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Sample records for dose conversion factor

  1. Dose conversion factors

    International Nuclear Information System (INIS)

    Kocher, D.C.; Eckerman, K.F.

    1992-01-01

    The following is discussed in this report: concepts and quantities used in calculating radiation dose from internal and external exposure. Tabulations of dose conversion factor for internal and external exposure to radionuclides. Dose conversion factors give dose per unit intake (internal) or dose per unit concentration in environment (external). Intakes of radionuclides for internal exposure and concentrations of radionuclides in environment for external exposure are assumed to be known. Intakes and concentrations are obtained, e.g., from analyses of environmental transport and exposure pathways. differences between dosimetry methods for radionuclides and hazardous chemicals are highlighted

  2. Derivation of dose conversion factors for tritium

    Energy Technology Data Exchange (ETDEWEB)

    Killough, G. G.

    1982-03-01

    For a given intake mode (ingestion, inhalation, absorption through the skin), a dose conversion factor (DCF) is the committed dose equivalent to a specified organ of an individual per unit intake of a radionuclide. One also may consider the effective dose commitment per unit intake, which is a weighted average of organ-specific DCFs, with weights proportional to risks associated with stochastic radiation-induced fatal health effects, as defined by Publication 26 of the International Commission on Radiological Protection (ICRP). This report derives and tabulates organ-specific dose conversion factors and the effective dose commitment per unit intake of tritium. These factors are based on a steady-state model of hydrogen in the tissues of ICRP's Reference Man (ICRP Publication 23) and equilibrium of specific activities between body water and other tissues. The results differ by 27 to 33% from the estimate on which ICRP Publication 30 recommendations are based. The report also examines a dynamic model of tritium retention in body water, mineral bone, and two compartments representing organically-bound hydrogen. This model is compared with data from human subjects who were observed for extended periods. The manner of combining the dose conversion factors with measured or model-predicted levels of contamination in man's exposure media (air, drinking water, soil moisture) to estimate dose rate to an individual is briefly discussed.

  3. Derivation of dose conversion factors for tritium

    International Nuclear Information System (INIS)

    Killough, G.G.

    1982-03-01

    For a given intake mode (ingestion, inhalation, absorption through the skin), a dose conversion factor (DCF) is the committed dose equivalent to a specified organ of an individual per unit intake of a radionuclide. One also may consider the effective dose commitment per unit intake, which is a weighted average of organ-specific DCFs, with weights proportional to risks associated with stochastic radiation-induced fatal health effects, as defined by Publication 26 of the International Commission on Radiological Protection (ICRP). This report derives and tabulates organ-specific dose conversion factors and the effective dose commitment per unit intake of tritium. These factors are based on a steady-state model of hydrogen in the tissues of ICRP's Reference Man (ICRP Publication 23) and equilibrium of specific activities between body water and other tissues. The results differ by 27 to 33% from the estimate on which ICRP Publication 30 recommendations are based. The report also examines a dynamic model of tritium retention in body water, mineral bone, and two compartments representing organically-bound hydrogen. This model is compared with data from human subjects who were observed for extended periods. The manner of combining the dose conversion factors with measured or model-predicted levels of contamination in man's exposure media (air, drinking water, soil moisture) to estimate dose rate to an individual is briefly discussed

  4. Proposal concerning the absorbed dose conversion factor

    Energy Technology Data Exchange (ETDEWEB)

    Shiragai, A [National Inst. of Radiological Sciences, Chiba (Japan)

    1978-03-01

    New definitions of the absorbed dose conversion factors Csub(lambda) and Csub(E) are proposed. The absorbed dose in water is given by the product of absorbed dose conversion factor, exposure calibration factor, ionisation chamber reading, cap displacement correction factor and perturbation correction factor. At exposure calibration the material of the build-up cap must be the same as that of the chamber wall. An ionisation chamber of which the wall material is water-equivalent or air-equivalent may be used. In the latter case the wall must be thin. For these two cases absorbed dose conversion factors are introduced and it is recommended that either of the two sets should be adopted. Furthermore, if the chamber wall is neither water- nor air-equivalent, the factor by which these currently defined values should be multiplied is also given: again the wall must be thin. The ICRU definitions of Csub(lambda) and Csub(E) are inconsistent, as recently pointed out, while the definitions presented here are consistent.

  5. External dose conversion factor from canal water

    International Nuclear Information System (INIS)

    Bhargava, Pradeep; Chitra, S.; Mhatre, Arti S.; Singh, Kapil Deo

    2016-01-01

    External dose needs to be estimated for the radioactivity discharged into the canal, as it constitutes one of the pathways of exposure to the public. Two activities are considered here: i) a walk along the bank of the canal ii) and the walk on the bridge. A concentration of 1 Bq/l is assumed here for the gross beta activity for the estimation of the dose conversion factor. A canal of width 14.39 m and the depth of 2.5 m is considered for this study. Length of the canal is taken to be infinite. Canal side wall is assumed to be the 25 cm thick concrete. Two points are selected, one on the bank, and the second on a bridge 1 m above the top surface of canal water. Dose Conversion factors for the person moving on the Bridge (at one meter above the water surface) and standing on bank of canal is estimated by using the QAD CG code for 137 Cs. Dose conversion factors for the location mentioned above are found to be 1.11E-10 Sv/hr/(Bq/l) and 1.55 E-11 Sv/hr/(Bq/l) for bridge and bank of canal respectively. (author)

  6. Nominal Performance Biosphere Dose Conversion Factor Analysis

    Energy Technology Data Exchange (ETDEWEB)

    M.A. Wasiolek

    2003-07-25

    This analysis report is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the Total System Performance Assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis report describes the development of biosphere dose conversion factors (BDCFs) for the groundwater exposure scenario, and the development of conversion factors for assessing compliance with the groundwater protection standard. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of two reports that develop biosphere BDCFs, which are input parameters for the TSPA model. The ''Biosphere Model Report'' (BSC 2003 [DIRS 164186]) describes in detail the ERMYN conceptual model and mathematical model. The input parameter reports (BSC 2003 [DIRS 160964]; BSC 2003 [DIRS 160965]; BSC 2003 [DIRS 160976]; BSC 2003 [DIRS 161239]; BSC 2003 [DIRS 161241]) contain detailed description of the model input parameters. This report describes biosphere model calculations and their output, the BDCFs, for the groundwater exposure scenario. The objectives of this analysis are to develop BDCFs and conversion factors for the TSPA. The BDCFs will be used in performance assessment for calculating annual doses for a given concentration of radionuclides in groundwater. The conversion factors will be used for calculating gross alpha particle activity in groundwater and the annual dose from beta- and photon-emitting radionuclides.

  7. Nominal Performance Biosphere Dose Conversion Factor Analysis

    International Nuclear Information System (INIS)

    M. Wasiolek

    2004-01-01

    This analysis report is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the Total System Performance Assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis report describes the development of biosphere dose conversion factors (BDCFs) for the groundwater exposure scenario, and the development of conversion factors for assessing compliance with the groundwater protection standard. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of two reports that develop biosphere BDCFs, which are input parameters for the TSPA-LA model. The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the ERMYN conceptual model and mathematical model. The input parameter reports, shown to the right of the ''Biosphere Model Report'' in Figure 1-1, contain detailed description of the model input parameters, their development, and the relationship between the parameters and specific features events and processes (FEPs). This report describes biosphere model calculations and their output, the BDCFs, for the groundwater exposure scenario. The objectives of this analysis are to develop BDCFs for the groundwater exposure scenario for the three climate states considered in the TSPA-LA as well as conversion factors for evaluating compliance with the groundwater protection standard. The BDCFs will be used in performance assessment for calculating all-pathway annual doses for a given concentration of radionuclides in groundwater. The conversion factors will be used for calculating gross alpha particle activity in groundwater and the annual dose

  8. Nominal Performance Biosphere Dose Conversion Factor Analysis

    Energy Technology Data Exchange (ETDEWEB)

    M.A. Wasiolek

    2005-04-28

    This analysis report is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the Total System Performance Assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis report describes the development of biosphere dose conversion factors (BDCFs) for the groundwater exposure scenario, and the development of conversion factors for assessing compliance with the groundwater protection standards. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of two reports that develop BDCFs, which are input parameters for the TSPA-LA model. The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the ERMYN conceptual model and mathematical model. The input parameter reports, shown to the right of the ''Biosphere Model Report'' in Figure 1-1, contain detailed description of the model input parameters, their development, and the relationship between the parameters and specific features events and processes (FEPs). This report describes biosphere model calculations and their output, the BDCFs, for the groundwater exposure scenario. This analysis receives direct input from the outputs of the ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) and the five analyses that develop parameter values for the biosphere model (BSC 2005 [DIRS 172827]; BSC 2004 [DIRS 169672]; BSC 2004 [DIRS 169673]; BSC 2004 [DIRS 169458]; BSC 2004 [DIRS 169459]). The results of this report are further analyzed in the ''Biosphere Dose Conversion Factor Importance and Sensitivity Analysis

  9. Nominal Performance Biosphere Dose Conversion Factor Analysis

    International Nuclear Information System (INIS)

    M.A. Wasiolek

    2005-01-01

    This analysis report is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the Total System Performance Assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis report describes the development of biosphere dose conversion factors (BDCFs) for the groundwater exposure scenario, and the development of conversion factors for assessing compliance with the groundwater protection standards. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of two reports that develop BDCFs, which are input parameters for the TSPA-LA model. The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the ERMYN conceptual model and mathematical model. The input parameter reports, shown to the right of the ''Biosphere Model Report'' in Figure 1-1, contain detailed description of the model input parameters, their development, and the relationship between the parameters and specific features events and processes (FEPs). This report describes biosphere model calculations and their output, the BDCFs, for the groundwater exposure scenario. This analysis receives direct input from the outputs of the ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) and the five analyses that develop parameter values for the biosphere model (BSC 2005 [DIRS 172827]; BSC 2004 [DIRS 169672]; BSC 2004 [DIRS 169673]; BSC 2004 [DIRS 169458]; BSC 2004 [DIRS 169459]). The results of this report are further analyzed in the ''Biosphere Dose Conversion Factor Importance and Sensitivity Analysis'' (Figure 1-1). The objectives of this analysis are to develop BDCFs for the

  10. DISRUPTIVE EVENT BIOSPHERE DOSE CONVERSION FACTOR ANALYSIS

    International Nuclear Information System (INIS)

    M.A. Wasiolek

    2005-01-01

    This analysis report is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the total system performance assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis report describes the development of biosphere dose conversion factors (BDCFs) for the volcanic ash exposure scenario, and the development of dose factors for calculating inhalation dose during volcanic eruption. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of two reports that develop biosphere BDCFs, which are input parameters for the TSPA model. The Biosphere Model Report (BSC 2004 [DIRS 169460]) describes in detail the ERMYN conceptual model and mathematical model. The input parameter reports, shown to the right of the Biosphere Model Report in Figure 1-1, contain detailed descriptions of the model input parameters, their development and the relationship between the parameters and specific features, events and processes (FEPs). This report describes biosphere model calculations and their output, the BDCFs, for the volcanic ash exposure scenario. This analysis receives direct input from the outputs of the ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) and from the five analyses that develop parameter values for the biosphere model (BSC 2005 [DIRS 172827]; BSC 2004 [DIRS 169672]; BSC 2004 [DIRS 169673]; BSC 2004 [DIRS 169458]; and BSC 2004 [DIRS 169459]). The results of this report are further analyzed in the ''Biosphere Dose Conversion Factor Importance and Sensitivity Analysis'' (Figure 1-1). The objective of this analysis was to develop the BDCFs for the volcanic

  11. Nominal Performance Biosphere Dose Conversion Factor Analysis

    Energy Technology Data Exchange (ETDEWEB)

    M. Wasiolek

    2004-09-08

    This analysis report is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the Total System Performance Assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis report describes the development of biosphere dose conversion factors (BDCFs) for the groundwater exposure scenario, and the development of conversion factors for assessing compliance with the groundwater protection standard. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of two reports that develop biosphere BDCFs, which are input parameters for the TSPA-LA model. The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the ERMYN conceptual model and mathematical model. The input parameter reports, shown to the right of the ''Biosphere Model Report'' in Figure 1-1, contain detailed description of the model input parameters, their development, and the relationship between the parameters and specific features events and processes (FEPs). This report describes biosphere model calculations and their output, the BDCFs, for the groundwater exposure scenario. The objectives of this analysis are to develop BDCFs for the groundwater exposure scenario for the three climate states considered in the TSPA-LA as well as conversion factors for evaluating compliance with the groundwater protection standard. The BDCFs will be used in performance assessment for calculating all-pathway annual doses for a given concentration of radionuclides in groundwater. The conversion factors will be used for calculating gross alpha particle

  12. Disruptive Event Biosphere Dose Conversion Factor Analysis

    Energy Technology Data Exchange (ETDEWEB)

    M. A. Wasiolek

    2003-07-21

    This analysis report, ''Disruptive Event Biosphere Dose Conversion Factor Analysis'', is one of the technical reports containing documentation of the ERMYN (Environmental Radiation Model for Yucca Mountain Nevada) biosphere model for the geologic repository at Yucca Mountain, its input parameters, and the application of the model to perform the dose assessment for the repository. The biosphere model is one of a series of process models supporting the Total System Performance Assessment (TSPA) for the Yucca Mountain repository. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of the two reports that develop biosphere dose conversion factors (BDCFs), which are input parameters for the TSPA model. The ''Biosphere Model Report'' (BSC 2003 [DIRS 164186]) describes in detail the conceptual model as well as the mathematical model and lists its input parameters. Model input parameters are developed and described in detail in five analysis report (BSC 2003 [DIRS 160964], BSC 2003 [DIRS 160965], BSC 2003 [DIRS 160976], BSC 2003 [DIRS 161239], and BSC 2003 [DIRS 161241]). The objective of this analysis was to develop the BDCFs for the volcanic ash exposure scenario and the dose factors (DFs) for calculating inhalation doses during volcanic eruption (eruption phase of the volcanic event). The volcanic ash exposure scenario is hereafter referred to as the volcanic ash scenario. For the volcanic ash scenario, the mode of radionuclide release into the biosphere is a volcanic eruption through the repository with the resulting entrainment of contaminated waste in the tephra and the subsequent atmospheric transport and dispersion of contaminated material in

  13. Disruptive Event Biosphere Dose Conversion Factor Analysis

    International Nuclear Information System (INIS)

    M. A. Wasiolek

    2003-01-01

    This analysis report, ''Disruptive Event Biosphere Dose Conversion Factor Analysis'', is one of the technical reports containing documentation of the ERMYN (Environmental Radiation Model for Yucca Mountain Nevada) biosphere model for the geologic repository at Yucca Mountain, its input parameters, and the application of the model to perform the dose assessment for the repository. The biosphere model is one of a series of process models supporting the Total System Performance Assessment (TSPA) for the Yucca Mountain repository. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of the two reports that develop biosphere dose conversion factors (BDCFs), which are input parameters for the TSPA model. The ''Biosphere Model Report'' (BSC 2003 [DIRS 164186]) describes in detail the conceptual model as well as the mathematical model and lists its input parameters. Model input parameters are developed and described in detail in five analysis report (BSC 2003 [DIRS 160964], BSC 2003 [DIRS 160965], BSC 2003 [DIRS 160976], BSC 2003 [DIRS 161239], and BSC 2003 [DIRS 161241]). The objective of this analysis was to develop the BDCFs for the volcanic ash exposure scenario and the dose factors (DFs) for calculating inhalation doses during volcanic eruption (eruption phase of the volcanic event). The volcanic ash exposure scenario is hereafter referred to as the volcanic ash scenario. For the volcanic ash scenario, the mode of radionuclide release into the biosphere is a volcanic eruption through the repository with the resulting entrainment of contaminated waste in the tephra and the subsequent atmospheric transport and dispersion of contaminated material in the biosphere. The biosphere process

  14. Disruptive Event Biosphere Dose Conversion Factor Analysis

    Energy Technology Data Exchange (ETDEWEB)

    M. Wasiolek

    2004-09-08

    This analysis report is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the total system performance assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis report describes the development of biosphere dose conversion factors (BDCFs) for the volcanic ash exposure scenario, and the development of dose factors for calculating inhalation dose during volcanic eruption. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of two reports that develop biosphere BDCFs, which are input parameters for the TSPA model. The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the ERMYN conceptual model and mathematical model. The input parameter reports, shown to the right of the Biosphere Model Report in Figure 1-1, contain detailed descriptions of the model input parameters, their development and the relationship between the parameters and specific features, events and processes (FEPs). This report describes biosphere model calculations and their output, the BDCFs, for the volcanic ash exposure scenario. This analysis receives direct input from the outputs of the ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) and from the five analyses that develop parameter values for the biosphere model (BSC 2004 [DIRS 169671]; BSC 2004 [DIRS 169672]; BSC 2004 [DIRS 169673]; BSC 2004 [DIRS 169458]; and BSC 2004 [DIRS 169459]). The results of this report are further analyzed in the ''Biosphere Dose Conversion Factor Importance and Sensitivity Analysis''. The objective of this

  15. Disruptive Event Biosphere Dose Conversion Factor Analysis

    International Nuclear Information System (INIS)

    M. Wasiolek

    2004-01-01

    This analysis report is one of the technical reports containing documentation of the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the total system performance assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis report describes the development of biosphere dose conversion factors (BDCFs) for the volcanic ash exposure scenario, and the development of dose factors for calculating inhalation dose during volcanic eruption. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and provides an understanding of how this analysis report contributes to biosphere modeling. This report is one of two reports that develop biosphere BDCFs, which are input parameters for the TSPA model. The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the ERMYN conceptual model and mathematical model. The input parameter reports, shown to the right of the Biosphere Model Report in Figure 1-1, contain detailed descriptions of the model input parameters, their development and the relationship between the parameters and specific features, events and processes (FEPs). This report describes biosphere model calculations and their output, the BDCFs, for the volcanic ash exposure scenario. This analysis receives direct input from the outputs of the ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) and from the five analyses that develop parameter values for the biosphere model (BSC 2004 [DIRS 169671]; BSC 2004 [DIRS 169672]; BSC 2004 [DIRS 169673]; BSC 2004 [DIRS 169458]; and BSC 2004 [DIRS 169459]). The results of this report are further analyzed in the ''Biosphere Dose Conversion Factor Importance and Sensitivity Analysis''. The objective of this analysis was to develop the BDCFs for the volcanic ash

  16. Nominal Performance Biosphere Dose Conversion Factor Analysis

    International Nuclear Information System (INIS)

    Wasiolek, M.

    2000-01-01

    The purpose of this report was to document the process leading to development of the Biosphere Dose Conversion Factors (BDCFs) for the postclosure nominal performance of the potential repository at Yucca Mountain. BDCF calculations concerned twenty-four radionuclides. This selection included sixteen radionuclides that may be significant nominal performance dose contributors during the compliance period of up to 10,000 years, five additional radionuclides of importance for up to 1 million years postclosure, and three relatively short-lived radionuclides important for the human intrusion scenario. Consideration of radionuclide buildup in soil caused by previous irrigation with contaminated groundwater was taken into account in the BDCF development. The effect of climate evolution, from the current arid conditions to a wetter and cooler climate, on the BDCF values was evaluated. The analysis included consideration of different exposure pathway's contribution to the BDCFs. Calculations of nominal performance BDCFs used the GENII-S computer code in a series of probabilistic realizations to propagate the uncertainties of input parameters into the output. BDCFs for the nominal performance, when combined with the concentrations of radionuclides in groundwater allow calculation of potential radiation doses to the receptor of interest. Calculated estimates of radionuclide concentration in groundwater result from the saturated zone modeling. The integration of the biosphere modeling results (BDCFs) with the outcomes of the other component models is accomplished in the Total System Performance Assessment (TSPA) to calculate doses to the receptor of interest from radionuclides postulated to be released to the environment from the potential repository at Yucca Mountain

  17. Conversion Factors for Predicting Unshielded Dose Rates in Shielded Waste

    International Nuclear Information System (INIS)

    Clapham, M.; Seamans Jr, J.V.; Arbon, R.E.

    2009-01-01

    This document describes the methodology developed and used by the Advanced Mixed Waste Treatment Project for determining the activity content and the unshielded surface dose rate for lead lined containers contaminated with transuranic waste. Several methods were investigated: - Direct measurement of the dose rate after removing the shielding. - Use of a MicroShield R derived dose conversion factor, (mRem/hr unshielded )/(mRem/hr shielded ), applied to the measured surface dose rate to estimate the unshielded surface dose rate. - Use of a MicroShield R derived activity conversion factor, mRem/hr unshielded /Ci, applied to the measured activity to estimate the unshielded dose rate. - Use of an empirically derived activity conversion factor, mRem/hr unshielded /Ci, applied to the measured activity to estimate the unshielded dose rate. The last approach proved to be the most efficacious by using a combination of nondestructive assay and empirically defined dose rate conversion factors. Empirically derived conversion factors were found to be highly dependent upon the matrix of the waste. Use of conversion factors relied on activity values corrected to address the presence of a lead liner. (authors)

  18. Estimates of external dose-rate conversion factors and internal dose conversion factors for selected radionuclides released from fusion facilities

    Energy Technology Data Exchange (ETDEWEB)

    Homma, Toshimitsu; Togawa, Orihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-11-01

    This report provides a tabulation of both external dose-rate conversion factors and internal dose conversion factors using radioactive decay data in the updated Evaluated Nuclear Structure Data File (ENSDF) for selected 26 radionuclides and all their daughter radionuclides of potential importance in safety assessments of fusion facilities. The external dose-rate conversion factors for 21 target organs are tabulated for three exposure modes that are immersion in contaminated air, irradiation at a height of 1 m above a contaminated ground surface and immersion contaminated water. For internal exposure, committed dose equivalents, based on the methodology of ICRP Publication 30, in the same target organs per intake of unit activity are given for the inhalation and ingestion exposure pathways. The data presented here is intended to be generally used for safety assessments of fusion reactors. Comparisons of external effective dose-rate conversion factors and committed effective dose equivalents are made with the previous data from the independent data bases to provide quality assurance on our calculated results. There is generally good agreement among data from the independent data bases. The differences in the values of both effective dose-rate and dose conversion factors appeared are primarily due to differences in calculational methodology, the use of different radioactive decay data, and compilation errors. (author)

  19. External dose-rate conversion factors for calculation of dose to the public

    Energy Technology Data Exchange (ETDEWEB)

    1988-07-01

    This report presents a tabulation of dose-rate conversion factors for external exposure to photons and electrons emitted by radionuclides in the environment. This report was prepared in conjunction with criteria for limiting dose equivalents to members of the public from operations of the US Department of Energy (DOE). The dose-rate conversion factors are provided for use by the DOE and its contractors in performing calculations of external dose equivalents to members of the public. The dose-rate conversion factors for external exposure to photons and electrons presented in this report are based on a methodology developed at Oak Ridge National Laboratory. However, some adjustments of the previously documented methodology have been made in obtaining the dose-rate conversion factors in this report. 42 refs., 1 fig., 4 tabs.

  20. Radon: characteristics in air and dose conversion factors

    International Nuclear Information System (INIS)

    Porstendoerfer, J.; Reineking, A.

    1998-01-01

    The dose conversion factor (DCF) which gives the relationship between effective dose and potential alpha energy concentration of inhaled short-lived radon decay products is calculated with a dosimetric approach. The calculations are based on a lung dose model with a structure that is related to the new recommended ICRP respiratory tract model (ICRP 66). The characteristics of the radon decay products concerning the unattached fraction and the activity size distribution of the radon decay products are important input quantities for the calculation of DCF. The experimental data about these quantities obtained from measurements in homes, at work places, and in the free atmosphere near ground in the last past years are reported. The DCF fraction of the unattached (DCF u ) and aerosol-attached (DCF ae ) radon decay products for different places are presented, taking into account the measured characteristics. The influence of the unattached radon daughters on the dose conversion factor DCF u is reported and compared with the DCF ae of the aerosol fraction. (author)

  1. Ecosystem specific dose conversion factors for Aberg, Beberg and Ceberg

    International Nuclear Information System (INIS)

    Nordlinder, S.; Bergstroem, U.; Mathiasson, Lena

    1999-12-01

    The aim of this study was to calculate ecosystem specific dose conversion factors (EDFs) for three hypothetical sites, Aberg, Beberg and Ceberg, used in the safety analysis SR 97. The EDFs can, in combination with calculated releases of radionuclides from the geosphere, be used to illustrate relative differences in doses to the most exposed individual due to accidental leakage of radionuclides from a deep repository for spent nuclear fuel. Maps of the three sites were studied and subdivided into areas, which were characterised according to an earlier developed module system. For each of the identified modules, ecosystem transport and exposure model calculations were performed for release of 1 Bq per year during 10 000 years. 44 radionuclides contained within a deep repository for spent nuclear fuel were considered. A preliminary comparison of the EDFs for the three sites showed that the highest relative doses can be expected in Ceberg due to the high frequency of peat bog modules

  2. Biosphere dose conversion Factor Importance and Sensitivity Analysis

    International Nuclear Information System (INIS)

    M. Wasiolek

    2004-01-01

    This report presents importance and sensitivity analysis for the environmental radiation model for Yucca Mountain, Nevada (ERMYN). ERMYN is a biosphere model supporting the total system performance assessment (TSPA) for the license application (LA) for the Yucca Mountain repository. This analysis concerns the output of the model, biosphere dose conversion factors (BDCFs) for the groundwater, and the volcanic ash exposure scenarios. It identifies important processes and parameters that influence the BDCF values and distributions, enhances understanding of the relative importance of the physical and environmental processes on the outcome of the biosphere model, includes a detailed pathway analysis for key radionuclides, and evaluates the appropriateness of selected parameter values that are not site-specific or have large uncertainty

  3. Current status on preparation of dose conversion factors based on 1990 ICRP recommendations

    International Nuclear Information System (INIS)

    Yoshizawa, Michio

    1996-01-01

    The current status of arrangement of dose conversion factors for operational quantities are explained on the basis of 1995 ICRP-ICRU recommendations. The dose conversion factors of photon, neutron and electron were recommended by ICRP Publ. 74. It's contents are described. The relation between new dose conversion factors and the laws in connection with protecting radiation are explained. The dose conversion factors of 1 cm-, 3 mm- and 70 μm - dose equivalent which were introduced into the laws connected therewith in Japan are accepted the same values of ICRP Publ. 51 for photon and neutron. I mentioned the points of discussing about new dose conversion factors which are expected to be recommended. The laws have to show the dose conversion factors to be used by calculation and estimation of radiation shield, etc. The limit of energy of ICRU individual dose equivalent for photon is now until 1 MeV, but the value is insufficient and necessary to 10 MeV as same as the ambient dose equivalent in due consideration of atomic energy facilities. JAERI is preparing these dose conversion factors now. (S.Y.)

  4. Comparison of the two different standard flux-to-dose rate conversion factors

    International Nuclear Information System (INIS)

    Metghalchi, M.; Ashrafi, R.

    1983-01-01

    A very useful and simple way of obtaining the dose rate associated with neutron or photon fluxes is to multiply these fluxes by the appropriate flux-to-dose rate conversion factors. Two basic standard flux-to-dose rate conversion factors. are being used in all over the world, those recommended by the International Commission on Radiation Protection (ICRP) and the American National Standars (ANS). The purpose of this paper is to compare these two standard with each other. The comparison proved that the dose rate associated with a specific neutron flux, obtained by the ANS flux-to-dose rate conversion factors is usually higher than those calculated by the ICRP's conversion factors. Whereas in the case of the photon, in all energies, the difference between the dose rates obtained by these two standard flux-to-dose rate conversion factors are noticeable, and the ANS results are higher than the ICRP ones. So, it should be noted that for a specific neutron or photon flux the dose rate obtained by the ANS flux-to-dose rate conversion factors are more conservative than those obtained by the ICRP's. Therefore, in order to establish a more reasonable new standard flux-to-dose rate conversion factors, more work should be done. (author)

  5. Calculation of dose conversion factors for doses in the fingernails to organ doses at external gamma irradiation in air

    International Nuclear Information System (INIS)

    Khailov, A.M.; Ivannikov, A.I.; Skvortsov, V.G.; Stepanenko, V.F.; Orlenko, S.P.; Flood, A.B.; Williams, B.B.; Swartz, H.M.

    2015-01-01

    Absorbed doses to fingernails and organs were calculated for a set of homogenous external gamma-ray irradiation geometries in air. The doses were obtained by stochastic modeling of the ionizing particle transport (Monte Carlo method) for a mathematical human phantom with arms and hands placed loosely along the sides of the body. The resulting dose conversion factors for absorbed doses in fingernails can be used to assess the dose distribution and magnitude in practical dose reconstruction problems. For purposes of estimating dose in a large population exposed to radiation in order to triage people for treatment of acute radiation syndrome, the calculated data for a range of energies having a width of from 0.05 to 3.5 MeV were used to convert absorbed doses in fingernails to corresponding doses in organs and the whole body as well as the effective dose. Doses were assessed based on assumed rates of radioactive fallout at different time periods following a nuclear explosion. - Highlights: • Elemental composition and density of nails were determined. • MIRD-type mathematical human phantom with arms and hands was created. • Organ doses and doses to nails were calculated for external photon exposure in air. • Effective dose and nail doses values are close for rotational and soil surface exposures.

  6. Calculation of dose-rate conversion factors for external exposure to photons and electrons

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1978-01-01

    Methods are presented for the calculation of dose-rate conversion factors for external exposure to photon and electron radiation from radioactive decay. A dose-rate conversion factor is defined as the dose-equivalent rate per unit radionuclide concentration. Exposure modes considered are immersion in contaminated air, immersion in contaminated water, and irradiation from a contaminated ground surface. For each radiation type and exposure mode, dose-rate conversion factors are derived for tissue-equivalent material at the body surface of an exposed individual. In addition, photon dose-rate conversion factors are estimated for 22 body organs. The calculations are based on the assumption that the exposure medium is infinite in extent and that the radionuclide concentration is uniform. The dose-rate conversion factors for immersion in contaminated air and water then follow from the requirement that all of the energy emitted in the radioactive decay is absorbed in the infinite medium. Dose-rate conversion factors for ground-surface exposure are calculated at a reference location above a smooth, infinite plane using the point-kernel integration method and known specific absorbed fractions for photons and electrons in air

  7. Evaluation of fluence to dose equivalent conversion factors for high energy radiations, (1)

    International Nuclear Information System (INIS)

    Sato, Osamu; Uehara, Takashi; Yoshizawa, Nobuaki; Iwai, Satoshi; Tanaka, Shun-ichi.

    1992-09-01

    Computer code system and basic data have been investigated for evaluating fluence to dose equivalent conversion factors for photons and neutrons up to 10 GeV. The present work suggested that the conversion factors would be obtained by incorporating effective quality factors of charged particles into the HERMES (High Energy Radiation Monte Carlo Elaborate System) code system. The effective quality factors for charged particles were calculated on the basis of the Q-L relationships specified in the ICRP Publication-60. (author)

  8. Dose conversion factors for inhalation applicable to the mining and milling of radioactive ores

    International Nuclear Information System (INIS)

    Hartley, B.M.

    1992-01-01

    The ICRP recommended revised dose limits for exposure to ionising radiation in November 1990. As well as reducing the annual occupational dose equivalent limit to an average of 20 mSv over 5 years, modified organ weighting factors were recommended, reflecting improved understanding of cancer risk factors for tissues and organs. The adjustment of weighting factors means that derived air concentrations conversion factors and annual limits on intake for exposure to airborne radionuclides are not simply modified by the ratio of the old to the new limits. A recalculation of these factors for radionuclides of interest in the mining and milling of radioactive ores is presented. A computer program for this purpose, based on the ICRP 30 inhalation model, is described. Rapid calculations of dose conversion factors are possible for the naturally occurring radionuclides in the 235 U, 238 U and 232 Th decay chains for which data are given in the supplements to ICRP 30. 7 refs., 12 tabs., 5 figs

  9. Neutron fluence-to-dose equivalent conversion factors: a comparison of data sets and interpolation methods

    International Nuclear Information System (INIS)

    Sims, C.S.; Killough, G.G.

    1983-01-01

    Various segments of the health physics community advocate the use of different sets of neutron fluence-to-dose equivalent conversion factors as a function of energy and different methods of interpolation between discrete points in those data sets. The major data sets and interpolation methods are used to calculate the spectrum average fluence-to-dose equivalent conversion factors for five spectra associated with the various shielded conditions of the Health Physics Research Reactor. The results obtained by use of the different data sets and interpolation methods are compared and discussed. (author)

  10. Landscape dose conversion factors used in the safety assessment SR-Site

    International Nuclear Information System (INIS)

    Avila, Rodolfo; Ekstroem, Per-Anders; Aastrand, Per-Gustav

    2010-12-01

    In this report two types of Dose Conversion Factors have been derived: i) a Landscape Dose Conversion Factor (LDF) that is applicable to continuous long-term releases to the biosphere at a constant rate, and ii) a Landscape Dose Conversion Factor for pulse releases (LDF pulse) that is applicable to a radionuclide release that reaches the biosphere in a pulse within years to hundreds of years. In SR-Site these Dose Factors are multiplied with modelled release rates or pulse releases from the geosphere to obtain dose estimates used in assessment of compliance with the regulatory risk criterion. The LDFs were calculated for three different periods of the reference glacial cycle; a period of submerged conditions following the deglaciation, the temperate period, and a prolonged period of periglacial conditions. Additionally, LDFs were calculated for the global warming climate case. The LDF pulse was calculated only for temperate climate conditions. The LDF and LDF pulse can be considered as Best Estimate values, which can be used in calculations of Best Estimate values of doses to a representative individual of the most exposed group from potential releases from a future repository. A systematic analysis of the effects of system, model and parameter uncertainties on the LDFs has been carried out. This analysis has shown that the use of the derived LDF would lead to cautious or realistic dose estimates. The models and methods that were used for derivation of the LDFs and LDF pulse are also described in this report

  11. Landscape dose conversion factors used in the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Rodolfo; Ekstroem, Per-Anders; Aastrand, Per-Gustav (Facilia AB (Sweden))

    2010-12-15

    In this report two types of Dose Conversion Factors have been derived: i) a Landscape Dose Conversion Factor (LDF) that is applicable to continuous long-term releases to the biosphere at a constant rate, and ii) a Landscape Dose Conversion Factor for pulse releases (LDF pulse) that is applicable to a radionuclide release that reaches the biosphere in a pulse within years to hundreds of years. In SR-Site these Dose Factors are multiplied with modelled release rates or pulse releases from the geosphere to obtain dose estimates used in assessment of compliance with the regulatory risk criterion. The LDFs were calculated for three different periods of the reference glacial cycle; a period of submerged conditions following the deglaciation, the temperate period, and a prolonged period of periglacial conditions. Additionally, LDFs were calculated for the global warming climate case. The LDF pulse was calculated only for temperate climate conditions. The LDF and LDF pulse can be considered as Best Estimate values, which can be used in calculations of Best Estimate values of doses to a representative individual of the most exposed group from potential releases from a future repository. A systematic analysis of the effects of system, model and parameter uncertainties on the LDFs has been carried out. This analysis has shown that the use of the derived LDF would lead to cautious or realistic dose estimates. The models and methods that were used for derivation of the LDFs and LDF pulse are also described in this report

  12. Calculation of neutron and gamma-ray flux-to-dose-rate conversion factors

    International Nuclear Information System (INIS)

    Kwon, S.G.; Lee, S.Y.; Yook, C.C.

    1981-01-01

    This paper presents flux-to-dose-rate conversion factors for neutrons and gamma rays based on the American National Standard Institute (ANSI) N666. These data are used to calculate the dose rate distribution of neutron and gamma ray in radiation fields. Neutron flux-to-dose-rate conversion factors for energies from 2.5 x 10 -8 to 20 MeV are presented; the corresponding energy range for gamma rays is 0.01 to 15 MeV. Flux-to-dose-rate conversion factors were calculated, under the assumption that radiation energy distribution has nonlinearity in the phantom, have different meaning from those values obtained by monoenergetic radiation. Especially, these values were determined with the cross section library. The flux-to-dose-rate conversion factors obtained in this work were in a good agreement to the values presented by ANSI. Those data will be useful for the radiation shielding analysis and the radiation dosimetry in the case of continuous energy distributions. (author)

  13. Estimating Effective Dose of Radiation From Pediatric Cardiac CT Angiography Using a 64-MDCT Scanner: New Conversion Factors Relating Dose-Length Product to Effective Dose.

    Science.gov (United States)

    Trattner, Sigal; Chelliah, Anjali; Prinsen, Peter; Ruzal-Shapiro, Carrie B; Xu, Yanping; Jambawalikar, Sachin; Amurao, Maxwell; Einstein, Andrew J

    2017-03-01

    The purpose of this study is to determine the conversion factors that enable accurate estimation of the effective dose (ED) used for cardiac 64-MDCT angiography performed for children. Anthropomorphic phantoms representative of 1- and 10-year-old children, with 50 metal oxide semiconductor field-effect transistor dosimeters placed in organs, underwent scanning performed using a 64-MDCT scanner with different routine clinical cardiac scan modes and x-ray tube potentials. Organ doses were used to calculate the ED on the basis of weighting factors published in 1991 in International Commission on Radiological Protection (ICRP) publication 60 and in 2007 in ICRP publication 103. The EDs and the scanner-reported dose-length products were used to determine conversion factors for each scan mode. The effect of infant heart rate on the ED and the conversion factors was also assessed. The mean conversion factors calculated using the current definition of ED that appeared in ICRP publication 103 were as follows: 0.099 mSv · mGy -1 · cm -1 , for the 1-year-old phantom, and 0.049 mSv · mGy -1 · cm -1 , for the 10-year-old phantom. These conversion factors were a mean of 37% higher than the corresponding conversion factors calculated using the older definition of ED that appeared in ICRP publication 60. Varying the heart rate did not influence the ED or the conversion factors. Conversion factors determined using the definition of ED in ICRP publication 103 and cardiac, rather than chest, scan coverage suggest that the radiation doses that children receive from cardiac CT performed using a contemporary 64-MDCT scanner are higher than the radiation doses previously reported when older chest conversion factors were used. Additional up-to-date pediatric cardiac CT conversion factors are required for use with other contemporary CT scanners and patients of different age ranges.

  14. Calculation of neutron fluence-to-dose conversion factors for extremities

    International Nuclear Information System (INIS)

    Stewart, R.D.; Harty, R.; McDonald, J.C.; Tanner, J.E.

    1993-04-01

    The Pacific Northwest Laboratory is developing a standard for the performance testing of personnel extremity dosimeters for the US Department of Energy. Part of this effort requires the calculation of neutron fluence-to-dose conversion factors for finger and wrist extremities. This study focuses on conversion factors for two types of extremity models: namely the polymethyl methacrylate (PMMA) phantom (as specified in the draft standard for performance testing of extremity dosimeters) and more realistic extremity models composed of tissue-and-bone. Calculations for each type of model are based on both bare and D 2 O-moderated 252 Cf sources. The results are then tabulated and compared with whole-body conversion factors. More appropriate energy-averaged quality factors for the extremity models have also been computed from the neutron fluence in 50 equally spaced energy bins with energies from 2.53 x 10 -8 to 15 MeV. Tabulated results show that conversion factors for both types of extremity phantom are 15 to 30% lower than the corresponcung whole-body phantom conversion factors for 252 Cf neutron sources. This difference in extremity and whole-body conversion factors is attributable to the proportionally smaller amount of back-scattering that occurs in the extremity phantoms compared with whole-body phantoms

  15. Comparison of Radiation Dose Rates with the Flux to Dose Conversion Factors Recommended in ICRP-74 and ICRP-116

    International Nuclear Information System (INIS)

    Jeong, Hae Sun; Kil, A Reum; Lee, Jo Eun; Jeong, Hyo Joon; Kim, Eun Han; Han, Moon Hee; Hwang, Won Tae

    2016-01-01

    The evaluation of radiation shielding has been performed for the design and maintenance of various facilities using radioactive sources such as nuclear fuel, accelerator, and radionuclide. The conversion of flux to dose mainly used in nuclear and radiation fields has been generally made with the dose coefficients presented in ICRP Publication 74 (ICRP- 74), which are produced based on ICRP Publication 60. On the other hand, ICRP Publication 116 (ICRP-116), which adopts the protection system of ICRP Publication 103, has recently been published and provides the dose conversion coefficients calculated with a variety of Monte Carlo codes. The coefficients have more than an update of those in ICRP-74, including new particle types and a greatly expanded energy range. In this study, a shielding evaluation of a specific container for neutron and gamma sources was performed with the MCNP6 code. The dose rates from neutron and gamma-ray sources were calculated using the MCNP6 codes, and these results were based on the flux to dose conversion factors recommended in ICRP-74 and ICRP-116. As a result, the dose rates evaluated with ICRP-74 were generally shown higher than those with ICRP-116. For neutrons, the difference is mainly occurred by the decrease of radiation weighting factors in a part of energy ranges in the ICRP-116 recommendations. For gamma-rays, the ICRP-74 recommendation applied with the kerma approximation leads to overestimated results than the other assessment

  16. Internal dose conversion factors for calculation of dose to the public

    International Nuclear Information System (INIS)

    1988-07-01

    This publication contains 50-year committed dose equivalent factors, in tabular form. The document is intended to be used as the primary reference by the US Department of Energy (DOE) and its contractors for calculating radiation dose equivalents for members of the public, resulting from ingestion or inhalation of radioactive materials. Its application is intended specifically for such materials released to the environment during routine DOE operations, except in those instances where compliance with 40 CFR 61 (National Emission Standards for Hazardous Air Pollutants) requires otherwise. However, the calculated values may be equally applicable to unusual releases or to occupational exposures. The use of these committed dose equivalent tables should ensure that doses to members of the public from internal exposures are calculated in a consistent manner at all DOE facilities

  17. Assessment of dose conversion factors in a generic biosphere of a Korea HLW repository

    International Nuclear Information System (INIS)

    Hwang, Y. S.; Park, J. B.; Kang, C. H.

    2002-01-01

    Radioactive species released from a waste repository migrate through engineered and natural barriers and eventually reach the biosphere. Once entered the biosphere, contaminants transport various exposure pathways and finally reach a human. In this study the full RES matrix explaining the key compartments in the biosphere and their interactions is introduced considering the characteristics of the Korean biosphere. Then the three exposure groups are identified based on the compartments of interest. The full exposure pathways and corresponding mathematical expression for mass transfer coefficients and etc are developed and applied to assess the dose conversion factors of nuclides for a specific exposure group. Dose conversion factors assessed in this study will be used for total system performance assessment of a potential Korean HLW repository

  18. Preliminary Assessment of ICRP Dose Conversion Factor Recommendations for Accident Analysis Applications

    International Nuclear Information System (INIS)

    Vincent, A.M.

    2002-01-01

    Accident analysis for U.S. Department of Energy (DOE) nuclear facilities is an integral part of the overall safety basis developed by the contractor to demonstrate facility operation can be conducted safely. An appropriate documented safety analysis for a facility discusses accident phenomenology, quantifies source terms arising from postulated process upset conditions, and applies a standardized, internationally-recognized database of dose conversion factors (DCFs) to evaluate radiological conditions to offsite receptors

  19. Determination of photon conversion factors relating exposure and dose for several extremity phantom designs

    International Nuclear Information System (INIS)

    Roberson, P.L.; Eichner, F.N.; Reece, W.D.

    1986-09-01

    This report presents the results of measurements of dosimetric properties of simple extremity phantoms suitable for use in extremity dosimeter performance testing. Two sizes of phantoms were used in this study. One size represented the forearm or lower leg and the other size represented the finger or toe. For both phantom sizes, measurements were performed on solid plastic phantoms and on phantoms containing simulated bone material to determine the effect of backscattered radiations from the bone on the surface dose. Exposure-to-dose conversion factors (C/sub x/ factors) were determined for photon energies ranging from 16 to 1250 keV (average for 60 Co). The effect of the presence of a phantom was also measured for a 90 Sr/ 90 Y source. Significant differences in the measured C/sub x/ factors were found among the phantoms investigated. The factors for the finger-sized phantoms were uniformly less than for the arm-sized phantoms

  20. Experimental verification of the air kerma to absorbed dose conversion factor Cw,u.

    Science.gov (United States)

    Mijnheer, B J; Wittkämper, F W; Aalbers, A H; van Dijk, E

    1987-01-01

    In a recently published code of practice for the dosimetry of high-energy photon beams, the absorbed dose to water is determined using an ionization chamber having an air kerma calibration factor and applying the air kerma to absorbed dose conversion factor Cw,u. The consistency of these Cw,u values has been determined for four commonly employed types of ionization chambers in photon beams with quality varying between 60Co gamma-rays and 25 MV X-rays. Using a graphite calorimeter, Cw,u has been determined for a graphite-walled ionization chamber (NE 2561) for the same qualities. The values of Cw,u determined with the calorimeter are within the experimental uncertainty equal to Cw,u values determined according to any of the recent dosimetry protocols.

  1. Biosphere Dose Conversion Factors for Reasonably Maximally Exposed Individual and Average Member of Critical Group

    International Nuclear Information System (INIS)

    K. Montague

    2000-01-01

    The purpose of this calculation is to develop additional Biosphere Dose Conversion Factors (BDCFs) for a reasonably maximally exposed individual (RMEI) for the periods 10,000 years and 1,000,000 years after the repository closure. In addition, Biosphere Dose Conversion Factors for the average member of a critical group are calculated for those additional radionuclides postulated to reach the environment during the period after 10,000 years and up to 1,000,000 years. After the permanent closure of the repository, the engineered systems within the repository will eventually lose their abilities to contain radionuclide inventory, and the radionuclides will migrate through the geosphere and eventually enter the local water table moving toward inhabited areas. The primary release scenario is a groundwater well used for drinking water supply and irrigation, and this calculation takes these postulated releases and follows them through various pathways until they result in a dose to either a member of critical group or a reasonably maximally exposed individual. The pathways considered in this calculation include inhalation, ingestion, and direct exposure

  2. Cardiac-Specific Conversion Factors to Estimate Radiation Effective Dose From Dose-Length Product in Computed Tomography.

    Science.gov (United States)

    Trattner, Sigal; Halliburton, Sandra; Thompson, Carla M; Xu, Yanping; Chelliah, Anjali; Jambawalikar, Sachin R; Peng, Boyu; Peters, M Robert; Jacobs, Jill E; Ghesani, Munir; Jang, James J; Al-Khalidi, Hussein; Einstein, Andrew J

    2018-01-01

    This study sought to determine updated conversion factors (k-factors) that would enable accurate estimation of radiation effective dose (ED) for coronary computed tomography angiography (CTA) and calcium scoring performed on 12 contemporary scanner models and current clinical cardiac protocols and to compare these methods to the standard chest k-factor of 0.014 mSv·mGy -1 cm -1 . Accurate estimation of ED from cardiac CT scans is essential to meaningfully compare the benefits and risks of different cardiac imaging strategies and optimize test and protocol selection. Presently, ED from cardiac CT is generally estimated by multiplying a scanner-reported parameter, the dose-length product, by a k-factor which was determined for noncardiac chest CT, using single-slice scanners and a superseded definition of ED. Metal-oxide-semiconductor field-effect transistor radiation detectors were positioned in organs of anthropomorphic phantoms, which were scanned using all cardiac protocols, 120 clinical protocols in total, on 12 CT scanners representing the spectrum of scanners from 5 manufacturers (GE, Hitachi, Philips, Siemens, Toshiba). Organ doses were determined for each protocol, and ED was calculated as defined in International Commission on Radiological Protection Publication 103. Effective doses and scanner-reported dose-length products were used to determine k-factors for each scanner model and protocol. k-Factors averaged 0.026 mSv·mGy -1 cm -1 (95% confidence interval: 0.0258 to 0.0266) and ranged between 0.020 and 0.035 mSv·mGy -1 cm -1 . The standard chest k-factor underestimates ED by an average of 46%, ranging from 30% to 60%, depending on scanner, mode, and tube potential. Factors were higher for prospective axial versus retrospective helical scan modes, calcium scoring versus coronary CTA, and higher (100 to 120 kV) versus lower (80 kV) tube potential and varied among scanner models (range of average k-factors: 0.0229 to 0.0277 mSv·mGy -1 cm -1 ). Cardiac k-factors

  3. A feasibility assessment of calculation procedure with case study and the modification of dose conversion factor in STARDOSE

    International Nuclear Information System (INIS)

    Ko, H. S.; Jang, M.; Kim, S. H.; Kang, C. S.

    2003-01-01

    STARDOSE computer code is the designed code for which is calculated the dose of control room and off-site dose on design basis accident of nuclear power plant. Input files of STARDOSE are libfile1.txt which has decay constant and dose conversion factor, and input.dat which structurally expresses the real plant model by editor. It is given much advanced result with using newer dose conversion factor in libfile1.txt. In this study, therefore, case study is performed that is made input.dat file for LOCA and libfile1.txt which is included newer dose conversion factor and core inventory on APR-1400 and UCN 5 and 6. The result of case study is compared and analyzed

  4. The Thoron Issue: Monitoring Activities, Measuring Techniques and Dose Conversion Factors (invited paper)

    International Nuclear Information System (INIS)

    Nuccetelli, C.; Bochicchio, F.

    1998-01-01

    The health risk due to the presence of thoron indoors is usually neglected because of its generally low concentration in indoor environments, which is essentially caused by its short half-life. However, in certain not uncommon situations, such as when thorium-rich building materials are used, thoron ( 220 Rn) may represent a significant source of radioactive exposure. In recent years, renewed interest has led to more intensive monitoring of thoron gas and its decay products. A tentatively comprehensive summary of these measurement results and a review of the most innovative measurement techniques for 220 Rn are here presented. Finally, dose-exposure conversion factors currently used for thoron decay products are analysed, highlighting the poorer basis of such factors, when compared to those for radon. (author)

  5. Development and application of a complex numerical model and software for the computation of dose conversion factors for radon progenies.

    Science.gov (United States)

    Farkas, Árpád; Balásházy, Imre

    2015-04-01

    A more exact determination of dose conversion factors associated with radon progeny inhalation was possible due to the advancements in epidemiological health risk estimates in the last years. The enhancement of computational power and the development of numerical techniques allow computing dose conversion factors with increasing reliability. The objective of this study was to develop an integrated model and software based on a self-developed airway deposition code, an own bronchial dosimetry model and the computational methods accepted by International Commission on Radiological Protection (ICRP) to calculate dose conversion coefficients for different exposure conditions. The model was tested by its application for exposure and breathing conditions characteristic of mines and homes. The dose conversion factors were 8 and 16 mSv WLM(-1) for homes and mines when applying a stochastic deposition model combined with the ICRP dosimetry model (named PM-A model), and 9 and 17 mSv WLM(-1) when applying the same deposition model combined with authors' bronchial dosimetry model and the ICRP bronchiolar and alveolar-interstitial dosimetry model (called PM-B model). User friendly software for the computation of dose conversion factors has also been developed. The software allows one to compute conversion factors for a large range of exposure and breathing parameters and to perform sensitivity analyses. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Absorbed-dose beam quality conversion factors for cylindrical chambers in high energy photon beams.

    Science.gov (United States)

    Seuntjens, J P; Ross, C K; Shortt, K R; Rogers, D W

    2000-12-01

    Recent working groups of the AAPM [Almond et al., Med. Phys. 26, 1847 (1999)] and the IAEA (Andreo et al., Draft V.7 of "An International Code of Practice for Dosimetry based on Standards of Absorbed Dose to Water," IAEA, 2000) have described guidelines to base reference dosimetry of high energy photon beams on absorbed dose to water standards. In these protocols use is made of the absorbed-dose beam quality conversion factor, kQ which scales an absorbed-dose calibration factor at the reference quality 60Co to a quality Q, and which is calculated based on state-of-the-art ion chamber theory and data. In this paper we present the measurement and analysis of beam quality conversion factors kQ for cylindrical chambers in high-energy photon beams. At least three chambers of six different types were calibrated against the Canadian primary standard for absorbed dose based on a sealed water calorimeter at 60Co [TPR10(20)=0.572, %dd(10)x=58.4], 10 MV [TPR10(20)=0.682, %dd(10)x=69.6), 20 MV (TPR10(20)=0.758, %dd(10)x= 80.5] and 30 MV [TPR10(20) = 0.794, %dd(10)x= 88.4]. The uncertainty on the calorimetric determination of kQ for a single chamber is typically 0.36% and the overall 1sigma uncertainty on a set of chambers of the same type is typically 0.45%. The maximum deviation between a measured kQ and the TG-51 protocol value is 0.8%. The overall rms deviation between measurement and the TG-51 values, based on 20 chambers at the three energies, is 0.41%. When the effect of a 1 mm PMMA waterproofing sleeve is taken into account in the calculations, the maximum deviation is 1.1% and the overall rms deviation between measurement and calculation 0.48%. When the beam is specified using TPR10(20), and measurements are compared with kQ values calculated using the version of TG-21 with corrected formalism and data, differences are up to 1.6% when no sleeve corrections are taken into account. For the NE2571 and the NE2611A chamber types, for which the most literature data are

  7. Monte Carlo calculation of dose rate conversion factors for external exposure to photon emitters in soil

    CERN Document Server

    Clouvas, A; Antonopoulos-Domis, M; Silva, J

    2000-01-01

    The dose rate conversion factors D/sub CF/ (absorbed dose rate in air per unit activity per unit of soil mass, nGy h/sup -1/ per Bq kg/sup -1/) are calculated 1 m above ground for photon emitters of natural radionuclides uniformly distributed in the soil. Three Monte Carlo codes are used: 1) The MCNP code of Los Alamos; 2) The GEANT code of CERN; and 3) a Monte Carlo code developed in the Nuclear Technology Laboratory of the Aristotle University of Thessaloniki. The accuracy of the Monte Carlo results is tested by the comparison of the unscattered flux obtained by the three Monte Carlo codes with an independent straightforward calculation. All codes and particularly the MCNP calculate accurately the absorbed dose rate in air due to the unscattered radiation. For the total radiation (unscattered plus scattered) the D/sub CF/ values calculated from the three codes are in very good agreement between them. The comparison between these results and the results deduced previously by other authors indicates a good ag...

  8. Biosphere analysis - a complementary assessment of dose conversion factors for the Olkiluoto site

    International Nuclear Information System (INIS)

    Kylloenen, J.; Keto, V.

    2010-04-01

    The Olkiluoto site is currently the primary candidate for the final disposal site for spent nuclear fuel from the Olkiluoto and Loviisa NPPs. Safety analysis calculations must be performed to verify the compliance with the long-term safety requirements. The behaviour and distribution of radionuclides in the biosphere is of high importance in these calculations. The aim of this study was to perform a complementary assessment of dose conversion factors for the Olkiluoto site. Posiva has performed extensive analysis on the different ecosystems. In this work the biosphere analysis model of Fortum Nuclear Services (FNS) is used to give an independent estimate of biosphere dose conversion factors for the Olkiluoto site. The following nuclides are analysed: Cl-36, Ni-59, Se-79, Mo-93, Nb-94, Sn-126, I-129 and Cs-135. The FNS model is an equilibrium compartment model in which a steady annual release of 1 Bq of each radionuclide is distributed in different scenarios. The scenarios are the well scenario, which models a small agricultural ecosystem, the lake scenario which models a larger ecosystem with both agriculture and lake use, and sea and transition scenario, which models the behaviour of the radionuclides in marine environments. The scenarios are described and the transfer equations written for the lake scenario. The parameter values are taken from the FNS biosphere database, which has been used in the Finnish L/ILW waste repository safety analyses since mid 1990's. The results of the FNS analysis are compared to those presented in Posiva working report 2000-20 (POSIVA-WR-00-20). The results are of the same order of magnitude for all nuclides except I-129. Since the Posiva and FNS models were independently constructed, the results can be considered as convincing, and the compliance of the results give confidence to the modelling results. (orig.)

  9. Derivation of ingestion dose conversion factors for the U-238 decay series

    International Nuclear Information System (INIS)

    Jenkins, P.H.; Nicoll, R.M.; Doty, R.L.

    1978-01-01

    Dose conversion factors (DCF's) for the U-238 decay series were derived for use in the assessment of potential doses to man, through several ingestion pathways, by radionuclide deposition from radioactive airborne effluents. The methodology used, although similar to that outlined in the U.S. Nuclear Regulatory Commission's Regulatory Guide 1.109, is complicated by consideration of the ingrowth of decay products. Eight ingestion pathways were considered: (1) fresh vegetables, (2) stored vegetables, (3) milk from cows that eat pasture grass, (4) milk from cows that eat stored feed, (5) goat milk - pasture grass, (6) goat milk - stored feed, (7) beef - pasture grass, and (8) beef - stored feed. Radionuclide deposition was assumed to occur for the entire operational lifetime of the facility. Because the expected operational lifetime may vary from facility to facility, DCF's were calculated for six lifetimes: 10, 15, 20, 25, 30, and 35 years. DCF's were calculated for each of 13 'parent' nuclides in the decay series, with each DCF considering the ingrowth of all subsequent nuclides in the series. The methodology used to derive the DCF's is detailed, and DCF's normalized to a deposition rate of the parent nuclide of 1 μCi m -2 s -1 are reported. (author)

  10. Effective dose per unit kerma-area product conversion factors in adults undergoing modified barium swallow studies

    International Nuclear Information System (INIS)

    Shaw Bonilha, Heather; Wilmskoetter, Janina; Tipnis, Sameer V.; Martin-Harris, Bonnie; Huda, Walter

    2017-01-01

    This study presents an investigation of adult effective dose (E) per unit Kerma-Area Product (KAP) in Modified Barium Swallow Study (MBSS) examinations. PC program for X-ray Monte Carlo (version 2.0.1) was used to calculate patient organ doses during MBSS examinations, which used combined to generate effective dose. Normalized patient doses were obtained by dividing the effective dose (mSv) by the incident KAP (Gy.cm 2 ). Five standard projections were studied and the importance of X-ray beam size and in patient size (body mass index) were investigated. Lateral projections had an average E/ KAP conversion factor of 0.19 ± 0.04 mSv/Gy.cm 2 . The average E/KAP was highest for upper gastrointestinal (GI) anterior- posterior projections (0.27 ± 0.04 mSv/Gy.cm 2 ) and lowest for upper GI posterior-anterior projections (0.09 ± 0.03 mSv/ Gy.cm 2 ). E/KAP always increased with increasing filtration and/or X-ray tube voltage. Reducing the X-ray beam cross-sectional area increased the E/KAP conversion factors. Small patients have the E/KAP conversion factors that are twice those of a standard adult. Conversion factors for effective dose of adult patients undergoing MBSS examinations must account for X-ray beam projection, beam quality (kV and filtration), image size and patient size. (authors)

  11. Conversion factors for the ICRU dose equivalent quantities for calibrating radiation dosemeters

    International Nuclear Information System (INIS)

    Grosswendt, B.; Hohlfeld, K.; Kramer, H.M.; Selbach, H.J.

    1985-02-01

    Report describing the application of conversion factors for monoenergetic photon radiation and for X and gamma reference radiation used for dosemeter calibration with the aid of spherical or rectangular phantoms (environmental and individual monitoring). (DG) [de

  12. Application of the dose conversion factor for a NaI(Tl) detector to the radwaste drum assay

    International Nuclear Information System (INIS)

    Ji, Young-Yong; Hong, Dae-Seok; Kim, Tae-Kuk; Kwak, Kyung-Kil; Ryu, Woo-Seog

    2011-01-01

    The dose-to-curie (DTC) conversion method has been known that there could be extremely high uncertainty associated with establishing the radioactivity of gamma emitters in a drum. However, the DTC conversion method is still an effective assay method to calculate the radioisotope inventory because of the simple and easy procedures to be applied. In order to make the DTC conversion method practical, numerous assumptions and limitations placed on its use. These assumptions and limitations are related to the dose rate measurement and the relative abundance of gamma emitters in a drum. However, these two variables were generally obtained from the different detection mechanisms even using the different radwaste each other. Unfortunately, that expanded the limitation of using the DTC conversion method. In order to obtain two variables in a drum to be assayed at once, the dose conversion factor for a NaI(Tl) detector was first calculated from the MCNP code. The pulse height spectrum from a simulated drum inserted into a standard source was measured by a NaI(Tl) detector, and then, two variables were calculated from the dose conversion factor and the net count rate of detected gamma emitters in the pulse height spectrum.

  13. Electron dose-rate conversion factors for external exposure of the skin from uniformly deposited activity on the body surface

    International Nuclear Information System (INIS)

    Kocher, D.C.; Eckerman, K.F.

    1987-01-01

    Dose-rate conversion factors have been calculated for external exposure of the skin from electrons emitted by sources that are deposited uniformly on the body surface. The dose-rate factors are obtained from electron scaled point kernels developed by Berger. The dose-rate factors are calculated at depths of 4, 8, and 40 mg cm-2 below the body surface as recommended by Whitton, and at a depth of 7 mg cm-2 as recommended in ICRP Publication 26 (ICRP77). The dependence of the dose-rate factors at selected depths on the energy of the emitted electrons is displayed. The dose-rate factors for selected radionuclides of potential importance in radiological assessments are tabulated

  14. Skin dose rate conversion factors after contamination with radiopharmaceuticals: influence of contamination area, epidermal thickness and percutaneous absorption

    International Nuclear Information System (INIS)

    Covens, P; Berus, D; Caveliers, V; Struelens, L; Vanhavere, F; Verellen, D

    2013-01-01

    Skin contamination with radiopharmaceuticals can occur during biomedical research and daily nuclear medicine practice as a result of accidental spills, after contact with bodily fluids of patients or by inattentively touching contaminated materials. Skin dose assessment should be carried out by repeated quantification to map the course of the contamination together with the use of appropriate skin dose rate conversion factors. Contamination is generally characterised by local spots on the palmar surface of the hand and complete decontamination is difficult as a result of percutaneous absorption. This specific issue requires special consideration as to the skin dose rate conversion factors as a measure for the absorbed dose rate to the basal layer of the epidermis. In this work we used Monte Carlo simulations to study the influence of the contamination area, the epidermal thickness and the percutaneous absorption on the absorbed skin dose rate conversion factors for a set of 39 medical radionuclides. The results show that the absorbed dose to the basal layer of the epidermis can differ by up to two orders of magnitude from the operational quantity H p (0.07) when using an appropriate epidermal thickness in combination with the effect of percutaneous absorption. (paper)

  15. Dose conversion factors for radiation doses at normal operation discharges. E. Exposure pathways and radioecological data; Dosomraekningsfaktorer foer normaldriftutslaepp. C. Exponeringsvaegar och radioekologiska data

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Sara; Aquilonius, Karin

    2001-10-01

    A study has been performed in order to develop and extend existing models for dose estimations at emissions of radioactive substances from nuclear facilities in Sweden. This report presents a review of all exposure pathways in the project, in order to secure that no important contributions have been omitted. The radioecological data that should be used in calculating conversion factors for air and water emissions are also reviewed. Nuclid-specific conversion factors have been calculated for radiation doses from inhalation and intake for children in different age groups.

  16. A simple method for estimating the effective dose in dental CT. Conversion factors and calculation for a clinical low-dose protocol

    International Nuclear Information System (INIS)

    Homolka, P.; Kudler, H.; Nowotny, R.; Gahleitner, A.; Wien Univ.

    2001-01-01

    An easily appliable method to estimate effective dose including in its definition the high radio-sensitivity of the salivary glands from dental computed tomography is presented. Effective doses were calculated for a markedly dose reduced dental CT protocol as well as for standard settings. Data are compared with effective doses from the literature obtained with other modalities frequently used in dental care. Methods: Conversion factors based on the weighted Computed Tomography Dose Index were derived from published data to calculate effective dose values for various CT exposure settings. Results: Conversion factors determined can be used for clinically used kVp settings and prefiltrations. With reduced tube current an effective dose for a CT examination of the maxilla of 22 μSv can be achieved, which compares to values typically obtained with panoramic radiography (26 μSv). A CT scan of the mandible, respectively, gives 123 μSv comparable to a full mouth survey with intraoral films (150 μSv). Conclusion: For standard CT scan protocols of the mandible, effective doses exceed 600 μSv. Hence, low dose protocols for dental CT should be considered whenever feasable, especially for paediatric patients. If hard tissue diagnoses is performed, the potential of dose reduction is significant despite the higher image noise levels as readability is still adequate. (orig.) [de

  17. Uncertainty of the thyroid dose conversion factor for inhalation intakes of 131I and its parametric uncertainty

    International Nuclear Information System (INIS)

    Harvey, R. P.; Hamby, D. M.; Palmer, T. S.

    2006-01-01

    Inhalation exposures of 131 I may occur in the physical form of a gas as well as a particulate. The physical characteristics pertaining to these different types of releases influence the intake and subsequent dose to an exposed individual. The thyroid dose received is influenced by the route through which 131 I enters the body and its subsequent clearance, absorption and movement throughout the body. The radioactive iodine taken up in the gas-exchange tissues is cleared to other tissues or absorbed into the bloodstream of the individual and transferred to other organs. Iodine in the circulatory system is then taken up by the thyroid gland with resulting dose to that tissue. The magnitude of and uncertainty in the thyroid dose is important to the assessment of individuals exposed to airborne releases of radioiodine. Age- and gender-specific modelling parameters have resulted in significant differences between gas uptake, particulate deposition and inhalation dose conversion factors for each age and gender group. Inhalation dose conversion factors and their inherent uncertainty are markedly affected by the type of iodine intake. These differences are expected due to the modelling of particulate deposition versus uptake of gas in the respiratory tract. Inhalation dose estimates via iodine gases are very similar and separate classifications may not be necessarily based on this assessment. (authors)

  18. On the use of quality factors and fluence to dose rate conversion in human radiation exposures

    Science.gov (United States)

    Sondhaus, C. A.

