions: The fibrosis volume is continuously increased with V-dose as the reference dose increases. MLD is useful as a single parameter for comparing rival plans in the aspect of RILF.

  4. 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 Coun...

  5. 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

    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-absorption...

  6. Compartmental and dosimetric studies of anti-CD20 labelled with 188Re

    International Nuclear Information System (INIS)

    Kuramoto, Graciela Barrio

    2016-01-01

    The radioimmunotherapy (RIT) uses MAbs conjugated to radionuclides α or β - emitters, both for therapy. Your treatment is based on the irradiation and tumor destruction, preserving the normal organs as the excess radiation. Radionuclides β - emitters as 131 I, 90 Y, 188 Re 177 Lu and are useful for the development of therapeutic radiopharmaceuticals and, when coupled with MAb and Anti-CD20 it is important mainly for the treatment of non-Hodgkin's lymphomas (NHL). 188 Re (E β = 2.12 MeV; E γ = 155 keV; t1/2 = 16.9 h) is an attractive radionuclide for RIT. However, 188 Re can be obtained from a radionuclide generator of 188 W/ 188 Re, commercially available, making it convenient for use in research and for clinical routine. The CR of IPEN has a project aimed at the production of radiopharmaceutical 188 Re-Anti-CD20, where the radionuclide can be obtained from a generator system 188 W/ 188 Re. With this proposed a study to assess the efficiency of this labeling technique for treatment in accordance compartmental and dosimetry. The objective of this study was to compare the marking of anti-CD20 MAb with 188 Re with the marking of the antibody with 90 Y, 131 I, 177 Lu and 99m Tc (for their similar chemical characteristics) and 211 At, 213 Bi, 223 Ra and 225 Ac); through the study of labeling techniques reported in literature, the proposal of a compartmental model to evaluate its pharmacokinetic and dosimetric studies, high interest for therapy. The result of the study shows a favorable kinetics for 188 Re, by their physical and chemical characteristics compared to the other evaluated radionuclides. The compartment proposed study describes the metabolism of 188 Reanti- CD20 through a compartment mammillary model, which by their pharmacokinetic analysis, performed compared to products emitters β -131 I-labeled anti CD20, 177 Luanti- CD20, the γ emitter 99m Tc-Anti-CD20 and α emitter 211 At-Anti-CD20 presented a elimination constant of approximately 0.05 hours

  7. Basic principles and practices of integrated dosimetric passportization of the settlements in Ukraine

    International Nuclear Information System (INIS)

    Lyikhtar'ov, Yi.A.; Kovgan, L.M.; Masyuk, S.V.; Yivanova, O.M.; Chepurnij, M.Yi.; Bojko, Z. N.; Gerasimenko, V.B.

    2015-01-01

    The objective of the review is to demonstrate the results of dosimetric passportization (performed in 1991- 2014) for the settlements of Ukraine which suffered from radioactive contamination caused by the Chornobyl accident. The dosimetric passportization played a key role in the National program on the liquidation of after- math of the Chornobyl accident through all stages of the current radiation situation control and decision support touching upon various types of interventions and social benefits to the population of radioactively contaminated areas. The works being performed under dosimetric passportization did not have analogues among the researches which took place after other large-scale industrial and municipal accidents as well their scales as the duration of both radio-ecological and dosimetric monitoring. The new methodological approaches to the assessment of so-called passport doses of a settlement as well as to the definition of the concept of annual dose being the dose used to make decisions for providing both direct and indirect emergency countermeasures for the settlements of Ukraine became pioneering ones. During all the post-accident period there were issued sixteen collections of general dosimetric passportization data which accumulate the results of hundreds of thousands spectrometric, radiochemical and radiation levels measurements and WBC measurements carried out in 1991-2014. The annual passport doses calculated on the basis of these measurements (including their components) are unique information that quantifies the level and time dynamics of the radiation situation for each of the 2161 settlements of 74 districts in 12 regions during all the post-accident period. Thanks to the works of dosimetric passportization of the settlements of Ukraine there were created databases to be unique in their structure and content with quantitative characteristics of the territorial and temporal distribution, the dynamics of changes of a number of important

  8. 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.

  9. Dosimetric comparison of radionuclides for therapy of somatostatin receptor-expressing tumors

    International Nuclear Information System (INIS)

    Bernhardt, Peter; Benjegaard, Sven Anders; Koelby, Lars; Johanson, Viktor; Nilsson, Ola; Ahlman, Haakan; Forssell-Aronsson, Eva

    2001-01-01

    Purpose: Therapy of tumors expressing somatostatin receptors, sstr, has recently been clinically tested using somatostatin analogues labeled with 111 In and 90 Y. Several other radionuclides, i.e., 131 I, 161 Tb, 64 Cu, 188 Re, 177 Lu, and 67 Ga, have also been proposed for this type of therapy. The aim of this work was to investigate the usefulness of the above-mentioned radionuclides bound to somatostatin analogues for tumor therapy. Methods: Biokinetic data of 111 In-labeled octreotide in mice and man were used, primarily from our studies but sometimes from the literature. Dosimetric calculations were performed with the assumption that biokinetics were similar for all radionuclides bound to somatostatin analogues. The cumulated tumor:normal-tissue activity concentration, TNC∼, was calculated for the various physical half-lives of the radionuclides. Using mathematical models, the tumor:normal-tissue mean absorbed dose rate ratio, TN D, and tumor:normal-tissue mean absorbed dose ratio, TND, were calculated for various tumor sizes in mice and humans. Results: TNC∼ of radionuclide-labeled octreotide increased with physical half-life for most organs, both in mice and in humans. TN D showed that radionuclides emitting electrons with too high energy are not suitable for therapy of small tumors. Furthermore, radionuclides with a higher frequency of photon emissions relative to electron emissions will yield lower TN D and are thus less suitable for therapy than radionuclides with a lower frequency of photon emissions. The TND was highest for 161 Tb in both mice and humans. Conclusions: The results demonstrate that long-lived radionuclides, which emit electrons with rather low energy and which have low frequency of photon emissions, should be the preferred therapy for disseminated small sstr-expressing tumors

