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Sample records for models dosimetric quantities

  1. Discussion on concepts for radiological dosimetric quantities in the Japan Health Physics Society

    International Nuclear Information System (INIS)

    Takahashi, Fumiaki; Oda, Keiji

    2007-01-01

    Many dosimetric quantities have been used for radiation protection purpose. The International Commission on Radiological Protection (ICRP) has recommended protection quantities and the International Commission on Radiation Units and Measurements (ICRU) has introduced operational quantities to provide a reasonable estimate of the protection quantities. Enthusiastic discussions are continuously made on the issues of the dosimetric quantities, such as basic biological data for the definition of these quantities and applicability of the quantities to actual radiation protection practice. At the moment, some changes are being proposed concerning dosimetric quantities in the draft recommendations of ICRP, opened for consultation in recent years. Thus, the Japan Health Physics Society (JHPS) established the Expert Committee on concepts of Dosimetric Quantities used in radiological protection (ECDQ) in April 2005 to reviewed and discuss issues in the dosimetric quantities. (author)

  2. 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)

  3. 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

  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 radiation protection quantities. Impact of the forthcoming ICRP recommendations

    International Nuclear Information System (INIS)

    Pradhan, A.S.; Lee, J.I.; Kim, J.L.; Kim, B.H.

    2008-01-01

    The physical quantities namely fluence, kerma and absorbed dose provide the base for the operational and the protection quantities. The absorbed dose continues to be the fundamental physical quantity for the radiological protection. The most striking feature relating the quantities in the forthcoming recommendations is the updating of the radiation and tissue weighting factors based on the latest available scientific information on radiobiology and the physics of radiation exposure. This is bound to make a significant impact in arriving at the equivalent doses and effective dose. For external exposures of neutrons, the forthcoming recommendations are going to improve the relationship between the operational and protection quantities. The changes in the tissue weighting factors of some tissues/organs, the inclusion of several new tissues/organs for the consideration of tissue weighting factors and the use of the proposed Reference Male and Reference Female voxel phantoms would require new conversion coefficients and dose coefficients for external and internal exposures. The other striking feature appears to be the details of the concepts to ensure that the protections quantities are used for the appropriate and intended purposes only and the misuse is avoided. (author)

  6. 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

  7. 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)

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

    OpenAIRE

    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 exposu...

  9. Mevatron-74 10MeV photon beam: a study of dosimetric quantities

    International Nuclear Information System (INIS)

    Souza, C.N. de

    1986-01-01

    The Mevatron-74 linear accelerator dosimetric quantities were studied. In water and polystyrene measurements with an ionization chamber were done for following physical parameters: maximum dose depth and surface dose, field size dependence, central axis percentage depth dose, beam flatness and simmetry, and also verification the inverse square law for the distances normally used in therapy. Isodose curves were generated by the decrement lines method. (Author) [pt

  10. 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

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

    Directory of Open Access Journals (Sweden)

    Dimitris J Panagopoulos

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

  12. 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

    To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. 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. 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. 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 the biological effect due to non-linearity.

  13. 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)

  14. 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.

  15. 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)

  16. 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

  17. 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

  18. 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

  19. 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)

  20. Dosimetric precision requirements and quantities for characterizing the response of tumors and normal tissues

    Energy Technology Data Exchange (ETDEWEB)

    Brahme, A [Karolinska Inst., Stockholm (Sweden). Dept. of Radiation Physics

    1996-08-01

    Based on simple radiobiological models the effect of the distribution of absorbed dose in therapy beams on the radiation response of tumor and normal tissue volumes are investigated. Under the assumption that the dose variation in the treated volume is small it is shown that the response of the tissue to radiation is determined mainly by the mean dose to the tumor or normal tissue volume in question. Quantitative expressions are also given for the increased probability of normal tissue complications and the decreased probability of tumor control as a function of increasing dose variations around the mean dose level to these tissues. When the dose variations are large the minimum tumor dose (to cm{sup 3} size volumes) will generally be better related to tumor control and the highest dose to significant portions of normal tissue correlates best to complications. In order not to lose more than one out of 20 curable patients (95% of highest possible treatment outcome) the required accuracy in the dose distribution delivered to the target volume should be 2.5% (1{sigma}) for a mean dose response gradient {gamma} in the range 2 - 3. For more steeply responding tumors and normal tissues even stricter requirements may be desirable. (author). 15 refs, 6 figs.

  1. Measuring instruments of the Physikalisch-Technische Bundesanstalt for realization of the units of the dosimetric quantities standard ion dose, photon-equivalent dose and air-kerma

    International Nuclear Information System (INIS)

    Engelke, B.A.; Oetzmann, W.; Struppek, G.

    1988-08-01

    The realization of the units of the dosimetric quantities exposure, air-kerma and photon-equivalent dose is an important task of the Physikalisch-Technische Bundesanstalt. The report describes the measuring instruments and other technical equipment as well as the determination of the numerous corrections needed. All data and correction factors required for the realization of the units mentioned above are given in many diagrams and tables. (orig.) [de

  2. 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

  3. 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

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

    International Nuclear Information System (INIS)

    Weber, D.A.

    1990-01-01

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

  5. Speciation and internal dosimetry: from chemical species to dosimetric models

    International Nuclear Information System (INIS)

    Paquet, F.; Frelon, S.; Cote, G.; Madic, C.

    2004-01-01

    Speciation studies refer to the distribution of species in a particular sample or matrix. These studies are necessary to improve the description, understanding and prediction of trace element kinetics and toxicity. In case of internal contamination with radionuclides, speciation studies could help to improve both the biokinetic and dosimetric models for radionuclides. There are different methods to approach the speciation of radionuclide in a biological system, depending on the degree of accuracy needed and the level of uncertainties accepted. Among them, computer modelling and experimental determination are complementary approaches. This paper describes what is known about speciation of actinides in blood, GI-tract, liver and skeleton and of their consequences in terms of internal dosimetry. The conclusion is that such studies provide very valuable data and should be targeted in the future on some specific tissues and biomolecules. (authors)

  6. Dosimetric applications of the new ICRP lung model

    International Nuclear Information System (INIS)

    James, A.C.

    1994-06-01

    The International Commission on Radiological Protection (ICRP) has adopted a new dosimetric model of the human respiratory tract, to be issued as ICRP Publication 66. This chapter presents a summary of the main measures of the new model. The model is a general update of that in Publication 30, but is significantly broader in scope. It applies explicitly to workers and all members of the public: for inhalation of particles, gases and vapors; evaluation of dose per unit intake or exposure; and interpretation of bioassay data. The approach is fundamentally different from the Publication 30 model which calculates only the average dose to the lungs. The new model takes account of differences in radiosensitivity of respiratory tract tissues, and the wide range of doses they may receive, and calculates specific tissue doses. The model readily incorporates specific information related to the subject (age, physical activity, smoking or health status) or the exposure (aerosol size and chemical form). The application of the new model to calculate equivalent lung dose and effective dose per unit intake is illustrated for several α- and ∂-emitting radionuclides, and the new values obtained are compared with those given by the ICRP Publication 30 lung model

  7. 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.

  8. Development of optimized dosimetric models for HDR brachytherapy

    International Nuclear Information System (INIS)

    Thayalan, K.; Jagadeesan, M.

    2003-01-01

    High dose rate brachytherapy (HDRB) systems are in clinical use for more than four decades particularly in cervical cancer. Optimization is the method to produce dose distribution which assures that doses are not compromised at the treatment sites whilst reducing the risk of overdosing critical organs. Hence HDRB optimization begins with the desired dose distribution and requires the calculations of the relative weighting factors for each dwell position with out changing the source activity. The optimization for Ca. uterine cervix treatment is simply duplication of the dose distribution used for Low dose rate (LDR) applications. In the present work, two optimized dosimetric models were proposed and studied thoroughly, to suit the local clinical conditions. These models are named as HDR-C and HDR-D, where C and D represent configuration and distance respectively. These models duplicate exactly the LDR pear shaped dose distribution, which is a golden standard. The validity of these models is tested in different clinical situations and in actual patients (n=92). These models: HDR-C and HDR-D reduce bladder dose by 11.11% and 10% and rectal dose by 8% and 7% respectively. The treatment time is also reduced by 12-14%. In a busy hospital setup, these models find a place to cater large number of patients, while addressing individual patients geometry. (author)

  9. 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

  10. A comprehensive approach to age-dependent dosimetric modeling

    International Nuclear Information System (INIS)

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

    1987-01-01

    In the absence of age-specific biokinetic models, current retention models of the International Commission of 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 a comprehensive approach to age-dependent dosimetric modeling is discussed 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 of 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. 16 refs.; 3 figs.; 1 table

  11. A revised dosimetric model of the adult head and brain

    International Nuclear Information System (INIS)

    Bouchet, L.G.; Bolch, W.E.; Weber, D.A.

    1996-01-01

    During the last decade, new radiopharmaceutical have been introduced for brain imaging. The marked differences of these tracers in tissue specificity within the brain and their increasing use for diagnostic studies support the need for a more anthropomorphic model of the human brain and head. Brain and head models developed in the past have been only simplistic representations of this anatomic region. For example, the brain within the phantom of MIRD Pamphlet No. 5 Revised is modeled simply as a single ellipsoid of tissue With no differentiation of its internal structures. To address this need, the MIRD Committee established a Task Group in 1992 to construct a more detailed brain model to include the cerebral cortex, the white matter, the cerebellum, the thalamus, the caudate nucleus, the lentiform nucleus, the cerebral spinal fluid, the lateral ventricles, and the third ventricle. This brain model has been included within a slightly modified version of the head model developed by Poston et al. in 1984. This model has been incorporated into the radiation transport code EGS4 so as to calculate photon and electron absorbed fractions in the energy range 10 keV to 4 MeV for each of thirteen sources in the brain. Furthermore, explicit positron transport have been considered, separating the contribution by the positron itself and its associated annihilations photons. No differences are found between the electron and positron absorbed fractions; however, for initial energies of positrons greater than ∼0.5 MeV, significant differences are found between absorbed fractions from explicit transport of annihilation photons and those from an assumed uniform distribution of 0.511-MeV photons. Subsequently, S values were calculated for a variety of beta-particle and positron emitters brain imaging agents. Moreover, pediatric head and brain dosimetric models are currently being developed based on this adult head model

  12. 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

    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...... (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...

  13. 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.

  14. The ICRP task group respiratory tract model - an age-dependent dosimetric model for general application

    International Nuclear Information System (INIS)

    Bailey, M.R.; Birchall, A.

    1992-01-01

    The ICRP Task Group on Human Respiratory Tract Models for Radiological Protection has developed a revised dosimetric model for the respiratory tract. Papers outlining the model, and describing each aspect of it were presented at the Third International Workshop on Respiratory Tract Dosimetry (Albuquerque 1-3 July 1990), the Proceedings of which were recently published in Radiation Protection Dosimetry Volume 38 Nos 1-3 (1991). Since the model had not changed substantially since the Workshop at Albuquerque, only a summary of the paper presented at Schloss Elmau is included in these Proceedings. (author)

  15. Development and design of an antropomorphic model for electron dosimetric purposes

    International Nuclear Information System (INIS)

    Geske, G.; Geske, J.

    1977-01-01

    After discussing some problems related to the planning of therapeutic irradiation with fast electron the benifit of phantoms for electron dosimetric purposes is pointed out. The selection of tissue-equivalent materials for constructing a phantom is dicussed in detail. Finally, a model representing the upper part of a female body is described. (author)

  16. Dosimetric study to voxel model applied to cardiac exams in Nuclear medicine

    International Nuclear Information System (INIS)

    Cassola, V.F.; Silva, A.M. Marques da; Hoff, G.

    2008-01-01

    The objective of this study is to analyze the dosimetry in a simplified model of the region of interest of myocardial perfusion studies considering different descriptions of Tc-99m emission spectra. It aims to assess the implications of these different approaches in the description of Tc-99m spectrum, as well as their dosimetric implications

  17. Evaluating the uncertainty of input quantities in measurement models

    Science.gov (United States)

    Possolo, Antonio; Elster, Clemens

    2014-06-01

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

  18. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, H; Dong, P; Xing, L [Stanford University School of Medicine, Stanford, CA (United States)

    2016-06-15

    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

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

    Directory of Open Access Journals (Sweden)

    VLADANKA PRESBURGER ULNIKOVIĆ

    2011-06-01

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

  1. Photosynthesis-related quantities for education and modeling.

    Science.gov (United States)

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

    2013-11-01

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

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

    International Nuclear Information System (INIS)

    Bair, W.J.

    1992-05-01

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

  3. A Combined Tissue Kinetics and Dosimetric Model of Respiratory Tissue Exposed to Radiation. Final Technical Report

    International Nuclear Information System (INIS)

    John R. Ford

    2005-01-01

    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

  4. 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.

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

    African Journals Online (AJOL)

    ... solving the dose rates to aquatic organisms with emphasis on the coastal areas of Nigeria where oil exploration activities involve the use of radioactive materials. Solution of the dose function representing the baseline have been modeled the result of which can be employed in assessing future contamination in the area.

  6. Prospective assessment of dosimetric/physiologic-based models for predicting radiation pneumonitis

    International Nuclear Information System (INIS)

    Kocak, Zafer; Borst, Gerben R.; Zeng Jing; Zhou Sumin; Hollis, Donna R.; Zhang Junan; Evans, Elizabeth S.; Folz, Rodney J.; Wong, Terrence; Kahn, Daniel; Belderbos, Jose S.A.; Lebesque, Joos V.; Marks, Lawrence B.

    2007-01-01

    Purpose: Clinical and 3D dosimetric parameters are associated with symptomatic radiation pneumonitis rates in retrospective studies. Such parameters include: mean lung dose (MLD), radiation (RT) dose to perfused lung (via SPECT), and pre-RT lung function. Based on prior publications, we defined pre-RT criteria hypothesized to be predictive for later development of pneumonitis. We herein prospectively test the predictive abilities of these dosimetric/functional parameters on 2 cohorts of patients from Duke and Netherlands Cancer Institute (NKI). Methods and Materials: For the Duke cohort, 55 eligible patients treated between 1999 and 2005 on a prospective IRB-approved study to monitor RT-induced lung injury were analyzed. A similar group of patients treated at the NKI between 1996 and 2002 were identified. Patients believed to be at high and low risk for pneumonitis were defined based on: (1) MLD; (2) OpRP (sum of predicted perfusion reduction based on regional dose-response curve); and (3) pre-RT DLCO. All doses reflected tissue density heterogeneity. The rates of grade ≥2 pneumonitis in the 'presumed' high and low risk groups were compared using Fisher's exact test. Results: In the Duke group, pneumonitis rates in patients prospectively deemed to be at 'high' vs. 'low' risk are 7 of 20 and 9 of 35, respectively; p = 0.33 one-tailed Fisher's. Similarly, comparable rates for the NKI group are 4 of 21 and 6 of 44, respectively, p = 0.41 one-tailed Fisher's. Conclusion: The prospective model appears unable to accurately segregate patients into high vs. low risk groups. However, considered retrospectively, these data are consistent with prior studies suggesting that dosimetric (e.g., MLD) and functional (e.g., PFTs or SPECT) parameters are predictive for RT-induced pneumonitis. Additional work is needed to better identify, and prospectively assess, predictors of RT-induced lung injury

  7. 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

  8. Human respiratory tract model for radiological protection: A revision of the ICRP Dosimetric Model for the Respiratory System

    International Nuclear Information System (INIS)

    Bair, W.J.

    1989-01-01

    In 1984, the International Commission on Radiological Protection (ICRP) appointed a task group of Committee 2 to review and revise, as necessary, the ICRP Dosimetric Model for the Respiratory System. The model was originally published in 1966, modified slightly in Publication No. 19, and again in Publication No. 30 (in 1979). The task group concluded that research during the past 20 y suggested certain deficiencies in the ICRP Dosimetric Model for the Respiratory System. Research has also provided sufficient information for a revision of the model. The task group's approach has been to review, in depth, morphology and physiology of the respiratory tract; deposition of inhaled particles in the respiratory tract; clearance of deposited materials; and the nature and specific sites of damage to the respiratory tract caused by inhaled radioactive substances. This review has led to a redefinition of the regions of the respiratory tract for dosimetric purposes. The redefinition has a morphologic and physiological basis and is consistent with observed deposition and clearance of particles and with resultant pathology. Regions, as revised, are the extrathoracic (E-T) region, comprising the nasal and oral regions, the pharynx, larynx, and upper part of the trachea; the fast-clearing thoracic region (T[f]), comprising the remainder of the trachea and bronchi; and the slow-clearing thoracic region (T[s]), comprising the bronchioles, alveoli, and thoracic lymph nodes. A task group report will include models for calculating radiation doses to these regions of the respiratory tract following inhalation of representative alpha-, beta-, and gamma-emitting particulate and gaseous radionuclides. The models may be implemented as a package of computer codes available to a wide range of users

  9. 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

  10. 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.

  11. EchoSeed Model 6733 Iodine-125 brachytherapy source: Improved dosimetric characterization using the MCNP5 Monte Carlo code

    Energy Technology Data Exchange (ETDEWEB)

    Mosleh-Shirazi, M. A.; Hadad, K.; Faghihi, R.; Baradaran-Ghahfarokhi, M.; Naghshnezhad, Z.; Meigooni, A. S. [Center for Research in Medical Physics and Biomedical Engineering and Physics Unit, Radiotherapy Department, Shiraz University of Medical Sciences, Shiraz 71936-13311 (Iran, Islamic Republic of); Radiation Research Center and Medical Radiation Department, School of Engineering, Shiraz University, Shiraz 71936-13311 (Iran, Islamic Republic of); Comprehensive Cancer Center of Nevada, Las Vegas, Nevada 89169 (United States)

    2012-08-15

    This study primarily aimed to obtain the dosimetric characteristics of the Model 6733 {sup 125}I seed (EchoSeed) with improved precision and accuracy using a more up-to-date Monte-Carlo code and data (MCNP5) compared to previously published results, including an uncertainty analysis. Its secondary aim was to compare the results obtained using the MCNP5, MCNP4c2, and PTRAN codes for simulation of this low-energy photon-emitting source. The EchoSeed geometry and chemical compositions together with a published {sup 125}I spectrum were used to perform dosimetric characterization of this source as per the updated AAPM TG-43 protocol. These simulations were performed in liquid water material in order to obtain the clinically applicable dosimetric parameters for this source model. Dose rate constants in liquid water, derived from MCNP4c2 and MCNP5 simulations, were found to be 0.993 cGyh{sup -1} U{sup -1} ({+-}1.73%) and 0.965 cGyh{sup -1} U{sup -1} ({+-}1.68%), respectively. Overall, the MCNP5 derived radial dose and 2D anisotropy functions results were generally closer to the measured data (within {+-}4%) than MCNP4c and the published data for PTRAN code (Version 7.43), while the opposite was seen for dose rate constant. The generally improved MCNP5 Monte Carlo simulation may be attributed to a more recent and accurate cross-section library. However, some of the data points in the results obtained from the above-mentioned Monte Carlo codes showed no statistically significant differences. Derived dosimetric characteristics in liquid water are provided for clinical applications of this source model.

  12. 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

  13. A Model to Determinate the Influence of Probability Density Functions (PDFs of Input Quantities in Measurements

    Directory of Open Access Journals (Sweden)

    Jesús Caja

    2016-06-01

    Full Text Available A method for analysing the effect of different hypotheses about the type of the input quantities distributions of a measurement model is presented here so that the developed algorithms can be simplified. As an example, a model of indirect measurements with optical coordinate measurement machine was employed to evaluate these different hypotheses. As a result of the different experiments, the assumption that the different variables of the model can be modelled as normal distributions is proved.

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

    OpenAIRE

    M. Pattnaik

    2013-01-01

    For several decades, the Economic Order Quantity (EOQ) model and its variations have received much attention from researchers. Recently, there has been an investigation into an EOQ model incorporating effect of units lost due to deterioration in infinite planning horizon with crisp decision environment. Accounting for holding and ordering cost, as has traditionally been the case of modeling inventory systems in fuzzy environment are investigated which are not precisely known and defined on a ...

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Ata Allah Taleizadeh

    2011-04-01

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

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

    OpenAIRE

    Gholamreza Raisali; Mahdi Sadeghi; Vahideh Ataeinia; Arjang Shahvar; Maryam Ghasemi Ghonchehnazi

    2008-01-01

    Introduction: The use of low energy isotopes such as  103 Pd in brachytherapy for the treatment of cancers  such as prostate, eye, head, neck, breast and cervix is increasing. In this regard, different models of Pd- 103  seeds  have  been  designed  and  manufactured  at  the  Agricultural,  Medical  and  Industrial  Research  School (AMIRS) of Atomic Energy Organization of Iran. In this research, the dosimetric parameters of  the second model of Pd-103 seed manufactured at AMIRS have been ca...

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

    Directory of Open Access Journals (Sweden)

    Milad Elyasi

    2014-04-01

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

  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. 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.

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

    OpenAIRE

    Tai, Allen H.

    2012-01-01

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

  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

    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

  5. 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.

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

    Directory of Open Access Journals (Sweden)

    M. Pattnaik

    2013-07-01

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

  7. 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

    -UA), an approach based on a multi-objective auto-calibration (a multialgorithm, genetically adaptive multiobjective method, AMALGAM) and a Bayesian approach based on a simplified Markov Chain Monte Carlo method (implemented in the software MICA). To allow a meaningful comparison among the different uncertainty...... techniques, common criteria have been set for the likelihood formulation, defining the number of simulations, and the measure of uncertainty bounds. Moreover, all the uncertainty techniques were implemented for the same case study, in which the same stormwater quantity and quality model was used alongside...... the same dataset. The comparison results for a well-posed rainfall/runoff model showed that the four methods provide similar probability distributions of model parameters, and model prediction intervals. For ill-posed water quality model the differences between the results were much wider; and the paper...

  8. 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.

  9. Experimental determination of dosimetric characterization of a newly designed encapsulated interstitial brachytherapy source of 103Pd-model Pd-1

    International Nuclear Information System (INIS)

    Nath, Ravinder; Yue Ning; Roa, Eduardo

    2002-01-01

    A newly designed encapsulated 103 Pd source has been introduced (BrachySeed trade mark sign -Pd-103, also named Model Pd-1, manufactured by DRAXIMAGE Inc. and distributed by Cytogen Corp.) for interstitial brachytherapy to provide more isotropic dose distributions. In this work, the dosimetric characteristics of the 103 Pd source were measured with micro LiF TLD chips and dosimetry parameters were characterized based upon the American Association of Physicists in Medicine (AAPM) Task Group No. 43 formalism. The dose rate constant of the sources was determined to be 0.66±0.05 cGy h-1 U-1. The radial dose function was measured and was found to be similar to that of the Theragenics Model 200 103 Pd source. The anisotropy constant for the Model Pd-1 source was determined to be 1.03

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Gholamreza Raisali

    2008-06-01

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

  12. 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......In the literature we find two opposing hypotheses relating the volume of money to the volume of transactions or national income. The classic hypothesis, implicitly entailed in the quantity equation, argues that this relation must be positive, while an opposing hypothesis, most strongly presented...

  13. 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.

  14. 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

    In this work, multilayered perceptron neural networks (MLPNNs) were presented for the computation of the gamma-ray energy absorption buildup factors (BA) of seven thermoluminescent dosimetric (TLD) materials [LiF, BeO, Na2B4O7, CaSO4, Li2B4O7, KMgF3, Ca3(PO4)2] in the energy region 0.015–15Me......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...

  15. 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.

  16. 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

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    Monalisha Pattnaik

    2014-09-01

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

  19. Dosimetric model for antibody targeted radionuclide therapy of tumor cells in cerebrospinal fluid

    International Nuclear Information System (INIS)

    Millar, W.T.; Barrett, A.

    1990-01-01

    Although encouraging results have been obtained using systemic radioimmunotherapy in the treatment of cancer, it is likely that regional applications may prove more effective. One such strategy is the treatment of central nervous system leukemia in children by intrathecal instillation of targeting or nontargeting beta particle emitting radionuclide carriers. The beta particle dosimetry of the spine is assessed, assuming that the spinal cord and the cerebrospinal fluid compartment can be adequately represented by a cylindrical annulus. The radionuclides investigated were 90 Y, 131 I, 67 Cu, and 199 Au. It is shown that the radiation dose to the cord can be significantly reduced using short range beta particle emitters and that there is little advantage in using targeting carriers with these radionuclides. 199 Au and 67 Cu also have the advantage of having a suitable gamma emission for imaging, permitting pretherapy imaging and dosimetric calculations to be undertaken prior to therapy. If these methods prove successful, it may be possible to replace the external beam component used in the treatment of central nervous system leukemia in children by intrathecal radionuclide therapy, thus reducing or avoiding side effects such as growth and intellectual impairment

  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. The application of data derived from autoradiographic studies with 241Pu in the formulation of a bone dosimetric model for 239Pu

    International Nuclear Information System (INIS)

    Priest, N.D.; Hunt, B.W.

    1979-01-01

    Recently a dosimetric model for 239 Pu in bone has been published which in conjunction with the general ICRP dosimetric model for actinides is used to calculate annual limits of intake for 239 Pu. This model allows for the burial of plutonium in bone, for the recycling of plutonium within the skeleton and for the retention of plutonium in the bone marrow. The model was based upon published descriptions of the distribution and redistribution patterns of plutonium in bone and on evidence obtained from autoradiographic studies of bone from animals injected with 241 Pu. The experiments with 241 Pu demonstrated the initial uptake of plutonium by bone surfaces. As a result of the growth and drift processes much of this plutonium became either buried in the bone or was retained within macrophages in the bone marrow. (author)

  2. Urban Hydrology and Water Quality Modeling - Resolution Modeling Comparison for Water Quantity and Quality

    Science.gov (United States)

    Fry, T. J.; Maxwell, R. M.

    2014-12-01

    Urbanization presents challenging water resource problems for communities worldwide. The hydromodifications associated with urbanization results in increased runoff rates and volumes and increased peak flows. These hydrologic changes can lead to increased erosion and stream destabilization, decreased evapotranspiration, decreased ground water recharge, increases in pollutant loading, and localized anthropogenic climate change or Urban Heat Islands. Stormwater represents a complex and dynamic component of the urban water cycle that requires careful mitigation. With the implementation of Phase II rules under the CWA, stormwater management is shifting from a drainage-efficiency focus to a natural systems focus. The natural system focus, referred to as Low Impact Development (LID), or Green Infrastructure, uses best management practices (BMPs) to reduce the impacts caused by urbanization hydromodification. Large-scale patterns of stormwater runoff from urban environments are complex and it is unclear what the large-scale impacts of green infrastructure are on the water cycle. High resolution physically based hydrologic models can be used to more accurately simulate the urban hydrologic cycle. These types of models tend to be more dynamic and allow for greater flexibility in evaluating and accounting for various hydrologic processes in the urban environment that may be lost with lower resolution conceptual models. We propose to evaluate the effectiveness of high resolution models to accurately represent and determine the urban hydrologic cycle with the overall goal of being able to accurately assess the impacts of LID BMPs in urban environments. We propose to complete a rigorous model intercomparison between ParFlow and FLO-2D. Both of these models can be scaled to higher resolutions, allow for rainfall to be spatially and temporally input, and solve the shallow water equations. Each model is different in the way it accounts for infiltration, initial abstraction losses

  3. 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.