    1972-01-01

    It is shown that various combinations of numbers and factors arrive at estimates of dose and dose effectiveness from values of fluence; but as yet it has not been possible to use biological data with the same degree of precision to estimate the physical data. It would seem that the most reasonable way to use the human data that exist is to apply them as far as possible to the human animal as a whole.

  19. Measurement of conversion coefficients between air Kerma and personal dose equivalent and backscatter factors for diagnostic X-ray beams

    International Nuclear Information System (INIS)

    Rosado, Paulo Henrique Goncalves

    2008-01-01

    Two sets of quantities are import in radiological protection: the protection and operational quantities. Both sets can be related to basic physical quantities such as kerma through conversion coefficients. For diagnostic x-ray beams the conversion coefficients and backscatter factors have not been determined yet, those parameters are need for calibrating dosimeters that will be used to determine the personal dose equivalent or the entrance skin dose. Conversion coefficients between air kerma and personal dose equivalent and backscatter factors were experimentally determined for the diagnostic x-ray qualities RQR and RQA recommended by the International Electrotechnical Commission (IEC). The air kerma in the phantom and the mean energy of the spectrum were measured for such purpose. Harshaw LiF-100H thermoluminescent dosemeters (TLD) were used for measurements after being calibrated against an 180 cm 3 Radcal Corporation ionization chamber traceable to a reference laboratory. A 300 mm x 300 mm x 150 mm polymethylmethacrylate (PMMA) slab phantom was used for deep-dose measurements. Tl dosemeters were placed in the central axis of the x-ray beam at 5, 10, 15, 25 and 35 mm depth in the phantom upstream the beam direction Another required parameter for determining the conversion coefficients from was the mean energy of the x-ray spectrum. The spectroscopy of x-ray beams was done with a CdTe semiconductor detector that was calibrated with 133 Ba, 241 Am and 57 Co radiation sources. Measurements of the x-ray spectra were carried out for all RQR and RQA IEC qualities. Corrections due to the detector intrinsic efficiency, total energy absorption, escape fraction of the characteristic x-rays, Compton effect and attenuation in the detector were done aiming an the accurate determination of the mean energy. Measured x-ray spectra were corrected with the stripping method by using these response functions. The typical combined standard uncertainties of conversion coefficients and

  20. Dose conversion factors for radiation doses at normal operation discharges. F. Methods report; Dosomraekningsfaktorer foer normaldriftutslaepp. F. Metodrapport

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, Ulla; Hallberg, Bengt; Karlsson, Sara

    2001-10-01

    A study has been performed in order to develop and extend existing models for dose estimations at emissions of radioactive substances from nuclear facilities in Sweden. This report gives a review of the different exposure pathways that have been considered in the study. Radioecological data that should be used in calculations of radiation doses are based on the actual situation at the nuclear sites. Dose factors for children have been split in different age groups. The exposure pathways have been carefully re-examined, like the radioecological data; leading to some new pathways (e.g. doses from consumption of forest berries, mushrooms and game) for cesium and strontium. Carbon 14 was given a special treatment by using a model for uptake of carbon by growing plants. For exposure from aquatic emissions, a simplification was done by focussing on the territory for fish species, since consumption of fish is the most important pathway.

  1. Calculation of conversion factor of Kerma in the air for ambient dose equivalent in radiotherapy

    International Nuclear Information System (INIS)

    Lima, Marco Antonio Frota

    2000-03-01

    This work aims to estimate the average conversion factor of Kerma in air to H * (10) using photon beams coming from clinic linear accelerators, transmitted through concrete walls of a radiotherapic treatment room. The transmitted photon spectra by both 1 meter and 2 meters concrete walls, in an area of 40 x 40 cm 2 , were calculated when the primary beam impart in an angle of 0 deg. The (secondary) photon beams transmitted respectively by 0,5 meter, 1,0 meter, 1,0 meter and 2,0 meter concrete walls, after they scattered by an angle of 90 deg in a cylindric phantom inside the room, were also determined. Generally, 50 millions of histories were computed for each simulation made for the primary beam. For the 90 deg spread, the number of histories was 100 millions. The computational code used on this work was the MCNP4B. The most common clinic accelerators used on radiotheraphic treatments were used on this work CLINAC-4, CLINAC-6, CLINAC-18 and CLINAC-2500. From the spectra analysis obtained in this work, it was possible to dispose the conversion factor for realistic beams found in radiotherapeutic establishment. (author)

  2. Dose conversion factors and linear energy transfer for irradiation of thin blood layers with low-energy X rays

    International Nuclear Information System (INIS)

    Verhaegen, F.; Seuntjens, J.

    1994-01-01

    For irradiation of thin samples of biological material with low-energy X rays, conversion of measured air kerma, free in air to average absorbed dose to the sample is necessary. In the present paper, conversion factors from measured air kerma to average absorbed dose in thin blood samples are given for four low-energy X-ray qualities (14-50 kVp). These factors were obtained by Monte Carlo simulation of a practical sample holder. Data for different thicknesses of the blood and backing layer are presented. The conversion factors are found to depend strongly on the thicknesses of the blood layer and backing layer. In radiobiological work, knowledge of linear energy transfer (LET) values for the radiation quality used is often required. Track-averaged LET values for low-energy X rays are presented in this work. It is concluded that the thickness of the sample does not influence the LET value appreciably, indicating that for all radiobiological purposes this value can be regarded as a constant throughout the sample. Furthermore, the large difference between the LET value for a 50 kV spectrum found in this work and the value given in ICRU Report 16 is pointed out. 16 refs., 7 figs., 1 tab

  3. Dose-rate conversion factors for external exposure to photon and electron radiation from radionuclides occurring in routine releases from nuclear fuel cycle facilities

    International Nuclear Information System (INIS)

    Kocher, D.C.

    1980-01-01

    Dose-rate conversion factors for external exposure to photon and electron radiation are calculated for 240 radionuclides of potential importance in routine releases from nuclear fuel cycle facilities. Exposure modes considered are immersion in contaminated air, immersion in contaminated water, and irradiation from a contaminated ground surface. For each exposure mode, dose-rate conversion factors for photons and electrons are calculated for tissue-equivalent material at the body surface of an exposed individual. Dose-rate conversion factors for photons only are calculated for 22 body organs. (author)

  4. Dose-to-risk conversion factors for low-level tritium exposures

    International Nuclear Information System (INIS)

    Straume, T.

    1992-01-01

    During the past decade, a large number of radiobiological studies have become available for tritium-many of them focusing on the relative biological effectiveness (RBE) of tritium beta rays. These and previous studies indicate that tritium in body water produces the same spectrum of radiogenic effects, e.g., cancer, genetic effects, developmental abnormalities, and reproductive effects, observed following whole-body exposure to penetrating radiations such as gamma rays and x rays. The only significant difference in biological response between tritium beta-rays and the other common low linear-energy transfer (LET) radiations, such as gamma rays and x rays, appears to be the greater biological effectiveness of tritium beta rays. For example, tritium in the oxide form (HTO) is about 2 to 3 times more effective at low doses or low dose rates than gamma rays from 137 Cs or 60 CO (Straume, 1991). When tritium is bound to organic molecules, RBE values may be somewhat larger than those for HTO. It is now clear from the wealth of tritium data available that RBEs for tritium beta rays are higher than the quality factor of unity generally used in radiation protection

  5. Models of radionuclide distribution in the biosphere for radioactive waste storage safety assessment, collection of data and calculation of the biosphere dose conversion factors. Research report

    International Nuclear Information System (INIS)

    Landa, Jiri

    2008-12-01

    The core of the report is structured as follows: The biosphere dose conversion factor (BDCF); Foreign approaches (Sweden - SKB, USA - YMP, BIOPROTA); Definition and conversion factors for activity; Effective dose rate calculation (ingestion, inhalation, external irradiation); Analysis of the activity of the surface compartment, i.e. soil; Basic conceptual models of ecosystems; BDCF calculation/determination; and Systemization of the literature. (P.A.)

  6. Evaluation of the use of ICRP 60 dose conversion factors in a postclosure assessment of a deep geological disposal system

    International Nuclear Information System (INIS)

    Palattao, M.V.B.; Hajas, W.C.; Goodwin, B.W.

    1997-05-01

    An Environmental Impact Statement (EIS) of the concept for disposal of Canada's nuclear fuel waste was completed in 1994 and is currently under review by an independent Review Panel. This EIS included a postclosure assessment case study to estimate the annual effective dose equivalent in sieverts per year to members of the public; these estimates were obtained using dose conversion factors (DCFS) based on the 1977 recommendations of the International Commission on Radiation Protection (ICRP). However, in 1990 the ICRP revised these recommendations based on additional biological information and developments in radiation protection. This report describes a study of how the more recent recommendations of the ICRP would affect the results of the postclosure assessment case study presented in the EIS. The report includes a theoretical description of how DCFs are used and a comparison of results from computer simulations using the 1977 and the 1990 ICRP recommendations. In the EIS case study, which was based on the 1977 ICRP recommendations, the total dose rate to a member of the critical group is more than six orders of magnitude below the dose rate associated with the regulatory criterion for individual radiological risk. The total dose rate to 10 4 years is dominated by 129 I, with smaller contributions from 36 C1 and 14 C. If the 1990 ICRP recommendations were implemented, the total dose rate would be mostly affected by the new DCF for 129 I, and would increase by about 67%. Even with this increase, the total dose rate would still remain many orders of magnitude lower than the dose rate associated with the regulatory risk criterion. (author)

  7. Changes of indoor aerosol characteristics and their associated variation on the dose conversion factor due to radon progeny inhalation

    International Nuclear Information System (INIS)

    Tokonami, Shinji; Ishikawa, Tetsuo; Yonehara, Hidenori; Yamada, Yuji; Matsuzawa, Takao; Iimoto, Takeshi

    2003-01-01

    Since the dose conversion factor (hereafter called DCF) due to radon progeny inhalation is strongly dominated by aerosol characteristics in the environment, it is important to understand the air quality for accurate dose assessment. Thus temporal variations on aerosol concentration, its particle size and its related airborne radioactivities were continuously measured in an actual indoor environment with a relatively high radon concentration. The following human activities were added during the observation period: air-conditioning, removal of aerosol with an air cleaner and ventilation. DCFs based on these activities were evaluated with the latest International Commission of Radiological Protection (ICRP) respiratory tract model and were compared among them. Consequently, the present study has shown that operation of air cleaner enhanced the DCF critically because the unattached fraction increased significantly due to removal of aerosols. (author)

  8. Renewal and maintenance of a nuclear structure data file used for the calculations of dose conversion factors

    International Nuclear Information System (INIS)

    Togawa, Orihiko; Yamaguchi, Yukichi

    1996-02-01

    The ENSDF decay data are used as fundamental data to compute radiation data in the DOSDAC code system, which was developed at JAERI, for the calculation of dose conversion factors. The ENSDF decay data have been periodically revised by reviewing new experimental data in the literature under an international network. The use of this data file enables us to calculate radiation data from information which is the newest and internationally recognized. In spite of this advantage, the decay data file is seldom used in applied fields. This is due to some problems to be solved from a viewpoint of the calculation of radiation data, as well as its complicated structure. This report describes methods for renewal and maintenance of the ENSDF decay data used for the calculation of dose conversion factors. In case that the decay data are used directly, attention should be sometimes paid to some problems, for example defects in data. In renewing and using the ENSDF decay data, the DOSDAC code system tries to avoid wrong calculations of radiation data by check and modification of defects in data through four supporting computer codes. (author)

  9. Preliminary results of the average glandular dose to the breast with TLDS measure is computed as the conversion factors

    International Nuclear Information System (INIS)

    Sardo, Luiz T.L.; Almeida, Claudio D.; Coutinho, Celia M.C.

    2013-01-01

    At mammography exams there is a risk of a breast cancer induced from the absorbed dose by the glandular tissue. According to the National Institute of Cancer, INCA, breast cancer is the second type most frequent in the world and the most common among women, therefore the necessity of monitoring the mean glandular dose, D G . Measuring methods of D G were established by some authors. Among the established methods the method of Dance is one of the most known. In this study was utilized a measurement method realized with TL dosimeters inserted in a breast tissue equivalent phantom, BTE, with 46% of glandularity and exposed using Mo/Mo and Mo/Rh target/filter combination and 28kV. To ensure this measurement method the results were compared with a calculation method, used by Dance, of D G from the measurement of incident air kerma, K i , and conversion factors to consider mainly the beam quality, the compressed thickness and the glandularity of the breast. The results of the comparison of the D G measurement with the obtained dose by the method of Dance demonstrated that for the thickness of 4.0 and 6.0 cm the doses were consistent. For the thickness of 5.0 cm the difference was higher, indicating that the glandularity may influence, suggesting further investigation. (author)

  10. Software Development for Estimating the Conversion Factor (K-Factor) at Suitable Scan Areas, Relating the Dose Length Product to the Effective Dose.

    Science.gov (United States)

    Kobayashi, Masanao; Asada, Yasuki; Matsubara, Kosuke; Suzuki, Syouichi; Koshida, Kichiro; Matsunaga, Yuta; Kawaguchi, Ai; Haba, Tomonobu; Toyama, Hiroshi; Kato, Ryouichi

    2017-05-01

    We developed a k-factor-creator software (kFC) that provides the k-factor for CT examination in an arbitrary scan area. It provides the k-factor from the effective dose and dose-length product by Imaging Performance Assessment of CT scanners and CT-EXPO. To assess the reliability, we compared the kFC-evaluated k-factors with those of the International Commission on Radiological Protection (ICRP) publication 102. To confirm the utility, the effective dose determined by coronary computed tomographic angiography (CCTA) was evaluated by a phantom study and k-factor studies. In the CCTA, the effective doses were 5.28 mSv in the phantom study, 2.57 mSv (51%) in the k-factor of ICRP, and 5.26 mSv (1%) in the k-factor of the kFC. Effective doses can be determined from the kFC-evaluated k-factors in suitable scan areas. Therefore, we speculate that the flexible k-factor is useful in clinical practice, because CT examinations are performed in various scan regions. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Software development for estimating the conversion factor (k-factor) at suitable scan areas, relating the dose length product to the effective dose

    International Nuclear Information System (INIS)

    Kobayashi, Masanao; Asada, Yasuki; Suzuki, Syouichi; Kato, Ryouichi; Matsubara, Kosuke; Koshida, Kichiro; Matsunaga, Yuta; Kawaguchi, Ai; Haba, Tomonobu; Toyama, Hiroshi

    2017-01-01

    We developed a k-factor-creator software (kFC) that provides the k-factor for CT examination in an arbitrary scan area. It provides the k-factor from the effective dose and dose-length product by Imaging Performance Assessment of CT scanners and CT-EXPO. To assess the reliability, we compared the kFC-evaluated k-factors with those of the International Commission on Radiological Protection (ICRP) publication 102. To confirm the utility, the effective dose determined by coronary computed tomographic angiography (CCTA) was evaluated by a phantom study and k-factor studies. In the CCTA, the effective doses were 5.28 mSv in the phantom study, 2.57 mSv (51%) in the k-factor of ICRP, and 5.26 mSv (1%) in the k-factor of the kFC. Effective doses can be determined from the kFC-evaluated k-factors in suitable scan areas. Therefore, we speculate that the flexible k-factor is useful in clinical practice, because CT examinations are performed in various scan regions. (authors)

  12. ZZ DOSDAT-2, Gamma and Electron Dose Conversion Factor Data Library for Body Organs

    International Nuclear Information System (INIS)

    1983-01-01

    1 - Description of problem or function: Format: DOSDAT-R; Nuclides: gamma-ray and electron dose rates for whole-body and for various body organs (24) for air and water immersion and from ground-surface sources (approximately 500 radioactive nuclides). Origin: DLC-80/DRALIST library of radioactive decay data. The data are used to estimate the gamma-ray and electron dose rates for whole-body and for various body organs (24) for air and water immersion and from ground-surface sources. The data are given for approximately 500 radioactive nuclides. 2 - Method of solution: The data were computed by the CCC-400 DOSAFACTER II code from the DLC-80/DRALIST library of radioactive decay data for approximately 500 nuclides

  13. Conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation, 1945--1947. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Mart, E.I.; Denham, D.H.; Thiede, M.E.

    1993-12-01

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the U.S. Department of Energy`s (DOE) Hanford Site near Richland, Washington. The HEDR Project is conducted by Battelle, Pacific Northwest Laboratories (BNW). One of the radionuclides emitted that would affect the radiation dose was iodine-131. This report describes in detail the reconstructed conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation which was collected from the beginning of October 1945 through the end of December 1947.

  14. External dose-rate conversion factors of radionuclides for air submersion, ground surface contamination and water immersion based on the new ICRP dosimetric setting.

    Science.gov (United States)

    Yoo, Song Jae; Jang, Han-Ki; Lee, Jai-Ki; Noh, Siwan; Cho, Gyuseong

    2013-01-01

    For the assessment of external doses due to contaminated environment, the dose-rate conversion factors (DCFs) prescribed in Federal Guidance Report 12 (FGR 12) and FGR 13 have been widely used. Recently, there were significant changes in dosimetric models and parameters, which include the use of the Reference Male and Female Phantoms and the revised tissue weighting factors, as well as the updated decay data of radionuclides. In this study, the DCFs for effective and equivalent doses were calculated for three exposure settings: skyshine, groundshine and water immersion. Doses to the Reference Phantoms were calculated by Monte Carlo simulations with the MCNPX 2.7.0 radiation transport code for 26 mono-energy photons between 0.01 and 10 MeV. The transport calculations were performed for the source volume within the cut-off distances practically contributing to the dose rates, which were determined by a simplified calculation model. For small tissues for which the reduction of variances are difficult, the equivalent dose ratios to a larger tissue (with lower statistical errors) nearby were employed to make the calculation efficient. Empirical response functions relating photon energies, and the organ equivalent doses or the effective doses were then derived by the use of cubic-spline fitting of the resulting doses for 26 energy points. The DCFs for all radionuclides considered important were evaluated by combining the photon emission data of the radionuclide and the empirical response functions. Finally, contributions of accompanied beta particles to the skin equivalent doses and the effective doses were calculated separately and added to the DCFs. For radionuclides considered in this study, the new DCFs for the three exposure settings were within ±10 % when compared with DCFs in FGR 13.

  15. The conversion factor of α radiation efficiency

    International Nuclear Information System (INIS)

    Wang Weida; Zhou Zhixin; Xia Junding

    1997-01-01

    It is important in fine-grain TL dating that the full α dose must be converted into the equivalent β dose. Although the conversion coefficient K for internal radiation efficiency can not be measured directly for each sample, it is possible to measure the external radiation efficiency K 3.7 . For this purpose a special study for the conversion factor of K to K 3.7 has been made using ultrathin TLD. The results show that the conversion factor of the TLD for archaeological samples is 0.847, which is in agreement with the calculated value 0.85

  16. Alkaline earth metabolism: a model useful in calculating organ burdens, excretion rates and committed effective dose equivalent conversion factors

    International Nuclear Information System (INIS)

    Johnson, J.R.; Myers, R.C.

    1981-01-01

    Two mathematical models of alkaline earth metabolism in man have been developed from the postulates given in ICRP Publication 20. Both models have recycling between the organs and blood included explicitly, and the first one retains the power function used by the ICRP for diminution in mineral bone from being available for resorption by blood. In the second model, this diminution is represented by secondary compartments in mineral bone. Both models give good agreement with the retention functions developed in ICRP Publication 20. The second one has been incorporated into a larger model which includes the lung and G.I. tract. This overall model has been used to calculate organ burdens excretion rates, and committed effective dose equivalent factors for the more important radioisotopes of the alkaline earth elements for inhalation and ingestion exposures. (author)

  17. Determination of conversion factors of kerma and fluence to ambient dose equivalent for X-rays generated between 50 kVp to 125 kVp

    International Nuclear Information System (INIS)

    Nogueira, Maria do Socorro

    1997-01-01

    The ambient dose equivalent was determined experimentally on the interval of energy of X ray applied in diagnostic radiology. A PMMA sphere was used to simulate the trunk human (phantom), based on the definition of the report ICRU 39. The absorbed dose in different positions in the phantom was determined using LiF-TLD 100. The X ray spectra were measured with a high-purity germanium detector (HP Ge). It was also determined the HVL and the effective energy in this energy range. The conversion coefficient of the K air and Φ to H * (d) were determined to 10, 50 and 60 mm deep in the PMMA sphere. The obtained values were compared with data of the literature. The maximum uncertainty obtained for the coefficients was 7.2%. All parameters were also determined to the X ray quality of the incident and transmitted beam by the patient, according to the recommendation of the standard DIN 6872. The conversion factor was calculated for those situations where the X-ray beam is transmitted by a layer and Pb and it is necessary to estimate the effective dose, as in the case of shielding project of radiology diagnosis room. (author)

  18. Modeling the Long-term Transport and Accumulation of Radionuclides in the Landscape for Derivation of Dose Conversion Factors

    International Nuclear Information System (INIS)

    Avila, Rodolfo Moreno; Ekstroem, Per-Anders; Kautsky, Ulrik

    2006-01-01

    To evaluate the radiological impact of potential releases to the biosphere from a geological repository for spent nuclear fuel, it is necessary to assess the long-term dynamics of the distribution of radionuclides in the environment. In this paper, we propose an approach for making prognoses of the distribution and fluxes of radionuclides released from the geosphere, in discharges of contaminated groundwater, to an evolving landscape. The biosphere changes during the temperate part (spanning approximately 20,000 years) of an interglacial period are handled by building biosphere models for the projected succession of situations. Radionuclide transport in the landscape is modeled dynamically with a series of interconnected radioecological models of those ecosystem types (sea, lake, running water, mire, agricultural land and forest) that occur at present, and are projected to occur in the future, in a candidate area for a geological repository in Sweden. The transformation between ecosystems is modeled as discrete events occurring every thousand years by substituting one model by another. Examples of predictions of the radionuclide distribution in the landscape are presented for several scenarios with discharge locations varying in time and space. The article also outlines an approach for estimating the exposure of man resulting from all possible reasonable uses of a potentially contaminated landscape, which was used for derivation of Landscape Dose Factors

  19. Dose conversion factor for radon concentration in indoor environments using a new equation for the F-fp correlation

    International Nuclear Information System (INIS)

    Vargas, A.; Ortega, X.; Porta, M.

    2000-01-01

    Since 1994 the radon studies group at the Institut de Techniques Energetiques (INTE) of the Universitat Politecnica de Catalunya in Barcelona, Spain, has carried out a campaign of continuous measurements of the equilibrium factor (F) and the unattached fraction (f p ) of radon decay products at four sites which are representative of different environmental characteristics on the Mediterranean littoral of Catalonia, Spain. It has been established that these parameters vary widely, F(0.03--0.87) and f p (0--0.72), from one site to another and with time, according to the characteristics on the site and climate. In spite of this variation, the F and f p parameters are log-normally or normally distributed. The measurements of F and f p show that f p is negatively correlated to F by a log-power equation, Ln(1/f p )=1.90[Ln(1/F)] -0.68 , which can be used in all the F range, instead of the commonly used power equation f p =aF b suggested by Stranden and Strand and other authors, which fits well for a reduced range of F. Power and log-power equations have been introduced into a simplified dosimetric model in order to estimate the effective dose per unit radon exposure as a function of F. From the log-power equation this value is quite constant and ranged from 9 nSv per B1 m -3 h to 12 nSv per B1 m -3 h when F is higher than 0.15. In the case of a lower F factor, a linear function that passes through 0 fits quite well. A value of 12 nSv per B1 m -3 h is proposed for the Mediterranean littoral of Catalonia as the best estimation

  20. Limiting values of radionuclide intake and air concentration and dose conversion factors for inhalation, submersion, and ingestion: Federal guidance report No. 11

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Wolbarst, A.B.; Richardson, A.C.B.

    1988-09-01

    Radiation protection programs for workers are based, in the United States, on a hierarchy of limitations stemming from Federal guidance approved by the President. This guidance, which consists of principles, policies, and numerical primary guides, is used by Federal agencies as the basis for developing and implementing their own regulatory standards. The primary guides are usually expressed in terms of limiting doses to workers. The protection of workers against taking radioactive materials into the body, however, is accomplished largely through the use of regulations based on derived guides expressed in terms of quantities or concentrations of radionuclides. The values of these derived guides are chosen so as to assure that workers in work environments that conform to them are unlikely to receive radiation doses that exceed the primary guides. The purpose of the present report is to set forth derived guides that are consistent with current Federal radiation protection guidance. They are intended to serve as the basis for regulations setting upper bounds on the inhalation and ingestion of, and submersion in, radioactive materials in the workplace. The report also includes tables of exposure-to-dose conversion factors, for general use in assessing average individual committed doses in any population that is adequately characterized by Reference Man. 38 refs

  1. Limiting values of radionuclide intake and air concentration and dose conversion factors for inhalation, submersion, and ingestion: Federal guidance report No. 11

    Energy Technology Data Exchange (ETDEWEB)

    Eckerman, K.F.; Wolbarst, A.B.; Richardson, A.C.B.

    1988-09-01

    Radiation protection programs for workers are based, in the United States, on a hierarchy of limitations stemming from Federal guidance approved by the President. This guidance, which consists of principles, policies, and numerical primary guides, is used by Federal agencies as the basis for developing and implementing their own regulatory standards. The primary guides are usually expressed in terms of limiting doses to workers. The protection of workers against taking radioactive materials into the body, however, is accomplished largely through the use of regulations based on derived guides expressed in terms of quantities or concentrations of radionuclides. The values of these derived guides are chosen so as to assure that workers in work environments that conform to them are unlikely to receive radiation doses that exceed the primary guides. The purpose of the present report is to set forth derived guides that are consistent with current Federal radiation protection guidance. They are intended to serve as the basis for regulations setting upper bounds on the inhalation and ingestion of, and submersion in, radioactive materials in the workplace. The report also includes tables of exposure-to-dose conversion factors, for general use in assessing average individual committed doses in any population that is adequately characterized by Reference Man. 38 refs.

  2. Quantitative relations between beta-gamma mixed-field dosimeter responses and dose-equivalent conversion factors according to the testing standard

    International Nuclear Information System (INIS)

    Gupta, V.P.

    1982-08-01

    The conventional two-element personnel dosimeters, usually having two thick TLD (thermoluminescent dosimetry) ribbons, are used extensively for radiation protection dosimetry. Many of these dosimeters are used for the measurement of beta and gamma radiation doses received in mixed beta-gamma fields. Severe limitations exist, however, on the relative magnitudes and energies of these fields that may be measured simultaneously. Moreover, due to a well-known energy dependence of these dosimeters, particularly for the beta-radiations, systematic errors will occur whenever the differences in workplaces and calibration radiation energies exist. A simple mathematical approach is presented to estimate the deep and shallow dose equivalent values at different energies for such dosimeters. The formulae correlate the dosimeter responses and dose equivalent conversion factors at different energies by taking into account the guidelines of the adopted ANSI Standard N13.11 and the dosimetry practices followed by most dosimeter processors. This standard is to be used in a mandatory testing program in the United States

  3. Conversion factors and oil statistics

    International Nuclear Information System (INIS)

    Karbuz, Sohbet

    2004-01-01

    World oil statistics, in scope and accuracy, are often far from perfect. They can easily lead to misguided conclusions regarding the state of market fundamentals. Without proper attention directed at statistic caveats, the ensuing interpretation of oil market data opens the door to unnecessary volatility, and can distort perception of market fundamentals. Among the numerous caveats associated with the compilation of oil statistics, conversion factors, used to produce aggregated data, play a significant role. Interestingly enough, little attention is paid to conversion factors, i.e. to the relation between different units of measurement for oil. Additionally, the underlying information regarding the choice of a specific factor when trying to produce measurements of aggregated data remains scant. The aim of this paper is to shed some light on the impact of conversion factors for two commonly encountered issues, mass to volume equivalencies (barrels to tonnes) and for broad energy measures encountered in world oil statistics. This paper will seek to demonstrate how inappropriate and misused conversion factors can yield wildly varying results and ultimately distort oil statistics. Examples will show that while discrepancies in commonly used conversion factors may seem trivial, their impact on the assessment of a world oil balance is far from negligible. A unified and harmonised convention for conversion factors is necessary to achieve accurate comparisons and aggregate oil statistics for the benefit of both end-users and policy makers

  4. Overview of the unified program of the scaling factor determination program and the dose to curie conversion program

    International Nuclear Information System (INIS)

    Lee, Sang Chul; Hwang, Ki Ha; Lee, Kun Jai; Kim, Tae Wook; Kim, Kyoung Doek; Song, Myung Jae

    2005-01-01

    Final disposal of radioactive waste generated from Nuclear Power Plant (NPP) requires the information of the radionuclides inventories in waste package by national regulations and guidelines. However, the direct assessment through the destruction of the drummed radioactive waste for all stored drums is difficult economically and time-consuming. KAIST developed the program for the SF determination method based on the database for the activity of the each selected nuclide analyzed by KAERI using the statistical method such as log mean average (LMA) generally and the theoretical method for some fission nuclides. To improve the reliability of the SF calculated by the program, two methods have been applied. The first method is the calculation of scaling factor by grouping the waste type or plant type of the database set. The other method is the calculation of SF after the outlier of the database is eliminated

  5. Preliminary results of the average glandular dose to the breast with TLDS measure is computed as the conversion factors; Resultados preliminares da dose glandular media na mama medida com TLDS e calculada atraves de fatores de conversao

    Energy Technology Data Exchange (ETDEWEB)

    Sardo, Luiz T.L.; Almeida, Claudio D.; Coutinho, Celia M.C., E-mail: ltsardo@yahoo.com.br, E-mail: claudio@ird.gov.br, E-mail: celia@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    At mammography exams there is a risk of a breast cancer induced from the absorbed dose by the glandular tissue. According to the National Institute of Cancer, INCA, breast cancer is the second type most frequent in the world and the most common among women, therefore the necessity of monitoring the mean glandular dose, D{sub G}. Measuring methods of D{sub G} were established by some authors. Among the established methods the method of Dance is one of the most known. In this study was utilized a measurement method realized with TL dosimeters inserted in a breast tissue equivalent phantom, BTE, with 46% of glandularity and exposed using Mo/Mo and Mo/Rh target/filter combination and 28kV. To ensure this measurement method the results were compared with a calculation method, used by Dance, of D{sub G} from the measurement of incident air kerma, K{sub i}, and conversion factors to consider mainly the beam quality, the compressed thickness and the glandularity of the breast. The results of the comparison of the D{sub G} measurement with the obtained dose by the method of Dance demonstrated that for the thickness of 4.0 and 6.0 cm the doses were consistent. For the thickness of 5.0 cm the difference was higher, indicating that the glandularity may influence, suggesting further investigation. (author)

  6. Dose conversion factors of radiation doses at normal operation discharges. E. Description of geographical surroundings and critical group; Dosomraekningsfaktorer foer normaldriftutslaepp. E. Omraadesbeskrivningar och kritisk grupp

    Energy Technology Data Exchange (ETDEWEB)

    Hallberg, Bengt

    2001-10-01

    A study was performed in order to develop and supplement existing models for calculating radiation doses from discharges of radionuclides under normal operating conditions at the Swedish NPPs at Barsebaeck, Forsmark, Oskarshamn and Ringhals, and at the nuclear plants at Studsvik and the Westinghouse Atom fuel plant. A general description of the surroundings of each plant is given in this report, together with an inventory of agricultural activities, forestry, areas for leisure activities etc. The conditions of the critical group has been selected based on the description of the surroundings and the modeling of dispersion in the atmosphere and fallout on the ground. In contrast to earlier models where fictive critical groups were used, the present model is based on factual circumstances.

  7. A dose to curie conversion methodology

    International Nuclear Information System (INIS)

    Stowe, P.A.

    1987-01-01

    Development of the computer code RadCAT (Radioactive waste Classification And Tracking) has led to the development of a simple dose rate to curie content conversion methodology for containers with internally distributed radioactive material. It was determined early on that, if possible, the computerized dose rate to curie evaluation model employed in RadCAT should yield the same results as the hand method utilized and specified in plant procedures. A review of current industry practices indicated two distinct types of computational methodologies are presently in use. The most common methods are computer based calculations utilizing complex mathematical models specifically established for various containers geometries. This type of evaluation is tedious, however, and does not lend itself to repetition by hand. The second method of evaluation, therefore, is simplified expressions that sacrifice accuracy for ease of computation, and generally over estimate container curie content. To meet the aforementioned criterion current computer based models were deemed unacceptably complex and hand computational methods to be too inaccurate for serious consideration. The contact dose rate/curie content analysis methodology presented herein provides an equation that is easy to use in hand calculations yet provides accuracy equivalent to other computer based computations

  8. On the conversion of dose to bone to dose to water in radiotherapy treatment planning systems

    Directory of Open Access Journals (Sweden)

    Nick Reynaert

    2018-01-01

    Full Text Available Background and purpose: Conversion factors between dose to medium (Dm,m and dose to water (Dw,w provided by treatment planning systems that model the patient as water with variable electron density are currently based on stopping power ratios. In the current paper it will be illustrated that this conversion method is not correct. Materials and methods: Monte Carlo calculations were performed in a phantom consisting of a 2 cm bone layer surrounded by water. Dw,w was obtained by modelling the bone layer as water with the electron density of bone. Conversion factors between Dw,w and Dm,m were obtained and compared to stopping power ratios and ratios of mass-energy absorption coefficients in regions of electronic equilibrium and interfaces. Calculations were performed for 6 MV and 20 MV photon beams. Results: In the region of electronic equilibrium the stopping power ratio of water to bone (1.11 largely overestimates the conversion obtained using the Monte Carlo calculations (1.06. In that region the MC dose conversion corresponds to the ratio of mass energy absorption coefficients. Near the water to bone interface, the MC ratio cannot be determined from stopping powers or mass energy absorption coefficients. Conclusion: Stopping power ratios cannot be used for conversion from Dm,m to Dw,w provided by treatment planning systems that model the patient as water with variable electron density, either in regions of electronic equilibrium or near interfaces. In regions of electronic equilibrium mass energy absorption coefficient ratios should be used. Conversions at interfaces require detailed MC calculations. Keywords: Dose to water, Monte Carlo, Dosimetry, TPS comparison

  9. Dose conversion of radon exposure according to new epidemiological findings

    International Nuclear Information System (INIS)

    Tomasek, L.; Rogel, A.; Laurier, D.; Tirmarche, M.

    2008-01-01

    In 1993, ICRP-65 recommended that dose conversion of radon exposure should be based on the comparison of detriments between radon exposure and effective dose. The lifetime detriment from the radon exposure was projected according to the epidemiological studies of uranium miners then available. The projection model (GSF) was multiplicative with temporal and age-at-exposure modification. Since 1993, new studies of uranium miners have appeared and many original studies were updated. In addition, projections of the risk have been improved by including further modifying factors as for instance in BEIR VI. New analyses were completed in the Czech and French studies of uranium miners with accurate estimates of exposures based on extensive radon measurements. The resulting estimates of excess absolute lifetime risk per unit exposure in working level months (WLM) from these models lead to dose conversion of 10 mSv WLM -1 for the BEIR VI model and 8 mSv WLM -1 for the joint Czech-French model in contrast to the conversion of 5 mSv WLM -1 for the GSF model. (authors)

  10. Dose conversion coefficients for high-energy photons, electrons, neutrons and protons

    CERN Document Server

    Sakamoto, Y; Sato, O; Tanaka, S I; Tsuda, S; Yamaguchi, Y; Yoshizawa, N

    2003-01-01

    In the International Commission on Radiological Protection (ICRP) 1990 Recommendations, radiation weighting factors were introduced in the place of quality factors, the tissue weighting factors were revised, and effective doses and equivalent doses of each tissues and organs were defined as the protection quantities. Dose conversion coefficients for photons, electrons and neutrons based on new ICRP recommendations were cited in the ICRP Publication 74, but the energy ranges of theses data were limited and there are no data for high energy radiations produced in accelerator facilities. For the purpose of designing the high intensity proton accelerator facilities at JAERI, the dose evaluation code system of high energy radiations based on the HERMES code was developed and the dose conversion coefficients of effective dose were evaluated for photons, neutrons and protons up to 10 GeV, and electrons up to 100 GeV. The dose conversion coefficients of effective dose equivalent were also evaluated using quality fact...

  11. Dose conversion coefficients for high-energy photons, electrons, neutrons and protons

    International Nuclear Information System (INIS)

    Sakamoto, Yukio

    2005-01-01

    Dose conversion coefficients for photons, electrons and neutrons based on new ICRP recommendations were cited in the ICRP Publication 74, but the energy ranges of these data were limited and there are no data for high energy radiations produced in accelerator facilities. For the purpose of designing the high intensity proton accelerator facilities at JAERI, the dose evaluation code system of high energy radiations based on the HERMES code was developed and the dose conversion coefficients of effective dose were evaluated for photons, neutrons and protons up to 10 GeV, and electrons up to 100 GeV. The dose conversion coefficients of effective dose equivalent were also evaluated using quality factors to consider the consistency between radiation weighting factors and Q-L relationship. The effective dose conversion coefficients obtained in this work were in good agreement with those recently evaluated by using FLUKA code for photons and electrons with all energies, and neutrons and protons below 500 MeV. There were some discrepancy between two data owing to the difference of cross sections in the nuclear reaction models. The dose conversion coefficients of effective dose equivalents for high energy radiations based on Q-L relation in ICRP Publication 60 were evaluated only in this work. The previous comparison between effective dose and effective dose equivalent made it clear that the radiation weighting factors for high energy neutrons and protons were overestimated and the modification was required. (author)

  12. A simple method for conversion of airborne gamma-ray spectra to ground level doses

    DEFF Research Database (Denmark)

    Korsbech, Uffe C C; Bargholz, Kim

    1996-01-01

    A new and simple method for conversion of airborne NaI(Tl) gamma-ray spectra to dose rates at ground level has been developed. By weighting the channel count rates with the channel numbers a spectrum dose index (SDI) is calculated for each spectrum. Ground level dose rates then are determined...... by multiplying the SDI by an altitude dependent conversion factor. The conversion factors are determined from spectra based on Monte Carlo calculations. The results are compared with measurements in a laboratory calibration set-up. IT-NT-27. June 1996. 27 p....

  13. A radiological dose assessment for the Port Hope conversion facility

    International Nuclear Information System (INIS)

    Garisto, N.C.; Cooper, F.; Janes, A.; Stager, R.; Peters, R.

    2011-01-01

    The Port Hope Conversion Facility (PHCF) receives uranium trioxide for conversion to uranium hexafluoride (UF 6 ) or uranium dioxide (UO 2 ). The PHCF Site has a long history of industrial use. A Radiological Dose Assessment was undertaken as part of a Site Wide Risk Assessment. This assessment took into account all possible human receptors, both workers and members of the public. This paper focuses on a radiological assessment of dose to members of the public. The doses to members of the public from terrestrial pathways were added to the doses from aquatic pathways to obtain overall dose to receptors. The benchmark used in the assessment is 1 mSv/y. The estimated doses related to PHCF operations are much lower than the dose limit. (author)

  14. Disruptive Event Biosphere Doser Conversion Factor Analysis

    Energy Technology Data Exchange (ETDEWEB)

    M. Wasiolek

    2000-12-28

    The purpose of this report was to document the process leading to, and the results of, development of radionuclide-, exposure scenario-, and ash thickness-specific Biosphere Dose Conversion Factors (BDCFs) for the postulated postclosure extrusive igneous event (volcanic eruption) at Yucca Mountain. BDCF calculations were done for seventeen radionuclides. The selection of radionuclides included those that may be significant dose contributors during the compliance period of up to 10,000 years, as well as radionuclides of importance for up to 1 million years postclosure. The approach documented in this report takes into account human exposure during three different phases at the time of, and after, volcanic eruption. Calculations of disruptive event BDCFs used the GENII-S computer code in a series of probabilistic realizations to propagate the uncertainties of input parameters into the output. The pathway analysis included consideration of different exposure pathway's contribution to the BDCFs. BDCFs for volcanic eruption, when combined with the concentration of radioactivity deposited by eruption on the soil surface, allow calculation of potential radiation doses to the receptor of interest. Calculation of radioactivity deposition is outside the scope of this report and so is the transport of contaminated ash from the volcano to the location of the receptor. The integration of the biosphere modeling results (BDCFs) with the outcomes of the other component models is accomplished in the Total System Performance Assessment (TSPA), in which doses are calculated to the receptor of interest from radionuclides postulated to be released to the environment from the potential repository at Yucca Mountain.

  15. Conversion coefficients for determining organ doses in paediatric spine radiography

    Energy Technology Data Exchange (ETDEWEB)

    Seidenbusch, Michael; Schneider, Karl [Ludwig-Maximilians-University of Munich, Institute of Clinical Radiology - Paediatric Radiology, Muenchen (Germany)

    2014-04-15

    Knowledge of organ and effective doses achieved during paediatric x-ray examinations is an important prerequisite for assessment of radiation burden to the patient. Conversion coefficients for reconstruction of organ and effective doses from entrance doses for segmental spine radiographs of 0-, 1-, 5-, 10-, 15- and 30-year-old patients are provided regarding the Guidelines of Good Radiographic Technique of the European Commission. Using the personal computer program PCXMC developed by the Finnish Centre for Radiation and Nuclear Safety (Saeteilyturvakeskus STUK), conversion coefficients for conventional segmental spine radiographs were calculated performing Monte Carlo simulations in mathematical hermaphrodite phantom models describing patients of different ages. The clinical variation of beam collimation was taken into consideration by defining optimal and suboptimal radiation field settings. Conversion coefficients for the reconstruction of organ doses in about 40 organs and tissues from measured entrance doses during cervical, thoracic and lumbar spine radiographs of 0-, 1-, 5-, 10-, 15- and 30-year-old patients were calculated for the standard sagittal and lateral beam projections and the standard focus detector distance of 115 cm. The conversion coefficients presented may be used for organ dose assessments from entrance doses measured during spine radiographs of patients of all age groups and all field settings within the optimal and suboptimal standard field settings. (orig.)

  16. Conversion of ionization measurements to radiation absorbed dose in non-water density material

    International Nuclear Information System (INIS)

    El-Khatib, E.; Connors, S.

    1992-01-01

    In bone-equivalent materials two different calculations of absorbed dose are possible: the absorbed dose to soft tissue plastic (polystyrene) within bone-equivalent material and the dose to the bone-equivalent material itself. Both can be calculated from ionization measurements in phantoms. These two calculations result in significantly different doses in a heterogeneous phantom composed of polystyrene and aluminium (a bone substitute). The dose to a thin slab of polystyrene in aluminium is much higher than the dose to the aluminium itself at the same depth in the aluminium. Monte Carlo calculations confirm that the calculation of dose to polystyrene in aluminium can be accurately carried out using existing dosimetry protocols. However, the conversion of ionization measurements to absorbed dose to high atomic number materials cannot be accurately carried out with existing protocols and appropriate conversion factors need to be determined. (author)

  17. Calculation of conversion factor of Kerma in the air for ambient dose equivalent in radiotherapy; Calculo dos fatores de conversao de Kerma no ar para equivalente de dose ambiental em radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Marco Antonio Frota

    2000-03-01

    This work aims to estimate the average conversion factor of Kerma in air to H {sup *} (10) using photon beams coming from clinic linear accelerators, transmitted through concrete walls of a radiotherapic treatment room. The transmitted photon spectra by both 1 meter and 2 meters concrete walls, in an area of 40 x 40 cm{sup 2}, were calculated when the primary beam impart in an angle of 0 deg. The (secondary) photon beams transmitted respectively by 0,5 meter, 1,0 meter, 1,0 meter and 2,0 meter concrete walls, after they scattered by an angle of 90 deg in a cylindric phantom inside the room, were also determined. Generally, 50 millions of histories were computed for each simulation made for the primary beam. For the 90 deg spread, the number of histories was 100 millions. The computational code used on this work was the MCNP4B. The most common clinic accelerators used on radiotheraphic treatments were used on this work CLINAC-4, CLINAC-6, CLINAC-18 and CLINAC-2500. From the spectra analysis obtained in this work, it was possible to dispose the conversion factor for realistic beams found in radiotherapeutic establishment. (author)

  18. Electron fluence to dose equivalent conversion factors calculated with EGS3 for electrons and positrons with energies from 100 keV to 20 GeV

    International Nuclear Information System (INIS)

    Rogers, D.W.O.

    1983-01-01

    At NRC the general purpose Monte-Carlo electron-photon transport code EGS3 is being applied to a variety of radiation dosimetry problems. To test its accuracy at low energies a detailed set of depth-dose curves for electrons and photons has been generated and compared to previous calculations. It was found that by changing the default step-size algorithm in EGS3, significant changes were obtained for incident electron beam cases. It was found that restricting the step-size to a 4% energy loss was appropriate below incident electron beam energies of 10 MeV. With this change, the calculated depth-dose curves were found to be in reasonable agreement with other calculations right down to incident electron energies of 100 keV although small (less than or equal to 10%) but persistent discrepancies with the NBS code ETRAN were obtained. EGS3 predicts higher initial dose and shorter range than ETRAN. These discrepancies are typical of a wide range of energies as is the better agreement with the results of Nahum. Data is presented for the electron fluence to maximal dose equivalent in a 30 cm thick slab of ICRU 4-element tissue irradiated by broad parallel beams of electrons incident normal to the surface. On their own, these values only give an indication of the dose equivalent expected from a spectrum of electrons since one needs to fold the spectrum maximal dose equivalent value. Calculations have also been done for incident positron beams. Despite the large statistical uncertainties, maximal dose equivalent although their values are 5 to 10% lower in a band around 10 MeV

  19. Age-dependent conversion coefficients for organ doses and effective doses for external neutron irradiation

    International Nuclear Information System (INIS)

    Nishizaki, Chihiro; Endo, Akira; Takahashi, Fumiaki

    2006-06-01

    To utilize dose assessment of the public for external neutron irradiation, conversion coefficients of absorbed doses of organs and effective doses were calculated using the numerical simulation technique for six different ages (adult, 15, 10, 5 and 1 years and newborn), which represent the member of the public. Calculations were performed using six age-specific anthropomorphic phantoms and a Monte Carlo radiation transport code for two irradiation geometries, anterior-posterior and rotational geometries, for 20 incident energies from thermal to 20 MeV. Effective doses defined by the 1990 Recommendation of ICRP were calculated from the absorbed doses in 21 organs. The calculated results were tabulated in the form of absorbed doses and effective doses per unit neutron fluence. The calculated conversion coefficients are used for dose assessment of the public around nuclear facilities and accelerator facilities. (author)

  20. Outlines of ICRP publication 74 and new dose conversion coefficients for external radiation

    International Nuclear Information System (INIS)

    Yamaguchi, Yasuhiro

    1998-01-01

    Combined task group of ICRP and ICRU reported the ICRP Publication 74 (1996) which is a summary report of their collection, analysis and evaluation of many data and dose conversion coefficients. Concerning the new coefficients, the author described this review as follows: History until Publication 74. Doses recommended at present: for protection quantity, the mean absorption dose of organ and tissue, equivalent dose and effective dose and for operational quantity, the ambient dose equivalent, directional dose equivalent and individual dose equivalent. Changes which can have an influence on the dose evaluation; introduction of radiation weighting factor (WR), changing of tissue weighting factor (WR), changing of the equation for Q-L relation and updating of physical data. New dose conversion coefficients; for photon, neutron and electron. Comparison of new and present coefficients; concerning the quality factor Q, particularly for neutron Q. New relations of protection and operational quantities; for field and individual monitoring. General conclusion of Publication 74. The Publication gives a certain direction for problems in evaluation of external exposure dose which have been discussed since the ICRP Fundamental Recommendation 1990 was issued. However, there still remain many problems especially in validity of the WR and of equation for Q-L relation. (K.H.)

  1. Photon dose conversion coefficients for the human teeth in standard irradiation geometries

    Energy Technology Data Exchange (ETDEWEB)

    Ulanovsky, A; Wieser, A; Zankl, M; Jacob, P

    2005-07-01

    Photon dose conversion coefficients for the human tooth materials are computed in energy range from 0.01 to 10 MeV by the Monte Carlo method. The voxel phantom Golem of the human body with newly defined tooth region and a modified version of the EGS4 code have been used to compute the coefficients for 30 tooth cells with different locations and materials. The dose responses are calculated for cells representing buccal and lingual enamel layers. The computed coefficients demonstrate a strong dependence on energy and geometry of the radiation source and a weaker dependence on location of the enamel voxels. For isotropic and rotational radiation fields the enamel dose does not show a significant dependence on tooth sample locations. The computed coefficients are used to convert from absorbed dose in teeth to organ dose or to integral air kerma. Examples of integral conversion factors from enamel dose to air kerma are given for several photon fluences specific for the Mayak reprocessing plant in Russia. The integral conversion factors are strongly affected by the energy and angular distributions of photon fluence, which are important characteristics of an exposure scenario for reconstruction of individual occupational doses. (orig.)

  2. Measurement of conversion coefficients between air Kerma and personal dose equivalent and backscatter factors for diagnostic X-ray beams; Determinacao experimental dos coeficientes de conversao de Kerma no ar para o equivalente de dose pessoal, Hp(d), e fatores de retroespalhamento em feixes de raios-x diagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Rosado, Paulo Henrique Goncalves

    2008-07-01

    Two sets of quantities are import in radiological protection: the protection and operational quantities. Both sets can be related to basic physical quantities such as kerma through conversion coefficients. For diagnostic x-ray beams the conversion coefficients and backscatter factors have not been determined yet, those parameters are need for calibrating dosimeters that will be used to determine the personal dose equivalent or the entrance skin dose. Conversion coefficients between air kerma and personal dose equivalent and backscatter factors were experimentally determined for the diagnostic x-ray qualities RQR and RQA recommended by the International Electrotechnical Commission (IEC). The air kerma in the phantom and the mean energy of the spectrum were measured for such purpose. Harshaw LiF-100H thermoluminescent dosemeters (TLD) were used for measurements after being calibrated against an 180 cm{sup 3} Radcal Corporation ionization chamber traceable to a reference laboratory. A 300 mm x 300 mm x 150 mm polymethylmethacrylate (PMMA) slab phantom was used for deep-dose measurements. Tl dosemeters were placed in the central axis of the x-ray beam at 5, 10, 15, 25 and 35 mm depth in the phantom upstream the beam direction Another required parameter for determining the conversion coefficients from was the mean energy of the x-ray spectrum. The spectroscopy of x-ray beams was done with a CdTe semiconductor detector that was calibrated with {sup 133} Ba, {sup 241} Am and {sup 57} Co radiation sources. Measurements of the x-ray spectra were carried out for all RQR and RQA IEC qualities. Corrections due to the detector intrinsic efficiency, total energy absorption, escape fraction of the characteristic x-rays, Compton effect and attenuation in the detector were done aiming an the accurate determination of the mean energy. Measured x-ray spectra were corrected with the stripping method by using these response functions. The typical combined standard uncertainties of

  3. Radon progeny dose conversion coefficients for Chinese males and females

    Energy Technology Data Exchange (ETDEWEB)

    Yu, K.N. E-mail: peter.yu@city.edu.hk; Cheung, T.T.K.; Haque, A.K.M.M.; Nikezic, D.; Lau, B.M.F.; Vucic, D

    2001-07-01

    The airway dimensions for Caucasian males have been scaled by multiplying by factors 0.95 and 0.88 to give those for Chinese males and females, respectively. Employing the most recent data on physical and biological parameters, the radiation doses to the basal and secretory cells due to {alpha} particles from {sup 218}Po and {sup 214}Po, homogeneously distributed in the mucous layer, have been calculated. The emission of {alpha} particles has been simulated by a Monte Carlo method. For both basal and secretory cells, the dose conversion coefficients (DCCs) for physical conditions of sleep, rest, light and heavy exercise, have been obtained for Chinese males and females for unattached progeny, and for attached progeny of diameters 0.02, 0.15, 0.25, 0.30 and 0.50 {mu}m. For basal cells, the coefficients lie in the range 0.69-6.82 mGy/(J s/m{sup 3}) or 8.7-86 mGy/WLM for unattached progeny and in the range 0.045-1.98 mGy/(J s/m{sup 3}) or 0.57-25 mGy/WLM for attached progeny. The corresponding ranges for Caucasian males are 1.27-8.81 mGy/(J s/m{sup 3}) or 16-111 mGy/WLM{sup -1} and 0.05-2.30 mGy/(J s/m{sup 3}) or 0.64-29 mGy/WLM. For secretory cells, the coefficients lie in the range 0.095-16.82 mGy/(J s/m{sup 3}) (1.2-212 mGy/WLM) for unattached progeny and in the range 0.095-6.67 mGy/(J s/m{sup 3}) (1.2-84 mGy/WLM) for attached progeny. The corresponding ranges for Caucasian males are 0.34-21.51 mGy/(J s/m{sup 3}) (4.3-271 mGy/WLM) and 0.1-7.78 mGy/(J s/m{sup 3}) (1.3-98 mGy/WLM). The overall DCCs calculated for a typical home environment are 0.59 and 0.52 mSv/(J s/m{sup 3}) (7.4 and 6.5 mSv/WLM) for Chinese males and females, respectively, which are 80 and 70% of the value, 0.73 mSv/(J s/m{sup 3}) (9.2 mSv/WLM), for Caucasian males.

  4. Solid-state personal dosimeter using dose conversion algorithm

    International Nuclear Information System (INIS)

    Lee, B.J.; Lee, Wanno; Cho, Gyuseong; Chang, S.Y.; Rho, S.R.

    2003-01-01

    Solid-state personal dosimeters using semiconductor detectors have been widely used because of their simplicity and real time operation. In this paper, a personal dosimeter based on a silicon PIN photodiode has been optimally designed by the Monte Carlo method and also developed. For performance test, the developed dosimeter was irradiated within the energy range between 50 keV and 1.25 MeV, the exposure dose rate between 3 mR/h and 25 R/h. The thickness of 0.2 mm Cu and 1.0 mm Al was selected as an optimal filter by simulation results. For minimizing the non-linear sensitivity on energy, dose conversion algorithm was presented, which was able to consider pulse number as well as pulse amplitude related to absorbed energies. The sensitivities of dosimeters developed by the proposed algorithm and the conventional method were compared and analyzed in detail. When dose conversion algorithm was used, the linearity of sensitivity was better about 38%. This dosimeter will be used for above 65 keV within the relative response of ±10% to 137 Cs

  5. Conversion from tooth enamel dose to organ doses for electron spin resonance dosimetry

    International Nuclear Information System (INIS)

    Takahashi, Fumiaki; Yamaguchi, Yasuhiro; Saito, Kimiaki; Hamada, Tatsuji

    2002-01-01

    Conversion from tooth enamel dose to organ doses was analyzed to establish a method of retrospective individual dose assessment against external photon exposure by electron spin resonance (ESR) dosimetry. Dose to tooth enamel was obtained by Monte Carlo calculations using a modified MIRD-type phantom with a teeth part. The calculated tooth enamel doses were verified by measurements with thermo-luminescence dosimeters inserted in a physical head phantom. Energy and angular dependences of tooth enamel dose were compared with those of other organ doses. Additional Monte Carlo calculations were performed to study the effect of human model on the tooth enamel dose with a voxel-type phantom, which was based on computed tomography images of the physical phantom. The data derived with the modified MIRD-type phantom were applied to convert from tooth enamel dose to organ doses against external photon exposure in a hypothesized field, where scattered radiation was taken into account. The results indicated that energy distribution of photons incident to a human body is required to evaluate precisely an individual dose based on ESR dosimetry for teeth. (author)

  6. Overview of the ICRP/ICRU adult reference computational phantoms and dose conversion coefficients for external idealised exposures

    CERN Document Server

    Endo, A; Zankl, M; Bolch, W E; Eckerman, K F; Hertel, N E; Hunt, J G; Pelliccioni, M; Schlattl, H; Menzel, H-G

    2014-01-01

    This paper reviews the ICRP Publications 110 and 116 describing the reference computational phantoms and dose conversion coefficients for external exposures. The International Commission on Radiological Protection (ICRP) in its 2007 Recommendations made several revisions to the methods of calculation of the protection quantities. In order to implement these recommendations, the DOCAL task group of the ICRP developed computational phantoms representing the reference adult male and female and then calculated a set of dose conversion coefficients for various types of idealised external exposures. This paper focuses on the dose conversion coefficients for neutrons and investigates their relationship with the conversion coefficients of the protection and operational quantities of ICRP Publication 74. Contributing factors to the differences between these sets of conversion coefficients are discussed in terms of the changes in phantoms employed and the radiation and tissue weighting factors.

  7. Application of the dose rate spectroscopy to the dose-to-curie conversion method using a NaI(Tl) detector

    International Nuclear Information System (INIS)

    JI, Young-Yong; Chung, Kun Ho; Kim, Chang-Jong; Kang, Mun Ja; Park, Sang Tae

    2015-01-01

    Dose rate spectroscopy is a very useful method to directly calculate the individual dose rate from the converted energy spectrum for the dose rate using the G-factor which is related to the used detector response function. A DTC conversion method for the estimation of the radioactivity based on the measured dose rate from the radioactive materials can then be modified into a simple equation using the dose rate spectroscopy. In order to make the method validation of the modified DTC conversion method, experimental verifications using a 3″φx3″ NaI(Tl) detector were conducted at the simple geometry of the point source located onto a detector and more complex geometries which mean the assay of the simulated radioactive material. In addition, the linearity about the results from the modified DTC conversion method was also estimated by increasing the distance between source positions and a detector to confirm the method validation in the energy, dose rate, and distance range of the gamma nuclides. - Highlights: • A modified DTC conversion method using the dose rate spectroscopy was established. • In-situ calibration factors were calculated from the MCNP simulation. • Radioactivities of the disk sources were accurately calculated using a modified DTC conversion method. • A modified DTC conversion method was applied to the assay of the radioactive material

  8. Dose conversion coefficients for electron exposure of the human eye lens

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G; Zankl, M

    2009-01-01

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. Two questions arise from this situation: first, which dose quantity is related to the risk of developing a cataract, and second, which personal dose equivalent quantity is appropriate for monitoring this dose quantity. While the dose equivalent quantity H p (0.07) has often been seen as being sufficiently accurate for monitoring the dose to the lens of the eye, this would be questionable in the case when the dose limits were reduced and, thus, it may be necessary to generally use the dose equivalent quantity H p (3) for this purpose. The basis for a decision, however, must be the knowledge of accurate conversion coefficients from fluence to equivalent dose to the lens. This is especially important for low-penetrating radiation, for example, electrons. Formerly published values of conversion coefficients are based on quite simple models of the eye. In this paper, quite a sophisticated model of the eye including the inner structure of the lens was used for the calculations and precise conversion coefficients for electrons with energies between 0.2 MeV and 12 MeV, and for angles of radiation incidence between 0 deg. and 45 deg. are presented. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are up to 1000 times smaller for electron energies below 1 MeV, nearly equal at 1 MeV and above 4 MeV, and by a factor of 1.5 larger at about 1.5 MeV electron energy.

  9. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, So Ra; Min, Byung Il; Park, Kihyun; Yang, Byung Mo; Suh, Kyung Suk [Nuclear Environmental Safety Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-12-15

    The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment.

  10. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR

    International Nuclear Information System (INIS)

    Kim, So Ra; Min, Byung Il; Park, Kihyun; Yang, Byung Mo; Suh, Kyung Suk

    2016-01-01

    The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment

  11. Isobio software: biological dose distribution and biological dose volume histogram from physical dose conversion using linear-quadratic-linear model.

    Science.gov (United States)

    Jaikuna, Tanwiwat; Khadsiri, Phatchareewan; Chawapun, Nisa; Saekho, Suwit; Tharavichitkul, Ekkasit

    2017-02-01

    To develop an in-house software program that is able to calculate and generate the biological dose distribution and biological dose volume histogram by physical dose conversion using the linear-quadratic-linear (LQL) model. The Isobio software was developed using MATLAB version 2014b to calculate and generate the biological dose distribution and biological dose volume histograms. The physical dose from each voxel in treatment planning was extracted through Computational Environment for Radiotherapy Research (CERR), and the accuracy was verified by the differentiation between the dose volume histogram from CERR and the treatment planning system. An equivalent dose in 2 Gy fraction (EQD 2 ) was calculated using biological effective dose (BED) based on the LQL model. The software calculation and the manual calculation were compared for EQD 2 verification with pair t -test statistical analysis using IBM SPSS Statistics version 22 (64-bit). Two and three-dimensional biological dose distribution and biological dose volume histogram were displayed correctly by the Isobio software. Different physical doses were found between CERR and treatment planning system (TPS) in Oncentra, with 3.33% in high-risk clinical target volume (HR-CTV) determined by D 90% , 0.56% in the bladder, 1.74% in the rectum when determined by D 2cc , and less than 1% in Pinnacle. The difference in the EQD 2 between the software calculation and the manual calculation was not significantly different with 0.00% at p -values 0.820, 0.095, and 0.593 for external beam radiation therapy (EBRT) and 0.240, 0.320, and 0.849 for brachytherapy (BT) in HR-CTV, bladder, and rectum, respectively. The Isobio software is a feasible tool to generate the biological dose distribution and biological dose volume histogram for treatment plan evaluation in both EBRT and BT.

  12. Overview of the ICRP/ICRU adult reference computational phantoms and dose conversion coefficients for external idealised exposures

    International Nuclear Information System (INIS)

    Endo, Akira; Petoussi-Henss, Nina; Zankl, Maria; Schlattl, Helmut; Bolch, Wesley E.; Eckerman, Keith F.; Hertel, Nolan E.; Hunt, John G.; Pelliccioni, Maurizio; Menzel, Hans-Georg

    2014-01-01

    This paper reviews the ICRP Publications 110 and 116 describing the reference computational phantoms and dose conversion coefficients for external exposures. The International Commission on Radiological Protection (ICRP) in its 2007 Recommendations made several revisions to the methods of calculation of the protection quantities. In order to implement these recommendations, the DOCAL task group of the ICRP developed computational phantoms representing the reference adult male and female and then calculated a set of dose conversion coefficients for various types of idealised external exposures. This paper focuses on the dose conversion coefficients for neutrons and investigates their relationship with the conversion coefficients of the protection and operational quantities of ICRP Publication 74. Contributing factors to the differences between these sets of conversion coefficients are discussed in terms of the changes in phantoms employed and the radiation and tissue weighting factors. This paper briefly reviews the reference computational phantoms and dose conversion coefficients for external exposures that were published jointly by ICRP and ICRU. Both these publications appeared as a consequence of the ICRP 2007 Recommendations; to implement these recommendations, the ICRP has developed reference computational phantoms representing the adult male and female. These phantoms are used to calculate reference dose conversion coefficients for external and internal sources. Using the reference phantoms and methodology consistent with the 2007 Recommendations, dose conversion coefficients for both effective doses and organ-absorbed doses for various types of idealised external exposures have been calculated. These data sets supersede the existing ICRP/ICRU data sets and expand the particle types and energy ranges. For neutrons, the new effective dose conversion coefficients become smaller compared with those in ICRP74, for energies below hundreds of keV. This is mainly

  13. Target dose conversion modeling from pencil beam (PB) to Monte Carlo (MC) for lung SBRT

    International Nuclear Information System (INIS)

    Zheng, Dandan; Zhu, Xiaofeng; Zhang, Qinghui; Liang, Xiaoying; Zhen, Weining; Lin, Chi; Verma, Vivek; Wang, Shuo; Wahl, Andrew; Lei, Yu; Zhou, Sumin; Zhang, Chi

    2016-01-01

    A challenge preventing routine clinical implementation of Monte Carlo (MC)-based lung SBRT is the difficulty of reinterpreting historical outcome data calculated with inaccurate dose algorithms, because the target dose was found to decrease to varying degrees when recalculated with MC. The large variability was previously found to be affected by factors such as tumour size, location, and lung density, usually through sub-group comparisons. We hereby conducted a pilot study to systematically and quantitatively analyze these patient factors and explore accurate target dose conversion models, so that large-scale historical outcome data can be correlated with more accurate MC dose without recalculation. Twenty-one patients that underwent SBRT for early-stage lung cancer were replanned with 6MV 360° dynamic conformal arcs using pencil-beam (PB) and recalculated with MC. The percent D95 difference (PB-MC) was calculated for the PTV and GTV. Using single linear regression, this difference was correlated with the following quantitative patient indices: maximum tumour diameter (MaxD); PTV and GTV volumes; minimum distance from tumour to soft tissue (dmin); and mean density and standard deviation of the PTV, GTV, PTV margin, lung, and 2 mm, 15 mm, 50 mm shells outside the PTV. Multiple linear regression and artificial neural network (ANN) were employed to model multiple factors and improve dose conversion accuracy. Single linear regression with PTV D95 deficiency identified the strongest correlation on mean-density (location) indices, weaker on lung density, and the weakest on size indices, with the following R 2 values in decreasing orders: shell2mm (0.71), PTV (0.68), PTV margin (0.65), shell15mm (0.62), shell50mm (0.49), lung (0.40), dmin (0.22), GTV (0.19), MaxD (0.17), PTV volume (0.15), and GTV volume (0.08). A multiple linear regression model yielded the significance factor of 3.0E-7 using two independent features: mean density of shell2mm (P = 1.6E-7) and PTV volume

  14. Dose conversion coefficients for photon exposure of the human eye lens

    Science.gov (United States)

    Behrens, R.; Dietze, G.