  10. The dosimetric impact of implants on the spinal cord dose during stereotactic body radiotherapy

    International Nuclear Information System (INIS)

    Yazici, Gozde; Sari, Sezin Yuce; Yedekci, Fazli Yagiz; Yucekul, Altug; Birgi, Sumerya Duru; Demirkiran, Gokhan; Gultekin, Melis; Hurmuz, Pervin; Yazici, Muharrem; Ozyigit, Gokhan; Cengiz, Mustafa

    2016-01-01

    The effects of spinal implants on dose distribution have been studied for conformal treatment plans. However, the dosimetric impact of spinal implants in stereotactic body radiotherapy (SBRT) treatments has not been studied in spatial orientation. In this study we evaluated the effect of spinal implants placed in sawbone vertebra models implanted as in vivo instrumentations. Four different spinal implant reconstruction techniques were performed using the standard sawbone lumbar vertebrae model; 1. L2-L4 posterior instrumentation without anterior column reconstruction (PI); 2. L2-L4 anterior instrumentation, L3 corpectomy, and anterior column reconstruction with a titanium cage (AIAC); 3. L2-L4 posterior instrumentation, L3 corpectomy, and anterior column reconstruction with a titanium cage (PIAC); 4. L2-L4 anterior instrumentation, L3 corpectomy, and anterior column reconstruction with chest tubes filled with bone cement (AIABc). The target was defined as the spinous process and lamina of the lumbar (L) 3 vertebra. A thermoluminescent dosimeter (TLD, LiF:Mg,Ti) was located on the measurement point anterior to the spinal cord. The prescription dose was 8 Gy and the treatment was administered in a single fraction using a CyberKnife® (Accuray Inc., Sunnyvale, CA, USA). We performed two different treatment plans. In Plan A beam interaction with the rod was not limited. In plan B the rod was considered a structure of avoidance, and interaction between the rod and beam was prevented. TLD measurements were compared with the point dose calculated by the treatment planning system (TPS). In plan A, the difference between TLD measurement and the dose calculated by the TPS was 1.7 %, 2.8 %, and 2.7 % for the sawbone with no implant, PI, and PIAC models, respectively. For the AIAC model the TLD dose was 13.8 % higher than the TPS dose; the difference was 18.6 % for the AIABc model. In plan B for the AIAC and AIABc models, TLD measurement was 2.5 % and 0.9 % higher than the

  11. Thermodynamic quantities and defect equilibrium in La2-xSrxNiO4+δ

    International Nuclear Information System (INIS)

    Nakamura, Takashi; Yashiro, Keiji; Sato, Kazuhisa; Mizusaki, Junichiro

    2009-01-01

    In order to elucidate the relation between thermodynamic quantities, the defect structure, and the defect equilibrium in La 2-x Sr x NiO 4+δ , statistical thermodynamic calculation is carried out and calculated results are compared to those obtained from experimental data. Partial molar enthalpy of oxygen and partial molar entropy of oxygen are obtained from δ-P(O 2 )-T relation by using Gibbs-Helmholtz equation. Statistical thermodynamic model is derived from defect equilibrium models proposed before by authors, localized electron model and delocalized electron model which could well explain the variation of oxygen content of La 2-x Sr x NiO 4+δ . Although assumed defect species and their equilibrium are different, the results of thermodynamic calculation by localized electron model and delocalized electron model show minor difference. Calculated results by the both models agree with the thermodynamic quantities obtained from oxygen nonstoichiometry of La 2-x Sr x NiO 4+δ . - Graphical abstract: In order to elucidate the relation between thermodynamic quantities, the defect structure, and the defect equilibrium in La 2-x Sr x NiO 4+δ , statistics thermodynamic calculation is carried out and calculated results are compared to those obtained from experimental data.

  12. 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)

  13. 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.

  14. 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.

  15. 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.

  16. Study of the Phototransference in GR-200 Dosimetric Material and its Convenience for Dose Re-estimation

    International Nuclear Information System (INIS)

    Baly, L.; Otazo, M. R.; Molina, D.; Pernas, R.

    2006-01-01

    A study of the phototransference of charges from deep to dosimetric traps in GR-200 material is presented and its convenience for dose re-estimation in the dose range between 2 and 100mSv is also analyzed. The recovering coefficient (RC) defined as the ratio between the phototransferred thermoluminescence (PTTL) and the original thermoluminescence (TL) of the dosimetric trap was used to evaluate the ratio of phototransferred charges from deep traps and the original charges in the dosimetric traps. The results show the convenience of this method for dose re-estimation for this material in the selected range of doses

  17. Dosimetric evaluation of whole-breast radiation therapy: Clinical experience

    International Nuclear Information System (INIS)

    Osei, Ernest; Darko, Johnson; Fleck, Andre; White, Jana; Kiciak, Alexander; Redekop, Rachel; Gopaul, Darin

    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 3 (range: 73.6 to 3684.6 cm 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 92% PD ) and 95% (V 95% 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 105% 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 PTV_eval are 0.09 (range: 0.05 to 0

  18. Dosimetric effectiveness in implants with distinct HO166-seed distribution in prostate

    International Nuclear Information System (INIS)

    Braga, Viviane V. B.; Campos, Tarcísio P. R.