  4. 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.

  5. 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)

  6. Dosimetric fundamentals

    International Nuclear Information System (INIS)

    Nahum, A.E.

    2004-01-01

    This text covers some important concepts in radiation dosimetry with an emphasis on cavity theory, i.e. the theoretical evaluation of D med /D det , for two important classes of detector, 'large' and Bragg-Gray. Monte Carlo simulation continues to play a major role in evaluating this expression through its ability to compute the fluence spectra of electrons and photons as a function of their position in a medium. The key results in the paper can be summarised thus: - Fluence Φ = dN/da Σds/dV and is a scalar quantity. - Kerma K = dE tr /dm, i.e. kinetic energy (k.e.) transferred per unit mass; collision kerma K c excludes charged-particle k.e. converted to Bremsstrahlung. - Kerma and fluence are related by K med = Φ (μ tr /ρ) med for photons of energy E; for collision kerma, K c , the mass energy-absorption coefficient μ en replaces μ tr . - D med = (K c ) med under conditions of charged particle equilibrium (CPE), for a medium med irradiated by photons. - For a fluence Φ of charged particles, e.g. electrons, in medium med, the absorbed dose D med = Φ (S col /ρ) med provided there is δ-ray equilibrium. - For large detectors under photon irradiation (i.e. in which there is CPE as e - ranges - detector size), D med /D det is given by (μ en /ρ) med /(μ en /ρ) det which is evaluated over the photon spectrum at the detector position: e.g. TLD (e.g. LiF) in kV X-ray beams are large. - For 'small' or Bragg-Gray detectors under photon or electron irradiation (e - ranges - detector dimensions), D med /D det is given by (S col /ρ) med /(S col /ρ) det , the (mass) stopping-power ratio, usually written S med.det : e.g. (air-filled) ionisation chambers behave as Bragg -Gray detectors in megavoltage photon and electron beams, but not in kV X-ray beams. - Bragg-Gray theory was extended by Spencer and Attix to take into account the finite range of δ-rays. - General cavity theory provides an approximate treatment of detectors which are neither 'large' nor 'small

  7. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-15

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

  9. Computerized tomography in Community of Madrid. Reference dosimetric measurements

    International Nuclear Information System (INIS)

    Ruiz Sanz, S.; Calzado, A.; Melchor, M.; Marco, M.

    1994-01-01

    A total of about 43 computed tomography scanners were operating in the Autonomous Community of Madrid during 1991. A sample of 14 facilities was selected to perform dosimetric measurements in order to obtain characteristic dose profiles. From these, some quantities as the computed tomography dose index and the enhancement factor were calculated and analysed for the most common technique settings. Relations were established between the dosimetric results and technical characteristics of the scanners. (Author)

  10. Applications of sensitivity function to dosimetric data adjustments

    International Nuclear Information System (INIS)

    Nakazawa, Masaharu

    1984-01-01

    Sensitivity functions are applied to the dosimetric field in the spectrum unfolding technique, also called as the data adjustment technique which are statistical estimation procedures of the neutron spectrum or relating dosimetric quantities basing on the reaction-rate data measurements. Using the practical formulae and numerical examples of the sensitivity functions in the dosimetric data adjustments, two comments are made that (1) present sensitivity values are highly depending on the initial spectrum inputs and (2) more attention should be paid to the dependency of the sensitivity on the very uncertain covariance data inputs of the initial neutron spectrum. (author)

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

    OpenAIRE

    Salla, Marcio Ricardo; Paredes-Arquiola, Javier; Solera, Abel; Álvarez, Joaquín Andreu; Pereira, Carlos Eugênio; Alamy Filho, José Eduardo; De Oliveira, André Luiz

    2014-01-01

    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 reali...

  12. 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.

  13. Theoretical and experimental determination of dosimetric characteristics for brachyseed{sup TM} Pd-103, model Pd-1, source

    Energy Technology Data Exchange (ETDEWEB)

    Meigooni, A.S. E-mail: alimeig@pop.uky.edu; Zhang Hualin; Perry, Candace; Dini, S.A.; Koona, R.A

    2003-05-01

    Dosimetric characteristics of the BrachySeed{sup 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{sup TM} using LiF TLD chips. Theoretical simulation calculations were performed in both Solid Water{sup 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{sup -1} U{sup -1} and 0.61 cGy h{sup -1} U{sup -1} in water and Solid Water{sup TM}, respectively. The measured dose rate constant in Solid Water{sup TM} was found to be 0.63{+-}7% cGy h{sup -1} U{sup -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{sup TM} at the radial distances of 1 to 7 cm. Measurements were made in Solid Water{sup 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.

  14. 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

  15. SU-D-BRE-03: Dosimetric Impact of In-Air Spot Size Variations for Commissioning a Room-Matched Beam Model for Pencil Beam Scanning Proton Therapy

    International Nuclear Information System (INIS)

    Zhang, Y; Giebeler, A; Mascia, A; Piskulich, F; Perles, L; Lepage, R; Dong, L

    2014-01-01

    Purpose: To quantitatively evaluate dosimetric consequence of spot size variations and validate beam-matching criteria for commissioning a pencil beam model for multiple treatment rooms. Methods: A planning study was first conducted by simulating spot size variations to systematically evaluate dosimetric impact of spot size variations in selected cases, which was used to establish the in-air spot size tolerance for beam matching specifications. A beam model in treatment planning system was created using in-air spot profiles acquired in one treatment room. These spot profiles were also acquired from another treatment room for assessing the actual spot size variations between the two treatment rooms. We created twenty five test plans with targets of different sizes at different depths, and performed dose measurement along the entrance, proximal and distal target regions. The absolute doses at those locations were measured using ionization chambers at both treatment rooms, and were compared against the calculated doses by the beam model. Fifteen additional patient plans were also measured and included in our validation. Results: The beam model is relatively insensitive to spot size variations. With an average of less than 15% measured in-air spot size variations between two treatment rooms, the average dose difference was −0.15% with a standard deviation of 0.40% for 55 measurement points within target region; but the differences increased to 1.4%±1.1% in the entrance regions, which are more affected by in-air spot size variations. Overall, our single-room based beam model in the treatment planning system agreed with measurements in both rooms < 0.5% within the target region. For fifteen patient cases, the agreement was within 1%. Conclusion: We have demonstrated that dosimetrically equivalent machines can be established when in-air spot size variations are within 15% between the two treatment rooms

  16. 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

  17. 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.)

  18. Evolution of dosimetric phantoms

    International Nuclear Information System (INIS)

    Reddy, A.R.

    2010-01-01

    In this oration evolution of the dosimetric phantoms for radiation protection and for medical use is briefly reviewed. Some details of the development of Indian Reference Phantom for internal dose estimation are also presented

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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

  20. 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.

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

    Science.gov (United States)

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

    2015-05-01

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

  2. A review of dosimetric and toxicity modeling of proton versus photon craniospinal irradiation for pediatrics medulloblastoma.

    Science.gov (United States)

    Ho, Evangeline S Q; Barrett, Sarah A; Mullaney, Laura M

    2017-08-01

    Craniospinal irradiation (CSI) is the standard radiation therapy treatment for medulloblastoma. Conventional CSI photon therapy (Photon-CSI) delivers significant dose to surrounding normal tissue (NT). Research into pediatric CSI with proton therapy (Proton-CSI) has increased, with the aim of exploiting the potential to reduce NT dose and associated post-treatment complications. This review aims to compare treatment outcomes of pediatric medulloblastoma patients between Proton- and Photon-CSI treatments. A search and review of studies published between 1990 and 2016 comparing pediatric (2-18 years) medulloblastoma Proton- and Photon-CSI in three aspects - normal organ sparing and target coverage; normal organ dysfunction and second malignancy risks - was completed. Fifteen studies were selected for review and the results were directly compared. Proton-CSI reported improved out-of-field organ sparing while target coverage improvements were inconsistent. Normal organ dysfunction risks were predicted to be lower following Proton-CSI. Secondary malignancy risks (SMRs) were generally lower with Proton-CSI based on several different risk models. Proton-CSI conferred better treatment outcomes than Photon-CSI for pediatric medulloblastoma patients. This review serves to compare the current literature in the absence of long-term data from prospective studies.

  3. Data file on retention and excretion of inhaled radionuclides calculated using ICRP dosimetric models

    International Nuclear Information System (INIS)

    Ishigure, Nobuhito; Nakano, Takashi; Enomoto, Hiroko; Shimo, Michikuni; Inaba, Jiro

    2000-01-01

    The authors have computed whole-body or a specific organ content and the daily urinary and faecal excretion rate of some selected radionuclides following acute intake by inhalation and ingestion, where the ICRP new respiratory tract model (ICRP Publication 66) and the latest ICRP biokinetic models were applied. The results were compiled in a file of MS Excel. The file was tentatively called MONDAI for reference. MONDAI contains the data for all radionuclides in ICRP Publications 54 and 78 and, in addition, some other radionuclides which are important from the viewpoint of occupational exposure in nuclear industry, research and medicine. They are H-3, P-32, Cr-51, Mn-54, Fe-59, Co-57, Co-58, Co-60, Zn-65, Rb-86, Sr-85, Sr-89, Sr-90, Zr-95, Ru-106, Ag-110m, Sb-124, Sb-125, I-125, I-129, I-131, Cs-134, Cs-137, Ba-140, Ce-141, Ce-144, Hg-203, Ra-226, Ra-228, Th-228, Th-232, U-234, U-235, U-238, Np-237, Pu-238, Pu-239, Pu-240, Am-241, Cm-242, Cm-244 and Cf-252. The day-by-day data up to 1000 days and the data at every 10 days up to 10000 days are presented. The following ICRP default values for the physical characteristics of the radioactive aerosols were used: AMAD=5 micron, geometric SD=2.5, particle density = 3 g/cm 3 , particle shape factor = 1.5. The subject exposed to the aerosols is the ICRP reference worker doing light work: light exercise with the ventilation rate of 1.5 m 3 /h for 5.5 h + sitting with the ventilation rate of 0.54 m 3 /h for 2.5 h. MONDAI was originally made by Version 7.0 of MS Excel for Windows 95, but the file was saved in the form of Ver. 4.0 as well as Ver. 7.0. Therefore, if the user has Ver. 4.0 or an upper version, he can open the file and operate it. With the graph-wizard of MS Excel the user can easily make a diagram for the retention or daily excretion of a radionuclide of interest. The dose coefficient (Sv/Bq intake) of each radionuclide for each absorption type given in ICRP Publication 68 was also written in each sheet. Therefore

  4. 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.

  5. Application of the dosimetric model described by Humm to target 131I monoclonal antibodies to leukaemic cells in the cerebrospinal fluid

    International Nuclear Information System (INIS)

    Papanastassiou, V.; Pizer, B.L.; Kemshead, J.T.

    1993-01-01

    In 1986 Humm suggested a dosimetric model for targeted radiation therapy that considered both the physical characteristics of the radionuclide used and the morphology of the targeted tumour. Using this model he described the dose advantage due to antibody binding in terms of a ratio of tumour radiation dose to that of normal tissue. The model applied to non-solid tumours assumes no cell clumping and hence no cross-fire effect. The authors demonstrate the direct application of the model to a particular clinical scenario; the targeting of 131 I monoclonal antibodies to leukaemic cells within the cerebrospinal fluid (CSF). In this situation the dose advantage is much higher than the figure reported by Humm, which was arrived at by considering a more general application of the model. (author)

  6. Numeric model to predict the location of market demand and economic order quantity for retailers of supply chain

    Science.gov (United States)

    Fradinata, Edy; Marli Kesuma, Zurnila

    2018-05-01

    Polynomials and Spline regression are the numeric model where they used to obtain the performance of methods, distance relationship models for cement retailers in Banda Aceh, predicts the market area for retailers and the economic order quantity (EOQ). These numeric models have their difference accuracy for measuring the mean square error (MSE). The distance relationships between retailers are to identify the density of retailers in the town. The dataset is collected from the sales of cement retailer with a global positioning system (GPS). The sales dataset is plotted of its characteristic to obtain the goodness of fitted quadratic, cubic, and fourth polynomial methods. On the real sales dataset, polynomials are used the behavior relationship x-abscissa and y-ordinate to obtain the models. This research obtains some advantages such as; the four models from the methods are useful for predicting the market area for the retailer in the competitiveness, the comparison of the performance of the methods, the distance of the relationship between retailers, and at last the inventory policy based on economic order quantity. The results, the high-density retail relationship areas indicate that the growing population with the construction project. The spline is better than quadratic, cubic, and four polynomials in predicting the points indicating of small MSE. The inventory policy usages the periodic review policy type.

  7. Bioeffect modeling and equieffective dose concepts in radiation oncology – Terminology, quantities and units

    International Nuclear Information System (INIS)

    Bentzen, Søren M.; Dörr, Wolfgang; Gahbauer, Reinhard; Howell, Roger W.; Joiner, Michael C.; Jones, Bleddyn; Jones, Dan T.L.; Kogel, Albert J. van der; Wambersie, André; Whitmore, Gordon

    2012-01-01

    The International Commission on Radiation Units and Measurements (ICRU) Report Committee on “Bioeffect Modeling and Biologically Equivalent Dose Concepts in Radiation Therapy” is currently developing a comprehensive and consistent framework for radiobiological effect modeling based on the equieffective dose, EQDX α/β , a concept encompassing BED and EQD2 as special cases.

  8. Generalized symmetries and conserved quantities of the Lotka-Volterra model

    Science.gov (United States)

    Baumann, G.; Freyberger, M.

    1991-07-01

    We examine the generalized symmetries of the Lotka-Volterra model to find the parameter values at which one time-dependent integral of motion exists. In this case the integral can be read off from the symmetries themselves. We also demonstrate the connection to a Hamiltonian structure of the Lotka-Volterra model.

  9. a model for quantity estimation for multi-coded team events

    African Journals Online (AJOL)

    Participation in multi-coded sports events often involves travel to international ... Medication use by Team south africa during the XXVIIIth olympiad: a model .... individual sports included in the programme (e.g. athletes involved in contact sports ...

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

    OpenAIRE

    Monalisha Pattnaik

    2014-01-01

    Background: This model presents the effect of deteriorating items in fuzzy optimal instantaneous replenishment for finite planning horizon. Accounting for holding cost per unit per unit time and ordering cost per order have traditionally been the case of modeling inventory systems in fuzzy environment. These imprecise parameters defined on a bounded interval on the axis of real numbers and the physical characteristics of stocked items dictate the nature of inventory policies implemented ...

  11. 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)

  12. 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...

  13. Clarification of the confusion concerning the crystal-field quantities vs the zero-field splitting quantities in magnetism studies: Part II-Survey of literature dealing with model studies of spin systems

    International Nuclear Information System (INIS)

    Rudowicz, C.

    2008-01-01

    For respective quantities, i.e., Hamiltonians, parameters, and energy level splittings, related to two physically distinct notions X and Y, various cases of confused terminology have been identified in literature. Referring to a quantity related actually to the notion Y using incorrectly the name of another well-defined notion X constitutes, what may be defined for short as, the type X=Y confusion. An ongoing survey of magnetism literature indicates that quantities related to zero-field splitting (ZFS) or equivalently fine structure (FS) are most often confused with those related to crystal-field (CF) or equivalently ligand field (LF). In this review the CF=ZFS confusion cases, i.e., labelling actual ZFS/FS quantities as purportedly 'CF/LF' ones, appearing in magnetism studies are surveyed and clarified. Part I covers the cases occurring in literature dealing with specific compounds. In this part model studies of spin systems are surveyed. The cases of terminology mixing up actual ZFS/FS quantities with purported CF/LF ones are identified and presented comprehensively in tabular form. To facilitate discussion, problems pertinent for the CF=ZFS confusion are categorized into several groups, including origin of the two notions, physical consequences, usage of specific numerical values, invoking real magnetic spin systems, and properties of spin S=1/2 systems. Physical implications of this confusion for interpretation of model results are also considered. Overall implications of incorrect terminology go beyond simple semantic issues and concern possible misinterpretation of data describing various physical properties of models studied. Such terminology contributes also to misleading keyword classifications of papers in journals and scientific databases. Other types of confusion identified in survey of magnetism literature will be discussed in separate reviews

  14. An economic order quantity model with nonlinear holding cost, partial backlogging and ramp-type demand

    Science.gov (United States)

    San-José, Luis A.; Sicilia, Joaquín; González-de-la-Rosa, Manuel; Febles-Acosta, Jaime

    2018-07-01

    In this article, a deterministic inventory model with a ramp-type demand depending on price and time is developed. The cumulative holding cost is assumed to be a nonlinear function of time. Shortages are allowed and are partially backlogged. Thus, the fraction of backlogged demand depends on the waiting time and on the stock-out period. The aim is to maximize the total profit per unit time. To do this, a procedure that determines the economic lot size, the optimal inventory cycle and the maximum profit is presented. The inventory system studied here extends diverse inventory models proposed in the literature. Finally, some numerical examples are provided to illustrate the theoretical results previously propounded.

  15. The modelling of solar radiation quantities and intensities in a two dimensional compound parabolic collector

    OpenAIRE

    2010-01-01

    M.Ing. A dissertation presented on the basic solar design principles such as sun-earth geometry, energy wavelengths, optics, incidence angles, parabolic collector configurations and design, materials for solar applications, efficiencies, etc to be considered in Solar Concentrating Collector design. These principles were applied in the design and fabrication of a prototype solar collector. The solar collector was tested to verify and correct mathematical models that were generated from exis...

  16. New estimates on various critical/universal quantities of the 3d Ising model

    International Nuclear Information System (INIS)

    Hasenbusch, M.

    1998-01-01

    We present estimates for the 3D Ising model on the cubic lattice, both regarding interface and bulk properties. We have results for the interface tension, in particular the amplitude σ 0 in the critical law σ=ρ 0 t μ , and for the universal combination R - =σξ 2 . Concerning the bulk properties, we estimate the specific heat universal amplitude ratio A + /A - , together with the exponent α, the nonsingular background of energy and specific heat at criticality, together with the exponent ν. There are also results for the universal combination f s ξ 3 , where f s is the singular part of the free energy. (orig.)

  17. Exact evaluation of entropic quantities in a solvable two-particle model

    International Nuclear Information System (INIS)

    Glasser, M.L.; Nagy, I.

    2013-01-01

    It has long been known that the von Neumann entropy S N and the Jozsa–Robb–Wootters subentropy Q JRW [R. Jozsa, et al., Phys. Rev. A 49 (1994) 668] are, respectively, upper and lower bounds on the accessible information one can obtain about the identity of a pure state by performing a quantum measurement on a system whose pure state is initially unknown. We determine these bounds exactly in terms of the occupation numbers of normalized natural orbitals of an externally confined interacting two-particle model system. The occupation numbers are obtained via a sign-correct direct decomposition of the underlying exact Schrödinger wave function in terms of an infinite sum of products of Löwdin's natural orbitals, avoiding thus the solution of the eigenvalue problem with the corresponding reduced one-particle matrix.

  18. Exact evaluation of entropic quantities in a solvable two-particle model

    Energy Technology Data Exchange (ETDEWEB)

    Glasser, M.L., E-mail: laryg@clarkson.edu [Department of Physics, Clarkson University, Potsdam, NY 13699-5820 (United States); Donostia International Physics Center, P. Manuel de Lardizabal 4, E-20018 San Sebastián (Spain); Nagy, I. [Donostia International Physics Center, P. Manuel de Lardizabal 4, E-20018 San Sebastián (Spain); Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economics, H-1521 Budapest (Hungary)

    2013-11-08

    It has long been known that the von Neumann entropy S{sub N} and the Jozsa–Robb–Wootters subentropy Q{sub JRW} [R. Jozsa, et al., Phys. Rev. A 49 (1994) 668] are, respectively, upper and lower bounds on the accessible information one can obtain about the identity of a pure state by performing a quantum measurement on a system whose pure state is initially unknown. We determine these bounds exactly in terms of the occupation numbers of normalized natural orbitals of an externally confined interacting two-particle model system. The occupation numbers are obtained via a sign-correct direct decomposition of the underlying exact Schrödinger wave function in terms of an infinite sum of products of Löwdin's natural orbitals, avoiding thus the solution of the eigenvalue problem with the corresponding reduced one-particle matrix.

  19. The Implementation of ABC Classification and (Q, R with Economic Order Quantity (EOQ Model on the Travel Agency

    Directory of Open Access Journals (Sweden)

    Anggi Oktaviani

    2017-03-01

    Full Text Available To support customer loyalty programs, the travel agencies gave a souvenir to their customers. In one of the travel agencies in Jakarta, the demand for travel agency services could not be ensured. This had an impact on inventory items that were surplus to requirements. Inventory management was done by combining classifications ABC and (Q, R with Economic Order Quantity (EOQ model, which was usually used for uncertain demand. With “A” classification of the goods, two model (Q, R scenarios were made and then simulated with software Arena. From these two scenarios, the results show that both have a tendency to decline, or the stockouts occur. However, the second scenario is more optimistic because a dummy variable is added the second scenario. Thus, the tendency is stable and does not decline.

  20. 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.

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

    Science.gov (United States)

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

    2013-01-01

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

  2. Dosimetric effects of saline- versus water-filled balloon applicators for IORT using the model S700 electronic brachytherapy source.

    Science.gov (United States)

    Redler, Gage; Templeton, Alistair; Zhen, Heming; Turian, Julius; Bernard, Damian; Chu, James C H; Griem, Katherine L; Liao, Yixiang

    The Xoft Axxent Electronic Brachytherapy System (Xoft, Inc., San Jose, CA) is a viable option for intraoperative radiation therapy (IORT) treatment of early-stage breast cancer. The low-energy (50-kVp) X-ray source simplifies shielding and increases relative biological effectiveness but increases dose distribution sensitivity to medium composition. Treatment planning systems typically assume homogenous water for brachytherapy dose calculations, including precalculated atlas plans for Xoft IORT. However, Xoft recommends saline for balloon applicator filling. This study investigates dosimetric differences due to increased effective atomic number (Z eff ) for saline (Z eff  = 7.56) versus water (Z eff  = 7.42). Balloon applicator diameters range from 3 to 6 cm. Monte Carlo N-Particle software is used to calculate dose at the surface (D s ) of and 1 cm away (D 1cm ) from the water-/saline-filled balloon applicator using a single dwell at the applicator center as a simple estimation of the dosimetry and multiple dwells simulating the clinical dose distributions for the atlas plans. Single-dwell plans show a 4.4-6.1% decrease in D s for the 3- to 6-cm diameter applicators due to the saline. Multidwell plans show similar results: 4.9% and 6.4% D s decrease, for 4-cm and 6-cm diameter applicators, respectively. For the single-dwell plans, D 1cm decreases 3.6-5.2% for the 3- to 6-cm diameter applicators. For the multidwell plans, D 1cm decreases 3.3% and 5.3% for the 4-cm and 6-cm applicators, respectively. The dosimetric effect introduced by saline versus water filling for Xoft balloon applicator-based IORT treatments is ∼5%. Users should be aware of this in the context of both treatment planning and patient outcome studies. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  3. 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

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

    Directory of Open Access Journals (Sweden)

    Zohreh Molamohamadi

    2014-01-01

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

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

    International Nuclear Information System (INIS)

    Hiatt, Jessica R.; Davis, Stephen D.; Rivard, Mark J.

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-15

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

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

    Science.gov (United States)

    Hiatt, Jessica R; Davis, Stephen D; Rivard, Mark J

    2015-06-01

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

  8. Dosimetric data for the fetus derived from an anatomical model of its mother at the end of the first trimester

    International Nuclear Information System (INIS)

    Davis, J.L.; Stabin, M.G.; Cristy, M.; Ryman, J.C.

    1986-01-01

    We discuss a study of the radiation transport of monoenergetic photons within a mathematical phantom of the pregnant female at the end of the first trimester. This phantom was developed from the adult female member of the ORNL phantom series with modifications reflecting anatomical changes at this stage of pregnancy. This geometry was incorporated into the ALGAMP Monte Carlo radiation transport code used at ORNL with the phantom series. For internal sources of radiation the emission of 60,000 monoenergetic photons at each of 12 energies within 30 organs of the body was simulated. Energy deposition within 158 regions of the body, including uterine wall, uterine contents, and 12 subregions within the contents, was tabulated. The results are presented in terms of the specific absorbed fraction, i.e., the fraction of the photon energy emitted within a source organ that is absorbed per unit mass of the target region. The specific absorbed fraction data are commonly used to evaluate the dose associated with internal emitters, e.g., from administered radiopharmaceuticals. Additional calculations have been performed for a uniform, isotropic field of photons incident on the surface of the phantom; these data provide information on the shielding of the fetus by the mother and are of interest in evaluation of doses from external radiation fields. In this study we have provided dosimetric information useful in making quantitative risk estimates for the developing fetus. Our investigations demonstrate that even at this early stage in pregnancy the effective dose equivalent to the mother cannot be used as an index of the dose equivalent to the fetus. Further efforts will be directed to consideration of later stages in fetal development and consideration of irradiation by external neutron fields

  9. 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.

  10. 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)

  11. 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

  12. Monte Carlo investigation of the dosimetric properties of the new 103Pd BrachySeedTMPd-103 Model Pd-1 source

    International Nuclear Information System (INIS)

    Chan, Gordon H.; Prestwich, William V.

    2002-01-01

    Recently, 103 Pd brachytherapy sources have been increasingly used for interstitial implants as an alternative to 125 I sources. The BrachySeed TM Pd-103 Model Pd-1 seed is one of the latest in a series of new brachytherapy sources that have become available commercially. The dosimetric properties of the seed were investigated by Monte Carlo simulation, which was performed using the Integrated Tiger Series CYLTRAN code. Following the AAPM Task Group 43 formalism, the dose rate constant, radial dose function, and anisotropy parameters were determined. The dose rate constant, Λ, was calculated to be 0.613±3% cGy h -1 U -1 . This air kerma strength was derived from Monte Carlo simulation using the point extrapolation method. The radial dose function, g(r), was computed at distances from 0.15 to 10 cm. The anisotropy function, F(r,θ), and anisotropy factor, φ an (r), were calculated at distances from 0.5 to 7 cm. The anisotropy constant, φ(bar sign) an , was determined to be 0.978, which is closer to unity than most other 103 Pd seeds, indicating a high degree of uniformity in dose distribution. The dose rate constant and the radial dose function were also investigated by analytical modeling, which served as an independent evaluation of the Monte Carlo data, and found to be in good agreement with the Monte Carlo results

  13. 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

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

    International Nuclear Information System (INIS)

    Papadimitroulas, P; Kagadis, GC; Loudos, G

    2014-01-01

    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 10 and 0.15*10 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 evaluating the

  15. 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

  16. 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

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

    Science.gov (United States)

    Catarinucci, L; Tarricone, L

    2009-12-01

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

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

    International Nuclear Information System (INIS)

    Catarinucci, L.; Tarricone, L.