    2011-01-01

    In recent years, several papers dealing with the eye lens dose have been published, because epidemiological studies implied that the induction of cataracts occurs even at eye lens doses of less than 500 mGy. Different questions were addressed: Which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens? Is a new definition of the dose quantity Hp(3) based on a cylinder phantom to represent the human head necessary? Are current conversion coefficients from fluence to equivalent dose to the lens sufficiently accurate? To investigate the latter question, a realistic model of the eye including the inner structure of the lens was developed. Using this eye model, conversion coefficients for electrons have already been presented. In this paper, the same eye model—with the addition of the whole body—was used to calculate conversion coefficients from fluence (and air kerma) to equivalent dose to the lens for photon radiation from 5 keV to 10 MeV. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are similar between 40 keV and 1 MeV and lower by up to a factor of 5 and 7 for photon energies at about 10 keV and 10 MeV, respectively. Above 1 MeV, the new values (calculated without kerma approximation) should be applied in pure photon radiation fields, while the values adopted by the ICRP in 1996 (calculated with kerma approximation) should be applied in case a significant contribution from secondary electrons originating outside the body is present.

  15. Dose conversion coefficients for photon exposure of the human eye lens

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G

    2011-01-01

    In recent years, several papers dealing with the eye lens dose have been published, because epidemiological studies implied that the induction of cataracts occurs even at eye lens doses of less than 500 mGy. Different questions were addressed: Which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens? Is a new definition of the dose quantity H p (3) based on a cylinder phantom to represent the human head necessary? Are current conversion coefficients from fluence to equivalent dose to the lens sufficiently accurate? To investigate the latter question, a realistic model of the eye including the inner structure of the lens was developed. Using this eye model, conversion coefficients for electrons have already been presented. In this paper, the same eye model-with the addition of the whole body-was used to calculate conversion coefficients from fluence (and air kerma) to equivalent dose to the lens for photon radiation from 5 keV to 10 MeV. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are similar between 40 keV and 1 MeV and lower by up to a factor of 5 and 7 for photon energies at about 10 keV and 10 MeV, respectively. Above 1 MeV, the new values (calculated without kerma approximation) should be applied in pure photon radiation fields, while the values adopted by the ICRP in 1996 (calculated with kerma approximation) should be applied in case a significant contribution from secondary electrons originating outside the body is present.

  16. Psychosocial Factors in Children and Adolescents with Conversion Disorder

    Science.gov (United States)

    Sharma, I.; Giri, D.; Dutta, Anna; Mazumder, P.

    2005-01-01

    Introduction: In view of the limited studies on the psychosocial environment of children presenting with conversion disorders, the present study was carried out to study the psychosocial factors in children with conversion disorders. Method: 40 patients of Conversion Disorder, who presented with "pseudo seizures" and were diagnosed…

  17. Internal Dose Conversion Coefficients of Domestic Reference Animal and Plants for Dose Assessment of Non-human Species

    International Nuclear Information System (INIS)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Choi, Yong Ho

    2009-01-01

    Traditionally, radiation protection has been focused on a radiation exposure of human beings. In the international radiation protection community, one of the recent key issues is to establish the methodology for assessing the radiological impact of an ionizing radiation on non-human species for an environmental protection. To assess the radiological impact to non-human species dose conversion coefficients are essential. This paper describes the methodology to calculate the internal dose conversion coefficient for non-human species and presents calculated internal dose conversion coefficients of 25 radionuclides for 8 domestic reference animal and plants

  18. Factors affecting calculations of dose resulting from a tritium release into the atmosphere

    International Nuclear Information System (INIS)

    Otaduy, P.; Easterly, C.E.; Booth, R.S.; Jacobs, D.G.

    1976-01-01

    Tritium releases in the form of HT represent a lower hazard to man than releases as HTO. However, during movement in the environment, HT is converted into HTO. The effects of the conversion rate on calcultions of dose are described, and a general method is presented for determining the dose from tritium for various conversion rates and relative HTO/HT risk factors

  19. Factors affecting patient dose in diagnostic radiology

    International Nuclear Information System (INIS)

    Poletti, J.L.

    1985-01-01

    There are two stages in the X-ray image forming process; first the irradiation of the patient to produce the X-ray pattern in space, known as the primary radiological image, and second, the conversion of this pattern into a visible form. This report discusses the first stage and its interrelation with image quality and patient dose

  20. 42 CFR 414.30 - Conversion factor update.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Conversion factor update. 414.30 Section 414.30... Practitioners § 414.30 Conversion factor update. Unless Congress acts in accordance with section 1848(d)(3) of... preceding FY over the third preceding FY exceeds the performance standard rate of increase established for...

  1. The conversion of exposures due to radon into the effective dose: the epidemiological approach

    Energy Technology Data Exchange (ETDEWEB)

    Beck, T.R. [Federal Office for Radiation Protection, Berlin (Germany)

    2017-11-15

    The risks and dose conversion coefficients for residential and occupational exposures due to radon were determined with applying the epidemiological risk models to ICRP representative populations. The dose conversion coefficient for residential radon was estimated with a value of 1.6 mSv year{sup -1} per 100 Bq m{sup -3} (3.6 mSv per WLM), which is significantly lower than the corresponding value derived from the biokinetic and dosimetric models. The dose conversion coefficient for occupational exposures with applying the risk models for miners was estimated with a value of 14 mSv per WLM, which is in good accordance with the results of the dosimetric models. To resolve the discrepancy regarding residential radon, the ICRP approaches for the determination of risks and doses were reviewed. It could be shown that ICRP overestimates the risk for lung cancer caused by residential radon. This can be attributed to a wrong population weighting of the radon-induced risks in its epidemiological approach. With the approach in this work, the average risks for lung cancer were determined, taking into account the age-specific risk contributions of all individuals in the population. As a result, a lower risk coefficient for residential radon was obtained. The results from the ICRP biokinetic and dosimetric models for both, the occupationally exposed working age population and the whole population exposed to residential radon, can be brought in better accordance with the corresponding results of the epidemiological approach, if the respective relative radiation detriments and a radiation-weighting factor for alpha particles of about ten are used. (orig.)

  2. The conversion of exposures due to radon into the effective dose: the epidemiological approach

    International Nuclear Information System (INIS)

    Beck, T.R.

    2017-01-01

    The risks and dose conversion coefficients for residential and occupational exposures due to radon were determined with applying the epidemiological risk models to ICRP representative populations. The dose conversion coefficient for residential radon was estimated with a value of 1.6 mSv year -1 per 100 Bq m -3 (3.6 mSv per WLM), which is significantly lower than the corresponding value derived from the biokinetic and dosimetric models. The dose conversion coefficient for occupational exposures with applying the risk models for miners was estimated with a value of 14 mSv per WLM, which is in good accordance with the results of the dosimetric models. To resolve the discrepancy regarding residential radon, the ICRP approaches for the determination of risks and doses were reviewed. It could be shown that ICRP overestimates the risk for lung cancer caused by residential radon. This can be attributed to a wrong population weighting of the radon-induced risks in its epidemiological approach. With the approach in this work, the average risks for lung cancer were determined, taking into account the age-specific risk contributions of all individuals in the population. As a result, a lower risk coefficient for residential radon was obtained. The results from the ICRP biokinetic and dosimetric models for both, the occupationally exposed working age population and the whole population exposed to residential radon, can be brought in better accordance with the corresponding results of the epidemiological approach, if the respective relative radiation detriments and a radiation-weighting factor for alpha particles of about ten are used. (orig.)

  3. Spectrum-to-dose conversion operator value function of a Ge(Li) in-situ environmental gamma-ray spectrometer

    International Nuclear Information System (INIS)

    Terada, Hiromi; Sakai, Eiji; Katagiri, Masaki

    1976-05-01

    A spectrum-to-dose conversion operator value function was obtained for a 73cm 3 closed-end coaxial Ge(Li) in-situ environmental gamma-ray spectrometer; factors influencing the function are considered. (auth.)

  4. Dose conversion coefficients calculated using a series of adult Japanese voxel phantoms against external photon exposure

    International Nuclear Information System (INIS)

    Sato, Kaoru; Endo, Akira; Saito, Kimiaki

    2008-10-01

    This report presents a complete set of conversion coefficients of organ doses and effective doses calculated for external photon exposure using five Japanese adult voxel phantoms developed at the Japan Atomic Energy Agency (JAEA). At the JAEA, high-resolution Japanese voxel phantoms have been developed to clarify the variation of organ doses due to the anatomical characteristics of Japanese, and three male phantoms (JM, JM2 and Otoko) and two female phantoms (JF and Onago) have been constructed up to now. The conversion coefficients of organ doses and effective doses for the five voxel phantoms have been calculated for six kinds of idealized irradiation geometries from monoenergetic photons ranging from 0.01 to 10 MeV using EGS4, a Monte Carlo code for the simulation of coupled electron-photon transport. The dose conversion coefficients are given as absorbed dose and effective dose per unit air-kerma free-in-air, and are presented in tables and figures. The calculated dose conversion coefficients are compared with those of voxel phantoms based on the Caucasian and the recommended values in ICRP74 in order to discuss (1) variation of organ dose due to the body size and individual anatomy, such as position and shape of organs, and (2) effect of posture on organ doses. The present report provides valuable data to study the influence of the body characteristics of Japanese upon the organ doses and to discuss developing reference Japanese and Asian phantoms. (author)

  5. Local organ dose conversion coefficients for angiographic examinations of coronary arteries

    International Nuclear Information System (INIS)

    Schlattl, H; Zankl, M; Hausleiter, J; Hoeschen, C

    2007-01-01

    New organ dose conversion coefficients for coronary angiographic interventions are presented, as well as dose distributions and resulting maximal local dose conversion coefficients in the relevant organs. For the Monte Carlo based simulations, voxel models of the human anatomy were employed which represent the average Caucasian adult man and woman as defined by the International Commission on Radiological Protection. In the 21 investigated projections, the mean organ dose conversion coefficients vary from a few 0.01 to 2 mGy(Gy cm 2 ) -1 , depending on the projections. However, especially in portions of the lungs and the active bone marrow, the conversion coefficients can locally amount up to 10 mGy(Gy cm 2 ) -1 , which is half the average conversion coefficient of the skin at the field entrance. In addition to the dose conversion coefficients, the dependence of the patient dose on the projection has been estimated. It could be shown that the patient doses are highest for left anterior oblique views with strong caudal or cranial orientation. Nevertheless, for a large range of image-intensifier positions no significant dose differences could be found

  6. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations.

    Science.gov (United States)

    Nogueira, P; Zankl, M; Schlattl, H; Vaz, P

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  7. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    International Nuclear Information System (INIS)

    Nogueira, P; Vaz, P; Zankl, M; Schlattl, H

    2011-01-01

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  8. Absorbed dose conversion coefficients for embryo and foetus in neutron fields

    International Nuclear Information System (INIS)

    Chen, J.

    2007-01-01

    The Monte Carlo code MCNPX has been used to determine mean absorbed doses to the embryo and foetus when the mother is exposed to neutron fields. There are situations, such as on-board aircraft, where high-energy neutrons are often peaked in top down (TOP) direction. In addition to previous publications for standard irradiation geometries, this study provides absorbed dose conversion coefficients for the embryo of 8 weeks and the foetus of 3, 6 or 9 months at TOP irradiation geometry. The conversion coefficients are compared with the coefficients in isotropic irradiation (ISO). With increasing neutron energies, the conversion coefficients in TOP irradiation become dominant. A set of conversion coefficients is constructed from the higher value in either ISO or TOP irradiation at a given neutron energy. In cases where the irradiation geometry is not adequately known, this set of conversion coefficients can be used in a conservative dose assessment for embryo and foetus in neutron fields. (authors)

  9. ESTIMATION OF THE CONVERSION COEFFICIENTS FROM DOSE-AREA PRODUCT TO EFFECTIVE DOSE FOR BARIUM MEAL EXAMINATIONS FOR ADULT PATIENTS

    Directory of Open Access Journals (Sweden)

    A. V. Vodovatov

    2018-01-01

    Full Text Available Fluoroscopic examinations of the upper gastro-intestinal tract and, especially, barium meal examinations, are commonly performed in a majority of hospitals. These examinations are associated both with substantial individual patient doses and contribution to the collective dose from medical exposure. Effective dose estimation for this type of examinations is complicated due to: 1 the necessity to simulate the moving X-ray irradiation field; 2 differences in study structure for the individual patients; 3 subjectivity of the operators; and 4 differences in the X-ray equipment. The aim of the current study was to estimate conversion coefficients from dose-area product to effective dose for barium meal examinations for the over couch and under couch exposure conditions. The study was based on data collected in the X-ray unit of the surgical department of the St-Petersburg Mariinsky hospital. A model of patient exposure during barium meal examination was developed based on the collected data on fluoroscopy protocols and adult patient irradiation geometry. Conversion coefficients were calculated using PCXMC 2.0 software. Complete examinations were converted into a set of typical fluoroscopy phases and X-ray images, specified by the examined anatomical region and the projection of patient exposure. Conversion coefficients from dose-area product to effective dose were calculated for each phase of the examination and for the complete examination. The resulting values of the conversion coefficients are comparable with published data. Variations in the absolute values of the conversion coefficients can be explained by differences in clinical protocols, models for the estimation of the effective dose and parameters of barium meal examinations. The proposed approach for estimation of effective dose considers such important features of fluoroscopic examinations as: 1 non-uniform structure of examination, 2 significant movement of the X-ray tube within a single

  10. Hollywood's Conversion to Color: The Technological, Economic and Aesthetic Factors.

    Science.gov (United States)

    Kindem, Forham A.

    1979-01-01

    Discusses the film industry's conversion to color cinematography in the period between the 1920s and 1960s. Cites economic considerations, technological modifications, and aesthetic preferences by audiences as factors in this development. (JMF)

  11. Factors determining conversion of laparoscopic to open cholecystectomy

    Directory of Open Access Journals (Sweden)

    Tapash Kumar Maitra

    2017-07-01

    Full Text Available Background and objectives:Laparoscopic cholecystectomy (LC has virtually replaced conventional open cholecystectomy (OC as the standard procedure of treatment for cholelithiasis and cholecystitis. However, OC sometimes becomes a necessity considering the feasibility and safety of the surgical procedure. But the factors that demand conversion from LC to OC differ widely. The present study aimed to determine the prevalence of conversion from LC to OC and to assess the causes of conversion and risk factors related to conversion. Methods: The study was conducted in a referral hospital – ‘Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorder (BIRDEM’ from September 2014 to September 2016. Cases of cholelithiasis with or without cholecystitis, and other gall bladder pathology were included in the study. A team of experienced surgeon performed LC of all selected cases. The causes of conversion to OC were systematically recorded by the surgical team and the risk factors (age, sex, obesity, history of previous abdominal surgery, gallbladder thickness related to conversion from LC to OC was investigated. Results: A total of 261 (M / F = 87 /174 patients were considered eligible for the study. The mean age of all patients was 43 (±1.75 years. For the male and female groups the mean ages were 44±1.9 and 42±1.6 years respectively. Of the total 261 cases, 210 (80.5% patients had cholelithiasis with chronic cholecystitis, 47 (18.0% had gallbladder stone plus acute cholecystitis and 4 (1.5% had gallbladder polyp. Open conversion was required in case of 19 patients. Thus, overall conversion rate was 7.3%. The common causes of conversion were a difficulty in defining Calot’s triangle (42.1%, b injury to cystic artery (21.1% and c injury to bile duct (15.8%. Both male and female had equal risk for conversion. The investigated risk factors like history of previous abdominal surgery, preoperative ERCP, acute

  12. Determination of conversion factors of kerma and fluence to ambient dose equivalent for X-rays generated between 50 kV{sub p} to 125 kV{sub p}; Determinacao dos fatores de conversao de kerma no ar e de fluencia para o equivalente de dose ambiental para raios-X gerados no intervalo de 50 kV{sub p} a 125 kV{sub p}

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Maria do Socorro

    1997-12-31

    The ambient dose equivalent was determined experimentally on the interval of energy of X ray applied in diagnostic radiology. A PMMA sphere was used to simulate the trunk human (phantom), based on the definition of the report ICRU 39. The absorbed dose in different positions in the phantom was determined using LiF-TLD 100. The X ray spectra were measured with a high-purity germanium detector (HP Ge). It was also determined the HVL and the effective energy in this energy range. The conversion coefficient of the K{sub air} and {Phi} to H{sup *}(d) were determined to 10, 50 and 60 mm deep in the PMMA sphere. The obtained values were compared with data of the literature. The maximum uncertainty obtained for the coefficients was 7.2%. All parameters were also determined to the X ray quality of the incident and transmitted beam by the patient, according to the recommendation of the standard DIN 6872. The conversion factor was calculated for those situations where the X-ray beam is transmitted by a layer and Pb and it is necessary to estimate the effective dose, as in the case of shielding project of radiology diagnosis room. (author) 51 refs., 35 figs., 15 tabs.

  13. Determination of conversion factors of kerma and fluence to ambient dose equivalent for X-rays generated between 50 kV{sub p} to 125 kV{sub p}; Determinacao dos fatores de conversao de kerma no ar e de fluencia para o equivalente de dose ambiental para raios-X gerados no intervalo de 50 kV{sub p} a 125 kV{sub p}

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Maria do Socorro

    1998-12-31

    The ambient dose equivalent was determined experimentally on the interval of energy of X ray applied in diagnostic radiology. A PMMA sphere was used to simulate the trunk human (phantom), based on the definition of the report ICRU 39. The absorbed dose in different positions in the phantom was determined using LiF-TLD 100. The X ray spectra were measured with a high-purity germanium detector (HP Ge). It was also determined the HVL and the effective energy in this energy range. The conversion coefficient of the K{sub air} and {Phi} to H{sup *}(d) were determined to 10, 50 and 60 mm deep in the PMMA sphere. The obtained values were compared with data of the literature. The maximum uncertainty obtained for the coefficients was 7.2%. All parameters were also determined to the X ray quality of the incident and transmitted beam by the patient, according to the recommendation of the standard DIN 6872. The conversion factor was calculated for those situations where the X-ray beam is transmitted by a layer and Pb and it is necessary to estimate the effective dose, as in the case of shielding project of radiology diagnosis room. (author) 51 refs., 35 figs., 15 tabs.

  14. Absorbed Internal Dose Conversion Coefficients for Domestic Reference Animals and Plant

    Energy Technology Data Exchange (ETDEWEB)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Choi, Yong Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-02-15

    This paper describes the methodology of calculating the internal dose conversion coefficient in order to assess the radiological impact on non-human species. This paper also presents the internal dose conversion coefficients of 25 radionuclides ({sup 3}H, {sup 7}Be, {sup 14}C, {sup 40}K, {sup 51}Cr, {sup 54}Mn, {sup 59}Fe, {sup 58}Co, {sup 60}Co, {sup 65}Zn, {sup 90}Sr, '9{sup 5}Zr, {sup 95}Nb, {sup 99}Tc, {sup 106}Ru, {sup 129}I, {sup 131}I, {sup 136}Cs, {sup 137}Cs, {sup 140}Ba, {sup 140}La, {sup 144}Ce, {sup 238}U, {sup 239}Pu, {sup 240}Pu) for domestic seven reference animals (roe deer, rat, frog, snake, Chinese minnow, bee, and earthworm) and one reference plant (pine tree). The uniform isotropic model was applied in order to calculate the internal dose conversion coefficients. The calculated internal dose conversion coefficient (muGyd{sup -1} per Bqkg{sup -1}) ranged from 10{sup -6} to 10{sup -2} according to the type of radionuclides and organisms studied. It turns out that the internal does conversion coefficient was higher for alpha radionuclides, such as {sup 238}U, {sup 239}Pu, and {sup 240}Pu, and for large organisms, such as roe deer and pine tree. The internal dose conversion coefficients of {sup 239}Pu, {sup 240}Pu, {sup 238}U, {sup 14}C, {sup 3}H and {sup 99}Tc were independent of the organism

  15. Dose conversion coefficients for paediatric CT examinations with automatic tube current modulation

    International Nuclear Information System (INIS)

    Schlattl, H; Zankl, M; Becker, J; Hoeschen, C

    2012-01-01

    A common dose-saving technique used in modern CT devices is automatic tube current modulation (TCM), which was originally designed to also reduce the dose in paediatric CT patients. In order to be able to deduce detailed organ doses of paediatric models, dose conversion coefficients normalized to CTDI vol for an eight-week-old baby and seven- and eight-year-old children have been computed accounting for TCM. The relative difference in organ dose conversion coefficients with and without TCM is for many organs and examinations less than 10%, but can in some cases amount up to 30%, e.g., for the thyroid in the chest CT of the seven-year-old child. Overall, the impact of TCM on the conversion coefficients increases with increasing age. Besides TCM, also the effect of collimation and tube voltage on organ dose conversion coefficients has been investigated. It could be shown that the normalization to CTDI vol leads to conversion coefficients that can in most cases be considered to be independent of collimation and tube voltage. (paper)

  16. The fitting parameters extraction of conversion model of the low dose rate effect in bipolar devices

    International Nuclear Information System (INIS)

    Bakerenkov, Alexander

    2011-01-01

    The Enhanced Low Dose Rate Sensitivity (ELDRS) in bipolar devices consists of in base current degradation of NPN and PNP transistors increase as the dose rate is decreased. As a result of almost 20-year studying, the some physical models of effect are developed, being described in detail. Accelerated test methods, based on these models use in standards. The conversion model of the effect, that allows to describe the inverse S-shaped excess base current dependence versus dose rate, was proposed. This paper presents the problem of conversion model fitting parameters extraction.

  17. Methods for calculating dose conversion coefficients for terrestrial and aquatic biota

    International Nuclear Information System (INIS)

    Ulanovsky, A.; Proehl, G.; Gomez-Ros, J.M.

    2008-01-01

    Plants and animals may be exposed to ionizing radiation from radionuclides in the environment. This paper describes the underlying data and assumptions to assess doses to biota due to internal and external exposure for a wide range of masses and shapes living in various habitats. A dosimetric module is implemented which is a user-friendly and flexible possibility to assess dose conversion coefficients for aquatic and terrestrial biota. The dose conversion coefficients have been derived for internal and various external exposure scenarios. The dosimetric model is linked to radionuclide decay and emission database, compatible with the ICRP Publication 38, thus providing a capability to compute dose conversion coefficients for any nuclide from the database and its daughter nuclides. The dosimetric module has been integrated into the ERICA Tool, but it can also be used as a stand-alone version

  18. Determination of fluence-to-dose conversion coefficients by means of artificial neural networks

    International Nuclear Information System (INIS)

    Soto B, T. G.; Rivera P, E.; De Leon M, H. A.; Hernandez D, V. M.; Vega C, H. R.; Gallego, E.; Lorente, A.

    2012-10-01

    In this paper is presented an Artificial Neural Network (Ann) that has been designed, trained and validated to determinate the effective dose e, ambient dose equivalent h(10) and personal dose equivalent hp(10,θ) fluence-to-dose conversion coefficients at different positions, having as only input data 7 count rates obtained with a Bonner Sphere Spectrometer (Bss) system. A set of 211 neutron spectra and the fluence-to-dose conversion coefficients published by the International Atomic Energy Agency were used to train and validate the Ann. This set was divided into 2 subsets, one of 181 elements to train the Ann and the remaining 30 to validate it. The Ann was trained using Bss count rates as input data and the fluence-to-dose conversion coefficients as output data. The network was validated and tested with the set of 30 elements that were not used during the training process. Good results were obtained proving that Ann are a good choice for calculating the fluence-to-dose conversion coefficients having as only data the count rates obtained with a Bss. (Author)

  19. Conversion coefficients for determining organ doses in paediatric pelvis and hip joint radiography

    International Nuclear Information System (INIS)

    Seidenbusch, Michael C.; Schneider, Karl

    2014-01-01

    Knowledge of organ and effective doses achieved during paediatric X-ray examinations is an important prerequisite for assessment of radiation burden to the patient. Conversion coefficients for reconstruction of organ and effective doses from entrance doses for pelvis and hip joint radiographs of 0-, 1-, 5-, 10-, 15- and 30-year-old patients are provided regarding the Guidelines of Good Radiographic Technique of the European Commission. Using the personal computer program PCXMC developed by the Finnish Centre for Radiation and Nuclear Safety (Saeteilyturvakeskus STUK), conversion coefficients for conventional pelvis and hip joint radiographs were calculated by performing Monte Carlo simulations in mathematical hermaphrodite phantom models representing patients of different ages. The clinical variation of radiation field settings was taken into consideration by defining optimal and suboptimal standard field settings. Conversion coefficients for the reconstruction of organ doses in about 40 organs and tissues from measured entrance doses during pelvis and hip joint radiographs of 0-, 1-, 5-, 10-, 15- and 30-year-old patients were calculated for the standard sagittal beam projection and the standard focus detector distance of 115 cm. The conversion coefficients presented can be used for organ dose assessments from entrance doses measured during pelvis and hip joint radiographs of children and young adults with all field settings within the optimal and suboptimal standard field settings. (orig.)

  20. Determination of fluence-to-dose conversion coefficients by means of artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Soto B, T. G.; Rivera P, E.; De Leon M, H. A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Gallego, E.; Lorente, A., E-mail: tzinnia.soto@gmail.com [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, Jose Gutierrez Abascal No. 2, 28006 Madrid (Spain)

    2012-10-15

    In this paper is presented an Artificial Neural Network (Ann) that has been designed, trained and validated to determinate the effective dose e, ambient dose equivalent h(10) and personal dose equivalent hp(10,{theta}) fluence-to-dose conversion coefficients at different positions, having as only input data 7 count rates obtained with a Bonner Sphere Spectrometer (Bss) system. A set of 211 neutron spectra and the fluence-to-dose conversion coefficients published by the International Atomic Energy Agency were used to train and validate the Ann. This set was divided into 2 subsets, one of 181 elements to train the Ann and the remaining 30 to validate it. The Ann was trained using Bss count rates as input data and the fluence-to-dose conversion coefficients as output data. The network was validated and tested with the set of 30 elements that were not used during the training process. Good results were obtained proving that Ann are a good choice for calculating the fluence-to-dose conversion coefficients having as only data the count rates obtained with a Bss. (Author)

  1. Nitrogen-to-Protein Conversion Factors for Three Edible Insects

    NARCIS (Netherlands)

    Janssen, Renske H.; Vincken, Jean Paul; Broek, van den Lambertus A.M.; Fogliano, Vincenzo; Lakemond, Catriona M.M.

    2017-01-01

    Insects are considered a nutritionally valuable source of alternative proteins, and their efficient protein extraction is a prerequisite for large-scale use. The protein content is usually calculated from total nitrogen using the nitrogen-to-protein conversion factor (Kp) of 6.25. This factor

  2. Factors affecting patient dose in diagnostic radiology

    International Nuclear Information System (INIS)

    Poletti, J.L.

    1994-03-01

    The report, Factors Affecting Patient Dose in Diagnostic Radiology is divided into three main sections. Part one is introductory and covers the basic principles of x-ray production and image formation. It includes discussion of x-ray generators and x-ray tubes, radiation properties and units, specification and measurement of x-ray beams, methods of patient dose measurement, radiation effects, radiation protection philosophy and finally the essentials of imaging systems. Part two examines factors affecting the x-ray output of x-ray machines and the characteristics of x-ray beams. These include the influence of heat ratings, kVp, waveform, exposure timer, filtration, focus-film distance, beam intensity distribution, x-ray tube age and focal spot size. Part three examines x-ray machine, equipment and patient factors which affect the dose received by individual patients. The factors considered include justification of examinations, choice of examination method, film/screen combinations, kVp, mAs, focus-film distance, collimation and field size, exposure time, projection, scatter, generator calibration errors, waveform, filtration, film processing and patient size. The patient dose implications of fluoroscopy systems, CT scanners, special procedures and mammography are also discussed. The report concludes with a brief discussion of patient dose levels in New Zealand and dose optimisation. 104 refs., 32 figs., 27 tabs

  3. Neutron fluence-to-dose conversion coefficients for embryo and fetus

    International Nuclear Information System (INIS)

    Chen, J.; Meyerhof, D.; Vlahovich, S.

    2004-01-01

    A problem of concern in radiation protection is the exposure of pregnant women to ionising radiation, because of the high radiosensitivity of the embryo and fetus. External neutron exposure is of concern when pregnant women travel by aeroplane. Dose assessments for neutrons frequently rely on fluence-to-dose conversion coefficients. While neutron fluence-to-dose conversion coefficients for adults are recommended in International Commission on Radiological Protection publications and International Commission on Radiological Units and Measurements reports, conversion coefficients for embryos and fetuses are not given in the publications. This study undertakes Monte Carlo calculations to determine the mean absorbed doses to the embryo and fetus when the mother is exposed to neutron fields. A new set of mathematical models for the embryo and fetus has been developed at Health Canada and is used together with mathematical phantoms of a pregnant female developed at Oak Ridge National Laboratory. Monoenergetic neutrons from 1 eV to 10 MeV are considered in this study. The irradiation geometries include antero-posterior (AP), postero-anterior (PA), lateral (LAT), rotational (ROT) and isotropic (ISO) geometries. At each of these standard irradiation geometries, absorbed doses to the fetal brain and body are calculated; for the embryo at 8 weeks and the fetus at 3, 6 or 9 months. Neutron fluence-to-absorbed dose conversion coefficients are derived for the four age groups. Neutron fluence-to-equivalent dose conversion coefficients are given for the AP irradiations which yield the highest radiation dose to the fetal body in the neutron energy range considered here. The results indicate that for neutrons <10 MeV more protection should be given to pregnant women in the first trimester due to the higher absorbed dose per unit neutron fluence to the fetus. (authors)

  4. Neutron fluence-to-dose conversion coefficients for embryo and fetus.

    Science.gov (United States)

    Chen, Jing; Meyerhof, Dorothy; Vlahovich, Slavica

    2004-01-01

    A problem of concern in radiation protection is the exposure of pregnant women to ionising radiation, because of the high radiosensitivity of the embryo and fetus. External neutron exposure is of concern when pregnant women travel by aeroplane. Dose assessments for neutrons frequently rely on fluence-to-dose conversion coefficients. While neutron fluence-to-dose conversion coefficients for adults are recommended in International Commission on Radiological Protection publications and International Commission on Radiological Units and Measurements reports, conversion coefficients for embryos and fetuses are not given in the publications. This study undertakes Monte Carlo calculations to determine the mean absorbed doses to the embryo and fetus when the mother is exposed to neutron fields. A new set of mathematical models for the embryo and fetus has been developed at Health Canada and is used together with mathematical phantoms of a pregnant female developed at Oak Ridge National Laboratory. Monoenergetic neutrons from 1 eV to 10 MeV are considered in this study. The irradiation geometries include antero-posterior (AP), postero-anterior (PA), lateral (LAT), rotational (ROT) and isotropic (ISO) geometries. At each of these standard irradiation geometries, absorbed doses to the fetal brain and body are calculated; for the embryo at 8 weeks and the fetus at 3, 6 or 9 months. Neutron fluence-to-absorbed dose conversion coefficients are derived for the four age groups. Neutron fluence-to-equivalent dose conversion coefficients are given for the AP irradiations which yield the highest radiation dose to the fetal body in the neutron energy range considered here. The results indicate that for neutrons <10 MeV more protection should be given to pregnant women in the first trimester due to the higher absorbed dose per unit neutron fluence to the fetus.

  5. Personal dose equivalent conversion coefficients for electrons to 1 Ge V.

    Science.gov (United States)

    Veinot, K G; Hertel, N E

    2012-04-01

    In a previous paper, conversion coefficients for the personal dose equivalent, H(p)(d), for photons were reported. This note reports values for electrons calculated using similar techniques. The personal dose equivalent is the quantity used to approximate the protection quantity effective dose when performing personal dosemeter calibrations and in practice the personal dose equivalent is determined using a 30×30×15 cm slab-type phantom. Conversion coefficients to 1 GeV have been calculated for H(p)(10), H(p)(3) and H(p)(0.07) in the recommended slab phantom. Although the conversion coefficients were determined for discrete incident energies, analytical fits of the conversion coefficients over the energy range are provided using a similar formulation as in the photon results previously reported. The conversion coefficients for the personal dose equivalent are compared with the appropriate protection quantity, calculated according to the recommendations of the latest International Commission on Radiological Protection guidance. Effects of eyewear on H(p)(3) are also discussed.

  6. Simulation codes to evcaluate dose conversion coefficients for hadrons over 10 GeV

    International Nuclear Information System (INIS)

    Sato, T.; Tsuda, S.; Sakamoto, Y.; Yamaguchi, Y.; Niita, K.

    2002-01-01

    The conversion coefficients from fluence to effective dose for high energy hadrons are indispensable for various purposes such as accelerator shielding design and dose evaluation in space mission. Monte Carlo calculation code HETC-3STEP was used to evaluate dose conversion coefficients for neutrons and protons up to 10 GeV with an anthropomorphic model. The scaling model was incorporated in the code for simulation of high energy nuclear reactions. However, the secondary particle energy spectra predicted by the model were not smooth for nuclear reactions over several GeV. We attempted, therefore, to simulate transportation of such high energy particles by two newly developed Monte Carlo simulation codes: one is HETC-3STEP including the model used in EVENTQ instead of the scaling model, and the other is NMTC/JAM. By comparing calculated cross sections by these codes with experimental data for high energy nuclear reactions, it was found that NMTC/JAM had a better agreement with the data. We decided, therefore, to adopt NMTC/JAM for evaluation of dose conversion coefficients for hadrons with energies over 10 GeV. The effective dose conversion coefficients for high energy neutrons and protons evaluated by NMTC/JAM were found to be close to those by the FLUKA code

  7. Conversion from dose-to-graphite to dose-to-water in an 80 MeV/A carbon ion beam.

    Science.gov (United States)

    Rossomme, S; Palmans, H; Shipley, D; Thomas, R; Lee, N; Romano, F; Cirrone, P; Cuttone, G; Bertrand, D; Vynckier, S

    2013-08-21

    Based on experiments and numerical simulations, a study is carried out pertaining to the conversion of dose-to-graphite to dose-to-water in a carbon ion beam. This conversion is needed to establish graphite calorimeters as primary standards of absorbed dose in these beams. It is governed by the water-to-graphite mass collision stopping power ratio and fluence correction factors, which depend on the particle fluence distributions in each of the two media. The paper focuses on the experimental and numerical determination of this fluence correction factor for an 80 MeV/A carbon ion beam. Measurements have been performed in the nuclear physics laboratory INFN-LNS in Catania (Sicily, Italy). The numerical simulations have been made with a Geant4 Monte Carlo code through the GATE simulation platform. The experimental data are in good agreement with the simulated results for the fluence correction factors and are found to be close to unity. The experimental values increase with depth reaching 1.010 before the Bragg peak region. They have been determined with an uncertainty of 0.25%. Different numerical results are obtained depending on the level of approximation made in calculating the fluence correction factors. When considering carbon ions only, the difference between measured and calculated values is maximal just before the Bragg peak, but its value is less than 1.005. The numerical value is close to unity at the surface and increases to 1.005 near the Bragg peak. When the fluence of all charged particles is considered, the fluence correction factors are lower than unity at the surface and increase with depth up to 1.025 before the Bragg peak. Besides carbon ions, secondary particles created due to nuclear interactions have to be included in the analysis: boron ions ((10)B and (11)B), beryllium ions ((7)Be), alpha particles and protons. At the conclusion of this work, we have the conversion of dose-to-graphite to dose-to-water to apply to the response of a graphite

  8. Measurements of conversion factor of the Argonauta reactor

    International Nuclear Information System (INIS)

    Souza, M.I.S.

    1988-01-01

    The conversion factor (Fc) in the Argonauta reactor using uranium target prepared by electrodeposition method, irradiated in the core and in thermal collumn with thermal neutrons flux maximum is studied. Some data obtained through γ radiation emited by U-239 are shown. (M.J.C.) [pt

  9. Is G a conversion factor or a fundamental unit?

    OpenAIRE

    Fiorentini, G.; Okun, L.; Vysotsky, M.

    2001-01-01

    By using fundamental units c, h, G as conversion factors one can easily transform the dimensions of all observables. In particular one can make them all ``geometrical'', or dimensionless. However this has no impact on the fact that there are three fundamental units, G being one of them. Only experiment can tell us whether G is basically fundamental.

  10. SU-D-209-06: Study On the Dose Conversion Coefficients in Pediatric Radiography with the Development of Children Voxel Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Q [Institute of Radiation Medicine Fudan University, Shanghai (China); Shanghai General Hospital, Shanghai, Shanghai (China); Zhuo, W; Liu, H [Institute of Radiation Medicine Fudan University, Shanghai (China); Liu, Y; Chen, T [Shanghai General Hospital, Shanghai, Shanghai (China)

    2016-06-15

    Purpose: Conversion coefficients of organ dose normalized to entrance skin dose (ESD) are widely used to evaluate the organ doses directly using ESD without time-consuming dose measurement, this work aims to investigate the dose conversion coefficients in pediatric chest and abdomen radiography with the development of 5 years and 10 years old children voxel phantoms. Methods: After segmentation of organs and tissues from CT slice images of ATOM tissue-equivalent phantoms, a 5-year-old and a 10-year-old children computational voxel phantoms were developed for Monte Carlo simulation. The organ doses and the entrance skin dose for pediatric chest postero-anterior projection and abdominal antero-posterior projection were simulated at the same time, and then the organ dose conversion coefficients were calculated.To verify the simulated results, dose measurement was carried out with ATOM tissue-equivalent phantoms for 5 year chest radiography. Results: Simulated results and experimental results matched very well with each other, the result differences of all the organs covered in radiation field were below 16% for 5-year-old child in chest projection. I showed that the conversion coefficients of organs covered in the radiation field were much larger than organs out of the field for all the study cases, for example, the conversion coefficients of stomach, liver intestines, and pancreas are larger for abdomen radiography while conversion coefficients of lungs are larger for chest radiography. Conclusion: The voxel children phantoms were helpful to evaluate the radiation doses more accurately and efficiently. Radiation field was the essential factor that affects the organ dose, use reasonably small field should be encouraged for radiation protection. This work was supported by the National Natural Science Foundation of China(11475047)

  11. SU-D-209-06: Study On the Dose Conversion Coefficients in Pediatric Radiography with the Development of Children Voxel Phantoms

    International Nuclear Information System (INIS)

    Liu, Q; Zhuo, W; Liu, H; Liu, Y; Chen, T

    2016-01-01

    Purpose: Conversion coefficients of organ dose normalized to entrance skin dose (ESD) are widely used to evaluate the organ doses directly using ESD without time-consuming dose measurement, this work aims to investigate the dose conversion coefficients in pediatric chest and abdomen radiography with the development of 5 years and 10 years old children voxel phantoms. Methods: After segmentation of organs and tissues from CT slice images of ATOM tissue-equivalent phantoms, a 5-year-old and a 10-year-old children computational voxel phantoms were developed for Monte Carlo simulation. The organ doses and the entrance skin dose for pediatric chest postero-anterior projection and abdominal antero-posterior projection were simulated at the same time, and then the organ dose conversion coefficients were calculated.To verify the simulated results, dose measurement was carried out with ATOM tissue-equivalent phantoms for 5 year chest radiography. Results: Simulated results and experimental results matched very well with each other, the result differences of all the organs covered in radiation field were below 16% for 5-year-old child in chest projection. I showed that the conversion coefficients of organs covered in the radiation field were much larger than organs out of the field for all the study cases, for example, the conversion coefficients of stomach, liver intestines, and pancreas are larger for abdomen radiography while conversion coefficients of lungs are larger for chest radiography. Conclusion: The voxel children phantoms were helpful to evaluate the radiation doses more accurately and efficiently. Radiation field was the essential factor that affects the organ dose, use reasonably small field should be encouraged for radiation protection. This work was supported by the National Natural Science Foundation of China(11475047)

  12. Applicability of dose conversion coefficients of ICRP 74 to Asian adult males: Monte Carlo simulation study

    International Nuclear Information System (INIS)

    Lee, Choonsik; Lee, Choonik; Lee, Jai-Ki

    2007-01-01

    International Commission on Radiological Protection (ICRP) reported comprehensive dose conversion coefficients for adult population, which is exposed to external photon sources in the Publication 74. However, those quantities were calculated from so-called stylized (or mathematical) phantoms composed of simplified mathematical surface equations so that the discrepancy between the phantoms and real human anatomy has been investigated by several authors using Caucasian-based voxel phantoms. To address anatomical and racial limitations of the stylized phantoms, several Asian-based voxel phantoms have been developed by Korean and Japanese investigators, independently. In the current study, photon dose conversion coefficients of ICRP 74 were compared with those from a total of five Asian-based male voxel phantoms, whose body dimensions were almost identical. Those of representative radio-sensitive organs (testes, red bone marrow, colon, lungs, and stomach), and effective dose conversion coefficients were obtained for comparison. Even though organ doses for testes, colon and lungs, and effective doses from ICRP 74 agreed well with those from Asian voxel phantoms within 10%, absorbed doses for red bone marrow and stomach showed significant discrepancies up to 30% which was mainly attributed to difference of phantom description between stylized and voxel phantoms. This study showed that the ICRP 74 dosimetry data, which have been reported to be unrealistic compared to those from Caucasian-based voxel phantoms, are also not appropriate for Asian population

  13. Calculation of age-dependent dose conversion coefficients for radionuclides uniformly distributed in air

    International Nuclear Information System (INIS)

    Hung, Tran Van; Satoh, Daiki; Takahashi, Fumiaki; Tsuda, Shuichi; Endo, Akira; Saito, Kimiaki; Yamaguchi, Yasuhiro

    2005-02-01

    Age-dependent dose conversion coefficients for external exposure to photons emitted by radionuclides uniformly distributed in air were calculated. The size of the source region in the calculation was assumed to be effectively semi-infinite in extent. Firstly, organ doses were calculated with a series of age-specific MIRD-5 type phantoms using MCNP code, a Monte Carlo transport code. The calculations were performed for mono-energetic photon sources of twelve energies from 10 keV to 5 MeV and for phantoms of newborn, 1, 5, 10 and 15 years, and adult. Then, the effective doses to the different age-phantoms from the mono-energetic photon sources were estimated based on the obtained organ doses. The calculated effective doses were used to interpolate the conversion coefficients of the effective doses for 160 radionuclides, which are important for dose assessment of nuclear facilities. In the calculation, energies and intensities of emitted photons from radionuclides were taken from DECDC, a recent compilation of decay data for radiation dosimetry developed at JAERI. The results are tabulated in the form of effective dose per unit concentration and time (Sv per Bq s m -3 ). (author)

  14. Laparascopic cholecystectomy for acute cholecystitis: Can preoperative factors predict conversion?

    International Nuclear Information System (INIS)

    Khan, Iftikhar A.; El-Tinay, Omer E.

    2004-01-01

    To determine if preoperative clinical, laboratory and radiology data can predict conversion of laparascopic cholecystectomy for acute cholecystitis to open procedure. Retrospective analysis of 44 laparascopic cholecystectomies were performed for acute cholecystitisbetween August 2000 and July 2002 at King Khalid University Hospital, Riyadh, kingdom of Saudi Arabia. Data related to age and sex of patients, maximum body temprature,white blood cell count, gallbladder wall thickness or ultrasonography and timing of surgery from onset of symptoms were collected.The procedure was converted from laparascopic to open cholecystectomy in 10 patients (23%). Conversion rate was significantly high (33% versus zero; p=0.01) if the gallbladder wall was thickened. Conversion rate was significantly low ( Zero versus 32%: p=0.01) if the procedure was performed within 48 hours from the onset of the symptoms. The data relawted to age, sex, white blood cell count and body temprature did not reliably predict conversion of laparascopic cholecystectomy (LD) for acute cholecystitis to open procedure. There was no mortality or major morbidity. Laparascopic cholecystectomy is a safe modality of treatment for acute cholecystitis. Factors associated with increased conversion rate are thickened gallbladder wall on ultrasonographyand delay in surgery for more than 48 hours from the onset of symptoms. (author)

  15. Effective dose conversion coefficients for X-ray radiographs of the chest and the abdomen

    Energy Technology Data Exchange (ETDEWEB)

    Lima, F.R.A. [Centro regional de Ciencias Nucleares, CRCN/CNEN, Rua Conego Barata, 999, Tamarineira, Recife, PE (Brazil); Kramer, R.; Vieira, J.W.; Khoury, H.J. [Departamento de Energia Nuclear, DEN/UFPE, Cidade Universitaria, Recife, PE (Brazil)]. E-mail: falima@cnen.gov.br

    2004-07-01

    The recently developed MAX (Male Adult voXel) and the FAXht (Female Adult voXel) head and trunk phantoms have been used to calculate organ and tissue equivalent dose conversion coefficients for X-ray radiographs of the chest and the abdomen as a function of source and field parameters, like voltage, filtration, field size, focus-to-skin distance, etc. Based on the equivalent doses to twenty three organs and tissues at risk, the effective dose has been determined and compared with corresponding data for others phantoms. The influence of different radiation transport codes, different tissue compositions and different human anatomies have been investigated separately. (Author)

  16. Effective dose conversion coefficients for X-ray radiographs of the chest and the abdomen

    International Nuclear Information System (INIS)

    Lima, F.R.A.; Kramer, R.; Vieira, J.W.; Khoury, H.J.

    2004-01-01

    The recently developed MAX (Male Adult voXel) and the FAXht (Female Adult voXel) head and trunk phantoms have been used to calculate organ and tissue equivalent dose conversion coefficients for X-ray radiographs of the chest and the abdomen as a function of source and field parameters, like voltage, filtration, field size, focus-to-skin distance, etc. Based on the equivalent doses to twenty three organs and tissues at risk, the effective dose has been determined and compared with corresponding data for others phantoms. The influence of different radiation transport codes, different tissue compositions and different human anatomies have been investigated separately. (Author)

  17. Gallbladder Nonvisualization in Cholecystectomy: A Factor for Conversion.

    Science.gov (United States)

    Slack, Daniel R; Grisby, Shaunda; Dike, Uzoamaka Kimberly; Kohli, Harjeet

    2018-01-01

    Many risk factors have been identified in minimally invasive cholecystectomies that lead to higher complications and conversion rates. No study that we encountered looked at nonvisualization of the gallbladder (GB) during surgery as a risk factor. We hypothesized that nonvisualization was associated with an increased risk of complications and could be an early intraoperative identifier of a higher risk procedure. Recognizing this could allow surgeons to be aware of potential risks and to be more likely to convert to open for the safety of the patient. We looked at minimally invasive cholecystectomies performed at our institution from January 2015 through April 2016 and had the performing resident fill out a survey after the surgery. Outcomes were conversion rates, intraoperative complications, and blood loss and were analyzed via Pearson χ 2 test or Mann-Whitney U test. The primary outcome showed a conversion rate of 37% in nonvisualized GBs versus 0% in visualized ( P = .001). Secondary outcomes showed significant differences in GB perforations (74% vs 13%, P = .001), omental vessel bleeding (16% vs. 0%, P = .005), and EBL (46 mL vs 29 mL, P = .001). Intraoperative nonvisualization of the GB after adequate positioning caused significantly increased risk of intraoperative complications and conversion. This knowledge could be useful during intraoperative assessment, to decide whether a case should be continued as a minimally invasive procedure or converted early to help reduce risk to the patient. Further randomized controlled studies should be performed to further demonstrate the value of this assessment.

  18. Measurement of secondary cosmic radiation and calculation of associated dose conversion coefficients for humans

    International Nuclear Information System (INIS)

    Simmer, Gregor

    2012-01-01

    Due to secondary cosmic radiation (SCR), pilots and flight attendants receive elevated effective doses at flight altitudes. For this reason, since 2003 aircrew members are considered as occupationally exposed, in Germany. This work deals with the calculation of dose conversion coefficients (DCC) for protons, neutrons, electrons, positrons, photons and myons, which are crucial for estimation of effective dose from SCR. For the first time, calculations were performed combining Geant4 - a Monte Carlo code developed at CERN - with the voxel phantoms for the reference female and male published in 2008 by ICRP and ICRU. Furthermore, measurements of neutron fluence spectra - which contribute the major part to the effective dose of SCR - were carried out at the Environmental Research Station Schneefernerhaus (UFS) located at 2650 m above sea level nearby the Zugspitze mountain, Germany. These measured neutron spectra, and additionally available calculated spectra, were then folded with the DCC calculated in this work, and effective dose rates for different heights were calculated.

  19. Monetary conversion factors for economic evaluations of substance use disorders.

    Science.gov (United States)

    McCollister, Kathryn; Yang, Xuan; Sayed, Bisma; French, Michael T; Leff, Jared A; Schackman, Bruce R

    2017-10-01

    Estimating the economic consequences of substance use disorders (SUDs) is important for evaluating existing programs and new interventions. Policy makers in particular must weigh program effectiveness with scalability and sustainability considerations in deciding which programs to fund with limited resources. This study provides a comprehensive list of monetary conversion factors for a broad range of consequences, services, and outcomes, which can be used in economic evaluations of SUD interventions (primarily in the United States), including common co-occurring conditions such as HCV and HIV. Economic measures were selected from standardized clinical assessment instruments that are used in randomized clinical trials and other research studies (e.g., quasi-experimental community-based projects) to evaluate the impact of SUD interventions. National datasets were also reviewed for additional SUD-related consequences, services, and outcomes. Monetary conversion factors were identified through a comprehensive literature review of published articles as well as targeted searches of other sources such as government reports. Eight service/consequence/outcome domains were identified containing more than sixty monetizable measures of medical and behavioral health services, laboratory services, SUD treatment, social services, productivity outcomes, disability outcomes, criminal activity and criminal justice services, and infectious diseases consequences. Unit-specific monetary conversion factors are reported, along with upper and lower bound estimates, whenever possible. Having an updated and standardized source of monetary conversion factors will facilitate and improve future economic evaluations of interventions targeting SUDs and other risky behaviors. This exercise should be repeated periodically as new sources of data become available to maintain the timeliness, comprehensiveness, and quality of these estimates. Copyright © 2017 The Authors. Published by Elsevier Inc

  20. American National Standard: neutron and gamma-ray flux-to-dose rate factors

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    This Standard presents data recommended for computing biological dose rates due to neutron and gamma-ray radiation fields. Neutron flux-to-dose-rate conversion factors for energies from 2.5 x 10 -8 to 20 MeV are given; the energy range for the gamma-ray conversion factors is 0.01 to 15 MeV. Specifically, this Standard is intended for use by shield designers to calculate wholebody dose rates to radiation workers and the general public. Establishing dose-rate limits is outside the scope of this Standard. Use of this Standard in cases where the dose equivalents are far in excess of occupational exposure guidelines is not recommended

  1. Development of Landscape Dose Factors for dose assessments in SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Rodolfo; Ekstroem, Per-Anders [Facilia AB, Bromma (Sweden); Kautsky, Ulrik [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2006-08-15

    In previous safety assessments Ecosystem Dose Factors (EDFs), were derived from estimates of doses to the most exposed group resulting from constant unit radionuclide release rates over 10,000 years to various ecosystem types, e.g. mires, agricultural lands, lakes and marine ecosystems. A number of limitations of the EDF approach have been identified. The objectives of this report is to further develop the EDF approach, in order to resolve the identified limitations, and to use the improved approach for deriving Dose Conversion Factors for use in the SR-Can risk assessments. The Dose Conversion Factors derived in this report are named Landscape Dose Factors (LDFs). It involves modelling the fate of the radionuclides in the whole landscape, which develops from a sea to a inland situation during 20,000 years. Both candidate sites studies in SR-Can, Forsmark and Laxemar, are included in the study. As a basis for the modelling, the period starting at the beginning of the last interglacial (8,000 BC) is used, over which releases from a hypothetical repository were assumed to take place. For the present temperate period, the overall development of the biosphere at each site is outlined in a 1,000 year perspective and beyond, essentially based on the ongoing shoreline displacement and the understanding on the impact this has on the biosphere. The past development, i.e. from deglaciation to the present time, is inferred from geological records and associated reconstructions of the shore-line. For each time step of 1,000 years, the landscape at the site is described as a number of interconnected biosphere objects constituting an integrated landscape model of each site. The water fluxes through the objects were estimated from the average run-off at the site, the areas of the objects and their associated catchment areas. Radionuclides in both dissolved and particulate forms were considered in the transport calculations. The transformation between ecosystems was modelled as

  2. Determination of conversion factors and efficiency for GM detectors used in measurements of surface pollution

    International Nuclear Information System (INIS)

    Ayala G, J.; Alvarez R, J.T.

    1999-01-01

    One of the objectives of the Radiation protection, is to observe with the National and as International standardization referring to the ICRP dose limitation system (ICRP 26, ICRP 60). In this work it was treated the problem corresponding about how to determine the conversion factor of cpm/mR/h and the absolute efficiency ε, for a Geiger-Muller equipment with thin window. This equipment is used for the beta particle detection. Thus the correct use of calibration factors and the procedures to convert cpm in Bq is expedited and also to apply the ISO procedure for to evaluate contaminated surfaces. (Author)

  3. Fluence to Dose Equivalent Conversion Coefficients for Evaluation of Accelerator Radiation Environments

    International Nuclear Information System (INIS)

    Thomas, Ralph H.; Zeman, Gary H.

    2001-01-01

    The derivation of a set of conversion functions for the expression of neutron fluence measurements in terms of Effective Dose, E, is described. Four functions in analytical form are presented, covering the neutron energy range from 2.5 10-8 to 10+4 MeV, for the interpretation of fluence measurements in the typical irradiation conditions experienced around high-energy proton accelerators such as the Bevatron. For neutron energies below 200 MeV the analytical functions were modeled after the ISO and ROT conversion coefficients in ICRU 57. For neutron energies above 200 MeV, the analytical function was derived from an analysis of recent published data. Sample calculations using either the analytical expressions or the tabulated conversion coefficients from which the analytical expressions are derived show agreement to better than plus/minus 5%

  4. Dose conversion coefficients based on the Chinese mathematical phantom and MCNP code for external photon irradiation

    International Nuclear Information System (INIS)

    Qiu, R.; Li, J.; Zhang, Z.; Liu, L.; Bi, L.; Ren, L.

    2009-01-01

    A set of conversion coefficients from kerma free-in-air to the organ-absorbed dose are presented for external monoenergetic photon beams from 10 keV to 10 MeV based on the Chinese mathematical phantom, a whole-body mathematical phantom model. The model was developed based on the methods of the Oak Ridge National Laboratory mathematical phantom series and data from the Chinese Reference Man and the Reference Asian Man. This work is carried out to obtain the conversion coefficients based on this model, which represents the characteristics of the Chinese population, as the anatomical parameters of the Chinese are different from those of Caucasians. Monte Carlo simulation with MCNP code is carried out to calculate the organ dose conversion coefficients. Before the calculation, the effects from the physics model and tally type are investigated, considering both the calculation efficiency and precision. In the calculation irradiation conditions include anterior-posterior, posterior-anterior, right lateral, left lateral, rotational and isotropic geometries. Conversion coefficients from this study are compared with those recommended in the Publication 74 of International Commission on Radiological Protection (ICRP74) since both the sets of data are calculated with mathematical phantoms. Overall, consistency between the two sets of data is observed and the difference for more than 60% of the data is below 10%. However, significant deviations are also found, mainly for the superficial organs (up to 65.9%) and bone surface (up to 66%). The big difference of the dose conversion coefficients for the superficial organs at high photon energy could be ascribed to kerma approximation for the data in ICRP74. Both anatomical variations between races and the calculation method contribute to the difference of the data for bone surface. (authors)

  5. Dose conversion coefficients based on the Chinese mathematical phantom and MCNP code for external photon irradiation.

    Science.gov (United States)

    Qiu, Rui; Li, Junli; Zhang, Zhan; Liu, Liye; Bi, Lei; Ren, Li

    2009-02-01

    A set of conversion coefficients from kerma free-in-air to the organ-absorbed dose are presented for external monoenergetic photon beams from 10 keV to 10 MeV based on the Chinese mathematical phantom, a whole-body mathematical phantom model. The model was developed based on the methods of the Oak Ridge National Laboratory mathematical phantom series and data from the Chinese Reference Man and the Reference Asian Man. This work is carried out to obtain the conversion coefficients based on this model, which represents the characteristics of the Chinese population, as the anatomical parameters of the Chinese are different from those of Caucasians. Monte Carlo simulation with MCNP code is carried out to calculate the organ dose conversion coefficients. Before the calculation, the effects from the physics model and tally type are investigated, considering both the calculation efficiency and precision. In the calculation irradiation conditions include anterior-posterior, posterior-anterior, right lateral, left lateral, rotational and isotropic geometries. Conversion coefficients from this study are compared with those recommended in the Publication 74 of International Commission on Radiological Protection (ICRP74) since both the sets of data are calculated with mathematical phantoms. Overall, consistency between the two sets of data is observed and the difference for more than 60% of the data is below 10%. However, significant deviations are also found, mainly for the superficial organs (up to 65.9%) and bone surface (up to 66%). The big difference of the dose conversion coefficients for the superficial organs at high photon energy could be ascribed to kerma approximation for the data in ICRP74. Both anatomical variations between races and the calculation method contribute to the difference of the data for bone surface.

  6. Monte Carlo Method in the calculate of conversion coefficients for dose in children's organs and tissues subjected to dentistric radiography

    International Nuclear Information System (INIS)

    Loureiro, E.C.M.; Khoury, H.; Lima, F.R.A.

    1998-01-01

    The increasing utilization of oral X-rays, specially in youngsters and children, prompts the assessment of equivalent doses in their organs and tissues. With this purpose, Monte Carlo code was adopted to simulate an X-ray source irradiating phantoms of the MIRD-5 type with different ages (10, 15 and 40 years old) to calculate the conversion coefficients which transform the exposure at skin to equivalent doses at several organs and tissues of interest. In order to check the computer program, simulations were performed for adult patients using the original code (ADAM,FOR developed by GSF Germany) and the adapted program (MCDRO,PAS). Good agreement between results obtained by both programs was observed. Applications to incisive, canine and molar teeth were simulated. The conversion factors were calculated for the following organs and tissues: thyroid, active bone marrow (head and whole body), bone (facial skeleton, cranium and whole body), skin (head and whole body) and crystalline. Based on the obtained results, it follows that the younger the patient and the langer the field area, the higher the doses in assessed organs and tissues

  7. Determination of the conversion coefficient for ambient dose equivalent, H(10), from air kerma measurements

    International Nuclear Information System (INIS)

    Gonzalez J, F.; Alvarez R, J. T.

    2015-09-01

    Namely the operational magnitudes can be determined by the product of a conversion coefficient by exposure air kerma or fluence, etc. In particular in Mexico for the first time is determined the conversion coefficient (Cc) for operational magnitude Environmental Dose Equivalent H(10) by thermoluminescence dosimetry (TLD) technique. First 30 TLD-100 dosimeters are calibrated in terms of air kerma, then these dosimeters are irradiated inside a sphere ICRU type of PMMA and with the aid of theory cavity the absorbed dose in PMMA is determined at a depth of 10 mm within the sphere D PMMA (10), subsequently absorbed dose to ICRU tissue is corrected and the dose equivalent H(10) is determined. The Cc is determined as the ratio of H(10)/K a obtaining a value of 1.20 Sv Gy -1 with a u c = 3.66%, this being consistent with the published value in ISO-4037-3 of 1.20 Sv Gy -1 with a u c = 2%. (Author)

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

    Directory of Open Access Journals (Sweden)

    Sedigheh Sina

    2015-07-01

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

  9. 76 FR 55213 - Technical Amendments to Federal Employees' Retirement System; Present Value Conversion Factors...

    Science.gov (United States)

    2011-09-07

    ... Employees' Retirement System; Present Value Conversion Factors for Spouses of Deceased Separated Employees... to read as follows: Appendix A to Subpart C of Part 843--Present Value Conversion Factors for Earlier...

  10. Direct measurement of electron beam quality conversion factors using water calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Renaud, James, E-mail: james.renaud@mail.mcgill.ca; Seuntjens, Jan [Medical Physics Unit, McGill University, Montréal, Québec H3G 1A4 (Canada); Sarfehnia, Arman [Medical Physics Unit, McGill University, Montréal, Québec H3G 1A4, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3E2 (Canada); Marchant, Kristin [Allan Blair Cancer Centre, Saskatchewan Cancer Agency, Regina, Saskatchewan S4T 7T1, Canada and Department of Oncology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A1 (Canada); McEwen, Malcolm; Ross, Carl [Ionizing Radiation Standards, National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada)

    2015-11-15

    Purpose: In this work, the authors describe an electron sealed water calorimeter (ESWcal) designed to directly measure absorbed dose to water in clinical electron beams and its use to derive electron beam quality conversion factors for two ionization chamber types. Methods: A functioning calorimeter prototype was constructed in-house and used to obtain reproducible measurements in clinical accelerator-based 6, 9, 12, 16, and 20 MeV electron beams. Corrections for the radiation field perturbation due to the presence of the glass calorimeter vessel were calculated using Monte Carlo (MC) simulations. The conductive heat transfer due to dose gradients and nonwater materials was also accounted for using a commercial finite element method software package. Results: The relative combined standard uncertainty on the ESWcal dose was estimated to be 0.50% for the 9–20 MeV beams and 1.00% for the 6 MeV beam, demonstrating that the development of a water calorimeter-based standard for electron beams over such a wide range of clinically relevant energies is feasible. The largest contributor to the uncertainty was the positioning (Type A, 0.10%–0.40%) and its influence on the perturbation correction (Type B, 0.10%–0.60%). As a preliminary validation, measurements performed with the ESWcal in a 6 MV photon beam were directly compared to results derived from the National Research Council of Canada (NRC) photon beam standard water calorimeter. These two independent devices were shown to agree well within the 0.43% combined relative uncertainty of the ESWcal for this beam type and quality. Absorbed dose electron beam quality conversion factors were measured using the ESWcal for the Exradin A12 and PTW Roos ionization chambers. The photon-electron conversion factor, k{sub ecal}, for the A12 was also experimentally determined. Nonstatistically significant differences of up to 0.7% were found when compared to the calculation-based factors listed in the AAPM’s TG-51 protocol

  11. Direct measurement of electron beam quality conversion factors using water calorimetry.

    Science.gov (United States)

    Renaud, James; Sarfehnia, Arman; Marchant, Kristin; McEwen, Malcolm; Ross, Carl; Seuntjens, Jan

    2015-11-01

    In this work, the authors describe an electron sealed water calorimeter (ESWcal) designed to directly measure absorbed dose to water in clinical electron beams and its use to derive electron beam quality conversion factors for two ionization chamber types. A functioning calorimeter prototype was constructed in-house and used to obtain reproducible measurements in clinical accelerator-based 6, 9, 12, 16, and 20 MeV electron beams. Corrections for the radiation field perturbation due to the presence of the glass calorimeter vessel were calculated using Monte Carlo (MC) simulations. The conductive heat transfer due to dose gradients and nonwater materials was also accounted for using a commercial finite element method software package. The relative combined standard uncertainty on the ESWcal dose was estimated to be 0.50% for the 9-20 MeV beams and 1.00% for the 6 MeV beam, demonstrating that the development of a water calorimeter-based standard for electron beams over such a wide range of clinically relevant energies is feasible. The largest contributor to the uncertainty was the positioning (Type A, 0.10%-0.40%) and its influence on the perturbation correction (Type B, 0.10%-0.60%). As a preliminary validation, measurements performed with the ESWcal in a 6 MV photon beam were directly compared to results derived from the National Research Council of Canada (NRC) photon beam standard water calorimeter. These two independent devices were shown to agree well within the 0.43% combined relative uncertainty of the ESWcal for this beam type and quality. Absorbed dose electron beam quality conversion factors were measured using the ESWcal for the Exradin A12 and PTW Roos ionization chambers. The photon-electron conversion factor, kecal, for the A12 was also experimentally determined. Nonstatistically significant differences of up to 0.7% were found when compared to the calculation-based factors listed in the AAPM's TG-51 protocol. General agreement between the relative

  12. Conversion coefficients for determination of dispersed photon dose during radiotherapy: NRUrad input code for MCNP.

    Science.gov (United States)

    Shahmohammadi Beni, Mehrdad; Ng, C Y P; Krstic, D; Nikezic, D; Yu, K N

    2017-01-01

    Radiotherapy is a common cancer treatment module, where a certain amount of dose will be delivered to the targeted organ. This is achieved usually by photons generated by linear accelerator units. However, radiation scattering within the patient's body and the surrounding environment will lead to dose dispersion to healthy tissues which are not targets of the primary radiation. Determination of the dispersed dose would be important for assessing the risk and biological consequences in different organs or tissues. In the present work, the concept of conversion coefficient (F) of the dispersed dose was developed, in which F = (Dd/Dt), where Dd was the dispersed dose in a non-targeted tissue and Dt is the absorbed dose in the targeted tissue. To quantify Dd and Dt, a comprehensive model was developed using the Monte Carlo N-Particle (MCNP) package to simulate the linear accelerator head, the human phantom, the treatment couch and the radiotherapy treatment room. The present work also demonstrated the feasibility and power of parallel computing through the use of the Message Passing Interface (MPI) version of MCNP5.