    2017-01-01

    Currently, there is a need to produce new therapeutic techniques for the treatment of prostate tumors, considering the high incidence of the disease and significant morbidity rates associated with surgery and radiotherapy. Simulations in brachytherapy produce essential information about the efficiency and dosimetric efficacy compared to other techniques. Computational simulation by Monte Carlo method has been used to evaluate the absorbed dose and effective dose in radiotherapy and radiology. Virtual, analytical or voxelized phantoms are useful in the internal assessment of the spatial distribution of absorbed dose. This study estimated the efficiency of dosimetry by parameters of merit generated from volumetric distributions of absorbed doses simulating various spatial distributions of Ho-166 seeds in a prostate model. A computer model of voxels was developed, using the code SISCODES (Computational System for Dosimetry by Neutrons and Photons by Stochastic Methods applied to radiology and radiotherapy), representative of a real physical simulator predefined as a calibration method. The virtual model reproduced a cubic box, filled with muscle equivalent tissue (TE), where a 5-cm diameter ball with TE-prostate was positioned 2-cm from the air interface. A Ho-166 seed distribution, produced by 16 filet-implants distributed regularly (10-mm pitch) containing 04 separate 8-mm seeds, was employed. Two pitch were considered: 9 and 10 mm, with same distance between seed in a fillet. Based on SISCODE database of chemical composition of tissues and nuclear data, The code allowed the association of nuclear and chemical data to the voxels of the model, by the selection of the tissue of each voxel, as well as the positioning of the sources and their spatial distribution and spectra. The code MCNP5 simulated the transport of photons and electrons in the model, generating the energy deposited per unit mass in each voxel for photons in MeV.g-1 and energy absorbed in MeV for beta

  19. Dosimetric effectiveness in implants with distinct HO166-seed distribution in prostate

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Viviane V. B.; Campos, Tarcísio P. R., E-mail: Vitoriabraga06@gmail.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    Currently, there is a need to produce new therapeutic techniques for the treatment of prostate tumors, considering the high incidence of the disease and significant morbidity rates associated with surgery and radiotherapy. Simulations in brachytherapy produce essential information about the efficiency and dosimetric efficacy compared to other techniques. Computational simulation by Monte Carlo method has been used to evaluate the absorbed dose and effective dose in radiotherapy and radiology. Virtual, analytical or voxelized phantoms are useful in the internal assessment of the spatial distribution of absorbed dose. This study estimated the efficiency of dosimetry by parameters of merit generated from volumetric distributions of absorbed doses simulating various spatial distributions of Ho-166 seeds in a prostate model. A computer model of voxels was developed, using the code SISCODES (Computational System for Dosimetry by Neutrons and Photons by Stochastic Methods applied to radiology and radiotherapy), representative of a real physical simulator predefined as a calibration method. The virtual model reproduced a cubic box, filled with muscle equivalent tissue (TE), where a 5-cm diameter ball with TE-prostate was positioned 2-cm from the air interface. A Ho-166 seed distribution, produced by 16 filet-implants distributed regularly (10-mm pitch) containing 04 separate 8-mm seeds, was employed. Two pitch were considered: 9 and 10 mm, with same distance between seed in a fillet. Based on SISCODE database of chemical composition of tissues and nuclear data, The code allowed the association of nuclear and chemical data to the voxels of the model, by the selection of the tissue of each voxel, as well as the positioning of the sources and their spatial distribution and spectra. The code MCNP5 simulated the transport of photons and electrons in the model, generating the energy deposited per unit mass in each voxel for photons in MeV.g-1 and energy absorbed in MeV for beta

  20. 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.

  1. 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

  2. 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.

  3. Dosimetric Evaluation of VMAT, IMRT, and Proton Treatment Techniques Targeting Borderline Resectable Pancreatic Cancer Lesions

    Science.gov (United States)

    Harpool, Kristyn Brenna

    Purpose: With the advent of Volumetric Modulated Arc Therapy (VMAT), clinicians opted to favor this technology assuming it a better form of treatment. It was of interest to investigate its benefits compared to Intensity Modulated Radiation Therapy (IMRT) when creating treatment plans for pancreatic cancer for which challenges are considered: target location, avoiding excess dose to surrounding organs, and keeping highest dose within the planned target volume. This study aimed to determine which technique offered the best dose conformity and healthy organ sparing based on dosimetry and radiobiology models to help the clinic distribute fairly the patient load to the most adequate treatment delivery machine. Materials and Methods: Twenty pancreatic cancer treatment plans were analyzed. Original plans were re-planned and calculated with Varian Eclipse treatment planning system using VMAT or IMRT to create paired data sets. IMRT plans utilized 6-9 fields and VMAT plans used two arc fields. Both techniques used 6 MV beams and prescription dose of 4950 cGy in 18 fractions. Plan evaluations were based on Conformity Index (CI) and normal tissue (kidneys, liver, spinal cord, and bowel) doses analyzed using QUANTEC; and radiobiology analysis using the Uncomplicated Tumor Control Probability (UTCP). Results: On average, VMAT resulted in 10.56% (p = 0.19) and 17.46% (p = 0.16) higher mean doses to the total kidneys and liver and 7.48% (p = 0.10) and 0.44% (p = 0.93) lower mean doses to the bowel and maximum spinal cord dose, respectively. Conclusions: VMAT has not shown to be a significantly superior technique at providing target coverage and sparing normal structures, thus determination of the treatment technique should be based on individual cases. Purpose: To examine dosimetric differences between AAA and Acuros XB mathematical treatment planning software in the treatment of pancreatic cancer. Materials and Methods: CT images from twelve pancreatic cancer patients were used