    2009-01-01

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

  19. Radiation quantities and units

    International Nuclear Information System (INIS)

    2013-01-01

    This fifth chapter presents the conceptual evolution, the definition procedures, the radiological quantities themselves, the relation between them, the new operational quantities and the new quantities defined in the ICRP 60 that replaced ICRP 26 and was included in the CNEN-NN-3.01 standard of 2011

  20. 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

  1. SU-D-BRE-06: Modeling the Dosimetric Effects of Volumetric and Layer-Based Repainting Strategies in Spot Scanning Proton Treatment Plans

    International Nuclear Information System (INIS)

    Johnson, J E; Beltran, C; Herman, M G; Kruse, J J

    2014-01-01

    Purpose: To compare multiple repainting techniques as strategies for mitigating the interplay effect in free-breathing, spot scanning proton plans. Methods: An analytic routine modeled three-dimensional dose distributions of pencil-beam proton plans delivered to a moving target. The interplay effect was studied in subsequent calculations by modeling proton delivery from a clinical synchrotron based spot scanning system and respiratory target motion, patterned from surrogate breathing traces from clinical 4DCT scans and normalized to nominal 0.5 and 1 cm amplitudes. Two distinct repainting strategies were modeled. In idealized volumetric repainting, the plan is divided up and delivered multiple times successively, with each instance only delivering a fraction of the total MU. Maximum-MU repainting involves delivering a fixed number of MU per spot and repeating a given energy layer until the prescribed MU are reached. For each of 13 patient breathing traces, the dose was computed for up to four volumetric repaints and an array of maximum-MU values. Delivery strategies were inter-compared based on target coverage, dose homogeneity, and delivery time. Results: Increasing levels of repainting generally improved plan quality and reduced dosimetric variability at the expense of longer delivery time. Motion orthogonal to the scan direction yielded substantially greater dose deviations than motion parallel to the scan direction. For a fixed delivery time, maximum-MU repainting was most effective relative to idealized volumetric repainting at small maximum-MU values. For 1 cm amplitude motion orthogonal to the scan direction, the average homogeneity metric (D5 – D95)[%] of 23.4% was reduced to 7.6% with a 168 s delivery using volumetric repainting compared with 8.7% in 157.2 s for maximum-MU repainting. The associated static target homogeneity metric was 2.5%. Conclusion: Maximum-MU repainting can provide a reasonably effective alternative to volumetric repainting for

  2. Thermal quantities of 46Ti

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  3. 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.

  4. 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.

  5. Prices versus Quantities

    DEFF Research Database (Denmark)

    Hansen, Lars Gårn; Jensen, Frank

    illustrate that this result does not generalise to a search fishery, where marginal costs are allowed to depend on harvest. Hansen et al (2008) study a fishery where non-compliance with regulations is a problem. When the regulator is uncertain about non-compliance (compliance uncertainty), then landing fees......Weitzman (2002) studies the regulation of a fishery characterised by constant marginal harvest costs and shows that price regulation performs better than quantity regulation when the regulator is uncertain about the biological reproduction function (ecological uncertainty). Here, we initially...... are the preferred type of regulation, and Hansen et al (2008) find that this result does generalise to a search fishery where marginal costs depend on harvest. In this paper, we simulate a stochastic stock-recruitment model for the Danish cod fishery in the Kategat capturing both ecological and compliance...

  6. 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)

  7. 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)

  8. Strongly intensive quantities

    International Nuclear Information System (INIS)

    Gorenstein, M. I.; Gazdzicki, M.

    2011-01-01

    Analysis of fluctuations of hadron production properties in collisions of relativistic particles profits from use of measurable intensive quantities which are independent of system size variations. The first family of such quantities was proposed in 1992; another is introduced in this paper. Furthermore we present a proof of independence of volume fluctuations for quantities from both families within the framework of the grand canonical ensemble. These quantities are referred to as strongly intensive ones. Influence of conservation laws and resonance decays is also discussed.

  9. 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

  10. 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

  11. 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.

  12. Modelling of a linear accelerator VARIAN 600 C/D for dosimetric study using the Monte Carlo Method

    International Nuclear Information System (INIS)

    Cancino, Jorge Luis Batista

    2016-01-01

    Based on the high availability of low energy linear accelerators in Brazil and with the goal of developing a reliable tool for dose distribution calculations in radiotherapy; this research aims to validate a linear accelerator head model using MCNP Monte Carlo code. The Varian 600 C/D linear accelerator installed at the Hospital São João de is taken as reference. The main components of the linear accelerator head were simulated based on detailed information of the manufacturer. In order to calculate dose distribution, a water phantom with dimensions of 30 x 30 x 30 cm 3 was simulated and placed at 100 cm of source-surface distance. A monoenergetic electron beam of 6,3 MeV was considered as a source. The number of primary particles used in the simulation was 10 8 . A Phase-Space Surface was used to scoring the photon spectrum below the tungsten target. Others two were placed in the model in order to reduce computational time and improve statistical accuracy. In order to validate the developed model, the X-ray spectrum generated by Bremsstrahlung was calculated and analyzed. Furthermore, the results of percentage depth doses and beam profiles calculations were compared with available measurements. The MCNP calculations results were compared to measurement showing good agreement between them. The comparison between MCNP calculations and measurement of PDD showed reasonable coherence at build-up region. The results were in an acceptable interval of confidence at the flat region of beam profiles comparison for three different field sizes. In this work, we compared MCNP calculations to experimental data in order to validate the developed LINAC head model. The results showed a good agreement according to the recommended criteria. The developed model was validated as an accurate tool for LINAC quality control procedures. (author)

  13. 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

  14. 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

  15. Relevance of protection quantities in medical exposures

    International Nuclear Information System (INIS)

    Pradhan, A.S.

    2008-01-01

    International Commission on Radiological Protection (ICRP) continues to classify the exposures to radiation in three categories; namely 1- occupational exposure, 2- public exposure, and 3- medical exposure. Protection quantities are primarily meant for the regulatory purpose in radiological protection for controlling and limiting stochastic risks in occupational and public exposures. These are based on two basic assumptions of 1- linear no-threshold dose-effect relationship (LNT) at low doses and 2- long-term additivity of low doses. Medical exposure are predominantly delivered to individuals (patients) undergoing diagnostic examinations, interventional procedures and radiation therapy but also include individual caring for or comforting patients incurring exposure and the volunteers of biomedical medical research programmes. Radiation protection is as relevant to occupational and public exposure as to medical exposures except that the dose limits set for the formers are not applicable to medical exposure but reference levels and dose constrains are recommended for diagnostic and interventional medical procedures. In medical institutions, both the occupational and medical exposure takes place. Since the doses in diagnostic examinations are low, it has been observed that not only the protection quantities are often used in such cases but these are extended to estimate the number of cancer deaths due to such practices. One of the striking features of the new ICRP recommendations has been to elaborate the concepts of the dosimetric quantities. The limitation of protection quantities ((Effective dose, E=Σ RT D TR .W T .W R and Equivalent Dose H T =Σ RT D TR .W R ) have been brought out and this has raised a great concern and initiated debates on the use of these quantities in medical exposures. Consequently, ICRP has set a task group to provide more details and the recommendations. It has, therefore, became important to draw the attention of medical physics community

  16. 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)

  17. 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.)

  18. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  20. Dosimetric system for prolonged manned flights

    International Nuclear Information System (INIS)

    Akatov, Yu.A.; Kovalev, E.E.; Sakovich, V.A.; Deme, Sh.; Fekher, I.; Nguen, V.D.

    1991-01-01

    Comments for the All-Union state standard 25645.202-83 named Radiation safety of a spacecraft crew during space flight. Requirements for personnel dosimetric control, are given. Devices for the dosimetric control used in manned space flights nowadays are reviewed. The performance principle and structure of the FEDOR dosimetric complex under development are discussed

  1. 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

  2. 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

  3. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rupert, C S; Latarjet, R [Texas Univ., Dallas (USA)

    1978-07-01

    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.

  5. 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.

  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. 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

  8. 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

  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. Emission sources and quantities

    International Nuclear Information System (INIS)

    Heinen, B.

    1991-01-01

    The paper examines emission sources and quantities for SO 2 and NO x . Natural SO 2 is released from volcanic sources and to a much lower extent from marsh gases. In nature NO x is mainly produced in the course of the chemical and bacterial denitrification processes going on in the soil. Manmade pollutants are produced in combustion processes. The paper concentrates on manmade pollution. Aspects discussed include: mechanism of pollution development; manmade emission sources (e.g. industry, traffic, power plants and domestic sources); and emission quantities and forecasts. 11 refs., 2 figs., 5 tabs

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    Pinki Majumder

    2016-01-01

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

  14. 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.

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

    Science.gov (United States)

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

    2017-01-01

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

  16. Radiation quantities and units

    International Nuclear Information System (INIS)

    1980-01-01

    This report supersedes ICRU Report 19. Since ICRU Report 19 was published, a number of discussions have taken place between members of the Report Committee on Fundamental Quantities and Units and other workers in the field. Some of these discussions have resulted in the acceptance of certain modifications in the material set out in Report 19 and these modifications are incorporated in the current report. In addition, there has been some expansion and rearrangement of the material in the earlier report. In line, with providing more didactic material and useful source material for other ICRU reports, the general considerations in subsection 1.A of Report 19 have been expanded and placed in a separate subsection. The additional material includes discussions of four terms that are used in this document - quantity, unit, stochastic, and non-stochastic - along with a brief discussion of the mathematical formalism used in ICRU reports. As in ICRU Report 19, the definitions of quantities and units specifically designed for radiation protection (Part B) are separated from those of the general quantities (Part A). The inclusion of the index concept outlined in ICRU Report 25[4] required an extension of Part B

  17. Simulation of the Quantity, Variability, and Timing of Streamflow in the Dennys River Basin, Maine, by Use of a Precipitation-Runoff Watershed Model

    Science.gov (United States)

    Dudley, Robert W.

    2008-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Maine Department of Marine Resources Bureau of Sea Run Fisheries and Habitat, began a study in 2004 to characterize the quantity, variability, and timing of streamflow in the Dennys River. The study included a synoptic summary of historical streamflow data at a long-term streamflow gage, collecting data from an additional four short-term streamflow gages, and the development and evaluation of a distributed-parameter watershed model for the Dennys River Basin. The watershed model used in this investigation was the USGS Precipitation-Runoff Modeling System (PRMS). The Geographic Information System (GIS) Weasel was used to delineate the Dennys River Basin and subbasins and derive parameters for their physical geographic features. Calibration of the models used in this investigation involved a four-step procedure in which model output was evaluated against four calibration data sets using computed objective functions for solar radiation, potential evapotranspiration, annual and seasonal water budgets, and daily streamflows. The calibration procedure involved thousands of model runs and was carried out using the USGS software application Luca (Let us calibrate). Luca uses the Shuffled Complex Evolution (SCE) global search algorithm to calibrate the model parameters. The SCE method reliably produces satisfactory solutions for large, complex optimization problems. The primary calibration effort went into the Dennys main stem watershed model. Calibrated parameter values obtained for the Dennys main stem model were transferred to the Cathance Stream model, and a similar four-step SCE calibration procedure was performed; this effort was undertaken to determine the potential to transfer modeling information to a nearby basin in the same region. The calibrated Dennys main stem watershed model performed with Nash-Sutcliffe efficiency (NSE) statistic values for the calibration period and evaluation period of 0.79 and 0

  18. Model to calculate mass flow rate and other quantities of two-phase flow in a pipe with a densitometer, a drag disk, and a turbine meter

    International Nuclear Information System (INIS)

    Aya, I.

    1975-11-01

    The proposed model was developed at ORNL to calculate mass flow rate and other quantities of two-phase flow in a pipe when the flow is dispersed with slip between the phases. The calculational model is based on assumptions concerning the characteristics of a turbine meter and a drag disk. The model should be validated with experimental data before being used in blowdown analysis. In order to compare dispersed flow and homogeneous flow, the ratio of readings from each flow regime for each device discussed is calculated for a given mass flow rate and steam quality. The sensitivity analysis shows that the calculated flow rate of a steam-water mixture (based on the measurements of a drag disk and a gamma densitometer in which the flow is assumed to be homogeneous even if there is some slip between phases) is very close to the real flow rate in the case of dispersed flow at a low quality. As the steam quality increases at a constant slip ratio, all models are prone to overestimate. At 20 percent quality the overestimates reach 8 percent in the proposed model, 15 percent in Rouhani's model, 38 percent in homogeneous model, and 75 percent in Popper's model

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

    Directory of Open Access Journals (Sweden)

    Preeti Jawla

    2016-09-01

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

  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. Calculation of Radiation Protection Quantities and Analysis of Astronaut Orientation Dependence

    Science.gov (United States)

    Clowdsley, Martha S.; Nealy, John E.; Atwell, William; Anderson, Brooke M.; Luetke, Nathan J.; Wilson, John W.

    2006-01-01

    Health risk to astronauts due to exposure to ionizing radiation is a primary concern for exploration missions and may become the limiting factor for long duration missions. Methodologies for evaluating this risk in terms of radiation protection quantities such as dose, dose equivalent, gray equivalent, and effective dose are described. Environment models (galactic cosmic ray and solar particle event), vehicle/habitat geometry models, human geometry models, and transport codes are discussed and sample calculations for possible lunar and Mars missions are used as demonstrations. The dependence of astronaut health risk, in terms of dosimetric quantities, on astronaut orientation within a habitat is also examined. Previous work using a space station type module exposed to a proton spectrum modeling the October 1989 solar particle event showed that reorienting the astronaut within the module could change the calculated dose equivalent by a factor of two or more. Here the dose equivalent to various body tissues and the whole body effective dose due to both galactic cosmic rays and a solar particle event are calculated for a male astronaut in two different orientations, vertical and horizontal, in a representative lunar habitat. These calculations also show that the dose equivalent at some body locations resulting from a solar particle event can vary by a factor of two or more, but that the dose equivalent due to galactic cosmic rays has a much smaller (<15%) dependence on astronaut orientation.

  3. Dosimetric characterization of model Cs-1 Rev2 cesium-131 brachytherapy source in water phantoms and human tissues with MCNP5 Monte Carlo simulation

    International Nuclear Information System (INIS)

    Wang Jianhua; Zhang Hualin

    2008-01-01

    A recently developed alternative brachytherapy seed, Cs-1 Rev2 cesium-131, has begun to be used in clinical practice. The dosimetric characteristics of this source in various media, particularly in human tissues, have not been fully evaluated. The aim of this study was to calculate the dosimetric parameters for the Cs-1 Rev2 cesium-131 seed following the recommendations of the AAPM TG-43U1 report [Rivard et al., Med. Phys. 31, 633-674 (2004)] for new sources in brachytherapy applications. Dose rate constants, radial dose functions, and anisotropy functions of the source in water, Virtual Water, and relevant human soft tissues were calculated using MCNP5 Monte Carlo simulations following the TG-43U1 formalism. The results yielded dose rate constants of 1.048, 1.024, 1.041, and 1.044 cGy h -1 U -1 in water, Virtual Water, muscle, and prostate tissue, respectively. The conversion factor for this new source between water and Virtual Water was 1.02, between muscle and water was 1.006, and between prostate and water was 1.004. The authors' calculation of anisotropy functions in a Virtual Water phantom agreed closely with Murphy's measurements [Murphy et al., Med. Phys. 31, 1529-1538 (2004)]. Our calculations of the radial dose function in water and Virtual Water have good agreement with those in previous experimental and Monte Carlo studies. The TG-43U1 parameters for clinical applications in water, muscle, and prostate tissue are presented in this work

  4. Model calculations of the quantities of landfill gas, emitted from the landfill for solid domestic waste in Blagoevgrad (village of Buchino)

    International Nuclear Information System (INIS)

    Tzekova, Stefka; Ganev, Ivailo; Dimitrov, Boyan

    2009-01-01

    The biogas released from the landfills has got a noxious effect. It also creates the most serious environmental problems after the landfills closing. The gas releases actively for more than 25 years. That is why extremely high requirements for its utilization have been set today. The first step in this direction is the determination of its amounts. A prognosis for the quantities of gas released from the landfill at the village of Buchino has been made in the present report. The used mathematical model of prognosis has been adapted for the conditions in Bulgaria on the basis of the authors’ experience gained during their observations and research of a number of landfills in the country Keywords: landfill gas, biogas, RES

  5. Dosimetric evaluation program for dental radiology practices

    International Nuclear Information System (INIS)

    Gregori, B.; Milat, J.; Fernandez, J.; Micinquevich, S.; Andrieu, J.

    1992-01-01

    The preliminary results of a program undertaken to estimate the doses to patients associated with dental radiology practices in Argentine, are presented. Information collected from the search demonstrated that the Dieck and coronal techniques are the most commonly used practices, while all the examinations are performed by using a circular collimator. For both practices, the dosimetric studies were carried out on a Rando Alderson phantom. All dose measurements were made using thermoluminescent detectors LiF and Ca 2 F. In addition, a mathematical model was developed by applying the Monte Carlo method to a MIRD-V phantom. Circular and rectangular collimators were used. Absorbed dose distribution on head and neck, as well as surface dose distribution, were estimated. The comparison of the performance of both collimators shows that the use of the rectangular one allows for a dose reduction of 80%. Besides, a good correlation between the physical and mathematical models applied was found. (author)

  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. Forage quantity and quality

    Science.gov (United States)

    Jorgenson, Janet C.; Udevitz, Mark S.; Felix, Nancy A.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    The Porcupine caribou herd has traditionally used the coastal plain of the Arctic National Wildlife Refuge, Alaska, for calving. Availability of nutritious forage has been hypothesized as one of the reasons the Porcupine caribou herd migrates hundreds of kilometers to reach the coastal plain for calving (Kuropat and Bryant 1980, Russell et al. 1993).Forage quantity and quality and the chronology of snowmelt (which determines availability and phenological stages of forage) have been suggested as important habitat attributes that lead calving caribou to select one area over another (Lent 1980, White and Trudell 1980, Eastland et al. 1989). A major question when considering the impact of petroleum development is whether potential displacement of the caribou from the 1002 Area to alternate calving habitat will limit access to high quantity and quality forage.Our study had the following objectives: 1) quantify snowmelt patterns by area; 2) quantify relationships among phenology, biomass, and nutrient content of principal forage species by vegetation type; and 3) determine if traditional concentrated calving areas differ from adjacent areas with lower calving densities in terms of vegetation characteristics.

  8. 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

  9. 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.

  10. 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 ...

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. Dosimetric characterization of an electronic portal imaging device (EPID) and development of a portal dosimetry simple model; Caracterizacion dosimetrica de un dispositivo electronico de imagen portal (EPID) y desarrollo de un modelo simple de dosimetria portal

    Energy Technology Data Exchange (ETDEWEB)

    Ripol ValentIn, O.; GarcIa Romero, A.; Hernandez Vitoria, A.; Jimenez Albericio, J.; Cortes Rodicio, J.; Millan Cebrian, E.; Ruiz Manzano, P.; Canellas Anoz, M.

    2010-07-01

    The use of the Electronic Portal Imaging Devices (EPID) for the quality control of linear accelerators of electrons is increasingly extended in practice. In this work the dosimetric characteristics of an EPID OptiVue{sup TM}1000 ST were studied and a friendly and simple method for the absorbed dose calibration was suggested. This method is based on a simple mathematical model, including: an absorbed dose transformation coefficient and image lag and field shape corrections. Software tools were developed in order to process the information and the results were validated by comparing them with the measured data with ionization chambers. The studied device showed suitable characteristics for its use for EPID dosimetry and the calculated results fitted satisfactorily with the dose planes obtained with the ionization chambers. Keeping in mind the model limitations, we concluded that it is possible to start the use of the EPID for the accelerator quality control and improvements for the current model should be studied, as well as other suitable applications: e.g. the Intensity Modulated Radiation Therapy (IMRT) treatment verification procedures. (Author).

  18. 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.

  19. Dosimetric system for measurement of radioactive contaminations

    International Nuclear Information System (INIS)

    Litynski, Z.; Pienkos, J.P.; Witkowski, J.; Zadrozny, S.

    1985-01-01

    A dosimetric system for personnel dosimetry and monitoring measuring a contamination without time delay and dead time is described. The system ensures many-point measurement and minimalization of background radiation influence. 1 fig. (A.S.)

  20. 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

  1. 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

  2. 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...

  3. 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

  4. Dosimetric properties of MOS transistors

    International Nuclear Information System (INIS)

    Frank, H.; Petr, I.

    1977-01-01

    The structure of MOS transistors is described and their characteristics given. The experiments performed and data in the literature show the following dosimetric properties of MOS transistors: while for low gamma doses the transistor response to exposure is linear, it shows saturation for higher doses (exceeding 10 3 Gy in tissue). The response is independent of the energy of radiation and of the dose rate (within 10 -2 to 10 5 Gy/s). The spontaneous reduction with time of the spatial charge captured by the oxide layer (fading) is small and acceptable from the point of view of dosimetry. Curves are given of isochronous annealing of the transistors following irradiation with 137 Cs and 18 MeV electrons for different voltages during irradiation. The curves show that in MOS transistors irradiated with high-energy electrons the effect of annealing is less than in transistors irradiated with 137 Cs. In view of the requirement of using higher temperatures (approx. 400 degC) for the complete ''erasing'' of the captured charge, unsealed systems must be used for dosimetric purposes. The effect was also studied of neutron radiation, proton radiation and electron radiation on the MOS transistor structure. For MOS transistor irradiation with 14 MeV neutrons from a neutron generator the response was 4% of that for gamma radiation at the same dose equivalent. The effect of proton radiation was studied as related to the changes in MOS transistor structure during space flights. The response curve shapes are similar to those of gamma radiation curves. The effect of electron radiation on the MOS structure was studied by many authors. The experiments show that for each thickness of the SiO 2 layer an electron energy exists at which the size of the charge captured in SiO 2 is the greatest. All data show that MOS transistors are promising for radiation dosimetry. The main advantage of MOS transistors as gamma dosemeters is the ease and speed of evaluation, low sensitivity to neutron

  5. 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)

  6. 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)

  7. Dangerous quantities of radioactive material (D-values). Emergency preparedness and response. Publication date: August 2006

    International Nuclear Information System (INIS)

    2006-08-01

    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

  8. 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)

  9. 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)

  10. 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.

  11. Dosimetric effects of edema in permanent prostate seed implants: a rigorous solution

    International Nuclear Information System (INIS)

    Chen Zhe; Yue Ning; Wang Xiaohong; Roberts, Kenneth B.; Peschel, Richard; Nath, Ravinder

    2000-01-01

    Purpose: To derive a rigorous analytic solution to the dosimetric effects of prostate edema so that its impact on the conventional pre-implant and post-implant dosimetry can be studied for any given radioactive isotope and edema characteristics. Methods and Materials: The edema characteristics observed by Waterman et al (Int. J. Rad. Onc. Biol. Phys, 41:1069-1077; 1998) was used to model the time evolution of the prostate and the seed locations. The total dose to any part of prostate tissue from a seed implant was calculated analytically by parameterizing the dose fall-off from a radioactive seed as a single inverse power function of distance, with proper account of the edema-induced time evolution. The dosimetric impact of prostate edema was determined by comparing the dose calculated with full consideration of prostate edema to that calculated with the conventional dosimetry approach where the seed locations and the target volume are assumed to be stationary. Results: A rigorous analytic solution on the relative dosimetric effects of prostate edema was obtained. This solution proved explicitly that the relative dosimetric effects of edema, as found in the previous numerical studies by Yue et. al. (Int. J. Radiat. Oncol. Biol. Phys. 43, 447-454, 1999), are independent of the size and the shape of the implant target volume and are independent of the number and the locations of the seeds implanted. It also showed that the magnitude of relative dosimetric effects is independent of the location of dose evaluation point within the edematous target volume. It implies that the relative dosimetric effects of prostate edema are universal with respect to a given isotope and edema characteristic. A set of master tables for the relative dosimetric effects of edema were obtained for a wide range of edema characteristics for both 125 I and 103 Pd prostate seed implants. Conclusions: A rigorous analytic solution of the relative dosimetric effects of prostate edema has been

  12. 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.)

  13. 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)

  14. 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)

  15. 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

  16. Monte Carlo generation of dosimetric parameters for eye plaque dosimetry

    International Nuclear Information System (INIS)

    Cutajar, D.L.; Green, J.A.; Guatelli, S.; Rosenfeld, A.B.

    2010-01-01

    Full text: The Centre for Medical Radiation Physics have undertaken the dcvelopment of a quality assurance tool, using silicon pixelated detectors, for the calibration of eye plaques prior to insertion. Dosimetric software to correlate the measured and predicted dose rates has been constructed. The dosimetric parameters within the software, for both 1-125 and Ru-I 06 based eye plaques, were optimised using the Geant4 Monte Carlo toolkit. Methods For 1-125 based plaques, an novel application was developed to generate TG-43 parameters for any seed input. TG-43 parameters were generated for an Oncura model 6711 seed, with data points every millimetre up to 25 mm in the radial direction, and every 5 degrees in polar angle, and correlated to published data. For the Ru106 based plaques, an application was developed to generate dose rates about a Bebig model CCD plaque. Toroids were used to score the deposited dose, taking advantage of the cylindrical symmetry of the plaque, with radii in millimetre increments up to 25 mm, and depth from the plaque surface in millimetre increments up to 25 mm. Results TheTG43 parameters generated for the 6711 seed correlate well with published TG43 data at the given intervals, with radial dose function within 3%, and anisotropy function within 5% for angles greater than 30 degrees. The Ru-l 06 plaque data correlated well with the Bebig protocol of measurement. Conclusion Geant4 is a useful Monte Carlo tool for the generation of dosimetric data for eye plaque dosimetry. which may improve the quality assurance of eye plaque treatment. (author)

  17. 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.

  18. 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.

  19. 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

  20. ESR dosimetric properties of some biomineral materials

    International Nuclear Information System (INIS)

    Hassan, Gamal M.; Sharaf, M.A.

    2005-01-01

    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

  1. 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.

  2. WE-H-BRA-01: BEST IN PHYSICS (THERAPY): Nano-Dosimetric Kinetic Model for Variable Relative Biological Effectiveness of Proton and Ion Beams

    Energy Technology Data Exchange (ETDEWEB)

    Abolfath, R; Bronk, L; Titt, U.; Grosshans, D; Mohan, R [The University of Texas MD Anderson Cancer Center, Houston, TX (United States); Helo, Y [University College London, London (United Kingdom); Schuemann, J [Massachusetts General Hospital, Boston, MA (United States)

    2016-06-15

    Purpose: Recent clonogenic cell survival and γH2AX studies suggest proton relative biological effectiveness (RBE) may be a non-linear function of linear energy transfer (LET) in the distal edge of the Bragg peak and beyond. We sought to develop a multiscale model to account for non-linear response phenomena to aid in the optimization of intensity-modulated proton therapy. Methods: The model is based on first-principle simulations of proton track structures, including secondary ions, and an analytical derivation of the dependence on particle LET of the linear-quadratic (LQ) model parameters α and β. The derived formulas are an extension of the microdosimetric kinetic (MK) model that captures dissipative track structures and non-Poissonian distribution of DNA damage at the distal edge of the Bragg peak and beyond. Monte Carlo simulations were performed to confirm the non-linear dose-response characteristics arising from the non-Poisson distribution of initial DNA damage. Results: In contrast to low LET segments of the proton depth dose, from the beam entrance to the Bragg peak, strong deviations from non-dissipative track structures and Poisson distribution in the ionization events in the Bragg peak distal edge govern the non-linear cell response and result in the transformation α=(1+c-1 L) α-x+2(c-0 L+c-2 L^2 )(1+c-1 L) β-x and β=(1+c-1 L)^2 β-x. Here L is the charged particle LET, and c-0,c-1, and c-2 are functions of microscopic parameters and can be served as fitting parameters to the cell-survival data. In the low LET limit c-1, and c-2 are negligible hence the linear model proposed and used by Wilkins-Oelfke for the proton treatment planning system can be retrieved. The present model fits well the recent clonogenic survival data measured recently in our group in MDACC. Conclusion: The present hybrid method provides higher accuracy in calculating the RBE-weighted dose in the target and normal tissues.