  13. CTC-ask: a new algorithm for conversion of CT numbers to tissue parameters for Monte Carlo dose calculations applying DICOM RS knowledge

    International Nuclear Information System (INIS)

    Ottosson, Rickard O; Behrens, Claus F

    2011-01-01

    One of the building blocks in Monte Carlo (MC) treatment planning is to convert patient CT data to MC compatible phantoms, consisting of density and media matrices. The resulting dose distribution is highly influenced by the accuracy of the conversion. Two major contributing factors are precise conversion of CT number to density and proper differentiation between air and lung. Existing tools do not address this issue specifically. Moreover, their density conversion may depend on the number of media used. Differentiation between air and lung is an important task in MC treatment planning and misassignment may lead to local dose errors on the order of 10%. A novel algorithm, CTC-ask, is presented in this study. It enables locally confined constraints for the media assignment and is independent of the number of media used for the conversion of CT number to density. MC compatible phantoms were generated for two clinical cases using a CT-conversion scheme implemented in both CTC-ask and the DICOM-RT toolbox. Full MC dose calculation was subsequently conducted and the resulting dose distributions were compared. The DICOM-RT toolbox inaccurately assigned lung in 9.9% and 12.2% of the voxels located outside of the lungs for the two cases studied, respectively. This was completely avoided by CTC-ask. CTC-ask is able to reduce anatomically irrational media assignment. The CTC-ask source code can be made available upon request to the authors. (note)

  14. Methane conversion factors from cattle manure in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Avalos, E E:mail: egavalos@imp.mx [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Ruiz-Suarez, L G [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2007-01-15

    Methane emission factors from different cattle manure management systems including simulated slurry system fermentation were experimentally determined in this and a previous study (Gonzalez-Avalos and Ruiz-Suarez, 2001). Combining results from both studies, we report values for maximum CH4 yield, called B0, for manure produced by cattle under different production systems and climates, which also implies different quality of feeds and associated methane conversion factors (MCF) for distinct manure management systems. This set of data has the same functionality than that of the current IPCC methodology, but offer a wider set of key parameters to estimate methane emissions from manure, which may be of interest in other countries. In this work, we report MCF can be up to 17.3 times smaller than those suggested in the 1996 Revised IPCC Methodology Guidelines (IPCC, 1997) and Good Practice Guidance (IPCC, 2000). [Spanish] Los factores de emision de metano de diferentes sistemas de manejo de excretas, incluyendo la simulacion de la fermentacion en un sistema de lechada, fueron determinados experimentalmente en este trabajo y en otro anterior (Gonzalez-Avalos y Ruiz-Suarez, 2001). Al combinar ambos, se obtuvieron valores para la produccion maxima de metano (B0) provenientes de excretas producidas por ganado bovino de diferentes sistemas de produccion y climas, lo cual implica diversas calidades de alimento y factores de conversion de metano (MCF) dependiendo de los sistemas de manejo de excretas. Este conjunto de datos tiene la misma funcionalidad que los de la metodologia actual del IPCC, pero ofrece un conjunto de parametros mas amplio para estimar las emisiones de metano por excretas, lo cual puede ser de interes en otros paises. En este trabajo se reporta que los MCF pueden ser hasta 17.3 veces mas pequenos que los sugeridos en las Directrices de la Metodologia Revisada del IPCC de 1996 (IPCC, 1997) y en la Guia de Buenas Practicas (IPCC, 2000).

  15. Foetal dose conversion coefficients for ICRP-compliant pregnant models from idealised proton exposures

    International Nuclear Information System (INIS)

    Taranenko, V.; Xu, X. G.

    2009-01-01

    Protection of pregnant women and their foetus against external proton irradiations poses a unique challenge. Assessment of foetal dose due to external protons in galactic cosmic rays and as secondaries generated in aircraft walls is especially important during high-altitude flights. This paper reports a set of fluence to absorbed dose conversion coefficients for the foetus and its brain for external monoenergetic proton beams of six standard configurations (the antero-posterior, the postero-anterior, the right lateral, the left lateral, the rotational and the isotropic). The pregnant female anatomical definitions at each of the three gestational periods (3, 6 and 9 months) are based on newly developed RPI-P series of models whose organ masses were matched within 1% with the International Commission on Radiological Protection reference values. Proton interactions and the transport of secondary particles were carefully simulated using the Monte Carlo N-Particle extended code (MCNPX) and the phantoms consisting of several million voxels at 3 mm resolution. When choosing the physics models in the MCNPX, it was found that the advanced Cascade-Exciton intranuclear cascade model showed a maximum of 9% foetal dose increase compared with the default model combination at intermediate energies below 5 GeV. Foetal dose results from this study are tabulated and compared with previously published data that were based on simplified anatomy. The comparison showed a strong dependence upon the source geometry, energy and gestation period: The dose differences are typically less than 20% for all sources except ISO where systematically 40-80% of higher doses were observed. Below 200 MeV, a larger discrepancy in dose was found due to the Bragg peak shift caused by different anatomy. The tabulated foetal doses represent the latest and most detailed study to date offering a useful set of data to improve radiation protection dosimetry against external protons. (authors)

  16. Calculation of neutron fluence to dose equivalent conversion coefficients using GEANT4

    International Nuclear Information System (INIS)

    Ribeiro, Rosane M.; Santos, Denison de S.; Queiroz Filho, Pedro P. de; Mauricio, CLaudia L.P.; Silva, Livia K. da; Pessanha, Paula R.

    2014-01-01

    Fluence to dose equivalent conversion coefficients provide the basis for the calculation of area and personal monitors. Recently, the ICRP has started a revision of these coefficients, including new Monte Carlo codes for benchmarking. So far, little information is available about neutron transport below 10 MeV in tissue-equivalent (TE) material performed with Monte Carlo GEANT4 code. The objective of this work is to calculate neutron fluence to personal dose equivalent conversion coefficients, H p (10)/Φ, with GEANT4 code. The incidence of monoenergetic neutrons was simulated as an expanded and aligned field, with energies ranging between thermal neutrons to 10 MeV on the ICRU slab of dimension 30 x 30 x 15 cm 3 , composed of 76.2% of oxygen, 10.1% of hydrogen, 11.1% of carbon and 2.6% of nitrogen. For all incident energy, a cylindrical sensitive volume is placed at a depth of 10 mm, in the largest surface of the slab (30 x 30 cm 2 ). Physic process are included for neutrons, photons and charged particles, and calculations are made for neutrons and secondary particles which reach the sensitive volume. Results obtained are thus compared with values published in ICRP 74. Neutron fluence in the sensitive volume was calculated for benchmarking. The Monte Carlo GEANT4 code was found to be appropriate to calculate neutron doses at energies below 10 MeV correctly. (author)

  17. Deuterons at energies of 10 MeV to 1 TeV: Conversion coefficients for fluence-to-absorbed dose, equivalent dose, effective dose and gray equivalent, calculated using Monte Carlo radiation transport code MCNPX 2.7.C

    International Nuclear Information System (INIS)

    Copeland, K.; Parker, D. E.; Friedberg, W.

    2011-01-01

    Conversion coefficients were calculated for fluence-to-absorbed dose, fluence-to-equivalent dose, fluence-to-effective dose and fluence-to-gray equivalent for isotropic exposure of an adult female and an adult male to deuterons ( 2 H + ) in the energy range 10 MeV -1 TeV (0.01-1000 GeV). Coefficients were calculated using the Monte Carlo transport code MCNPX 2.7.C and BodyBuilder TM 1.3 anthropomorphic phantoms. Phantoms were modified to allow calculation of the effective dose to a Reference Person using tissues and tissue weighting factors from 1990 and 2007 recommendations of the International Commission on Radiological Protection (ICRP) and gray equivalent to selected tissues as recommended by the National Council on Radiation Protection and Measurements. Coefficients for the equivalent and effective dose incorporated a radiation weighting factor of 2. At 15 of 19 energies for which coefficients for the effective dose were calculated, coefficients based on ICRP 1990 and 2007 recommendations differed by < 3 %. The greatest difference, 47 %, occurred at 30 MeV. (authors)

  18. Internal and external dose conversion coefficient for domestic reference animals and plant

    Energy Technology Data Exchange (ETDEWEB)

    Keum, Dong Kwon; Jun, In; Lim, Kwang Muk; Park, Du Won; Choi, Young Ho

    2009-07-15

    This report presents the internal and external dose conversion coefficients for domestic reference animals and plant, which are essential to assess the radiological impact of an environmental radiation on non-human species. To calculate the dose conversion coefficients, a uniform isotropic model and a Monte Carlo method for a photon transport simulation in environmental media with different densities have been applied for aquatic and terrestrial animals, respectively. In the modeling all the target animals are defined as a simple 3D elliptical shape. To specify the external radiation source it is assumed that aquatic animals are fully immersed in infinite and uniformly contaminated water, and the on-soil animals are living on the surface of a horizontally infinite soil source, and the in-soil organisms are living at the center of a horizontally infinite and uniformly contaminated soil to a depth of 50cm. A set of internal and external dose conversion coefficients for 8 Korean reference animals and plant (rat, roe-deer, frog, snake, Chinese minnow, bee, earthworm, and pine tree) are presented for 25 radionuclides ({sup 3}H, {sup 7}Be, {sup 14}C, {sup 40}K, {sup 51}Cr, {sup 54}Mn, {sup 59}Fe, {sup 58}Co, {sup 60}Co, {sup 65}Zn, {sup 90}Sr, {sup 95}Zr, {sup 95}Nb, {sup 99}Tc, {sup 106}Ru, {sup 129}I, {sup 131}I, {sup 136}Cs, {sup 137}Cs, {sup 140}Ba, {sup 140}La, {sup 144}Ce, {sup 238}U, {sup 239}Pu, and {sup 240}Pu)

  19. The Generalized Conversion Factor in Einstein's Mass-Energy Equation

    Directory of Open Access Journals (Sweden)

    Ajay Sharma

    2008-07-01

    Full Text Available Einstein's September 1905 paper is origin of light energy-mass inter conversion equation ($L = Delta mc^{2}$ and Einstein speculated $E = Delta mc^{2}$ from it by simply replacing $L$ by $E$. From its critical analysis it follows that $L = Delta mc^{2}$ is only true under special or ideal conditions. Under general cases the result is $L propto Delta mc^{2}$ ($E propto Delta mc^{2}$. Consequently an alternate equation $Delta E = A ub c^{2}Delta M$ has been suggested, which implies that energy emitted on annihilation of mass can be equal, less and more than predicted by $Delta E = Delta mc^{2}$. The total kinetic energy of fission fragments of U-235 or Pu-239 is found experimentally 20-60 MeV less than Q-value predicted by $Delta mc^{2}$. The mass of particle Ds (2317 discovered at SLAC, is more than current estimates. In many reactions including chemical reactions $E = Delta mc^{2}$ is not confirmed yet, but regarded as true. It implies the conversion factor than $c^{2}$ is possible. These phenomena can be explained with help of generalized mass-energy equation $Delta E = A ub c^{2}Delta M$.

  20. CRPS: A contingent hypothesis with prostaglandins as crucial conversion factor.

    Science.gov (United States)

    van der Veen, Phe

    2015-11-01

    CRPS is an acute pain disease expressed as chronic pain with a severe loss of tissue and function. CRPS usually occurs after minor injuries and then progresses in a way that is scarcely controllable, or completely uncontrollable. This article addresses the functional control mechanism of a biological organism, a comparison of techniques, and the way the negative feedback mechanisms fail in regulated feedback systems. The measurement and regulation system is controlled at the local, regional, and central levels in a biological system. Locally generated substances such as prostaglandins and hormones, as well as the central nervous system, play important roles in this process. Prostaglandins fulfil many conversion functions and are involved in vasoactive processes, pain, and inflammation. They play an intermediating role between the activity of the autonomic nervous system and local occurrences. The insufficiently explored conversion function of prostaglandins as a ubiquitously present cofactor may be related to the development of CRPS at sites which have had minor injuries in the past. Chronic Regional Pain Syndrome (CRPS) is a moderately prevalent disease, which occurs more frequently with age. Even though there are diseases known to have a precipitating effect on the aetiology of CRPS, for example Carpal tunnel syndrome, the mechanism of onset is unknown. The disease falls under the category of chronic pain, and seldom has an effective treatment based on scientific research. The economic and psychosocial aspects of the disease are substantial. CRPS is the final position of a positive feedback measurement and control system. Homoeostasis is directed by measurement and control processes. In electronics, a rapid conversion system, which quickly adapts to changing circumstances, superimposed with a delayed conversion system, which ensures a stable basis of homoeostasis. Measured changes are compensatorily controlled. An analogy is expected for a Complex Adaptive System

  1. Correlation of bupivacaine 0.5% dose and conversion from spinal anesthesia to general anesthesia in cesarean sections

    NARCIS (Netherlands)

    Seljogi, D; Wolff, A P; Scheffer, G J; van Geffen, G J; Bruhn, J

    2016-01-01

    BACKGROUND: Failed spinal anesthesia for cesarean sections may require conversion to general anesthesia. The aim of this study was to determine whether the administered spinal bupivacaine dose for performing a cesarean section under spinal anesthesia was related to the conversion rate to general

  2. Conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation 1948--1951

    International Nuclear Information System (INIS)

    Denham, D.H.; Mart, E.I.; Thiede, M.E.

    1993-09-01

    This report is a part of the Hanford Environmental Dose Reconstruction (HEDR) Project, whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the US Department of Energy's (DOE) Hanford Site near Richland, Washington. The key radionuclide emitted that would affect the radiation dose was iodine-131 (Napier 1992). Because the early methods of measuring iodine-131 were not comparable to later techniques, conversion and correction factors are needed to convert the historical measurement data into concentration values that would be determined using today's knowledge and technologies. This report describes the conversion and correction factors developed for reconstructing historical measurements of iodine-131 in Hanford-area vegetation, which was collected from 1948 through the end of December 1951

  3. Conversion factors: SI metric and U.S. customary units

    Science.gov (United States)

    ,

    1977-01-01

    The policy of the U.S. Geological Survey is to foster use of the International System of Units (SI) which was defined by the 11th General Conference of Weights and Measures in 1960. This modernized metric system constitutes an international "language" by means of which communications throughout the world's scientific and economic communities may be improved. This publication is designed to familiarize the reader with the SI units of measurement that correspond to the common units frequently used in programs of the Geological Survey. In the near future, SI units will be used exclusively in most publications of the Survey; the conversion factors provided herein will help readers to obtain a "feel" for each unit and to "think metric."

  4. Recommendations on dose buildup factors used in models for calculating gamma doses for a plume

    International Nuclear Information System (INIS)

    Hedemann Jensen, P.; Thykier-Nielsen, S.

    1980-09-01

    Calculations of external γ-doses from radioactivity released to the atmosphere have been made using different dose buildup factor formulas. Some of the dose buildup factor formulas are used by the Nordic countries in their respective γ-dose models. A comparison of calculated γ-doses using these dose buildup factors shows that the γ-doses can be significantly dependent on the buildup factor formula used in the calculation. Increasing differences occur for increasing plume height, crosswind distance, and atmospheric stability and also for decreasing downwind distance. It is concluded that the most accurate γ-dose can be calculated by use of Capo's polynomial buildup factor formula. Capo-coefficients have been calculated and shown in this report for γ-energies below the original lower limit given by Capo. (author)

  5. Conversion factors for estimating release rate of gaseous radioactivity by an aerial survey

    International Nuclear Information System (INIS)

    Saito, Kimiaki; Moriuchi, Shigeru

    1988-02-01

    Conversion factors necessary for estimating release rate of gaseous radioactivity by an aerial survey are presented. The conversion factors were determined based on calculation assuming a Gaussian plume model as a function of atmospheric stability, down-wind distance and flight height. First, the conversion factors for plumes emitting mono-energy gamma rays were calculated, then, conversion factors were constructed through convolution for the radionuclides essential in an accident of a nuclear reactor, and for mixtures of these radionuclides considering elapsed time after shutdown. These conversion factors are shown in figures, and also polynomial expressions of the conversion factors as a function of height have been decided with the least-squares method. A user can easily obtain proper conversion factors from data shown here. (author)

  6. Conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation, 1945--1947

    International Nuclear Information System (INIS)

    Mart, E.I.; Denham, D.H.; Thiede, M.E.

    1993-12-01

    This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project whose goal is to estimate the radiation dose that individuals could have received from emissions since 1944 at the U.S. Department of Energy's (DOE) Hanford Site near Richland, Washington. The HEDR Project is conducted by Battelle, Pacific Northwest Laboratories (BNW). One of the radionuclides emitted that would affect the radiation dose was iodine-131. This report describes in detail the reconstructed conversion and correction factors for historical measurements of iodine-131 in Hanford-area vegetation which was collected from the beginning of October 1945 through the end of December 1947

  7. Dose and Dose-Rate Effectiveness Factor (DDREF); Der Dosis- und Dosisleistungs-Effektivitaetsfaktor (DDREF)

    Energy Technology Data Exchange (ETDEWEB)

    Breckow, Joachim [Fachhochschule Giessen-Friedberg, Giessen (Germany). Inst. fuer Medizinische Physik und Strahlenschutz

    2016-08-01

    For practical radiation protection purposes it is supposed that stochastic radiation effects a determined by a proportional dose relation (LNT). Radiobiological and radiation epidemiological studies indicated that in the low dose range a dependence on dose rates might exist. This would trigger an overestimation of radiation risks based on the LNT model. OCRP had recommended a concept to combine all effects in a single factor DDREF (dose and dose-Rate effectiveness factor). There is still too low information on cellular mechanisms of low dose irradiation including possible repair and other processes. The Strahlenschutzkommission cannot identify a sufficient scientific justification for DDREF and recommends an adaption to the actual state of science.

  8. Monte Carlo calculations of electron beam quality conversion factors for several ion chamber types

    Energy Technology Data Exchange (ETDEWEB)

    Muir, B. R., E-mail: Bryan.Muir@nrc-cnrc.gc.ca [Measurement Science and Standards, National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6 (Canada); Rogers, D. W. O., E-mail: drogers@physics.carleton.ca [Carleton Laboratory for Radiotherapy Physics, Physics Department, Carleton University, 1125 ColonelBy Drive, Ottawa, Ontario K1S 5B6 (Canada)

    2014-11-01

    Purpose: To provide a comprehensive investigation of electron beam reference dosimetry using Monte Carlo simulations of the response of 10 plane-parallel and 18 cylindrical ion chamber types. Specific emphasis is placed on the determination of the optimal shift of the chambers’ effective point of measurement (EPOM) and beam quality conversion factors. Methods: The EGSnrc system is used for calculations of the absorbed dose to gas in ion chamber models and the absorbed dose to water as a function of depth in a water phantom on which cobalt-60 and several electron beam source models are incident. The optimal EPOM shifts of the ion chambers are determined by comparing calculations of R{sub 50} converted from I{sub 50} (calculated using ion chamber simulations in phantom) to R{sub 50} calculated using simulations of the absorbed dose to water vs depth in water. Beam quality conversion factors are determined as the calculated ratio of the absorbed dose to water to the absorbed dose to air in the ion chamber at the reference depth in a cobalt-60 beam to that in electron beams. Results: For most plane-parallel chambers, the optimal EPOM shift is inside of the active cavity but different from the shift determined with water-equivalent scaling of the front window of the chamber. These optimal shifts for plane-parallel chambers also reduce the scatter of beam quality conversion factors, k{sub Q}, as a function of R{sub 50}. The optimal shift of cylindrical chambers is found to be less than the 0.5 r{sub cav} recommended by current dosimetry protocols. In most cases, the values of the optimal shift are close to 0.3 r{sub cav}. Values of k{sub ecal} are calculated and compared to those from the TG-51 protocol and differences are explained using accurate individual correction factors for a subset of ion chambers investigated. High-precision fits to beam quality conversion factors normalized to unity in a beam with R{sub 50} = 7.5 cm (k{sub Q}{sup ′}) are provided. These

  9. Evaluation of dose conversion coefficients for external exposure using Taiwanese reference man and woman

    International Nuclear Information System (INIS)

    Chang, S.J.; Hung, S.Y.; Liu, Y.L.; Jiang, S.H.; Wu, J.

    2015-01-01

    Reference man has been widely used for external and internal dose evaluation of radiation protection. The parameters of the mathematical model of organs suggested by the International Commission of Radiological Protection (ICRP) are adopted from the average data of Caucasians. However, the organ masses of Asians are significantly different from the data of Caucasians, leading to potentially dosimetric errors. In this study, a total of 40 volunteers whose heights and weights corresponded to the statistical average of Taiwanese adults were recruited. Magnetic resonance imaging was performed, and T2-weighted images were acquired. The Taiwanese reference man and woman were constructed according to the measured organ masses. The dose conversion coefficients (DCFs) for anterior-posterior (AP), posterior-anterior (PA), right lateral (RLAT) and left lateral (LLAT) irradiation geometries were simulated. For the Taiwanese reference man, the average differences of the DCFs compared with the results of ICRP-74 were 7.6, 5.1 and 11.1 % for 0.1, 1 and 10 MeV photons irradiated in the AP direction. The maximum difference reached 51.7 % for the testes irradiated by 10 MeV photons. The size of the trunk, the volume and the geometric position of organs can cause a significant impact on the DCFs for external exposure of radiation. The constructed Taiwanese reference man and woman can be used in radiation protection to increase the accuracy of dose evaluation for the Taiwanese population. (authors)

  10. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons

    International Nuclear Information System (INIS)

    Almeida, Ivan Pedro Salati de

    1995-08-01

    The evaluation of absorbed dose in the case of external and internal contamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy 109 Cd conversion electrons, working with a 4 π proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin 109 Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  11. Organ dose conversion coefficients for voxel models of the reference male and female from idealized photon exposures

    International Nuclear Information System (INIS)

    Schlattl, H; Zankl, M; Petoussi-Henss, N

    2007-01-01

    A new series of organ equivalent dose conversion coefficients for whole body external photon exposure is presented for a standardized couple of human voxel models, called Rex and Regina. Irradiations from broad parallel beams in antero-posterior, postero-anterior, left- and right-side lateral directions as well as from a 360 deg. rotational source have been performed numerically by the Monte Carlo transport code EGSnrc. Dose conversion coefficients from an isotropically distributed source were computed, too. The voxel models Rex and Regina originating from real patient CT data comply in body and organ dimensions with the currently valid reference values given by the International Commission on Radiological Protection (ICRP) for the average Caucasian man and woman, respectively. While the equivalent dose conversion coefficients of many organs are in quite good agreement with the reference values of ICRP Publication 74, for some organs and certain geometries the discrepancies amount to 30% or more. Differences between the sexes are of the same order with mostly higher dose conversion coefficients in the smaller female model. However, much smaller deviations from the ICRP values are observed for the resulting effective dose conversion coefficients. With the still valid definition for the effective dose (ICRP Publication 60), the greatest change appears in lateral exposures with a decrease in the new models of at most 9%. However, when the modified definition of the effective dose as suggested by an ICRP draft is applied, the largest deviation from the current reference values is obtained in postero-anterior geometry with a reduction of the effective dose conversion coefficient by at most 12%

  12. Organ dose conversion coefficients for voxel models of the reference male and female from idealized photon exposures

    Science.gov (United States)

    Schlattl, H.; Zankl, M.; Petoussi-Henss, N.

    2007-04-01

    A new series of organ equivalent dose conversion coefficients for whole body external photon exposure is presented for a standardized couple of human voxel models, called Rex and Regina. Irradiations from broad parallel beams in antero-posterior, postero-anterior, left- and right-side lateral directions as well as from a 360° rotational source have been performed numerically by the Monte Carlo transport code EGSnrc. Dose conversion coefficients from an isotropically distributed source were computed, too. The voxel models Rex and Regina originating from real patient CT data comply in body and organ dimensions with the currently valid reference values given by the International Commission on Radiological Protection (ICRP) for the average Caucasian man and woman, respectively. While the equivalent dose conversion coefficients of many organs are in quite good agreement with the reference values of ICRP Publication 74, for some organs and certain geometries the discrepancies amount to 30% or more. Differences between the sexes are of the same order with mostly higher dose conversion coefficients in the smaller female model. However, much smaller deviations from the ICRP values are observed for the resulting effective dose conversion coefficients. With the still valid definition for the effective dose (ICRP Publication 60), the greatest change appears in lateral exposures with a decrease in the new models of at most 9%. However, when the modified definition of the effective dose as suggested by an ICRP draft is applied, the largest deviation from the current reference values is obtained in postero-anterior geometry with a reduction of the effective dose conversion coefficient by at most 12%.

  13. Calculating gamma dose factors for hot particle exposures

    International Nuclear Information System (INIS)

    Murphy, P.

    1990-01-01

    For hot particle exposures to the skin, the beta component of radiation delivers the majority of the dose. However, in order to fully demonstrate regulatory compliance, licenses must ordinarily provide reasonable bases for assuming that both the gamma component of the skin dose and the whole body doses are negligible. While beta dose factors are commonly available in the literature, gamma dose factors are not. This paper describes in detail a method by which gamma skin dose factors may be calculated using the Specific Gamma-ray Constant, even if the particle is not located directly on the skin. Two common hot particle exposure geometries are considered: first, a single square centimeter of skin lying at density thickness of 7 mg/cm 2 and then at 1000 mg/cm 2 . A table provides example gamma dose factors for a number of isotopes encountered at power reactors

  14. CALCULATION OF FLUENCE-TO-EFFECTIVE DOSE CONVERSION COEFFICIENTS FOR THE OPERATIONAL QUANTITY PROPOSED BY ICRU RC26.

    Science.gov (United States)

    Endo, Akira

    2017-07-01

    Fluence-to-effective dose conversion coefficients have been calculated for photons, neutrons, electrons, positrons, protons, muons, pions and helium ions for various incident angles of radiations. The aim of this calculation is to provide a set of conversion coefficients to the Report Committee 26 (RC26) of the International Commission on Radiation Units and Measurements (ICRU) for use in defining personal dose equivalent for individual monitoring. The data sets comprise effective dose conversion coefficients for incident angles of radiations from 0° to ±90° in steps of 15° and at ±180°. Conversion coefficients for rotational, isotropic, superior hemisphere semi-isotropic and inferior hemisphere semi-isotropic irradiations are also included. Numerical data of the conversion coefficients are presented as supplementary data. The conversion coefficients are used to define the personal dose equivalent, which is being considered by the ICRU RC26, as the operational quantity for individual monitoring. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Tritons at energies of 10 MeV to 1 TeV: Conversion coefficients for fluence-to-absorbed dose, equivalent dose, effective dose, and gray equivalent, calculated using Monte Carlo radiation transport code MCNPX 2.7.C

    International Nuclear Information System (INIS)

    Copeland, K.; Parker, D. E.; Friedberg, W.

    2010-01-01

    Conversion coefficients were calculated for fluence-to-absorbed dose, fluence-to-equivalent dose, fluence-to-effective dose and fluence-to-gray equivalent for isotropic exposure of an adult female and an adult male to tritons ( 3 H + ) in the energy range of 10 MeV to 1 TeV (0.01-1000 GeV). Coefficients were calculated using Monte Carlo transport code MCNPX 2.7.C and BodyBuilder TM 1.3 anthropomorphic phantoms. Phantoms were modified to allow calculation of effective dose to a Reference Person using tissues and tissue weighting factors from 1990 and 2007 recommendations of the International Commission on Radiological Protection (ICRP) and calculation of gray equivalent to selected tissues as recommended by the National Council on Radiation Protection and Measurements. At 15 of the 19 energies for which coefficients for effective dose were calculated, coefficients based on ICRP 2007 and 1990 recommendations differed by less than 3%. The greatest difference, 43%, occurred at 30 MeV. Published by Oxford Univ. Press on behalf of the US Government 2010. (authors)

  16. Helions at energies of 10 MeV to 1 TeV: Conversion coefficients for fluence-to-absorbed dose, equivalent dose, effective dose and gray equivalent, calculated using Monte Carlo radiation transport code MCNPX 2.7.C

    International Nuclear Information System (INIS)

    Copeland, K.; Parker, D. E.; Friedberg, W.

    2010-01-01

    Conversion coefficients were calculated for fluence-to-absorbed dose, fluence-to-equivalent dose, fluence-to-effective dose and fluence-to-gray equivalent, for isotropic exposure of an adult male and an adult female to helions ( 3 He 2+ ) in the energy range of 10 MeV to 1 TeV (0.01-1000 GeV). Calculations were performed using Monte Carlo transport code MCNPX 2.7.C and BodyBuilder TM 1.3 anthropomorphic phantoms modified to allow calculation of effective dose using tissues and tissue weighting factors from either the 1990 or 2007 recommendations of the International Commission on Radiological Protection (ICRP), and gray equivalent to selected tissues as recommended by the National Council on Radiation Protection and Measurements. At 15 of the 19 energies for which coefficients for effective dose were calculated, coefficients based on ICRP 2007 and 1990 recommendations differed by less than 2%. The greatest difference, 62%, occurred at 100 MeV. Published by Oxford Univ. Press on behalf of the U.S. Government 2010. (authors)

  17. Conversion factors for a mobile survey method by car in the Chernobyl area

    International Nuclear Information System (INIS)

    Sakamoto, R.; Saito, K.

    2003-01-01

    Conversion factors for the purpose of mobile survey by car in the Chernobyl area have been evaluated using simulation calculations. In the calculations, the width of road is assumed as being 4 m, 10 m and 20 m and the surrounding area is divided into ten zones contaminated homogeneously by 137 Cs with different depth profiles in the ground. The air kerma contribution from all zones to the road is simulated. A conversion factor is calculated by dividing the air kerma rate in typical land-use adjacent to the road by that on the road. Conversion factors in various land uses around the roads are examined. The calculated conversion factors agree with the conversion factors measured in the Chernobyl area within an accuracy of 20%. Further, basic data, needed for composing conversion factors appropriate to other contaminated regions with different depth distributions from the Chernobyl area, are also indicated. (author)

  18. Biomass conversion and expansion factors are afected by thinning

    Directory of Open Access Journals (Sweden)

    Teresa Duque Enes

    2014-12-01

    Full Text Available Aim of the study: The objective of this paper is to investigate the use of Biomass Conversion and Expansion Factors (BCEFs in maritime pine (Pinus pinaster Ait. stands subjected to thinning.Area of the study: The study area refers to different ecosystems of maritime pine stands inNorthern Portugal.Material and methods: The study is supported by time data series and cross sectional data collected in permanent plots established in the North of Portugal. An assessment of BCEF values for the aboveground compartments and for total was completed for each studied stand. Identification of key variables affecting the value of the BCEFs in time and with thinning was conducted using correlation analysis. Predictive models for estimation of the BCEFs values in time and after thinning were developed using nonlinear regression analysis.Research highlights: For periods of undisturbed growth, the results show an allometric relationship between the BCEFs, the dominant height and the mean diameter. Management practices such as thinning also influence the factors. Estimates of the ratio change before and after thinning depend on thinning severity and thinning type. The developed models allow estimating the biomass of the stands, for the aboveground compartments and for total, based on information of stand characteristics and of thinning descriptors. These estimates can be used to assess the forest dry wood stocks to be used for pulp, bioenergy or other purposes, as well as the biomass quantification to support the evaluation of the net primary productivity.Keywords: carbon; softwood; thinning; volume; wood energy; maritime pine.

  19. Dose conversion coefficients for neutron exposure to the lens of the human eye

    International Nuclear Information System (INIS)

    Manger, Ryan P.; Bellamy, Michael B.; Eckerman, Keith F.

    2011-01-01

    Dose conversion coefficients for the lens of the human eye have been calculated for neutron exposure at energies from 1 x 10 -9 to 20 MeV and several standard orientations: anterior-to-posterior, rotational and right lateral. MCNPX version 2.6.0, a Monte Carlo-based particle transport package, was used to determine the energy deposited in the lens of the eye. The human eyeball model was updated by partitioning the lens into sensitive and insensitive volumes as the anterior portion (sensitive volume) of the lens being more radiosensitive and prone to cataract formation. The updated eye model was used with the adult UF-ORNL mathematical phantom in the MCNPX transport calculations.

  20. Dose conversion coefficients for neutron exposure to the lens of the human eye

    International Nuclear Information System (INIS)

    Manger, R. P.; Bellamy, M. B.; Eckerman, K. F.

    2012-01-01

    Dose conversion coefficients for the lens of the human eye have been calculated for neutron exposure at energies from 1 x 10 -9 to 20 MeV and several standard orientations: anterior-to-posterior, rotational and right lateral. MCNPX version 2.6.0, a Monte Carlo-based particle transport package, was used to determine the energy deposited in the lens of the eye. The human eyeball model was updated by partitioning the lens into sensitive and insensitive volumes as the anterior portion (sensitive volume) of the lens being more radiosensitive and prone to cataract formation. The updated eye model was used with the adult UF-ORNL mathematical phantom in the MCNPX transport calculations. (authors)

  1. Effective dose in abdominal digital radiography: Patient factor

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Ji Sung; Koo, Hyun Jung; Park, Jung Hoon; Cho, Young Chul; Do, Kyung Hyun [Dept. of Radiology, and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul(Korea, Republic of); Yang, Hyung Jin [Dept. of Medical Physics, Korea University, Seoul (Korea, Republic of)

    2017-08-15

    To identify independent patient factors associated with an increased radiation dose, and to evaluate the effect of patient position on the effective dose in abdominal digital radiography. We retrospectively evaluated the effective dose for abdominal digital radiography in 222 patients. The patients were divided into two groups based on the cut-off dose value of 0.311 mSv (the upper third quartile of dose distribution): group A (n = 166) and group B (n = 56). Through logistic regression, independent factors associated with a larger effective dose were identified. The effect of patient position on the effective dose was evaluated using a paired t-test. High body mass index (BMI) (≥ 23 kg/m2), presence of ascites, and spinal metallic instrumentation were significantly associated with a larger effective dose. Multivariate logistic regression analysis revealed that high BMI [odds ratio (OR), 25.201; p < 0.001] and ascites (OR, 25.132; p < 0.001) were significantly associated with a larger effective dose. The effective dose was significantly lesser (22.6%) in the supine position than in the standing position (p < 0.001). High BMI and ascites were independent factors associated with a larger effective dose in abdominal digital radiography. Significant dose reduction in patients with these factors may be achieved by placing the patient in the supine position during abdominal digital radiography.

  2. Organ dose conversion coefficients based on a voxel mouse model and MCNP code for external photon irradiation.

    Science.gov (United States)

    Zhang, Xiaomin; Xie, Xiangdong; Cheng, Jie; Ning, Jing; Yuan, Yong; Pan, Jie; Yang, Guoshan

    2012-01-01

    A set of conversion coefficients from kerma free-in-air to the organ absorbed dose for external photon beams from 10 keV to 10 MeV are presented based on a newly developed voxel mouse model, for the purpose of radiation effect evaluation. The voxel mouse model was developed from colour images of successive cryosections of a normal nude male mouse, in which 14 organs or tissues were segmented manually and filled with different colours, while each colour was tagged by a specific ID number for implementation of mouse model in Monte Carlo N-particle code (MCNP). Monte Carlo simulation with MCNP was carried out to obtain organ dose conversion coefficients for 22 external monoenergetic photon beams between 10 keV and 10 MeV under five different irradiation geometries conditions (left lateral, right lateral, dorsal-ventral, ventral-dorsal, and isotropic). Organ dose conversion coefficients were presented in tables and compared with the published data based on a rat model to investigate the effect of body size and weight on the organ dose. The calculated and comparison results show that the organ dose conversion coefficients varying the photon energy exhibits similar trend for most organs except for the bone and skin, and the organ dose is sensitive to body size and weight at a photon energy approximately <0.1 MeV.

  3. The knowledge conversion SECI process as innovation indicator analysis factor

    OpenAIRE

    Silva, Elaine da [UNESP; Valentim, Marta Lígia Pomim [UNESP

    2013-01-01

    It highlights the innovation importance in the current society and presents innovation indicators applied in 125 countries. We made an analysis in the 80 variables distributed through seven GII pillars, trying to identify the direct, indirect or null incidences of the knowledge conversion way described by the SECI Process. The researched revealed the fact that knowledge management, in this case specifically the knowledge conversion SECI Process, is present in the variables that, according to ...

  4. Radiation risk factors and dose limits

    International Nuclear Information System (INIS)

    Barendsen, G.W.

    1979-01-01

    The contents of the ICRP publications 9 (1965) and 26 (1977) are outlined and the research conducted during these years considered. Expressions are derived for the frequency for induction of cancer from the most common irradiations - X rays, gamma rays and electrons. The dose limits advised by the ICRP are discussed and the first two fundamental principles are presented - that no one should be subjected to radiation without useful cause and that in those cases where irradiation is thought necessary, the medical, scientific, social and economic advantages need to be carefully considered with respect to the possible disadvantages. (C.F.)

  5. Preoperative risk factors for conversion and learning curve of minimally invasive distal pancreatectomy.

    Science.gov (United States)

    Hua, Yongfei; Javed, Ammar A; Burkhart, Richard A; Makary, Martin A; Weiss, Matthew J; Wolfgang, Christopher L; He, Jin

    2017-11-01

    Although laparoscopic distal pancreatectomy is considered a standard approach, 10% to 40% of these are converted. The preoperative risk factors for conversion are not well described. The aim of this study was to identify risk factors associated with conversion. Clinicopathological variables of 211 consecutive patients who underwent laparoscopic distal pancreatectomy between January 2007 and December 2015 at Johns Hopkins were analyzed to identify factors associated with conversion. Furthermore, the learning curve for laparoscopic distal pancreatectomy was studied. On univariate analysis of diabetes mellitus, preoperative diagnosis of malignant disease, multiorgan resection, surgeons' years and case experience were significantly associated with conversion (all P pancreatectomy with a preoperative diagnosis of malignant disease or possible multiorgan resection are at a higher risk of conversion. Surgeon experience of performing >15 procedures significantly reduces the risk of conversion. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Organ-specific external dose coefficients and protective apron transmission factors for historical dose reconstruction for medical personnel.

    Science.gov (United States)

    Simon, Steven L

    2011-07-01

    While radiation absorbed dose (Gy) to the skin or other organs is sometimes estimated for patients from diagnostic radiologic examinations or therapeutic procedures, rarely is occupationally-received radiation absorbed dose to individual organs/tissues estimated for medical personnel; e.g., radiologic technologists or radiologists. Generally, for medical personnel, equivalent or effective radiation doses are estimated for compliance purposes. In the very few cases when organ doses to medical personnel are reconstructed, the data is usually for the purpose of epidemiologic studies; e.g., a study of historical doses and risks to a cohort of about 110,000 radiologic technologists presently underway at the U.S. National Cancer Institute. While ICRP and ICRU have published organ-specific external dose conversion coefficients (DCCs) (i.e., absorbed dose to organs and tissues per unit air kerma and dose equivalent per unit air kerma), those factors have been published primarily for mono-energetic photons at selected energies. This presents two related problems for historical dose reconstruction, both of which are addressed here. It is necessary to derive conversion factor values for (1) continuous distributions of energy typical of diagnostic medical x-rays (bremsstrahlung radiation), and (2) energies of particular radioisotopes used in medical procedures, neither of which are presented in published tables. For derivation of DCCs for bremsstrahlung radiation, combinations of x-ray tube potentials and filtrations were derived for different time periods based on a review of relevant literature. Three peak tube potentials (70 kV, 80 kV, and 90 kV) with four different amounts of beam filtration were determined to be applicable for historic dose reconstruction. The probabilities of these machine settings were assigned to each of the four time periods (earlier than 1949, 1949-1954, 1955-1968, and after 1968). Continuous functions were fit to each set of discrete values of the

  7. Solar Program Assessment: Environmental Factors - Ocean Thermal Energy Conversion.

    Science.gov (United States)

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    This report presents the environmental problems which may arise with the further development of Ocean Thermal Energy Conversion, one of the eight Federally-funded solar technologies. To provide a background for this environmental analysis, the history and basic concepts of the technology are reviewed, as are its economic and resource requirements.…

  8. Conversion Intentions of Interns: What Are the Motivating Factors?

    Science.gov (United States)

    Hurst, Jessica L.; Good, Linda K.; Gardner, Phil

    2012-01-01

    Purpose: The purpose of this study is to investigate interns' supervisory support expectations, psychological contract obligations, job satisfaction, perception of advancement opportunities and affective organisational commitment in an attempt to gain a better understanding of how these variables influence interns' conversion intentions.…

  9. Influence of the rate of conversion of HT and HTO on projected radiation doses from release of molecular tritium

    International Nuclear Information System (INIS)

    Jacobs, D.G.; Easterly, C.E.; Phillips, J.E.

    1979-01-01

    Releases of tritium in the past have been largely in the form of tritiated water, and the projected radiation doses could be estimated by assuming tritium behaviour to parallel that of water. There is increasing interest in potential releases of tritium in the form of HT because of significant recent advances in fusion reactor research. Several recent studies have shown that bacteria containing the enzyme hydrogenase can catalyse the conversion of HT to HTO at rates several orders of magnitude faster than the rates measured in atmospheric systems. Rates of conversion in the soil have been combined with estimates of rates of permeation of HT into the soil and with global and local models depicting tritium transport and cycling. The results suggest that for the expected conversion rates, the impact on projected radiation doses should be relatively minor. (author)

  10. Ratio of the dose factors of the isotopes of iodine

    International Nuclear Information System (INIS)

    Papadopoulos, D.; Thomas, P.

    1977-12-01

    The ratio of dose factors occurring during inhalation and ingestion to the respective dose factors of I-129 is calculated for the isotopes of I-123 to I-126 and I-129 to I-135. All the dose factors refer to the thyroid as the critical organ. A distinction is made between adults and infants up to 1 year of age. To calculate the ratios only the effective energies and the effective half-lives in the human body and on grass are required. Most of the data have been taken from the literature. The effective energies of I-123 and I-125 have been calculated as examples. (orig.) [de

  11. Dose modification factors in boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Allen, B.J. (Australian Nuclear Science and Technology Organization (ANSTO), Menai (Australia))

    1993-01-01

    The effective treatment depth and therapeutic ratio in boron neutron capture therapy (BNCT) depend on a number of macroscopic dose factors such as boron concentrations in the tumor, normal tissue and blood. However, the role of various microscopic dose modification factors can be of critical importance in the evaluation of normal tissue tolerance levels. An understanding of these factors is valuable in designing BNCT experiments and the selection of appropriate boron compounds. These factors are defined in this paper and applied to the case of brain tumors with particular attention to capillary endothelial cells and oligodendrocytes. (orig.).

  12. Experimental determination of relative light conversion factors of TLD-100 for protons with energies from 2.0 to 9.0 MeV

    International Nuclear Information System (INIS)

    Schmidt, P.; Fellinger, J.; Huebner, K.; Henniger, J.

    1985-01-01

    Relative light conversion factors (RLCF) for heavy charged particles (protons, deuterons, recoils) are needed for the calculation of the neutron sensitivity of thermoluminescent (TL) detectors. Such light conversion factors can be determined experimentally. A method is represented for the experimental determination of RLCF. The described experimental facility gives the possibility of irradiation of different luminophor samples with heavy charged particles and flux determination and particle spectrometry at the same time. For the determination of RLCF the doses are needed which are applicated at the irradiation with heavy charged particles and gamma radiation, respectively, and the according detector readings at the TL evaluation. The problems arising at the dose determination are discussed. With this experimental facility the RLCF for TLD-100 for protons were determined. The relative light conversion factors determined according to the light sum method as well as the peak height method are summarizinhly represented and discussed. Furthermore a comparison of the glow curves is made after gamma and proton irradiation

  13. Investigation of the HU-density conversion method and comparison of dose distribution for dose calculation on MV cone beam CT images

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Joo; Lee, Seu Ran; Suh, Tae Suk [Dept. of Biomedical Engineering, The Catholic University of Korea, Bucheon (Korea, Republic of)

    2011-11-15

    Modern radiation therapy techniques, such as Image-guided radiation therapy (IGRT), Adaptive radiation therapy (ART) has become a routine clinical practice on linear accelerators for the increase the tumor dose conformity and improvement of normal tissue sparing at the same time. For these highly developed techniques, megavoltage cone beam computed tomography (MVCBCT) system produce volumetric images at just one rotation of the x-ray beam source and detector on the bottom of conventional linear accelerator for real-time application of patient condition into treatment planning. MV CBCT image scan be directly registered to a reference CT data set which is usually kilo-voltage fan-beam computed tomography (kVFBCT) on treatment planning system and the registered image scan be used to adjust patient set-up error. However, to use MV CBCT images in radiotherapy, reliable electron density (ED) distribution are required. Patients scattering, beam hardening and softening effect caused by different energy application between kVCT, MV CBCT can cause cupping artifacts in MV CBCT images and distortion of Houns field Unit (HU) to ED conversion. The goal of this study, for reliable application of MV CBCT images into dose calculation, MV CBCT images was modified to correct distortion of HU to ED using the relationship of HU and ED from kV FBCT and MV CBCT images. The HU-density conversion was performed on MV CBCT image set using Dose difference map was showing in Figure 1. Finally, percentage differences above 3% were reduced depending on applying density calibration method. As a result, total error co uld be reduced to under 3%. The present study demonstrates that dose calculation accuracy using MV CBCT image set can be improved my applying HU-density conversion method. The dose calculation and comparison of dose distribution from MV CBCT image set with/without HU-density conversion method was performed. An advantage of this study compared to other approaches is that HU

  14. An observational study evaluating tacrolimus dose, exposure, and medication adherence after conversion from twice- to once-daily tacrolimus in liver and kidney transplant recipients.

    Science.gov (United States)

    Bäckman, Lars; Persson, Carl-Axel

    2014-03-17

    Immunosuppression regimens in transplantation medicine are complex. Drugs with extended release action have simplified medication dosing without affecting efficacy. This prospective, observational, multicenter study, conducted in a routine medical practice setting, evaluated changes in tacrolimus daily dose and trough levels and patient-reported medication adherence at day 90 after 1:1 (mg: mg) conversion to once-daily tacrolimus in adult liver and kidney transplant recipients. Data from 224 recipients of a liver (n=19) or kidney (n=205) transplant, average age 51±14.5 years, were evaluated. The mean change in tacrolimus daily dose was +0.04 mg/day. Dose remained stable after conversion in 62.5%, was lower in 15.6%, and higher in 22% of patients. Trough level after conversion was lower in 62.6% and higher in 36.5%; generally, levels were 12.8% lower than pre-conversion levels. No acute rejection, graft loss, or serious safety events were observed. Two deaths occurred due to myocardial infarction. Conversion helped 19% to less frequently forget medications and 55% reported no difference in remembering to take the once-daily dose after conversion. The change in dosing frequency was identified as "better" for 55%. Tacrolimus daily dose remained stable while trough levels were significantly lower after conversion to once-daily dosing. Safety and efficacy were maintained; reduced dosing frequency had no apparent influence on patient-reported medication adherence.

  15. VizieR Online Data Catalog: Monochromatic conversion factors to LIR & Mdust (Schreiber+, 2018)

    Science.gov (United States)

    Schreiber, C.; Elbaz, D.; Pannella, M.; Wang, T.; Ciesla, L.; Franco, M.

    2017-10-01

    These tables contain conversion factors to translate observed fluxes (Sν) or luminosities (ν*Lν) into total infrared luminosity (LIR) and dust mass (Mdust). The conversion factors are provided for the most commonly used ALMA bands (Band 3 to Band 9) and all JWST MIRI broad bands (F777W to F2550W). These factors are tabulated as a function of redshift. For each conversion factor, the tables also provide the logarithmic uncertainty on the conversion (in dex), which reflects the diversity in spectral shape. These data were calibrated on the deep Spitzer and Herschel observations of the CANDELS fields, as well as early ALMA observations. They are therefore valid for galaxies of masses close to 1010Mȯ and above. (3 data files).

  16. CTC-ask: a new algorithm for conversion of CT numbers to tissue parameters for Monte Carlo dose calculations applying DICOM RS knowledge

    DEFF Research Database (Denmark)

    Ottosson, Rickard; Behrens, Claus F.

    2011-01-01

    One of the building blocks in Monte Carlo (MC) treatment planning is to convert patient CT data to MC compatible phantoms, consisting of density and media matrices. The resulting dose distribution is highly influenced by the accuracy of the conversion. Two major contributing factors are precise c...... outside of the lungs for the two cases studied, respectively. This was completely avoided by CTC-ask. CTC-ask is able to reduce anatomically irrational media assignment. The CTC-ask source code can be made available upon request to the authors....

  17. Effect of Dose Deposition Profile on E Beam Curing Conversion and Physical Properties of Thick Thermosetting Materials

    International Nuclear Information System (INIS)

    Mommer, C.

    2006-01-01

    Ionizing radiation is currently applied in new curing process for composites with thermosetting matrix bearing vinyl moieties and more generally unsaturations. The high single or multiple dose curing progression of thick samples of acrylate functional oligomers has been investigated by means of Raman microscopy. The Raman microscopy technique allows localized and accurate measurements to reveal the depth conversion profiles. Measurements have been performed on samples treated with increasing doses and with the use of different kinds of high energy electron accelerators available on the market. It was shown that the conversion was not equal thru the samples thickness in all cases, leading to gradient properties in the thermosetting materials which can be of a great importance in composite parts applications. The purpose of these observations has been investigated and it points out the importance of the heat dissipation in the advancement of the polymerisation reaction

  18. A systematic study on factors affecting patient dose, (1)

    International Nuclear Information System (INIS)

    Otsuka, Akiyoshi; Higashida, Yoshiharu; Utsumi, Hiromoto; Ota, Masaji; Nakanishi, Takashi

    1979-01-01

    In the study of possible reduction in irradiation dose to patients during medical treatments, the following two methods can be considered: (1) To obtain absorbed doses for each part of a body in diagnostic X-ray examinations. (2) To obtain data on factors such as the tube voltage which may affect patient dose. There are a number of reports both at home and abroad concerning the above (1), but very few reports are available concerning the above (2). Moreover, most of them are on fragmentary aspects of each factor and no systematic reports have been made. For this reason, we have taken up, as factors affecting the patient dose, the field size, the tube voltage, and by checking them again, we wanted to obtain some systematic data. Our aim has been fully attained by conducting an experiment. In the ICRP's Publ. 26 issued last year, the idea of the critical organ which had not been fully elucidated in the Publ. 9 was abandoned. As a result, assessment of the irradiation doses has become more rational and the total risk for an individual was obtained. In Japan, the idea proposed in the Publ. 9 is adopted. Therefore, in this paper, we will raise some questions regarding the assessment of the irradiation doses, pointing out at the same time the rationality of the idea put forward in Publ. 26. (author)

  19. Measurement of dose equivalent with personal dosemeters and instrumentation of radiological protection in the new operative ICRU magnitudes, for external fields of beta radiation. Part III. Determination of the joint of factors of angular conversion for the secondary source pattern Nr. - 86 Of (1850) MBq

    International Nuclear Information System (INIS)

    Alvarez R, J.T.

    1994-02-01

    It determined the assembly of factors of angular conversion T(0;α), for the source secondary pattern of 90 Sr/ 90 Y (1850 MBq) at a distance detecting source of 30 cm, in the following angles: 0, 15, 30, 45, 60 and 75 0 . Obtaining the values of: 1.01, 1.05, 1.13, 1.19 and 0.95, respectively. Their Global uncertainty is smaller to 1.5% for all the cases and its percentage differences with regard to the values reported by the Draft of the norm ISO 6980(1992) they are smaller to 3.0% for all the cases.The technique employee was that of the extrapolation Chamber and the treatment of the uncertainties is made of agreement with the recommendations of the BIPM. (Author)

  20. Hounsfield units variations: impact on CT-density based conversion tables and their effects on dose distribution.

    Science.gov (United States)

    Zurl, B; Tiefling, R; Winkler, P; Kindl, P; Kapp, K S

    2014-01-01

    Determination of dose error margins in radiation therapy planning due to variations in Hounsfield Units (HU) values dependent on the use of different CT scanning protocols. Based on a series of different CT scanning protocols used in clinical practice, conversion tables for radiation dose calculations were generated and subsequently tested on a phantom. These tables were then used to recalculate the radiation therapy plans of 28 real patients after an incorrect scanning protocol had inadvertently been used for these patients. Different CT parameter settings resulted in errors of HU values of up to 2.6% for densities of 1.1 g/cm(3). The largest errors were associated with changes in the tube voltage. Tests on a virtual water phantom with layers of variable thickness and density revealed a sawtooth-shaped curve for the increase of dose differences from 0.3 to 0.6% and 1.5% at layer thicknesses of 1, 3, and 7 cm, respectively. Use of a beam hardening filter resulted in a reference dose difference of 0.6% in response to a density change of 5%. The recalculation of data from 28 patients who received radiation therapy to the head revealed an overdose of 1.3 ± 0.4% to the bone and 0.7 ± 0.1% to brain tissue. On average, therefore, one monitor unit (range 0-3 MU) per 100 MU more than the correct dose had been given. Use of different CT scanning protocols leads to variations of up to 20% in the HU values. This can result in a mean systematic dose error of 1.5%. Specific conversion tables and automatic CT scanning protocol recognition could reduce dose errors of these types.

  1. Factors associated with sputum culture conversion in patients with pulmonary tuberculosis

    Directory of Open Access Journals (Sweden)

    Greta Musteikienė

    Full Text Available Objective: The aim of this study was to determine what factors are associated with sputum culture conversion after 1 month of tuberculosis (TB treatment. Materials and methods: A total of 52 patients with new drug susceptible pulmonary TB were included in the study. Patients completed St. George respiratory questionnaire (SGRQ, they were asked about smoking, alcohol use, living conditions and education. Body mass index (BMI measurements, laboratory tests (C reactive protein [CRP], vitamin D, albumin were performed, and chest X-ray was done. After 1 month of treatment sputum culture was repeated. Results: Culture conversion after 1 month of treatment was found in 38.5% cases. None of investigated social factors appeared to have an effect on conversion, but worse overall health status (as reported in SGRQ and longer duration of tobacco smoking were detected in the “no conversion” group. Concentrations of albumin, CRP, X-ray score and the time it took Mycobacterium tuberculosis culture to grow also differed. Patients who scored 30 or more on SGRQ were more than 7 times as likely to have no conversion. However, the most important factor predicting sputum culture conversion was sputum smear grade at the beginning of treatment: patients with grade of 2+ or more had more than 20-fold higher relative risk for no conversion. Using receiver operating characteristic curve analysis, we also developed a risk score for no conversion. Conclusions: The most important factors in predicting sputum culture conversion after 1 month of treatment were grades of acid-fast bacilli in sputum smears at time of diagnosis and scores of SGRQ. Keywords: Smoking, Smear grade, St. George respiratory questionnaire, Tuberculosis, Culture conversion

  2. Volume correction factor in time dose relationships in brachytherapy

    International Nuclear Information System (INIS)

    Supe, S.J.; Sasane, J.B.

    1987-01-01

    Paterson's clinical data about the maximum tolerance doses for various volumes of interstitial implants with Ra-226 delivered in seven days was made use of in deriving volume correction factors for TDF and CRE concepts respectively for brachytherapy. The derived volume correction factors for TDF and for CRE differ fromthe one assumed for CRE by Kirk et al. and implied for TDF by Goitein. A normalising volume of 70 cc has been suggested for both CRE and TDF concepts for brachytherapy. A table showing the volume corrected TDF is presented for various volumes and dose rates for continuous irradiation. The use of this table is illustrated with examples. (orig.) [de

  3. Dose reduction factors from a radioactive cloud for large buildings

    International Nuclear Information System (INIS)

    Grand, J. le; Roux, Y.

    1986-01-01

    A set of complex and accurate computer codes has been established to determine the transport of photons emitted from a radioactive cloud through various media. The geometrical and physical description of large buildings with various numbers of floors and rooms can be done by the user. The codes can calculate, in any room or apartment, the characteristics of the photon fields (photon flux, energy flux and distribution, direction distribution) and whole-body absorbed dose rates in a phantom standing or lying on the floor. The dose reduction factor is then the quotient of the mean absorbed dose rate in the apartment to the absorbed dose rate in the phantom standing on the ground outdoors. Applications to several modern multistorey buildings are presented. The results show the influence of various parameters such as density and composition of building materials, the fraction of the external building surface containing apertures and initial photon energy. (author)

  4. A systematic study on factors affecting patient dose, 2

    International Nuclear Information System (INIS)

    Otsuka, Akiyoshi; Higashida, Yoshiharu; Utsumi, Hiromoto; Ota, Masaji; Nakanishi, Takashi

    1979-01-01

    In the preceding report, we dealt with the field size and the tube voltage. This paper covers the differences in patient dose due to the focus to film distance (FFD), the patient thickness and whether the grid is used or not. Regarding the FFD, 100 cm is most commonly employed except in X-ray examinations of the chest, but from the viewpoint of the patient dose, this requires special consideration as to whether there is any theoretical basis for it. The patient thickness has a great bearing on the patient dose, but there is an individual difference, and it is almost impossible to change it artificially. However, there has been no detailed report on the relation between the patient thickness and the patient dose, therefore, this report treats of such relationship as well. Concerning the grid, consideration is given to the exposure times (Bucky factor). (author)

  5. Calculation of neutron fluence to dose equivalent conversion coefficients using GEANT4; Calculo de coeficientes de fluencia de neutrons para equivalente de dose individual utilizando o GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Rosane M.; Santos, Denison de S.; Queiroz Filho, Pedro P. de; Mauricio, CLaudia L.P.; Silva, Livia K. da; Pessanha, Paula R., E-mail: rosanemribeiro@oi.com.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    Fluence to dose equivalent conversion coefficients provide the basis for the calculation of area and personal monitors. Recently, the ICRP has started a revision of these coefficients, including new Monte Carlo codes for benchmarking. So far, little information is available about neutron transport below 10 MeV in tissue-equivalent (TE) material performed with Monte Carlo GEANT4 code. The objective of this work is to calculate neutron fluence to personal dose equivalent conversion coefficients, H{sub p} (10)/Φ, with GEANT4 code. The incidence of monoenergetic neutrons was simulated as an expanded and aligned field, with energies ranging between thermal neutrons to 10 MeV on the ICRU slab of dimension 30 x 30 x 15 cm{sup 3}, composed of 76.2% of oxygen, 10.1% of hydrogen, 11.1% of carbon and 2.6% of nitrogen. For all incident energy, a cylindrical sensitive volume is placed at a depth of 10 mm, in the largest surface of the slab (30 x 30 cm{sup 2}). Physic process are included for neutrons, photons and charged particles, and calculations are made for neutrons and secondary particles which reach the sensitive volume. Results obtained are thus compared with values published in ICRP 74. Neutron fluence in the sensitive volume was calculated for benchmarking. The Monte Carlo GEANT4 code was found to be appropriate to calculate neutron doses at energies below 10 MeV correctly. (author)

  6. Monte Carlo calculations of kQ, the beam quality conversion factor

    International Nuclear Information System (INIS)

    Muir, B. R.; Rogers, D. W. O.

    2010-01-01

    Purpose: To use EGSnrc Monte Carlo simulations to directly calculate beam quality conversion factors, k Q , for 32 cylindrical ionization chambers over a range of beam qualities and to quantify the effect of systematic uncertainties on Monte Carlo calculations of k Q . These factors are required to use the TG-51 or TRS-398 clinical dosimetry protocols for calibrating external radiotherapy beams. Methods: Ionization chambers are modeled either from blueprints or manufacturers' user's manuals. The dose-to-air in the chamber is calculated using the EGSnrc user-code egs c hamber using 11 different tabulated clinical photon spectra for the incident beams. The dose to a small volume of water is also calculated in the absence of the chamber at the midpoint of the chamber on its central axis. Using a simple equation, k Q is calculated from these quantities under the assumption that W/e is constant with energy and compared to TG-51 protocol and measured values. Results: Polynomial fits to the Monte Carlo calculated k Q factors as a function of beam quality expressed as %dd(10) x and TPR 10 20 are given for each ionization chamber. Differences are explained between Monte Carlo calculated values and values from the TG-51 protocol or calculated using the computer program used for TG-51 calculations. Systematic uncertainties in calculated k Q values are analyzed and amount to a maximum of one standard deviation uncertainty of 0.99% if one assumes that photon cross-section uncertainties are uncorrelated and 0.63% if they are assumed correlated. The largest components of the uncertainty are the constancy of W/e and the uncertainty in the cross-section for photons in water. Conclusions: It is now possible to calculate k Q directly using Monte Carlo simulations. Monte Carlo calculations for most ionization chambers give results which are comparable to TG-51 values. Discrepancies can be explained using individual Monte Carlo calculations of various correction factors which are more

  7. Proton and photon absorbed-dose conversion coefficients for embryo and foetus from top-down irradiation geometry

    International Nuclear Information System (INIS)

    Chen, J.

    2007-01-01

    Absorbed-dose conversion coefficients are calculated for the embryo of 8 weeks and the foetus of 3, 6 or 9 months when the mother's body is exposed to protons and photons from top-down (TOP) direction. It provides data sets in addition to other standard irradiation geometries published previously. The TOP-irradiation geometry is considered here, because high-energy particles are often peaked from the TOP direction onboard aircraft. The results show that absorbed-doses from high-energy particles could be underestimated significantly if isotropic (ISO) irradiation geometry is assumed. For protons of 100 GeV, absorbed-doses from TOP irradiation are ∼2.3-2.9 times higher than the doses from ISO irradiation for different foetal ages. For 10 GeV photons, foetal doses from TOP irradiation are ∼6.8-12 times higher than the doses from ISO irradiation. The coefficients from TOP-irradiation geometry are given in wide energy ranges, from 100 MeV to 100 GeV for protons and from 50 V to 10 GeV for photons. They can, therefore, be used in various applications whenever exposure from the TOP-irradiation direction is concerned. (authors)

  8. Conversion from laparoscopic to open cholecystectomy: Multivariate analysis of preoperative risk factors

    Directory of Open Access Journals (Sweden)

    Khan M

    2005-01-01

    Full Text Available BACKGROUND: Laparoscopic cholecystectomy has become the gold standard in the treatment of symptomatic cholelithiasis. Some patients require conversion to open surgery and several preoperative variables have been identified as risk factors that are helpful in predicting the probability of conversion. However, there is a need to devise a risk-scoring system based on the identified risk factors to (a predict the risk of conversion preoperatively for selected patients, (b prepare the patient psychologically, (c arrange operating schedules accordingly, and (d minimize the procedure-related cost and help overcome financial constraints, which is a significant problem in developing countries. AIM: This study was aimed to evaluate preoperative risk factors for conversion from laparoscopic to open cholecystectomy in our setting. SETTINGS AND DESIGNS: A case control study of patients who underwent laparoscopic surgery from January 1997 to December 2001 was conducted at the Aga Khan University Hospital, Karachi, Pakistan. MATERIALS AND METHODS: All those patients who were converted to open surgery (n = 73 were enrolled as cases. Two controls who had successful laparoscopic surgery (n = 146 were matched with each case for operating surgeon and closest date of surgery. STATISTICAL ANALYSIS USED: Descriptive statistics were computed and, univariate and multivariate analysis was done through multiple logistic regression. RESULTS: The final multivariate model identified two risk factors for conversion: ultrasonographic signs of inflammation (adjusted odds ratio [aOR] = 8.5; 95% confidence interval [CI]: 3.3, 21.9 and age > 60 years (aOR = 8.1; 95% CI: 2.9, 22.2 after adjusting for physical signs, alkaline phosphatase and BMI levels. CONCLUSION: Preoperative risk factors evaluated by the present study confirm the likelihood of conversion. Recognition of these factors is important for understanding the characteristics of patients at a higher risk of conversion.

  9. Chart of conversion factors: From English to metric system and metric to English system

    Science.gov (United States)

    ,

    1976-01-01

    The conversion factors in the following tables are for conversion of our customary (English) units of measurement to SI*units, and for convenience, reciprocals are shown for converting SI units back to the English system. The first table contains rule-of-thumb figures, useful for "getting the feel" of SI units or mental estimation. The succeeding tables contain factors accurate to 3 or more significant figures. Please refer to known reference volumes for additional accuracy, as well as for factors dealing with other scientific notation involving SI units.

  10. The X CO Conversion Factor from Galactic Multiphase ISM Simulations

    Science.gov (United States)

    Gong, Munan; Ostriker, Eve C.; Kim, Chang-Goo

    2018-05-01

    {CO}(J=1{--}0) line emission is a widely used observational tracer of molecular gas, rendering essential the X CO factor, which is applied to convert CO luminosity to {{{H}}}2 mass. We use numerical simulations to study how X CO depends on numerical resolution, non-steady-state chemistry, physical environment, and observational beam size. Our study employs 3D magnetohydrodynamics (MHD) simulations of galactic disks with solar neighborhood conditions, where star formation and the three-phase interstellar medium (ISM) are self-consistently regulated by gravity and stellar feedback. Synthetic CO maps are obtained by postprocessing the MHD simulations with chemistry and radiation transfer. We find that CO is only an approximate tracer of {{{H}}}2. On parsec scales, W CO is more fundamentally a measure of mass-weighted volume density, rather than {{{H}}}2 column density. Nevertheless, =(0.7{\\textstyle {--}}1.0)× {10}20 {{{cm}}}-2 {{{K}}}-1 {{{km}}}-1 {{s}}, which is consistent with observations and insensitive to the evolutionary ISM state or radiation field strength if steady-state chemistry is assumed. Due to non-steady-state chemistry, younger molecular clouds have slightly lower and flatter profiles of X CO versus extinction than older ones. The {CO}-dark {{{H}}}2 fraction is 26%–79%, anticorrelated with the average extinction. As the observational beam size increases from 1 to 100 pc, increases by a factor of ∼2. Under solar neighborhood conditions, in molecular clouds is converged at a numerical resolution of 2 pc. However, the total CO abundance and luminosity are not converged even at the numerical resolution of 1 pc. Our simulations successfully reproduce the observed variations of X CO on parsec scales, as well as the dependence of X CO on extinction and the CO excitation temperature.

  11. Dose factors to calculate the radiation exposure due to radioactive waste air from nuclear facilities

    International Nuclear Information System (INIS)

    Brenk, H.D.; Vogt, K.J.