  4. Quantities of natural gas transported in August-December 2007

    International Nuclear Information System (INIS)

    2008-01-01

    GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the available monthly key figures of GRTgaz activity from August to December 2007: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

  5. Quantities of natural gas transported in January-December 2009

    International Nuclear Information System (INIS)

    2010-01-01

    GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the monthly key figures of GRTgaz activity in 2009: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

  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. 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 spatialthinking and number sense. Narrowing for this small research, we focused onone component of spatial thinking, that is structuring objects, and onecomponent of number senses, that is cardinality by determining quantities. Thisstudy focused on a design research that was conducted in Indonesia in which weinvestigated pre-school children’s (between 2 and 3.5 years old ability inmaking structured arrangement and their ability to determine the quantities bylooking at the arrangements. The result shows us that some of the children wereable to make such arrangement. However, the children found difficulties eitherto determine quantities from those arrangements or to compare some structuresto easily recognize number of objects.Keywords: structures, structured arrangement, cardinality DOI: http://dx.doi.org/10.22342/jme.1.1.790.53-70

  8. Quantities of natural gas transported in January-December 2008

    International Nuclear Information System (INIS)

    2009-01-01

    GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the monthly key figures of GRTgaz activity in 2008: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

  9. Dosimetric impact of interfraction catheter movement and organ motion on MRI/CT guided HDR interstitial brachytherapy for gynecologic cancer

    International Nuclear Information System (INIS)

    Rey, Felipe; Chang, Chang; Mesina, Carmen; Dixit, Nayha; Kevin Teo, Boon-Keng; Lin, Lilie L.

    2013-01-01

    Purpose: To determine the dosimetric impact of catheter movement for MRI/CT image guided high dose rate (HDR) interstitial brachytherapy (ISBT) for gynecologic cancers. Materials and methods: Ten patients were treated with HDR ISBT. The CTV and organs at risk were contoured using a postimplant MRI and CT. 5 fractions were delivered twice daily on 3 consecutive days. The first fraction was delivered on day 1 (d1), fraction 2–3 on d2 and fraction 4–5 on d3. MRI/CT was acquired prior to the second and fourth fractions. Four scenarios were modeled. (1) The d1 plan was applied to the d2 and d3 CT, using the updated catheter positions. (2) Replanning was performed for d2 and d3. (3) We applied the dwell positions/times from the d2 replan over the d3 CT and compared with a d3 CT replan. (4) Based on daily MRI, target volumes were recontoured and replanned. Dosimetry was analyzed for each plan and compared to the d1 dose distribution. Results: (1) When using the d1 plan on the d2 and d3 CT with the updated catheter positions, the mean CTV D90 was reduced from 93.4% on d1 to 89.3% (p = 0.08) on d2 and to 87.7% (p = 0.005) on d3. (2) Replanning on d2 and d3 compensated for catheter movement, mean CTV D90 of 95.4% on d2 and 94.6% (p = 0.36) on d3. (3) When compared to the replan of d2 applied on the d3 CT vs the d3 replan, there was no significant difference in coverage, mean CTV D90 of 90.9% (p = 0.09). (4) Reoptimization based on daily MRI, significantly improved the CTV coverage for each day. The mean D2 cc for the rectum was significantly higher with model 1 vs model 3 59.1 ± 4.7 vs 60.9 ± 4.8 (p = 0.04) Gy EQD2. There were no significant differences in D2 cc of bladder and sigmoid between models. Conclusions: Interfraction dosimetric changes significantly decreased the CTV coverage of the third day. Rather than replanning on each day, replanning on the day 2 CT before the second or third fraction would give an optimal solution that would compensate for

  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 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

  12. Foreign materials in the repository. Update of estimated quantities

    International Nuclear Information System (INIS)

    Karvonen, T.

    2011-06-01

    A variety of materials are used during the construction process and the operation of the repository for spent nuclear fuel at Olkiluoto in Eurajoki, Finland. In addition to materials necessary for the construction and operation, some materials may be transported into the repository with the ventilation air, as emissions from vehicles etc. Both of these two types of materials are considered here and both introduced quantities and the quantities that remain after the closure in the repository are estimated here based on the most recent information. This work is intended to update the previous estimations, and it takes advantage of the experience collected during the construction of the underground rock characterisation facility called ONKALO at Olkiluoto. The implemented quantities as well as designs and preliminary designs have been used in calculating the quantities of the foreign materials. The estimations made in this report are specific to a KBS-3V type repository. In some cases more generic information has been used, particularly when the relevant quantities have not been monitored in ONKALO. The estimations are based on the new repository layout produced in 2010 and consider the latest plans for grouting and rock support. As all of these plans are not final some quantities may change in the future. As the repository layout may still go through some changes this report also provides the foreign materials for a hundred meters of different deposition tunnels designed for the OL and LO type canisters1. The results have also been calculated for a space demanded by a deposition tunnel end plug and the tunnel lengths before and after one. The most significant foreign materials are certain accessory minerals of the clay materials followed by organic materials (including the organic carbon from the clay materials), cement, steel and silica. (orig.)

  13. 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

  14. Dosimetric properties of a proton beamline dedicated to the treatment of ocular disease

    International Nuclear Information System (INIS)

    Slopsema, R. L.; Mamalui, M.; Yeung, D.; Malyapa, R.; Li, Z.; Zhao, T.

    2014-01-01

    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 2 ; the modulation width can be varied in steps of 0.3 g/cm 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 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 on range (up

  15. 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

  16. Dosimetric impact of an accident in a laboratory treating irradiated fuels. Analysis of the doses sensitivity to the fuel characteristics

    International Nuclear Information System (INIS)

    Vermuse, M.