  3. 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

  4. WE-H-BRA-01: BEST IN PHYSICS (THERAPY): Nano-Dosimetric Kinetic Model for Variable Relative Biological Effectiveness of Proton and Ion Beams

    International Nuclear Information System (INIS)

    Abolfath, R; Bronk, L; Titt, U.; Grosshans, D; Mohan, R; Helo, Y; Schuemann, J

    2016-01-01

    Purpose: Recent clonogenic cell survival and γH2AX studies suggest proton relative biological effectiveness (RBE) may be a non-linear function of linear energy transfer (LET) in the distal edge of the Bragg peak and beyond. We sought to develop a multiscale model to account for non-linear response phenomena to aid in the optimization of intensity-modulated proton therapy. Methods: The model is based on first-principle simulations of proton track structures, including secondary ions, and an analytical derivation of the dependence on particle LET of the linear-quadratic (LQ) model parameters α and β. The derived formulas are an extension of the microdosimetric kinetic (MK) model that captures dissipative track structures and non-Poissonian distribution of DNA damage at the distal edge of the Bragg peak and beyond. Monte Carlo simulations were performed to confirm the non-linear dose-response characteristics arising from the non-Poisson distribution of initial DNA damage. Results: In contrast to low LET segments of the proton depth dose, from the beam entrance to the Bragg peak, strong deviations from non-dissipative track structures and Poisson distribution in the ionization events in the Bragg peak distal edge govern the non-linear cell response and result in the transformation α=(1+c_1 L) α_x+2(c_0 L+c_2 L^2 )(1+c_1 L) β_x and β=(1+c_1 L)^2 β_x. Here L is the charged particle LET, and c_0,c_1, and c_2 are functions of microscopic parameters and can be served as fitting parameters to the cell-survival data. In the low LET limit c_1, and c_2 are negligible hence the linear model proposed and used by Wilkins-Oelfke for the proton treatment planning system can be retrieved. The present model fits well the recent clonogenic survival data measured recently in our group in MDACC. Conclusion: The present hybrid method provides higher accuracy in calculating the RBE-weighted dose in the target and normal tissues.

  5. Assessing the reliability of dose coefficients for exposure to radioiodine by members of the public, accounting for dosimetric and risk model uncertainties.

    Science.gov (United States)

    Puncher, M; Zhang, W; Harrison, J D; Wakeford, R

    2017-06-26

    Assessments of risk to a specific population group resulting from internal exposure to a particular radionuclide can be used to assess the reliability of the appropriate International Commission on Radiological Protection (ICRP) dose coefficients used as a radiation protection device for the specified exposure pathway. An estimate of the uncertainty on the associated risk is important for informing judgments on reliability; a derived uncertainty factor, UF, is an estimate of the 95% probable geometric difference between the best risk estimate and the nominal risk and is a useful tool for making this assessment. This paper describes the application of parameter uncertainty analysis to quantify uncertainties resulting from internal exposures to radioiodine by members of the public, specifically 1, 10 and 20-year old females from the population of England and Wales. Best estimates of thyroid cancer incidence risk (lifetime attributable risk) are calculated for ingestion or inhalation of 129 I and 131 I, accounting for uncertainties in biokinetic model and cancer risk model parameter values. These estimates are compared with the equivalent ICRP derived nominal age-, sex- and population-averaged estimates of excess thyroid cancer incidence to obtain UFs. Derived UF values for ingestion or inhalation of 131 I for 1 year, 10-year and 20-year olds are around 28, 12 and 6, respectively, when compared with ICRP Publication 103 nominal values, and 9, 7 and 14, respectively, when compared with ICRP Publication 60 values. Broadly similar results were obtained for 129 I. The uncertainties on risk estimates are largely determined by uncertainties on risk model parameters rather than uncertainties on biokinetic model parameters. An examination of the sensitivity of the results to the risk models and populations used in the calculations show variations in the central estimates of risk of a factor of around 2-3. It is assumed that the direct proportionality of excess thyroid cancer

  6. 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)

  7. Ion induced scintillation in organic solids: development of an average track model,degradation of the scintillation intensity and dosimetric applications

    International Nuclear Information System (INIS)

    Broggio, D.

    2004-12-01

    This work deals with a specific aspect of the ion-matter interaction: the scintillation induced by ions in organic materials. In the first chapter we tackle the issue in a theoretical way by proposing a method to compute the radial doses within the framework of the mean track model. We have developed a model based on the Lewis transport equation and on the Spencer distribution of the loss energy in order to take into account the transport of secondary electrons in a more realistic way. In the second chapter we study the physical mechanisms that trigger ion-induced scintillation. Ion-induced scintillation is featured by the dependence in charge number of the intensity of scintillation for ions with same energy loss and by the saturation of the scintillation efficiency for ions with high stopping-power. We have applied our model of radial doses to ion-induced scintillation. In the third chapter we study the gradual degradation of the scintillation intensity and ion-induced chemical damages. In the last chapter we propose a prototype of dosimeters based on the combination of scintillators and optical fibers that allows the real-time measurement of the dose delivered by a carbon ion beam in therapeutical use conditions. This dosimeter gives the relationship between the dose and the scintillation intensity but its accuracy is not yet sufficient for uses in radiotherapy. (A.C.)

  8. 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

  9. Quantity Estimation Of The Interactions

    International Nuclear Information System (INIS)

    Gorana, Agim; Malkaj, Partizan; Muda, Valbona

    2007-01-01

    In this paper we present some considerations about quantity estimations, regarding the range of interaction and the conservations laws in various types of interactions. Our estimations are done under classical and quantum point of view and have to do with the interaction's carriers, the radius, the influence range and the intensity of interactions

  10. 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…

  11. 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)

  12. 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.

  13. 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.

  14. Quantities used in radiological protection

    International Nuclear Information System (INIS)

    Menossi, Carlos

    2010-01-01

    The application of ICRP recommendations requires knowledge of a variety of concepts and magnitudes. Many of them are employed in other fields of science and precision in its definition reflects this wide application. In this regard, information on quantities and basic units of radiation, which exists in numerous publications, are subjects of great interest. The characteristics and radiation effects are studied by physicists, biologists and chemists mainly. However, there are basics that must be known and to be recognized by general practitioners and specialists from all branches of medicine. The information on quantities and units are used only in radiation protection, have been obtained from the reports listed on the attached bibliography. Such quantities and units contain weighting factors used to provide for different types of radiation and energies that affect the body and thus take into account the relative radio-sensitivity of different tissues. Additionally, they have added a series of data for a better understanding of the units: for example, multiples and sub-multiples, and some examples of converting the units used in radiation protection. (author) [es

  15. Quantitative analysis of patient-specific dosimetric IMRT verification

    International Nuclear Information System (INIS)

    Budgell, G J; Perrin, B A; Mott, J H L; Fairfoul, J; Mackay, R I

    2005-01-01

    Patient-specific dosimetric verification methods for IMRT treatments are variable, time-consuming and frequently qualitative, preventing evidence-based reduction in the amount of verification performed. This paper addresses some of these issues by applying a quantitative analysis parameter to the dosimetric verification procedure. Film measurements in different planes were acquired for a series of ten IMRT prostate patients, analysed using the quantitative parameter, and compared to determine the most suitable verification plane. Film and ion chamber verification results for 61 patients were analysed to determine long-term accuracy, reproducibility and stability of the planning and delivery system. The reproducibility of the measurement and analysis system was also studied. The results show that verification results are strongly dependent on the plane chosen, with the coronal plane particularly insensitive to delivery error. Unexpectedly, no correlation could be found between the levels of error in different verification planes. Longer term verification results showed consistent patterns which suggest that the amount of patient-specific verification can be safely reduced, provided proper caution is exercised: an evidence-based model for such reduction is proposed. It is concluded that dose/distance to agreement (e.g., 3%/3 mm) should be used as a criterion of acceptability. Quantitative parameters calculated for a given criterion of acceptability should be adopted in conjunction with displays that show where discrepancies occur. Planning and delivery systems which cannot meet the required standards of accuracy, reproducibility and stability to reduce verification will not be accepted by the radiotherapy community

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

    International Nuclear Information System (INIS)

    Bernard, S; Vynckier, S

    2005-01-01

    The use of low-energy photon emitters for brachytherapy applications, as in the treatment of prostate or ocular tumours, has increased significantly over the last few years. Several new seed models utilizing 103 Pd and 125 I have recently been introduced. Following the TG43U1 recommendations of the AAPM (American Association of Physicists in Medicine) (Rivard et al 2004 Med. Phys. 31 633), dose distributions around these low-energy photon emitters are characterized by the dose rate constant, the radial dose function and the anisotropy function in water. These functions and constants can be measured for each new seed in a solid phantom (i.e. solid water such as WT1) using high spatial resolution detectors such as very small thermoluminescent detectors. These experimental results in solid water must then be converted into liquid water by using Monte Carlo simulations. This paper presents the dosimetric parameters of a new palladium seed, OptiSeed TM (produced by International Brachytherapy (IBt), Seneffe, Belgium), made with a biocompatible polymeric shell and with a design that differs from the hollow titanium encapsulated seed, InterSource 103 , produced by the same company. A polymer encapsulation was chosen by the company IBt in order to reduce the quantity of radioactive material needed for a given dose rate, and to improve the symmetry of the radiation field around the seed. The necessary experimental data were obtained by measurements with LiF thermoluminescent dosimeters (1 mm 3 ) in a solid water phantom (WT1) and then converted to values in liquid water using Monte Carlo calculations (MCNP-4C). Comparison of the results with a previous study by Reniers et al (2002 Appl. Radiat. Isot. 57 805) shows very good agreement for the dose rate constant and for the radial dose function. In addition, the results also indicate an improvement in isotropy compared to a conventional titanium encapsulated seed. The relative dose (anisotropy value relative to 90 deg.) from

  17. 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

  18. 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....

  19. 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.)

  20. Dosimetric validation of the anisotropic analytical algorithm for photon dose calculation: fundamental characterization in water

    International Nuclear Information System (INIS)

    Fogliata, Antonella; Nicolini, Giorgia; Vanetti, Eugenio; Clivio, Alessandro; Cozzi, Luca

    2006-01-01

    In July 2005 a new algorithm was released by Varian Medical Systems for the Eclipse planning system and installed in our institute. It is the anisotropic analytical algorithm (AAA) for photon dose calculations, a convolution/superposition model for the first time implemented in a Varian planning system. It was therefore necessary to perform validation studies at different levels with a wide investigation approach. To validate the basic performances of the AAA, a detailed analysis of data computed by the AAA configuration algorithm was carried out and data were compared against measurements. To better appraise the performance of AAA and the capability of its configuration to tailor machine-specific characteristics, data obtained from the pencil beam convolution (PBC) algorithm implemented in Eclipse were also added in the comparison. Since the purpose of the paper is to address the basic performances of the AAA and of its configuration procedures, only data relative to measurements in water will be reported. Validation was carried out for three beams: 6 MV and 15 MV from a Clinac 2100C/D and 6 MV from a Clinac 6EX. Generally AAA calculations reproduced very well measured data, and small deviations were observed, on average, for all the quantities investigated for open and wedged fields. In particular, percentage depth-dose curves showed on average differences between calculation and measurement smaller than 1% or 1 mm, and computed profiles in the flattened region matched measurements with deviations smaller than 1% for all beams, field sizes, depths and wedges. Percentage differences in output factors were observed as small as 1% on average (with a range smaller than ±2%) for all conditions. Additional tests were carried out for enhanced dynamic wedges with results comparable to previous results. The basic dosimetric validation of the AAA was therefore considered satisfactory

  1. Thermoluminescence dosimetric characteristics of thulium doped ZnB2O4 phosphor

    International Nuclear Information System (INIS)

    Annalakshmi, O.; Jose, M.T.; Madhusoodanan, U.; Subramanian, J.; Venkatraman, B.; Amarendra, G.; Mandal, A.B.

    2014-01-01

    Polycrystalline powder samples of rare earth doped Zinc borates were synthesized by high temperature solid state diffusion technique. Dosimetric characteristics of the phosphor like thermoluminescence glow curve, TL emission spectra, dose–response, fading studies, reproducibility and reusability studies were carried out on the synthesized phosphors. Among the different rare earth doped phosphors, thulium doped zinc borate was found to have a higher sensitivity. Hence detailed dosimetric characteristics of this phosphor were carried out. It is observed that the dose–response is linear from 10 mGy to 10 3 Gy in this phosphor. EPR measurements were carried out on unirradiated, gamma irradiated and annealed phosphors to identify the defect centers responsible for thermoluminescence. A TL model is proposed based on the EPR studies in these materials. Kinetic parameters were evaluated for the dosimetric peaks using various methods. The experimental results show that this phosphor can have potential applications in radiation dosimetry applications. -- Highlights: • Polycrystalline powder samples of rare earth doped zinc borates were synthesized. • Thulium was observed to be the most efficient dopant in ZnB 2 O 4 lattice. • TL intensity of the dosimetric peak is around 20 times that of TLD-100. • Based on EPR studies a TL mechanism is proposed in zinc borate. • Deconvolution of the glow curve carried out

  2. Thermoluminescence dosimetric characteristics of thulium doped ZnB{sub 2}O{sub 4} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Annalakshmi, O. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Jose, M.T., E-mail: mtj@igcar.gov.in [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Madhusoodanan, U. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Subramanian, J. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai (India); Venkatraman, B. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Amarendra, G. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Mandal, A.B. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai (India)

    2014-02-15

    Polycrystalline powder samples of rare earth doped Zinc borates were synthesized by high temperature solid state diffusion technique. Dosimetric characteristics of the phosphor like thermoluminescence glow curve, TL emission spectra, dose–response, fading studies, reproducibility and reusability studies were carried out on the synthesized phosphors. Among the different rare earth doped phosphors, thulium doped zinc borate was found to have a higher sensitivity. Hence detailed dosimetric characteristics of this phosphor were carried out. It is observed that the dose–response is linear from 10 mGy to 10{sup 3} Gy in this phosphor. EPR measurements were carried out on unirradiated, gamma irradiated and annealed phosphors to identify the defect centers responsible for thermoluminescence. A TL model is proposed based on the EPR studies in these materials. Kinetic parameters were evaluated for the dosimetric peaks using various methods. The experimental results show that this phosphor can have potential applications in radiation dosimetry applications. -- Highlights: • Polycrystalline powder samples of rare earth doped zinc borates were synthesized. • Thulium was observed to be the most efficient dopant in ZnB{sub 2}O{sub 4} lattice. • TL intensity of the dosimetric peak is around 20 times that of TLD-100. • Based on EPR studies a TL mechanism is proposed in zinc borate. • Deconvolution of the glow curve carried out.

  3. 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

  4. 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.

  5. Hot pixel generation in active pixel sensors: dosimetric and micro-dosimetric response

    Science.gov (United States)

    Scheick, Leif; Novak, Frank

    2003-01-01

    The dosimetric response of an active pixel sensor is analyzed. heavy ions are seen to damage the pixel in much the same way as gamma radiation. The probability of a hot pixel is seen to exhibit behavior that is not typical with other microdose effects.

  6. 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

  7. Dosimetric adaptive IMRT driven by fiducial points

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-15

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

  8. Postoperative telegammatherapy of breast cancer (Dosimetric studies)

    Energy Technology Data Exchange (ETDEWEB)

    Todorov, J; Mitrov, G [Nauchno-Izsledovatelski Onkologichen Inst., Sofia (Bulgaria); Konstantinov, B; Dobrev, D [Meditsinska Akademiya, Sofia (Bulgaria). Nauchen Inst. po Rentgenologiya i Radiobiologiya

    1977-01-01

    The method employed for postoperative radiation therapy of breast cancer at the Radiologic Clinic of the Medical Academy in Sofia is described. Results are reported and discussed of dosimetric studies carried out with the T-100 on heterogeneous tissue-equivalent Rando phantom for dose distributions in the regional lymph basin and the underlying tissues and organs. The results show coincidence between calculated and measured doses in the regional lymph basin and the thoracic wall. It was demonstrated that maximal radiation loading (3600 to 5500 rad) occurs in the apical and the hilar lung area.

  9. 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

  10. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Nuttin, A

    2004-07-01

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

  12. SU-F-E-06: Dosimetric Characterization of Small Photons Beams of a Novel Linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Almonte, A; Polanco, G; Sanchez, E [Instituto Oncologico Dr. Heriberto Pieter, Santo Domingo, Distrito Nacional (Dominican Republic)

    2016-06-15

    Purpose: The aim of the present contribution was to measure the main dosimetric quantities of small fields produced by UNIQUE and evaluate its matching with the corresponding dosimetric data of one 21EX conventional linear accelerator (Varian) in operation at the same center. The second step was to evaluate comparative performance of the EDGE diode detector and the PinPoint micro-ionization chamber for dosimetry of small fields. Methods: UNIQUE is configured with MLC (120 leaves with 0.5 cm leaf width) and a single low photon energy of 6 MV. Beam data were measured with scanning EDGE diode detector (volume of 0.019 mm{sup 3}), a PinPoint micro-ionization chamber (PTW) and for larger fields (≥ 4×4cm{sup 2}) a PTW Semi flex chamber (0.125 cm{sup 3}) was used. The scanning system used was the 3D cylindrical tank manufactured by Sun Nuclear, Inc. The measurement of PDD and profiles were done at 100 cm SSD and 1.5 depth; the relative output factors were measured at 10 cm depth. Results: PDD and the profile data showed less than 1% variation between the two linear accelerators for fields size between 2×2 cm{sup 2} and 5×5cm{sup 2}. Output factor differences was less than 1% for field sizes between 3×3 cm{sup 2} and 10×10 cm{sup 2} and less of 1.5 % for fields of 1.5×1.5 cm{sup 2} and 2×2 cm{sup 2} respectively. The dmax value of the EDGE diode detector, measured from the PDD, was 8.347 mm for 0.5×0,5cm{sup 2} for UNIQUE. The performance of EDGE diode detector was comparable for all measurements in small fields. Conclusion: UNIQUE linear accelerator show similar dosimetrics characteristics as conventional 21EX Varian linear accelerator for small, medium and large field sizes.EDGE detector show good performance by measuring dosimetrics quantities in small fields typically used in IMRT and radiosurgery treatments.

  13. 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.

  14. Asymptotic conditions and conserved quantities

    International Nuclear Information System (INIS)

    Koul, R.K.

    1990-01-01

    Two problems have been investigated in this dissertation. The first one deals with the relationship between stationary space-times which are flat at null infinity and stationary space-times which are asymptotic flat at space-like infinity. It is shown that the stationary space-times which are asymptotically flat, in the Penrose sense, at null infinity, are asymptotically flat at space-like infinity in the Geroch sense and metric at space like infinity is at least C 1 . In the converse it is shown that the stationary space-times which are asymptotically flat at space like infinity, in the Beig sense, are asymptotically flat at null infinity in the Penrose sense. The second problem addressed deals with the theories of arbitrary dimensions. The theories treated are the ones which have fiber bundle structure, outside some compact region. For these theories the criterion for the choice of the background metric is specified, and the boundary condition for the initial data set (q ab , P ab ) is given in terms of the background metric. Having these boundary conditions it is shown that the symplectic structure and the constraint functionals are well defined. The conserved quantities associated with internal Killing vector fields are specified. Lastly the energy relative to a fixed background and the total energy of the theory have been given. It is also shown that the total energy of the theory is independent of the choice of the background

  15. Layer-Mean Quantities, Local Conservation Laws, and Vorticity

    International Nuclear Information System (INIS)

    Camassa, R.; Levermore, C.D.

    1997-01-01

    We derive local conservation laws for layer-mean quantities in two general settings. When applied to Euler flows, the first of these settings yields well-known local conservation laws for quantities averaged between material surfaces. The second, however, leads to new local conservation laws for quantities involving the vorticity that are averaged between arbitrary surfaces. These produce the crucial vorticity conservation laws in shallow water models that admit nonhydrostatic and noncolumnar motion. Moreover, they seem to lie outside the Hamiltonian paradigm of fluid dynamics. The formalism generalizes to skew-symmetric matrix fields; applications to electromagnetism are suggested. copyright 1997 The American Physical Society

  16. Introduction dosimetric data of cobalt-60 unit in planning new Win-PTL- 3D

    International Nuclear Information System (INIS)

    Gonzalez Perez, Yelina; Rodriguez Zayas, Michael; Perez Guevara, Adrian; Sanchez Zamora, Luis; Reyes Gonzalez, Tommy; Sola Rodriguez, Yeline; Caballero, Roberto; Cruz Marcane, Viviana

    2009-01-01

    3D planning is based on the individual and image reconstruction formation of fields, allowing better absorption of dose volume White minimizing damage to surrounding healthy tissue. During the clinical implementation of the Win-PLT software includes validation from the implementation of dosimetric acceptance tests through a series of precise experimental measurements, reflecting different clinical situations (test cases). For the commissioning characterized the photon beam Cobalt Unit 60, taking measurements with a set consisting of a phantom dosimetric automatic ionization chambers and electrometer Tandem. The measured data are used to power the TPS through WINCOM auxiliary program that lets you adjust a number of parameters to model the photon beam. This adjustment is made by comparing the PDD curves and profiles of experimental data with modeled data. The test cases performed are in compliance with the requirements proposed in the geometric of the AAPM TG55. The modeling of beam dosimetry data was successful, since the discrepancies were within the criteria TRS-430. The cases involved events where points near the edge of the field and in the presence of blocking a discrepancy outside the tolerance, suggesting not to use these items for purposes of limitation. Win TPS-PLT is suitable for clinical use with the photon beam Cobalt Unit 60, backed by the reliability that dropped on the results of beam modeling and verification of dosimetric calculations. (Author)

  17. 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

  18. 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.

  19. 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)

  20. Dosimetric management during a criticality accident

    International Nuclear Information System (INIS)

    Lebaron-Jacobs, L.; Fottorino, R.; Racine, Y.; Miele, A.; Barbry, F.; Briot, F.; Distinguin, S.; Le Goff, J.P.; Berard, P.; Boisson, P.; Cavadore, D.; Lecoix, G.; Persico, M.H.; Rongier, E.; Challeton-De Vathaire, C.; Medioni, R.; Voisin, P.; Exmelin, L.; Flury-Herard, A.; Gaillard-Lecanu, E.; Lemaire, G.; Gonin, M.; Riasse, C.

    2008-01-01

    A working group from health occupational and clinical biochemistry services on French sites has issued essential data sheets on the guidelines to follow in managing the victims of a criticality accident. Since the priority of the medical management after a criticality accident is to assess the dose and the distribution of dose, some dosimetric investigations have been selected in order to provide a prompt response and to anticipate the final dose reconstruction. Comparison exercises between clinical biochemistry laboratories on French sites were carried out to confirm that each laboratory maintained the required operational methods for hair treatment and the appropriate equipment for 32 P activity in hair and 24 Na activity in blood measurements, and to demonstrate its ability to rapidly provide neutron dose estimates after a criticality accident. As a result, a relation has been assessed to estimate the dose and the distribution of dose according to the neutron spectrum following a criticality accident. (authors)

  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. ARDENT to develop advanced dosimetric techniques

    CERN Document Server

    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...

  3. 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)

  4. The Need for New Dosimetric Approach in CT Dosimetry

    International Nuclear Information System (INIS)

    Ben-Shlomo, A.; Iacobovici, E.

    2004-01-01

    Three decades after the invention of the first CT in 1972, it became a major tool in diagnostic radiology. The use of CT for various applications is getting wider every year. The quantity of CT procedures performed in Israel every year is estimated as 500,000. About 10% of those are pediatric procedures, for children under age 10. CT procedures increase is estimated at 5-10 % per annum. In spite the fact that CT contributes to about 1/8 of the total number of diagnostic X-ray procedures in Israel, the CT collective dosage is about 40% of the total collective dosage in the said procedures (about 3,500 Man*Sv per year). Medical radiation dosage is the first contributor to population dosage, resulting from artificial radiation sources. Diagnostic X-ray radiation dosage is the first contributor to medical radiation dose (including radiation dose from diagnostic X-ray, nuclear medicine and radiotherapy with exclusion of the target organ dose). Among medical X-ray different applications, CT procedure is the first cause to radiation dose of the population according to X-ray diagnostic procedures. The above facts emphasize the need to focus on CT in order to reduce the medical collective dose of the public. Several dosimetric units have appeared in recent years in order to comply with the need for CT Dosimetry. The CTDI Unit that served so well during the first CT years is no longer sufficient, as is, for modern instruments. This basic unit has become a complex concept that covers new units: CTDI W , CTDI VOL , CTDI 100 , MSAD and DLP. The search for a simple way to apply these units in order to calculate effective dosage during CT examinations is not straightforward. Modern equipment is simultaneously using 4 and 16 slices. Manufacturers are endeavoring to develop the next generation equipment with 256 slices used simultaneously (expected on the market in the next 1-2 years). This situation sets technology one step forward regarding the dosimetry methods used for organ

  5. Study on the neutron dosimetric characteristics of Tissue Equivalent Proportional Counter

    Energy Technology Data Exchange (ETDEWEB)

    Nunomiya, T.; Kim, E.; Kurosawa, T.; Taniguchi, S.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Tsujimura, N.; Momose, T.; Shinohara, K. [Japan Nuclear Cycle Development Inst., Environment and Safety Division, Tokai Works, Tokai, Ibaraki (Japan)

    1999-03-01

    The neutron dosimetric characteristics of TEPC (Tissue Equivalent Proportional Counter) has been investigated under a cooperative study between Tohoku University and JNC since 1997. This TEPC is a spherical, large volume, single-wire proportional counter (the model LETSW-5, manufactured by Far West Technology, Inc.) and filled with a tissue equivalent gas in a spherical detector of the A-150 tissue equivalent plastic. The TEPC can measure the spectra of absorbed dose in LET and easily estimate the tissue equivalent dose to neutron. This report summarizes the dosimetric characteristics of TEPC to the monoenergetic neutrons with energy from 8 keV to 15 MeV. It is found that TEPC can estimate the ambient dose equivalent, H*(10), with an accuracy from 0.9 to 2 to the neutron above 0.25 MeV and TEPC has a good counting efficiency enough to measure neutron doses with low dose rate at the stray neutron fields. (author)

  6. Realisation of dosimetric studies for working stations with a risk of exposure to ionizing radiations. Practical guide

    International Nuclear Information System (INIS)

    Donadille, L.; Queinnec, F.; Bottollier-Depois, J.F.; Clairand, I.; Rehel, J.L.; Deligne, J.M.; Aubert, B.; Jourdain, J.R.; Rannou, A.