    1977-01-01

    An evaluation of the environmental impact of nuclear plants according to paragraph 45 of the Radiation Protection Directive of the Federal Republic of Germany requires the calculation of dose conversion factors indicating the correlation between the contaminated medium and individual radiation exposure. The present study is to be conceived as a contribution to discussion on this subject. For the determination of radiation exposure caused by the waste air of nuclear plants, models are being specified for computing the dose conversion factors for the external exposure pathways of β-submersion, γ-submersion and γ-radiation from contaminated ground as well as the internal exposure pathways of inhalation and ingestion, which further elaborate and improve the models previously applied, especially as far as the ingestion pathway is concerned, which distinguishes between 6 major food categories. The computer models are applied to those radionuclides which are significan for nuclear emitters, in particular nuclear light-water power stations. The results obtained for the individual exposure pathways and affected organs are specified in the form of tables. For this purpose, calculations were first of all carried out for the so-called 'reference man'. The results can be transferred to population groups with different consumption habits (e.g. vegetarians) by the application of correction factors. The models are capable of being extended with a view to covering other age groups. (orig.) [de

  12. Clinical Strategy for Optimal Traditional Chinese Medicine (TCM) Herbal Dose Selection in Disease Therapeutics: Expert Consensus on Classic TCM Herbal Formula Dose Conversion.

    Science.gov (United States)

    Zha, Lin-Hua; He, Li-Sha; Lian, Feng-Mei; Zhen, Zhong; Ji, Hang-Yu; Xu, Li-Peng; Tong, Xiao-Lin

    2015-01-01

    The clinical therapeutics of traditional Chinese medicine (TCM) constitutes a complicated process which involves theory, diagnosis, and formula prescription with specific herbal dosage. Zhang Zhong-Jing's classic work, Treatise on Febrile and Miscellaneous Diseases, has been influencing TCM practice for almost 2000 years. However, during this extended period of time in Chinese history, the Chinese weight measurement system experienced noticeable changes. This change in the weight measurement system inevitably, and perhaps even negatively, affected TCM herbal dosage determination and treatment outcome. Thus, in modern society, a full understanding of the accuracy of herbal dose selection has a critical importance in the TCM daily practice of delivering the best treatment to the patients suffering from different illnesses. In the 973 Project of the Chinese National Basic Research Program, expert consensus on classic TCM formula dose conversion has been reached based on extensive literature review and discussion on the dose-effect relationship of classic TCM formulas. One "liang" in classic TCM formulas is equivalent to 13.8 g. However, based on many TCM basic and clinical studies of variable herbal formula prescriptions and herbal drug preparations, the rule of one liang equals 13.8 g should be adjusted according to different disease conditions. Recommended by the committee on TCM formula dose-effect relationship of the China Association of Chinese Medicine and the World Federation of Chinese Medicine Societies, the following expert consensus has been reached: (i) One liang converts to 6-9 g for the severely and critically ill patients. (ii) One liang converts to 3-6 g for the patients suffering from chronic diseases. (iii) One liang converts to 1-3 g in preventive medicine. The above conversions should be used as a future TCM practice guideline. Using this recommended guideline should enhance the effectiveness of daily TCM practice.

  13. Experimental determination of the angular dependence factor for the dose equivalent for photons in calibration phantoms of PMMA

    International Nuclear Information System (INIS)

    Lund, E.; Carlsson, C.A.; Pernicka, F.

    1994-01-01

    The conversion coefficients from air kerma to dose equivalent at a depth of 10 mm in both a spherical and a slab phantom of PMMA have been determined for the X ray qualities: 40, 80 and 295 kV, ISO 'narrow' spectra; and for 137 Cs γ rays. The angular dependence factors have been experimentally determined for the same qualities and for different angles between 0 o and 180 o . The absorbed doses have been measured with thermoluminescence LiF dosemeters. The conversion coefficients and the angular dependence factors are generally found to agree well with calculated ones. Some minor discrepancies are found for the angular dependence factors and the 30 x 30 x 15 cm 3 PMMA slab phantom. (Author)

  14. Scientific Opinion on the energy conversion factor of D-tagatose for labelling purposes

    DEFF Research Database (Denmark)

    Sjödin, Anders Mikael

    2016-01-01

    Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver a scientific opinion on the energy conversion factor of D-tagatose to be used for calculating the energy value of foods to be declared in nutrition labelling....... Energy conversion factors for nutrients for the purpose of nutrition labelling have been set based on the concept of metabolisable energy (ME). The same methodology has been applied to calculate the energy conversion factor for D-tagatose in this opinion. The assessment is based on a dossier prepared...... for Nutrilab NV and submitted by Bioresco Ltd. At present, data are insufficient to derive an accurate ME value for D-tagatose. Relying on the human data indicating a mean absorption rate of 80% (range 69–88%) and a urinary excretion of either 1% or 5%, the corresponding energy values for D-tagatose would be 2...

  15. Reassessment of NRC's dollar per person-rem conversion factor policy

    International Nuclear Information System (INIS)

    1995-12-01

    The US Nuclear Regulatory Commission (NRC) has completed a review and analysis of its dollar per person-rem conversion factor policy. As a result of this review, the NRC has decided to adopt a $2000 per person-rem conversion factor, subject it to present worth considerations, and limit its scope solely to health effects. This is in contrast to the previous policy and staff practice of using an undiscounted $1000 per person-rem conversion factor that served as a surrogate for all offsite consequences (health and offsite property). The policy shift has been incorporated in ''Regulatory Analysis Guidelines of the US Nuclear Regulatory Commission,'' NUREG/BR-0058, Revision 2, November 1995

  16. Determination of dose factors for external gamma radiation in dwellings

    International Nuclear Information System (INIS)

    Maduar, M.F.; Hiromoto, G.

    2000-01-01

    A significant contribution to the global population exposure to ionizing radiation arises from natural sources, especially from radionuclides present in terrestrial crust. Human activities can eventually increase that exposure to significant levels, from the point of view of radiological protection. The presence of natural radionuclides in building materials may lead to an increment of both external and internal radiation exposure of the population. External exposure in dwellings arises from gamma-emitter radionuclides existing in the walls, floor and ceiling of their rooms. Mathematical models can be used to predict external dose rates inside the room, known the radionuclide concentration activities in dwelling constituents. This paper presents a methodology for theoretical evaluation of external gamma doses due to radionuclides present in the walls of an hypothetical standard room. The room is modeled as three pairs of rectangular sheets with finite thickness. Assessment of doses was performed through the application of photon transport model, taking in account self-absorption and radiation buildup. As the external dose due to a particular radionuclide is proportional to its activity concentration, results are presented as dose factors, defined as a ratio of absorbed dose (nGy.h -1 ) to the activity concentration (Bq.kg -1 ), for each radionuclide. The radionuclides were assumed to be uniformly distributed in the building materials. Calculations were performed for concrete walls and results are presented for 40 K, 226 Ra, and 232 Th, taking in account, for dose calculations, all gamma emitters from 226 Ra and 232 Th decay chains. Sensitivity of the model was estimated by varying four of its input parameters within a reasonable range of applicability, while leaving all other parameters at fixed selected values. The parameters studied and respective ranges of variation were: for thickness, 5 to 60 cm; for density, 0.5 to 4 g.cm -3 ; for the room length, 1.5 to 10 m

  17. The local skin dose conversion coefficients of electrons, protons and alpha particles calculated using the Geant4 code.

    Science.gov (United States)

    Zhang, Bintuan; Dang, Bingrong; Wang, Zhuanzi; Wei, Wei; Li, Wenjian

    2013-10-01

    The skin tissue-equivalent slab reported in the International Commission on Radiological Protection (ICRP) Publication 116 to calculate the localised skin dose conversion coefficients (LSDCCs) was adopted into the Monte Carlo transport code Geant4. The Geant4 code was then utilised for computation of LSDCCs due to a circular parallel beam of monoenergetic electrons, protons and alpha particles electrons and alpha particles are found to be in good agreement with the results using the MCNPX code of ICRP 116 data. The present work thus validates the LSDCC values for both electrons and alpha particles using the Geant4 code.

  18. Dose rate determining factors of PWR primary water

    International Nuclear Information System (INIS)

    Terachi, Takumi; Kuge, Toshiharu; Nakano, Nobuo

    2014-01-01

    The relationship between dose rate trends and water chemistry has been studied to clarify the determining factors on the dose rates. Therefore dose rate trends and water chemistry of 11 PWR plants of KEPCO (Kansai Electric Power Co., Inc.) were summarized. It is indicated that the chemical composition of the oxide film, behaviour of corrosion products and Co-58/Co-60 ratio in the primary system have effected dose rate trends based on plant operation experiences for over 40 years. According to plant operation experiences, the amount of Co-58 has been decreasing with the increasing duration of SG (Steam Generator) usage. It is indicated that the stable oxide film formation on the inner surface of SG tubing, is a major beneficial factor for radiation sources reduction. On the other hand, the reduction of the amount of Co-60 for the long term has been not clearly observed especially in particular high dose plants. The primary water parameters imply that considering release and purification balance on Co-59 is important to prevent accumulation of source term in primary water. In addition, the effect of zinc injection, which relates to the chemical composition of oxide film, was also assessed. As the results, the amount of radioactive Co has been clearly decreased. The decreasing trend seems to correlate to the half-life of Co-60, because it is considered that the injected zinc prevents the uptake of radioactive Co into the oxide film on the inner surface of the components and piping. In this paper, the influence of water chemistry and the replacement experiences of materials on the dose rates were discussed. (author)

  19. Towards a new dose and dose-rate effectiveness factor (DDREF)? Some comments.

    Science.gov (United States)

    Chadwick, K H

    2017-06-26

    The aim of this article is to offer a broader, mechanism-based, analytical tool than that used by (Rühm et al 2016 Ann. ICRP 45 262-79) for the interpretation of cancer induction relationships. The article explains the limitations of this broader analytical tool and the implications of its use in view of the publications by Leuraud et al 2015 (Lancet Haematol. 2 e276-81) and Richardson et al 2015 (Br. Med. J. 351 h5359). The publication by Rühm et al 2016 (Ann. ICRP 45 262-79), which is clearly work in progress, reviews the current status of the dose and dose-rate effectiveness factor (DDREF) as recommended by the ICRP. It also considers the issues which might influence a reassessment of both the value of the DDREF as well as its application in radiological protection. In this article, the problem is approached from a different perspective and starts by commenting on the limited scientific data used by Rühm et al 2016 (Ann. ICRP 45 262-79) to develop their analysis which ultimately leads them to use a linear-quadratic dose effect relationship to fit solid cancer mortality data from the Japanese life span study of atomic bomb survivors. The approach taken here includes more data on the induction of DNA double strand breaks and, using experimental data taken from the literature, directly relates the breaks to cell killing, chromosomal aberrations and somatic mutations. The relationships are expanded to describe the induction of cancer as arising from radiation induced cytological damage coupled to cell killing since the cancer mutated cell has to survive to express its malignant nature. Equations are derived for the induction of cancer after both acute and chronic exposure to sparsely ionising radiation. The equations are fitted to the induction of cancer in mice to illustrate a dose effect relationship over the total dose range. The 'DDREF' derived from the two equations varies with dose and the DDREF concept is called into question. Although the equation for

  20. Factors influencing botulinum toxin dose instability in spasmodic dysphonia patients.

    Science.gov (United States)

    Rosow, David E; Pechman, Amanda; Saint-Victor, Sandra; Lo, Kaming; Lundy, Donna S; Casiano, Roy R

    2015-05-01

    Many patients with spasmodic dysphonia (SD) see consistent effects from botulinum toxin (BTX) injections of the same dose, whereas others require dosage changes over time. We sought to determine whether demographics (age and gender) or environmental factors (smoking) affect the long-term stability of BTX dosing in these patients. Retrospective review. Charts of all patients undergoing BTX injection for adductor SD were reviewed. Dosage change, defined as whether there was any difference in total dosage used between two beneficial injections, was used as a measure of dosing stability. Beneficial injections were indicated by a voice rating score of at least three of four and any non-zero duration of improved voice. Logistic regression analysis was performed to determine whether age, gender, smoking status, or duration of treatment correlated with odds of having a dosage change. A total of 211 patients were ultimately included. Age, gender, and smoking status were all found to have no correlative effect on dosing stability. The only factor that was predictive of dose stability was the number of previous beneficial injections, as every additional injection led to decreased odds of a change in dosage for the next injection (odds ratio=0.964; 95% confidence interval=0.947-0.981). Dosage of BTX injections for long-term treatment of SD has a significant propensity to remain stable over time. Factors such as age, gender, and smoking status do not appear to influence the dosage stability. These findings should allow for better patient counseling regarding expectations for their long-term treatment. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  1. Age-specific effective doses for pediatric MSCT examinations at a large children's hospital using DLP conversion coefficients: a simple estimation method

    International Nuclear Information System (INIS)

    Thomas, Karen E.; Wang, Bo

    2008-01-01

    There is a need for an easily accessible method for effective dose estimation in pediatric CT. To estimate effective doses for a variety of pediatric neurological and body CT examinations in five age groups using recently published age- and region-specific dose length product (DLP) to effective dose conversion coefficients. A retrospective review was performed of 1,431 consecutive CT scans over a 12-week period using age- and weight-adjusted CT protocols. Age- and region-specific DLP to effective dose conversion coefficients were applied to console-displayed DLP data. Effective dose estimates for single-phase head CT scans in neonatal, and 1-, 5-, 10- and 15-year-old age groups were 4.2, 3.6, 2.4, 2.0 and 1.4 mSv, respectively. For abdomen/pelvis CT scans the corresponding effective doses were 13.1, 11.1, 8.4, 8.9 and 5.9 mSv. The range of pediatric CT effective doses is wide, from ultralow dose protocols (<1 mSv) to extended-coverage body examinations (10-15 mSv). Age- and region-specific pediatric DLP to effective dose conversion coefficients provide an accessible and user-friendly method for estimating pediatric CT effective doses that is available to radiologists working without medical physics support. (orig.)

  2. Establishment of detailed eye model of adult chinese male and dose conversion coefficients calculation under neutron exposure

    International Nuclear Information System (INIS)

    Zhu, Hongyu; Qiu, Rui; Ren, Li; Zhang, Hui; Li, Junli; Wu, Zhen; Li, Chunyan

    2017-01-01

    The human eye lens is sensitive to radiation. ICRP-118 publication recommended a reduction of the occupational annual equivalent dose limit from 150 to 20 mSv, averaged over defined periods of 5 y. Therefore, it is very important to build a detailed eye model for the accurate dose assessment and radiation risk evaluation of eye lens. In this work, a detailed eye model was build based on the characteristic anatomic parameters of the Chinese adult male. This eye model includes seven main structures, which are scleral, choroid, lens, iris, cornea, vitreous body and aqueous humor. The lens was divided into sensitive volume and insensitive volume based on different cell populations. The detailed eye model was incorporated into the converted polygon-mesh version of the Chinese reference adult male whole-body surface model. After the incorporation, dose conversion coefficients for the eye lens were calculated for neutron exposure at AP, PA and LAT geometries with Geant4, the neutron energies were from 0.001 eV to 10 MeV. The calculated lens dose coefficients were compared with those of ICRP-116 publication. Significant differences up to 97.47% were found at PA geometry. This could mainly be attributed to the different geometry characteristic of eye model and parameters of head in different phantom between the present work and ICRP-116 publication. (authors)

  3. ESTABLISHMENT OF DETAILED EYE MODEL OF ADULT CHINESE MALE AND DOSE CONVERSION COEFFICIENTS CALCULATION UNDER NEUTRON EXPOSURE.

    Science.gov (United States)

    Zhu, Hongyu; Qiu, Rui; Wu, Zhen; Ren, Li; Li, Chunyan; Zhang, Hui; Li, Junli

    2017-12-01

    The human eye lens is sensitive to radiation. ICRP-118 publication recommended a reduction of the occupational annual equivalent dose limit from 150 to 20 mSv, averaged over defined periods of 5 y. Therefore, it is very important to build a detailed eye model for the accurate dose assessment and radiation risk evaluation of eye lens. In this work, a detailed eye model was build based on the characteristic anatomic parameters of the Chinese adult male. This eye model includes seven main structures, which are scleral, choroid, lens, iris, cornea, vitreous body and aqueous humor. The lens was divided into sensitive volume and insensitive volume based on different cell populations. The detailed eye model was incorporated into the converted polygon-mesh version of the Chinese reference adult male whole-body surface model. After the incorporation, dose conversion coefficients for the eye lens were calculated for neutron exposure at AP, PA and LAT geometries with Geant4, the neutron energies were from 0.001 eV to 10 MeV. The calculated lens dose coefficients were compared with those of ICRP-116 publication. Significant differences up to 97.47% were found at PA geometry. This could mainly be attributed to the different geometry characteristic of eye model and parameters of head in different phantom between the present work and ICRP-116 publication. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Calculation of conversion coefficients for effective dose by using voxel phantoms with defined genus for radiodiagnostic common examinations

    International Nuclear Information System (INIS)

    Lima, F.R.A.; Kramer, R.; Khoury, H.J.; Vieira, J.W.; Loureiro, E.C.M.; Hoff, G.

    2004-01-01

    Patient exposure from radiological examinations is usually quantified in terms of average absorbed dose or equivalent dose to certain radiosensitive organs of the human body. As these quantities cannot be measured in vivo, it is common practice to use physical or computational exposure models, which simulate the exposure to the patient in order to determine not only the quantities of interest (absorbed or equivalent dose), but also at the same time measurable quantities for the exposure conditions given. The ratio between a quantity of interest and a measurable quantity is called a conversion coefficient (CC), which is a function of the source and field parameters (tube voltage, filtration, field size, field position, focus-to-skin distance, etc.), the anatomical properties of the phantom, the elemental composition of relevant body tissues, and the radiation transport method applied. As the effective dose represents a sum over 23 risk-weighted organ and tissue equivalent doses, its determination practically implies the measurement or calculation of a complete distribution of equivalent doses throughout the human body. This task can be resolved most efficiently by means of computational exposure models, which consist of a virtual representation of the human body, also called phantom, connected to a Monte Carlo radiation transport computer code. The recently introduced MAX (Male Adult voXel) and FAXht (Female Adult voXel) head+trunk phantoms have been chosen for this task. With respect to their anatomical properties these phantoms correspond fairly well to the data recommended by the ICRP for the Reference Adult Male and Female. (author)

  5. Assessments of conversion coefficients between equivalent dose and accumulated activity using pre-dose scanning images of patients subjected to radioiodine treatment and the Fax/Egs4 computational model

    International Nuclear Information System (INIS)

    Lopes Filho, Ferdinand de J.; Vieira, Jose W.; Andrade Lima, Fernando R. de

    2008-01-01

    The radioiodine is a technique for treatment of thyroid cancer. In this technique, the patients are submitted to the incorporation of the radioactive substance sodium iodide (Na 131 I), which reacts with physiologically metastasis, thyroid tissue remains of and other organs and tissues of the human body. The locations of these reactions are known as areas of highest concentration, hipercaptured areas, hiperconcentrator areas, 'hot areas' or organ-sources and are viewed through images of nuclear medicine scan known as pre-dose (front and rear). To obtain these images, the patient receives, orally, a quantity of 131 I with low activity (± 74 MBq) and is positioned in the chamber of flicker. According to the attendance of hot areas shown in the images, the doctor determines the nuclear activity to be administered in treatment. This analysis is purely qualitative. In this study, the scanning images of pre-dose were adjusted to the dimensions of FAX voxel phantom, and the hot areas correspond to internal sources of the proposed model. Algorithms were developed to generate particles (photons and electrons) in these regions of the FAX. To estimate the coefficients of conversions between equivalent dose and accumulated activity in major radiosensitive organs, FAX and algorithms source were coupled to the Monte Carlo EGS4 code (Electron Gamma Shower, version 4). With these factors is possible to estimate the equivalent doses in the radiosensitive organs and tissues of patients as long as is know the activity administered and the half-life of organic sources. (author)

  6. Experimental determination of beam quality conversion factors kQ in clinical photon beams using ferrous sulphate (Fricke) dosimetry

    International Nuclear Information System (INIS)

    Palm, A.; Mattsson, Olof

    2002-01-01

    The implementation of protocols based on absorbed dose to water standards requires beam quality conversion factors, k Q . Calculated values of k Q are available for ionization chambers used for reference dosimetry. Ideally, k Q should be experimentally determined at the same beam qualities as that of the user. In this work we measure k Q factors in clinical photon beams and compare them with calculated and measured values. Beam quality conversion factors are determined for clinical photon beams of nominal energies 4 MV, 6 MV, 15 MV, and 25 MV, for commonly used cylindrical ionization chambers. Twelve chambers of eight different types are used. For three of them, no experimental data have previously been available. The experimental procedure is based on measurements with ionization chambers and Fricke dosimetry in the reference beam ( 60 Co γ radiation) and in clinical linear accelerator beams. The k Q values determined in this work generally agree within 0.5% with previously reported experimental values both when %dd(10) x and TPR 20,10 are used for beam quality specification. The agreement with calculated data is generally within 0.5%, except for the 15 MV beam. For this beam the measured values are usually between 0.5% and 1% lower than the data taken from the TG-51 protocol or the TRS-398 code of practice. For three NE2571 chambers and three NE2581 chambers, the maximum observed deviation of individual k Q values is 0.2% and 0.4%, respectively

  7. Influences of external factors on the energy conversion and productivity of Scenedesmus sp. in mass culture

    NARCIS (Netherlands)

    Wesselius, J.C.

    1973-01-01

    Experiments about the influence of external factors on the energy conversion in mass cultures of Scenedesmus are described in this thesis. Several types of culture vessels were used in the laboratory as well as in the open. Demonstration models of Miele washing

  8. 12 CFR 615.5212 - Credit conversion factors-off-balance sheet items.

    Science.gov (United States)

    2010-01-01

    ...). The resultant credit equivalent amount is assigned to the appropriate risk-weight category described... directly or indirectly retains or assumes credit risk. For risk participations in such arrangements... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Credit conversion factors-off-balance sheet...

  9. Application of a conversion factor to estimate the adenoma detection rate from the polyp detection rate.

    LENUS (Irish Health Repository)

    Francis, Dawn L

    2011-03-01

    The adenoma detection rate (ADR) is a quality benchmark for colonoscopy. Many practices find it difficult to determine the ADR because it requires a combination of endoscopic and histologic findings. It may be possible to apply a conversion factor to estimate the ADR from the polyp detection rate (PDR).

  10. Probabilistic quantitative microbial risk assessment model of norovirus from wastewater irrigated vegetables in Ghana using genome copies and fecal indicator ratio conversion for estimating exposure dose.

    Science.gov (United States)

    Owusu-Ansah, Emmanuel de-Graft Johnson; Sampson, Angelina; Amponsah, Samuel K; Abaidoo, Robert C; Dalsgaard, Anders; Hald, Tine

    2017-12-01

    The need to replace the commonly applied fecal indicator conversions ratio (an assumption of 1:10 -5 virus to fecal indicator organism) in Quantitative Microbial Risk Assessment (QMRA) with models based on quantitative data on the virus of interest has gained prominence due to the different physical and environmental factors that might influence the reliability of using indicator organisms in microbial risk assessment. The challenges facing analytical studies on virus enumeration (genome copies or particles) have contributed to the already existing lack of data in QMRA modelling. This study attempts to fit a QMRA model to genome copies of norovirus data. The model estimates the risk of norovirus infection from the intake of vegetables irrigated with wastewater from different sources. The results were compared to the results of a corresponding model using the fecal indicator conversion ratio to estimate the norovirus count. In all scenarios of using different water sources, the application of the fecal indicator conversion ratio underestimated the norovirus disease burden, measured by the Disability Adjusted Life Years (DALYs), when compared to results using the genome copies norovirus data. In some cases the difference was >2 orders of magnitude. All scenarios using genome copies met the 10 -4 DALY per person per year for consumption of vegetables irrigated with wastewater, although these results are considered to be highly conservative risk estimates. The fecal indicator conversion ratio model of stream-water and drain-water sources of wastewater achieved the 10 -6 DALY per person per year threshold, which tends to indicate an underestimation of health risk when compared to using genome copies for estimating the dose. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Measurement of dose equivalent with personal dosemeters and instrumentation of radiological protection in the new operative ICRU magnitudes, for external fields of beta radiation. Part III. Determination of the joint of factors of angular conversion for the secondary source pattern Nr. - 86 Of (1850) MBq; Medicion de dosis equivalente con dosimetros personales e instrumentacion de proteccion radiologica en las nuevas magnitudes operativas ICRU, para campos de radiacion Beta externos. Parte III. Determinacion del conjunto de factores de conversion angular para la fuente patron secundario Nr.- 86 de (1850) MBq

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J.T. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1994-02-15

    It determined the assembly of factors of angular conversion T(0;{alpha}), for the source secondary pattern of {sup 90}Sr/{sup 90}Y (1850 MBq) at a distance detecting source of 30 cm, in the following angles: 0, 15, 30, 45, 60 and 75{sup 0}. Obtaining the values of: 1.01, 1.05, 1.13, 1.19 and 0.95, respectively. Their Global uncertainty is smaller to 1.5% for all the cases and its percentage differences with regard to the values reported by the Draft of the norm ISO 6980(1992) they are smaller to 3.0% for all the cases.The technique employee was that of the extrapolation Chamber and the treatment of the uncertainties is made of agreement with the recommendations of the BIPM. (Author)

  12. Electron beam water calorimetry measurements to obtain beam quality conversion factors.

    Science.gov (United States)

    Muir, Bryan R; Cojocaru, Claudiu D; McEwen, Malcolm R; Ross, Carl K

    2017-10-01

    To provide results of water calorimetry and ion chamber measurements in high-energy electron beams carried out at the National Research Council Canada (NRC). There are three main aspects to this work: (a) investigation of the behavior of ionization chambers in electron beams of different energies with focus on long-term stability, (b) water calorimetry measurements to determine absorbed dose to water in high-energy beams for direct calibration of ion chambers, and (c) using measurements of chamber response relative to reference ion chambers, determination of beam quality conversion factors, k Q , for several ion chamber types. Measurements are made in electron beams with energies between 8 MeV and 22 MeV from the NRC Elekta Precise clinical linear accelerator. Ion chamber measurements are made as a function of depth for cylindrical and plane-parallel ion chambers over a period of five years to investigate the stability of ion chamber response and for indirect calibration. Water calorimetry measurements are made in 18 MeV and 22 MeV beams. An insulated enclosure with fine temperature control is used to maintain a constant temperature (drifts less than 0.1 mK/min) of the calorimeter phantom at 4°C to minimize effects from convection. Two vessels of different designs are used with calibrated thermistor probes to measure radiation induced temperature rise. The vessels are filled with high-purity water and saturated with H 2 or N 2 gas to minimize the effect of radiochemical reactions on the measured temperature rise. A set of secondary standard ion chambers are calibrated directly against the calorimeter. Finally, several other ion chambers are calibrated in the NRC 60 Co reference field and then cross-calibrated against the secondary standard chambers in electron beams to realize k Q factors. The long-term stability of the cylindrical ion chambers in electron beams is better (always <0.15%) than plane-parallel chambers (0.2% to 0.4%). Calorimetry measurements

  13. Calculation of conversion coefficients of dose of a computational anthropomorphic simulator sit exposed to a plane source

    International Nuclear Information System (INIS)

    Santos, William S.; Carvalho Junior, Alberico B. de; Pereira, Ariana J.S.; Santos, Marcos S.; Maia, Ana F.

    2011-01-01

    In this paper conversion coefficients (CCs) of equivalent dose and effective in terms of kerma in the air were calculated suggested by the ICRP 74. These dose coefficients were calculated considering a plane radiation source and monoenergetic for a spectrum of energy varying from 10 keV to 2 MeV. The CCs were obtained for four geometries of irradiation, anterior-posterior, posterior-anterior, lateral right side and lateral left side. It was used the radiation transport code Visual Monte Carlo (VMC), and a anthropomorphic simulator of sit female voxel. The observed differences in the found values for the CCs at the four irradiation sceneries are direct results of the body organs disposition, and the distance of these organs to the irradiation source. The obtained CCs will be used for estimative more precise of dose in situations that the exposed individual be sit, as the normally the CCs available in the literature were calculated by using simulators always lying or on their feet

  14. Risk factors for conversion from unipolar psychotic depression to bipolar disorder.

    Science.gov (United States)

    Østergaard, Søren Dinesen; Straszek, Sune; Petrides, Georgios; Skadhede, Søren; Jensen, Signe Olrik Wallenstein; Munk-Jørgensen, Povl; Nielsen, Jimmi

    2014-03-01

    Patients with unipolar psychotic depression (PD) are at high risk of developing bipolar disorder (BD). This conversion has important implications for the choice of treatment. This study, therefore, aimed to identify risk factors associated with diagnostic conversion from PD to BD. We conducted a population-based, historical prospective cohort study by merging data from Danish registers. Patients assigned an ICD-10 diagnosis of PD between 1 January 1995 and 31 December 2007 were identified in the Danish Central Psychiatric Research Register and were followed until the development of BD, death, loss to follow-up, or 31 December 2007. Potential risk factors for conversion to BD, also defined through various Danish registers, were tested in multiple logistic regression analyses with risk expressed as adjusted odds ratios (AOR). We identified 8,588 patients with PD, of whom 609 (7.1%) developed BD during follow-up. The following characteristics were significantly associated with diagnostic conversion from PD to BD: early onset of PD [AOR = 0.99 (per year of increasing age), p = 0.044], recurrent depression [AOR = 1.02 (per episode), p = 0.036], living alone (AOR = 1.29, p = 0.007), receiving a disability pension (AOR = 1.55, p conversion to BD was prevalent among patients with PD. The following characteristics were significantly associated with this conversion: early onset of PD, recurrent depression, living alone, receiving a disability pension, and the highest educational level being a technical education, short-cycle higher education, or medium-cycle higher education. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Improvement of dose evaluation system for employees at severe accident in a nuclear power plant. Introduction of the dose rate conversion coefficient and addition of the access route edit function

    International Nuclear Information System (INIS)

    Sasaki, Yasuhiro; Minami, Noritoshi; Yoshida, Yoshitaka

    2006-01-01

    Institute of Nuclear Safety System, Inc. had developed the dose evaluation system to evaluate the radiation dose of employees at severe accident in a nuclear power plant. This system has features, which are (1) the dose rate of any evaluation point can be evaluated, (2) the dose rate at any time can be evaluated in consideration of the change in the radioactive source, (3) the dose rate map in the plant can be displayed (4) the dose along the access route when moving can be evaluated, and it is possible to use it for examination of the accident management guideline on the dose side etc.. To upgrade the dose evaluation function of this system, the improvements had been done which were introduction of the dose rate conversion coefficient and addition of the access route edit function. By introducing the dose rate conversion coefficient, the calculation time of the dose rate map in the plant was shortened at about 20 seconds, and a new function to evaluate time-dependent dose rate of any evaluation point was added. By adding the access route edit function, it became possible to re-calculate the dose easily at the route change. (author)

  16. Perforated Peptic Ulcer Repair: Factors Predicting Conversion in Laparoscopy and Postoperative Septic Complications.

    Science.gov (United States)

    Muller, Markus K; Wrann, Simon; Widmer, Jeannette; Klasen, Jennifer; Weber, Markus; Hahnloser, Dieter

    2016-09-01

    The surgical treatment for perforated peptic ulcers can be safely performed laparoscopically. The aim of the study was to define simple predictive factors for conversion and septic complications. This retrospective case-control study analyzed patients treated with either laparoscopic surgery or laparotomy for perforated peptic ulcers. A total of 71 patients were analyzed. Laparoscopically operated patients had a shorter hospital stay (13.7 vs. 15.1 days). In an intention-to-treat analysis, patients with conversion to open surgery (analyzed as subgroup from laparoscopic approach group) showed no prolonged hospital stay (15.3 days) compared to patients with a primary open approach. Complication and mortality rates were not different between the groups. The statistical analysis identified four intraoperative risk factors for conversion: Mannheim peritonitis index (MPI) > 21 (p = 0.02), generalized peritonitis (p = 0.04), adhesions, and perforations located in a region other than the duodenal anterior wall. We found seven predictive factors for septic complications: age >70 (p = 0.02), cardiopulmonary disease (p = 0.04), ASA > 3 (p = 0.002), CRP > 100 (p = 0.005), duration of symptoms >24 h (p = 0.02), MPI > 21(p = 0.008), and generalized peritonitis (p = 0.02). Our data suggest that a primary laparoscopic approach has no disadvantages. Factors necessitating conversions emerged during the procedure inhibiting a preoperative selection. Factors suggesting imminent septic complications can be assessed preoperatively. An assessment of the proposed parameters may help optimize the management of possible septic complications.

  17. Nitrogen-to-Protein Conversion Factors for Crop Residues and Animal Manure Common in China.

    Science.gov (United States)

    Chen, Xueli; Zhao, Guanglu; Zhang, Yang; Han, Lujia; Xiao, Weihua

    2017-10-25

    Accurately determining protein content is essential in exploiting biomass as feed and fuel. A survey of biomass samples in China indicated protein contents from 2.65 to 3.98% for crop residues and from 6.07 to 10.24% for animal manure of dry basis. Conversion factors based on amino acid nitrogen (k A ) ranged from 5.42 to 6.00 for the former and from 4.78 to 5.36 for the latter, indicating that the traditional factor of 6.25 is not suitable for biomass samples. On the other hand, conversion factors from Kjeldahl nitrogen (k P ) ranged from 3.97 to 4.57 and from 2.76 to 4.31 for crop residues and animal manure, respectively. Of note, conversion factors were strongly affected by amino acid composition and levels of nonprotein nitrogen. Thus, k P values of 4.23 for crop residues, 4.11 for livestock manure, and 3.11 for poultry manure are recommended to better estimate protein content from total nitrogen.

  18. Comparing Hp(3) evaluated from the conversion coefficients from air kerma to personal dose equivalent for eye lens dosimetry calibrated on a new cylindrical PMMA phantom

    Science.gov (United States)

    Esor, J.; Sudchai, W.; Monthonwattana, S.; Pungkun, V.; Intang, A.

    2017-06-01

    Based on a new occupational dose limit recommended by ICRP (2011), the annual dose limit for the lens of the eye for workers should be reduced from 150 mSv/y to 20 mSv/y averaged over 5 consecutive years in which no single year exceeding 50 mSv. This new dose limit directly affects radiologists and cardiologists whose work involves high radiation exposure over 20 mSv/y. Eye lens dosimetry (Hp(3)) has become increasingly important and should be evaluated directly based on dosimeters that are worn closely to the eye. Normally, Hp(3) dose algorithm was carried out by the combination of Hp(0.07) and Hp(10) values while dosimeters were calibrated on slab PMMA phantom. Recently, there were three reports from European Union that have shown the conversion coefficients from air kerma to Hp(3). These conversion coefficients carried out by ORAMED, PTB and CEA Saclay projects were performed by using a new cylindrical head phantom. In this study, various delivered doses were calculated using those three conversion coefficients while nanoDot, small OSL dosimeters, were used for Hp(3) measurement. These calibrations were performed with a standard X-ray generator at Secondary Standard Dosimetry Laboratory (SSDL). Delivered doses (Hp(3)) using those three conversion coefficients were compared with Hp(3) from nanoDot measurements. The results showed that percentage differences between delivered doses evaluated from the conversion coefficient of each project and Hp(3) doses evaluated from the nanoDots were found to be not exceeding -11.48 %, -8.85 % and -8.85 % for ORAMED, PTB and CEA Saclay project, respectively.

  19. Monthly Rainfall Erosivity: Conversion Factors for Different Time Resolutions and Regional Assessments

    Directory of Open Access Journals (Sweden)

    Panos Panagos

    2016-03-01

    Full Text Available As a follow up and an advancement of the recently published Rainfall Erosivity Database at European Scale (REDES and the respective mean annual R-factor map, the monthly aspect of rainfall erosivity has been added to REDES. Rainfall erosivity is crucial to be considered at a monthly resolution, for the optimization of land management (seasonal variation of vegetation cover and agricultural support practices as well as natural hazard protection (landslides and flood prediction. We expanded REDES by 140 rainfall stations, thus covering areas where monthly R-factor values were missing (Slovakia, Poland or former data density was not satisfactory (Austria, France, and Spain. The different time resolutions (from 5 to 60 min of high temporal data require a conversion of monthly R-factor based on a pool of stations with available data at all time resolutions. Because the conversion factors show smaller monthly variability in winter (January: 1.54 than in summer (August: 2.13, applying conversion factors on a monthly basis is suggested. The estimated monthly conversion factors allow transferring the R-factor to the desired time resolution at a European scale. The June to September period contributes to 53% of the annual rainfall erosivity in Europe, with different spatial and temporal patterns depending on the region. The study also investigated the heterogeneous seasonal patterns in different regions of Europe: on average, the Northern and Central European countries exhibit the largest R-factor values in summer, while the Southern European countries do so from October to January. In almost all countries (excluding Ireland, United Kingdom and North France, the seasonal variability of rainfall erosivity is high. Very few areas (mainly located in Spain and France show the largest from February to April. The average monthly erosivity density is very large in August (1.67 and July (1.63, while very small in January and February (0.37. This study addresses

  20. A conversion method of air-kerma from the primary, scatter and leakage radiations to ambient dose equivalent for calculating the mamography x-ray shielding barrier

    International Nuclear Information System (INIS)

    Kharrati, H.

    2005-01-01

    The primary, scatter, and leakage doses(in Gy), which constitute the data base for calculating shielding requirements for x-ray facilities, are often converted to the equivalent dose (in sievert) by using a constant of conversion of 1.145Sv/Gy. This constant is used for diagnostic radiology as well as for mammography spectra, and is derived by considering an exposure of 1 R corresponds to an air kerma of 8.73 m Gy, which renders by tradition an equivalent dose of 10 mSv. However, this conversion does not take into account the energy dependence of the conversion coefficients relating air kerma to the equivalent dose as described in ICRU report. Moreover, current radiation protection standards propose the use of the quantity ambient dose equivalent in order to qualify the efficiently of given radiation shielding. Therefore, in this study, a new approach has been introduced for derivation ambient dose equivalent from air kerma to calculate shielding requirements in mammography facilities. This new approach has been used to compute the conversion coefficients relating air kerma to ambient dose equivalent for mammography reference beam series of the Netherlands Metrology Institute Van Swinden Laboratorium (NMi), National Institute of Standards and Technology (NIST), and International Atomic Energy Agency (AIEA) laboratories. The calculation has been performed by the means of two methods which show a maximum deviation less than 10%2 for the primary, scatter, and leakage radiations. The results show that the conversion coefficients vary from 0.242 Sv/ Gy to 0.692 Sv/Gy with an average value of 0.436 Sv/Gy for the primary and the scatter radiations, and form 0.156 Sv/Gy to 1.329 Sv/Gy with an average value of 0.98 Sv/Gy for the leakage radiation. Simpkin et al. using an empirical approach propose a conversion value of 0.50 Sv/Gy for the mammography x-ray spectra. This value approximately coincides with the average conversion value of 0.436 Sv/Gy obtained in this work for

  1. Radiation dose to the thyroid due to incorporation of iodine isotopes: Age dependence and reliability of dose factors

    International Nuclear Information System (INIS)

    Henrichs, K.; Mueller-Brunecker, G.; Paretzke, H.G.

    1983-08-01

    This is the first time that dose factors are published in the literature, together with an assessment of their reliability with regard to the quantification of the dose received by the population in the Federal Republic of Germany due to incorporation if iodine isotopes, taking into account the given age distribution among the population. The calculation of dose factors is based on the latest dosimetric and metabolic models issued by the ICRP (ICRP-30), and the impact of the various parameters and their variability on the accuracy of dose factor determination is assessed. The procedure followed to calculate the dose due to incorporation on the basis of metabolic models (ICRP 1978 and ICRP 1979) is explained. The main data (such as half life, mean frequency per decay, mean energy in keV) are given for I-123, I-125, I-129, I-131, I-132, I-133, I-134, and I-135 (ICRP-30) and listed in tables. (orig./HP) [de

  2. Effects of propranolol on conversational reciprocity in autism spectrum disorder: a pilot, double-blind, single-dose psychopharmacological challenge study.

    Science.gov (United States)

    Zamzow, Rachel M; Ferguson, Bradley J; Stichter, Janine P; Porges, Eric C; Ragsdale, Alexandra S; Lewis, Morgan L; Beversdorf, David Q

    2016-04-01

    Pharmacological intervention for autism spectrum disorder (ASD) is an important addition to treatment, yet currently available agents target co-morbid psychiatric concerns, such as aggression and irritability. Propranolol, a beta-adrenergic antagonist with anxiolytic effects, has been shown to improve verbal fluency and working memory in adults and adolescents with ASD in single-dose challenges. The present pilot study explores the acute effects of propranolol on a measure of conversational reciprocity in this population. We also examined whether autonomic activity and anxiety moderate or mediate response to the drug, given relationships between these variables and ASD, as well as the drug's effects. In a within-subject crossover design, 20 individuals with ASD received a single dose of propranolol or placebo during two sessions in a double-blinded, counterbalanced manner. After drug administration, participants performed a conversational reciprocity task by engaging in a short conversation with the researcher. Measurements of autonomic activity and anxiety were obtained before and after drug administration. Propranolol significantly improved performance on the conversational reciprocity task total [d = 0.40] and nonverbal communication domain scores when compared to the placebo condition. However, neither autonomic activity nor anxiety was significantly associated with drug response. Acute propranolol administration improved conversational reciprocity in ASD. Further exploration of these preliminary findings, as well as other potential treatment response predictors, with serial doses is warranted.

  3. VizieR Online Data Catalog: Flux conversion factors for the Swift/UVOT filters (Brown+, 2016)

    Science.gov (United States)

    Brown, P. J.; Breeveld, A.; Roming, P. W. A.; Siegel, M.

    2016-10-01

    The conversion of observed magnitudes (or the actual observed photon or electron count rates) to a flux density is one of the most fundamental calculations. The flux conversions factors for the six Swift/UVOT filters are tabulated in Table1. (1 data file).

  4. Biomass recalcitrance: a multi-scale, multi-factor, and conversion-specific property.

    Science.gov (United States)

    McCann, Maureen C; Carpita, Nicholas C

    2015-07-01

    Recalcitrance of plant biomass to enzymatic hydrolysis for biofuel production is thought to be a property conferred by lignin or lignin-carbohydrate complexes. However, chemical catalytic and thermochemical conversion pathways, either alone or in combination with biochemical and fermentative pathways, now provide avenues to utilize lignin and to expand the product range beyond ethanol or butanol. To capture all of the carbon in renewable biomass, both lignin-derived aromatics and polysaccharide-derived sugars need to be transformed by catalysts to liquid hydrocarbons and high-value co-products. We offer a new definition of recalcitrance as those features of biomass which disproportionately increase energy requirements in conversion processes, increase the cost and complexity of operations in the biorefinery, and/or reduce the recovery of biomass carbon into desired products. The application of novel processing technologies applied to biomass reveal new determinants of recalcitrance that comprise a broad range of molecular, nanoscale, and macroscale factors. Sampling natural genetic diversity within a species, transgenic approaches, and synthetic biology approaches are all strategies that can be used to select biomass for reduced recalcitrance in various pretreatments and conversion pathways. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  5. Defining the Minimal Factors Required for Erythropoiesis through Direct Lineage Conversion

    Directory of Open Access Journals (Sweden)

    Sandra Capellera-Garcia

    2016-06-01

    Full Text Available Erythroid cell commitment and differentiation proceed through activation of a lineage-restricted transcriptional network orchestrated by a group of well characterized genes. However, the minimal set of factors necessary for instructing red blood cell (RBC development remains undefined. We employed a screen for transcription factors allowing direct lineage reprograming from fibroblasts to induced erythroid progenitors/precursors (iEPs. We show that Gata1, Tal1, Lmo2, and c-Myc (GTLM can rapidly convert murine and human fibroblasts directly to iEPs. The transcriptional signature of murine iEPs resembled mainly that of primitive erythroid progenitors in the yolk sac, whereas addition of Klf1 or Myb to the GTLM cocktail resulted in iEPs with a more adult-type globin expression pattern. Our results demonstrate that direct lineage conversion is a suitable platform for defining and studying the core factors inducing the different waves of erythroid development.

  6. A conversion method of air kerma from the primary, scatter, and leakage radiations to effective dose for calculating x-ray shielding barriers in mammography

    International Nuclear Information System (INIS)

    Kharrati, Hedi

    2005-01-01

    In this study, a new approach has been introduced for derivation of the effective dose from air kerma to calculate shielding requirements in mammography facilities. This new approach has been used to compute the conversion coefficients relating air kerma to the effective dose for the mammography reference beam series of the Netherlands Metrology Institute Van Swinden Laboratorium, National Institute of Standards and Technology, and International Atomic Energy Agency laboratories. The results show that, in all cases, the effective dose in mammography energy range is less than 25% of the incident air kerma for the primary and the scatter radiations and does not exceed 75% for the leakage radiation

  7. Measurement of secondary cosmic radiation and calculation of associated dose conversion coefficients for humans; Messung sekundaerer kosmischer Strahlung und Berechnung der zugehoerigen Dosiskonversionskoeffizienten fuer den Menschen

    Energy Technology Data Exchange (ETDEWEB)

    Simmer, Gregor

    2012-04-11

    Due to secondary cosmic radiation (SCR), pilots and flight attendants receive elevated effective doses at flight altitudes. For this reason, since 2003 aircrew members are considered as occupationally exposed, in Germany. This work deals with the calculation of dose conversion coefficients (DCC) for protons, neutrons, electrons, positrons, photons and myons, which are crucial for estimation of effective dose from SCR. For the first time, calculations were performed combining Geant4 - a Monte Carlo code developed at CERN - with the voxel phantoms for the reference female and male published in 2008 by ICRP and ICRU. Furthermore, measurements of neutron fluence spectra - which contribute the major part to the effective dose of SCR - were carried out at the Environmental Research Station Schneefernerhaus (UFS) located at 2650 m above sea level nearby the Zugspitze mountain, Germany. These measured neutron spectra, and additionally available calculated spectra, were then folded with the DCC calculated in this work, and effective dose rates for different heights were calculated.

  8. Total Protein Content Determination of Microalgal Biomass by Elemental Nitrogen Analysis and a Dedicated Nitrogen-to-Protein Conversion Factor

    Energy Technology Data Exchange (ETDEWEB)

    Laurens, Lieve M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Olstad-Thompson, Jessica L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Templeton, David W [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-02

    Accurately determining protein content is important in the valorization of algal biomass in food, feed, and fuel markets, where these values are used for component balance calculations. Conversion of elemental nitrogen to protein is a well-accepted and widely practiced method, but depends on developing an applicable nitrogen-to-protein conversion factor. The methodology reported here covers the quantitative assessment of the total nitrogen content of algal biomass and a description of the methodology that underpins the accurate de novo calculation of a dedicated nitrogen-to-protein conversion factor.

  9. Energy-dependency correction factors for the digital dosimeters using in NMD environment dose assessment

    International Nuclear Information System (INIS)

    Lai, Y.C.; Huang, Y. F.; Chen, Y.W.

    2008-01-01

    Full text: Short-term environment dose-rate assessments using real-time digital dosimeters within a Nuclear Medicine Department (NMD) are gaining more world-wide uses recently. In the past, conventional ion chamber-type survey-meters are used dominantly in environmental dose rates evaluation. Although it has suffered less gamma energy-dependency, but it is less sensitive in comparison with other digital dosimeters and more bulky in design that can hardly make it into a pocket size application. With modern electronic advancement and its shrinking in physical size, real-time personal dosimeter nowadays has gaining more popular to use a miniature G-M counter or a solid-state diode sensor, or even a NaI(Tl) scintillation device for ambient radiation monitoring. Radiation sensor operated in pulse-mode can never been used in doses or dose rates determination since each digital pulse has carried no energy information of the impinging gamma ray being interactive with, especially in the G-M counter or the diode sensor case. The raw count rates measured from a pulse-mode device are heavily dependent on the packaging of the sensor to make it less energy-sensitive. The doses or dose rates are then calculated by using a built-in conversion factor, based on a Cs-137 beam source calibration data conducted by various manufacturing vendors, to convert its raw counts into a so-called dose or dose-rate unit. In this study, we have focused our interests in the low energy response of the digital dosimeters from several brands currently for our in-house uses. Mainly, Tc-99m and I-131 in point sources and water phantoms detection configurations have been deployed to simulate our NMD outpatients for environment radiation monitoring purpose. The energy-dependent correction factors of the digital dosimeters will be evaluated by using calibrated Tc-99m or I-131 standard sources directly that has much lower gamma energy than the Cs-137 beam source of 661 keV. In the near future, we would

  10. Two factors influencing dose reconstruction in low dose range: the variability of BKG intensity on one individual and water content

    International Nuclear Information System (INIS)

    Zhang, Tengda; Zhang, Wenyi; Zhao, Zhixin; Zhang, Haiying; Ruan, Shuzhou; Jiao, Ling

    2016-01-01

    A fast and accurate retrospective dosimetry method for the triage is very important in radiation accidents. Electron paramagnetic resonance (EPR) fingernail dosimetry is a promising way to estimate radiation dose. This article presents two factors influencing dose reconstruction in low dose range: the variability of background signal (BKG) intensity on one individual and water content. Comparing the EPR spectrum of dried and humidified fingernail samples, it is necessary to add a procedure of dehydration before EPR measurements, so as to eliminate the deviation caused by water content. Besides, the BKGs of different fingers' nails are not the same as researchers thought previously, and the difference between maximum and minimum BKG intensities of one individual can reach 55.89 %. Meanwhile, the variability of the BKG intensity among individuals is large enough to impact precise dose reconstruction. Water within fingernails and instability of BKG are two reasons that cause the inaccuracy of radiation dose reconstruction in low-dosage level. (authors)

  11. Effect of Previous Abdominal Surgery on Laparoscopic Liver Resection: Analysis of Feasibility and Risk Factors for Conversion.

    Science.gov (United States)

    Cipriani, Federica; Ratti, Francesca; Fiorentini, Guido; Catena, Marco; Paganelli, Michele; Aldrighetti, Luca

    2018-03-28

    Previous abdominal surgery has traditionally been considered an additional element of difficulty to later laparoscopic procedures. The aim of the study is to analyze the effect of previous surgery on the feasibility and safety of laparoscopic liver resection (LLR), and its role as a risk factor for conversion. After matching, 349 LLR in patients known for previous abdominal surgery (PS group) were compared with 349 LLR on patients with a virgin abdomen (NPS group). Subgroup analysis included 161 patients with previous upper abdominal surgery (UPS subgroup). Feasibility and safety were evaluated in terms of conversion rate, reasons for conversion and outcomes, and risk factors for conversion assessed via uni/multivariable analysis. Conversion rate was 9.4%, and higher for PS patients compared with NPS patients (13.7% versus 5.1%, P = .021). Difficult adhesiolysis resulted the commonest reason for conversion in PS group (5.7%). However, operative time (P = .840), blood loss (P = .270), transfusion (P = .650), morbidity rate (P = .578), hospital stay (P = .780), and R1 rate (P = .130) were comparable between PS and NPS group. Subgroup analysis confirmed higher conversion rates for UPS patients (23%) compared with both NPS (P = .015) and PS patients (P = .041). Previous surgery emerged as independent risk factor for conversion (P = .033), alongside the postero-superior location and major hepatectomy. LLR are feasible in case of previous surgery and proved to be safe and maintain the benefits of LLR carried out in standard settings. However, a history of surgery should be considered a risk factor for conversion.

  12. Forest Conversion, Agricultural Transitions and the Influence of Multi-scale Market Factors in Southwest Cameroon

    Science.gov (United States)

    Ordway, E.; Lambin, E.; Asner, G. P.

    2015-12-01

    The changing structure of demand for commodities associated with food security and energy has had a startling impact on land use change in tropical forests in recent decades. Yet, the composition of conversion in the Congo basin remains a major uncertainty, particularly with regards to the scale of drivers of change. Owing to rapid expansion of production globally and longstanding historical production locally in the Congo basin, oil palm offers a lens through which to evaluate local land use decisions across a spectrum of small- to large-scales of production as well as interactions with regional and global supply chains. We examined the effect of global commodity crop expansion on land use change in Southwest Cameroon using a mixed-methods approach to integrate remote sensing, field surveys and socioeconomic data. Southwest Cameroon (2.5 Mha) has a long history of large- and small-scale agriculture, ranging from mixed crop subsistence agriculture to large monocrop plantations of oil palm, cocoa, and rubber. Trends and spatial patterns of forest conversion and agricultural transitions were analyzed from 2000-2015 using satellite imagery. We used economic, demographic and field survey datasets to assess how regional and global market factors and local commodity crop decisions affect land use patterns. Our results show that oil palm is a major commodity crop expanding in this region, and that conversion is occurring primarily through expansion by medium-scale producers and local elites. Results also indicate that global and regional supply chain dynamics influence local land use decision making. This research contributes new information on land use patterns and dynamics in the Congo basin, an understudied region. More specifically, results from this research contribute information on recent trends of oil palm expansion in Cameroon that will be used in national land use planning strategies.

  13. Conversion of output factor from square field into rectangular field in electron beam

    CERN Document Server

    Wang Jian Hua; Xu Yi Fei

    2002-01-01

    Objective: A simple and accurate calculation method was designed to convert output factor from square field into rectangular field in electron beam, which can be easily implemented in clinical practice. Methods: 6, 12, 15 MeV electron beam, field size 6.0 cm x 7.5 cm, 5.0 cm x 10.0 cm, 6.0 cm x 12.0 cm, TL3000C dosimeter and source-to-surface distance method were used in dose measurement. The measured dose values were compared with the calculated ones from three theoretical equations with the conformation evaluated. Results: The calculated dose values from three theoretical equations differed from the measured ones by 0.23%, 1.30% and 1.10% (6 MeV), 0.63%, 0.90% and 0.73% (12 MeV), 0.50%, 1.80% and 3.40% (15 MeV), conforming best to the equation OUF (X, Y)=[OUF(X,X). OUF(Y,Y)] sup 1 sup / sup 2. When the size of the field was longer than Rp, the difference between the calculated values and measured ones was relatively very small. Conclusions: The output factor in rectangular fields can be accurately calculate...

  14. Determination of the conversion coefficient for ambient dose equivalent, H(10), from air kerma measurements; Determinacion del coeficiente de conversion para la dosis equivalente ambiental, H*(10), a partir de mediciones de kerma en aire

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez J, F. [UNAM, Facultad de Ciencias, Circuito Exterior, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Alvarez R, J. T., E-mail: trinidad.alvarez@inin.gob.mx [ININ, Departamento de Metrologia de Radiaciones Ionizantes, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2015-09-15

    Namely the operational magnitudes can be determined by the product of a conversion coefficient by exposure air kerma or fluence, etc. In particular in Mexico for the first time is determined the conversion coefficient (Cc) for operational magnitude Environmental Dose Equivalent H(10) by thermoluminescence dosimetry (TLD) technique. First 30 TLD-100 dosimeters are calibrated in terms of air kerma, then these dosimeters are irradiated inside a sphere ICRU type of PMMA and with the aid of theory cavity the absorbed dose in PMMA is determined at a depth of 10 mm within the sphere D{sub PMMA}(10), subsequently absorbed dose to ICRU tissue is corrected and the dose equivalent H(10) is determined. The Cc is determined as the ratio of H(10)/K{sub a} obtaining a value of 1.20 Sv Gy{sup -1} with a u{sub c}= 3.66%, this being consistent with the published value in ISO-4037-3 of 1.20 Sv Gy{sup -1} with a u{sub c}= 2%. (Author)

  15. Age-dependent dose factors and dose limits of annual radioactivity uptake with unsealed radioactive substances by occupationally exposed persons

    International Nuclear Information System (INIS)

    Kaul, A.; Nosske, D; Elsasser, U; Roedler, H.D.; Henrichs, K.

    1986-01-01

    The dose factors have been calculated on the basis of the ICRP models for dosimetric and metabolistic assessment, and are laid open in accordance with Annex XI ( to sec. 45 sub-section (2)) of the amended version of the Radiation Protection Ordinance. The contribution in hand explains the scientific fundamentals and results of the calculations of dose factors relating to inhalation and ingestion of unsealed radioactive substances by adult reference man, and age-dependent factors calculated for children and adolescents. Further, annual limits of uptake by occupationally exposed persons, as calculated on the basis of primary dose limits pursunant to the draft amendment presented by the Federal Interior Minister, are compared with relevant data given by the ICRP and EC institutions. (orig./DG) [de

  16. A small-form-factor piezoelectric vibration energy harvester using a resonant frequency-down conversion

    Directory of Open Access Journals (Sweden)

    Kyung Ho Sun

    2014-10-01

    Full Text Available While environmental vibrations are usually in the range of a few hundred Hertz, small-form-factor piezoelectric vibration energy harvesters will have higher resonant frequencies due to the structural size effect. To address this issue, we propose a resonant frequency-down conversion based on the theory of dynamic vibration absorber for the design of a small-form-factor piezoelectric vibration energy harvester. The proposed energy harvester consists of two frequency-tuned elastic components for lowering the first resonant frequency of an integrated system but is so configured that an energy harvesting beam component is inverted with respect to the other supporting beam component for a small form factor. Furthermore, in order to change the unwanted modal characteristic of small separation of resonant frequencies, as is the case with an inverted configuration, a proof mass on the supporting beam component is slightly shifted toward a second proof mass on the tip of the energy harvesting beam component. The proposed small-form-factor design capability was experimentally verified using a fabricated prototype with an occupation volume of 20 × 39 × 6.9 mm3, which was designed for a target frequency of as low as 100 Hz.

  17. A small-form-factor piezoelectric vibration energy harvester using a resonant frequency-down conversion

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kyung Ho; Kim, Young-Cheol [Department of System Dynamics, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 305-343 (Korea, Republic of); Kim, Jae Eun, E-mail: jekim@cu.ac.kr [School of Mechanical and Automotive Engineering, Catholic University of Daegu, 13-13 Hayang-Ro, Hayang-Eup, Gyeongsan-Si, Gyeongsangbuk-Do 712-702 (Korea, Republic of)

    2014-10-15

    While environmental vibrations are usually in the range of a few hundred Hertz, small-form-factor piezoelectric vibration energy harvesters will have higher resonant frequencies due to the structural size effect. To address this issue, we propose a resonant frequency-down conversion based on the theory of dynamic vibration absorber for the design of a small-form-factor piezoelectric vibration energy harvester. The proposed energy harvester consists of two frequency-tuned elastic components for lowering the first resonant frequency of an integrated system but is so configured that an energy harvesting beam component is inverted with respect to the other supporting beam component for a small form factor. Furthermore, in order to change the unwanted modal characteristic of small separation of resonant frequencies, as is the case with an inverted configuration, a proof mass on the supporting beam component is slightly shifted toward a second proof mass on the tip of the energy harvesting beam component. The proposed small-form-factor design capability was experimentally verified using a fabricated prototype with an occupation volume of 20 × 39 × 6.9 mm{sup 3}, which was designed for a target frequency of as low as 100 Hz.

  18. Evaluation of the fluence to dose conversion coefficients for high energy neutrons using a voxel phantom coupled with the GEANT4 code

    CERN Document Server

    Paganini, S

    2005-01-01

    Crews working on present-day jet aircraft are a large occupationally exposed group with a relatively high average effective dose from Galactic cosmic radiation. Crews of future high-speed commercial flying at higher altitudes would be even more exposed. To help reduce the significant uncertainties in calculations of such exposures, the male adult voxels phantom MAX, developed in the Nuclear Energy Department of Pernambuco Federal University in Brazil, has been coupled with the Monte Carlo simulation code GEANT4. This toolkit, distributed and upgraded from the international scientific community of CERN/Switzerland, simulates thermal to ultrahigh energy neutrons transport and interactions in the matter. The high energy neutrons are pointed as the component that contribute about 70% of the neutron effective dose that represent the 35% to 60% total dose at aircraft altitude. In this research calculations of conversion coefficients from fluence to effective dose are performed for neutrons of energies from 100 MeV ...

  19. Dose factors for contamination of skin and clothing

    International Nuclear Information System (INIS)

    Henrichs, K.; Eiberweiser, C.; Paretzke, H.G.

    1985-11-01

    Methods are described for quantifying the radiation dose administered through radioactive contamination of the skin (and of clothing, in an approximative manner). The calculated results are presented in tables. The dose values established are of significance with regard to radiological assessment of contamination for the definition of dose limits, and for use as a criterion to select appropriate decontamination activities. Alpha, beta and monoenergetic electrons are of importance for estimating the absorbed dose in various skin depths, whereas for other body regions (as e.g. body organs) photon radiation has to be considered. The calculations are based on the assumption of homogeneous exposure of the skin, with the linear extension being large compared to the range of the emitted particle radiation. In order to be able to take into account potential penetration of radioactivity into deeper skin layers by diffusion or solution processes, the calculations have been made for contamination into various depths of the horny layers of the epidermis. The scheme of specific absorbed fraction (SAF) served as a basis for the uniform treatment of different radiation types for the calculation of dose values. (orig./HP) [de

  20. Fluence to absorbed foetal dose conversion coefficients for photons in 50 keV-10 GeV calculated using RPI-P models

    International Nuclear Information System (INIS)

    Taranenko, V.; Xu, X.G.

    2008-01-01

    Radiation protection of pregnant females and the foetus against ionising radiation is of particular importance to radiation protection due to high foetal radiosensitivity. The only available set of foetal conversion coefficients for photons is based on stylised models of simplified anatomy. Using the RPI-P series of pregnant female and foetus models representing 3-, 6- and 9-month gestation, a set of new fluence to absorbed foetal dose conversion coefficients has been calculated. The RPI-P anatomical models were developed using novel 3D geometry modelling techniques. Organ masses were adjusted to agree within 1% with the ICRP reference data for a pregnant female. Monte Carlo dose calculations were carried out using the MCNPX and Penelope codes for external 50 keV-10 GeV photon beams of six standard configurations. The models were voxelised at 3-mm voxel resolution. Conversion coefficients were tabulated for the three gestational periods for the whole foetus and brain. Comparison with previously published data showed deviations up to 120% for the foetal doses at 50 keV. The discrepancy can be primarily ascribed to anatomical differences. Comparison with published data for five major mother organs is also provided for the 3-month model. Since the RPI-P models exhibit a high degree of anatomical realism, the reported dataset is recommended as a reference for radiation protection of the foetus against external photon exposure. (authors)

  1. Influence of production factors on feed intake and feed conversion ratio of grow-finishing pigs

    Directory of Open Access Journals (Sweden)

    Caio Abércio da Silva

    2017-05-01

    Full Text Available The aim of this study was to identify and quantify, through mathematical models, the production factors of grow-finishing (GF phases that influence the daily feed intake (DFI and feed conversion ratio (FCR in pigs. Sixty-five GF farms were evaluated between 2010 and 2013, linked to a cooperative system located in the western Parana State, Brazil, representing 463 batches, with a mean of 642.79 ± 363.29 animals per batch, equalling approximately 300,000 animals. Forty production factors were considered that related to management, sanitation, installations and equipment, nutrition, genetics and environment on the farms. The DFI was influenced by the barn's position relative to the sun (P = 0.048, initial body weight (P < 0.0001 and final body weight (P < 0.0001. It was observed that the FCR was influenced by the barn’s position relative to the sun (P = 0.0001, the use of humidifiers/misting (P = 0.03, the presence of composters (P = 0.006, trees on the sides of barns (P < 0.045, the initial body weight of the pigs (P < 0.0001 and duration of the grow-finishing phase (P < 0.0001. The variables selected in the models explained approximately 44 and 20% of the total variance in the DFI and FCR, respectively, demonstrating that this resource is a good tool for interpreting the factors related to the parameters evaluated.

  2. Guideline values for skin decontamination measures based on nuclidspecific dose equivalent rate factors

    International Nuclear Information System (INIS)

    Pfob, H.; Heinemann, G.

    1992-01-01

    Corresponding dose equivalent rate factors for various radionuclides are now available for determining the skin dose caused by skin contamination. These dose equivalent rate factors take into account all contributions from the types of radiation emitted. Any limits for skin decontamination measures are nowhere contained or determined yet. However, radiological protection does in practice require at least guideline values in order to prevent unsuitable or detrimental measures that can be noticed quite often. New calculations of dose equivalent rate factors for the skin now make the recommendation of guideline values possible. (author)

  3. MO-E-17A-12: Direct Realization of the CT Dose to Phantom: Energy to Heat Conversion in Polyethylene Using Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Chen-Mayer, H; Tosh, R [NIST, Gaithersburg, MD (United States)

    2014-06-15

    Purpose: To develop a primary reference standard for absorbed dose to phantom for medical CT dosimetry. CT dosimetry relies on the implementation of the CTDI standard based on air kerma. We are taking a step toward an absorbed dose to water standard by first investigating the dose in a solid phantom. By directly measuring the heat converted from the incident radiation, the absorbed dose in the phantom at a point can be assessed with primary methods without relying on indirect conversions. Methods: The calorimeter contains two small thermistors embedded in a removable PE “core” inserted into the cylindrical HDPE phantom. A core made with polystyrene (PS) was also tested because of its purportedly negligible heat defect. Measurements were made using the two cores and with a calibrated ionization chamber in a CT beam. The air chamber values were converted to the dose to medium using appropriate stopping-power ratios from the literature, and then compared to the thermal data. Results: The PS core data yielded a dose of 1.3 times (4-run average, 3% std. dev.) higher than the converted chamber value, whereas the PE core data were inexplicably higher. The possible systematic errors include 1) excess heat from the thermistors, 2) in PE the exothermic chemical reactions, 3) uncertainties of the specific heat capacities of the materials, 4) thermal drift, and 5) theoretical conversion of chamber values. Monte Carlo simulations and finite element heat transfer calculations were performed to address some of these issues. The general validity was assessed in a 6 MV photon beam with an entirely different calibration scheme. Conclusion: This study demonstrates the feasibility but also revealed the difficulty in developing a new primary reference standard for absorbed dose to material for CT. Additional experimental and theoretical work is planned to achieve our goal.