    1997-01-01

    The objective of this study is to determine the sensitivity of dosimetric impact of a dimensioning accident to the characteristics (combustion rate, cooling time, enrichment) of spent fuels treated in the facility. The study has to allow to define the most penalizing characteristics of the fuel in regard of dosimetric consequences during a dimensioning accident and to display the most preponderant radionuclides for the considered ways of attack. (N.C.)

  17. Quantities of natural gas transported in January-December 2010. Quantities of natural gas transmitted in January-December 2010

    International Nuclear Information System (INIS)

    2011-01-01

    GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the monthly key figures of GRTgaz activity in 2010: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

  18. Quantities of natural gas transmitted in January-December 2012. Quantities of natural gas transported in January-December 2012

    International Nuclear Information System (INIS)

    2013-01-01

    GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the monthly key figures of GRTgaz activity in 2012: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

  19. Quantities of natural gas transmitted in January-December 2011. Quantities of natural gas transported in January-December 2011

    International Nuclear Information System (INIS)

    2012-01-01

    GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents the monthly key figures of GRTgaz activity in 2011: Total quantities transmitted by GRTgaz (Inputs to the GRTgaz network/Outputs from the GRTgaz network); Maximum and minimum daily flow (Daily quantities transported, Daily consumption, Daily inputs excluding storage); Quantities exchanged on the wholesale market; Consumption on the GRTgaz Network (gross monthly consumption and Average monthly temperatures)

  20. Dosimetric study in fluoroscopy procedures realized on Recife, PE, Brazil

    International Nuclear Information System (INIS)

    Maia, Ana Figueiredo

    2001-08-01

    Fluoroscopy is a special radiological examination that uses radiation to visualize the image directly in a TV monitor. Due to of the large exposure times, these procedures often give high doses to the patient, usually higher than those from conventional radiology. Since there are not international diagnostic references levels for fluoroscopy procedures, this research had the objective of making the first study of the fluoroscopy procedures in the Northeast Region of Brazil, providing, therefore, data for the implementation of diagnostic reference levels. Three institutions were evaluated in Recife, two of them teaching hospitals. The quantities measured were the air kerma-area-product, the screening time and the number of radiographs taken in each exam. The results show that the value of the air kerma-area-product varied among the institutions and the results in the institution which uses the last generation equipment were better than those obtained in the other institutions. A relevant fact, and also alarming, is that the population in the institutions that showed the worse results are children. The results obtained in these institutions are higher than those observed in other countries. The results of this research show that there is a need for optimization in those procedures, specially the ones that involve older equipment. It is also points to the continuity of this study to gather more information to define the fluoroscopy reference levels in the country. (author)

  1. Resource rents: The effects of energy taxes and quantity instruments for climate protection

    International Nuclear Information System (INIS)

    Eisenack, Klaus; Edenhofer, Ottmar; Kalkuhl, Matthias

    2012-01-01

    Carbon dioxide emissions correspond to fossil resource use. When considering this supply side of climate protection, crucial questions come to fore. It seems likely that owners of fossil resources would object to emission reductions. Moreover, policy instruments such as taxes may not be effective at all: it seems individually rational to leave no fossil resources unused. In this context, it can be expected that economic sectors will react strategically to climate policy, aiming at a re-distribution of rents. To address these questions, we investigate the effectiveness, efficiency, and resource rents for energy taxes, resource taxes, and quantity rationing of emissions. The analysis is 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 quantity rationing achieve this objective efficiently, energy taxation is only second-best. The use of quantity rationing to achieve climate protection generates substantial rents for resource owners. - Highlights: ► Resource taxes and quantity rationing (carbon budgets) are efficient. ► Carbon budgets increase resource rents, while taxes decrease rents. ► Resource owners may support climate protection. ► Climate protection introduces a climate rent.

  2. On the evaluation of Hardy's thermomechanical quantities using ensemble and time averaging

    International Nuclear Information System (INIS)

    Fu, Yao; To, Albert C

    2013-01-01

    An ensemble averaging approach was investigated for its accuracy and convergence against time averaging in computing continuum quantities such as stress, heat flux and temperature from atomistic scale quantities. For this purpose, ensemble averaging and time averaging were applied to evaluate Hardy's thermomechanical expressions (Hardy 1982 J. Chem. Phys. 76 622–8) in equilibrium conditions at two different temperatures as well as a nonequilibrium process due to shock impact on a Ni crystal modeled using molecular dynamics simulations. It was found that under equilibrium conditions, time averaging requires selection of a time interval larger than the critical time interval to obtain convergence, where the critical time interval can be estimated using the elastic properties of the material. The reason for this is because of the significant correlations among the computed thermomechanical quantities at different time instants employed in computing their time average. On the other hand, the computed thermomechanical quantities from different realizations in ensemble averaging are statistically independent, and thus convergence is always guaranteed. The computed stress, heat flux and temperature show noticeable difference in their convergence behavior while their confidence intervals increase with temperature. Contrary to equilibrium settings, time averaging is not equivalent to ensemble averaging in the case of shock wave propagation. Time averaging was shown to have poor performance in computing various thermomechanical fields by either oversmoothing the fields or failing to remove noise. (paper)

  3. 7 CFR 983.53 - Testing of minimal quantities.

    Science.gov (United States)

    2010-01-01

    ... Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE PISTACHIOS GROWN IN CALIFORNIA, ARIZONA, AND NEW MEXICO Regulations § 983.53 Testing of minimal quantities. (a) Aflatoxin. Handlers who... following methods for testing for aflatoxin: (1) The handler may have an inspector sample and test his or...