    2007-01-01

    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, classify the workers into different categories and the workplaces into different areas. 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. (author)

  7. Realisation of dosimetric studies for workplaces with a risk of exposure to ionizing radiations (version 2). Practical guide

    International Nuclear Information System (INIS)

    Donadille, L.; Rehel, J.L.; Deligne, J.M.; Queinnec, F.; Aubert, B.; Bottollier-Depois, J.F.; Clairand, I.; Jourdain, J.R.; Rannou, A.

    2010-01-01

    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, classify the workers into different categories and the workplaces into different areas. 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. (authors)

  8. 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)

  9. Computerized dosimetric system for studying radiation fields of afterloading apparatus

    International Nuclear Information System (INIS)

    Andryushin, O.S.; Gorshkov, M.I.

    1988-01-01

    Works on designing a computerized dosimetric scanner (CODOS) for studying radiation fields of remote therapeutic apparatus, providing dosimetric data input from semiconductor transducers and ionization chambers directly into the computer memory were carried out. The basic problems were to provide reproducibility and accuracy of the initial dosimetric data, formation of the data bank on LUEhV-15M1 accelerator bremsstrahlung and electron radiation fields. An extra problem was to provide isodose curves for manual scheduling of radiotherapy. The 15 VUMS-28-025 complex based on Elektronika-60 computer was chosen as a host computer, photodiodes were used as a semiconductor detector, the 70108 rod chamber and VA-J-18 dosemeters were used as an ionization chamber. The results of studies with the CODOS system have been shown that it meets the dosimetric requirements for therapeutic apparatus

  10. 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

  11. 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.

  12. Dose rate constants for new dose quantities

    International Nuclear Information System (INIS)

    Tschurlovits, M.; Daverda, G.; Leitner, A.

    1992-01-01

    Conceptual changes and new quantities made is necessary to reassess dose rate quantities. Calculations of the dose rate constant were done for air kerma, ambient dose equivalent and directional dose equivalent. The number of radionuclides is more than 200. The threshold energy is selected as 20 keV for the dose equivalent constants. The dose rate constant for the photon equivalent dose as used mainly in German speaking countries as a temporary quantity is also included. (Author)

  13. 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

  14. Radiation process control, study and acceptance of dosimetric methods

    International Nuclear Information System (INIS)

    Radak, B.B.

    1984-01-01

    The methods of primary dosimetric standardization and the calibration of dosimetric monitors suitable for radiation process control were outlined in the form of a logical pattern in which they are in current use on industrial scale in Yugoslavia. The reliability of the process control of industrial sterilization of medical supplies for the last four years was discussed. The preparatory works for the intermittent use of electron beams in cable industry were described. (author)

  15. The new operational quantities for radiation protection

    International Nuclear Information System (INIS)

    Kellerer, A.M.

    1985-01-01

    Philosophies and quantities for radiation protection have often been subjected to changes, and some of the developments are traced which ultimately led to recent proposals by ICRU. Development in the past has largely been towards clarification and generalisation of definitions. The present changes, however, reflect a more fundamental issue, the transition from the limitation system to the assessment system in radiation protection. The index quantities were suitable tools to ascertain compliance with the limitation system of radiation protection. The new quantities proposed by ICRU are suitable estimators for effective dose equivalent, which is an essential quantity in the assessment system of radiation protection. A synopsis of the definitions is given. (author)

  16. QUANTITY AND QUALITY IN ACCOUNTING

    Directory of Open Access Journals (Sweden)

    Horia Cristea

    2016-12-01

    Full Text Available The present paper is a synthesis of the scopes of accounting in understanding the economic processes and transactions from the quantitative and qualitative point of view. The economic life is a continuous set of choices and decisions (of maintaining, developing, correcting based on the information supplied by the accounting. The input information that are processed can be incorrect, processed with correct models and the outputs can be correct, incorrectly processed and with incorrect results.

  17. 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.

  18. Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources.

    Science.gov (United States)

    Ghorbani, Mahdi; Mehrpouyan, Mohammad; Davenport, David; Ahmadi Moghaddas, Toktam

    2016-06-01

    The aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric parameters. Different photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources. MCNPX code was used to simulate 125I, 103Pd, 169Yb, and 192Ir brachytherapy sources. Air kerma strength per activity, dose rate constant, radial dose function, and two dimensional (2D) anisotropy functions were calculated and isodose curves were plotted for three different photon energy spectra. The references for photon energy spectra were: published papers, Lawrence Berkeley National Laboratory (LBNL), and National Nuclear Data Center (NNDC). The data calculated by these photon energy spectra were compared. Dose rate constant values showed a maximum difference of 24.07% for 103Pd source with different photon energy spectra. Radial dose function values based on different spectra were relatively the same. 2D anisotropy function values showed minor differences in most of distances and angles. There was not any detectable difference between the isodose contours. Dosimetric parameters obtained with different photon spectra were relatively the same, however it is suggested that more accurate and updated photon energy spectra be used in Monte Carlo simulations. This would allow for calculation of reliable dosimetric data for source modeling and calculation in brachytherapy treatment planning systems.

  19. Medical linear accelerator mounted mini-beam collimator: design, fabrication and dosimetric characterization.

    Science.gov (United States)

    Cranmer-Sargison, G; Crewson, C; Davis, W M; Sidhu, N P; Kundapur, V

    2015-09-07

    The goal of this work was to design, build and experimentally characterize a linear accelerator mounted mini-beam collimator for use at a nominal 6 MV beam energy. Monte Carlo simulation was used in the design and dosimetric characterization of a compact mini-beam collimator assembly mounted to a medical linear accelerator. After fabrication, experimental mini-beam dose profiles and central axis relative output were measured and the results used to validate the simulation data. The simulation data was then used to establish traceability back to an established dosimetric code of practice. The Monte Carlo simulation work revealed that changes in collimator blade width have a greater influence on the valley-to-peak dose ratio than do changes in blade height. There was good agreement between the modeled and measured profile data, with the exception of small differences on either side of the central peak dose. These differences were found to be systematic across all depths and result from limitations associated with the collimator fabrication. Experimental mini-beam relative output and simulation data agreed to better than ± 2.0%, which is well within the level of uncertainty required for dosimetric traceability of non-standard field geometries. A mini-beam collimator has now been designed, built and experimentally characterized for use with a commercial linear accelerator operated at a nominal 6 MV beam energy.

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

    International Nuclear Information System (INIS)

    Jormada, Tiago S.

    2013-01-01

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

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

    African Journals Online (AJOL)

    This research study was conducted in order to investigate Continuing Professional Development (CPD) in the South African quantity surveying profession. The study further aimed to establish the reasons why some quantity surveyors do not acquire the required CPD hours and face losing their professional registration with ...

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

    African Journals Online (AJOL)

    1991-01-01

    Jan 1, 1991 ... The research established that quantity surveyors regarded handing in their CPD ... Surveying, Walter Sisulu University, PO Box 1421, East London, 5200, South Africa. ... Keywords: Continuing professional development, quantity surveying, perception .... In spite of this opportunity enshrined in the Act, the.

  3. 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...

  4. 30 CFR 75.325 - Air quantity.

    Science.gov (United States)

    2010-07-01

    ... the exposure of miners. (i) A ventilating air quantity that is less than what is required by paragraph... results of sampling that demonstrate that the lesser air quantity will maintain continuous compliance with applicable TLV ®'s. (j) If during sampling required by § 70.1900(c) of this subchapter the ventilating air is...

  5. 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

  6. Method and means for determining heat quantities

    Energy Technology Data Exchange (ETDEWEB)

    Waasdorp, G G; de Jong, J J; Bijl, A

    1965-08-24

    To determine the quantity of potential heat W that has flowed past a certain point in a certain time, the velocity of the combustible Q, the temperature T, and the specific gravity YDTU are measured, and these values are transmitted to a computer which automatically calculates the quantity: ..pi..EQUATION/sup -/ in which delta T is the difference between the combustible temperature T and a reference temperature, and in which the relation f(YDTU, delta T) represents the heat of combustion as a function of the quantities YDTU and delta T and possibly other properties of the combustible. Alternatively the quantity: ..pi..EQUATION/sup -/ may be measured; here the quantities have the same meaning as above.

  7. 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)

  8. Dosimetric feature of natural biotite mineral

    International Nuclear Information System (INIS)

    Kalita, J.M.; Wary, G.

    2015-01-01

    A thermoluminescence (TL) study relevant to radiation dosimetry has been carried out for X-ray irradiated biotite mineral under un-annealed and different annealed (473, 573, 673 and 773 K) conditions. Some significant variations in dosimetric characteristics have been observed with annealing treatment. Due to generation of an additional shallow trap level at depth 0.78 eV in 673 and 773 K annealed samples, the dose response is found to improve. For the 773 K annealed sample, a linear dose response has been observed from 10 to 1100 mGy. The fading is ∼13 % within 5 d after irradiation and onward it reduces to 7 % up to 60 d. Reproducibility of this (773 K) sample is excellent. After 10 recycles the coefficient of variations in the results for the 60, 180 and 1000 mGy dose-irradiated samples are found to be 0.97, 1.31 and 1.03 %, respectively. The potential use of biotite as a natural X-ray dosemeter is discussed. (authors)

  9. 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

  10. 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.

  11. 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.

  12. 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)

  13. The TL and OSL study of hydroxyapatites for dosimetric applications

    International Nuclear Information System (INIS)

    Alencar, Marcus A. Vallim de

    2009-01-01

    The hydroxyapatite, the principal mineral component of the bone and tooth enamel, is one of the dosimetric materials that has distinguished itself in the high dose and accidents dosimetry, as well as in the dating, for the Electron Paramagnetic Resonance (EPR) technique. For this reason, the hydroxyapatite could also be used as Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) dosimeter in the dosimetry of high doses and accidents, and also in the archaeological and geological dating. This work presents a brief study of the TL and OSL behaviour of the B type synthetic carbonated hydroxyapatite, observing the possibility to use this material in TL and OSL dosimetry. The samples were irradiated to a dose of 100 Gy and 1000 Gy, and the TL and OSL measurements were obtained by the RISOE TL/OSL reader, model TL/OSL-DA-15B. The first results demonstrate the presence of three peaks in the TL glow curve in the temperatures of 100 deg C, 150 deg C and 280 deg C. The synthetic carbonated hydroxyapatite also presents an OSL signal when the sample is stimulated with blue light and a small OSL signal for stimulation with infrared light (IR). These results indicate the possibility of this synthetic carbonated hydroxyapatite to be used as dose indicator material using the TL and OSL techniques. (author)

  14. 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)

  15. Dosimetric Analysis of Radiation-induced Gastric Bleeding

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-01

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

  16. Dosimetric Analysis of Radiation-induced Gastric Bleeding

    International Nuclear Information System (INIS)

    Feng, Mary; Normolle, Daniel; Pan, Charlie C.; Dawson, Laura A.; Amarnath, Sudha; Ensminger, William D.; Lawrence, Theodore S.; Ten Haken, Randall K.

    2012-01-01

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

  17. 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

  18. Workplace stress experienced by quantity surveyors

    African Journals Online (AJOL)

    Paul (P.A.) Bowen, Department of Construction Economics and Management,. University of Cape Town, Private ..... Explore workplace stress levels among quantity surveyors in the developing nation of ...... London: Free. Association Books.

  19. 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)

  20. '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)

  1. The Radiometric Measurement Quantity for SAR Images

    OpenAIRE

    Döring, Björn J.; Schwerdt, Marco

    2013-01-01

    A Synthetic Aperture Radar (SAR) system measures among other quantities the terrain radar reflectivity. After image calibration, the pixel intensities are commonly expressed in terms of radar cross sections (for point targets) or as backscatter coefficients (for distributed targets), which are directly related. This paper argues that pixel intensities are not generally proportional to radar cross section or derived physical quantities. The paper further proposes to replace the inaccurate term...

  2. Average Transverse Momentum Quantities Approaching the Lightfront

    OpenAIRE

    Boer, Daniel

    2015-01-01

    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 transverse momenta, which conveys little information about the transverse momentum distributions of quarks and gluons inside hadrons. TMD factorization naturally suggests alternative definitions of su...

  3. A conserved quantity in thin body dynamics

    Science.gov (United States)

    Hanna, J. A.; Pendar, H.

    2016-02-01

    Thin, solid bodies with metric symmetries admit a restricted form of reparameterization invariance. Their dynamical equilibria include motions with both rigid and flowing aspects. On such configurations, a quantity is conserved along the intrinsic coordinate corresponding to the symmetry. As an example of its utility, this conserved quantity is combined with linear and angular momentum currents to construct solutions for the equilibria of a rotating, flowing string, for which it is akin to Bernoulli's constant.

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

    Directory of Open Access Journals (Sweden)

    Frank eDomahs

    2012-01-01

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

  5. Utilization of a photon transport code to investigate radiation therapy treatment planning quantities and techniques

    International Nuclear Information System (INIS)

    Palta, J.R.

    1981-01-01

    A versatile computer program MORSE, based on neutron and photon transport theory has been utilzed to investigate radiation therapy treatment planning quantities and techniques. A multi-energy group representation of transport equation provides a concise approach in utilizing Monte Carlo numerical techniques to multiple radiation therapy treatment planning problems. Central axis total and scattered dose distributions for homogeneous and inhomogeneous water phantoms are calculated and the correction factor for lung and bone inhomogeneities are also evaluated. Results show that Monte Carlo calculations based on multi-energy group tansport theory predict the depth dose distributions that are in good agreement with available experimental data. Central axis depth dose distributions for a bremsstrahlung spectrum from a linear accelerator is also calculated to exhibit the versatility of the computer program in handling multiple radiation therapy problems. A novel approach is undertaken to study the dosimetric properties of brachytherapy sources

  6. Dosimetric essay in dental radiology; Experiencia dosimetrica en radiologia odontologica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Salaberry, M [Ministerio de Industria, Energia y Mineria, Montevideo (Uruguay). Direccion Nacional de Tecnologia Nuclear; Dato Carfagna, A; Rodriguez Dorgia, R [Universidad de la Republica, Facultad de Odontologia , Montevideo (Uruguay)

    1999-12-31

    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

  7. Dosimetric control of radiotherapy treatments by Monte Carlo simulation of transmitted portal dose image

    International Nuclear Information System (INIS)

    Badel, Jean-Noel

    2009-01-01

    This research thesis addresses the dosimetric control of radiotherapy treatments by using amorphous silicon digital portal imagery. In a first part, the author reports the analysis of the dosimetric abilities of the imager (iViewGT) which is used in the radiotherapy department. The stability of the imager response on a short and on a long term has been studied. A relationship between the image grey level and the dose has been established for a reference irradiation field. The influence of irradiation parameters on the grey level variation with respect to the dose has been assessed. The obtained results show the possibility to use this system for dosimetry provided that a precise calibration is performed while taking the most influencing irradiation parameters into account, i.e. photon beam nominal energy, field size, and patient thickness. The author reports the development of a Monte Carlo simulation to model the imager response. It models the accelerator head by a generalized source point. Space and energy distributions of photons are calculated. This modelling can also be applied to the calculation of dose distribution within a patient, or to study physical interactions in the accelerator head. Then, the author explores a new approach to dose portal image prediction within the frame of an in vivo dosimetric control. He computes the image transmitted through the patient by Monte Carlo simulation, and measures the portal image of the irradiation field without the patient. Validation experiments are reported, and problems to be solved are highlighted (computation time, improvement of the collimator simulation) [fr

  8. 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

  9. Critical review of the current radiation protection quantities and units

    International Nuclear Information System (INIS)

    Sabol, J.

    1998-01-01

    Examples exist in dosimetry and radiation protection where primary attention was focused on the unit rather than the corresponding quantity. Another difficulty arises from the fact that quantities in this field cannot be considered as pure physical quantities, they are rather biophysical quantities. There are too many quantities (e. g. 17 quantities based on the dose equivalent), with differences in numerical values of 'similar' quantities, not always satisfactory approximations of virtually unmeasurable quantities by measurable quantities, inconsistency in definitions and interpretations of quantities of some international expert bodies, and problems of weighting and conversion factors. (M.D.)

  10. TL dosimetric properties BAM:EU

    International Nuclear Information System (INIS)

    Rao, Bellam N.; Murthy, K.V.R.; Subba Rao, B.; Saiprasad, A.S.

    2011-01-01

    In phosphor area today top priority is the replacement of the high performance but very expensive rare earth activated phosphors with cheaper materials. This essentially means replacing the rare earth ions with transition metal ions or post transition ions. Now a day's phosphors are used in various fields. After World War II, the advances in the optical spectroscopy of solids, especially those of transition metals ions help to evolve research on phosphor and solid state luminescence. In 1960 efficient rare earth activated phosphors were developed for use in color TV (Tb 3+ green, Eu 3+ red, and Dy 3+ yellow). In 1970 tricolor lamp was introduced blue emission from Ce 3+ + Tb 3+ pair was used in tricolor lamps. At present combination of halo phosphor and tri-band phosphor blend is used in many lamp as a compromise between performance, phosphor cost and the lamp making Cost. Thermo luminescence of 0.5 Gy X-ray irradiated BAM.Eu has been studied. The irradiated phosphor has been studied for its TL dosimetric properties one week after irradiation and after 100 weeks of storage. Interesting TL results are reported in the present paper. Heating rate used in the present experiment is 6.6 deg C/Sec. The following two figures are on TL recorded 100 weeks after irradiation and TL recorded after 235 weeks of storage. Before storage for 100 weeks the TL glow curve with a hump around 180 deg C followed by a peak at 273 deg C. After storage for 100 weeks the TL pattern changes entirely. i.e. the composite TL peak structure emerged as two well resolved peaks and with slightly higher TL peak temperatures at 215 deg C and 300 deg C. Normally after storage for 100 weeks the peak at 190 deg C reduces in its intensity or disappears in some cases, instead of that the peak appears at 215 deg C as well resolved peak and its intensity is almost comparable to that of 300 deg C peak. Since the TL phenomenon observed is interesting the two well resolved, isolated, high intensity peaks

  11. 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

  12. 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.

  13. 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)

  14. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-07-01

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

  16. Management of small quantities of radioactive waste

    International Nuclear Information System (INIS)

    1998-09-01

    The main objective of this publication is to provide practical guidance primarily to developing Member States on the predisposal management of small quantities of radioactive waste arising from hospitals, laboratories, industries, institutions, research reactors and research centres.The publication covers the management of liquid, solid and gaseous radioactive wastes at the users' premises and gives general guidance on procedures at a centralized waste management facility. Predisposal management of radioactive waste includes handling, treatment, conditioning, storage and transportation. This publication provides information and guidance on the following topics: national waste management framework; origin and characteristics of radioactive waste arising from users generating small quantities of waste; radioactive waste management concepts appropriate for small quantities; local waste management; the documentation and approval necessary for the consignment of waste to a centralized waste management facility; centralized waste management; exemption of radionuclides from the regulatory body; transportation; environmental monitoring; quality assurance for the whole predisposal process; regional co-operation aspects

  17. A conserved quantity in thin body dynamics

    International Nuclear Information System (INIS)

    Hanna, J.A.; Pendar, H.

    2016-01-01

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

  18. A conserved quantity in thin body dynamics

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-15

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

  19. Dosimetric Effects of Air Pockets Around High-Dose Rate Brachytherapy Vaginal Cylinders

    International Nuclear Information System (INIS)

    Richardson, Susan; Palaniswaamy, Geethpriya; Grigsby, Perry W.

    2010-01-01

    Purpose: Most physicians use a single-channel vaginal cylinder for postoperative endometrial cancer brachytherapy. Recent published data have identified air pockets between the vaginal cylinders and the vaginal mucosa. The purpose of this research was to evaluate the incidence, size, and dosimetric effects of these air pockets. Methods and Materials: 25 patients receiving postoperative vaginal cuff brachytherapy with a high-dose rate vaginal cylinders were enrolled in this prospective data collection study. Patients were treated with 6 fractions of 200 to 400 cGy per fraction prescribed at 5 mm depth. Computed tomography simulation for brachytherapy treatment planning was performed for each fraction. The quantity, volume, and dosimetric impact of the air pockets surrounding the cylinder were quantified. Results: In 25 patients, a total of 90 air pockets were present in 150 procedures (60%). Five patients had no air pockets present during any of their treatments. The average number of air pockets per patient was 3.6, with the average total air pocket volume being 0.34 cm 3 (range, 0.01-1.32 cm 3 ). The average dose reduction to the vaginal mucosa at the air pocket was 27% (range, 9-58%). Ten patients had no air pockets on their first fraction but air pockets occurred in subsequent fractions. Conclusion: Air pockets between high-dose rate vaginal cylinder applicators and the vaginal mucosa are present in the majority of fractions of therapy, and their presence varies from patient to patient and fraction to fraction. The existence of air pockets results in reduced radiation dose to the vaginal mucosa.

  20. Characterizing Interfraction Variations and Their Dosimetric Effects in Prostate Cancer Radiotherapy

    International Nuclear Information System (INIS)

    Peng Cheng; Ahunbay, Ergun; Chen Guangpei; Anderson, Savannah; Lawton, Colleen; Li, X. Allen

    2011-01-01

    Purpose: To quantitatively characterize the interfraction variations and their dosimetric effects in radiotherapy for prostate cancer. Methods and Materials: A total of 486 daily computed tomography (CT) sets acquired for 20 prostate cancer patients treated with daily CT-guided repositioning using a linear accelerator and CT-on-rail combination were analyzed. The prostate, rectum, and bladder, delineated on each daily CT data set, were compared with those from the planning CT scan. Several quantities, including Dice's coefficient and the maximal overlapping rate, were used to characterize the interfraction variations. The delivered dose was reconstructed by applying the original plan to the daily CT scan with consideration of proper repositioning. Results: The mean prostate Dice's coefficient and maximal overlapping rate after bony registration was 69.7% ± 13.8% (standard deviation) and 85.6% ± 7.8% (standard deviation), respectively. The daily delivered dose distributions were generally inferior to the planned dose distribution for target coverage and/or normal structure sparing. For example, for approximately 5% of the treatment fractions, the prostate volume receiving 100% of the prescription dose decreased dramatically (15-20%) compared with its planned value. The magnitudes of the interfraction variations and their dosimetric effects indicated that, statistically, current standard repositioning using prostate alignment might be adequate for two-thirds of the fractions, but for the rest of the fractions, better on-line correction strategies, such as on-line replanning, are needed. Conclusion: Different adaptive correction schemes for prostatic interfraction changes can be used according to the anatomic changes, as quantified by the organ displacement and deformation parameters. On-line replanning is needed for approximately one-third of the treatment fractions.

  1. Experimental and theoretical determination of dosimetric characteristics of IsoAid ADVANTAGETM125I brachytherapy source

    International Nuclear Information System (INIS)

    Meigooni, Ali S.; Hayes, Joshua L.; Zhang Hualin; Sowards, Keith

    2002-01-01

    125 I brachytherapy sources are being used for interstitial implants in tumor sites such as the prostate. Recently, the ADVANTAGE TM 125 I, Model IAI-125, source became commercially available for interstitial brachytherapy treatment. Dosimetric characteristics (dose rate constant, radial dose function, and anisotropy function) of this source were experimentally and theoretically determined, following the AAPM Task Group 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 phantom using LiF thermoluminescent dosimeters. The theoretical calculations were performed in both Solid Water TM and water using the PTRAN Monte Carlo code. The results indicated that a dose rate constant of the new source in water was 0.98±0.03 cGy h -1 U -1 . The radial dose function of the new source was measured in Solid Water TM and calculated both in water and Solid Water TM at distances up to 10.0 cm. The anisotropy function, F(r,θ), of the new source was measured and calculated in Solid Water TM at distances of 2 cm, 3 cm, 5 cm, and 7 cm and also was calculated in water at distances ranging from 1 cm to 7 cm from the source. From the anisotropy function, the anisotropy factors and anisotropy constant were derived. The anisotropy constant of the ADVANTAGE TM 125 I source in water was found to be 0.97±0.03. The dosimetric characteristics of this new source compared favorably with those from the Amersham Health Model 6711 source. Complete dosimetric parameters of the new source are presented in this paper

  2. 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

  3. 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.)

  4. 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)

  5. 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)

  6. 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.

  7. 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)

  8. 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

  9. 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...

  10. 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…

  11. Symmetries and conserved quantities in geodesic motion

    International Nuclear Information System (INIS)

    Hojman, S.; Nunez, L.; Patino, A.; Rago, H.

    1986-01-01

    Recently obtained results linking several constants of motion to one (non-Noetherian) symmetry to the problem of geodesic motion in Riemannian space-times are applied. The construction of conserved quantities in geodesic motion as well as the deduction of geometrical statements about Riemannian space-times are achieved

  12. 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)

  13. 16 CFR 500.25 - Net quantity, average quantity, permitted variations.

    Science.gov (United States)

    2010-01-01

    ... good distribution practice and which unavoidably result in change of weight or mass or measure. (c... good packaging practice: Provided, that such variations shall not be permitted to such extent that the... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Net quantity, average quantity, permitted...

  14. Dosimetric effects of an air cavity for the SAVI partial breast irradiation applicator

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Susan L.; Pino, Ramiro [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Department of Radiation Oncology, Methodist Hospital, Houston, Texas 77030 and Texas Cancer Clinic, San Antonio, Texas 78240 (United States)

    2010-08-15

    Purpose: To investigate the dosimetric effect of the air inside the SAVI partial breast irradiation device. Methods: The authors have investigated how the air inside the SAVI partial breast irradiation device changes the delivered dose from the homogeneously calculated dose. Measurements were made with the device filled with air and water to allow comparison to a homogenous dose calculation done by the treatment planning system. Measurements were made with an ion chamber, TLDs, and film. Monte Carlo (MC) simulations of the experiment were done using the EGSnrc suite. The MC model was validated by comparing the water-filled calculations to those from a commercial treatment planning system. Results: The magnitude of the dosimetric effect depends on the size of the cavity, the arrangement of sources, and the relative dwell times. For a simple case using only the central catheter of the largest device, MC results indicate that the dose at the prescription point 1 cm away from the air-water boundary is about 9% higher than the homogeneous calculation. Independent measurements in a water phantom with a similar air cavity gave comparable results. MC simulation of a realistic multidwell position plan showed discrepancies of about 5% on average at the prescription point for the largest device. Conclusions: The dosimetric effect of the air cavity is in the range of 3%-9%. Unless a heterogeneous dose calculation algorithm is used, users should be aware of the possibility of small treatment planning dose errors for this device and make modifications to the treatment delivery, if necessary.

  15. 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

  16. 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

  17. Dosimetric behavior of thermoluminescent dosimeters at low doses in diagnostic radiology

    International Nuclear Information System (INIS)

    Del Sol F, S.; Garcia S, R.; Guzman M, J.; Sanchez G, D.; Rivera M, T.; Ramirez R, G.; Gaona, E.