  4. Human and technical factors in the doses reduction and optimization at Cogema/Marcoule

    International Nuclear Information System (INIS)

    Bourgogne, J.L.

    1998-01-01

    In the case of Cogema/Marcoule, the constant decrease of radiation doses is attributed to three factors: technical with a surveillance system and doses optimization, relational with the promotion of confidence in teams of radiation protection services as an acceptation factor of radiation protection techniques and psychological with an evolution of minds towards the ALARA approach. (N.C.)

  5. A method to adjust radiation dose-response relationships for clinical risk factors

    DEFF Research Database (Denmark)

    Appelt, Ane Lindegaard; Vogelius, Ivan R

    2012-01-01

    Several clinical risk factors for radiation induced toxicity have been identified in the literature. Here, we present a method to quantify the effect of clinical risk factors on radiation dose-response curves and apply the method to adjust the dose-response for radiation pneumonitis for patients...

  6. Dissecting variation in biomass conversion factors across China's forests: implications for biomass and carbon accounting.

    Science.gov (United States)

    Luo, Yunjian; Zhang, Xiaoquan; Wang, Xiaoke; Ren, Yin

    2014-01-01

    Biomass conversion factors (BCFs, defined as the ratios of tree components (i.e. stem, branch, foliage and root), as well as aboveground and whole biomass of trees to growing stock volume, Mg m-3) are considered as important parameters in large-scale forest biomass carbon estimation. To date, knowledge of possible sources of the variation in BCFs is still limited at large scales. Using our compiled forest biomass dataset of China, we presented forest type-specific values of BCFs, and examined the variation in BCFs in relation to forest type, stand development and environmental factors (climate and soil fertility). BCFs exhibited remarkable variation across forest types, and also were significantly related to stand development (especially growing stock volume). BCFs (except Stem BCF) had significant relationships with mean annual temperature (MAT) and mean annual precipitation (MAP) (Pforest carbon estimates, we should apply values of BCFs for a specified forest type, and also consider climatic and edaphic effects, especially climatic effect, in developing predictive models of BCFs (except Stem BCF).

  7. Alternatives to dose, quality factor and dose equivalent for low level irradiation

    International Nuclear Information System (INIS)

    Sondhaus, C.A.; Bond, V.P.; Feinendegen, L.E.

    1988-01-01

    Randomly occurring energy deposition events produced by low levels of ionizing radiation interacting with tissue deliver variable amounts of energy to the sensitive target volumes within a small fraction of the cell population. A model is described in which an experimentally derived function relating event size to cell response probability operates mathematically on the microdosimetric event size distribution characterizing a given irradiation and thus determines the total fractional number of responding cells; this fraction measures the effectiveness of the given radiation. Normalizing to equal numbers of events produced by different radiations and applying this cell response or hit size effectiveness function (HSEF) should define radiation quality, or relative effectiveness, on a more nearly absolute basis than do the absorbed dose and dose evaluation, which are confounded when applied to low level irradiations. Examples using both calculation and experimental data are presented. 15 refs., 18 figs

  8. Cathecol-O-methyl transferase Val158Met genotype is not a risk factor for conversion disorder.

    Science.gov (United States)

    Armagan, E; Almacıoglu, M L; Yakut, T; Köse, A; Karkucak, M; Köksal, O; Görükmez, O

    2013-03-19

    Alterations in catechol-O-methyltransferase (COMT) activity are involved in various types of neurological disorders. We examined a possible association between the COMT Val158Met polymorphism and conversion disorder in a study of 48 patients with conversion disorder and 48 control patients. In the conversion disorder group, 31 patients were Val/Met heterozygotes, 15 patients were Val/Val homozygotes and 2 patients were Met/Met homozygotes. In the control group, 32 patients were Val/Met heterozygotes and 16 patients were Val/Val homozygotes. There was no significant difference between the groups. We conclude that the COMT Val158Met genotype is quite common in Turkey and that it is not a risk factor for conversion disorder in the Turkish population.

  9. Lung doses from radon in dwellings and influencing factors

    International Nuclear Information System (INIS)

    Stranden, E.

    1980-01-01

    The radon concentration in Norwegian dwellings and the lung doses received by the Norwegian population are reported. The biological effects of these doses are discussed. The mean value of radon-daughters in Norwegian dwellings was found to be about 7x10 -3 WL (working levels). This corresponds to an annual exposure of about 0.3 WLM (working level months). From studies of the lung cancer statistics of Norway, this exposure may account for about 10% of the annual lung cancer cases in Norway. The variations in the radon concentration inside dwellings are discussed, and the influence of exhalation, ventilation and meteorological parameters upon the respiratory dosage is studied. From the risk estimates performed, the consequences of an increased indoor radon concentration due to reduced ventilation or introduction of building materials with high radium concentrations are discussed. From comparison of the population doses from different sources of radiation, it is evident that a possible future increase in the radon concentration in dwellings is one of the most serious radiation protection problems of our time. (author)

  10. Factors Affecting Time to Sputum Culture Conversion in Adults with Pulmonary Tuberculosis: A Historical Cohort Study without Censored Cases.

    Science.gov (United States)

    Kanda, Rie; Nagao, Taishi; Tho, Nguyen Van; Ogawa, Emiko; Murakami, Yoshitaka; Osawa, Makoto; Saika, Yoshinori; Doi, Kenji; Nakano, Yasutaka

    2015-01-01

    In patients with pulmonary tuberculosis (TB), shortening the time to sputum culture conversion is desirable to reduce the likelihood of mycobacterial transmission. A persistent positive sputum culture after 2 months of treatment is reported to be associated with the presence of cavitation and the extent of disease on chest X-ray, high colony count, diabetes mellitus, and smoking. However, little is known about factors affecting the time to sputum culture conversion. This study was conducted to evaluate factors affecting the time to sputum culture conversion throughout the course of treatment in adults with pulmonary TB. This study was performed using a database of the medical records of patients with active pulmonary TB who were treated at Hirakata Kohsai Hospital in Hirakata City, Osaka, Japan, from October 2000 to October 2002. Cox proportional-hazards analysis was used to evaluate factors affecting the time to sputum culture conversion after adjusting for potential confounders. The data of 86 patients with pulmonary TB were analyzed. The median time to sputum culture conversion was 39 days, and the maximum time was 116 days. The Cox proportional-hazards analysis showed that a higher smear grading (HR, 0.40; 95%CI, 0.23-0.71) and a history of ever smoking (HR, 0.48; 95%CI, 0.25-0.94) were associated with delayed sputum culture conversion. High smear grading and smoking prolonged the time to sputum culture conversion in adults with pulmonary TB. To effectively control TB, measures to decrease the cigarette smoking rate should be implemented, in addition to early detection and timely anti-TB treatment.

  11. Factors Affecting Time to Sputum Culture Conversion in Adults with Pulmonary Tuberculosis: A Historical Cohort Study without Censored Cases.

    Directory of Open Access Journals (Sweden)

    Rie Kanda

    Full Text Available In patients with pulmonary tuberculosis (TB, shortening the time to sputum culture conversion is desirable to reduce the likelihood of mycobacterial transmission. A persistent positive sputum culture after 2 months of treatment is reported to be associated with the presence of cavitation and the extent of disease on chest X-ray, high colony count, diabetes mellitus, and smoking. However, little is known about factors affecting the time to sputum culture conversion. This study was conducted to evaluate factors affecting the time to sputum culture conversion throughout the course of treatment in adults with pulmonary TB.This study was performed using a database of the medical records of patients with active pulmonary TB who were treated at Hirakata Kohsai Hospital in Hirakata City, Osaka, Japan, from October 2000 to October 2002. Cox proportional-hazards analysis was used to evaluate factors affecting the time to sputum culture conversion after adjusting for potential confounders.The data of 86 patients with pulmonary TB were analyzed. The median time to sputum culture conversion was 39 days, and the maximum time was 116 days. The Cox proportional-hazards analysis showed that a higher smear grading (HR, 0.40; 95%CI, 0.23-0.71 and a history of ever smoking (HR, 0.48; 95%CI, 0.25-0.94 were associated with delayed sputum culture conversion.High smear grading and smoking prolonged the time to sputum culture conversion in adults with pulmonary TB. To effectively control TB, measures to decrease the cigarette smoking rate should be implemented, in addition to early detection and timely anti-TB treatment.

  12. Fluence to Effective Dose and Effective Dose Equivalent Conversion Coefficients for Photons from 50 KeV to 10 GeV

    International Nuclear Information System (INIS)

    Ferrari, A.; Pelliccioni, M.; Pillon, M.

    1996-07-01

    Effective dose equivalent and effective dose per unit photon fluence have been calculated by the FLUKA code for various geometrical conditions of irradiation of an anthropomorphic phantom placed in a vacuum. Calculations have been performed for monoenergetic photons of energy ranging from 50 keV to 10 GeV. The agreement with the results of other authors, when existing, is generally very satisfactory

  13. Why change the x-ray conversion factors in ANSI N13.11?

    International Nuclear Information System (INIS)

    Zeman, G.H.; Soares, C.; Devine, R.T.

    1991-01-01

    The personnel dosimetry calibration procedures defined in ANSI N13.11-1983 revolutionized and standardized the practice of personnel dosimetry in the United States. Because of new data and concepts which have appeared in the last decade, it is now necessary to update the original procedures. The calibration scheme outlined in this paper is consistent with the latest concepts and recommendations of the International Commission on Radiation Units and Measurements and incorporates current information from the National Institute of Standards and Technology on ionization chamber calibrations and x-ray spectral data. Advantages of the proposed scheme include the conceptual simplicity in using a tissue equivalent slab phantom to represent an individual person's body for defining the reference dose equivalent quantities; this also makes it possible to carry out practical measurements of these quantities. For testing purposes, the PMMA phantom has proven to be practical and rugged, and it should continue to be used as the US standard phantom for test irradiations. Correction of the basic dose equivalent quantities for differences in phantom backscatter is now possible due to the availability of BSF results for different shapes and compositions of material. Disadvantages of the proposed calibration scheme include the fact that some of the Cx factors will change by as much as 20%, while others will remain relatively unchanged

  14. Calculation of Dose Gamma Ray Build up Factor in Some ...

    African Journals Online (AJOL)

    The gamma ray buildup factor was calculated by analyzing the narrow- beam and broad-beam geometry equations using Taylor's formula for isotropic sources and homogeneous materials. The buildup factor was programmed using MATLAB software to operate with any radiation energy (E), atomic number (Z) and the ...

  15. Identifying and Exploring Factors Affecting Embodied Conversational Agent Social Presence for Interpersonal Skills Training

    Science.gov (United States)

    Chuah, Joon Hao

    2013-01-01

    Embodied conversational agents (ECAs) have been used as virtual conversational partners in interpersonal skills training applications such as medical interviews, military decision making, and cultural training. Ideally, in interpersonal skills training users will perceive and treat the ECAs the same as they would real people. The perception and…

  16. Conversion factors from counts to chemical ratios for the EURITRACK tagged neutron inspection system

    International Nuclear Information System (INIS)

    El Kanawati, W.; Perot, B.; Carasco, C.; Eleon, C.; Valkovic, V.; Sudac, D.; Obhodas, J.

    2011-01-01

    The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) uses 14 MeV neutrons produced by the 3 H(d,n) 4 H fusion reaction to detect explosives and narcotics in cargo containers. Reactions induced by fast neutrons produce gamma rays, which are detected in coincidence with the associated alpha particle to determine the neutron direction. In addition, the neutron path length is obtained from a time-of-flight measurement, thus allowing the origin of the gamma rays inside the container to be determined. Information concerning the chemical composition of the target material is obtained from the analysis of the energy spectrum. The carbon, oxygen, and nitrogen relative count contributions must be converted to chemical proportions to distinguish illicit and benign organic materials. An extensive set of conversion factors based on Monte Carlo numerical simulations has been calculated, taking into account neutron slowing down and photon attenuation in the cargo materials. An experimental validation of the method is presented by comparing the measured chemical fractions of known materials, in the form of bare samples or hidden in a cargo container, to their real chemical composition. Examples of application to real cargo containers are also reported, as well as simulated data with explosives and illicit drugs.

  17. Conversion factors from counts to chemical ratios for the EURITRACK tagged neutron inspection system

    Energy Technology Data Exchange (ETDEWEB)

    El Kanawati, W. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Perot, B., E-mail: bertrand.perot@cea.fr [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Carasco, C.; Eleon, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Valkovic, V. [A.C.T.d.o.o., Prilesje 4, 10000 Zagreb (Croatia); Sudac, D.; Obhodas, J. [Ruder Boskovic Institute, Bijenicka c. 54, 10000 Zagreb (Croatia)

    2011-10-21

    The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) uses 14 MeV neutrons produced by the {sup 3}H(d,n){sup 4}H fusion reaction to detect explosives and narcotics in cargo containers. Reactions induced by fast neutrons produce gamma rays, which are detected in coincidence with the associated alpha particle to determine the neutron direction. In addition, the neutron path length is obtained from a time-of-flight measurement, thus allowing the origin of the gamma rays inside the container to be determined. Information concerning the chemical composition of the target material is obtained from the analysis of the energy spectrum. The carbon, oxygen, and nitrogen relative count contributions must be converted to chemical proportions to distinguish illicit and benign organic materials. An extensive set of conversion factors based on Monte Carlo numerical simulations has been calculated, taking into account neutron slowing down and photon attenuation in the cargo materials. An experimental validation of the method is presented by comparing the measured chemical fractions of known materials, in the form of bare samples or hidden in a cargo container, to their real chemical composition. Examples of application to real cargo containers are also reported, as well as simulated data with explosives and illicit drugs.

  18. Calculated neutron air kerma strength conversion factors for a generically encapsulated Cf-252 brachytherapy source

    CERN Document Server

    Rivard, M J; D'Errico, F; Tsai, J S; Ulin, K; Engler, M J

    2002-01-01

    The sup 2 sup 5 sup 2 Cf neutron air kerma strength conversion factor (S sub K sub N /m sub C sub f) is a parameter needed to convert the radionuclide mass (mu g) provided by Oak Ridge National Laboratory into neutron air kerma strength required by modern clinical brachytherapy dosimetry formalisms indicated by Task Group No. 43 of the American Association of Physicists in Medicine (AAPM). The impact of currently used or proposed encapsulating materials for sup 2 sup 5 sup 2 Cf brachytherapy sources (Pt/Ir-10%, 316L stainless steel, nitinol, and Zircaloy-2) on S sub K sub N /m sub C sub f was calculated and results were fit to linear equations. Only for substantial encapsulation thicknesses, did S sub K sub N /m sub C sub f decrease, while the impact of source encapsulation composition is increasingly negligible as Z increases. These findings are explained on the basis of the non-relativistic kinematics governing the majority of sup 2 sup 5 sup 2 Cf neutron interactions. Neutron kerma and energy spectra resul...

  19. Trends of the electricity output, power conversion efficiency, and the grid emission factor in North Korea

    Science.gov (United States)

    Yeo, M. J.; Kim, Y. P.

    2017-12-01

    Recently, concerns about the atmospheric environmental problems in North Korea (NK) have been growing. According to the World Health Organization (WHO) (2017), NK was the first ranked country in mortality rate attributed to household and ambient air pollution in 2012. Reliable energy-related data in NK were needed to understand the characteristics of air quality in NK. However, data from the North Korean government were limited. Nevertheless, we could find specific energy-related data produced by NK in the Project Design Documents (PDDs) of the Clean Development Mechanism (CDM) submitted to the United Nations Framework Convention on Climate Change (UNFCCC). There were the 6 registered CDM projects hosted by North Korea, developed as small hydropower plants. Several data of each power plant, such as the electricity output, connected to the Eastern Power Grid (EPG) or the Western Power Grid (WPG) in North Korea were provided in the CDM PDDs. We (1) figured out the trends of the electricity output, the `power conversion efficiency' which we defined the amount of generated electricity to the supplied input primary energy for power generation, and fuel mix as grid emission factor in NK as using the data produced by NK between 2005 and 2009, (2) discussed the operating status of the thermal power plants in NK, and (3) discussed the energy/environmental-related policies and the priority issues in NK in this study.

  20. A comparison of simple and realistic eye models for calculation of fluence to dose conversion coefficients in a broad parallel beam incident of protons

    International Nuclear Information System (INIS)

    Sakhaee, Mahmoud; Vejdani-Noghreiyan, Alireza; Ebrahimi-Khankook, Atiyeh

    2015-01-01

    Radiation induced cataract has been demonstrated among people who are exposed to ionizing radiation. To evaluate the deterministic effects of ionizing radiation on the eye lens, several papers dealing with the eye lens dose have been published. ICRP Publication 103 states that the lens of the eye may be more radiosensitive than previously considered. Detailed investigation of the response of the lens showed that there are strong differences in sensitivity to ionizing radiation exposure with respect to cataract induction among the tissues of the lens of the eye. This motivated several groups to look deeper into issue of the dose to a sensitive cell population within the lens, especially for radiations with low energy penetrability that have steep dose gradients inside the lens. Two sophisticated mathematical models of the eye including the inner structure have been designed for the accurate dose estimation in recent years. This study focuses on the calculations of the absorbed doses of different parts of the eye using the stylized models located in UF-ORNL phantom and comparison with the data calculated with the reference computational phantom in a broad parallel beam incident of protons with energies between 20 MeV and 10 GeV. The obtained results indicate that the total lens absorbed doses of reference phantom has good compliance with those of the more sensitive regions of stylized models. However, total eye absorbed dose of these models greatly differ with each other for lower energies. - Highlights: • The validation of reference data for the eye was studied for proton exposures. • Two real mathematical models of the eye were imported into the UF-ORNL phantom. • Fluence to dose conversion coefficients were calculated for different eye sections. • Obtained Results were compared with that of assessed by ICRP adult male phantom

  1. Outcomes of visual acuity in carbon ion radiotherapy: Analysis of dose-volume histograms and prognostic factors

    International Nuclear Information System (INIS)

    Hasegawa, Azusa; Mizoe, Jun-etsu; Mizota, Atsushi; Tsujii, Hirohiko

    2006-01-01

    Purpose: To analyze the tolerance dose for retention of visual acuity in patients with head-and-neck tumors treated with carbon ion radiotherapy. Methods and Materials: From June 1994 to March 2000, 163 patients with tumors in the head and neck or skull base region were treated with carbon ion radiotherapy. Analysis was performed on 54 optic nerves (ONs) corresponding to 30 patients whose ONs had been included in the irradiated volume. These patients showed no evidence of visual impairment due to other factors and had a follow-up period of >4 years. All patients had been informed of the possibility of visual impairment before treatment. We evaluated the dose-complication probability and the prognostic factors for the retention of visual acuity in carbon ion radiotherapy, using dose-volume histograms and multivariate analysis. Results: The median age of 30 patients (14 men, 16 women) was 57.2 years. Median prescribed total dose was 56.0 gray equivalents (GyE) at 3.0-4.0 GyE per fraction per day (range, 48-64 GyE; 16-18 fractions; 4-6 weeks). Of 54 ONs that were analyzed, 35 had been irradiated with max ]) resulting in no visual loss. Conversely, 11 of the 19 ONs (58%) irradiated with >57 GyE (D max ) suffered a decrease of visual acuity. In all of these cases, the ONs had been involved in the tumor before carbon ion radiotherapy. In the multivariate analysis, a dose of 20% of the volume of the ON (D 2 ) was significantly associated with visual loss. Conclusions: The occurrence of visual loss seems to be correlated with a delivery of >60 GyE to 20% of the volume of the ON

  2. Genetic Factors Affecting Susceptibility to Low Dose & Low Dose-Rate Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bedford, Joel

    2014-04-18

    Our laboratory has, among other things, developed and used the gamma H2AX focus assay and other chromosomal and cell killing assays to show that differences in this DNA double strand break (dsb) related response can be clearly and distinctly demonstrated for cells which are mildly hyper-radiosensitive such as those associated with A-T heterozygosity. We have found this level of mild hypersensitivity for cells from some 20 to 30 % of apparently normal individuals and from apparently normal parents of Retinoblastoma patients. We found significant differences in gene expression in somatic cells from unaffected parents of Rb patients as compared with normal controls, suggesting that these parents may harbor some as yet unidentified genetic abnormality. In other experiments we sought to determine the extent of differences in normal human cellular reaponses to radiation depending on their irradiation in 2D monolayer vs 3D organized acinar growth conditions. We exmined cell reproductive death, chromosomal aberration induction, and the levels of γ-H2AX foci in cells after single acute gamma-ray doses and immediately after 20 hours of irradiation at a dose rate of 0.0017 Gy/min. We found no significant differences in the dose-responses of these cells under the 2D or 3D growth conditions. While this does not mean such differences cannot occur in other situations, it does mean that they do not generally or necessarily occur. In another series of studies in collaboration with Dr Chuan Li, with supprt from this current grant. We reported a role for apoptotic cell death in promoting wound healing and tissue regeneration in mice. Apoptotic cells released growth signals that stimulated the proliferation of progenitor or stem cells. In yet another collaboration with Dr, B. Chen with funds from this grant, the relative radiosensitivity to cell killing as well as chromosomal instability of 13 DNA-PKcs site-directed mutant cell lines (defective at phosphorylation sites or kinase

  3. Experimental determination of relative light conversion factors of TLD-100 for protons with energies from 2.0 to 9.0 MeV

    International Nuclear Information System (INIS)

    Schmidt, P.; Fellinger, J.; Henniger, J.; Huebner, K.

    1988-01-01

    The efficiency of thermoluminescent (TL) detectors to heavy charged particles is described by the so-called light conversion factor η. Relative light conversion factors for protons, alphas and heavier recoils are needed for the calculation of the neutron sensitivity of TL detectors. Such light conversion factors can be determined experimentally. In this paper a method is presented for the experimental determination of relative light conversion factors. Using the experimental arrangement described, relative light conversion factors for LiF material (TLD-100) for protons were determined. In LiF the relative main peak (peak V) efficiency is always lower than 1. It increases with increasing proton energy whereas the relative efficiency of the high temperature peak (peak VI) shows an opposite dependence on the proton energy. Relative light conversion factors for peak VI clearly exceed 1. (orig.)

  4. SU-F-J-193: Efficient Dose Extinction Method for Water Equivalent Path Length (WEPL) of Real Tissue Samples for Validation of CT HU to Stopping Power Conversion

    International Nuclear Information System (INIS)

    Zhang, R; Baer, E; Jee, K; Sharp, G; Flanz, J; Lu, H

    2016-01-01

    Purpose: For proton therapy, an accurate model of CT HU to relative stopping power (RSP) conversion is essential. In current practice, validation of these models relies solely on measurements of tissue substitutes with standard compositions. Validation based on real tissue samples would be much more direct and can address variations between patients. This study intends to develop an efficient and accurate system based on the concept of dose extinction to measure WEPL and retrieve RSP in biological tissue in large number of types. Methods: A broad AP proton beam delivering a spread out Bragg peak (SOBP) is used to irradiate the samples with a Matrixx detector positioned immediately below. A water tank was placed on top of the samples, with the water level controllable in sub-millimeter by a remotely controlled dosing pump. While gradually lowering the water level with beam on, the transmission dose was recorded at 1 frame/sec. The WEPL were determined as the difference between the known beam range of the delivered SOBP (80%) and the water level corresponding to 80% of measured dose profiles in time. A Gammex 467 phantom was used to test the system and various types of biological tissue was measured. Results: RSP for all Gammex inserts, expect the one made with lung-450 material (<2% error), were determined within ±0.5% error. Depends on the WEPL of investigated phantom, a measurement takes around 10 min, which can be accelerated by a faster pump. Conclusion: Based on the concept of dose extinction, a system was explored to measure WEPL efficiently and accurately for a large number of samples. This allows the validation of CT HU to stopping power conversions based on large number of samples and real tissues. It also allows the assessment of beam uncertainties due to variations over patients, which issue has never been sufficiently studied before.

  5. SU-F-J-193: Efficient Dose Extinction Method for Water Equivalent Path Length (WEPL) of Real Tissue Samples for Validation of CT HU to Stopping Power Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R; Baer, E; Jee, K; Sharp, G; Flanz, J; Lu, H [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: For proton therapy, an accurate model of CT HU to relative stopping power (RSP) conversion is essential. In current practice, validation of these models relies solely on measurements of tissue substitutes with standard compositions. Validation based on real tissue samples would be much more direct and can address variations between patients. This study intends to develop an efficient and accurate system based on the concept of dose extinction to measure WEPL and retrieve RSP in biological tissue in large number of types. Methods: A broad AP proton beam delivering a spread out Bragg peak (SOBP) is used to irradiate the samples with a Matrixx detector positioned immediately below. A water tank was placed on top of the samples, with the water level controllable in sub-millimeter by a remotely controlled dosing pump. While gradually lowering the water level with beam on, the transmission dose was recorded at 1 frame/sec. The WEPL were determined as the difference between the known beam range of the delivered SOBP (80%) and the water level corresponding to 80% of measured dose profiles in time. A Gammex 467 phantom was used to test the system and various types of biological tissue was measured. Results: RSP for all Gammex inserts, expect the one made with lung-450 material (<2% error), were determined within ±0.5% error. Depends on the WEPL of investigated phantom, a measurement takes around 10 min, which can be accelerated by a faster pump. Conclusion: Based on the concept of dose extinction, a system was explored to measure WEPL efficiently and accurately for a large number of samples. This allows the validation of CT HU to stopping power conversions based on large number of samples and real tissues. It also allows the assessment of beam uncertainties due to variations over patients, which issue has never been sufficiently studied before.

  6. The time factor in dose-effect relationships

    International Nuclear Information System (INIS)

    Jones, H.B.; Grendon, A.; White, M.R.; California Univ., Berkeley

    1976-01-01

    The assumption that carcinogenic risk is proportional to dose fails to consider that probable time of actual cancer incidence. The time lag between exposure and carcinogenic effect for radiation and chemical agents varies as Dosesup(-1/n), with napproximately3. A model is offered explaining that concentration of initially altered cells depends on dose, whereas their chance for development into tumours on their proximity, which varies as Dsup(-1/3). Because of biological variability, n has a range of values. The model implies that tumours resulting from a single exposure should be closely distributed in time, producing a pulse of cases and subsequently being essentially without effect. Testing of the Dsup(-1/3) rule was extended and its model, by further refinement of methods, applied to radiogenic leukaemia risk and to the effect of urethan in inducing lung tumours in mice with and without radiation exposure as a possible cocarcinogen. Radiation did not affect the tumour yield from urethan in mice. Radiogenic leukaemia and lung tumours induced by urethan both occur in proportion to exposure, but the time of their occurrence is limited to a short interval in relation to life span. Similarly, in murine or in human radiogenic leukaemia, leukaemia risk occurs in proportion to exposure, but the time of occurrences is limited to a short interval in relation to life span. In both sets of observations, as well as in other test systems of carcinogenesis, the peak of occurrence or the mean latent period is roughly inversely related to Dsup(-1/3). Applied to lung tumours and leukaemia, the spread of cases about the peak incidence was found to be typically less than a fifth of the life span. Exposure risks do not continue to act over life span. Neoplastic disease risk from carcinogens levels too low to be tested experimentally, theoretically usually lies beyond the life span. The social and economic consequences of a theoretically calculated number of deaths due to those

  7. Rural settlements: social and ecological factors influencing on internal dose formation

    International Nuclear Information System (INIS)

    Visenberg, Yu.V; Vlasova, N.G.

    2008-01-01

    Full text: The aim of the present study is to reveal the reasons of difference in average internal doses in rural population living in the rural settlements situated on territories with equal levels of soil contamination; to show by clear examples that forming of internal dose is not only influenced directly by the contamination of the territory but also by number of factors of non-radiation origin. There were used data on internal doses as a result of WBC-measurements in rural inhabitants. Method of the study: there was applied the statistical analysis of the internal dose in rural population depending on the number of factors: radio-ecological represented by the transfer factor of radionuclides from soil to milk; environmental - closeness to the forest which, in its turn, determines intake of its resources by rural population; social - the number of population. There were selected settlements for the investigation whose residents had been WBC-measured for the period of 1990-2005's and their doses were evaluated. Thus, the conducted analysis shows that each of indirect (non-radiation) factors contributes in different way into formation of internal dose. The most significant of them is the social factor as follows from the results of the conducted analysis, represented by the number of inhabitants in a settlement. The internal dose depends not only on the level of contamination of the territory but also on the number of other factors: environmental, social, and radio-ecological. The influence of these factors on the process of dose formation in settlements should be considered simultaneously since neither of them is the leading one. Probably, there are other factors influencing on dose formation. Their investigation must be continued. (author)

  8. Depth dose factors for lymphoma's radiotherapy using a 4 MV linear accelerator

    International Nuclear Information System (INIS)

    Scaff, L.A.M.

    1976-01-01

    In the routine treatment of lymphomas using the mantle technique, the daily doses at the midpoints at five anatomical regions are different because their thickness are not equal. A set of tables of depht dose factors with good precision is presented [pt

  9. Exposure Scenarios and Unit Dose Factors for the Hanford Immobilized Low Activity Tank Waste Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    RITTMANN, P.D.

    1999-12-29

    Exposure scenarios are defined to identify potential pathways and combinations of pathways that could lead to radiation exposure from immobilized tank waste. Appropriate data and models are selected to permit calculation of dose factors for each exposure

  10. The "polyenviromic risk score": Aggregating environmental risk factors predicts conversion to psychosis in familial high-risk subjects.

    Science.gov (United States)

    Padmanabhan, Jaya L; Shah, Jai L; Tandon, Neeraj; Keshavan, Matcheri S

    2017-03-01

    Young relatives of individuals with schizophrenia (i.e. youth at familial high-risk, FHR) are at increased risk of developing psychotic disorders, and show higher rates of psychiatric symptoms, cognitive and neurobiological abnormalities than non-relatives. It is not known whether overall exposure to environmental risk factors increases risk of conversion to psychosis in FHR subjects. Subjects consisted of a pilot longitudinal sample of 83 young FHR subjects. As a proof of principle, we examined whether an aggregate score of exposure to environmental risk factors, which we term a 'polyenviromic risk score' (PERS), could predict conversion to psychosis. The PERS combines known environmental risk factors including cannabis use, urbanicity, season of birth, paternal age, obstetric and perinatal complications, and various types of childhood adversity, each weighted by its odds ratio for association with psychosis in the literature. A higher PERS was significantly associated with conversion to psychosis in young, familial high-risk subjects (OR=1.97, p=0.009). A model combining the PERS and clinical predictors had a sensitivity of 27% and specificity of 96%. An aggregate index of environmental risk may help predict conversion to psychosis in FHR subjects. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Evaluation of indoor radon equilibrium factor using CFD modeling and resulting annual effective dose

    Science.gov (United States)

    Rabi, R.; Oufni, L.

    2018-04-01

    The equilibrium factor is an important parameter for reasonably estimating the population dose from radon. However, the equilibrium factor value depended mainly on the ventilation rate and the meteorological factors. Therefore, this study focuses on investigating numerically the influence of the ventilation rate, temperature and humidity on equilibrium factor between radon and its progeny. The numerical results showed that ventilation rate, temperature and humidity have significant impacts on indoor equilibrium factor. The variations of equilibrium factor with the ventilation, temperature and relative humidity are discussed. Moreover, the committed equivalent doses due to 218Po and 214Po radon short-lived progeny were evaluated in different tissues of the respiratory tract of the members of the public from the inhalation of indoor air. The annual effective dose due to radon short lived progeny from the inhalation of indoor air by the members of the public was investigated.

  12. Risk of solid cancer in low dose-rate radiation epidemiological studies and the dose-rate effectiveness factor.

    Science.gov (United States)

    Shore, Roy; Walsh, Linda; Azizova, Tamara; Rühm, Werner

    2017-10-01

    Estimated radiation risks used for radiation protection purposes have been based primarily on the Life Span Study (LSS) of atomic bomb survivors who received brief exposures at high dose rates, many with high doses. Information is needed regarding radiation risks from low dose-rate (LDR) exposures to low linear-energy-transfer (low-LET) radiation. We conducted a meta-analysis of LDR epidemiologic studies that provide dose-response estimates of total solid cancer risk in adulthood in comparison to corresponding LSS risks, in order to estimate a dose rate effectiveness factor (DREF). We identified 22 LDR studies with dose-response risk estimates for solid cancer after minimizing information overlap. For each study, a parallel risk estimate was derived from the LSS risk model using matching values for sex, mean ages at first exposure and attained age, targeted cancer types, and accounting for type of dosimetric assessment. For each LDR study, a ratio of the excess relative risk per Gy (ERR Gy -1 ) to the matching LSS ERR risk estimate (LDR/LSS) was calculated, and a meta-analysis of the risk ratios was conducted. The reciprocal of the resultant risk ratio provided an estimate of the DREF. The meta-analysis showed a LDR/LSS risk ratio of 0.36 (95% confidence interval [CI] 0.14, 0.57) for the 19 studies of solid cancer mortality and 0.33 (95% CI 0.13, 0.54) when three cohorts with only incidence data also were added, implying a DREF with values around 3, but statistically compatible with 2. However, the analyses were highly dominated by the Mayak worker study. When the Mayak study was excluded the LDR/LSS risk ratios increased: 1.12 (95% CI 0.40, 1.84) for mortality and 0.54 (95% CI 0.09, 0.99) for mortality + incidence, implying a lower DREF in the range of 1-2. Meta-analyses that included only cohorts in which the mean dose was LDR data provide direct evidence regarding risk from exposures at low dose rates as an important complement to the LSS risk estimates used

  13. Time to sputum conversion in smear positive pulmonary TB patients on category I DOTS and factors delaying it.

    Science.gov (United States)

    Parikh, Raunak; Nataraj, Gita; Kanade, Swapna; Khatri, Vijay; Mehta, Preeti

    2012-08-01

    Sputum smear positive pulmonary tuberculosis patients expel infectious viable bacilli for a period following commencement of treatment. Patients on Directly Observed Treatment Shortcourse (DOTS) receive intermittent therapy with multidrug regimen. To determine the time to sputum smear and culture conversion following initiation of DOTS treatment and study the factors that influence it. A prospective study was undertaken at a tertiary care teaching hospital in Mumbai over a one year period on a cohort of 71 sputum smear positive patients on Category I DOTS treatment. Patients were followed up weekly for upto 20 weeks or until they underwent smear and culture conversion whichever was earlier. At each follow up, specimens were collected and processed for microscopy and culture using standard protocol. 60/71 [84.55%] patients completed the study. 56/60 [93.3%] patients underwent sputum smear and culture conversion. The median time to smear and culture conversion was end of 5th week [day 35] and 6 1/2 weeks [day 45] respectively. Univariate and stepwise regression analysis showed that patients who had cavitatory disease, high pretreatment smear grade and a past history of tuberculosis were more likely to undergo delayed or nonconversion [P culture conversion under DOTS is similar to previous antituberculosis regimens. Since viable bacilli continue to be expelled for upto two months, infection control measures should be maintained for such time. Patients with cavitatory disease, high pretreatment smear grade or a past history of tuberculosis need to be monitored more closely.

  14. Age-specific radiation dose commitment factors for a one-year chronic intake

    International Nuclear Information System (INIS)

    Hoenes, G.R.; Soldat, J.K.

    1977-11-01

    During the licensing process for nuclear facilities, radiation doses and dose commitments must be calculated for people in the environs of a nuclear facility. These radiation doses are determined by examining characteristics of population groups, pathways to people, and radionuclides found in those pathways. The pertinent characteristics, which are important in the sense of contributing a significant portion of the total dose, must then be analyzed in depth. Dose factors are generally available for adults, see Reference 1 for example, however numerous improvements in data on decay schemes and half-lives have been made in recent years. In addition, it is advisable to define parameters for calculation of the radiation dose for ages other than adults since the population surrounding nuclear facilities will be composed of various age groups. Further, since infants, children, and teens may have higher rates of intake per unit body mass, it is conceivable that the maximally exposed individual may not be an adult. Thus, it was necessary to develop new radiation-dose commitment factors for various age groups. Dose commitment factors presented in this report have been calculated for a 50-year time period for four age groups

  15. Attached, unattached fraction of progeny concentrations and equilibrium factor for dose assessments from {sup 222}Rn and {sup 220}Rn

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Parminder; Saini, Komal; Bajwa, Bikramjit Singh [Guru Nanak Dev University, Department of Physics, Amritsar, Punjab (India); Mishra, Rosaline; Sahoo, Bijay Kumar [Bhabha Atomic Research Centre, Radiological Physics and Advisory Division, Mumbai (India)

    2016-08-15

    In this study, measurements of indoor radon ({sup 222}Rn), thoron ({sup 220}Rn) and their equilibrium equivalent concentration (EEC) were carried out in 96 dwellings from 22 different villages situated in Hamirpur district, Himachal Pradesh, India, by using LR-115 type II-based pinhole twin cup dosimeters and deposition-based progeny sensors (DRPS/DTPS). The annual average indoor {sup 222}Rn and {sup 220}Rn concentrations observed in these dwellings were 63.82 and 89.59 Bq/m{sup 3}, respectively, while the average EEC (attached + unattached) for {sup 222}Rn and {sup 220}Rn was 29.28 and 2.74 Bq/m{sup 3}. For {sup 222}Rn (f{sub Rn}) and {sup 220}Rn (f{sub Tn}), the average values of unattached fraction were 0.11 and 0.09, respectively. The equilibrium factors for radon (F{sub Rn}) and thoron (F{sub Tn}) varied from 0.12 to 0.77 with an average of 0.50, and from 0.01 to 0.34 with an average of 0.05, respectively. The annual inhalation dose due to mouth and nasal breathing was calculated using dose conversion factors and unattached fractions. The indoor annual effective doses for {sup 222}Rn (AEDR) and {sup 220}Rn (AEDT) were found to be 1.92 and 0.83 mSv a{sup -1}, respectively. The values of {sup 222}Rn/{sup 220}Rn concentrations and annual effective doses obtained in the present study are within the safe limits as recommended by the International Commission on Radiological Protection for indoor dwelling exposure conditions. (orig.)

  16. Fluence-to-effective dose conversion coefficients from a Saudi population based phantom for monoenergetic photon beams from 10 keV to 20 MeV

    International Nuclear Information System (INIS)

    Ma, Andy K; Hussein, Mohammed Adel; Altaher, Khalid Mohammed; Farid, Khalid Yousif; Amer, Mamun; Aldhafery, Bander Fuhaid; Alghamdi, Ali A

    2015-01-01

    Fluence-to-dose conversion coefficients are important quantities for radiation protection, derived from Monte Carlo simulations of the radiation particles through a stylised phantom or voxel based phantoms. The voxel phantoms have been developed for many ethnic groups for their accurate reflection of the anatomy. In this study, we used the Monte Carlo code MCNPX to calculate the photon fluence-to-effective dose conversion coefficients with a voxel phantom based on the Saudi Arabian male population. Six irradiation geometries, anterior–posterior (AP), posterior–anterior (PA), left lateral (LLAT), right lateral (RLAT), rotational (ROT) and isotropic (ISO) were simulated for monoenergetic photon beams from 10 keV to 20 MeV. We compared the coefficients with the reference values in ICRP Publication 116. The coefficients in the AP and PA geometries match the reference values to 9% and 12% on average as measured by root mean square while those in the LLAT, RLAT ROT and ISO geometries differ, mostly below, from the reference by 23, 22, 15 and 16%, respectively. The torso of the Saudi phantom is wider than the ICRP reference male phantom and likely to cause more attenuation to the lateral beam. The ICRP reference coefficients serve well for the Saudi male population as conservative estimations for the purpose of radiation protection. (paper)

  17. The study of mean glandular dose in mammography in Yazd and the factors affecting it

    International Nuclear Information System (INIS)

    Bouzarjomehri, F.; Mostaar, A.; Ghasemi, A.; Ehramposh, M. H.; Khosravi, H.

    2006-01-01

    The objective of this study was to determine the mean glandular dose resulting from mammography examinations in Yazd, southeastern Iran and to identify the factors affecting it. Patients and Methods: This survey was conducted during May to December 2005 to estimate the mean glandular dose for women undergoing mammography and to report the distribution of dose. compressed breast thickness, glandular tissue content, and mammography technique used. The clinical data were collected from 946 mammograms taken from 246 women who were referred to four mammography centers. The mammography instruments in these centers were four modern units with a molybdenum anode and either molybdenum or rhodium filter. The exposure conditions of each mammogram were recorded. The breast glandular content of each mammogram was estimated by a radiologist. The mean glandular dose was calculated based on measuring the normalized entrance skin dose in air. half value layer, kVp, mAs, breast thickness and glandular content. Half value layer, kVp and entrance skin dose were measured by a solid-state detector. The analytical method of Sobol et al. was used for calculation of mean glandular dose . Results: The mean±SD mean glandular dose per film was.2±0.6 mGy for cranio caudal and 1.63±O.9 mGy for mediolateral oblique views. The mean±SD mean glandular dose per woman was 5.5 3.1.mGy. A positive correlation was found between the beam Half value layer with mean glandular dose (r=O.38) and the breast thickness with mean glandular dose (r=O.5). Conclusion: The mean±SD mean glandular dose per film of 1.42±0.8 mGy in present study was lower than most of similar reports. However, the mean mean glandular dose per woman was higher than that in other studies

  18. Role of different factors as preoperative predictors of conversion of laparoscopic cholecystectomy to open cholecystectomy

    Directory of Open Access Journals (Sweden)

    Ramlah Ghazanfar

    2017-01-01

    Full Text Available Aim: Laparoscopic cholecystectomy has become the gold standard for the treatment of gallstones. Background: The objective of our study was to identify the preoperative predictors of conversion of laparoscopic cholecystectomy into open cholecystectomy. Materials and Methods: We carried out a cross-sectional study in the Surgical Unit 1, Holy Family Hospital, Rawalpindi, from September 2016 to February 2017. All patients undergoing laparoscopic cholecystectomy were included in the study. Patients undergoing open cholecystectomy due to the presence of contraindication to laparoscopic cholecystectomy or patients in which laparoscopic cholecystectomy was a part of some other laparoscopic intervention were not included in the study. SPSS version 21 was used to analyze the data. Results: The overall mean age of the patients was 43.67 ± 13.54 years. The male patients were significantly older as compared to the female patients. The conversion rate was higher in patients who had an elevated total leukocyte count and alanine aminotransferase before the operation (P < 0.05. The rate of conversion was significantly higher in male patients aged ≥50 years (P < 0.05. Difficulty in the dissection of the triangle of Calot, difficulty in dissecting the gallbladder fossa, bleeding in gallbladder fossa, presence of duodenal fistula, and autolyzed gangrenous gallbladder were the reasons for the conversion to open cholecystectomy. Conclusion: The rate of conversion of laparoscopic cholecystectomy to open cholecystectomy was found to be 5%. Male patients aged ≥50 years, acalculous acute cholecystitis, acute cholecystitis, elevated preoperative total leukocyte count, and alanine aminotransferase levels were found to be significant predictors of conversion to open cholecystectomy.

  19. Conversion factor and uncertainty estimation for quantification of towed gamma-ray detector measurements in Tohoku coastal waters

    International Nuclear Information System (INIS)

    Ohnishi, S.; Thornton, B.; Kamada, S.; Hirao, Y.; Ura, T.; Odano, N.

    2016-01-01

    Factors to convert the count rate of a NaI(Tl) scintillation detector to the concentration of radioactive cesium in marine sediments are estimated for a towed gamma-ray detector system. The response of the detector against a unit concentration of radioactive cesium is calculated by Monte Carlo radiation transport simulation considering the vertical profile of radioactive material measured in core samples. The conversion factors are acquired by integrating the contribution of each layer and are normalized by the concentration in the surface sediment layer. At the same time, the uncertainty of the conversion factors are formulated and estimated. The combined standard uncertainty of the radioactive cesium concentration by the towed gamma-ray detector is around 25 percent. The values of uncertainty, often referred to as relative root mean squat errors in other works, between sediment core sampling measurements and towed detector measurements were 16 percent in the investigation made near the Abukuma River mouth and 5.2 percent in Sendai Bay, respectively. Most of the uncertainty is due to interpolation of the conversion factors between core samples and uncertainty of the detector's burial depth. The results of the towed measurements agree well with laboratory analysed sediment samples. Also, the concentrations of radioactive cesium at the intersection of each survey line are consistent. The consistency with sampling results and between different lines' transects demonstrate the availability and reproducibility of towed gamma-ray detector system.

  20. Conversion factor and uncertainty estimation for quantification of towed gamma-ray detector measurements in Tohoku coastal waters

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, S., E-mail: ohnishi@nmri.go.jp [National Maritime Research Institute, 6-38-1, Shinkawa, Mitaka, Tokyo 181-0004 (Japan); Thornton, B. [Institute of Industrial Science, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Kamada, S.; Hirao, Y.; Ura, T.; Odano, N. [National Maritime Research Institute, 6-38-1, Shinkawa, Mitaka, Tokyo 181-0004 (Japan)

    2016-05-21

    Factors to convert the count rate of a NaI(Tl) scintillation detector to the concentration of radioactive cesium in marine sediments are estimated for a towed gamma-ray detector system. The response of the detector against a unit concentration of radioactive cesium is calculated by Monte Carlo radiation transport simulation considering the vertical profile of radioactive material measured in core samples. The conversion factors are acquired by integrating the contribution of each layer and are normalized by the concentration in the surface sediment layer. At the same time, the uncertainty of the conversion factors are formulated and estimated. The combined standard uncertainty of the radioactive cesium concentration by the towed gamma-ray detector is around 25 percent. The values of uncertainty, often referred to as relative root mean squat errors in other works, between sediment core sampling measurements and towed detector measurements were 16 percent in the investigation made near the Abukuma River mouth and 5.2 percent in Sendai Bay, respectively. Most of the uncertainty is due to interpolation of the conversion factors between core samples and uncertainty of the detector's burial depth. The results of the towed measurements agree well with laboratory analysed sediment samples. Also, the concentrations of radioactive cesium at the intersection of each survey line are consistent. The consistency with sampling results and between different lines' transects demonstrate the availability and reproducibility of towed gamma-ray detector system.

  1. Structural and functional characterization of the product of disease-related factor H gene conversion.

    Science.gov (United States)

    Herbert, Andrew P; Kavanagh, David; Johansson, Conny; Morgan, Hugh P; Blaum, Bärbel S; Hannan, Jonathan P; Barlow, Paul N; Uhrín, Dušan

    2012-03-06

    Numerous complement factor H (FH) mutations predispose patients to atypical hemolytic uremic syndrome (aHUS) and other disorders arising from inadequately regulated complement activation. No unifying structural or mechanistic consequences have been ascribed to these mutants beyond impaired self-cell protection. The S1191L and V1197A mutations toward the C-terminus of FH, which occur in patients singly or together, arose from gene conversion between CFH encoding FH and CFHR1 encoding FH-related 1. We show that neither single nor double mutations structurally perturbed recombinant proteins consisting of the FH C-terminal modules, 19 and 20 (FH19-20), although all three FH19-20 mutants were poor, compared to wild-type FH19-20, at promoting hemolysis of C3b-coated erythrocytes through competition with full-length FH. Indeed, our new crystal structure of the S1191L mutant of FH19-20 complexed with an activation-specific complement fragment, C3d, was nearly identical to that of the wild-type FH19-20:C3d complex, consistent with mutants binding to C3b with wild-type-like affinity. The S1191L mutation enhanced thermal stability of module 20, whereas the V1197A mutation dramatically decreased it. Thus, although mutant proteins were folded at 37 °C, they differ in conformational rigidity. Neither single substitutions nor double substitutions increased measurably the extent of FH19-20 self-association, nor did these mutations significantly affect the affinity of FH19-20 for three glycosaminoglycans, despite critical roles of module 20 in recognizing polyanionic self-surface markers. Unexpectedly, FH19-20 mutants containing Leu1191 self-associated on a heparin-coated surface to a higher degree than on surfaces coated with dermatan or chondroitin sulfates. Thus, potentially disease-related functional distinctions between mutants, and between FH and FH-related 1, may manifest in the presence of specific glycosaminoglycans.

  2. 5 CFR Appendix A to Subpart C of... - Present Value Conversion Factors for Earlier Commencing Date of Annuities of Current and Former...

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Present Value Conversion Factors for Earlier Commencing Date of Annuities of Current and Former Spouses of Deceased Separated Employees A...—Present Value Conversion Factors for Earlier Commencing Date of Annuities of Current and Former Spouses of...

  3. SU-E-T-577: Obliquity Factor and Surface Dose in Proton Beam Therapy

    International Nuclear Information System (INIS)

    Das, I; Andersen, A; Coutinho, L

    2015-01-01

    Purpose: The advantage of lower skin dose in proton beam may be diminished creating radiation related sequalae usually seen with photon and electron beams. This study evaluates the surface dose as a complex function of beam parameters but more importantly the effect of beam angle. Methods: Surface dose in proton beam depends on the beam energy, source to surface distance, the air gap between snout and surface, field size, material thickness in front of surface, atomic number of the medium, beam angle and type of nozzle (ie double scattering, (DS), uniform scanning (US) or pencil beam scanning (PBS). Obliquity factor (OF) is defined as ratio of surface dose in 0° to beam angle Θ. Measurements were made in water phantom at various beam angles using very small microdiamond that has shown favorable beam characteristics for high, medium and low proton energy. Depth dose measurements were performed in the central axis of the beam in each respective gantry angle. Results: It is observed that surface dose is energy dependent but more predominantly on the SOBP. It is found that as SSD increases, surface dose decreases. In general, SSD, and air gap has limited impact in clinical proton range. High energy has higher surface dose and so the beam angle. The OF rises with beam angle. Compared to OF of 1.0 at 0° beam angle, the value is 1.5, 1.6, 1,7 for small, medium and large range respectively for 60 degree angle. Conclusion: It is advised that just like range and SOBP, surface dose should be clearly understood and a method to reduce the surface dose should be employed. Obliquity factor is a critical parameter that should be accounted in proton beam therapy and a perpendicular beam should be used to reduce surface dose

  4. Comparison of 3-Factor Prothrombin Complex Concentrate and Low-Dose Recombinant Factor VIIa for Warfarin Reversal

    OpenAIRE

    Chapman, Scott A; Irwin, Eric D; Abou-Karam, Nada M; Rupnow, Nichole M; Hutson, Katherine E; Vespa, Jeffrey; Roach, Robert M

    2014-01-01

    Introduction Prothrombin complex concentrate (PCC) and recombinant Factor VIIa (rFVIIa) have been used for emergent reversal of warfarin anticoagulation. Few clinical studies have compared these agents in warfarin reversal. We compared warfarin reversal in patients who received either 3 factor PCC (PCC3) or low-dose rFVIIa (LDrFVIIa) for reversal of warfarin anticoagulation. Methods Data were collected from medical charts of patients who received at least one dose of PCC3 (20 units/kg) or LDr...

  5. Quality factor and dose equivalent investigations aboard the Soviet Space Station Mir

    Science.gov (United States)

    Bouisset, P.; Nguyen, V. D.; Parmentier, N.; Akatov, Ia. A.; Arkhangel'Skii, V. V.; Vorozhtsov, A. S.; Petrov, V. M.; Kovalev, E. E.; Siegrist, M.

    1992-07-01

    Since Dec 1988, date of the French-Soviet joint space mission 'ARAGATZ', the CIRCE device, had recorded dose equivalent and quality factor values inside the Mir station (380-410 km, 51.5 deg). After the initial gas filling two years ago, the low pressure tissue equivalent proportional counter is still in good working conditions. Some results of three periods are presented. The average dose equivalent rates measured are respectively 0.6, 0.8 and 0.6 mSv/day with a quality factor equal to 1.9. Some detailed measurements show the increasing of the dose equivalent rates through the SAA and near polar horns. The real time determination of the quality factors allows to point out high linear energy transfer events with quality factors in the range 10-20.

  6. Real-world dose-relativity, tablet burden, and cost comparison of conversion between sevelamer hydrochloride/carbonate and lanthanum carbonate monotherapies.

    Science.gov (United States)

    Keith, Michael S; Sibbel, Scott; Copley, J Brian; Wilson, Rosamund J; Brunelli, Steven M

    2014-10-01

    Sevelamer hydrochloride/carbonate (SH/C) and lanthanum carbonate (LC) are noncalcium-based phosphate binders used for the management of hyperphosphatemia in patients with end-stage renal disease (ESRD). The objectives of this study were to examine the dose-relativity, tablet burden, and cost difference of bidirectional conversion between SH/C and LC monotherapy in a large cohort of real-world patients with ESRD. This retrospective cohort study included three 30-day preconversion periods (days -90 to -61, -60 to -31, and -30 to -1) followed by three 30-day postconversion periods (days 1 to 30, 31 to 60, and 61 to 90); day 0 was the index date of conversion. The full analysis population (FAP) comprised two cohorts: SH/C to LC (S-L) converters and LC to SH/C (L-S) converters. The SH/C:LC dose-relativity ratio was assessed in the dose-relativity subset, defined as patients whose serum phosphate levels fell within a caliper range of ± 0.5 mg/dL in the final preconversion (days -30 to -1) and postconversion (days 61 to 90) periods. Tablet burden and phosphate binder costs were assessed in the FAP. Phosphate binder costs were based on average wholesale prices. The FAP contained a total of 303 patients, comprising the S-L (128 patients) and L-S (175 patients) converter cohorts. The dose-relativity subset contained 159 patients, 72 from the S-L cohort and 87 from the L-S cohort. The overall mean SH/C:LC dose-relativity ratio was 2.27 (95% CI, 2.04 to 2.52). In SH/C dose strata >800 to 2400, >2400 to 4800, >4800 to 7200, and >7200 mg/d, overall mean dose-relativity ratios were 0.79 (95% CI, 0.57 to 1.10), 1.45 (95% CI, 1.20 to 1.75), 2.05 (95% CI, 1.75 to 2.39), and 3.24 (95% CI, 2.89 to 3.66), respectively. The overall mean tablet burden was 6.6 tablets per day lower with LC monotherapy than with SH/C monotherapy (95% CI, -7.1 to -6.0; P 7800 mg/d was the inflection point at which conversion to LC resulted in mean cost savings. Patients requiring SH/C >7800 mg/d comprised

  7. Conversion of Human Fibroblasts to Stably Self-Renewing Neural Stem Cells with a Single Zinc-Finger Transcription Factor

    Directory of Open Access Journals (Sweden)

    Ebrahim Shahbazi

    2016-04-01

    Full Text Available Direct conversion of somatic cells into neural stem cells (NSCs by defined factors holds great promise for mechanistic studies, drug screening, and potential cell therapies for different neurodegenerative diseases. Here, we report that a single zinc-finger transcription factor, Zfp521, is sufficient for direct conversion of human fibroblasts into long-term self-renewable and multipotent NSCs. In vitro, Zfp521-induced NSCs maintained their characteristics in the absence of exogenous factor expression and exhibited morphological, molecular, developmental, and functional properties that were similar to control NSCs. In addition, the single-seeded induced NSCs were able to form NSC colonies with efficiency comparable with control NSCs and expressed NSC markers. The converted cells were capable of surviving, migrating, and attaining neural phenotypes after transplantation into neonatal mouse and adult rat brains, without forming tumors. Moreover, the Zfp521-induced NSCs predominantly expressed rostral genes. Our results suggest a facilitated approach for establishing human NSCs through Zfp521-driven conversion of fibroblasts.

  8. Is the ICRP-26 weighting factor for gonadal dose appropriate for new federal regulations?

    International Nuclear Information System (INIS)

    Drum, D.E.

    1991-01-01

    In 1977 the ICRP recommended that computation of the occupational whole body effective dose equivalent include individual organ dose weighting factors derived from risk coefficients for stochastic effects. The-preeminent weighting factor of 0.25 was assigned to irradiation of the gonads in order to account for heritable genetic effects manifest in later generations. As of 1990, there exists no positive significant evidence for the occurrence of transmitted genetic effects in humans after radiation of any form, dose, or dose rate. To assign to gonads 25% of the health detriment from radiation has no basis in medical experience. It establishes a policy that may underestimate the proportion of real mortality from other more radiosensitive organs, and the policy could compromise unreasonably the occupational stability of workers whose activities may involve gonadal irradiation

  9. Probabilistic quantitative microbial risk assessment model of norovirus from wastewater irrigated vegetables in Ghana using genome copies and fecal indicator ratio conversion for estimating exposure dose

    DEFF Research Database (Denmark)

    Owusu-Ansah, Emmanuel de-Graft Johnson; Sampson, Angelina; Amponsah, Samuel K.

    2017-01-01

    physical and environmental factors that might influence the reliability of using indicator organisms in microbial risk assessment. The challenges facing analytical studies on virus enumeration (genome copies or particles) have contributed to the already existing lack of data in QMRA modelling. This study......The need to replace the commonly applied fecal indicator conversions ratio (an assumption of 1:10− 5 virus to fecal indicator organism) in Quantitative Microbial Risk Assessment (QMRA) with models based on quantitative data on the virus of interest has gained prominence due to the different...... attempts to fit a QMRA model to genome copies of norovirus data. The model estimates the risk of norovirus infection from the intake of vegetables irrigated with wastewater from different sources. The results were compared to the results of a corresponding model using the fecal indicator conversion ratio...

  10. Spectral correction factors for conventional neutron dose meters used in high-energy neutron environments improved and extended results based on a complete survey of all neutron spectra in IAEA-TRS-403

    International Nuclear Information System (INIS)

    Oparaji, U.; Tsai, Y. H.; Liu, Y. C.; Lee, K. W.; Patelli, E.; Sheu, R. J.

    2017-01-01

    This paper presents improved and extended results of our previous study on corrections for conventional neutron dose meters used in environments with high-energy neutrons (E n > 10 MeV). Conventional moderated-type neutron dose meters tend to underestimate the dose contribution of high-energy neutrons because of the opposite trends of dose conversion coefficients and detection efficiencies as the neutron energy increases. A practical correction scheme was proposed based on analysis of hundreds of neutron spectra in the IAEA-TRS-403 report. By comparing 252 Cf-calibrated dose responses with reference values derived from fluence-to-dose conversion coefficients, this study provides recommendations for neutron field characterization and the corresponding dose correction factors. Further sensitivity studies confirm the appropriateness of the proposed scheme and indicate that (1) the spectral correction factors are nearly independent of the selection of three commonly used calibration sources: 252 Cf, 241 Am-Be and 239 Pu-Be; (2) the derived correction factors for Bonner spheres of various sizes (6''-9'') are similar in trend and (3) practical high-energy neutron indexes based on measurements can be established to facilitate the application of these correction factors in workplaces. (authors)

  11. Assessment of independent risk factors of conversion into psychosis in the ultra-high risk state group of patients

    Directory of Open Access Journals (Sweden)

    Marta Gawłowska

    2010-12-01

    Full Text Available Background: The aim of this study was the independent psychosis risk factors assessment in a group of subjects fulfilling the criteria of at risk mental state, under specialist outpatient psychiatric care. Participants: Seventy-one patients – 33 women and 38 men, were involved into this study, aged on average 17.34, all under psychiatric care. The patients were recruited into the study in the sequence of their outpatient clinic admission. The criterion to be included into the study was the diagnosis of ultra-high risk state (UHRS – defined according to the Australian research group principles. Subsequently, the patients were divided into subgroups according to the clinical features of their mental state. Method: The author’s demographic questionnaire was applied in the study. Information regarding the family history of psychosis was obtained from patients and/or their relatives or carers. The patients’ mental state was assessed monthly – according to the presence of psychotic symptoms, change of their incidence and duration, presence of depressive symptoms or aggressive behaviour (measured by a three-level scale. On the basis of the obtained information, we evaluated: 1 conversion into psychosis time – measured from diagnosing of UHRS to the development of full-symptom psychosis, 2 therapeutic methods used (psychotherapy, pharmacotherapy or both, 3 use of psychoactive substances after being diagnosed with UHRS, 4 presence of serious life stressors (the patients’ subjective estimation – during the six-month period preceding the conversion into psychosis. Results: 1 In the UHRS group of patients, staying under professional outpatient psychiatric care, the use of marijuana was an independent risk factor of conversion into psychosis. 2 In the investigated group of patients with at risk mental state we did not find any correlation between modulating factors (including: therapeutic methods used, depressive symptoms, aggression or

  12. Dose and effect relationship of radiation induced cancer and its influencing factors in experimental animals, 1

    International Nuclear Information System (INIS)

    Sasaki, Shunsaku; Sato, Fumiaki; Eto, Hideo

    1975-01-01

    The data of risk evaluation of external irradiation were integrated with animal experiments from the aspects of qualitative generalizations of characteristics of radiation induced tumors. Studies covered competition of cause of death, figure of dose-to-effect relationship, characteristics of low dose rate of irradiation, relative biological effectiveness (RBE) of high LET radiation, effects of feactionated irradiation, complex actions with chemical substances, effects of protectional medium, differences of radiosensitivity by species and strains, and age dependency of sensitivities. Competition of cause of death by time length of latent period and degree of malignancy of the disease. Discussion on competition of death suggested the following idea: 1) incidence of tumor induction in the individual level did not correspond to transformation in the cellular level, and 2) relative incidence of tumor induction after a certain dose of whole body irradiation did not indicate the relative sensitivity of each tissue, for the relationship between tumor incidence and exposure dose was not a linear relationship. The dose-to-effect relationship of tumor induction was decided by following factors: i) sensitivity on transformation of cells, ii) sensitivity on the death of potential tumor cells, and iii) competition of the cause of death. Tumor induction by low dose rate irradiation was also studied by comparing qualitative and quantitative differences between high dose rate single irradiation and a series of low dose rate irradiation. (Serizawa, K.)

  13. Factors influencing success of metal to plastic conversion programs for under-hood applications

    Energy Technology Data Exchange (ETDEWEB)

    Male, L.J. [Amoco Chemicals Polymers Business Group, Alpharetta, GA (United States); Desai, K.C.

    1995-12-31

    This paper compares high performance engineering polymers available today for under-hood applications. It includes an example of an end cap showing value-added capabilities such as design for machining and assembly (DFMA), team approach and computer aided engineering being used for a most cost-effective custom molding solution. These techniques should be part of standard design procedure for conversion programs to cope with the challenges of today and tomorrow. (orig./HW)

  14. A graphical method for estimating the tunneling factor for mode conversion processes

    International Nuclear Information System (INIS)

    Swanson, D.G.

    1994-01-01

    The fundamental parameter characterizing the strength of any mode conversion process is the tunneling parameter, which is typically determined from a model dispersion relation which is transformed into a differential equation. Here a graphical method is described which gives the tunneling parameter from quantities directly measured from a simple graph of the dispersion relation. The accuracy of the estimate depends only on the accuracy of the measurements

  15. Development of a correction factor for Xe-133 vials for use with a dose calibrator

    International Nuclear Information System (INIS)

    Gels, G.L.; Piltingsrud, H.V.

    1982-01-01

    Manufacturers of dose calibrators who give calibration settings for various radionuclies sometimes do not specify the type of radionuclide container the calibration is for. The container, moreover, may not be of the same type as those a user might purchase. When these factors are not considered, the activity administered to the patient may be significantly different from that intended. An experiment is described in which calibration factors are determined for measurement of Xe-133 activity in vials in a dose calibrator. This was accomplished by transferring the Xe-133 from the commercial vials to standard NBS calibration ampules. Based on ten such transfers, the resulting correction factor for the dose calibrator was 1.22

  16. Age-specific inhalation radiation dose commitment factors for selected radionuclides

    International Nuclear Information System (INIS)

    Strenge, D.L.; Peloquin, R.A.; Baker, D.A.

    1982-08-01

    Inhalation dose commitment factors are presented for selected radionuclides for exposure of individuals in four age groups: infant, child, teen and adult. Radionuclides considered are 35 S, 36 Cl, 45 Ca, 67 Ga, 75 Se, 85 Sr, 109 Cd, 113 Sn, 125 I, 133 Ba, 170 Tm, 169 Yb, 182 Ta, 192 Ir, 198 Au, 201 Tl, 204 Tl, and 236 Pu. The calculational method is based on the human metabolic model of ICRP as defined in Publication 2 (ICRP 1959) and as used in previous age-specific dose factor calculations by Hoenes and Soldat (1977). Dose commitment factors are presented for the following organs of reference: total body, bone, liver, kidney, thyroid, lung and lower large intestine

  17. Determination of correction and conversion factor of exposure rate generated Gamma spectrometer GR-320 to Victoreen data

    International Nuclear Information System (INIS)

    Supardjo-AS; Mappa, Djody-Rachim; Nasrun-Syamsul; Syamsul-Hadi

    2000-01-01

    Exposure rate data of Muria Peninsula were generated from Victoreen-491 measurement and calculation of radioelement content in soil which were measured by Exploranium GR-320, using IAEA formula. However those data are not be comparable so the exposure rate calculated from Gamma Spectrometer data necessarily to be corrected. The correction factor was determinate by measuring the exposure rate of at the NMDC's back yard selected location using Victoreen-491 and Gamma Spectrometer Exploranium GR-320 . Correction factor was created by comparing mean exposure rate data that calculated from 30 data measured by Gamma Spectrometer instrument and to those Victoreen's exposure rate. Conversion factor was gained from comparing of total count data of Gamma Spectrometer Exploranium GR-320 to Victoreen's exposure rate data. The correction factor of Exploranium GR-320's exposure rate is 0.34 μR/hours, and the conversion factor of total count is 0.0092 μR/hours per c/m. Deviation Victoreen 491 = 4.7 % and Gamma Spectrometer Exploranium GR-320 8.6 %

  18. Low doses of cholera toxin and its mediator cAMP induce CTLA-2 secretion by dendritic cells to enhance regulatory T cell conversion.