  4. Photographs in Dutch History Textbooks: Quantity, type and educational use

    NARCIS (Netherlands)

    M. Kleppe (Martijn)

    2010-01-01

    textabstractThis article demonstrates a media scientific approach by studying the use of photographs in Dutch History textbooks for High School pupils in the period 1970 – 2000. The quantity of photos has been determined as well as the types of pictures and its use as educational tool. Results show

  5. Investigation of potential water quality and quantity impacts ...

    African Journals Online (AJOL)

    A scoping level study was performed to consolidate the existing information on the geohydrology and pre-mining water quantity and quality of water resources associated with the Waterberg coal reserves. New data regarding water quality and acid-base potential for the different geological areas (through field investigations) ...

  6. Hazardous Waste Management for the Small Quantity Generator. Teacher Edition.

    Science.gov (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This instructional package for teaching about the regulations imposed on small quantity generators by the Environmental Protection Agency (EPA) under the Resource Conservation Recovery Act is organized around ll program objectives: students will be able to (l) determine a hazardous waste from lists or by identifying characteristics; (2) identify…

  7. Birthday Cake Activity Structured Arrangement for Helping Children Determining Quantities

    Science.gov (United States)

    Mariana, Neni

    2010-01-01

    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…

  8. 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,…

  9. Teacher quality and quantity as correlates of secondary school ...

    African Journals Online (AJOL)

    This study investigated the twin variables of quality and quantity of teachers as correlates of secondary school academic performance in Ogun State of Nigeria between 1997/98 and 2000/2001 academic sessions. The study was conducted ex-post facto under a descriptive survey research design using the proportional to ...

  10. Food quantity affects the sensitivity of Daphnia to road salt.

    Science.gov (United States)

    Brown, Arran H; Yan, Norman D

    2015-04-07

    Road deicing operations have raised chloride (Cl) levels in many temperate lakes in Europe and North America. These lakes vary widely in trophic status, but to date, no one has quantified the interaction between food quantity and road salt toxicity. We examined the effects of food quantity (particulate algal C concentration (C)) on the chronic toxicity of Cl to Daphnia in soft-water bioassays. There was a strong positive linear relationship (r(2) = 0.92 for NaCl and r(2) = 0.96 for CaCl2) between food quantity and Cl LC50. As food quantity increased from 0.2 to 1.0 mg C/L (levels characteristic of oligotrophic to eutrophic lakes, respectively), the chronic Cl LC50 increased from 55.7 to 284.8 mg Cl/L. Salt type (NaCl or CaCl2) did not affect the Cl LC50, Daphnia life history parameters, or the intrinsic rate of population increase (r). The life history parameter most sensitive to Cl was neonate production. Cl did not inhibit egg production, nor was the maternal lipid investment in eggs changed, but egg viability and the subsequent release of live neonates decreased as Cl levels increased and food decreased. Our results suggest the trophic status of lakes should be considered when assessing ecological threat from Cl.

  11. Can the Lorenz-Gauge Potentials Be Considered Physical Quantities?

    Science.gov (United States)

    Heras, Jose A.; Fernandez-Anaya, Guillermo

    2010-01-01

    Two results support the idea that the scalar and vector potentials in the Lorenz gauge can be considered to be physical quantities: (i) they separately satisfy the properties of causality and propagation at the speed of light and do not imply spurious terms and (ii) they can naturally be written in a manifestly covariant form. In this paper we…

  12. Discrimination of small quantities by fish (redtail splitfin, Xenotoca eiseni).

    Science.gov (United States)

    Stancher, Gionata; Sovrano, Valeria Anna; Potrich, Davide; Vallortigara, Giorgio

    2013-03-01

    Discrimination of quantity has been argued to rely on two non-verbal representational systems: an object file system (OFS) for representing small values (≤3-4) and an analog magnitude system (AMS) for representing large magnitudes (>4). Infants' ability to discriminate 1 versus 2, 1 versus 3, 2 versus 3, but not 1 versus 4 or 2 versus 4 seems to prove the independence of such systems. Here, we show that redtail splitfin fish (Xenotoca eiseni) performed relative quantity estimations preferring to approach the location previously occupied by the larger in number between two groups of conspecifics (no longer visible at test) in sets of 1 versus 2 and 2 versus 3 items, but failed at 3 versus 4 items, thus showing the same set-size limit as infants for discrimination of small quantities. However, when tested with quantities that spanned the boundary of the two systems, that is, 1 versus 4 and 2 versus 4, fish succeeded. These results thus point to either the use of continuous physical variables and/or the use of the AMS also for small numerousness in fish in this task.

  13. English Syllabic Consonants and Quantity Factor in Educated ...

    African Journals Online (AJOL)

    This study aimed at investigating the duration and quantity in the realization of the unstressed syllables that have syllabic consonants as peaks in Educated Yoruba English (EYE), a sub-variety of Nigerian English. Three hundred Yoruba speakers of English with not lower than Ordinary National Diploma (OND) and Nigeria ...

  14. Mapping among Number Words, Numerals, and Nonsymbolic Quantities in Preschoolers

    Science.gov (United States)

    Hurst, Michelle; Anderson, Ursula; Cordes, Sara

    2017-01-01

    In mathematically literate societies, numerical information is represented in 3 distinct codes: a verbal code (i.e., number words); a digital, symbolic code (e.g., Arabic numerals); and an analogical code (i.e., quantities; Dehaene, 1992). To communicate effectively using these numerical codes, our understanding of number must involve an…

  15. Determining spatial and temporal variability in quantity and quality of ...

    African Journals Online (AJOL)

    This study assessed the importance of spatial and temporal variation in plant quality and quantity for determining sustainable stocking rates in game, commercial and communal ranches in semi-arid savanna ... Habitat type had greater effects on plant quality, plant biomass and species composition than management type.