    2015-10-01

    Thermoluminescent (Tl) characteristics of TLD-100, LiF:Mg,Cu,P, and CaSO 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 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 4 : Dy). (Author)

  18. Dosimetric effects of rotational output variation and x-ray target degradation on helical tomotherapy plans

    International Nuclear Information System (INIS)

    Staton, Robert J.; Langen, Katja M.; Kupelian, Patrick A.; Meeks, Sanford L.

    2009-01-01

    In this study, two potential sources of IMRT delivery error have been identified for helical tomotherapy delivery using the HiART system (TomoTherapy, Inc., Madison, WI): Rotational output variation and target degradation. The HiArt system is known to have output variation, typically about ±2%, due to the absence of a dose servo system. On the HiArt system, x-ray target replacement is required approximately every 10-12 months due to target degradation. Near the end of target life, the target thins and causes a decrease in the beam energy and a softening of the beam profile at the lateral edges of the beam. The purpose of this study is to evaluate the dosimetric effects of rotational output variation and target degradation by modeling their effects and incorporating them into recalculated treatment plans for three clinical scenarios: Head and neck, partial breast, and prostate. Models were created to emulate both potential sources of error. For output variation, a model was created using a sine function to match the amplitude (±2%), frequency, and phase of the measured rotational output variation data. A second model with a hypothetical variation of ±7% was also created to represent the largest variation that could exist without violating the allowable dose window in the delivery system. A measured beam profile near the end of target life was used to create a modified beam profile model for the target degradation. These models were then incorporated into the treatment plan by modifying the leaf opening times in the delivery sinogram. A new beam model was also created to mimic the change in beam energy seen near the end of target life. The plans were then calculated using a research version of the PLANNED ADAPTIVE treatment planning software from TomoTherapy, Inc. Three plans were evaluated in this study: Head and neck, partial breast, and prostate. The D 50 of organs at risk, the D 95 for planning target volumes (PTVs), and the local dose difference were used to

  19. Solvation quantities from a COSMO-RS equation of state

    International Nuclear Information System (INIS)

    Panayiotou, C.; Tsivintzelis, I.; Aslanidou, D.; Hatzimanikatis, V.

    2015-01-01

    Highlights: • Extension of the successful COSMO-RS model to an equation-of-state model. • Two scaling constants, obtained from atom-specific contributions. • Overall estimation of the solvation quantities and contributions. - Abstract: This work focuses on the extension of the successful COSMO-RS model of mixtures into an equation-of-state model of fluids and its application for the estimation of solvation/hydration quantities of a variety of chemical substances. These quantities include free-energies, enthalpies and entropies of hydration as well as the separate contributions to each of them. Emphasis is given on the estimation of contributions from the conformational changes of solutes upon solvation and the associated restructuring of solvent in its immediate neighborhood. COSMO-RS is a quantum-mechanics based group/segment contribution model in which the Quasi-Chemical (QC) approach is used for the description of the non-random distribution of interacting segments in the system. Thus, the equation-of-state development is done through such a QC framework. The new model will not need any adjustable parameters for the strong specific interactions, such as hydrogen bonds, since they will be provided by the quantum-mechanics based cosmo-files – a key feature of COSMO-RS model. It will need, however, one volumetric and one energy parameter per fluid, which are scaling constants or molecular descriptors of the fluid and are obtained from rather easily available data such as densities, boiling points, vapor pressures, heats of vaporization or second virial coefficients. The performance and the potential of the new equation-of-state model to become a fully predictive model are critically discussed

  20. 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...

  1. Comparison of dosimetric methods for virtual wedge analysis

    International Nuclear Information System (INIS)

    Bailey, M.; Nelson, V.; Collins, O.; West, M.; Holloway, L.; Rajapaske, S.; Arts, J.; Varas, J.; Cho, G.; Hill, R.

    2004-01-01

    Full text: The Siemens Virtual Wedge (Concord, USA) creates wedged beam profile by moving a single collimator jaw across the specified field size whilst varying the dose rate and jaw speed for use in the delivery of radiotherapy treatments. The measurement of the dosimetric characteristics of the Siemens Virtual Wedge poses significant challenges to medical physicists. This study investigates several different methods for measuring and analysing the virtual wedge for data collection for treatment planning systems and ongoing quality assurance. The beam profiles of the Virtual Wedge (VW) were compared using several different dosimetric methods. Open field profiles were measured with Kodak X-Omat V (Rochester, NY, USA) radiographic film and compared with measurements made using the Sun Nuclear Profiler with a Motorized Drive Assembly (MDA) (Melbourne, FL, USA) and the Scanditronix Wellhofer CC13 ionisation chamber and 24 ion Chamber Array (CA24) (Schwarzenbruck, Germany). The resolution of each dosimetric method for open field profiles was determined. The Virtual Wedge profiles were measured with radiographic film the Profiler and the Scanditronix Wellhofer CA 24 ion Chamber Array at 5 different depths. The ease of setup, time taken, analysis and accuracy of measurement were all evaluated to determine the method that would be both appropriate and practical for routine quality assurance of the Virtual Wedge. The open field profiles agreed within ±2% or 2mm for all dosimetric methods. The accuracy of the Profiler and CA24 are limited to half of the step size selected for each of these detectors. For the VW measurements a step size of 2mm was selected for the Profiler and the CA24. The VW profiles for all dosimetric methods agreed within ±2% or 2mm for the main wedged section of the profile. The toe and heel ends of the wedges showed the significant discrepancies dependent upon the dosimetry method used, up to 7% for the toe end with the CA24. The dosimetry of the

  2. Radiation quantities and units. ICRU report 33

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    This report supersedes ICRU Report 19. Since ICRU Report 19 was published, a number of discussions have taken place between members of the Report Committee on Fundamental Quantities and Units and other workers in the field. Some of these discussions have resulted in the acceptance of certain modifications in the material set out in Report 19 and these modifications are incorporated in the current report. In addition, there has been some expansion and rearrangement of the material in the earlier report. It is recommended that energy state be inserted into the definition of activity and that the word transformation be replaced by transition. These modifications have now been incorporated into the current definition. Helpful comments on the previous quantities and units report have resulted in clarification of several points in the present Report. In line with providing more didactic material and useful source material for other ICRU reports, the general considerations in subsection I.A of Report 19 have been expanded and placed in a separate subsection. The additional material includes discussions of four terms that are used in this document - quantity, unit, stochastic, and non-stochastic - along with a brief discussion of the mathematical formalism used in ICRU reports. 11 refs., 4 tabs

  3. Quantity discrimination in wolves (Canis lupus

    Directory of Open Access Journals (Sweden)

    Ewelina eUtrata

    2012-11-01

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

  4. 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

  5. Radiometric and dosimetric characteristics of HgI2 detectors

    International Nuclear Information System (INIS)

    Zaletin, V.M.; Krivozubov, O.V.; Torlin, M.A.; Fomin, V.I.

    1988-01-01

    The characteristics of HgI 2 detectors in x-ray and gamma detection in applications to radiometric and dosimetric monitoring and as portable instruments for such purposes was considered. Blocks with mosaic and sandwich structures were prepared and tested against each other and, for comparative purposes, against CdTe detectors for relative sensitivities at various gamma-quanta energies. Sensitivity dependencies on gamma radiation energy were plotted for the detector materials and structures as were current dependencies on the dose rate of x rays. Results indicated that the mercury iodide detectors could be used in radiometric and dosimetric measurements at gamma quantum energies up to and in excess of 1000 KeV

  6. 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.

  7. Influence of lucite phantoms on calibration of dosimetric pens

    International Nuclear Information System (INIS)

    Oliveira, E.C.; Xavier, M.; Caldas, L.E.V.

    1992-01-01

    Dosimetrical pens were studied for the answer repetition and were tested in gamma radiation fields ( 60 Co and 137 Cs) in air and in front of a lucite phantom, obtaining a backscattering contribution. The medium backscattering factors were 1,053 and 1,108 for respectively 60 Co and 137 Cs. The pens were placed behind the phantom for verifying the radiation attenuation. (C.G.C.)

  8. 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.

  9. 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.

  10. 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.

  11. 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…

  12. Use of a dosimetric system using a SMT phototransistor in the measurement for some dosimetric parameters in conventional radiotherapy

    International Nuclear Information System (INIS)

    Silva, J.O. da; Magalhaes, C.M.S. de; Santos, L.A.P.

    2008-01-01

    For monitoring the delivered dose in the patient undergoing a cancer treatment with high-energy ionizing radiation beams is necessary to use appropriate dosimeters for the beam control quality and if it is possible, to obtain the dose information during the treatment. For this, semiconductor-based devices are used because of their high spatial resolution and to be easy to handle in spite of the ionization chambers. Nowadays the bipolar phototransistors are being proposed as ionizing radiation detectors for presenting, beyond these characteristics, the signal amplification factor (gain). So, the aim of this work is to present the use of a dosimetric system using a SMT phototransistor in the measurement for some dosimetric parameters in conventional radiotherapy: the field factor and the off-axis ratio. The phototransistors readings were compared with ones obtained from a PTW 23343 Markus chamber, under the same conditions. (author)

  13. Neutron dosimetric measurements in shuttle and MIR

    International Nuclear Information System (INIS)

    Reitz, G.

    2001-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-02-01

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

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

    International Nuclear Information System (INIS)

    Senthi, Sashendra; Gill, Suki S.; Haworth, Annette; Kron, Tomas; Cramb, Jim; Rolfo, Aldo; Thomas, Jessica; Duchesne, Gillian M.; Hamilton, Christopher H.; Joon, Daryl Lim; Bowden, Patrick; Foroudi, Farshad

    2012-01-01

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

  16. A design of ambient dose equivalent dosimeter and its dosimetric performance

    International Nuclear Information System (INIS)

    Zhao Shian; Ou Xiangming; Li Kaibao

    1997-01-01

    Objective: To design an ambient dose equivalent dosimeter with digital display for radiation protection, which is based on the definition of the new operational radiation quantity for environmental monitoring-ambient dose equivalent recommended by the International Commission on Radiation Units and Measurements (ICRU) Report 39. Methods: Considering the energy response of the instrument, the inner wall of ionizing chamber is coated with gum graphite added with a bit of metal powder. Results: Using this chamber, measurement of H * (10) for photon radiation with unknown spectrum distribution is possible in the energy range from 47 keV to 230 keV with an uncertainty of better than 5%. The configuration, technology and dosimetric performance of the chamber and automatic functions of the reader are presented. Conclusion: The ambient dose equivalent dosimeter can be used as not only a working reference dosimeter, but also a field dosimeter for radiation protection because the readings are expressed directly in ambient dose equivalent and averaged automatically in the period of measurement. Also, its power is supplied by battery for the portable purpose and the readings are displayed on the screen with light-background for dim field

  17. 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

  18. 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)

  19. 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.

  20. 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 ...

  1. 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)

  2. 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...

  3. 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...

  4. Internal Dosimetric Calculations for Occupationally Exposed Workers

    International Nuclear Information System (INIS)

    Hussein, M.T.; Farag, H.I.

    2005-01-01

    The Internal radiation dosimetry calculations are very important to estimate the benefit and the risk of radiation in nuclear medicine field for both patient and worker. MIRD scheme and ICRP model have valid methods in this type of calculations. In this work, a new program called WIRDST the Workers Internal Radiation Dosimetry Simulation for Thyroid gland has been built up by using the Monte Carlo (MC) method to simulate the internal exposure of sodium iodide by inhalation for workers. The working conditions have been taken as the same as found in the hot laboratory of nuclear medicine unit in the National Cancer Institute in Cairo University. The point source equivalent model as a parameterization equation has developed newly by using the fitting model of MC method for uniform distribution of radioactive sodium iodide in the thyroid gland. This model is used for the first time in this type of calculation, and then applied on 3 D coordinates of mathematical geometry for the adult phantom of the reference man. The latest parameters (anatomical data and inhalation metabolic data) of ICRP pamphlets and recommendations have been used in this purpose. Moreover, the latest scheme for iodine decay mode and the latest geometry model for thyroid gland are used also. The results showed that the specific effective energy and the effective dose decrease from the thyroid gland to the nearest organs then decrease gradually until terminated in the organs that have large distance from the thyroid. The Annual Limit of Intake (ALI) has been calculated for a wide range of thyroid uptake (5%, 15%, 25%, 35%, 45%, and 55%) in addition to change of the working time order per week in one year. The results showed that the critical point of intake limits are decreased when the thyroid uptake is increased and/or the number of working time in the hot laboratory per week is increased

  5. Calculation of skin dose due to beta contamination using the new quantity of the ICRP 116: the local skin dose

    International Nuclear Information System (INIS)

    Bourgois, L.; Menard, S.; Comte, N.

    2017-01-01

    Values of the new protection quantity Local Skin Dose 'LSD', introduced by the International Commission on Radiological Protection (ICRP) Publication 116, were calculated for 134 β - or β + emitting radionuclides, using the Monte Carlo code MCNP6. Two types of source geometry are considered: a point source and disc-type surface contamination (the source is placed in contact with the skin). This new protection quantity is compared with the operational quantity H2 (0.07, 0 deg.), leading us to conclude that, in accordance with the rules of the ICRP, the operational quantity over-estimates the protection quantity to a reasonable extent, except in very rare cases for very low average beta energies. Thus, with the new skin model described in ICRP 116, there are no longer any major differences between the operational quantities and protection quantities estimated with the skin model described in ICRP 74. (authors)

  6. 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

  7. 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

  8. 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

  9. 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.

  10. Variations of influence quantities in industrial irradiators and their effect on dosimetry performance

    International Nuclear Information System (INIS)

    Chu, R.D.H.

    1999-01-01

    Many environmental factors, including irradiation temperature, post-irradiation storage temperature, dose rate, relative humidity, oxygen content and the energy spectrum may affect the response of dosimetry systems used in industrial radiation processing. Although the effects of individual influence quantities have been extensively studied, the variations of these influence quantities in production irradiators and the complex relationships between the effects of different influence quantities make it difficult to assess the overall effect on the measurement uncertainty. In the development of new dosimetry systems it is important to know the effect of each influence quantity and developers of new dosimetry systems should perform studies over a wide range of irradiation conditions. Analysis parameters and manufacturing specifications should be chosen to minimize the effect of influence quantities in the environments where the dosimeters will be used. Because of possible relationships between different influence quantities, care must be taken to ensure that the response function determined in the calibration of the dosimetry system is applicable for the conditions in which the dosimeters will be used. Reference standard dosimetry systems which have been thoroughly studied and have known relationships between dose response and influence quantities should be used to verify the calibration of routine dosimetry systems under the actual conditions of use. Better understanding of the variations in influence quantities in industrial irradiators may be obtained by modeling or direct measurements and may provide improvements in the calibration of routine dosimetry system and reduction of the overall measurement uncertainty. (author)

  11. 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)

  12. A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Son, Jaeman; Baek, Taesung; Lee, Boram; Shin, Dongho; Park, Sung Yong; Park, Jeonghoon; Lim, Young Kyung; Lee, Se Byeong; Kim, Jooyoung; Yoon, Myonggeun

    2015-01-01

    This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used. Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film, a diode array (Mapcheck), an ion chamber array (MatriXX) and an electronic portal imaging device (EPID) for patient-specific QA. The measured doses from the four dosimetric tools were compared with the dose calculated by the treatment planning system. The passing rates of the four dosimetric tools were calculated using the gamma index method, using as criteria a dose difference of 3% and a distance-to-agreement of 3 mm. The QA results based on Mapcheck, MatriXX and EPID showed good agreement, with average passing rates of 99.61%, 99.04% and 99.29%, respectively. However, the average passing rate based on film measurement was significantly lower, 95.88%. The average uncertainty (1 standard deviation) of passing rates for 6 intensity modulated fields was around 0.31 for film measurement, larger than those of the other three dosimetric tools. QA results and consistencies depend on the choice of dosimetric tool. Universal passing rates should depend on the normalization or inter-comparisons of dosimetric tools if more than one dosimetric tool is used for patient specific QA

  13. A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy.

    Science.gov (United States)

    Son, Jaeman; Baek, Taesung; Lee, Boram; Shin, Dongho; Park, Sung Yong; Park, Jeonghoon; Lim, Young Kyung; Lee, Se Byeong; Kim, Jooyoung; Yoon, Myonggeun

    2015-09-01

    This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used. Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film, a diode array (Mapcheck), an ion chamber array (MatriXX) and an electronic portal imaging device (EPID) for patient-specific QA. The measured doses from the four dosimetric tools were compared with the dose calculated by the treatment planning system. The passing rates of the four dosimetric tools were calculated using the gamma index method, using as criteria a dose difference of 3% and a distance-to-agreement of 3 mm. The QA results based on Mapcheck, MatriXX and EPID showed good agreement, with average passing rates of 99.61%, 99.04% and 99.29%, respectively. However, the average passing rate based on film measurement was significantly lower, 95.88%. The average uncertainty (1 standard deviation) of passing rates for 6 intensity modulated fields was around 0.31 for film measurement, larger than those of the other three dosimetric tools. QA results and consistencies depend on the choice of dosimetric tool. Universal passing rates should depend on the normalization or inter-comparisons of dosimetric tools if more than one dosimetric tool is used for patient specific QA.

  14. 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.

  15. 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

  16. Dosimetric measurement of the disintegration rate of fission products

    International Nuclear Information System (INIS)

    Solymosi, J.; Nagy, L.G.; Zagyvai, P.

    1992-01-01

    Investigations on the disintegration rate of fission products of 238 U and 239 Pu are presented. The intensity of the β-and γ-radiation of fission products were measured continously in an interval of 1-1300 hours following the fission, offering the possibility for determining the general and specific characteristics of the individual fission products. A universal measuring procedure was elaborated for the rapid in situ determination of the dosimetric features of fission products, which is suitable for the accurate evaluation and prediction of external absorbed dose even in case of fission products of various origin and unknown composition. (author) 6 refs.; 7 figs.; 1 tab

  17. On the set up of a thermoluminescent dosimetric system

    International Nuclear Information System (INIS)

    Furetta, C.

    2000-01-01

    In this work are treated the following features: Introduction to the thermoluminescent dosimetric systems, their prerequisites, Initialisation procedure, Batch homogeneity, Procedure for batch homogeneity (IEC), Reference and field dosimeters, Thermal treatments and its general considerations, as well as its initialisation treatment, erasing treatment or standard annealing (also called pre-irradiation annealing), post-irradiation or pre-readout annealing. Also is presented the performance of the annealing study, with its suggested procedures such as: a first and second procedures. Finally, it is showed about experimental data of the annealing treatments and its diagrams. (Author)

  18. 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.)

  19. 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)

  20. Dosimetry in radiodiagnosis. Individual irradiation card. Dosimetric application of electrets

    International Nuclear Information System (INIS)

    Lisbona, Albert.

    1981-09-01

    This study deals with a radiodiagnosis dosimetry, and contains two parts. First of all, the combination between a dosimetric data acquisition from an ionization chamber and a micro-computer allows the realization of individual irradiation card for a well established examination. The method is extensible to almost totality of radiological examinations. The second part describes the following of an original work about the application of electrets in radiodiagnosis dosimetry. At least a theorical study is shown; it takes account of different involving phenomena and allows a starting interpretation of experimental results [fr

  1. 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)

  2. Method of accounting and suppressing the instability of dosimetric information

    International Nuclear Information System (INIS)

    Fejtek, Ya.

    1977-01-01

    To account for dosimetric information instability differential and integral correcting factors are proposed. The differential factor converts signals of dosimeters irradiated during short but different periods of time into equivalent signals related to a certain period of time. The factor excludes the effect of signal instability in the case of short exposures. The integral factor represents a generalization of the differential one for prolonged exposures. The statistical integral factor is derived. An example of processing experimental data using the analytical method developed is presented. The method is pointed out to have been introduced in the state personal dosimetry service in Czechoslovakia [ru

  3. 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.

  4. Dosimetric implications of the infiltrated injection

    International Nuclear Information System (INIS)

    Castronovo, F.P.; McKusick, K.A.; Strauss, H.W.

    1984-01-01

    Following inadvertent infiltration of a radiopharmaceutical, there is variable and uncertain uptake in target tissue. Concomitantly, there is also a concern for the radiation dose to the infiltrated site. This investigation determined the clearance and radiation burdens from various radiopharmaceutical infiltrates in a rat model. Nine separate sites were studied for: Tc-99m microspheres; Tc-99m MDP; Ga-67 citrate; and Tl-201 chloride. Following sc injection on the shaven posteriors of anesthetized adult male Sprague-Dawley rats, gamma camera and computer data were collected up to 24 hours. The resulting data were expressed semilogarithmically as the mean (N = 9) of the ''% retained at site'' as a f(time) after injection. Nonparticulate agents showed a tri-exponential release pattern from each site, whereas the microspheres remained for an extended period of time. Using these pharma-cokinetic curves, the % remaining at each site for various times, and rems/mCi per lcc infiltrate was determined

  5. 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.

  6. 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)

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

    International Nuclear Information System (INIS)

    Mandigo, R.L.

    1996-01-01

    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.''

  8. Discounting of quantity surveying fees in South Africa

    African Journals Online (AJOL)

    by clients have forced Quantity Surveying firms into competition with ... Furthermore, 43% of consulting engineering firms were discounting their fees at a rate of .... Quantity. Surveying services are also offered in the fields of dispute resolution,.

  9. 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)

  10. Sensitivity of postplanning target and OAR coverage estimates to dosimetric margin distribution sampling parameters.

    Science.gov (United States)

    Xu, Huijun; Gordon, J James; Siebers, Jeffrey V

    2011-02-01

    A dosimetric margin (DM) is the margin in a specified direction between a structure and a specified isodose surface, corresponding to a prescription or tolerance dose. The dosimetric margin distribution (DMD) is the distribution of DMs over all directions. Given a geometric uncertainty model, representing inter- or intrafraction setup uncertainties or internal organ motion, the DMD can be used to calculate coverage Q, which is the probability that a realized target or organ-at-risk (OAR) dose metric D, exceeds the corresponding prescription or tolerance dose. Postplanning coverage evaluation quantifies the percentage of uncertainties for which target and OAR structures meet their intended dose constraints. The goal of the present work is to evaluate coverage probabilities for 28 prostate treatment plans to determine DMD sampling parameters that ensure adequate accuracy for postplanning coverage estimates. Normally distributed interfraction setup uncertainties were applied to 28 plans for localized prostate cancer, with prescribed dose of 79.2 Gy and 10 mm clinical target volume to planning target volume (CTV-to-PTV) margins. Using angular or isotropic sampling techniques, dosimetric margins were determined for the CTV, bladder and rectum, assuming shift invariance of the dose distribution. For angular sampling, DMDs were sampled at fixed angular intervals w (e.g., w = 1 degree, 2 degrees, 5 degrees, 10 degrees, 20 degrees). Isotropic samples were uniformly distributed on the unit sphere resulting in variable angular increments, but were calculated for the same number of sampling directions as angular DMDs, and accordingly characterized by the effective angular increment omega eff. In each direction, the DM was calculated by moving the structure in radial steps of size delta (=0.1, 0.2, 0.5, 1 mm) until the specified isodose was crossed. Coverage estimation accuracy deltaQ was quantified as a function of the sampling parameters omega or omega eff and delta. The

  11. Rainwater in Egypt: quantity, distribution and harvesting

    Directory of Open Access Journals (Sweden)

    H.I. ABDEL-SHAFY

    2010-11-01

    Full Text Available Egypt has limited water resources, and it will be under water stress within the year 2030. Therefore, Egypt should consider the natural and non-conventional water resources to overcome such problem. Rain harvesting is one solution; but not all; particularly on the north coast by the Mediterranean Sea and the Red sea. In this paper, the rainwater issue is reviewed and discussed in terms of the quantities and distribution at different selected areas in Egypt. The amount of rain falls at different location in Egypt was collected for a period of 16 months. The data indicated that rainfall in Egypt is very scarce, with an annual average of 12 mm and ranges from 0 mm/year in the desert to 200 mm/year in the north coastal region. The maximum total amount of rain does not exceed 1.8 billion m3per year. However, the average annual amount of rainfall water that is effectively utilized for agriculture purposes is estimated to be 1 billion m3. Harvesting pilot plant was constructed and implemented in Alexandria directly on the Mediterranean Sea. The harvested rain was used for irrigation and treated for drinking. It was, therefore, recommended to develop sustainable catchments at appropriate locations in the rain-fed areas at the north coast as well as cost effective grafting of the indigenous technologies with the innovative techniques.

  12. 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...

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

    African Journals Online (AJOL)

    African Journal of Food, Agriculture, Nutrition and Development ... determining the right quantity of milt that can be used to fertilize certain quantity of eggs. ... quantity of milt used for artificial reproduction in fish significantly affect water quality used ... is the major organic substance that supplies the spermatozoa with energy.

  14. 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)

  15. 7 CFR 61.102 - Determination of quantity index.

    Science.gov (United States)

    2010-01-01

    ... the quantity index shall equal four times percentage of oil plus six times percentage of ammonia, plus 5. (b) For American Pima cottonseed the quantity index shall equal four times percentage of oil... 7 Agriculture 3 2010-01-01 2010-01-01 false Determination of quantity index. 61.102 Section 61.102...

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

    Directory of Open Access Journals (Sweden)

    Sandra Transchel

    2008-05-01

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

  17. 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.

  18. Dosimetric characteristics of muscovite mineral studied under different annealing conditions

    International Nuclear Information System (INIS)

    Kalita, J M; Wary, G

    2015-01-01

    The annealing effect on the thermoluminescence (TL) characteristics of x-ray irradiated muscovite mineral relevant to dosimetry has been studied. For un-annealed and 473 K annealed samples an isolated TL peak has been observed at around 347 K; however, annealing at 573, 673 and 773 K two composite peaks have been recorded at around 347 and 408 K. Kinetic analysis reveals that there is a trap level at a depth of 0.71 eV, and due to annealing at 573 K (or above), a new trap level generates at 1.23 eV. The dosimetric characteristics, such as dose response, fading and reproducibility, have been studied in detail for all types of samples. The highest linear dose response has been observed from 10 to 2000 mGy in the 773 K annealed sample. Due to generation of the deep trap level, fading is found to reduce significantly just after annealing above 573 K. Reproducibility analysis shows that after 10 cycles of reuse the coefficient of variations in the results for 60, 180 and 1000 mGy dose irradiated 773 K annealed samples are found to be 1.78%, 1.37% and 1.58%, respectively. These analyses demand that after proper annealing muscovite shows important dosimetric features that are essentially required for a thermoluminescence dosimeter (TLD). (paper)

  19. Quality control of dosimetric systems using thermoluminescent crystals

    International Nuclear Information System (INIS)

    Mahecha, L.; Plazas, M. C.; Machado, M.; Perea, M. D.