    Directory of Open Access Journals (Sweden)

    Cinthia Silva-Vilches

    Full Text Available Immature or semi-mature dendritic cells (DCs represent tolerogenic maturation stages that can convert naive T cells into Foxp3+ induced regulatory T cells (iTreg. Here we found that murine bone marrow-derived DCs (BM-DCs treated with cholera toxin (CT matured by up-regulating MHC-II and costimulatory molecules using either high or low doses of CT (CThi, CTlo or with cAMP, a known mediator CT signals. However, all three conditions also induced mRNA of both isoforms of the tolerogenic molecule cytotoxic T lymphocyte antigen 2 (CTLA-2α and CTLA-2β. Only DCs matured under CThi conditions secreted IL-1β, IL-6 and IL-23 leading to the instruction of Th17 cell polarization. In contrast, CTlo- or cAMP-DCs resembled semi-mature DCs and enhanced TGF-β-dependent Foxp3+ iTreg conversion. iTreg conversion could be reduced using siRNA blocking of CTLA-2 and reversely, addition of recombinant CTLA-2α increased iTreg conversion in vitro. Injection of CTlo- or cAMP-DCs exerted MOG peptide-specific protective effects in experimental autoimmune encephalomyelitis (EAE by inducing Foxp3+ Tregs and reducing Th17 responses. Together, we identified CTLA-2 production by DCs as a novel tolerogenic mediator of TGF-β-mediated iTreg induction in vitro and in vivo. The CT-induced and cAMP-mediated up-regulation of CTLA-2 also may point to a novel immune evasion mechanism of Vibrio cholerae.

  19. Calculation of conversion coefficients of dose of a computational anthropomorphic simulator sit exposed to a plane source; Calculo de coeficientes de conversao de dose de um simulador antropomorfico computacional sentado exposto a uma fonte plana

    Energy Technology Data Exchange (ETDEWEB)

    Santos, William S.; Carvalho Junior, Alberico B. de; Pereira, Ariana J.S.; Santos, Marcos S.; Maia, Ana F., E-mail: williathan@yahoo.com.b, E-mail: ablohem@gmail.co, E-mail: ariana-jsp@hotmail.co, E-mail: m_souzasantos@hotmail.co, E-mail: afmaia@ufs.b [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil)

    2011-10-26

    In this paper conversion coefficients (CCs) of equivalent dose and effective in terms of kerma in the air were calculated suggested by the ICRP 74. These dose coefficients were calculated considering a plane radiation source and monoenergetic for a spectrum of energy varying from 10 keV to 2 MeV. The CCs were obtained for four geometries of irradiation, anterior-posterior, posterior-anterior, lateral right side and lateral left side. It was used the radiation transport code Visual Monte Carlo (VMC), and a anthropomorphic simulator of sit female voxel. The observed differences in the found values for the CCs at the four irradiation sceneries are direct results of the body organs disposition, and the distance of these organs to the irradiation source. The obtained CCs will be used for estimative more precise of dose in situations that the exposed individual be sit, as the normally the CCs available in the literature were calculated by using simulators always lying or on their feet

  20. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons; Desenvolvimento de uma metodologia para estimativa da dose absorvida e do poder de freamento para eletrons de conversao de baixa energia

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ivan Pedro Salati de

    1995-08-01

    The evaluation of absorbed dose in the case of external and internalcontamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy {sup 109} Cd conversion electrons, working with a 4 {pi} proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin {sup 109} Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  1. Thyroid Radiation Dose and Other Risk Factors of Thyroid Carcinoma Following Childhood Cancer.

    Science.gov (United States)

    de Vathaire, Florent; Haddy, Nadia; Allodji, Rodrigue S; Hawkins, Mike; Guibout, Catherine; El-Fayech, Chiraz; Teinturier, Cécile; Oberlin, Odile; Pacquement, Hélène; Diop, Fara; Kalhouche, Amar; Benadjaoud, Mohamedamine; Winter, David; Jackson, Angela; Bezin Mai-Quynh, Giao; Benabdennebi, Aymen; Llanas, Damien; Veres, Cristina; Munzer, Martine; Nguyen, Tan Dat; Bondiau, Pierre-Yves; Berchery, Delphine; Laprie, Anne; Deutsch, Eric; Lefkopoulos, Dimitri; Schlumberger, Martin; Diallo, Ibrahima; Rubino, Carole

    2015-11-01

    Thyroid carcinoma is a frequent complication of childhood cancer radiotherapy. The dose response to thyroid radiation dose is now well established, but the potential modifier effect of other factors requires additional investigation. This study aimed to investigate the role of potential modifiers of the dose response. We followed a cohort of 4338 5-year survivors of solid childhood cancer treated before 1986 over an average of 27 years. The dose received by the thyroid gland and some other anatomical sites during radiotherapy was estimated after reconstruction of the actual conditions in which irradiation was delivered. Fifty-five patients developed thyroid carcinoma. The risk of thyroid carcinoma increased with a radiation dose to the thyroid of up to two tenths of Gy, then leveled off for higher doses. When taking into account the thyroid radiation dose, a surgical or radiological splenectomy (>20 Gy to the spleen) increased thyroid cancer risk (relative risk [RR] = 2.3; 95% confidence interval [CI], 1.3-4.0), high radiation doses (>5 Gy) to pituitary gland lowered this risk (RR = 0.2; 95% CI, 0.1-0.6). Patients who received nitrosourea chemotherapy had a 6.6-fold (95% CI, 2.5-15.7) higher risk than those who did not. The excess RR per Gy of radiation to the thyroid was 4.7 (95% CI, 1.7-22.6). It was 7.6 (95% CI, 1.6-33.3) if body mass index at time of interview was equal or higher than 25 kg/m(2), and 4.1 (95% CI, 0.9-17.7) if not (P for interaction = .1). Predicting thyroid cancer risk following childhood cancer radiation therapy probably requires the assessment of more than just the radiation dose to the thyroid. Chemotherapy, splenectomy, radiation dose to pituitary gland, and obesity also play a role.

  2. Evaluation of fading factor and self-dose for glass dosimeter and thermoluminescence dosimeter

    International Nuclear Information System (INIS)

    Yamasaki, T.; Yamanishi, H.; Miyake, H.; Komura, K.

    2000-01-01

    The glass dosimeter (GD) and thermoluminescence dosimeter (TLD) are both passive radiation detectors. They are often used for measuring environmental radiation. In order to measure low dose rate preciously, it is important to evaluate decreased dose due to fading and self-dose during the exposure period. We evaluate the fading factor and self-dose of thee passive detectors, GD and TLD. We select Ogoya tunnel for the experiment. The tunnel is suitable field for measuring faded dose and self-dose because it is low cosmic radiation. At the center of the tunnel, the intensity of cosmic ray is reduced to about 1/177 than the outside of the funnel. We prepared two sets of dosimeters. One set consists of five GDs, five TLDs and some pre-irradiated GDs and TLDs that are exposed to standard radiation of 4 mGy by Cs-137. These dosimeters are put in the 10 cm thick lead box in order to shield the terrestrial gamma ray. One set is located at the center of the tunnel and the other is the outside of the funnel. The dosimeters were exposed for ten months, from May 1998 to March 1999. After the exposure, the readers of dosimeters are carried into the funnel to read out the signals promptly as soon as taking out the dosimeters. As a result of the measurement, four kinds of data are taken for GD and TLD respectively. Assumed that the self-dose and cosmic ray are constant during exposure, the four independent unknown quantities, a self-dose a dose due to cosmic ray and a fading coefficient at the center of the tunnel and at the outside, are considered. Therefore four simultaneous equations should be obtained. From these examinations, the faded dose of GD is less than 1%, but that of TLD is about 16% during ten months. The coefficient for compensation of fading of GD and TLD is given as the half of the each value. At the outside of the tunnel, the measured dose rate of cosmic ray that can pass through the 10 cm lead is evaluated to be about 16 nGy/h by both detectors. The self-dose

  3. T3 glottic cancer: an analysis of dose time-volume factors

    International Nuclear Information System (INIS)

    Harwood, A.R.; Beale, F.A.; Cummings, B.J.; Hawkins, N.V.; Keane, T.J.; Rider, W.D.

    1980-01-01

    This report analyzes dose-time-volume factors in 112 patients with T3N0M0 glottic cancer who were treated with radical radiotherapy with surgery for salvage between 1963 and 1977. 55% of the patients are alive and well 5 years following treatment; 26% died of glottic cancer and 19% died of intercurrent disease. In the 1965 to 1969 time period, 31% died of tumor as compared to 16% in the 1975 to 1977 time period. Overall local control by radiotherapy was 51%; 2/3 of the failures were surgically salvaged. 44% were locally controlled by radiotherapy in the 1965 to 1969 time period and 57% in the 1975 to 1977 time period. Analysis of dose-time-volume factors reveals that the optimal dose is greater than 1700 ret and a minimal volume of 6 x 8 cm should be used. A dose-cure curve for T3 glottic cancer is constructed and compared with the dose complication curve for the larynx and the dose-cure curve for T1N0M0 glottic cancer. A comparison of cure rates between 112 patients treated with radical radiotherapy and surgery for salvage versus 28 patients treated with combined pre-operative irradiation and surgery reveals no difference in the proportion of patients who died of glottic cancer or in the number of patients alive at 5 years following treatment

  4. Calculated dose factors for the radiosensitive tissues in bone irradiated by surface-deposited radionuclides

    International Nuclear Information System (INIS)

    Spiers, F.W.; Whitwell, J.R.; Beddoe, A.H.

    1978-01-01

    The method of calculating dose factors for the haemopoietic marrow and endosteal tissues in human trabecular bone, used by Whitwell and Spiers for volume-seeking radionuclides, has been developed for the case of radionuclides which are deposited as very thin layers on bone surfaces. The Monte Carlo method is again used, but modifications to the computer program are made to allow for a surface rather than a volume source of particle emission. The principal change is the introduction of a surface-orientation factor which is shown to have a value of approximately 2, varying slightly with bone structure. Results are given for β-emitting radionuclides ranging from 171 Tm(anti Esub(β) = 0.025 MeV) to 90 Y(anti Esub(β) = 0.93 MeV), and also for the α-emitter 239 Pu. It is shown that where the particle ranges are short compared with the dimensions of the bone structures the dose factors for the surface seekers are much greater than those for the volume seekers. For long range particles the dose factors for surface- and volume-seeking radionuclides converge. Comparisons are given relating the dose factors calculated in this paper on the basis of measured bone structures to those of other workers based on single plane geometry. (author)

  5. High-dose ascorbic acid decreases cholesterolemic factors of an atherogenic diet in guinea pigs.

    Science.gov (United States)

    Filis, Konstantinos; Anastassopoulou, Aikaterini; Sigala, Fragiska; Theodorou, Dimitrios; Manouras, Andreas; Leandros, Emanouel; Sigalas, Panagiotis; Hepp, Wolfgang; Bramis, John

    2007-03-01

    The study evaluates the effect of a high supplemental dose of ascorbic acid (AA) on plasma concentrations of total cholesterol (TC), triglycerides (TG), total lipids (TL), and lipoprotein fractions high-density, very-low-density-, and low-density lipoprotein (HDL, VLDL, LDL) in guinea pigs fed with atherogenic diet. Group I consisted of 5 normally fed guinea pigs plus a low dose of AA (1 mg/100 g/day), group II consisted of 7 guinea pigs fed with food enriched with 2% cholesterol plus a low dose of AA (1 mg/100 g/day), and group III consisted of 7 guinea pigs fed with food enriched with 2% cholesterol plus a high dose of AA (30 mg/100 g/day). Cholesterolemic factors concentrations were determined after nine weeks. Concentrations of TC, TG, TL, LDL, and VLDL were increased in group II compared to group I (p < 0.01 for all differences). Supplementation with a high dose of AA resulted in decreased concentrations of TC (p < 0.01), TG (p < 0.01), TL (p < 0.01), and LDL (p < 0.01) in group III compared to group II. Additionally, concentration of HDL was increased in group III compared to group II (p < 0.01). High-dose AA supplementation to an atherogenic diet decreases concentrations of TC, TG, TL, and LDL and increases concentration of HDL compared to low-dose AA.

  6. Adalimumab Dose Tapering in Psoriasis: Predictive Factors for Maintenance of Complete Clearance.

    Science.gov (United States)

    Hansel, Katharina; Bianchi, Leonardo; Lanza, Francesco; Bini, Vittorio; Stingeni, Luca

    2017-03-10

    Psoriasis can be managed successfully with long-term biologics. Real-life clinical practice may require dose tapering as a therapeutic option to reduce the risk of drug-exposure and to increase cost-effectiveness. The responsiveness to extended intervals between adalimumab doses and the possible predictive factors of maintenance of complete clearance were studied in a retrospective 7-year single-centre analysis. Thirty patients who achieved complete clearance with adalimumab underwent dose tapering, progressively extending between-dose intervals (to 21-28 days). Sixty percent of subjects (group A) maintained complete clearance, whereas 40.0% (group B) relapsed and were switched back to the standard dosage to re-achieve complete clearance. Body mass index (BMI) and time to achieve Psoriasis Area Severity Index (PASI-100) with adalimumab standard treatment before dose tapering were significantly lower in group A than in group B (multi-variate Cox regression: p < 0.05, Kaplan-Meier analysis: p < 0.001, respectively). This study suggests that patients with lower BMI and shorter time to achieve PASI-100 with adalimumab standard dose were significantly more likely to be candidates for dose tapering.

  7. Risk Factors and Dose-Effect Relationship for Mandibular Osteoradionecrosis in Oral and Oropharyngeal Cancer Patients

    International Nuclear Information System (INIS)

    Lee, Ik Jae; Koom, Woong Sub; Lee, Chang Geol; Kim, Yong Bae; Yoo, Sei Whan; Keum, Ki Chang; Kim, Gwi Eon; Choi, Eun Chang; Cha, In Ho

    2009-01-01

    Purpose: To analyze risk factors and the dose-effect relationship for osteoradionecrosis (ORN) of the mandible after radiotherapy of oral and oropharyngeal cancers. Materials and Methods: One-hundred ninety-eight patients with oral (45%) and oropharyngeal cancer (55%) who had received external radiotherapy between 1990 and 2000 were retrospectively reviewed. All patients had a dental evaluation before radiotherapy. The median radiation dose was 60 Gy (range, 16-75 Gy), and the median biologically effective dose for late effects (BED late ) in bone was 114 Gy 2 (range, 30-167 Gy 2 ). Results: The frequency of ORN was 13 patients (6.6%). Among patients with mandibular surgery, eight had ORN at the surgical site. Among patients without mandibular surgery, five patients had ORN on the molar area of the mandible. The median time to ORN was 22 months (range, 1-69 months). Univariate analysis revealed that mandibular surgery and Co-60 were significant risk factors for ORN (p = 0.01 and 0.04, respectively). In multivariate analysis, mandibular surgery was the most important factor (p = 0.001). High radiation doses over BED 102.6 Gy 2 (conventional dose of 54 Gy at 1.8 Gy/fraction) were also a significant factor for ORN (p = 0.008) and showed a positive dose-effect relationship in logistic regression (p = 0.04) for patients who had undergone mandibular surgery. Conclusions: Mandibular surgery was the most significant risk factor for ORN of mandible in oral and oropharyngeal cancers patients. A BED of 102.6 Gy 2 or higher to the mandible also significantly increases the risk of ORN.

  8. Factors Impacting the Conversion of Abstracts Presented at the Canadian Cardiovascular Congress Meetings to Full Publications

    DEFF Research Database (Denmark)

    Abuzeid, W.; Fosbøl, E.; Fosbøl, Philip Loldrup

    2013-01-01

    associated with transition of abstracts to full publications.BackgroundThe rate of conversion of abstracts presented at scientific meetings into peer reviewed published manuscripts, has been a topic of interest for various medical specialties. Rapid translation of abstracts into manuscripts allows...... for reliable and rapid communication of scientific knowledge into practice. Methods;Using a previously validated automated computer algorithm, we searched the ISI Web of Science to identify peer-reviewed full manuscript publications of abstracts presented at the CCC. We manually entered information about...

  9. Patient size and x-ray technique factors in head computed tomography examinations. I. Radiation doses

    International Nuclear Information System (INIS)

    Huda, Walter; Lieberman, Kristin A.; Chang, Jack; Roskopf, Marsha L.

    2004-01-01

    We investigated how patient age, size and composition, together with the choice of x-ray technique factors, affect radiation doses in head computed tomography (CT) examinations. Head size dimensions, cross-sectional areas, and mean Hounsfield unit (HU) values were obtained from head CT images of 127 patients. For radiation dosimetry purposes patients were modeled as uniform cylinders of water. Dose computations were performed for 18x7 mm sections, scanned at a constant 340 mAs, for x-ray tube voltages ranging from 80 to 140 kV. Values of mean section dose, energy imparted, and effective dose were computed for patients ranging from the newborn to adults. There was a rapid growth of head size over the first two years, followed by a more modest increase of head size until the age of 18 or so. Newborns have a mean HU value of about 50 that monotonically increases with age over the first two decades of life. Average adult A-P and lateral dimensions were 186±8 mm and 147±8 mm, respectively, with an average HU value of 209±40. An infant head was found to be equivalent to a water cylinder with a radius of ∼60 mm, whereas an adult head had an equivalent radius 50% greater. Adult males head dimensions are about 5% larger than for females, and their average x-ray attenuation is ∼20 HU greater. For adult examinations performed at 120 kV, typical values were 32 mGy for the mean section dose, 105 mJ for the total energy imparted, and 0.64 mSv for the effective dose. Increasing the x-ray tube voltage from 80 to 140 kV increases patient doses by about a factor of 5. For the same technique factors, mean section doses in infants are 35% higher than in adults. Energy imparted for adults is 50% higher than for infants, but infant effective doses are four times higher than for adults. CT doses need to take into account patient age, head size, and composition as well as the selected x-ray technique factors

  10. Factors affecting radiation doses from dedicated rail transport of spent reactor fuel

    International Nuclear Information System (INIS)

    Martin, J.E.

    1988-01-01

    This paper reports there are two exposure control concerns associated with the shipment of spent reactor fuel in dedicated trains -- compliance with transportation regulations for maximum allowable radiation levels, and minimizing the dose received by the general public. This article examines the methods used to calculate the dose equivalent rates alongside stationary (transport regulations) and moving trains (public exposure) of various lengths. The factors examined include the source term, the effect of overlapping radiation fields, the speed of the train, and the location of the population relative to the train. Trains made up of series of cars that individually meet transport regulations can, as a whole, exceed transport vehicle dose equivalent rate limits by up to 23% due to overlapping radiation fields. For moving trains and the worst case analyzed -- a person located 20 feet from the tracks and a train speed of 5 mph --- 141 rail cars would have to pass by to deliver a dose equivalent of 1 mrem

  11. Monte Carlo determination of the infinite matrix dose rate correction factors for 250 μm quartz and TLD500 chip

    International Nuclear Information System (INIS)

    Baly, L.; Martín, G.; Quesada, I.; Padilla, F.; Arteche, R.

    2015-01-01

    A new approach based on the Monte Carlo simulation is used to calculate the infinite matrix dose rate correction factors of gamma, beta and internal conversion radiations for 250 μm diameter grains of quartz and TLD500 chips. Here, the dependence of the correction factor on the radiation energy is initially calculated for each type of emitted particle and with this result the correction factors for the 232 Th and 238 U series and 40 K are determined. This analysis is made for dry soil and also for different levels of water content in it. The obtained beta correction factors for quartz are in good agreement with those previously reported. For the TLD500 chip certain differences with previously reported data are found. The analysis of the gamma water correction factor for quartz based on Zimmerman equation shows the correspondence with the similar correction factor for electrons. In the case of TLD500 chip a gamma water correction factor value of 1.0 was found. - Highlights: • A new approach based on Monte Carlo simulation is used to compute infinite matrix dose rate correction factors. • Infinite matrix models with real dimensions were analyzed within 3% uncertainties. • The dependence of grain size attenuation on particle energy is determined. • The same dependence for water correction factors is also analyzed

  12. Standardized dose factors for dose calculations - 1982 SRP reactor safety analysis report tritium, iodine, and noble gases

    International Nuclear Information System (INIS)

    Pillinger, W.L.; Marter, W.L.

    1982-01-01

    Standardized dose constants are recommended for calculation of offsite doses in the 1982 SRP Reactor Safety Analysis Report (SAR). Dose constants are proposed for inhalation of tritium and radioiodines and for submersion in a semi-infinite cloud of radioiodines and noble gases. The proposed constants, based on ICRP2 methodology for internal dose and methodology recommended by the US Nuclear Regulatory Commission for external dose, are compatible with dose calculational methods used at the Savannah River Plant and Savannah River Laboratory for normal releases of radioactivity. 8 references

  13. Fluence-to-dose conversion coefficients based on the posture modification of Adult Male (AM) and Adult Female (AF) reference phantoms of ICRP 110

    International Nuclear Information System (INIS)

    Galeano, D.C.; Santos, W.S.; Alves, M.C.; Souza, D.N.; Carvalho, A.B.

    2016-01-01

    The aim of this work was to modify the standing posture of the anthropomorphic reference phantoms of ICRP publication 110, AM (Adult Male) and AF (Adult Female), to the sitting posture. The change of posture was performed using the Visual Monte Carlo software (VMC) to rotate the thigh region of the phantoms and position it between the region of the leg and trunk. Scion Image software was used to reconstruct and smooth the knee and hip contours of the phantoms in a sitting posture. For 3D visualization of phantoms, the VolView software was used. In the change of postures, the organ and tissue masses were preserved. The MCNPX was used to calculate the equivalent and effective dose conversion coefficients (CCs) per fluence for photons for six irradiation geometries suggested by ICRP publication 110 (AP, PA, RLAT, LLAT, ROT and ISO) and energy range 0.010–10 MeV. The results were compared between the standing and sitting postures, for both sexes, in order to evaluate the differences of scattering and absorption of radiation for different postures. Significant differences in the CCs for equivalent dose were observed in the gonads, colon, prostate, urinary bladder and uterus, which are present in the pelvic region, and in organs distributed throughout the body, such as the lymphatic nodes, muscle, skeleton and skin, for the phantoms of both sexes. CCs for effective dose showed significant differences of up to 16% in the AP irradiation geometry, 27% in the PA irradiation geometry and 13% in the ROT irradiation geometry. These results demonstrate the importance of using phantoms in different postures in order to obtain more precise conversion coefficients for a given exposure scenario. - Highlights: • The reference phantoms AM and AF had modified its posture. • The AM and AF phantoms were irradiated in standing and sitting postures. • The irradiation geometry used were the AP, PA, LLAT, RLAT, ROT and ISO. • The CCs for standing and sitting postures were compared

  14. Main clinical, therapeutic and technical factors related to patient's maximum skin dose in interventional cardiology procedures

    Science.gov (United States)

    Journy, N; Sinno-Tellier, S; Maccia, C; Le Tertre, A; Pirard, P; Pagès, P; Eilstein, D; Donadieu, J; Bar, O

    2012-01-01

    Objective The study aimed to characterise the factors related to the X-ray dose delivered to the patient's skin during interventional cardiology procedures. Methods We studied 177 coronary angiographies (CAs) and/or percutaneous transluminal coronary angioplasties (PTCAs) carried out in a French clinic on the same radiography table. The clinical and therapeutic characteristics, and the technical parameters of the procedures, were collected. The dose area product (DAP) and the maximum skin dose (MSD) were measured by an ionisation chamber (Diamentor; Philips, Amsterdam, The Netherlands) and radiosensitive film (Gafchromic; International Specialty Products Advanced Materials Group, Wayne, NJ). Multivariate analyses were used to assess the effects of the factors of interest on dose. Results The mean MSD and DAP were respectively 389 mGy and 65 Gy cm−2 for CAs, and 916 mGy and 69 Gy cm−2 for PTCAs. For 8% of the procedures, the MSD exceeded 2 Gy. Although a linear relationship between the MSD and the DAP was observed for CAs (r=0.93), a simple extrapolation of such a model to PTCAs would lead to an inadequate assessment of the risk, especially for the highest dose values. For PTCAs, the body mass index, the therapeutic complexity, the fluoroscopy time and the number of cine frames were independent explanatory factors of the MSD, whoever the practitioner was. Moreover, the effect of technical factors such as collimation, cinematography settings and X-ray tube orientations on the DAP was shown. Conclusion Optimising the technical options for interventional procedures and training staff on radiation protection might notably reduce the dose and ultimately avoid patient skin lesions. PMID:22457404

  15. Choosing an alpha radiation weighting factor for doses to non-human biota

    International Nuclear Information System (INIS)

    Chambers, Douglas B.; Osborne, Richard V.; Garva, Amy L.

    2006-01-01

    The risk to non-human biota from exposure to ionizing radiation is of current international interest. In calculating radiation doses to humans, it is common to multiply the absorbed dose by a factor to account for the relative biological effectiveness (RBE) of the radiation type. However, there is no international consensus on the appropriate value of such a factor for weighting doses to non-human biota. This paper summarizes our review of the literature on experimentally determined RBEs for internally deposited alpha-emitting radionuclides. The relevancy of each experimental result in selecting a radiation weighting factor for doses from alpha particles in biota was judged on the basis of criteria established a priori. We recommend a nominal alpha radiation weighting factor of 5 for population-relevant deterministic and stochastic endpoints, but to reflect the limitations in the experimental data, uncertainty ranges of 1-10 and 1-20 were selected for population-relevant deterministic and stochastic endpoints, respectively

  16. Environmental factors used for the estimation of radiation dose to thyroid gland

    International Nuclear Information System (INIS)

    Ohmomo, Yoichiro

    1976-01-01

    Environmental factors used for the estimation of radiation dose to thyroid gland were discussed in this paper, such as deposition velocity of radioactive iodine onto plant leaves, elimination factor from the leaves, transfer of this nuclide to milk and the consumption of those critical foods especially by inhabitants around nuclear sites in coastal area of Ibaraki Prefecture. Uptake of the stable iodine was estimated. (auth.)

  17. Uncertainties in the correction factors as the dose polarization and recombination at different energies

    International Nuclear Information System (INIS)

    Alejo Luque, L.; Rodriguez Romero, R.; Castro Tejero, P.; Fandino Lareo, J. M.

    2011-01-01

    This paper discusses the measures and uncertainties of the correction factors for dose-polarization (k, 1) and recombination (k,) of different ionization chambers plane-parallel and cylindrical. The values ??have been obtained using photon and electron beams of various energies generated by linear accelerators nominal Varian 21EX CLJNAC Tomotherapy Hi-Art and JI. We study the cases in which you can avoid the application of the factors obtained, according to the criteria proposed

  18. Nitrogen-to-Protein Conversion Factors for Three Edible Insects: Tenebrio molitor, Alphitobius diaperinus, and Hermetia illucens.

    Science.gov (United States)

    Janssen, Renske H; Vincken, Jean-Paul; van den Broek, Lambertus A M; Fogliano, Vincenzo; Lakemond, Catriona M M

    2017-03-22

    Insects are considered a nutritionally valuable source of alternative proteins, and their efficient protein extraction is a prerequisite for large-scale use. The protein content is usually calculated from total nitrogen using the nitrogen-to-protein conversion factor (Kp) of 6.25. This factor overestimates the protein content, due to the presence of nonprotein nitrogen in insects. In this paper, a specific Kp of 4.76 ± 0.09 was calculated for larvae from Tenebrio molitor, Alphitobius diaperinus, and Hermetia illucens, using amino acid analysis. After protein extraction and purification, a Kp factor of 5.60 ± 0.39 was found for the larvae of three insect species studied. We propose to adopt these Kp values for determining protein content of insects to avoid overestimation of the protein content.

  19. Predictive Factors for Visual Field Conversion: Comparison of Scanning Laser Polarimetry and Optical Coherence Tomography.

    Science.gov (United States)

    Diekmann, Theresa; Schrems-Hoesl, Laura M; Mardin, Christian Y; Laemmer, Robert; Horn, Folkert K; Kruse, Friedrich E; Schrems, Wolfgang A

    2018-02-01

    The purpose of this study was to compare the ability of scanning laser polarimetry (SLP) and spectral-domain optical coherence tomography (SD-OCT) to predict future visual field conversion of subjects with ocular hypertension and early glaucoma. All patients were recruited from the Erlangen glaucoma registry and examined using standard automated perimetry, 24-hour intraocular pressure profile, and optic disc photography. Peripapillary retinal nerve fiber layer thickness (RNFL) measurements were obtained by SLP (GDx-VCC) and SD-OCT (Spectralis OCT). Positive and negative predictive values (PPV, NPV) were calculated for morphologic parameters of SLP and SD-OCT. Kaplan-Meier survival curves were plotted and log-rank tests were performed to compare the survival distributions. Contingency tables and Venn-diagrams were calculated to compare the predictive ability. The study included 207 patients-75 with ocular hypertension, 85 with early glaucoma, and 47 controls. Median follow-up was 4.5 years. A total of 29 patients (14.0%) developed visual field conversion during follow-up. SLP temporal-inferior RNFL [0.667; 95% confidence interval (CI), 0.281-0.935] and SD-OCT temporal-inferior RNFL (0.571; 95% CI, 0.317-0.802) achieved the highest PPV; nerve fiber indicator (0.923; 95% CI, 0.876-0.957) and SD-OCT mean (0.898; 95% CI, 0.847-0.937) achieved the highest NPV of all investigated parameters. The Kaplan-Meier curves confirmed significantly higher survival for subjects within normal limits of measurements of both devices (P<0.001). Venn diagrams tested with McNemar test statistics showed no significant difference for PPV (P=0.219) or NPV (P=0.678). Both GDx-VCC and SD-OCT demonstrate comparable results in predicting future visual field conversion if taking typical scans for GDx-VCC. In addition, the likelihood ratios suggest that GDx-VCC's nerve fiber indicator<30 may be the most useful parameter to confirm future nonconversion. (http://www.ClinicalTrials.gov number, NTC

  20. Prediction of the methane conversion factor (Ym) for dairy cows on the basis of national farm data

    DEFF Research Database (Denmark)

    Hellwing, Anne Louise Frydendahl; Weisbjerg, Martin Riis; Brask, Maike

    2016-01-01

    Methane constitutes a significant loss of feed gross energy in ruminants, and there is an ongoing struggle for identifying feed and animal characteristics feasible for documentation of National Greenhouse Gas Inventories. The aim of the current study was to develop a model that predicts the methane...... and feed composition as variables, and one using yield of energy corrected milk and feed composition as variables. The methane conversion factor was significantly reduced with increased content of starch and fat in the ration, whereas neutral detergent fibre content surprisingly did not have a significant...

  1. The calculation of relative output factor and depth dose for irregular electron fields in water

    International Nuclear Information System (INIS)

    Dunscombe, Peter; McGhee, Peter; Chu, Terence

    1996-01-01

    Purpose: A technique, based on sector integration and interpolation, has been developed for the computation of both relative output factor and depth dose of irregular electron fields in water. The purpose of this study was to determine the minimum experimental data set required for the technique to yield results within accepted dosimetric tolerances. Materials and Methods: PC based software has been written to perform the calculations necessary to dosimetrically characterize irregular shaped electron fields. The field outline is entered via digitiser and the SSD and energy via the keyboard. The irregular field is segmented into sectors of specified angle (2 deg. was used for this study) and the radius of each sector computed. The central ray depth dose is reconstructed by summing the contributions from each sector deduced from calibration depth doses measured for circular fields. Relative output factors and depth doses at SSDs at which calibrations were not performed are found by interpolation. Calibration data were measured for circular fields from 2 to 9 cm diameter at 100, 105, 110, and 115 cm SSD. A clinical cut out can be characterized in less than 2 minutes including entry of the outline using this software. The performance of the technique was evaluated by comparing calculated relative output factors, surface dose and the locations of d 80 , d 50 and d 20 with experimental measurements on a variety of cut out shapes at 9 and 18 MeV. The calibration data set (derived from circular cut outs) was systematically reduced to identify the minimum required to yield an accuracy consistent with current recommendations. Results: The figure illustrates the ability of the technique to calculate the depth dose for an irregular field (shown in the insert). It was found that to achieve an accuracy of 2% in relative output factor and 2% or 2 mm (our criterion) in percentage depth dose, calibration data from five circular fields at the four SSDs spanning the range 100-115 cm

  2. Dose-modifying factors for skin ulceration in mouse legs exposed to gamma rays

    International Nuclear Information System (INIS)

    Masuda, Kouji; Miyoshi, Makoto; Uehara, Satoru; Omagari, Junichi; Withers, H.R.

    1996-01-01

    To assess the dose-modifying factors for skin ulceration, the hind legs of mice were irradiated using gamma-rays of various doses in single exposures. The skin ulceration began to occur 2 months after irradiation, after early skin reactions such as wet desquamation, had healed completely. No new skin ulceration was observed more than 8 months after irradiation even though the observations were continued until 12 months post-irradiation. The ulceration dose 50 (UD50), a dose required to produce skin ulceration in from 2 to 8 months in 50% of the tested animals, was calculated for each treatment schedule. The preliminary shaving procedure reduced the UD50 dose to 0.85 that of the untreated controls. The ventral aspect of the hind leg was more radioresistant to single-dose irradiation than was to the dorsal aspect. The UD50 for the ventral aspect was 1.29 times that for the dorsal aspect when the skin had been previously shaved, and 1.46 times that for the unshaved control legs. The UD50 was 7 and 14% larger when mice were kept in the dorsal rather than the abdominal position during irradiation, for the preliminarily shaved and unshaved skin, respectively. (author)

  3. An engagement factor for caregiver radiation dose assessment with radioiodine treatment

    International Nuclear Information System (INIS)

    Lee, Hyun Kuk; Hong, Seong Jong; Jeong, Kyu Hwan; Jung, Jae Won; Kim, Seong Min; Kang, Yun-Hee; Han, Man Seok

    2015-01-01

    This study aims to suggest ways to better manage thyroid cancer patients treated with high- and low-activity radioiodine ( 131 I) by assessing external radiation doses to family members and caregivers and the level of radiation in the surrounding environment. The radiation doses to caregivers of 33 inpatients (who were quarantined in the hospital for 2-3 d after treatment) and 31 outpatients who received radioiodine treatment after thyroidectomy were measured using passive thermoluminescence dosemeters. In this study, 33 inpatients were administered high-activity (100-200 mCi) 131 I, and 31 outpatients were administered low-activity (30 mCi) 131 I. The average doses to caregivers were measured at 0.61 mSv for outpatients and 0.16 mSv for inpatients. The total integrated dose of the recovery (recuperation) rooms where the patients stayed after release from hospital was measured to be 0.83 mSv for outpatients and 0.23 mSv for inpatients. To reflect the degree of engagement between the caregiver and the patient, considering the duration and distance between two during exposure, the authors used the engagement factor introduced by Jeong et al. (Estimation of external radiation dose to caregivers of patients treated with radioiodine after thyroidectomy. Health Phys 2014;106:466-474.). This study presents a new engagement factor (K-value) of 0.82 obtained from the radiation doses to caregivers of both in- and out-patients treated with high- and low-activity radioiodine, and based on this new value, this study presented a new predicted dose for caregivers. A patient treated with high-activity radioiodine can be released after 24 h of isolation, whereas outpatients treated with low-activity radioiodine should be isolated for at least 12 h. (authors)

  4. Textiles: Some technocal information and data II: Conversion factors, fibre properties, spinning limits, typical twist factors, weaving performannce and transfer printing temperatures.

    CSIR Research Space (South Africa)

    Hunter, L

    1978-07-01

    Full Text Available OF THE CSIR P.O. B O X 1 1 2 4 P O R T E L I Z A B E T H R E P U B L I C O F S O U T H A F R I C A WOL 47 ISBN 0 7988 1360 1 Contents INTRODUCTION ........................................................... Page .; ... 1 CONVERSION FACTORSAND... ........................................................................................ 118 REFERENCES TEXTILES: SOME TECHNICAL INFORMATION AND DATA 11: CONVERSION FACTORS, FIBRE PROPERTIES, SPINNING L I M I T S , T Y P I C A L T W I S T F A C T O R S , W E A V I N G PERFORMANCE A N D TRANSFER PRINTING TEMPERATURES 6.5, L...

  5. Consideration of the ICRP 2006 revised tissue weighting factors on age-dependent values of the effective dose for external photons

    Science.gov (United States)

    Lee, Choonsik; Lee, Choonik; Han, Eun Young; Bolch, Wesley E.

    2007-01-01

    The effective dose recommended by the International Commission on Radiological Protection (ICRP) is the sum of organ equivalent doses weighted by corresponding tissue weighting factors, wT. ICRP is in the process of revising its 1990 recommendations on the effective dose where new values of organs and tissue weighting factors have been proposed and published in draft form for consultation by the radiological protection community. In its 5 June 2006 draft recommendations, new organs and tissues have been introduced in the effective dose which do not exist within the 1987 Oak Ridge National Laboratory (ORNL) phantom series (e.g., salivary glands). Recently, the investigators at University of Florida have updated the series of ORNL phantoms by implementing new organ models and adopting organ-specific elemental composition and densities. In this study, the effective dose changes caused by the transition from the current recommendation of ICRP Publication 60 to the 2006 draft recommendations were investigated for external photon irradiation across the range of ICRP reference ages (newborn, 1-year, 5-year, 10-year, 15-year and adult) and for six idealized irradiation geometries: anterior-posterior (AP), posterior-anterior (PA), left-lateral (LLAT), right-lateral (RLAT), rotational (ROT) and isotropic (ISO). Organ-absorbed doses were calculated by implementing the revised ORNL phantoms in the Monte Carlo radiation transport code, MCNPX2.5, after which effective doses were calculated under the 1990 and draft 2006 evaluation schemes of the ICRP. Effective doses calculated under the 2006 draft scheme were slightly higher than estimated under ICRP Publication 60 methods for all irradiation geometries exclusive of the AP geometry where an opposite trend was observed. The effective doses of the adult phantom were more greatly affected by the change in tissue weighting factors than that seen within the paediatric members of the phantom series. Additionally, dose conversion

  6. 76 FR 52539 - Federal Employees' Retirement System; Present Value Conversion Factors for Spouses of Deceased...

    Science.gov (United States)

    2011-08-23

    ... to revise the table of reduction factors for early commencing dates of survivor annuities for spouses... annuities, and to revise the annuity factor for spouses of deceased employees who die in service when those... precedence under 5 U.S.C. 8424, he or she may elect to receive the unexpended balance instead of an annuity...

  7. Total Ambient Dose Equivalent Buildup Factor Determination for Nbs04 Concrete.

    Science.gov (United States)

    Duckic, Paulina; Hayes, Robert B

    2018-06-01

    Buildup factors are dimensionless multiplicative factors required by the point kernel method to account for scattered radiation through a shielding material. The accuracy of the point kernel method is strongly affected by the correspondence of analyzed parameters to experimental configurations, which is attempted to be simplified here. The point kernel method has not been found to have widespread practical use for neutron shielding calculations due to the complex neutron transport behavior through shielding materials (i.e. the variety of interaction mechanisms that neutrons may undergo while traversing the shield) as well as non-linear neutron total cross section energy dependence. In this work, total ambient dose buildup factors for NBS04 concrete are calculated in terms of neutron and secondary gamma ray transmission factors. The neutron and secondary gamma ray transmission factors are calculated using MCNP6™ code with updated cross sections. Both transmission factors and buildup factors are given in a tabulated form. Practical use of neutron transmission and buildup factors warrants rigorously calculated results with all associated uncertainties. In this work, sensitivity analysis of neutron transmission factors and total buildup factors with varying water content has been conducted. The analysis showed significant impact of varying water content in concrete on both neutron transmission factors and total buildup factors. Finally, support vector regression, a machine learning technique, has been engaged to make a model based on the calculated data for calculation of the buildup factors. The developed model can predict most of the data with 20% relative error.

  8. Dose response and factors related to interstitial pneumonitis after bone marrow transplant

    International Nuclear Information System (INIS)

    Sampath, Sagus; Schultheiss, Timothy E.; Wong, Jeffrey

    2005-01-01

    Purpose: Total body irradiation (TBI) and chemotherapy are common components of conditioning regimens for bone marrow transplantation. Interstitial pneumonitis (IP) is a known regimen-related complication. Using published data of IP in a multivariate logistic regression, this study sought to identify the parameters in the bone marrow transplantation conditioning regimen that were significantly associated with IP and to establish a radiation dose-response function. Methods and Materials: A retrospective review was conducted of articles that reported IP incidence along with lung dose, fractionation, dose rate, and chemotherapy regimen. In the final analysis, 20 articles (n = 1090 patients), consisting of 26 distinct TBI/chemotherapy regimens, were included in the analysis. Multivariate logistic regression was performed to determine dosimetric and chemotherapeutic factors that influenced the incidence of IP. Results: A logistic model was generated from patients receiving daily fractions of radiation. In this model, lung dose, cyclophosphamide dose, and the addition of busulfan were significantly associated with IP. An incidence of 3%-4% with chemotherapy-only conditioning regimens is estimated from the models. The α/β value of the linear-quadratic model was estimated to be 2.8 Gy. The dose eliciting a 50% incidence, D 50 , for IP after 120 mg/kg of cyclophosphamide was 8.8 Gy; in the absence of chemotherapy, the estimated D 50 is 10.6 Gy. No dose rate effect was observed. The use of busulfan as a substitute for radiation is equivalent to treating with 14.8 Gy in 4 fractions with 50% transmission blocks shielding the lung. The logistic regression failed to find a model that adequately fit the multiple-fraction-per-day data. Conclusions: Dose responses for both lung radiation dose and cyclophosphamide dose were identified. A conditioning regimen of 12 Gy TBI in 6 daily fractions induces an IP incidence of about 11% in the absence of lung shielding. Shielding the lung

  9. Factors influencing completion of multi-dose vaccine schedules in adolescents: a systematic review

    Directory of Open Access Journals (Sweden)

    K. E. Gallagher

    2016-02-01

    Full Text Available Abstract Background Completion of multiple dose vaccine schedules is crucial to ensure a protective immune response, and maximise vaccine cost-effectiveness. While barriers and facilitators to vaccine uptake have recently been reviewed, there is no comprehensive review of factors influencing subsequent adherence or completion, which is key to achieving vaccine effectiveness. This study identifies and summarises the literature on factors affecting completion of multi-dose vaccine schedules by adolescents. Methods Ten online databases and four websites were searched (February 2014. Studies with analysis of factors predicting completion of multi-dose vaccines were included. Study participants within 9–19 years of age were included in the review. The defined outcome was completion of the vaccine series within 1 year among those who received the first dose. Results Overall, 6159 abstracts were screened, and 502 full texts were reviewed. Sixty one studies were eligible for this review. All except two were set in high-income countries. Included studies evaluated human papillomavirus vaccine, hepatitis A, hepatitis B, and varicella vaccines. Reported vaccine completion rates, among those who initiated vaccination, ranged from 27 % to over 90 %. Minority racial or ethnic groups and inadequate health insurance coverage were risk factors for low completion, irrespective of initiation rates. Parental healthcare seeking behaviour was positively associated with completion. Vaccine delivery in schools was associated with higher completion than delivery in the community or health facilities. Gender, prior healthcare use and socio-economic status rarely remained significant risks or protective factors in multivariate analysis. Conclusions Almost all studies investigating factors affecting completion have been carried out in developed countries and investigate a limited range of variables. Increased understanding of barriers to completion in adolescents will

  10. Tank Z-361 dose rate calculations

    International Nuclear Information System (INIS)

    Richard, R.F.

    1998-01-01

    Neutron and gamma ray dose rates were calculated above and around the 6-inch riser of tank Z-361 located at the Plutonium Finishing Plant. Dose rates were also determined off of one side of the tank. The largest dose rate 0.029 mrem/h was a gamma ray dose and occurred 76.2 cm (30 in.) directly above the open riser. All other dose rates were negligible. The ANSI/ANS 1991 flux to dose conversion factor for neutrons and photons were used in this analysis. Dose rates are reported in units of mrem/h with the calculated uncertainty shown within the parentheses

  11. Measurement with total scatter calibrate factor at different depths in the calculation of prescription dose

    International Nuclear Information System (INIS)

    Li Lijun; Zhu Haijun; Zhang Xinzhong; Li Feizhou; Song Hongyu

    2004-01-01

    Objective: To evaluate the method of measurement of total scatter calibrate factor (Sc, p). Methods: To measure the Sc, p at different depths on central axis of 6MV, 15MV photon beams through different ways. Results: It was found that the measured data of Sc, p changed with the different depths to a range of 1% - 7%. Using the direct method, the Sc, p measured depth should be the same as the depth in dose normalization point of the prescription dose. If the Sc, p (fsz, d) was measured at the other depths, it could be obtained indirectly by the calculation formula. Conclusions: The Sc, p in the prescription dose can be obtained either by the direct measure method or the indirect calculation formula. But emphasis should be laid on the proper measure depth. (authors)

  12. Quantitative investigation of physical factors contributing to gold nanoparticle-mediated proton dose enhancement

    International Nuclear Information System (INIS)

    Cho, Jongmin; Manohar, Nivedh; Kerr, Matthew; Cho, Sang Hyun; Gonzalez-Lepera, Carlos; Krishnan, Sunil

    2016-01-01

    Some investigators have shown tumor cell killing enhancement in vitro and tumor regression in mice associated with the loading of gold nanoparticles (GNPs) before proton treatments. Several Monte Carlo (MC) investigations have also demonstrated GNP-mediated proton dose enhancement. However, further studies need to be done to quantify the individual physical factors that contribute to the dose enhancement or cell-kill enhancement (or radiosensitization). Thus, the current study investigated the contributions of particle-induced x-ray emission (PIXE), particle-induced gamma-ray emission (PIGE), Auger and secondary electrons, and activation products towards the total dose enhancement. Specifically, GNP-mediated dose enhancement was measured using strips of radiochromic film that were inserted into vials of cylindrical GNPs, i.e. gold nanorods (GNRs), dispersed in a saline solution (0.3 mg of GNRs/g or 0.03% of GNRs by weight), as well as vials containing water only, before proton irradiation. MC simulations were also performed with the tool for particle simulation code using the film measurement setup. Additionally, a high-purity germanium detector system was used to measure the photon spectrum originating from activation products created from the interaction of protons and spherical GNPs present in a saline solution (20 mg of GNPs/g or 2% of GNPs by weight). The dose enhancement due to PIXE/PIGE recorded on the films in the GNR-loaded saline solution was less than the experimental uncertainty of the film dosimetry (<2%). MC simulations showed highly localized dose enhancement (up to a factor 17) in the immediate vicinity (<100 nm) of GNRs, compared with hypothetical water nanorods (WNRs), mostly due to GNR-originated Auger/secondary electrons; however, the average dose enhancement over the entire GNR-loaded vial was found to be minimal (0.1%). The dose enhancement due to the activation products from GNPs was minimal (<0.1%) as well. In conclusion, under the

  13. Concord Grape Juice Polyphenols and Cardiovascular Risk Factors: Dose-Response Relationships

    Science.gov (United States)

    Blumberg, Jeffrey B.; Vita, Joseph A.; Chen, C. -Y. Oliver

    2015-01-01

    Pure fruit juices provide nutritional value with evidence suggesting some of their benefits on biomarkers of cardiovascular disease risk may be derived from their constituent polyphenols, particularly flavonoids. However, few data from clinical trials are available on the dose-response relationship of fruit juice flavonoids to these outcomes. Utilizing the results of clinical trials testing single doses, we have analyzed data from studies of 100% Concord grape juice by placing its flavonoid content in the context of results from randomized clinical trials of other polyphenol-rich foods and beverages describing the same outcomes but covering a broader range of intake. We selected established biomarkers determined by similar methods for measuring flow-mediated vasodilation (FMD), blood pressure, platelet aggregation, and the resistance of low density lipoprotein cholesterol (LDL) to oxidation. Despite differences among the clinical trials in the treatment, subjects, and duration, correlations were observed between the dose and FMD. Inverse dose-response relationships, albeit with lower correlation coefficients, were also noted for the other outcomes. These results suggest a clear relationship between consumption of even modest serving sizes of Concord grape juice, flavonoid intake, and effects on risk factors for cardiovascular disease. This approach to dose-response relationships may prove useful for testing other individual foods and beverages. PMID:26633488

  14. Evaluation of dose attenuation factor of armored car against radiation accidents

    International Nuclear Information System (INIS)

    Sato, Tatsuhiko; Fujii, Katsutoshi; Murayama, Takashi

    2002-03-01

    The Tokyo Fire Department developed an armored car against radiation accidents. The car is covered by lead shields for attenuating dose from gamma rays. Dose from neutrons also can be attenuated by pouring water into tanks attached to the surface of the car. However, dose attenuation factors of the radiation shields had been determined by an estimation of single-layer shield, and more precise evaluation of multi-layer shield was required. By request from the Tokyo Fire Department, a precise evaluation of the dose attenuation in multi-layer shield was carried out. The evaluation was made by a Monte Carlo radiation transport simulation code MCNP4B for the shields used in the front, side and back of the car. Three types of the radiation sources ( 252 Cf as a neutron source, 60 Co as a gamma ray source, and radiation source corresponding to the JCO criticality accident) were considered in the calculation. Benchmark experiments using neutron and gamma ray sources were also performed for ensuring the evaluation method. As a result, it was found out that doses of neutron and gamma ray were attenuated to approximately 10% and 25% by the thickest shield, respectively. These values were close to the ones which had already obtained by the estimation of single-layer shield. (author)

  15. Risk factors for failed conversion of labor epidural analgesia to cesarean delivery anesthesia: a systematic review and meta-analysis of observational trials.

    Science.gov (United States)

    Bauer, M E; Kountanis, J A; Tsen, L C; Greenfield, M L; Mhyre, J M

    2012-10-01

    This systematic review and meta-analysis evaluates evidence for seven risk factors associated with failed conversion of labor epidural analgesia to cesarean delivery anesthesia. Online scientific literature databases were searched using a strategy which identified observational trials, published between January 1979 and May 2011, which evaluated risk factors for failed conversion of epidural analgesia to anesthesia or documented a failure rate resulting in general anesthesia. 1450 trials were screened, and 13 trials were included for review (n=8628). Three factors increase the risk for failed conversion: an increasing number of clinician-administered boluses during labor (OR=3.2, 95% CI 1.8-5.5), greater urgency for cesarean delivery (OR=40.4, 95% CI 8.8-186), and a non-obstetric anesthesiologist providing care (OR=4.6, 95% CI 1.8-11.5). Insufficient evidence is available to support combined spinal-epidural versus standard epidural techniques, duration of epidural analgesia, cervical dilation at the time of epidural placement, and body mass index or weight as risk factors for failed epidural conversion. The risk of failed conversion of labor epidural analgesia to anesthesia is increased with an increasing number of boluses administered during labor, an enhanced urgency for cesarean delivery, and care being provided by a non-obstetric anesthesiologist. Further high-quality studies are needed to evaluate the many potential risk factors associated with failed conversion of labor epidural analgesia to anesthesia for cesarean delivery. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. DOSE COEFFICIENTS FOR LIVER CHEMOEMBOLISATION PROCEDURES USING MONTE CARLO CODE.

    Science.gov (United States)

    Karavasilis, E; Dimitriadis, A; Gonis, H; Pappas, P; Georgiou, E; Yakoumakis, E

    2016-12-01

    The aim of the present study is the estimation of radiation burden during liver chemoembolisation procedures. Organ dose and effective dose conversion factors, normalised to dose-area product (DAP), were estimated for chemoembolisation procedures using a Monte Carlo transport code in conjunction with an adult mathematical phantom. Exposure data from 32 patients were used to determine the exposure projections for the simulations. Equivalent organ (H T ) and effective (E) doses were estimated using individual DAP values. The organs receiving the highest amount of doses during these exams were lumbar spine, liver and kidneys. The mean effective dose conversion factor was 1.4 Sv Gy -1 m -2 Dose conversion factors can be useful for patient-specific radiation burden during chemoembolisation procedures. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Treatment plan modification using voxel-based weighting factors/dose prescription

    International Nuclear Information System (INIS)

    Wu Chuan; Olivera, Gustavo H; Jeraj, Robert; Keller, Harry; Mackie, Thomas R

    2003-01-01

    Under various clinical situations, it is desirable to modify the original treatment plan to better suit the clinical goals. In this work, a method to help physicians modify treatment plans based on their clinical preferences is proposed. The method uses a weighted quadratic dose objective function. The commonly used organ-/ROI-based weighting factors are expanded to a set of voxel-based weighting factors in order to obtain greater flexibility in treatment plan modification. Two different but equivalent modification schemes based on Rustem's quadratic programming algorithms -modification of a weighting matrix and modification of prescribed doses - are presented. Case studies demonstrated the effectiveness of the two methods with regard to their capability to fine-tune treatment plans

  18. Direct conversion of human fibroblasts into functional osteoblasts by defined factors.

    Science.gov (United States)

    Yamamoto, Kenta; Kishida, Tsunao; Sato, Yoshiki; Nishioka, Keisuke; Ejima, Akika; Fujiwara, Hiroyoshi; Kubo, Toshikazu; Yamamoto, Toshiro; Kanamura, Narisato; Mazda, Osam

    2015-05-12

    Osteoblasts produce calcified bone matrix and contribute to bone formation and remodeling. In this study, we established a procedure to directly convert human fibroblasts into osteoblasts by transducing some defined factors and culturing in osteogenic medium. Osteoblast-specific transcription factors, Runt-related transcription factor 2 (Runx2), and Osterix, in combination with Octamer-binding transcription factor 3/4 (Oct4) and L-Myc (RXOL) transduction, converted ∼ 80% of the fibroblasts into osteocalcin-producing cells. The directly converted osteoblasts (dOBs) induced by RXOL displayed a similar gene expression profile as normal human osteoblasts and contributed to bone repair after transplantation into immunodeficient mice at artificial bone defect lesions. The dOBs expressed endogenous Runx2 and Osterix, and did not require continuous expression of the exogenous genes to maintain their phenotype. Another combination, Oct4 plus L-Myc (OL), also induced fibroblasts to produce bone matrix, but the OL-transduced cells did not express Osterix and exhibited a more distant gene expression profile to osteoblasts compared with RXOL-transduced cells. These findings strongly suggest successful direct reprogramming of fibroblasts into functional osteoblasts by RXOL, a technology that may provide bone regeneration therapy against bone disorders.

  19. Monthly Rainfall Erosivity: Conversion Factors for Different Time Resolutions and Regional Assessments

    DEFF Research Database (Denmark)

    Panagos, Panos; Borrelli, Pasquale; Spinoni, Jonathan

    2016-01-01

    , for the optimization of land management (seasonal variation of vegetation cover and agricultural support practices) as well as natural hazard protection (landslides and flood prediction). We expanded REDES by 140 rainfall stations, thus covering areas where monthly R-factor values were missing (Slovakia, Poland...

  20. THE METALLICITY DEPENDENCE OF THE CO {yields} H{sub 2} CONVERSION FACTOR IN z {>=} 1 STAR-FORMING GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Genzel, R.; Tacconi, L. J.; Schreiber, N. M. Foerster; Gracia-Carpio, J.; Lutz, D.; Saintonge, A. [Max-Planck-Institut fuer extraterrestrische Physik (MPE), Giessenbachstr. 1, 85748 Garching (Germany); Combes, F. [Observatoire de Paris, LERMA, CNRS, 61 Av. de l' Observatoire, F-75014 Paris (France); Bolatto, A. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Neri, R.; Cox, P. [IRAM, 300 Rue de la Piscine, 38406 St. Martin d' Heres, Grenoble (France); Sternberg, A. [Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Cooper, M. C. [Department of Physics and Astronomy, Frederick Reines Hall, University of California, Irvine, CA 92697-4575 (United States); Bouche, N. [Department of Physics, University of California, Santa Barbara, Broida Hall, Santa Barbara, CA 93106 (United States); Bournaud, F. [Service d' Astrophysique, DAPNIA, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex (France); Burkert, A. [Universitaetssternwarte der Ludwig-Maximiliansuniversitaet, Scheinerstr. 1, D-81679 Muenchen (Germany); Comerford, J. [Department of Astronomy and McDonald Observatory, 1 University Station, C1402 Austin, TX 78712-0259 (United States); Davis, M.; Newman, S. [Department of Astronomy, Campbell Hall, University of California, Berkeley, CA 94720 (United States); Garcia-Burillo, S. [Observatorio Astronomico Nacional-OAN, Apartado 1143, 28800 Alcala de Henares- Madrid (Spain); Naab, T., E-mail: genzel@mpe.mpg.de, E-mail: linda@mpe.mpg.de [Max-Planck Institut fuer Astrophysik (MPA), Karl Schwarzschildstrasse 1, D-85748 Garching (Germany); and others

    2012-02-10

    We use the first systematic samples of CO millimeter emission in z {>=} 1 'main-sequence' star-forming galaxies to study the metallicity dependence of the conversion factor {alpha}{sub CO,} from CO line luminosity to molecular gas mass. The molecular gas depletion rate inferred from the ratio of the star formation rate (SFR) to CO luminosity, is {approx}1 Gyr{sup -1} for near-solar metallicity galaxies with stellar masses above M{sub S} {approx} 10{sup 11} M{sub Sun }. In this regime, the depletion rate does not vary more than a factor of two to three as a function of molecular gas surface density or redshift between z {approx} 0 and 2. Below M{sub S} the depletion rate increases rapidly with decreasing metallicity. We argue that this trend is not caused by starburst events, by changes in the physical parameters of the molecular clouds, or by the impact of the fundamental-metallicity-SFR-stellar mass relation. A more probable explanation is that the conversion factor is metallicity dependent and that star formation can occur in 'CO-dark' gas. The trend is also expected theoretically from the effect of enhanced photodissociation of CO by ultraviolet radiation at low metallicity. From the available z {approx} 0 and z {approx} 1-3 samples we constrain the slope of the log({alpha}{sub CO})-log (metallicity) relation to range between -1 and -2, fairly insensitive to the assumed slope of the gas-SFR relation. Because of the lower metallicities near the peak of the galaxy formation activity at z {approx} 1-2 compared to z {approx} 0, we suggest that molecular gas masses estimated from CO luminosities have to be substantially corrected upward for galaxies below M{sub S}.

  1. Analysis of the risk factors for exposure of the lung to low irradiation doses

    International Nuclear Information System (INIS)

    Hogeweg, B.

    1986-02-01

    In this report a description is presented of the risk factors for induction of lungtumours. The contribution of natural radioactivity from uranium and thorium to the lungs is mainly caused by inhalation of alpha-emitting radon and thorium daughter products. Apart from exposure by inhalation the lungs are also exposed to external radiation. For internal as well as external exposure a value of 10 -3 lungcancers per Sv lung dose equivalence is found to be acceptable for the riskfactor. (Auth.)

  2. Calibration of megavoltage cone-beam CT for radiotherapy dose calculations: Correction of cupping artifacts and conversion of CT numbers to electron density

    International Nuclear Information System (INIS)

    Petit, Steven F.; Elmpt, Wouter J. C. van; Nijsten, Sebastiaan M. J. J. G.; Lambin, Philippe; Dekker, Andre L. A. J.

    2008-01-01

    Megavoltage cone-beam CT (MV CBCT) is used for three-dimensional imaging of the patient anatomy on the treatment table prior to or just after radiotherapy treatment. To use MV CBCT images for radiotherapy dose calculation purposes, reliable electron density (ED) distributions are needed. Patient scatter, beam hardening and softening effects result in cupping artifacts in MV CBCT images and distort the CT number to ED conversion. A method based on transmission images is presented to correct for these effects without using prior knowledge of the object's geometry. The scatter distribution originating from the patient is calculated with pencil beam scatter kernels that are fitted based on transmission measurements. The radiological thickness is extracted from the scatter subtracted transmission images and is then converted to the primary transmission used in the cone-beam reconstruction. These corrections are performed in an iterative manner, without using prior knowledge regarding the geometry and composition of the object. The method was tested using various homogeneous and inhomogeneous phantoms with varying shapes and compositions, including a phantom with different electron density inserts, phantoms with large density variations, and an anthropomorphic head phantom. For all phantoms, the cupping artifact was substantially removed from the images and a linear relation between the CT number and electron density was found. After correction the deviations in reconstructed ED from the true values were reduced from up to 0.30 ED units to 0.03 for the majority of the phantoms; the residual difference is equal to the amount of noise in the images. The ED distributions were evaluated in terms of absolute dose calculation accuracy for homogeneous cylinders of different size; errors decreased from 7% to below 1% in the center of the objects for the uncorrected and corrected images, respectively, and maximum differences were reduced from 17% to 2%, respectively. The

  3. Intraoperative use of low-dose recombinant activated factor VII during thoracic aortic operations.

    Science.gov (United States)

    Andersen, Nicholas D; Bhattacharya, Syamal D; Williams, Judson B; Fosbol, Emil L; Lockhart, Evelyn L; Patel, Mayur B; Gaca, Jeffrey G; Welsby, Ian J; Hughes, G Chad

    2012-06-01

    Numerous studies have supported the effectiveness of recombinant activated factor VII (rFVIIa) for the control of bleeding after cardiac procedures; however safety concerns persist. Here we report the novel use of intraoperative low-dose rFVIIa in thoracic aortic operations, a strategy intended to improve safety by minimizing rFVIIa exposure. Between July 2005 and December 2010, 425 consecutive patients at a single referral center underwent thoracic aortic operations with cardiopulmonary bypass (CPB); 77 of these patients received intraoperative low-dose rFVIIa (≤60 μg/kg) for severe coagulopathy after CPB. Propensity matching produced a cohort of 88 patients (44 received intraoperative low-dose rFVIIa and 44 controls) for comparison. Matched patients receiving intraoperative low-dose rFVIIa got an initial median dose of 32 μg/kg (interquartile range [IQR], 16-43 μg/kg) rFVIIa given 51 minutes (42-67 minutes) after separation from CPB. Patients receiving intraoperative low-dose rFVIIa demonstrated improved postoperative coagulation measurements (partial thromboplastin time 28.6 versus 31.5 seconds; p=0.05; international normalized ratio, 0.8 versus 1.2; pproduct transfusions (2.5 versus 5.0 units; p=0.05) compared with control patients. No patient receiving intraoperative low-dose rFVIIa required postoperative rFVIIa administration or reexploration for bleeding. Rates of stroke, thromboembolism, myocardial infarction, and other adverse events were equivalent between groups. Intraoperative low-dose rFVIIa led to improved postoperative hemostasis with no apparent increase in adverse events. Intraoperative rFVIIa administration in appropriately selected patients may correct coagulopathy early in the course of refractory blood loss and lead to improved safety through the use of smaller rFVIIa doses. Appropriately powered randomized studies are necessary to confirm the safety and efficacy of this approach. Copyright © 2012 The Society of Thoracic Surgeons

  4. Importance of radiation time and dose factors on outcome for childhood medulloblastoma

    International Nuclear Information System (INIS)

    Back, M.; Barton, M.

    2005-01-01

    The purpose of this study was to investigate the relationship of posterior fossa radiation therapy duration (PFRTD) and relapse-free survival (RFS) following adjuvant craniospinal RT for childhood medulloblastoma. A retrospective audit was performed assessing all children aged 180days) pre-RT chemotherapy were excluded. Data were obtained for potential prognostic factors in domains of patient, tumour and treatment factors. Radiation therapy time factors assessed were PFRTD and time interval from surgery to commencement of RT (SRTD). The end-point assessed was RFS and analysis was performed using Cox regression and Kaplan-Meier survival. One hundred and eighty-nine children were identified from 10 oncology units, with data available from 182 children for analysis. Median follow up was 5.3 years. Seventy-three per cent of children presented with disease confined to the cerebellum; 13% had initial neuraxis disease. Macroscopic resection was described in 54%; 42% received adjuvant chemotherapy. Median RT dose and RT duration to PF was 55 Gy and 45 days, respectively. Seventy-eight relapses occurred with a 10-year actuarial RFS of 58.2% (standard error±4%). On univariate analysis, increasing PF dose (P = 0.002), age >5 years (P 0.006), and more thorough extent of surgical resection (P - 0.043) were associated with improved RFS; PFRTD (P = 0.20) and SRTD (P = 0.51) were not associated with RFS. On multivariate analysis, although both PF dose (P 0.004) and extent of surgery (P = 0.045) remained strongly significant, RT duration was now associated with RFS (P = 0.049). Other factors assessed that did not reach significance were patient age, local tumour extent, presence of internal shunt and use of chemotherapy. The importance of local treatment factors was confirmed in this audit with established prognostic factors such as primary tumour macroscopic resection and adequate PF RT dose being associated with RFS. A treatment time effect is weakly suggested, although less

  5. Prognostic factors of inoperable localized lung cancer treated by high dose radiotherapy

    International Nuclear Information System (INIS)

    Schaake-Koning, C.S.; Schuster-Uitterhoeve, L.; Hart, G.; Gonzalez, D.G.