  16. Water quantity and quality at the urban-rural interface

    Science.gov (United States)

    Ge Sun; B. Graeme Lockaby

    2012-01-01

    Population growth and urban development dramatically alter natural watershed ecosystem structure and functions and stress water resources. We review studies on the impacts of urbanization on hydrologic and biogeochemical processes underlying stream water quantity and water quality issues, as well as water supply challenges in an urban environment. We conclude that...

  17. Quantity and quality of written feedback, action plans, and student ...

    African Journals Online (AJOL)

    Background. Mini-clinical-evaluation exercise (mini-CEX) assessment forms that have been modified with the addition of specific spaces on separate sheets are expected to improve the quantity and quality of written feedback and the action plan for further learning which is agreed upon, and to encourage written reflection.

  18. Determination of optimal quantities of different types of driers for ...

    African Journals Online (AJOL)

    user

    The Paint Manufacturing Process and the Problem. The flow chart of the paint manufacturing process is shown in Figure 1. The required quantities of binders, pigments, fillers and additives (except driers) for a batch are fed into the feed hopper. These materials are then transferred to the mixing machine where the input ...

  19. 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.,…

  20. Application of optimisation techniques in groundwater quantity and ...

    Indian Academy of Sciences (India)

    Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45

    the solution of groundwater quantity and quality management problems. The combined use of simulation and optimisation techniques have been demonstrated to be powerful and useful methods in determining planning and management strategies for optimal development and operation of groundwater systems. Simulation ...

  1. 30 CFR 75.322 - Harmful quantities of noxious gases.

    Science.gov (United States)

    2010-07-01

    ... Section 75.322 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.322 Harmful quantities of noxious gases. Concentrations of noxious or poisonous gases, other than carbon dioxide, shall...

  2. Whither the Nigerian Quantity Surveyors in the Information ...

    African Journals Online (AJOL)

    The paucity of information on the computing status of the quantity surveyors in Nigeria have been scanty and without empirical substantiation. The basic platform for entry to the information technology gateway is the acquisition, adoption and utilization of the computer. Baseline information is therefore indispensable for the ...

  3. 19 CFR 351.409 - Differences in quantities.

    Science.gov (United States)

    2010-04-01

    ... DUTIES Calculation of Export Price, Constructed Export Price, Fair Value, and Normal Value § 351.409... comparing export price or constructed export price with normal value, the Secretary will make a reasonable... section 773(a)(6)(C)(i) of the Act.) (b) Sales with quantity discounts in calculating normal value. The...

  4. Using break quantities for tactical optimisation in multistage distribution systems

    NARCIS (Netherlands)

    M.J. Kleijn (Marcel); R. Dekker (Rommert)

    1997-01-01

    textabstractIn this chapter we discuss a tactical optimisation problem that arises in a multistage distribution system where customer orders can be delivered from any stockpoint. A simple rule to allocate orders to locations is a break quantity rule, which routes large orders to higher-stage

  5. Thermodynamic quantities for the Klein–Gordon equation with a ...

    Indian Academy of Sciences (India)

    We study some thermodynamic quantities for the Klein–Gordon equation with a linear plus inverselinear, scalar potential. We obtain the energy eigenvalues with the help of the quantization rule from the biconfluent Heun's equation.We use a method based on the Euler–MacLaurin formula to analytically compute thethermal ...

  6. Perceptions of Brainstorming in Groups: The Quality over Quantity Hypothesis.

    Science.gov (United States)

    Rowatt, Wade C.; And Others

    1997-01-01

    Four studies of undergraduates were conducted to assess the relative importance of quality and quantity as goals of brainstorming. Participants (n=65) believed it was more important to produce creative and high-quality ideas than to generate many ideas and believed brainstorming would enhance the quality of others' ideas (n=109). (Author/CR)

  7. Thermodynamic quantities for the Klein–Gordon equation

    Indian Academy of Sciences (India)

    We study some thermodynamic quantities for the Klein–Gordon equation with a linear plus inverselinear, scalar potential. We obtain the energy eigenvalues with the help of the quantization rule from the biconfluent Heun's equation.We use a method based on the Euler–MacLaurin formula to analytically compute thethermal ...

  8. Thermodynamic quantities for the Klein–Gordon equation with a ...

    Indian Academy of Sciences (India)

    2017-02-01

    Feb 1, 2017 ... Abstract. We study some thermodynamic quantities for the Klein–Gordon equation with a linear plus inverse- linear, scalar potential. We obtain the energy eigenvalues with the help of the quantization rule from the biconfluent Heun's equation. We use a method based on the Euler–MacLaurin formula to ...

  9. Is the dose equivalent index a quantity to be measured

    International Nuclear Information System (INIS)

    Wagner, S.R.

    1980-01-01

    The following modifying factors are briefly considered in relation to the ambiguities and limitations of the Dose Equivalent Index: 1) Variations with time or of the movement of the exposed person 2) Irradiation geometry 3) Effect of radiation energy 4) Instrument performance and calibration, and other operational quantities. (U.K.)

  10. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    International Nuclear Information System (INIS)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade

    2009-01-01

    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)

  11. 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)

  12. Dosimetric systems developed in Brazil for the radiation processes quality control

    International Nuclear Information System (INIS)

    Galante, Ana Maria Sisti; Campos, Leticia Lucente

    2011-01-01

    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).