    2006-01-01

    To achieve an optimal tumoral control to prostate cancer in early and locally advanced stages, it is necessary to increase the dose with a low mobility probability at the vesicle an rectal level. This is achieved through conformal radiotherapy. The Instituto Nacional de Cancerologia uses this technique, but two questions arise from the medical-physicists and medical radio-oncologist: In accordance with clinical protocols, the conformal radiotherapy delivers a low dose to the adjacent healthy tissues. What experimental method exists that can prove with certainly the veracity of this affirmation?. And, Do the dosimetric simulation system calculate suitable the dose for each tissues?. Through thermoluminescent dosimetry and the use of a physical simulator,we measured the absorbed dose at the target volume and the adjacent tissues using conformal and conventional radiotherapy. We proved that organs such as the rectum and bladder, receiver a minor dose in conformal radiotherapy, hence reducing their mobility probability. In addition, the readings from the thermoluminescent dosimeters and the doses calculated by the ECLIPSE dosimetric system were compared, concluding that the patient's prescribed dose is effectively delivered as recommended by the quality control program in radiotherapy. (Author)

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

    Science.gov (United States)

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

    2009-02-01

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

  1. Dosimetric verification of the intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Zou Huawei; Jia Mingxuan; Wu Rong; Xiao Fuda; Dong Xiaoqi

    2004-01-01

    Objective: To discuss the methods of the dosimetric verification in the intensity-modulated radiation therapy (IMRT) and insure correct execution of the IMRT planning in the clinical practice. Methods: The CMSFOCUS9200 inverse planning system was used to provide optimized 5-field IMRT treatment plans for the patients. A phantom was made from true water-equivalent material. The doses of the interesting points and isodose distributions of the interesting planes in the phantom were calculated using patients' treatment plan. The phantom was placed on the couch of the accelerator and was irradiated using the phantom's treatment planning data. The doses of interesting points were measured using a 0.23 cc chamber and the isodose distributions of interesting planes were measured using RIT 113 film dosimetry system in the phantom. The results were compared with those from calculation in planning system for verification. Results: The doses and isodose distributions measured by the chamber and the film were consistent with those predicted by the planning. The error between the measured dose and calculated dose in the interesting points was less than 3%. Conclusion: The dosimetric verification of IMRT is a reliable measure in the course of its implementation. (authors)

  2. The effects of quantity and depth of processing on children's time perception.

    Science.gov (United States)

    Arlin, M

    1986-08-01

    Two experiments were conducted to investigate the effects of quantity and depth of processing on children's time perception. These experiments tested the appropriateness of two adult time-perception models (attentional and storage size) for younger ages. Children were given stimulus sets of equal time which varied by level of processing (deep/shallow) and quantity (list length). In the first experiment, 28 children in Grade 6 reproduced presentation times of various quantities of pictures under deep (living/nonliving categorization) or shallow (repeating label) conditions. Students also compared pairs of durations. In the second experiment, 128 children in Grades K, 2, 4, and 6 reproduced presentation times under similar conditions with three or six pictures and with deep or shallow processing requirements. Deep processing led to decreased estimation of time. Higher quantity led to increased estimation of time. Comparative judgments were influenced by quantity. The interaction between age and depth of processing was significant. Older children were more affected by depth differences than were younger children. Results were interpreted as supporting different aspects of each adult model as explanations of children's time perception. The processing effect supported the attentional model and the quantity effect supported the storage size model.

  3. 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...... quality module can handle conservative pollutants, first order depletion and non-linear reactions. For demonstration purposes, we model pollutant releases as biochemical oxygen demand (BOD) and use the Streeter-Phelps equation for oxygen deficit to compute the resulting min-imum dissolved oxygen...

  4. 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

  5. A dosimetric intercomparison of brachytherapy facilities in Ireland, Scotland and the North of England

    International Nuclear Information System (INIS)

    Heeney, Conor; McClean, Brendan; Kelly, Colin

    2005-01-01

    Background and purpose: A dosimetric intercomparison of brachytherapy remote afterloading units in Ireland, Scotland and the North of England has been carried out involving 9 radiotherapy centres, and sampling 5 HDR and 6 LDR units. Materials and methods: Absolute calibrations have been performed in air on both HDR and LDR sources. The results are expressed in terms of a ratio of local to calibrated value. Frequency distributions were obtained for the multi-source LDR units by individually measuring each source. Using these distributions the effect of non-uniform source strength on the dose rate at Manchester point A was assessed for a typical clinical brachytherapy insertion for carcinoma of the cervix. Both frequency and dose rate distribution curves were modeled using normal statistics and characterised in terms of the mean (μ) and standard deviation (σ). Results: Evaluation of the HDR units indicated a mean ratio of 1.008 (±0.01) while for LDR the mean ratio was 0.997 (±0.02). The LDR frequency distributions demonstrated a variation of σ values extending from 1.4 to 3.0% of μ. It was shown that this non-uniformity in source strength introduced an uncertainty in the treatment planning process of between 0.8 and 1.8% when compared to the assumption of uniform source strength. Conclusions: The results of this intercomparison indicate dosimetric consistency between centres for both LDR and HDR units. The distribution of LDR source strengths were within expected limits and the resultant dose rate distributions were considered clinically acceptable

  6. 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)

  7. 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.

  8. 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)

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. Fractionated stereotactic radiotherapy: A method to evaluate geometric and dosimetric uncertainties using radiochromic films

    Energy Technology Data Exchange (ETDEWEB)

    Coscia, Gianluca; Vaccara, Elena; Corvisiero, Roberta; Cavazzani, Paolo; Ruggieri, Filippo Grillo; Taccini, Gianni [S. C. Fisica Sanitaria, E.O. Ospedali Galliera di Genova, Via Alessandro Volta, 8 16128 Genova (Italy); S. C. Radioterapia, E.O. Ospedali Galliera di Genova, Via Alessandro Volta, 8 16128 Genova (Italy); S. C. Fisica Sanitaria, E.O. Ospedali Galliera di Genova, Via Alessandro Volta, 8 16128 Genova (Italy)

    2009-07-15

    In the authors' hospital, stereotactic radiotherapy treatments are performed with a Varian Clinac 600C equipped with a BrainLAB m3 micro-multileaf-collimator generally using the dynamic conformal arc technique. Patient immobilization during the treatment is achieved with a fixation mask supplied by BrainLAB, made with two reinforced thermoplastic sheets fitting the patient's head. With this work the authors propose a method to evaluate treatment geometric accuracy and, consequently, to determine the amount of the margin to keep in the CTV-PTV expansion during the treatment planning. The reproducibility of the isocenter position was tested by simulating a complete treatment on the anthropomorphic phantom Alderson Rando, inserting in between two phantom slices a high sensitivity Gafchromic EBT film, properly prepared and calibrated, and repeating several treatment sessions, each time removing the fixing mask and replacing the film inside the phantom. The comparison between the dose distributions measured on films and computed by TPS, after a precise image registration procedure performed by a commercial piece of software (FILMQA, 3cognition LLC (Division of ISP), Wayne, NJ), allowed the authors to measure the repositioning errors, obtaining about 0.5 mm in case of central spherical PTV and about 1.5 mm in case of peripheral irregular PTV. Moreover, an evaluation of the errors in the registration procedure was performed, giving negligible values with respect to the quantities to be measured. The above intrinsic two-dimensional estimate of treatment accuracy has to be increased for the error in the third dimension, but the 2 mm margin the authors generally use for the CTV-PTV expansion seems adequate anyway. Using the same EBT films, a dosimetric verification of the treatment planning system was done. Measured dose values are larger or smaller than the nominal ones depending on geometric irradiation conditions, but, in the authors' experimental

  14. Fractionated stereotactic radiotherapy: A method to evaluate geometric and dosimetric uncertainties using radiochromic films

    International Nuclear Information System (INIS)

    Coscia, Gianluca; Vaccara, Elena; Corvisiero, Roberta; Cavazzani, Paolo; Ruggieri, Filippo Grillo; Taccini, Gianni

    2009-01-01

    In the authors' hospital, stereotactic radiotherapy treatments are performed with a Varian Clinac 600C equipped with a BrainLAB m3 micro-multileaf-collimator generally using the dynamic conformal arc technique. Patient immobilization during the treatment is achieved with a fixation mask supplied by BrainLAB, made with two reinforced thermoplastic sheets fitting the patient's head. With this work the authors propose a method to evaluate treatment geometric accuracy and, consequently, to determine the amount of the margin to keep in the CTV-PTV expansion during the treatment planning. The reproducibility of the isocenter position was tested by simulating a complete treatment on the anthropomorphic phantom Alderson Rando, inserting in between two phantom slices a high sensitivity Gafchromic EBT film, properly prepared and calibrated, and repeating several treatment sessions, each time removing the fixing mask and replacing the film inside the phantom. The comparison between the dose distributions measured on films and computed by TPS, after a precise image registration procedure performed by a commercial piece of software (FILMQA, 3cognition LLC (Division of ISP), Wayne, NJ), allowed the authors to measure the repositioning errors, obtaining about 0.5 mm in case of central spherical PTV and about 1.5 mm in case of peripheral irregular PTV. Moreover, an evaluation of the errors in the registration procedure was performed, giving negligible values with respect to the quantities to be measured. The above intrinsic two-dimensional estimate of treatment accuracy has to be increased for the error in the third dimension, but the 2 mm margin the authors generally use for the CTV-PTV expansion seems adequate anyway. Using the same EBT films, a dosimetric verification of the treatment planning system was done. Measured dose values are larger or smaller than the nominal ones depending on geometric irradiation conditions, but, in the authors' experimental conditions, always

  15. Contura Multi-Lumen Balloon Breast Brachytherapy Catheter: Comparative Dosimetric Findings of a Phase 4 Trial

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Douglas W., E-mail: darthur@mcvh-vcu.edu [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Vicini, Frank A. [Michigan Healthcare Professionals/21st Century Oncology, Farmington Hills, Michigan (United States); Todor, Dorin A. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Julian, Thomas B. [Allegheny General Hospital, Temple University School of Medicine, Pittsburgh, Pennsylvania (United States); Cuttino, Laurie W.; Mukhopadhyay, Nitai D. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States)

    2013-06-01

    Purpose: Final dosimetric findings of a completed, multi-institutional phase 4 registry trial using the Contura Multi-Lumen Balloon (MLB) breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI) in patients with early-stage breast cancer are presented. Methods and Materials: Three dosimetric plans with identical target coverage were generated for each patient for comparison: multilumen multidwell (MLMD); central-lumen multidwell (CLMD); and central-lumen single-dwell (CLSD) loading of the Contura catheter. For this study, a successful treatment plan achieved ideal dosimetric goals and included the following: ≥95% of the prescribed dose (PD) covering ≥95% of the target volume (TV); maximum skin dose ≤125% of the PD; maximum rib dose ≤145% of the PD; and V150 ≤50 cc and V200 ≤10 cc. Results: Between January 2008 and February 2011, 23 institutions participated. A total of 318 patients were available for dosimetric review. Using the Contura MLB, all dosimetric criteria were met in 78.93% of cases planned with MLMD versus 55.38% with the CLMD versus 37.66% with the CLSD (P≤.0001). Evaluating all patients with the full range of skin to balloon distance represented, median maximum skin dose was reduced by 12% and median maximum rib dose by 13.9% when using MLMD-based dosimetric plans compared to CLSD. The dosimetric benefit of MLMD was further demonstrated in the subgroup of patients where skin thickness was <5 mm, where MLMD use allowed a 38% reduction in median maximum skin dose over CLSD. For patients with rib distance <5 mm, the median maximum rib dose reduction was 27%. Conclusions: Use of the Contura MLB catheter produced statistically significant improvements in dosimetric capabilities between CLSD and CLMD treatments. This device approach demonstrates the ability not only to overcome the barriers of limited skin thickness and close rib proximity, but to consistently achieve a higher standard of dosimetric planning goals.

  16. Contura Multi-Lumen Balloon breast brachytherapy catheter: comparative dosimetric findings of a phase 4 trial.

    Science.gov (United States)

    Arthur, Douglas W; Vicini, Frank A; Todor, Dorin A; Julian, Thomas B; Cuttino, Laurie W; Mukhopadhyay, Nitai D

    2013-06-01

    Final dosimetric findings of a completed, multi-institutional phase 4 registry trial using the Contura Multi-Lumen Balloon (MLB) breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI) in patients with early-stage breast cancer are presented. Three dosimetric plans with identical target coverage were generated for each patient for comparison: multilumen multidwell (MLMD); central-lumen multidwell (CLMD); and central-lumen single-dwell (CLSD) loading of the Contura catheter. For this study, a successful treatment plan achieved ideal dosimetric goals and included the following: ≥ 95% of the prescribed dose (PD) covering ≥ 95% of the target volume (TV); maximum skin dose ≤ 125% of the PD; maximum rib dose ≤ 145% of the PD; and V150 ≤50 cc and V200 ≤ 10 cc. Between January 2008 and February 2011, 23 institutions participated. A total of 318 patients were available for dosimetric review. Using the Contura MLB, all dosimetric criteria were met in 78.93% of cases planned with MLMD versus 55.38% with the CLMD versus 37.66% with the CLSD (P ≤.0001). Evaluating all patients with the full range of skin to balloon distance represented, median maximum skin dose was reduced by 12% and median maximum rib dose by 13.9% when using MLMD-based dosimetric plans compared to CLSD. The dosimetric benefit of MLMD was further demonstrated in the subgroup of patients where skin thickness was <5 mm, where MLMD use allowed a 38% reduction in median maximum skin dose over CLSD. For patients with rib distance <5 mm, the median maximum rib dose reduction was 27%. Use of the Contura MLB catheter produced statistically significant improvements in dosimetric capabilities between CLSD and CLMD treatments. This device approach demonstrates the ability not only to overcome the barriers of limited skin thickness and close rib proximity, but to consistently achieve a higher standard of dosimetric planning goals. Copyright © 2013 Elsevier Inc. All rights

  17. 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

  18. Modelling the effect of non-uniform radon progeny activities on transformation frequencies in human bronchial airways

    International Nuclear Information System (INIS)

    Fakir, H.; Hofmann, W.; Aubineau-Laniece, I.

    2006-01-01

    The effects of radiological and morphological source heterogeneities in straight and Y-shaped bronchial airways on hit frequencies and Micro-dosimetric quantities in epithelial cells have been investigated previously. The goal of the present study is to relate these physical quantities to transformation frequencies in sensitive target cells and to radon-induced lung cancer risk. Based on an effect-specific track length model, computed linear energy transfer (LET) spectra were converted to corresponding transformation frequencies for different activity distributions and source - target configurations. Average transformation probabilities were considerably enhanced for radon progeny accumulations and target cells at the carinal ridge, relative to uniform activity distributions and target cells located along the curved and straight airway portions at the same exposure level. Although uncorrelated transformation probabilities produce a linear dose - effect relationship, correlated transformations first increase depending on the LET, but then decrease significantly when exceeding a defined number of hits or cumulative exposure level. (authors)

  19. 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

  20. 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

  1. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-15

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

  3. Property of Fluctuations of Sales Quantities by Product Category in Convenience Stores.

    Directory of Open Access Journals (Sweden)

    Gaku Fukunaga

    Full Text Available The ability to ascertain the extent of product sale fluctuations for each store and locality is indispensable to inventory management. This study analyzed POS data from 158 convenience stores in Kawasaki City, Kanagawa Prefecture, Japan and found a power scaling law between the mean and standard deviation of product sales quantities for several product categories. For the statistical domains of low sales quantities, the power index was 1/2; for large sales quantities, the power index was 1, so called Taylor's law holds. The value of sales quantities with changing power indixes differed according to product category. We derived a Poissonian compound distribution model taking into account fluctuations in customer numbers to show that the scaling law could be explained theoretically for most of items. We also examined why the scaling law did not hold in some exceptional cases.

  4. Property of Fluctuations of Sales Quantities by Product Category in Convenience Stores.

    Science.gov (United States)

    Fukunaga, Gaku; Takayasu, Hideki; Takayasu, Misako

    2016-01-01

    The ability to ascertain the extent of product sale fluctuations for each store and locality is indispensable to inventory management. This study analyzed POS data from 158 convenience stores in Kawasaki City, Kanagawa Prefecture, Japan and found a power scaling law between the mean and standard deviation of product sales quantities for several product categories. For the statistical domains of low sales quantities, the power index was 1/2; for large sales quantities, the power index was 1, so called Taylor's law holds. The value of sales quantities with changing power indixes differed according to product category. We derived a Poissonian compound distribution model taking into account fluctuations in customer numbers to show that the scaling law could be explained theoretically for most of items. We also examined why the scaling law did not hold in some exceptional cases.

  5. Examining the relationship between pre- and postimplant geometry in prostate low-dose-rate brachytherapy and its correlation with dosimetric quality using the similarity concept.

    Science.gov (United States)

    Todor, Dorin A; Anscher, Mitchell S; Karlin, Jeremy D; Hagan, Michael P

    2014-01-01

    This is a retrospective study in which we define multiple metrics for similarity and then inquire on the relationship between similarity and currently used dosimetric quantities describing preimplant and postimplant plans. We analyzed a unique cohort of 94 consecutively performed prostate seed implant patients, associated with excellent dosimetric and clinical outcomes. For each patient, an ultrasound (US) preimplant and two CT postimplant (Day 0 and Day 30) studies were available. Measures for similarity were created and computed using feature vectors based on two classes of moments: first, invariant to rotation and translation, and the second polar-radius moments invariant to rotation, translation, and scaling. Both similarity measures were calibrated using controlled perturbations (random and systematic) of seed positions and contours in different size implants, thus producing meaningful numerical threshold values used in the clinical analysis. An important finding is that similarity, for both seed distributions and contours, improves significantly when scaling invariance is added to translation and rotation. No correlation between seed and contours similarity was found. In the setting of preplanned prostate seed implants using preloaded needles, based on our data, similarity between preimplant and postimplant plans does not correlate with either minimum dose to 90% of the volume of the prostate or analogous similarity metrics for prostate contours. We have developed novel tools and metrics, which will allow practitioners to better understand the relationship between preimplant and postimplant plans. Geometrical similarity between a preplan and an actual implant, although useful, does not seem to be necessary to achieve minimum dose to 90% of the volume of the prostate-good dosimetric implants. Copyright © 2014 American Brachytherapy Society. All rights reserved.

  6. Dosimetric characterization and identification of TL defect centres in sand for its application in sludge irradiators as an in situ dosimeter

    International Nuclear Information System (INIS)

    Benny, P.G.; Shah, M.R.; Sabharwal, S.; Bhatt, B.C.; Gundu Rao, T.K.

    2003-08-01

    The report presents investigations that have been carried out to establish a method for the routine/ periodic dosimetry for Sludge Hygienisation Research Irradiator (SHRI) facility set up at Baroda (India) for disinfection of liquid sewage sludge in bulk quantity. For this purpose, the possibility of using the sand, one of the components of inorganic matter found in sewage sludge, directly as a TL dosimeter has been explored. The report is presented in two parts. Part 1 presents dosimetric characterization of sand for its application as an in situ dosimeter. A review on various sewage sludge irradiators operating in the world and the different dosimetric techniques used for these facilities are briefly described. In the present studies, in order to investigate the thermoluminescence properties of sand, it was separated from the sewage sludge by an extensive cleaning procedure. Part 1 also describes the procedure for separation of sand from sewage sludge, study on its TL properties, dosimetric characterization of sand and application of cleaned sand collected at the outlet of the SHRI facility for estimating radiation absorbed dose imparted to the sludge during its disinfection as well as for determining distribution of dose for an irradiated sludge batch. A new method by using phototransferred thermoluminescence (PTTL) in quartz separated from sand has been explored for high-level gamma dosimetry. Part 2 of the report presents sensitization properties of TL peaks and study of TL defect centres in quartz. It describes the results on pre-dose sensitization of 220 degC and 110 degC TL peaks in the quartz samples separated from sand. From the TL and ESR studies, a mechanism for TL sensitization has been suggested, which involves the role of competing traps and E I - centres in the sensitization process. The paramagnetic radicals formed in quartz samples after gamma irradiation by using ESR technique have been briefly described. (author)

  7. 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)

  8. 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

  9. 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)

  10. 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

  11. 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

  12. 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)

  13. Dosimetric characterization of KMgF3:Tb+PTFE

    International Nuclear Information System (INIS)

    Ramirez R, M. I.; Garcia S, L.; Villicana M, M.; Huirache A, R.; Apolinar C, J.; Gonzalez M, P. R.

    2017-10-01

    In this work the results obtained from the dosimetric characterization of the new radiation detectors of KMgF 3 :Tb+PTFE are presented. The host salt was obtained by means of the microwave technique, with the polycrystalline powder obtained, dosimeters were made in tablet form, using as Ptfe binder. The thermoluminescent response of these new detectors presented a linear behavior, in the dose range between 1 and 1000 Gy of 60 Co gamma radiation, the reproducibility test in the measurements, during ten cycles of heat treatment, irradiation and reading presented ± 3.7% Ds, in the stability test of thermoluminescent signal, during two months showed that the fading is practically null. Due to the results obtained, this new detector could be very useful for the dosimetry of ionizing radiation in different clinical applications. (Author)

  14. 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)

  15. Dosimetric characteristics of LKB:Cu,P solid TL detector

    International Nuclear Information System (INIS)

    Hashim, S.; Alajerami, Y.S.M.; Ghoshal, S.K.; Saleh, M.A.; Saripan, M.I.; Kadir, A.B.A.; Bradley, D.A.; Alzimami, K.

    2014-01-01

    The dosimetric characteristics of newly developed borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and NH 4 H 2 PO 4 are reported. Broad peaks in the absence of any sharp peak confirms the amorphous nature of the prepared glass. A simple glow curve of Cu doped sample is observed with a single prominent peak (T m ) at 220 °C. The TL intensity response shows an enhancement of ∼100 times due to the addition of CuO (0.1 mol%) to LKB compound. A further enhancement of the intensity by a factor of 3 from the addition of 0.25 mol% NH 4 H 2 PO 4 as a co-dopant impurity is attributed to the creation of extra electron traps with consequent increase in energy transfer of radiation recombination centers. The TL yield performance of LKB:Cu,P with Z eff ≈8.92 is approximately seventeen times less sensitive compared to LiF:Mg,Ti (TLD-100). The proposed dosimeter shows good linearity up to 10 3 Gy, minimal fading and photon energy independence. These attractive features offered by our dosimeter is expected to pave the way towards dosimetric applications. - Highlights: • The NH 4 H 2 PO 4 impurities are cross linked with the CuO defect. • The addition of NH 4 H 2 PO 4 as a co-dopant improved the TL intensity by a factor of 3. • The proposed dosimeter shows good linearity up to 10 3 Gy. • Minimal fading and photon energy independence were observed

  16. 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

  17. Dosimetric Analysis of Respiratory-Gated Radiotherapy for Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Xi Mian; Zhang Li; Liu Mengzhong; Deng Xiaowu; Huang Xiaoyan; Liu Hui

    2011-01-01

    The purpose of this study was to define individualized internal target volume (ITV) for hepatocellular carcinoma (HCC) using 4D computed tomography (4DCT), and to determine the geometric and dosimetric benefits of respiratory gating. Gross tumor volumes (GTVs) were contoured on 10 respiratory phases of 4DCT images for 12 patients with HCC. Three treatment plans were prepared using different planning target volumes (PTVs): (1) PTV 3D , derived from a single helical clinical target volume (CTV) plus conventional margins; (2) PTV 10phases , derived from ITV 10phases , which encompassed all 10 CTVs plus an isotropic margin of 0.8 cm; (3) PTV gating , derived from ITV gating , which encompassed three CTVs within gating-window at end-expiration plus an isotropic margin of 0.8 cm. The PTV 3D was the largest volume for all patients. The ITV-based plans and gating plans spared more normal tissues than 3D plans, especially the liver. Without increasing normal tissue complication probability of the 3D plans, the ITV-based plans allowed for increasing the calculated dose from 50.8 Gy to 54.7 Gy on average, and the gating plans could further escalate the dose to 58.5 Gy. Compared with ITV-based plans, the dosimetric gains with gating plan strongly correlated with GTV mobility in the craniocaudal direction. The ITV-based plans can ensure target coverage with less irradiation of normal tissues compared with 3D plans. Respiratory-gated radiotherapy can further reduce the target volumes to spare more surrounding tissues and allow dose escalation, especially for patients with tumor mobility >1 cm.

  18. On the half-life of luminescence signals in dosimetric applications: A unified presentation

    Science.gov (United States)

    Pagonis, V.; Kitis, G.; Polymeris, G. S.

    2018-06-01

    Luminescence signals from natural and man-made materials are widely used in dosimetric and dating applications. In general, there are two types of half-lives of luminescence signals which are of importance to experimental and modeling work in this research area. The first type of half-life is the time required for the population of the trapped charge in a single trap to decay to half its initial value. The second type of half-life is the time required for the luminescence intensity to drop to half of its initial value. While there a handful of analytical expressions available in the literature for the first type of half-life, there are no corresponding analytical expressions for the second type. In this work new analytical expressions are derived for the half-life of luminescence signals during continuous wave optical stimulation luminescence (CW-OSL) or isothermal luminescence (ITL) experiments. The analytical expressions are derived for several commonly used luminescence models which are based on delocalized transitions involving the conduction band: first and second order kinetics, empirical general order kinetics (GOK), mixed order kinetics (MOK) and the one-trap one-recombination center (OTOR) model. In addition, half-life expressions are derived for a different type of luminescence model, which is based on localized transitions in a random distribution of charges. The new half-life expressions contain two parts. The first part is inversely proportional to the thermal or optical excitation rate, and depends on the experimental conditions and on the cross section of the relevant luminescence process. The second part is characteristic of the optical and/or thermal properties of the material, as expressed by the parameters in the model. A new simple and quick method for analyzing luminescence signals is developed, and examples are given of applying the new method to a variety of dosimetric materials. The new test allows quick determination of whether a set of

  19. Is the Quantity Theory of Money Useful in Forecasting U.S. Inflation?

    DEFF Research Database (Denmark)

    Lanne, Markku; Luoto, Jani; Nyberg, Henri

    We propose a new simple model incorporating the implication of the quantity theory of money that money growth and ináation should move one for one in the long run, and, hence, ináation should be predictable by money growth. The model Öts postwar U.S. data well, and beats common univariate benchma...... models in forecasting ináation. Moreover, this evidence is quite robust, and predictability is found also in the Great moderation period. The detected predictability of ináation by money growth lends support to the quantity theory....

  20. Dosimetric properties of a novel brachytherapy balloon applicator for the treatment of malignant brain-tumor resection-cavity margins

    International Nuclear Information System (INIS)

    Dempsey, James F.; Williams, Jeffery A.; Stubbs, James B.; Patrick, Timothy J.; Williamson, Jeffrey F.