  13. Development and application of a dosimetric methodology of therapeutic X radiation beams using a tandem system

    International Nuclear Information System (INIS)

    Sartoris, Carla Eri

    2001-01-01

    In radiotherapy the use of orthovoltage X radiation beams is still recommended; to obtain satisfactory results, a periodic control is necessary to check the performance of the ionization chambers and the radiation beams characteristics. This control is performed by using standard dosimetric procedures, as for example the determination of half-value layers and the absorbed dose rates. A Tandem system was established in this work using a pair of ionization chambers (a thimble type and a superficial type) used for measures in a medical institution, in substitution to the routine conventional procedure of determination of half-value layers using absorbers. The results obtained show the application of this method in dosimetric procedures of orthovoltage beams (radiotherapy) as a complement for a quality control program. (author)

  14. 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).

  15. Ten years of a National Service of Dosimetric calibration at radiation protection

    International Nuclear Information System (INIS)

    Morales, J.A.; Jova, L.; Hernandez, E.; Campa, R.; Walwyn, G.

    1996-01-01

    Since 1986, the CPHR has offered a national service of calibration of dosimetric instruments at levels of radiation protection. The history of such a service is the chronology of efforts to reduce the uncertainties of the calibration process, expand the ranges of useful dose rates, and enhance the radiological safety when using the sources. The crowning of those efforts is the complement and start-up of the secondary la laboratory of dosimetric calibration (SLDC), which is currently a member of the IAEA/WHO. SLDC international network. As a result of this service, 256 instruments have been calibration and 867 personal dosimeters film badges and TLD and 72 environmental TLD dosimeters have been irradiated at known doses. The service rendered has benefited 62 national institutions which are users of ionizing radiations

  16. Biokinetics and dosimetric studies about 99mTc(V)DMSA distribution

    International Nuclear Information System (INIS)

    Correia, M.B.L.; Magnata, S.S.L.P.; Silva, I.M.S.; Lima, F.F.; Catanho, M.T.J.A.

    2008-01-01

    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 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 99m Tc(V)-DMSA by animal model. The 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 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 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

  17. Verification criteria on the reliability of personal dosimetric services from x and gamma radiations

    International Nuclear Information System (INIS)

    Borasi, G.; Benco, A.; Kaftal, S.

    1990-07-01

    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. (author)

  18. Dosimetric Considerations in Respiratory-Gated Deep Inspiration Breath-Hold for Left Breast Irradiation.

    Science.gov (United States)

    Walston, Steve; Quick, Allison M; Kuhn, Karla; Rong, Yi

    2017-02-01

    To present our clinical workflow of incorporating AlignRT for left breast deep inspiration breath-hold treatments and the dosimetric considerations with the deep inspiration breath-hold protocol. Patients with stage I to III left-sided breast cancer who underwent lumpectomy or mastectomy were considered candidates for deep inspiration breath-hold technique for their external beam radiation therapy. Treatment plans were created on both free-breathing and deep inspiration breath-hold computed tomography for each patient to determine whether deep inspiration breath-hold was beneficial based on dosimetric comparison. The AlignRT system was used for patient setup and monitoring. Dosimetric measurements and their correlation with chest wall excursion and increase in left lung volume were studied for free-breathing and deep inspiration breath-hold plans. Deep inspiration breath-hold plans had significantly increased chest wall excursion when compared with free breathing. This change in geometry resulted in reduced mean and maximum heart dose but did not impact lung V 20 or mean dose. The correlation between chest wall excursion and absolute reduction in heart or lung dose was found to be nonsignificant, but correlation between left lung volume and heart dose showed a linear association. It was also identified that higher levels of chest wall excursion may paradoxically increase heart or lung dose. Reduction in heart dose can be achieved for many left-sided breast and chest wall patients using deep inspiration breath-hold. Chest wall excursion as well as left lung volume did not correlate with reduction in heart dose, and it remains to be determined what metric will provide the most optimal and reliable dosimetric advantage.

  19. 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...... of individual monitoring using personal dosemeters and assisting movement towards harmonised procedures. An outline of the work of the action group is given and the term 'harmonisation' is discussed....

  20. [Dosimetric impact of breath-hold in the treatment of hepatocellular carcinoma by conformal radiation therapy].

    Science.gov (United States)

    Kubas, A; Chapet, O; Merle, P; Lorchel, F; d'Hombres, A; Mornex, F

    2009-01-01

    To evaluate the dosimetric impact of breath-hold during radiotherapy of hepatocellular carcinoma (HCC) and to determinate the optimal respiratory phase for treatment (exhale or inhale). Two CT scans were performed in inhale and in exhale in 20 patients with HCC. The GTV was delineated slice by slice on the inspiration breath hold acquisition (GTV(insp)) and on the expiration breath hold acquisition (GTV(exp)). The superposition of two GTV allowed to obtain the global GTV (free respiration). PTV was defined by adding a margin of 1cm around each GTV. The liver, the duodenum, the two kidneys, the stomach and the spinal cord were delineated on each acquisition as organs at risk (OAR). Three dosimetric plans were created on inspiration, expiration and on global PTV. The mean reduction in the volume of PTV with conformal radiation therapy (3D-CRT) in the hold-breath group compared to the free respiration group was of 33.5+/-11.9%. The average difference of V50%, V20, V30, V40 and V50 were around 4% in favor of the breath hold. The average value of NTCP was 8.9% in free respiration, 4.5% in expiration and 3.2% in inspiration. Further improvement in the OARs dosimetric parameters for the breath hold was observed. Compared to the conformal radiotherapy with free respiration, the breath-hold allows reducing the volume of the PTV and the doses to the healthy liver and organs at risk. The use of this modality during different radiotherapy techniques (3D-CRT, IMRT and stereotactic) may be recommended. No difference in dosimetric value has been observed between the breath hold in expiratory and inspiratory phases.