    1998-01-01

    Purpose: This paper characterizes the dosimetric properties of a novel balloon brachytherapy applicator for the treatment of the tissue surrounding the resection cavity of a malignant brain tumor. Methods and Materials: The applicator consists of an inflatable silicone balloon reservoir attached to a positionable catheter that is intraoperatively implanted into the resection cavity and postoperatively filled with a liquid radionuclide solution. A simple dosimetric model, valid in homogeneous media and based on results from Monte Carlo photon-transport simulations, was used to determine the dosimetric characteristics of spherical geometry balloons filled with photon-emitting radionuclide solutions. Fractional depth-dose (FDD) profiles, along with activity densities, and total activities needed to achieve specified dose rates were studied as a function of photon energy and source-containment geometry. Dose-volume histograms (DVHs) were calculated to compare idealized balloon-applicator treatments to conventional 125 I seed volume implants. Results: For achievable activity densities and total activities, classical low dose rate (LDR) treatments of residual disease at distances of up to 1 cm from the resection cavity wall are possible with balloon applicators having radii between 0.5 cm and 2.5 cm. The dose penetration of these applicators increases approximately linearly with balloon radius. The FDD profile can be made significantly more or less penetrating by combining selection of radionuclide with source-geometry manipulation. Comparisons with 125 I seed-implant DVHs show that the applicator can provide a more conformal therapy with no target tissue underdosing, less target tissue overdosing, and no healthy tissue ''hot spots;'' however, more healthy tissue volume receives a dose of the prescribed dosage or less. Conclusions: This device, when filled with 125 I solution, is suitable for classical LDR treatments and may be preferable to 125 I interstitial

  1. 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

  2. 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

  3. Algebraic quantity equations before Fisher and Pigou

    OpenAIRE

    Thomas M. Humphrey

    1984-01-01

    Readers of this Review are doubtlessly familiar with the famous equation of exchange, MV=PQ, frequently employed to analyze the price level effects of monetary shocks. One might think the algebraic formulation of the equation is an outgrowth of the 20th century tendency toward mathematical modeling and statistical testing. Indeed, textbooks typically associate the transaction velocity version of the equation with Irving Fisher and the alternative Cambridge cash balance version with A. C. Pigo...

  4. Practical realisation of individual dosimetric control of internal and external irradiation during works at 'Ukrytie' shelter

    International Nuclear Information System (INIS)

    Likhtarev, I.A.; Bondarenko, O.S.; Berkovskij, V.B.; Chumak, V.K.; Korneev, A.A.; Dmitrienko, A.V.

    1999-01-01

    Individual dosimetric control requires the minimisation of personnel irradiation doses and needs forecasting and planning of dose loads. System of individual dose control and its functions at 'Ukrytie' shelter are described

  5. SU-E-T-342: Use of Patient Geometry Measurements to Predict Dosimetric Gain with VMAT Over 3D for Chestwall and Regional Nodal Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Dumane, V; Knoll, M; Green, S; Bakst, R [The Mount Sinai Medical Center, NY, NY (United States); Hunt, M [Mem Sloan-Kettering Cancer Ctr, NY, NY (United States); Steinberger, E [The Mount Sinai School of Medicine, NY, NY (United States)

    2014-06-01

    Purpose: To predict the dosimetric gain of VMAT over 3D for the treatment ofchestwall/IMN/supraclavicular nodes using geometric parameters acquired during simulation Methods: CT scans for 20 left and 20 right sided patients were retrospectively analyzed toobtain percent ipsilateral lung volume included in the PWT and supraclavicular fields, central lung depth (CLD), maximum lung depth (MLD), separation, chestwall concavity (defined here as the product of CLD and separation) and the maximum heart depth (MHD). VMAT, PWT and P/E plans were done for each case. The ipsilateral lung V20 Gy and mean, total lung V20 Gy and mean, heart V25 Gy and mean were noted for each plan. Correlation coefficients were obtained and linear regression models were built using data from the above training set of patients and then tested on 4 new patients. Results: The decrease in ipsilateral lung V20 Gy, total lung V20 Gy, ipsilateral lung mean and total lung mean with VMAT over PWT significantly (p<0.05) correlated with the percent volume of ipsilateral lung included in the PWT and supraclavicular fields with correlation coefficient values of r = 0.83, r = 0.77, r = 0.78 and r = 0.75 respectively. Significant correlations were also found between MHD and the decrease in heart V25 Gy and mean of r = 0.77 and r = 0.67 respectively. Dosimetric improvement with VMAT over P/E plans showed no correlation to any of the geometric parameters investigated in this study. The dosimetric gain predicted for the 4 test cases by the linear regression models given their respective percent ipsilateral lung volumes fell within the 95% confidence intervals around the best regression fit. Conclusion: The percent ipsilateral lung volume appears to be a strong predictor of the dosimetric gain on using VMAT over PWT apriori.

  6. SU-E-T-342: Use of Patient Geometry Measurements to Predict Dosimetric Gain with VMAT Over 3D for Chestwall and Regional Nodal Radiation

    International Nuclear Information System (INIS)

    Dumane, V; Knoll, M; Green, S; Bakst, R; Hunt, M; Steinberger, E

    2014-01-01

    Purpose: To predict the dosimetric gain of VMAT over 3D for the treatment ofchestwall/IMN/supraclavicular nodes using geometric parameters acquired during simulation Methods: CT scans for 20 left and 20 right sided patients were retrospectively analyzed toobtain percent ipsilateral lung volume included in the PWT and supraclavicular fields, central lung depth (CLD), maximum lung depth (MLD), separation, chestwall concavity (defined here as the product of CLD and separation) and the maximum heart depth (MHD). VMAT, PWT and P/E plans were done for each case. The ipsilateral lung V20 Gy and mean, total lung V20 Gy and mean, heart V25 Gy and mean were noted for each plan. Correlation coefficients were obtained and linear regression models were built using data from the above training set of patients and then tested on 4 new patients. Results: The decrease in ipsilateral lung V20 Gy, total lung V20 Gy, ipsilateral lung mean and total lung mean with VMAT over PWT significantly (p<0.05) correlated with the percent volume of ipsilateral lung included in the PWT and supraclavicular fields with correlation coefficient values of r = 0.83, r = 0.77, r = 0.78 and r = 0.75 respectively. Significant correlations were also found between MHD and the decrease in heart V25 Gy and mean of r = 0.77 and r = 0.67 respectively. Dosimetric improvement with VMAT over P/E plans showed no correlation to any of the geometric parameters investigated in this study. The dosimetric gain predicted for the 4 test cases by the linear regression models given their respective percent ipsilateral lung volumes fell within the 95% confidence intervals around the best regression fit. Conclusion: The percent ipsilateral lung volume appears to be a strong predictor of the dosimetric gain on using VMAT over PWT apriori

  7. Modeling the Impacts of Hydromodification on Water Quantity and Quality

    Science.gov (United States)

    Hydromodification activities are driven by human population growth and resource extraction and consumption including urbanization, agriculture, forestry, mining, water withdrawal, climate change, and flow regulation by dams and impoundments. These anthropogenic activities alter n...

  8. 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)

  9. 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

  10. Improvements in critical dosimetric endpoints using the Contura multilumen balloon breast brachytherapy catheter to deliver accelerated partial breast irradiation: preliminary dosimetric findings of a phase iv trial.

    Science.gov (United States)

    Arthur, Douglas W; Vicini, Frank A; Todor, Dorin A; Julian, Thomas B; Lyden, Maureen R

    2011-01-01

    Dosimetric findings in patients treated with the Contura multilumen balloon (MLB) breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI) on a multi-institutional Phase IV registry trial are presented. Computed tomography-based three-dimensional planning with dose optimization was performed. For the trial, new ideal dosimetric goals included (1) ≥95% of the prescribed dose (PD) covering ≥90% of the target volume, (2) a maximum skin dose ≤125% of the PD, (3) maximum rib dose ≤145% of the PD, and (4) the V150 ≤50 cc and V200 ≤10 cc. The ability to concurrently achieve these dosimetric goals using the Contura MLB was analyzed. 144 cases were available for review. Using the MLB, all dosimetric criteria were met in 76% of cases. Evaluating dosimetric criteria individually, 92% and 89% of cases met skin and rib dose criteria, respectively. In 93% of cases, ideal target volume coverage goals were met, and in 99%, dose homogeneity criteria (V150 and V200) were satisfied. When skin thickness was ≥5 mm to <7 mm, the median skin dose was limited to 120.1% of the PD, and when skin thickness was <5 mm, the median skin dose was 124.2%. When rib distance was <5 mm, median rib dose was reduced to 136.5% of the PD. When skin thickness was <7 mm and distance to rib was <5 mm, median skin and rib doses were jointly limited to 120.6% and 142.1% of the PD, respectively. The Contura MLB catheter provided the means of achieving the imposed higher standard of dosimetric goals in the majority of clinical scenarios encountered. Copyright © 2011 Elsevier Inc. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yang, James N.; Pino, Ramiro [Department of Radiation Physics, Unit 94, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiology, Baylor College of Medicine and Methodist Hospital, Houston, Texas 77030 (United States)

    2008-10-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-03-07

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

  13. 48 CFR 52.217-6 - Option for Increased Quantity.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Option for Increased....217-6 Option for Increased Quantity. As prescribed in 17.208(d), insert a clause substantially the same as the following: Option for Increased Quantity (MAR 1989) The Government may increase the...

  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. 30 CFR 75.322 - Harmful quantities of noxious gases.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Harmful quantities of noxious gases. 75.322... quantities of noxious gases. Concentrations of noxious or poisonous gases, other than carbon dioxide, shall... Governmental Industrial Hygienists in “Threshold Limit Values for Substance in Workroom Air” (1972). Detectors...

  17. 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.

  18. 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)

  19. 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 ...

  20. 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...

  1. 21 CFR 1314.20 - Restrictions on sales quantity.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Restrictions on sales quantity. 1314.20 Section 1314.20 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE RETAIL SALE OF SCHEDULED LISTED CHEMICAL PRODUCTS Sales by Regulated Sellers § 1314.20 Restrictions on sales quantity. (a) Without...

  2. Quantifying cannabis: A field study of marijuana quantity estimation.

    Science.gov (United States)

    Prince, Mark A; Conner, Bradley T; Pearson, Matthew R

    2018-05-17

    The assessment of marijuana use quantity poses unique challenges. These challenges have limited research efforts on quantity assessments. However, quantity estimates are critical to detecting associations between marijuana use and outcomes. We examined accuracy of marijuana users' estimations of quantities of marijuana they prepared to ingest and predictors of both how much was prepared for a single dose and the degree of (in)accuracy of participants' estimates. We recruited a sample of 128 regular-to-heavy marijuana users for a field study wherein they prepared and estimated quantities of marijuana flower in a joint or a bowl as well as marijuana concentrate using a dab tool. The vast majority of participants overestimated the quantity of marijuana that they used in their preparations. We failed to find robust predictors of estimation accuracy. Self-reported quantity estimates are inaccurate, which has implications for studying the link between quantity and marijuana use outcomes. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  3. 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

  4. 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.

  5. 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

  6. Dynamic Coding of Signed Quantities in Cortical Feedback Circuits

    Directory of Open Access Journals (Sweden)

    Dana eBallard

    2012-08-01

    Full Text Available In the early sensory and motor areas of the cortex, individual neurons transmit information about specific sensory features via a peaked response. This concept has been crystallized as `labeled lines,' to denote that axons communicate the specific properties of their sensory or motor parent cell. Such cells also can be characterized as being polarized, that is, as representing a signed quantity that is either positive or negative. We show in a model simulation that there are two important consequences when learning receptive fields using such signed codings in circuits that subtract different inputs. The first is that, in feedback circuits using labeled lines, such arithmetic operations need to be distributed across multiple distinct pathways. The second consequence is that such pathways must be necessarily dynamic, i.e. that synapses can grow and retract when forming receptive fields. The model monitors the breaking and growing of new circuit connections when their synapses need to change polarities and predicts that the rate of such changes should be inversely correlated with the progress of receptive field formation.

  7. Radiochromic film in the dosimetric verification of intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Zhou Yingjuan; Huang Shaomin; Deng Xiaowu

    2007-01-01

    Objective: Objective To investigate the dose-response behavior of a new type of radio- chromic film( GAFCHROMIC EBT) and explore the clinical application means and precision of dosage measurement, which can be applied for: (1) plan-specific dosimetric verification for intensity modulated radiation therapy, (2) to simplify the process of quality assurance using traditional radiographic film dosimetric system and (3) to establish a more reliable, more efficient dosimetric verification system for intensity modulated radiation therapy. Methods: (1) The step wedge calibration technique was used to calibrate EBT radiochromic film and EDR2 radiographic film. The dose characteristics, the measurement consistency and the quality assurance process between the two methods were compared. (2) The in-phantom dose-measurement based verification technique has been adopted. Respectively, EBT film and EDR2 film were used to measure the same dose plane of IMRT treatment plans. The results of the dose map, dose profiles and iso- dose curves were compared with those calculated by CORVUS treatment planning system to evaluate the function of EBT film for dosimetric verification for intensity modulated radiation therapy. Results: (1) Over the external beam dosimetric range of 0-500 cGy, EBT/VXR-16 and EDR2/VXR-16 film dosimetric system had the same measurement consistency with the measurement variability less then 0.70%. The mean measurement variability of these two systems was 0.37% and 0.68%, respectively. The former proved to be the superior modality at measurement consistency, reliability, and efficiency over dynamic clinical dose range , furthermore, its quality assurance showed less process than the latter. (2) The dosimetric verification of IMRT plane measured with EBT film was quite similar to that with EDR2 film which was processed under strict quality control. In a plane of the phantom, the maximal dose deviation off axis between EBT film measurement and the TPS calculation was

  8. Prediction of Radiation Esophagitis in Non–Small Cell Lung Cancer Using Clinical Factors, Dosimetric Parameters, and Pretreatment Cytokine Levels

    Directory of Open Access Journals (Sweden)

    Peter G. Hawkins

    2018-02-01

    Full Text Available Radiation esophagitis (RE is a common adverse event associated with radiotherapy for non–small cell lung cancer (NSCLC. While plasma cytokine levels have been correlated with other forms of radiation-induced toxicity, their association with RE has been less well studied. We analyzed data from 126 patients treated on 4 prospective clinical trials. Logistic regression models based on combinations of dosimetric factors [maximum dose to 2 cubic cm (D2cc and generalized equivalent uniform dose (gEUD], clinical variables, and pretreatment plasma levels of 30 cytokines were developed. Cross-validated estimates of area under the receiver operating characteristic curve (AUC and log likelihood were used to assess prediction accuracy. Dose-only models predicted grade 3 RE with AUC values of 0.750 (D2cc and 0.727 (gEUD. Combining clinical factors with D2cc increased the AUC to 0.779. Incorporating pretreatment cytokine measurements, modeled as direct associations with RE and as potential interactions with the dose-esophagitis association, produced AUC values of 0.758 and 0.773, respectively. D2cc and gEUD correlated with grade 3 RE with odds ratios (ORs of 1.094/Gy and 1.096/Gy, respectively. Female gender was associated with a higher risk of RE, with ORs of 1.09 and 1.112 in the D2cc and gEUD models, respectively. Older age was associated with decreased risk of RE, with ORs of 0.992/year and 0.991/year in the D2cc and gEUD models, respectively. Combining clinical with dosimetric factors but not pretreatment cytokine levels yielded improved prediction of grade 3 RE compared to prediction by dose alone. Such multifactorial modeling may prove useful in directing radiation treatment planning.

  9. 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)

  10. 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.)

  11. Supply Chain Coordination under Trade Credit and Quantity Discount with Sales Effort Effects

    Directory of Open Access Journals (Sweden)

    Zhihong Wang

    2018-01-01

    Full Text Available The purpose of this paper is to investigate the role of trade credit and quantity discount in supply chain coordination when the sales effort effect on market demand is considered. In this paper, we consider a two-echelon supply chain consisting of a single retailer ordering a single product from a single manufacturer. Market demand is stochastic and is influenced by retailer sales effort. We formulate an analytical model based on a single trade credit and find that the single trade credit cannot achieve the perfect coordination of the supply chain. Then, we develop a hybrid quantitative analytical model for supply chain coordination by coherently integrating incentives of trade credit and quantity discount with sales effort effects. The results demonstrate that, providing that the discount rate satisfies certain conditions, the proposed hybrid model combining trade credit and quantity discount will be able to effectively coordinate the supply chain by motivating retailers to exert their sales effort and increase product order quantity. Furthermore, the hybrid quantitative analytical model can provide great flexibility in coordinating the supply chain to achieve an optimal situation through the adjustment of relevant parameters to resolve conflict of interests from different supply chain members. Numerical examples are provided to demonstrate the effectiveness of the hybrid model.

  12. 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)

  13. 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.)

  14. N-13 labeled amino acids: biodistribution, metabolism and dosimetric considerations

    International Nuclear Information System (INIS)

    Rosenspire, K.C.; Gelbard, A.S.

    1986-01-01

    With the growing interest in metabolic imaging and with the increasing number of cyclotron/PET facilities, more studies are being performed in animal and humans using short-lived positron-emitting radionuclides. Amino acids labeled either with N-13 or C-11 are one group of compounds being used to study in vivo regional organ (i.e., brain and heart) or tumor metabolism. Of the studies previously reported using C-11 or N-13 labeled amino acids (methionine, alanine, valine, glutamate, glutamine and tryptophan), imaging was restricted mainly to the organ or tissue of interest with little information obtained about the whole-bode distribution of the label. Such data are important for studying interorgan transport of amino acids and for determining accurate dosimetric measurements after intravenous injection of labeled amino acids. The goals of the authors study were to compare the distribution of several N-13 L-amino acids and N-13 ammonia in tumor-bearing mice and to determine the metabolic fate of the label in vivo. The following amino acids were enzymatically labeled using N-13 ammonia: glutamine, glutamate, methionine, α-aminobutyric acid, valine and leucine. 30 references, 2 figures, 14 tables

  15. WE-DE-209-01: Dosimetric Benefits of DIBH

    Energy Technology Data Exchange (ETDEWEB)

    Howell, R. [UT MD Anderson Cancer Center (United States)

    2016-06-15

    Breast radiation therapy is associated with some risk of lung toxicity as well as cardiac toxicity for left-sided cases. Radiation doses to the lung and heart can be reduced by using the deep inspiration breath hold (DIBH) technique, in which the patient is simulated and treated during the deep inspiration phase of the breathing cycle. During DIBH, the heart is usually displaced posteriorly, inferiorly, and to the right, effectively expanding the distance between the heart and the breast/chest wall. As a result, the distance between the medial treatment field border and heart/lung is increased. Also, in a majority of DIBH patients, the air drawn into the thoracic cavity increases the total lung volume. The DIBH was discussed by an AAPM Task Group 10 years ago in the AAPM TG 76 report. However, DIBH is still not the standard of care in many clinics, which may be partially due to challenges associated with its implementation. Therefore, this seccion will focus primarily on how to clinically implement four different DIBH techniques: (1) Active Breathing Control, (2) Spirometric Motion Management, (3) 3D Surface Image-Guided, and (4) Self-held Breath Control with Respiratory Monitoring and Feedback Guidance. Learning Objectives: Describe the physical displacement of the heart and the change in lung volume during DIBH and discuss dosimetric consequences of those changes. Provide an overview of the technical aspects. Describe work flow for patient simulation and treatment. Give an overview of commissioning and routine. Provide practical tips for clinical implementation.

  16. Dosimetric considerations in radioimmunotherapy of patients with hepatoma

    International Nuclear Information System (INIS)

    Leichner, P.K.; Klein, J.L.; Order, S.E.

    1986-01-01

    Dosimetric studies of I-131 labeled antiferritin have provided the foundation for preparative and administrative aspects of radiolabeled antibody treatment of patients with hepatoma. Tumor response to I-131 labeled antiferritin IgG was encouraging and radioimmunotherapy with Y-90 labeled antiferritin IgG was recently initiated. For these patients, In-111 labeled antiferritin IgG was used as the imaging agent, with administered activities ranging from 0.8 - 7 mCi. Serial gamma camera imaging from 30 minutes to 6 days post injection demonstrated that 5-30% of the administered activity localized in hepatomas (8/12 patients). The mean value of the effective half-life in the tumor and liver was 2.8 d. Disappearance curves for the blood circulation, spleen, and other normal tissues were biphasic such that 50% of the activity disappeared within 24 hours post injection. The eight patients who demonstrated sufficient tumor localization where subsequently treated with Y-90 labeled antiferritin IgG. Administered activities were dependent on tumor volume and uptake of radiolabeled IgG and ranged from 8 - 20 mCi. The remaining patients were treated under other existing protocols. 10 references

  17. Study on dosimetric properties of radiophotoluminescent glass rod detector

    Energy Technology Data Exchange (ETDEWEB)

    Rah, Jeong Eun; Hong, Ju Young; Suh, Tea Suk [The Catholic University of Korea, Seoul (Korea, Republic of); Shin, Dong Oh [Kyunghee Univ., Seoul (Korea, Republic of); Kim, Hee Sun [Korea Hydro and Nuclear Power Co., Ltd, Daejeon (Korea, Republic of); Lim, Chun Il; Jeong, Hee Gyo [Korea Food and Drug Administration, Seoul (Korea, Republic of)

    2006-12-15

    A radiophotoluminescent Glass Rod Detector (GRD) system has recently become commercially available. We investigate the dosimetric properties of the GRD regarding the reproducibility of signal, dose linearity and energy dependence. The reproducibility of five measurements for 50 GRDs is presented by an average of one standard deviation of each GRD and it is {+-}1.2%. It is found to be linear in response to doses of {sup 60}Co beam in the range 0.5 to 50 Gy with a coefficient of linearity of 0.9998. The energy dependence of the GRD is determined by comparing the dose obtained using cylindrical chamber to that by using the GRD. The GRD response for each beam is normalized to the response for a {sup 60}Co beam. The responses for 6 and 15 MV x-ray beams are within {+-}1.5% (1SD). The energy response of GRD for high-energy photon is almost the same as the energy dependence of LiF:Mg:Ti (TLD-100) and shows little energy dependence unlike p-type silicon diode detector. The GRDs have advantages over other detectors such diode detector, and TLD: linearity, reproducibility and energy dependency. It has been verified to be an effective device for small field dosimetry for stereotactic radiosurgery.

  18. 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)

  19. A reticle retrofit and dosimetric consideration for a linear accelerator.

    Science.gov (United States)

    Krithivas, V

    1996-01-01

    An imperfect reticle system in an accelerator causes uncertainties in source-skin distance (SSD), off-axis distance (OAD), isocenter, and so forth. A reticle was designed and fabricated, and its implications on x-ray and electron beam dosimetry were investigated. A new reticle frame was dimensioned to fit snugly in the accelerator. The frame was fabricated to carry a pair of adjustable cross wires and to allow the machine operation in the photon and electron modes. The impact of the cross wires on 6 MV photon and 5-10 MeV electron beam parameters such as dose rate (Gy/monitor unit), beam uniformity, surface dose, and so forth, were studied using suitable ion chambers and phantoms. The retrofitted system offered long-term mechanical stability leading to precise SSD, OAD, and isocenter measurements. Changes introduced by the cross wires on the 6 MV photon and 5-10 MeV electron beams are presented. Long-term stability of a reticle in an accelerator is important for an accurate patient setup and for making reliable dosimetric measurements. Beam characteristrics have to be studied whenever modifications on a reticle system are made.

  20. 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)

  1. Dosimetric characteristics of a MOSFET dosimeter for clinical electron beams.

    Science.gov (United States)

    Manigandan, D; Bharanidharan, G; Aruna, P; Devan, K; Elangovan, D; Patil, Vikram; Tamilarasan, R; Vasanthan, S; Ganesan, S

    2009-09-01

    The fundamental dosimetric characteristics of commercially available metal oxide semiconductor field effect transistor (MOSFET) detectors were studied for clinical electron beam irradiations. MOSFET showed excellent linearity against doses measured using an ion chamber in the dose range of 20-630cGy. MOSFET reproducibility is better at high doses compared to low doses. The output factors measured with the MOSFET were within +/-3% when compared with those measured with a parallel plate chamber. From 4 to 12MeV, MOSFETs showed a large angular dependence in the tilt directions and less in the axial directions. MOSFETs do not show any dose-rate dependence between 100 and 600MU/min. However, MOSFETs have shown under-response when the dose per pulse of the beam is decreased. No measurable effect in MOSFET response was observed in the temperature range of 23-40 degrees C. The energy dependence of a MOSFET dosimeter was within +/-3.0% for 6-18MeV electron beams and 5.5% for 4MeV ones. This study shows that MOSFET detectors are suitable for dosimetry of electron beams in the energy range of 4-18MeV.

  2. 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)

  3. 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)

  4. Monte Carlo simulations and dosimetric studies of an irradiation facility

    Energy Technology Data Exchange (ETDEWEB)

    Belchior, A. [Instituto Tecnologico e Nuclear, Estrada nacional no. 10, Apartado 21, 2686-953 Sacavem (Portugal)], E-mail: anabelchior@itn.pt; Botelho, M.L; Vaz, P. [Instituto Tecnologico e Nuclear, Estrada nacional no. 10, Apartado 21, 2686-953 Sacavem (Portugal)

    2007-09-21

    There is an increasing utilization of ionizing radiation for industrial applications. Additionally, the radiation technology offers a variety of advantages in areas, such as sterilization and food preservation. For these applications, dosimetric tests are of crucial importance in order to assess the dose distribution throughout the sample being irradiated. The use of Monte Carlo methods and computational tools in support of the assessment of the dose distributions in irradiation facilities can prove to be economically effective, representing savings in the utilization of dosemeters, among other benefits. One of the purposes of this study is the development of a Monte Carlo simulation, using a state-of-the-art computational tool-MCNPX-in order to determine the dose distribution inside an irradiation facility of Cobalt 60. This irradiation facility is currently in operation at the ITN campus and will feature an automation and robotics component, which will allow its remote utilization by an external user, under REEQ/996/BIO/2005 project. The detailed geometrical description of the irradiation facility has been implemented in MCNPX, which features an accurate and full simulation of the electron-photon processes involved. The validation of the simulation results obtained was performed by chemical dosimetry methods, namely a Fricke solution. The Fricke dosimeter is a standard dosimeter and is widely used in radiation processing for calibration purposes.

  5. 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)

  6. Technical and dosimetric aspects of quality control in mammography

    International Nuclear Information System (INIS)

    Zoetelief, J.; Wit, N.J.P. de; Broerse, J.J.

    1989-01-01

    Before screening programmes using mammography are implemented, a cost benefit analysis has to be made and quality-control programme for the technical and dosimetric aspects adopted, including daily checks on film processing and total mammography procedure (radiography of a reference phantom, for which the average density, limiting value ± 0.20%, and focal charge is determined and which allows assessment of physical image quality) The installation of a MAs meter is essential for daily checks and can be used for determination of absorbed dose. Accurate determination of tube voltage (limiting value ±0.5 kV) is essential in regard to absorbed dose variations. Focal spot size should be measured rather than relying on the value specified by the manufacturer. The determination of the focal charge (mAs) value for actual radiographs of female breasts combined with a measurement of compressed breast thickness provides information on absorbed dose values for actual radiographs. An approximately 50 mm thick poly(methyl methacrylate) phantom can be used for determination of absorbed dose in mammography. (author)

  7. 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.

  8. New quantities in radiation protection and conversion coefficients

    International Nuclear Information System (INIS)

    1986-01-01

    Four new quantities have been proposed by the ICRP for use in radiation protection from external sources, i.e. the ambient dose equivalent, the directional dose equivalent, the individual dose equivalent (penetrating), and the individual dose equivalent (superficial). These quantities are briefly described together with two new concepts of expanded and aligned fields. The BCRU recommends that these quantities should be adopted for use in the UK together with conversion coefficients when re-calibrating existing instruments, reporting the results of measurements and designing instruments. (UK)

  9. 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