    1983-01-01

    A retrospective study was made of the results of high dose radiotherapy (greater than or equal to 50 Gy) given to 171 patients with inoperable, intrathoracic non small cell lung cancer from January 1971-April 1973. Local control was dependent on the total tumor dose: after one year local control was 63% for patients treated with >65 Gy, the two year local control was 35%. If treated with 2 , the one year local control was 72%; the two year local control was 44%. Local control was also influenced by the performance status, by the localization of the primary tumor in the left upper lobe and in the periphery of the lung. Local control for tumors in the left upper lobe and in the periphery of the lung was about 70% after one year, and about 40% after two years. The one and two years survival results were correlated with the factors influencing local control. The dose factor, the localization factors and the performance influenced local control independently. Tumors localized in the left upper lobe did metastasize less than tumors in the lower lobe, or in a combination of the two. This was not true for the right upper lobe. No correlation between the TNM system, pathology and the prognosis was found

  6. Method and apparatus to provide power conversion with high power factor

    Energy Technology Data Exchange (ETDEWEB)

    Perreault, David J.; Lim, Seungbum; Otten, David M.

    2017-05-23

    A power converter circuit rectifies a line voltage and applies the rectified voltage to a stack of capacitors. Voltages on the capacitors are coupled to a plurality of regulating converters to be converted to regulated output signals. The regulated output signals are combined and converted to a desired DC output voltage of the power converter. Input currents of the regulating converters are modulated in a manner that enhances the power factor of the power converter.

  7. Fluence-to-absorbed-dose conversion coefficients for neutron beams from 0.001 eV to 100 GeV calculated for a set of pregnant female and fetus models

    International Nuclear Information System (INIS)

    Taranenko, Valery; Xu, X George

    2008-01-01

    Protection of fetuses against external neutron exposure is an important task. This paper reports a set of absorbed dose conversion coefficients for fetal and maternal organs for external neutron beams using the RPI-P pregnant female models and the MCNPX code. The newly developed pregnant female models represent an adult female with a fetus including its brain and skeleton at the end of each trimester. The organ masses were adjusted to match the reference values within 1%. For the 3 mm cubic voxel size, the models consist of 10-15 million voxels for 35 organs. External monoenergetic neutron beams of six standard configurations (AP, PA, LLAT, RLAT, ROT and ISO) and source energies 0.001 eV-100 GeV were considered. The results are compared with previous data that are based on simplified anatomical models. The differences in dose depend on source geometry, energy and gestation periods: from 20% up to 140% for the whole fetus, and up to 100% for the fetal brain. Anatomical differences are primarily responsible for the discrepancies in the organ doses. For the first time, the dependence of mother organ doses upon anatomical changes during pregnancy was studied. A maximum of 220% increase in dose was observed for the placenta in the nine months model compared to three months, whereas dose to the pancreas, small and large intestines decreases by 60% for the AP source for the same models. Tabulated dose conversion coefficients for the fetus and 27 maternal organs are provided

  8. Opportunities to improve the conversion of food waste to lactate: Fine-tuning secondary factors.

    Science.gov (United States)

    RedCorn, Raymond; Engelberth, Abigail S

    2017-11-01

    Extensive research has demonstrated the potential for bioconversion of food waste to lactate, with major emphasis on adjusting temperature, pH, and loading rate of the fermentation. Each of these factors has a significant effect on lactate production; however, additional secondary factors have received little attention. Here we investigate three additional factors where opportunities exist for process improvement: freezing of samples during storage, discontinuous pH control, and holdover of fermentation broth between fermentations. Freezing samples prior to fermentation was shown to reduce the production rate of lactate by 8%, indicating freeze-thaw should be avoided in experiments. Prior work indicated a trade-off in pH control strategies, where discontinuous pH control correlated with higher lactate accumulation while continuous pH control correlated with higher production rate. Here we demonstrate that continuous pH control can achieve both higher lactate accumulation and higher production rate. Finally, holding over fermentation broth was shown to be a simple method to improve production rate (by 18%) at high food waste loading rates (>140 g volatile solids L -1 ) but resulted in lower lactate accumulation (by 17%). The results inform continued process improvements within the waste treatment of food waste through fermentation to lactic acid.

  9. Estimated fluence-to-absorbed dose conversion coefficients for use in radiological protection of embryo and foetus against external exposure to photons from 50 keV to 10 GeV

    International Nuclear Information System (INIS)

    Chen, J.

    2006-01-01

    In the literature, no conversion coefficients are available for use in radiological protection of the embryo and foetus against external exposure to photons. This study used the Monte-Carlo code MCNPX to determine mean absorbed doses to the embryo and foetus when the mother is exposed to external photon fields. Monoenergetic photons ranging from 50 keV to 10 GeV were considered. The irradiation geometries included antero-posterior (AP), postero-anterior (PA), lateral (LAT), rotational (ROT), and isotropic (ISO). At each of these standard irradiation geometries, absorbed doses to the foetal brain and body were calculated for the embryo of 8 weeks and the foetus of 3, 6 or 9 months. Photon fluence-to-absorbed-dose conversion coefficients were estimated for the four prenatal ages. (authors)

  10. Fluence-to-absorbed dose conversion coefficients for use in radiological protection of embryo and foetus against external exposure to protons from 100 MeV to 100 GeV

    International Nuclear Information System (INIS)

    Chen, J.

    2006-01-01

    In the literature, no conversion coefficients are available for use in radiological protection of embryo and foetus against external exposure to protons. This study used the Monte Carlo code MCNPX to determine mean absorbed doses to the embryo and foetus when the mother is exposed to proton fields. Monoenergetic protons ranging from 100 MeV to 100 GeV were considered. The irradiation geometries include antero-posterior (AP), postero-anterior (PA), lateral (LAT), rotational (ROT) and isotropic (ISO). At each of these standard irradiation geometries, absorbed doses to the foetal brain and body were calculated for the embryo of 8 weeks and the foetus of 3, 6 or 9 months. Proton fluence-to-absorbed dose conversion coefficients were derived for the four prenatal ages. (authors)

  11. Fluence-to-Absorbed Dose Conversion Coefficients for Use in Radiological Protection of Embryo and Foetus Against External Exposure to Muons from 20MeV to 50GeV

    International Nuclear Information System (INIS)

    Chen Jing

    2008-01-01

    This study used the Monte-Carlo code MCNPX to determine mean absorbed doses to the embryo and foetus when the mother is exposed to external muon fields. Monoenergetic muons ranging from 20 MeV to 50 GeV were considered. The irradiation geometries include anteroposterior (AP), postero-anterior (PA), lateral (LAT), rotational (ROT), isotropic (ISO), and top-down (TOP). At each of these irradiation geometries, absorbed doses to the foetal body were calculated for the embryo of 8 weeks and the foetus of 3, 6 or 9 months, respectively. Muon fluence-to-absorbed-dose conversion coefficients were derived for the four prenatal ages. Since such conversion coefficients are yet unknown, the results presented here fill a data gap

  12. High-dose anti-histamine use and risk factors in children with urticaria.

    Science.gov (United States)

    Uysal, Pınar; Avcil, Sibelnur; Erge, Duygu

    2016-12-01

    The drugs of choice in the treatment of urticaria in children are H1-antihistamines. The aim of the study was to evaluate children with urticaria and define risk factors for requirement of high-dose H1-antihistamines in children with urticaria. The medical data of children who were diagnosed as having urticaria admitted to our outpatient clinic between January 2014 and January 2016 were searched. The medical histories, concomitant atopic diseases, parental atopy histories, medications, treatment responses, blood eosinophil and basophil counts, and serum total IgE levels were recorded. In addition, the urticaria activity score for seven days, autoimmune antibody tests, and skin prick test results were evaluated in children with chronic urticaria. The numbers of the children with acute and chronic urticaria were 138 and 92, respectively. The age of the children with chronic urticaria was higher than that of those with acute urticaria (p0.05). There was a negative correlation between blood eosinophil count and the UAS7 score in children with chronic urticaria (r=-0.276, p=0.011). Chronic urticaria and requirement of high dose H1-antihistamines were significant in children aged ≥10 years (p<0.001, p=0.015). High UAS7 score (OR: 1.09; CI 95%: [1.03-1.15]) and basopenia (OR: 6.77; CI 95%: [2.01-22.75]) were associated with the requirement of high-dose H1-AH in children with chronic urticaria. The requirement of high-dose H1-antihistamines was higher with children's increasing age. Disease severity and basopenia were risk factors for the requirement of high-dose H1-antihistamines.

  13. Pluripotent Conversion of Muscle Stem Cells Without Reprogramming Factors or Small Molecules.

    Science.gov (United States)

    Bose, Bipasha; Shenoy P, Sudheer

    2016-02-01

    Muscle derived stem cells (MDSCs) are multipotent stem cells that can differentiate into several lineages including skeletal muscle precursor cells. Here, we show that MDSCs from myostatin null mice (Mstn (-/-) ) can be readily induced into pluripotent stem cells without using reprogramming factors. Microarray studies revealed a strong upregulation of markers like Leukemia Inhibitory factor (LIF) and Leukemia Inhibitory factor receptor (LIFR) in Mstn (-/-) MDSCs as compared to wild type MDSCs (WT-MDSCs). Furthermore when cultured in mouse embryonic stem cell media with LIF for 95 days, Mstn (-/-) MDSCs formed embryonic stem cell (ES) like colonies. We termed such ES like cells as the culture-induced pluripotent stem cells (CiPSC). CiPSCs from Mstn (-/-) MDSCs were phenotypically similar to ESCs, expressed high levels of Oct4, Nanog, Sox2 and SSEA-1, maintained a normal karyotype. Furthermore, CiPSCs formed embryoid bodies and teratomas when injected into immunocompromised mice. In addition, CiPSCs differentiated into somatic cells of all three lineages. We further show that culturing in ES cell media, resulted in hypermethylation and downregulation of BMP2 in Mstn(-/-) MDSCs. Western blot further confirmed a down regulation of BMP2 signaling in Mstn (-/-) MDSCs in supportive of pluripotent reprogramming. Given that down regulation of BMP2 has been shown to induce pluripotency in cells, we propose that lack of myostatin epigenetically reprograms the MDSCs to become pluripotent stem cells. Thus, here we report the successful establishment of ES-like cells from adult stem cells of the non-germline origin under culture-induced conditions without introducing reprogramming genes.

  14. Environmentally Printing Efficient Organic Tandem Solar Cells with High Fill Factors: A Guideline Towards 20% Power Conversion Efficiency

    DEFF Research Database (Denmark)

    Li, Ning; Baran, Derya; Spyropoulos, George D.

    2014-01-01

    presents a major challenge. The reported high PCE values from lab-scale spin-coated devices are, of course, representative, but not helpful for commercialization. Here, organic tandem solar cells with exceptionally high fill factors and PCE values of 7.66% (on glass) and 5.56% (on flexible substrate...... to enhance the power conversion efficiency (PCE). However, due to the undeveloped deposition techniques, the challenges in ink formulation as well as the lack of commercially available high performance active materials, roll-to-roll fabrication of highly efficient organic tandem solar cells currently......), which are the highest values for the solution-processed tandem solar cells fabricated by a mass-production compatible coating technique under ambient conditions, are demonstrated. To predict the highest possible performance of tandem solar cells, optical simulation based on experimentally feasible...

  15. Identification and Characterization of Soluble Factors Involved in Delayed Effects of Low Dose Radiation. Final report

    International Nuclear Information System (INIS)

    Baulch, Janet

    2013-01-01

    This is a 'glue grant' that was part of a DOE Low Dose project entitled 'Identification and Characterization of Soluble Factors Involved in Delayed Effects of Low Dose Radiation'. This collaborative program has involved Drs. David L. Springer from Pacific Northwest National Laboratory (PNNL), John H. Miller from Washington State University, Tri-cities (WSU) and William F. Morgan then from the University of Maryland, Baltimore (UMB). In July 2008, Dr. Morgan moved to PNNL and Dr. Janet E. Baulch became PI for this project at University of Maryland. In November of 2008, a one year extension with no new funds was requested to complete the proteomic analyses. The project stemmed from studies in the Morgan laboratory demonstrating that genomically unstable cells secret a soluble factor or factors into the culture medium, that cause cytogenetic aberrations and apoptosis in normal parental GM10115 cells. The purpose of this project was to identify the death inducing effect (DIE) factor or factors, estimate their relative abundance, identify the cell signaling pathways involved and finally recapitulate DIE in normal cells by exogenous manipulation of putative DIE factors in culture medium. As reported in detail in the previous progress report, analysis of culture medium from the parental cell line, and stable and unstable clones demonstrated inconsistent proteomic profiles as relate to candidate DIE factors. While the proposed proteomic analyses did not provide information that would allow DIE factors to be identified, the analyses provided another important set of observations. Proteomic analysis suggested that proteins associated with the cellular response to oxidative stress and mitochondrial function were elevated in the medium from unstable clones in a manner consistent with mitochondrial dysfunction. These findings correlate with previous studies of these clones that demonstrated functional differences between the mitochondria of stable and unstable clones. These

  16. Identification and Characterization of Soluble Factors Involved in Delayed Effects of Low Dose Radiation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Baulch, Janet

    2013-09-11

    This is a 'glue grant' that was part of a DOE Low Dose project entitled 'Identification and Characterization of Soluble Factors Involved in Delayed Effects of Low Dose Radiation'. This collaborative program has involved Drs. David L. Springer from Pacific Northwest National Laboratory (PNNL), John H. Miller from Washington State University, Tri-cities (WSU) and William F. Morgan then from the University of Maryland, Baltimore (UMB). In July 2008, Dr. Morgan moved to PNNL and Dr. Janet E. Baulch became PI for this project at University of Maryland. In November of 2008, a one year extension with no new funds was requested to complete the proteomic analyses. The project stemmed from studies in the Morgan laboratory demonstrating that genomically unstable cells secret a soluble factor or factors into the culture medium, that cause cytogenetic aberrations and apoptosis in normal parental GM10115 cells. The purpose of this project was to identify the death inducing effect (DIE) factor or factors, estimate their relative abundance, identify the cell signaling pathways involved and finally recapitulate DIE in normal cells by exogenous manipulation of putative DIE factors in culture medium. As reported in detail in the previous progress report, analysis of culture medium from the parental cell line, and stable and unstable clones demonstrated inconsistent proteomic profiles as relate to candidate DIE factors. While the proposed proteomic analyses did not provide information that would allow DIE factors to be identified, the analyses provided another important set of observations. Proteomic analysis suggested that proteins associated with the cellular response to oxidative stress and mitochondrial function were elevated in the medium from unstable clones in a manner consistent with mitochondrial dysfunction. These findings correlate with previous studies of these clones that demonstrated functional differences between the mitochondria of stable and

  17. The Story of Serum Prothrombin Conversion Accelerator, Proconvertin, Stable Factor, Cothromboplastin, Prothrombin Accelerator or Autoprothrombin I, and Their Subsequent Merging into Factor VII.

    Science.gov (United States)

    Girolami, Antonio; Cosi, Elisabetta; Santarossa, Claudia; Ferrari, Silvia; Luigia Randi, Maria

    2015-06-01

    Factor VII (FVII) deficiency is one of the two congenital coagulation disorders that was not discovered by the description of a new bleeding patient whose clotting pattern did not fit the blood coagulation knowledge of the time (the other is factor XIII deficiency). The existence of an additional factor capable of accelerating the conversion of prothrombin into thrombin was suspected before 1951, the year in which the first family with FVII deficiency was discovered. As several investigators were involved in the discovery of FVII deficiency from both sides of the Atlantic, several different names were tentatively suggested to define this entity, namely stable factor (in contrast with labile factor or FV), cothromboplastin, proconvertin, serum prothrombin conversion accelerator, prothrombin acceleration, and autoprothrombin I. The last term was proposed by those who denied the existence of this new entity, which was instead considered to be a derivate of prothrombin activation, namely autoprothrombin. The description of several families, from all over the world, of the same defect, however clearly demonstrated the singularity of the condition. Factor VII was then proposed to define this protein. In subsequent years, several variants were described with peculiar reactivity toward tissue thromboplastins of different origin. Molecular biology techniques demonstrated several gene mutations, usually missense mutations, often involving exon 8 of the FVII gene. Later studies dealt with the relation of FVII with tissue factor and activated FVII (FVIIa). The evaluation of circulating FVIIa was made possible by the use of a truncated form of tissue factor, which is only sensitive to FVIIa present in the circulation. The development of FVII concentrates, both plasma derived and recombinant, has facilitated therapeutic management of FVII-deficient patients. The use of FVIIa concentrates was noted to be associated with the occasional occurrence of thrombotic events, mainly

  18. Preoperative Risk Factors for Conversion of Laparoscopic Cholecystectomy to Open Surgery - A Systematic Review and Meta-Analysis of Observational Studies

    DEFF Research Database (Denmark)

    Rothman, Josephine Philip; Burcharth, Jakob; Pommergaard, Hans-Christian

    2016-01-01

    were suitable for 7 meta-analyses on age, gender, body mass index, previous abdominal surgery, severity of disease, white blood cell count, and gallbladder wall thickness. CONCLUSIONS: A gallbladder wall thicker than 4-5 mm, a contracted gallbladder, age above 60 or 65, male gender, and acute...... cholecystitis were risk factors for the conversion of laparoscopic cholecystectomy to open surgery. Furthermore, there was no association between diabetes mellitus or white blood cell count and conversion to open surgery....

  19. Clinical assessment of bone quality of human extraction sockets after conversion with growth factors.

    Science.gov (United States)

    Ntounis, Athanasios; Geurs, Nico; Vassilopoulos, Philip; Reddy, Michael

    2015-01-01

    The study was conducted to evaluate the effect of mineralized freeze-dried bone allograft (FDBA), alone or in combination with growth factors in extraction sockets, on subjective assessment of bone quality during implant placement. Forty-one patients whose treatment plan involved extraction of anterior or premolar teeth were randomized into four groups: Group 1, collagen plug (control); Group 2, FDBA/β-tricalcium phosphate (β-TCP)/collagen plug; Group 3, FDBA/β-TCP/platelet-rich plasma (PRP)/collagen plug; Group 4, FDBA/β-TCP/recombinant human platelet-derived growth factor BB (rhPDGF-BB)/collagen plug. After 8 weeks of healing, implants were placed. The clinicians assessed bone quality according to the Misch classification. A benchtop calibration exercise test was conducted to evaluate agreement and accuracy of operators in recognizing different bone qualities. Differences were analyzed using one-way analysis of variance (ANOVA) or chi-square tests for continuous and categorical data. Pairwise comparisons were tested using least squares means (LS means). Spearman correlation coefficients were used to evaluate the relationship of bone growth with potential confounders. P .05). Inclusion of bone grafting is associated with a shift from D4 quality to D3 quality bone. Inclusion of PRP in bone grafting eliminates the incidence of D4 bone, establishing D3 and D2 quality bone as prevalent (56% vs. 42%, respectively). Inclusion of rhPDGF-BB and β-TCP in combination with the bone grafting has the same effect, although D2 quality is less prevalent. When compared to sockets grafted with FDBA/β-TCP/collagen plug alone, the sockets with growth factors demonstrated fewer residual bone graft particles. (1) Inclusion of bone grafting enhanced bone quality as assessed during implant placement. (2) Overall inclusion of PRP and rhPDGF-BB enhanced subjective bone quality, eliminating incidence of D4 quality in human extraction sockets. (3) The use of PRP or rhPDGF-BB may

  20. Spontaneous and radiation induced gene conversion in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Rao, B.S.; Murthy, M.S.S.

    1977-01-01

    Spontaneous and radiation induced gene conversion to arginine independence was studied in a heteroallelic diploid strain of yeast Saccharomyces cerevisiae BZ 34. When stationary phase cells were incubated in phosphate buffer (pH 7 ) at 30 0 C under aerated condition for 48 hours, the conversion frequency increased by a factor of about 1000 times the background. This was found to be so even when the cells were incubated in saline (0.85%) or distilled water. Various conditions influencing this enhancement have been investigated. Conversion frequency enhancement was not significant under anoxic conditions and was absent at low temperatures and in log phase cells. Caffeine could inhibit this enhancement when present in the suspension medium. These results can be explained on the basis of the induction of meiosis in cells held in buffer. Microscopic examination confirmed this view. Under conditions not favourable for the onset of meiosis there is no significant enhancement in conversion frequency. In stationary phase cells exposed to series of gamma doses, the conversion frequency increases with dose. Post irradiation incubation in buffer further increases the conversion frequency. However, the increase expressed as the ratio of the conversion frequency on buffer holding to that on immediate plating decreased with increasing dose. This decrease in enhancement with increasing dose may be due to the dose dependent inhibition of meiosis. (author)

  1. Application of geometry correction factors for low-level waste package dose measurements. Revision 1

    International Nuclear Information System (INIS)

    Chandler, M.C.; Parish, B.

    1995-01-01

    Plans are to determine the Cs-137 content of low-level waste packages generated in High-Level Waste by measuring the radiation level at a specified distance from the package with a hand-held radiation instrument. The measurement taken at this specified distance, either 3 or 5 feet, is called the far-field measurement. This report documents a method for adjusting the gamma exposure rate (mR/hr) reading used in dose-to-curie determinations when the far-field measurement equals the background reading. This adjustment is necessary to reduce the conservatism resulting from using a minimum detection limit exposure rate for the dose-to-curie determination for the far-field measurement position. To accomplish this adjustment, the near-field (5 cm) measurement is multiplied by a geometry correction factor to obtain an estimate of the far field exposure rate (which is below instrument sensitivity). This estimate of the far field exposure rate is used to estimate the Cs-137 curie content of the package. This report establishes the geometry correction factors for the dose-to-curie determination when the far-field gamma exposure measurement equals the background reading. This report also provides a means of demonstrating compliance to 1S Manual requirements for exposure rate readings at different locations from waste packages while specifying only two measurement positions. This demonstration of compliance is necessary to minimize the number of locations exposure rate measurements that are required, i.e., ALARA

  2. SU-F-BRD-15: The Impact of Dose Calculation Algorithm and Hounsfield Units Conversion Tables On Plan Dosimetry for Lung SBRT

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, L; Yorke, E; Lim, S; Mechalakos, J; Rimner, A [Memorial Sloan-Kettering Cancer Center, NY, NY (United States)

    2014-06-15

    Purpose: To assess dosimetric differences in IMRT lung stereotactic body radiotherapy (SBRT) plans calculated with Varian AAA and Acuros (AXB) and with vendor-supplied (V) versus in-house (IH) measured Hounsfield units (HU) to mass and HU to electron density conversion tables. Methods: In-house conversion tables were measured using Gammex 472 density-plug phantom. IMRT plans (6 MV, Varian TrueBeam, 6–9 coplanar fields) meeting departmental coverage and normal tissue constraints were retrospectively generated for 10 lung SBRT cases using Eclipse Vn 10.0.28 AAA with in-house tables (AAA/IH). Using these monitor units and MLC sequences, plans were recalculated with AAA and vendor tables (AAA/V) and with AXB with both tables (AXB/IH and AXB/V). Ratios to corresponding AAA/IH values were calculated for PTV D95, D01, D99, mean-dose, total and ipsilateral lung V20 and chestwall V30. Statistical significance of differences was judged by Wilcoxon Signed Rank Test (p<0.05). Results: For HU<−400 the vendor HU-mass density table was notably below the IH table. PTV D95 ratios to AAA/IH, averaged over all patients, are 0.963±0.073 (p=0.508), 0.914±0.126 (p=0.011), and 0.998±0.001 (p=0.005) for AXB/IH, AXB/V and AAA/V respectively. Total lung V20 ratios are 1.006±0.046 (p=0.386), 0.975±0.080 (p=0.514) and 0.998±0.002 (p=0.007); ipsilateral lung V20 ratios are 1.008±0.041(p=0.284), 0.977±0.076 (p=0.443), and 0.998±0.018 (p=0.005) for AXB/IH, AXB/V and AAA/V respectively. In 7 cases, ratios to AAA/IH were within ± 5% for all indices studied. For 3 cases characterized by very low lung density and small PTV (19.99±8.09 c.c.), PTV D95 ratio for AXB/V ranged from 67.4% to 85.9%, AXB/IH D95 ratio ranged from 81.6% to 93.4%; there were large differences in other studied indices. Conclusion: For AXB users, careful attention to HU conversion tables is important, as they can significantly impact AXB (but not AAA) lung SBRT plans. Algorithm selection is also important for

  3. Conversion of MyoD to a Neurogenic Factor: Binding Site Specificity Determines Lineage

    Directory of Open Access Journals (Sweden)

    Abraham P. Fong

    2015-03-01

    Full Text Available MyoD and NeuroD2, master regulators of myogenesis and neurogenesis, bind to a “shared” E-box sequence (CAGCTG and a “private” sequence (CAGGTG or CAGATG, respectively. To determine whether private-site recognition is sufficient to confer lineage specification, we generated a MyoD mutant with the DNA-binding specificity of NeuroD2. This chimeric mutant gained binding to NeuroD2 private sites but maintained binding to a subset of MyoD-specific sites, activating part of both the muscle and neuronal programs. Sequence analysis revealed an enrichment for PBX/MEIS motifs at the subset of MyoD-specific sites bound by the chimera, and point mutations that prevent MyoD interaction with PBX/MEIS converted the chimera to a pure neurogenic factor. Therefore, redirecting MyoD binding from MyoD private sites to NeuroD2 private sites, despite preserved binding to the MyoD/NeuroD2 shared sites, is sufficient to change MyoD from a master regulator of myogenesis to a master regulator of neurogenesis.

  4. Comparison of analytic source models for head scatter factor calculation and planar dose calculation for IMRT

    International Nuclear Information System (INIS)

    Yan Guanghua; Liu, Chihray; Lu Bo; Palta, Jatinder R; Li, Jonathan G

    2008-01-01

    The purpose of this study was to choose an appropriate head scatter source model for the fast and accurate independent planar dose calculation for intensity-modulated radiation therapy (IMRT) with MLC. The performance of three different head scatter source models regarding their ability to model head scatter and facilitate planar dose calculation was evaluated. A three-source model, a two-source model and a single-source model were compared in this study. In the planar dose calculation algorithm, in-air fluence distribution was derived from each of the head scatter source models while considering the combination of Jaw and MLC opening. Fluence perturbations due to tongue-and-groove effect, rounded leaf end and leaf transmission were taken into account explicitly. The dose distribution was calculated by convolving the in-air fluence distribution with an experimentally determined pencil-beam kernel. The results were compared with measurements using a diode array and passing rates with 2%/2 mm and 3%/3 mm criteria were reported. It was found that the two-source model achieved the best agreement on head scatter factor calculation. The three-source model and single-source model underestimated head scatter factors for certain symmetric rectangular fields and asymmetric fields, but similar good agreement could be achieved when monitor back scatter effect was incorporated explicitly. All the three source models resulted in comparable average passing rates (>97%) when the 3%/3 mm criterion was selected. The calculation with the single-source model and two-source model was slightly faster than the three-source model due to their simplicity

  5. Comparison of analytic source models for head scatter factor calculation and planar dose calculation for IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Yan Guanghua [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States); Liu, Chihray; Lu Bo; Palta, Jatinder R; Li, Jonathan G [Department of Radiation Oncology, University of Florida, Gainesville, FL 32610-0385 (United States)

    2008-04-21

    The purpose of this study was to choose an appropriate head scatter source model for the fast and accurate independent planar dose calculation for intensity-modulated radiation therapy (IMRT) with MLC. The performance of three different head scatter source models regarding their ability to model head scatter and facilitate planar dose calculation was evaluated. A three-source model, a two-source model and a single-source model were compared in this study. In the planar dose calculation algorithm, in-air fluence distribution was derived from each of the head scatter source models while considering the combination of Jaw and MLC opening. Fluence perturbations due to tongue-and-groove effect, rounded leaf end and leaf transmission were taken into account explicitly. The dose distribution was calculated by convolving the in-air fluence distribution with an experimentally determined pencil-beam kernel. The results were compared with measurements using a diode array and passing rates with 2%/2 mm and 3%/3 mm criteria were reported. It was found that the two-source model achieved the best agreement on head scatter factor calculation. The three-source model and single-source model underestimated head scatter factors for certain symmetric rectangular fields and asymmetric fields, but similar good agreement could be achieved when monitor back scatter effect was incorporated explicitly. All the three source models resulted in comparable average passing rates (>97%) when the 3%/3 mm criterion was selected. The calculation with the single-source model and two-source model was slightly faster than the three-source model due to their simplicity.

  6. Clinical Factors Associated with Dose of Loop Diuretics After Pediatric Cardiac Surgery: Post Hoc Analysis.

    Science.gov (United States)

    Haiberger, Roberta; Favia, Isabella; Romagnoli, Stefano; Cogo, Paola; Ricci, Zaccaria

    2016-06-01

    A post hoc analysis of a randomized controlled trial comparing the clinical effects of furosemide and ethacrynic acid was conducted. Infants undergoing cardiac surgery with cardiopulmonary bypass were included in order to explore which clinical factors are associated with diuretic dose in infants with congenital heart disease. Overall, 67 patients with median (interquartile range) age of 48 (13-139) days were enrolled. Median diuretic dose was 0.34 (0.25-0.4) mg/kg/h at the end of postoperative day (POD) 0 and it significantly decreased (p = 0.04) over the following PODs; during this period, the ratio between urine output and diuretic dose increased significantly (p = 0.04). Age (r -0.26, p = 0.02), weight (r -0.28, p = 0.01), cross-clamp time (r 0.27, p = 0.03), administration of ethacrynic acid (OR 0.01, p = 0.03), and, at the end of POD0, creatinine levels (r 0.3, p = 0.009), renal near-infrared spectroscopy saturation (-0.44, p = 0.008), whole-blood neutrophil gelatinase-associated lipocalin levels (r 0.30, p = 0.01), pH (r -0.26, p = 0.02), urinary volume (r -0.2755, p = 0.03), and fluid balance (r 0.2577, p = 0.0266) showed a significant association with diuretic dose. At multivariable logistic regression cross-clamp time (OR 1.007, p = 0.04), use of ethacrynic acid (OR 0.2, p = 0.01) and blood pH at the end of POD0 (OR 0.0001, p = 0.03) was independently associated with diuretic dose. Early resistance to loop diuretics continuous infusion is evident in post-cardiac surgery infants: Higher doses are administered to patients with lower urinary output. Independently associated variables with diuretic dose in our population appeared to be cross-clamping time, the administration of ethacrynic acid, and blood pH.

  7. SU-E-J-122: The CBCT Dose Calculation Using a Patient Specific CBCT Number to Mass Density Conversion Curve Based On a Novel Image Registration and Organ Mapping Method in Head-And-Neck Radiation Therapy

    International Nuclear Information System (INIS)

    Zhou, J; Lasio, G; Chen, S; Zhang, B; Langen, K; Prado, K; D’Souza, W; Yi, B; Huang, J

    2015-01-01

    Purpose: To develop a CBCT HU correction method using a patient specific HU to mass density conversion curve based on a novel image registration and organ mapping method for head-and-neck radiation therapy. Methods: There are three steps to generate a patient specific CBCT HU to mass density conversion curve. First, we developed a novel robust image registration method based on sparseness analysis to register the planning CT (PCT) and the CBCT. Second, a novel organ mapping method was developed to transfer the organs at risk (OAR) contours from the PCT to the CBCT and corresponding mean HU values of each OAR were measured in both the PCT and CBCT volumes. Third, a set of PCT and CBCT HU to mass density conversion curves were created based on the mean HU values of OARs and the corresponding mass density of the OAR in the PCT. Then, we compared our proposed conversion curve with the traditional Catphan phantom based CBCT HU to mass density calibration curve. Both curves were input into the treatment planning system (TPS) for dose calculation. Last, the PTV and OAR doses, DVH and dose distributions of CBCT plans are compared to the original treatment plan. Results: One head-and-neck cases which contained a pair of PCT and CBCT was used. The dose differences between the PCT and CBCT plans using the proposed method are −1.33% for the mean PTV, 0.06% for PTV D95%, and −0.56% for the left neck. The dose differences between plans of PCT and CBCT corrected using the CATPhan based method are −4.39% for mean PTV, 4.07% for PTV D95%, and −2.01% for the left neck. Conclusion: The proposed CBCT HU correction method achieves better agreement with the original treatment plan compared to the traditional CATPhan based calibration method

  8. SU-E-J-122: The CBCT Dose Calculation Using a Patient Specific CBCT Number to Mass Density Conversion Curve Based On a Novel Image Registration and Organ Mapping Method in Head-And-Neck Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, J [University of Maryland School of Medicine, Bel Air, MD (United States); Lasio, G; Chen, S; Zhang, B; Langen, K; Prado, K; D’Souza, W [University of Maryland School of Medicine, Baltimore, MD (United States); Yi, B [Univ. of Maryland School Of Medicine, Baltimore, MD (United States); Huang, J [University of Texas at Arlington, Arlington, TX (United States)

    2015-06-15

    Purpose: To develop a CBCT HU correction method using a patient specific HU to mass density conversion curve based on a novel image registration and organ mapping method for head-and-neck radiation therapy. Methods: There are three steps to generate a patient specific CBCT HU to mass density conversion curve. First, we developed a novel robust image registration method based on sparseness analysis to register the planning CT (PCT) and the CBCT. Second, a novel organ mapping method was developed to transfer the organs at risk (OAR) contours from the PCT to the CBCT and corresponding mean HU values of each OAR were measured in both the PCT and CBCT volumes. Third, a set of PCT and CBCT HU to mass density conversion curves were created based on the mean HU values of OARs and the corresponding mass density of the OAR in the PCT. Then, we compared our proposed conversion curve with the traditional Catphan phantom based CBCT HU to mass density calibration curve. Both curves were input into the treatment planning system (TPS) for dose calculation. Last, the PTV and OAR doses, DVH and dose distributions of CBCT plans are compared to the original treatment plan. Results: One head-and-neck cases which contained a pair of PCT and CBCT was used. The dose differences between the PCT and CBCT plans using the proposed method are −1.33% for the mean PTV, 0.06% for PTV D95%, and −0.56% for the left neck. The dose differences between plans of PCT and CBCT corrected using the CATPhan based method are −4.39% for mean PTV, 4.07% for PTV D95%, and −2.01% for the left neck. Conclusion: The proposed CBCT HU correction method achieves better agreement with the original treatment plan compared to the traditional CATPhan based calibration method.

  9. High dose rate brachytherapy for carcinoma of the cervix: risk factors for late rectal complications

    International Nuclear Information System (INIS)

    Uno, Takashi; Itami, Jun; Aruga, Moriyo; Kotaka, Kikuo; Fujimoto, Hajime; Minoura, Shigeki

    1996-01-01

    Purpose/Objective: To determine the incidence of late rectal complications in patients treated with high dose rate brachytherapy for FIGO stage IIB, IIIB carcinoma of the uterine cervix, and to evaluate the treatment factors associated with an increased probability of treatment complications. Materials and Methods: Records of 100 patients with FIGO IIB or IIIB cervical carcinoma treated with definitive irradiation using high dose rate intracavitary brachytherapy (HDR-ICR) between 1977 and 1994 were retrospectively reviewed. For each HDR-ICR session, 6 Gy isodose volume was reconstructed three dimensionally and the following three parameters were determined to represent this isodose volume, length (L); maximum longitudinal distance of 6 Gy isodose area in an oblique frontal plane containing the intrauterine applicator, width (W); maximum width of 6 Gy isodose area in the same plane, height (H); maximum dimension of 6 Gy isodose area perpendicular to the intrauterine applicator determined in the oblique sagittal plane. Point P/Q (2 cm ventral/dorsal from the proximal retention point of the intrauterine source) and point R/S (2 cm ventral/dorsal from the midpoint of the ovoid sources) were also defined retrospectively and HDR-ICR dose at these points were calculated. Statistical analyses were performed to determine the treatment factors predictive of late rectal complications. Results: The 5-year cumulative cause-specific disease-free survival rate was 50% for all, 74% for Stage IIB, and 38% for Stage IIIB, with a significant difference between two FIGO Stages (p=0.0004). Of patients treated for both stages, 30% and 36% had experienced moderate to severe (Grade 2-4) complications at 3 and 5 years, respectively. Average H value (p=0.013) and cumulative point S dose by HDR-ICR (p=0.020) were significantly correlated with the incidence of late rectal complications (Student's t-test), whereas these factors did not significantly affect the probability of pelvic control. No

  10. Dose and dose rate extrapolation factors for malignant and non-malignant health endpoints after exposure to gamma and neutron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Van; Little, Mark P. [National Cancer Institute, Radiation Epidemiology Branch, Rockville, MD (United States)

    2017-11-15

    Murine experiments were conducted at the JANUS reactor in Argonne National Laboratory from 1970 to 1992 to study the effect of acute and protracted radiation dose from gamma rays and fission neutron whole body exposure. The present study reports the reanalysis of the JANUS data on 36,718 mice, of which 16,973 mice were irradiated with neutrons, 13,638 were irradiated with gamma rays, and 6107 were controls. Mice were mostly Mus musculus, but one experiment used Peromyscus leucopus. For both types of radiation exposure, a Cox proportional hazards model was used, using age as timescale, and stratifying on sex and experiment. The optimal model was one with linear and quadratic terms in cumulative lagged dose, with adjustments to both linear and quadratic dose terms for low-dose rate irradiation (<5 mGy/h) and with adjustments to the dose for age at exposure and sex. After gamma ray exposure there is significant non-linearity (generally with upward curvature) for all tumours, lymphoreticular, respiratory, connective tissue and gastrointestinal tumours, also for all non-tumour, other non-tumour, non-malignant pulmonary and non-malignant renal diseases (p < 0.001). Associated with this the low-dose extrapolation factor, measuring the overestimation in low-dose risk resulting from linear extrapolation is significantly elevated for lymphoreticular tumours 1.16 (95% CI 1.06, 1.31), elevated also for a number of non-malignant endpoints, specifically all non-tumour diseases, 1.63 (95% CI 1.43, 2.00), non-malignant pulmonary disease, 1.70 (95% CI 1.17, 2.76) and other non-tumour diseases, 1.47 (95% CI 1.29, 1.82). However, for a rather larger group of malignant endpoints the low-dose extrapolation factor is significantly less than 1 (implying downward curvature), with central estimates generally ranging from 0.2 to 0.8, in particular for tumours of the respiratory system, vasculature, ovary, kidney/urinary bladder and testis. For neutron exposure most endpoints, malignant and

  11. Joint Dictionary Learning-Based Non-Negative Matrix Factorization for Voice Conversion to Improve Speech Intelligibility After Oral Surgery.

    Science.gov (United States)

    Fu, Szu-Wei; Li, Pei-Chun; Lai, Ying-Hui; Yang, Cheng-Chien; Hsieh, Li-Chun; Tsao, Yu

    2017-11-01

    Objective: This paper focuses on machine learning based voice conversion (VC) techniques for improving the speech intelligibility of surgical patients who have had parts of their articulators removed. Because of the removal of parts of the articulator, a patient's speech may be distorted and difficult to understand. To overcome this problem, VC methods can be applied to convert the distorted speech such that it is clear and more intelligible. To design an effective VC method, two key points must be considered: 1) the amount of training data may be limited (because speaking for a long time is usually difficult for postoperative patients); 2) rapid conversion is desirable (for better communication). Methods: We propose a novel joint dictionary learning based non-negative matrix factorization (JD-NMF) algorithm. Compared to conventional VC techniques, JD-NMF can perform VC efficiently and effectively with only a small amount of training data. Results: The experimental results demonstrate that the proposed JD-NMF method not only achieves notably higher short-time objective intelligibility (STOI) scores (a standardized objective intelligibility evaluation metric) than those obtained using the original unconverted speech but is also significantly more efficient and effective than a conventional exemplar-based NMF VC method. Conclusion: The proposed JD-NMF method may outperform the state-of-the-art exemplar-based NMF VC method in terms of STOI scores under the desired scenario. Significance: We confirmed the advantages of the proposed joint training criterion for the NMF-based VC. Moreover, we verified that the proposed JD-NMF can effectively improve the speech intelligibility scores of oral surgery patients. Objective: This paper focuses on machine learning based voice conversion (VC) techniques for improving the speech intelligibility of surgical patients who have had parts of their articulators removed. Because of the removal of parts of the articulator, a patient

  12. CT- and MRI-based volumetry of resected liver specimen: Comparison to intraoperative volume and weight measurements and calculation of conversion factors

    International Nuclear Information System (INIS)

    Karlo, C.; Reiner, C.S.; Stolzmann, P.; Breitenstein, S.; Marincek, B.; Weishaupt, D.; Frauenfelder, T.

    2010-01-01

    Objective: To compare virtual volume to intraoperative volume and weight measurements of resected liver specimen and calculate appropriate conversion factors to reach better correlation. Methods: Preoperative (CT-group, n = 30; MRI-group, n = 30) and postoperative MRI (n = 60) imaging was performed in 60 patients undergoing partial liver resection. Intraoperative volume and weight of the resected liver specimen was measured. Virtual volume measurements were performed by two readers (R1,R2) using dedicated software. Conversion factors were calculated. Results: Mean intraoperative resection weight/volume: CT: 855 g/852 mL; MRI: 872 g/860 mL. Virtual resection volume: CT: 960 mL(R1), 982 mL(R2); MRI: 1112 mL(R1), 1115 mL(R2). Strong positive correlation for both readers between intraoperative and virtual measurements, mean of both readers: CT: R = 0.88(volume), R = 0.89(weight); MRI: R = 0.95(volume), R = 0.92(weight). Conversion factors: 0.85(CT), 0.78(MRI). Conclusion: CT- or MRI-based volumetry of resected liver specimen is accurate and recommended for preoperative planning. A conversion of the result is necessary to improve intraoperative and virtual measurement correlation. We found 0.85 for CT- and 0.78 for MRI-based volumetry the most appropriate conversion factors.

  13. Report of the Nuclear Energy Agency expert group on gut transfer factors: implications for dose per unit intake

    International Nuclear Information System (INIS)

    1988-01-01

    This note describes the gut transfer factors recommended by an Expert Group of the Nuclear Energy Agency for intakes of certain important elements in food and drinking water. The evidence behind the recommendations is discussed and their implications for dose per unit intake is investigated. It is found that in many cases the dose per unit intake calculated using the gut uptake factor recommended by the Expert Group is similar to that calculated using the recommendations of ICRP Publication 30. However, in some cases there are substantial increases in dose per unit intake. The largest increases are by a factor of fifty for intakes of certain thorium isotopes by infants. (author)

  14. Scattering factor evaluation for internal dose assessment due to 60Co

    International Nuclear Information System (INIS)

    Gautam, Y.P.; Kumar, A.; Sharma, S.; Sharma, A.K.; Dube, B.; Hegde, A.G.

    2008-01-01

    Guidelines for the assessment of internal doses from monitoring suggest default measurement of uncertainties (i.e. lognormal scattering factor, SF) to be used for different types of monitoring data. In this paper, SF values have been evaluated for internal contamination due to 60 Co in two cases using whole body counting data. SF values of 1.04 and 1.03 were obtained for case I and II respectively while SF value of 1.03 was obtained using bioassay data for case I. SF evaluated is in good agreement with the default values given by IDEAS guidelines. (author)

  15. Transfer factors for assessing the dose from radionuclides in agricultural products

    International Nuclear Information System (INIS)

    Ng, Y.C.; Colsher, C.S.; Thompson, S.E.

    1979-01-01

    Transfer factors to predict the environmental transport of radionuclides through terrestrial foodchains to man were derived from the literature for radionuclides associated with the nuclear fuel cycle. We present updated transfer coefficients to predict the concentration of a radionuclide in cow's milk and other animal products and concentration factors (CF) to predict the concentration in a food or feed crop from that in soil. Where possible we note the variation of the transfer factor with physical and chemical form of the radionuclide and environmental factors, and characterize the distribution and uncertainty in the estimate. The updated transfer factors are compared with those listed in regulatory guides. The new estimates lead to recommended changes (both increases and decreases) in the listed transfer coefficients for milk and meat and to the suggested practice of adopting multiple soil-to-plant CF's that vary with the type of crop and soil in the place of a single generic CF to predict the concentration of a radionuclide in a crop from that in soil. The updated transfer factors will be useful to assess the dose from radionuclides released from nuclear facilities and evaluating compliance with regulations governing the release of radionuclides

  16. Determining the spatial variability of wetland soil bulk density, organic matter, and the conversion factor between organic matter and organic carbon across coastal Louisiana, U.S.A.

    Science.gov (United States)

    Wang, Hongqing; Piazza, Sarai C.; Sharp, Leigh A.; Stagg, Camille L.; Couvillion, Brady R.; Steyer, Gregory D.; McGinnis, Thomas E.

    2016-01-01

    Soil bulk density (BD), soil organic matter (SOM) content, and a conversion factor between SOM and soil organic carbon (SOC) are often used in estimating SOC sequestration and storage. Spatial variability in BD, SOM, and the SOM–SOC conversion factor affects the ability to accurately estimate SOC sequestration, storage, and the benefits (e.g., land building area and vertical accretion) associated with wetland restoration efforts, such as marsh creation and sediment diversions. There are, however, only a few studies that have examined large-scale spatial variability in BD, SOM, and SOM–SOC conversion factors in coastal wetlands. In this study, soil cores, distributed across the entire coastal Louisiana (approximately 14,667 km2) were used to examine the regional-scale spatial variability in BD, SOM, and the SOM–SOC conversion factor. Soil cores for BD and SOM analyses were collected during 2006–09 from 331 spatially well-distributed sites in the Coastwide Reference Monitoring System network. Soil cores for the SOM–SOC conversion factor analysis were collected from 15 sites across coastal Louisiana during 2006–07. Results of a split-plot analysis of variance with incomplete block design indicated that BD and SOM varied significantly at a landscape level, defined by both hydrologic basins and vegetation types. Vertically, BD and SOM varied significantly among different vegetation types. The SOM–SOC conversion factor also varied significantly at the landscape level. This study provides critical information for the assessment of the role of coastal wetlands in large regional carbon budgets and the estimation of carbon credits from coastal restoration.

  17. Comparison of biophysical factors influencing on emphysema quantification with low-dose CT

    Science.gov (United States)

    Heo, Chang Yong; Kim, Jong Hyo

    2014-03-01

    Emphysema Index(EI) measurements in MDCT is known to be influenced by various biophysical factors such as total lung volume, and body size. We investigated the association of the four biophysical factors with emphysema index in low-dose MDCT. In particular, we attempted to identify a potentially stronger biophysical factor than total lung volume. A total of 400 low-dose MDCT volumes taken at 120kVp, 40mAs, 1mm thickness, and B30f reconstruction kernel were used. The lungs, airways, and pulmonary vessels were automatically segmented, and two Emphysema Indices, relative area below -950HU(RA950) and 15th percentile(Perc15), were extracted from the segmented lungs. The biophysical factors such as total lung volume(TLV), mode of lung attenuation(ModLA), effective body diameter(EBD), and the water equivalent body diameter(WBD) were estimated from the segmented lung and body area. The association of biophysical factors with emphysema indices were evaluated by correlation coefficients. The mean emphysema indices were 8.3±5.5(%) in RA950, and -930±18(HU) in Perc15. The estimates of biophysical factors were 4.7±1.0(L) in TLV, -901±21(HU) in ModLA, 26.9±2.2(cm) in EBD, and 25.9±2.6(cm) in WBD. The correlation coefficients of biophysical factors with RA950 were 0.73 in TLV, 0.94 in ModLA, 0.31 in EBD, and 0.18 WBD, the ones with Perc15 were 0.74 in TLV, 0.98 in ModLA, 0.29 in EBD, and 0.15 WBD. Study results revealed that two biophysical factors, TLV and ModLA, mostly affects the emphysema indices. In particular, the ModLA exhibited strongest correlation of 0.98 with Perc15, which indicating the ModLA is the most significant confounding biophysical factor in emphysema indices measurement.

  18. Growth hormone administration stimulates energy expenditure and extrathyroidal conversion of thyroxine to triiodothyronine in a dose-dependent manner and suppresses circadian thyrotrophin levels: studies in GH-deficient adults

    DEFF Research Database (Denmark)

    Laursen, Torben; Jørgensen, Jens Otto Lunde; Møller, Jens

    1994-01-01

    . CONCLUSIONS: GH administration stimulated peripheral T4 to T3 conversion in a dose-dependent manner. Serum T3 levels were subnormal despite T4 substitution when the patients were off GH but normalized with GH therapy. Energy expenditure increased with GH and correlated with free T3 levels. GH caused......Abstract OBJECTIVE: The impact of exogenous GH on thyroid function remains controversial although most data add support to a stimulation of peripheral T4 to T3 conversion. For further elucidation we evaluated iodothyronine and circadian TSH levels in GH-deficient patients as part of a GH dose...... without GH, whereas GH therapy significantly suppressed the TSH levels and blunted the circadian rhythm (mean TSH levels (mU/l) 0.546 +/- 0.246 (no GH) vs 0.066 +/- 0.031 (2 IU GH) (P

  19. Multivariate analysis of factors predicting prostate dose in intensity-modulated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Tomita, Tsuneyuki [Division of Radiology, Osaka Red Cross Hospital, Osaka (Japan); Nakamura, Mitsuhiro, E-mail: m_nkmr@kuhp.kyoto-u.ac.jp [Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Hirose, Yoshinori; Kitsuda, Kenji; Notogawa, Takuya; Miki, Katsuhito [Division of Radiology, Osaka Red Cross Hospital, Osaka (Japan); Nakamura, Kiyonao; Ishigaki, Takashi [Department of Radiation Oncology, Osaka Red Cross Hospital, Osaka (Japan)

    2014-01-01

    We conducted a multivariate analysis to determine relationships between prostate radiation dose and the state of surrounding organs, including organ volumes and the internal angle of the levator ani muscle (LAM), based on cone-beam computed tomography (CBCT) images after bone matching. We analyzed 270 CBCT data sets from 30 consecutive patients receiving intensity-modulated radiation therapy for prostate cancer. With patients in the supine position on a couch with the HipFix system, data for center of mass (COM) displacement of the prostate and the state of individual organs were acquired and compared between planning CT and CBCT scans. Dose distributions were then recalculated based on CBCT images. The relative effects of factors on the variance in COM, dose covering 95% of the prostate volume (D{sub 95%}), and percentage of prostate volume covered by the 100% isodose line (V{sub 100%}) were evaluated by a backward stepwise multiple regression analysis. COM displacement in the anterior-posterior direction (COM{sub AP}) correlated significantly with the rectum volume (δVr) and the internal LAM angle (δθ; R = 0.63). Weak correlations were seen for COM in the left-right (R = 0.18) and superior-inferior directions (R = 0.31). Strong correlations between COM{sub AP} and prostate D{sub 95%} and V{sub 100%} were observed (R ≥ 0.69). Additionally, the change ratios in δVr and δθ remained as predictors of prostate D{sub 95%} and V{sub 100%}. This study shows statistically that maintaining the same rectum volume and LAM state for both the planning CT simulation and treatment is important to ensure the correct prostate dose in the supine position with bone matching.

  20. Dose conformity of gamma knife radiosurgery and risk factors for complications

    International Nuclear Information System (INIS)

    Nakamura, Jean L.; Verhey, Lynn J.; Smith, Vernon; Petti, Paula L.; Lamborn, Kathleen R.; Larson, David A.; Wara, William M.; McDermott, Michael W.; Sneed, Penny K.

    2001-01-01

    Purpose: To quantitatively evaluate dose conformity achieved using Gamma Knife radiosurgery, compare results with those reported in the literature, and evaluate risk factors for complications. Methods and Materials: All lesions treated at our institution with Gamma Knife radiosurgery from May 1993 (when volume criteria were routinely recorded) through December 1998 were reviewed. Lesions were excluded from analysis for reasons listed below. Conformity index (the ratio of prescription volume to target volume) was calculated for all evaluable lesions and for lesions comparable to those reported in the literature on conformity of linac radiosurgery. Univariate Cox regression models were used to test for associations between treatment parameters and toxicity. Results: Of 1612 targets treated in 874 patients, 274 were excluded, most commonly for unavailability of individual prescription volume data because two or more lesions were included within the same dose matrix (176 lesions), intentional partial coverage for staged treatment of large arteriovenous malformations (AVMs) (33 lesions), and missing target volume data (26 lesions). The median conformity indices were 1.67 for all 1338 evaluable lesions and 1.40-1.43 for lesions comparable to two linac radiosurgery series that reported conformity indices of 1.8 and 2.7, respectively. Among all 651 patients evaluable for complications, there were one Grade 5, eight Grade 4, and 27 Grade 3 complications. Increased risk of toxicity was associated with larger target volume, maximum lesion diameter, prescription volume, or volume of nontarget tissue within the prescription volume. Conclusions: Gamma Knife radiosurgery achieves much more conformal dose distributions than those reported for conventional linac radiosurgery and somewhat more conformal dose distributions than sophisticated linac radiosurgery techniques. Larger target, nontarget, or prescription volumes are associated with increased risk of toxicity

  1. HIGH-DOSE CHEMOTHERAPY WITH STEM-CELL REINFUSION AND GROWTH-FACTOR SUPPORT FOR SOLID TUMORS

    NARCIS (Netherlands)

    DEVRIES, EGE; DEGRAAF, H; VANDERGRAAF, WTA; MULDER, NH; Boonstra, A.

    1995-01-01

    With the help of stem cell reinfusion and hematopoietic growth factors, it is possible to get up to a ten-fold dose increase for certain chemotherapeutic drugs, A number of reasons may have made high-dose chemotherapy less dangerous and the fore more acceptable in a more upfront treatment setting,

  2. Experimental measures of the energy rate absorbed in the aluminium and the comparison with the calculation using factors of dose and carrier of electrons by means of MCNP code

    International Nuclear Information System (INIS)

    Federico, Claudio A.; Vieira, Wilson J.; Rigolon, Leda S.Y.; Geraldo, Luiz P.

    2000-01-01

    In this paper are presented the results of a Monte Carlo calculation for the energy deposition rate in aluminum plates, when a collimated beam of gamma-rays produced by thermal neutrons capture in nickel target passes through them. The absorbed dose rate as a function of the aluminum thickness crossed by the gamma beam has been measured by using CaSO e :Dy thermoluminescent dosimeters. The capture gamma ray beam was extracted from a tangential beam tube of the IPEN's IEA-R1 2MW research reactor. The absorbed dose calculation was performed employing the Monte Carlo N-particle transport code (MCNP) and two methods of calculation: the simulated gamma ray flux multiplied by a dose conversion factor, and the simulated electron flux multiplied by the collision linear energy loss. The calculation results obtained by the electron transport have shown a good agreement with the experimental measurements. For deeper layers (more than 10 mm aluminum thickness), the calculation using the gamma ray flux multiplied by dose conversion factors, as well the calculation employing the electron transport, exhibit the same decreasing trade observed in experimental data, differing by a normalization factor of approximately 1.4. However, for layers nearer the material surface, the calculation using photon flux produces an overestimation of that using the electron transport as well as of the experimental results. (author)

  3. On the radiation dose to lung tissues from radon daughters

    International Nuclear Information System (INIS)

    Wise, K.N.

    1980-04-01

    The work of Harley and Pasternak on calculating dose conversion factors for radon daughters is re-examined. It is found that their estimates of the deposit of radon daughters on the lung airways are too low and the factor for converting from equilibrium activity of radon daughters on the airways to dose to basal cells is too high; these are re-calculated. However, it is shown that inter-subject variability of the depth of the basal cells leads to considerable uncertainty in the individual dose. Finally average dose conversion factors are re-calculated for atmospheres which may be charactersitic of underground mines; the dose conversion factors range from 8 mGy/WLM to 40 mGy/WLM as calculated from the Weibel lung model and from 3 mGy/WLM to 17 mGy/WLM as calculated from the Landahl lung model

  4. Factors Associated with Myelosuppression Related to Low-Dose Methotrexate Therapy for Inflammatory Rheumatic Diseases

    Science.gov (United States)

    Mori, Shunsuke; Hidaka, Michihiro; Kawakita, Toshiro; Hidaka, Toshihiko; Tsuda, Hiroyuki; Yoshitama, Tamami; Migita, Kiyoshi; Ueki, Yukitaka

    2016-01-01

    Objective Severe myelosuppression is a serious concern in the management of rheumatic disease patients receiving methotrexate (MTX) therapy. This study was intended to explore factors associated with the development of MTX-related myelosuppression and its disease severity. Methods We retrospectively examined a total of 40 cases of MTX-related myelosuppression that had been filed in the registries of participating rheumatology and hematology divisions. Data before onset were compared with those of 120 controls matched for age and sex. Cytopenia was graded according to the National Cancer Institute criteria for adverse events. Data before and at onset were compared between the severe and non-severe groups. Results Non-use of folic acid supplements, concurrent medications, and low renal function were significantly associated with the development of myelosuppression (p disease severity was not dependent on MTX doses. Serum albumin levels and folic acid supplementation are the important factors affecting the severity of MTX-related pancytopenia and neutropenia. PMID:27128679

  5. The influence of social psychological factors on behaviour, stress and dose in Chernobyl affected areas

    International Nuclear Information System (INIS)

    Murphy, M.; Allen, P.

    1998-01-01

    During the 12 years since the Chernobyl nuclear accident, people in the affected areas have lived day to day with the risks of radiation. During these 12 years many countermeasures have been applied to minimise dose and thus reduce the threat to the health of the affected populations. Some of these countermeasures are aimed at changing daily life; for example, advice and restrictions on behaviours relating to the forest, consumption of forest produce and the consumption of private milk. In order to be effective, these countermeasures require action, or compliance, on the part of the affected populations. How have people in these areas responded to this risk and to the countermeasures employed to minimise the risk? A number of social psychological factors may be involved in peoples responses to this situation, including their perceptions of threat, the perceived costs and benefits of the behaviours involved, and the influence of other people. We examine the influence of these various social psychological factors on compliance behaviour, dose, and stress related health through a survey of people in the affected areas using quantitative questionnaire measures. SPARPA or Social psychological aspects of radiation protection after accidents, is a European Commission-sponsored project (F14C-CT96-0010) involving U. Surrey, Symlog and NRPB as well as partners in the CIS. Specific objectives include: to characterise, using quantitative methods, the nature and psychological impact of countermeasures and the influence of behaviour on dose, and to develop, guidance on the implementation of countermeasures, taking account of the social and psychological context. (authors)

  6. Performance evaluation of a direct-conversion flat-panel detector system in imaging and quality assurance for a high-dose-rate 192Ir source

    Science.gov (United States)

    Miyahara, Yoshinori; Hara, Yuki; Nakashima, Hiroto; Nishimura, Tomonori; Itakura, Kanae; Inomata, Taisuke; Kitagaki, Hajime

    2018-03-01

    In high-dose-rate (HDR) brachytherapy, a direct-conversion flat-panel detector (d-FPD) clearly depicts a 192Ir source without image halation, even under the emission of high-energy gamma rays. However, it was unknown why iridium is visible when using a d-FPD. The purpose of this study was to clarify the reasons for visibility of the source core based on physical imaging characteristics, including the modulation transfer functions (MTF), noise power spectral (NPS), contrast transfer functions, and linearity of d-FPD to high-energy gamma rays. The acquired data included: x-rays, [X]; gamma rays, [γ] dual rays (X  +  γ), [D], and subtracted data for depicting the source ([D]  -  [γ]). In the quality assurance (QA) test for the positional accuracy of a source core, the coordinates of each dwelling point were compared between the planned and actual source core positions using a CT/MR-compatible ovoid applicator and a Fletcher-Williamson applicator. The profile curves of [X] and ([D]  -  [γ]) matched well on MTF and NPS. The contrast resolutions of [D] and [X] were equivalent. A strongly positive linear correlation was found between the output data of [γ] and source strength (r 2  >  0.99). With regard to the accuracy of the source core position, the largest coordinate difference (3D distance) was noted at the maximum curvature of the CT/MR-compatible ovoid and Fletcher-Williamson applicators, showing 1.74  ±  0.02 mm and 1.01  ±  0.01 mm, respectively. A d-FPD system provides high-quality images of a source, even when high-energy gamma rays are emitted to the detector, and positional accuracy tests with clinical applicators are useful in identifying source positions (source movements) within the applicator for QA.

  7. A meta-analysis of responses of canopy photosynthetic conversion efficiency to environmental factors reveals major causes of yield gap

    Science.gov (United States)

    Slattery, Rebecca A.; Ainsworth, Elizabeth A.; Ort, Donald R.

    2013-01-01

    Improving plant energy conversion efficiency (εc) is crucial for increasing food and bioenergy crop production and yields. Using a meta-analysis, the effects of greenhouse gases, weather-related stresses projected to intensify due to climate change, and management practices including inputs, shading, and intercropping on εc were statistically quantified from 140 published studies to identify where improvements would have the largest impact on closing yield gaps. Variation in the response of εc to treatment type and dosage, plant characteristics, and growth conditions were also examined. Significant mean increases in εc were caused by elevated [CO2] (20%), shade (18%), and intercropping (15%). εc increased curvilinearly up to 55% with nitrogen additions whereas phosphorus application was most beneficial at low levels. Significant decreases in εc of –8.4% due to elevated [O3], –16.8% due to water stress, and –6.5% due to foliar damage were found. A non-significant decrease in εc of –17.3% was caused by temperature stress. These results identify the need to engineer greater stress tolerance and enhanced responses to positive factors such as [CO2] and nitrogen to improve average yields and yield potential. Optimizing management strategies will also enhance the benefits possible with intercropping, shade, and pest resilience. To determine optimal practices for εc improvement, further studies should be conducted in the field since several responses were exaggerated by non-field experimental conditions. PMID:23873996

  8. Revised age-dependent doses to members of the public from intake of radionuclides using the new tissue weighting factors

    International Nuclear Information System (INIS)

    Jain, S.C.; Gupta, M.M.; Nagaratnam, A.; Reddy, A.R.; Mehta, S.C.

    1992-01-01

    ICRP 56 gave age-dependent dose coefficients to members of the public from intake of most radiologically significant radionuclides that might be released to the environment due to various human activities. It has computed effective dose equivalent (now called effective dose) from these dose coefficients utilising the tissue weighting factors as given by ICRP 26. The recent ICRP 1990 recommendations have revised the tissue weighting factors based on new information on risk estimates of fatal cancer and hereditary disorders. This change in the tissue weighting factors will subsequently affect the computation of effective dose due to intake of various radio-nuclides considered by ICRP 56. The revised effective doses for ingested as well as inhaled radionuclides have been worked out and compared from corresponding earlier values. No change was found in the case of tritiated water, organically bound tritium and 14 C. For the majority of the radionuclides, the revised effective dose was within ± 20% of the earlier values. Larger variations in effective dose were noted for radionuclides which deposit preferentially in one or two organs. (author)

  9. Ozone dosing alters the biological potential and therapeutic outcomes of plasma rich in growth factors.

    Science.gov (United States)

    Anitua, E; Zalduendo, M M; Troya, M; Orive, G

    2015-04-01

    Until now, ozone has been used in a rather empirical way. This in-vitro study investigates, for the first time, whether different ozone treatments of plasma rich in growth factors (PRGF) alter the biological properties and outcomes of this autologous platelet-rich plasma. Human plasma rich in growth factors was treated with ozone using one of the following protocols: a continuous-flow method; or a syringe method in which constant volumes of ozone and PRGF were mixed. In both cases, ozone was added before, during and after the addition of calcium chloride. Three ozone concentrations, of the therapeutic range 20, 40 and 80 μg/mL, were tested. Fibrin clot properties, growth factor content and the proliferative effect on primary osteoblasts and gingival fibroblasts were evaluated. Ozone treatment of PRGF using the continuous flow protocol impaired formation of the fibrin scaffold, drastically reduced the levels of growth factors and significantly decreased the proliferative potential of PRGF on primary osteoblasts and gingival fibroblasts. In contrast, treatment of PRGF with ozone using the syringe method, before, during and after the coagulation process, did not alter the biological outcomes of the autologous therapy. These findings suggest that ozone dose and the way that ozone combines with PRGF may alter the biological potential and therapeutic outcomes of PRGF. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Investigation of 1-cm dose equivalent for photons behind shielding materials

    International Nuclear Information System (INIS)

    Hirayama, Hideo; Tanaka, Shun-ichi

    1991-03-01

    The ambient dose equivalent at 1-cm depth, assumed equivalent to the 1-cm dose equivalent in practical dose estimations behind shielding slabs of water, concrete, iron or lead for normally incident photons having various energies was calculated by using conversion factors for a slab phantom. It was compared with the 1-cm depth dose calculated with the Monte Carlo code EGS4. It was concluded from this comparison that the ambient dose equivalent calculated by using the conversion factors for the ICRU sphere could be used for the evaluation of the 1-cm dose equivalent for the sphere phantom within 20% errors. Average and practical conversion factors are defined as the conversion factors from exposure to ambient dose equivalent in a finite slab or an infinite one, respectively. They were calculated with EGS4 and the discrete ordinates code PALLAS. The exposure calculated with simple estimation procedures such as point kernel methods can be easily converted to ambient dose equivalent by using these conversion factors. The maximum value between 1 and 30 mfp can be adopted as the conversion factor which depends only on material and incident photon energy. This gives the ambient dose equivalent on the safe side. 13 refs., 7 figs., 2 tabs

  11. Effect of physiological factors on dose due to organically bound tritium

    International Nuclear Information System (INIS)

    Trivedi, A.

    1998-01-01

    The International Commission on Radiological Protection (ICRP) recommends the understanding of the effect of age, anatomical and physiological data on the doses in order to prescribe dose coefficient for radionuclides. The published data on OBT dose fraction after acute or chronic intakes of HTO are evaluated to examine the variation of OBT dose with the age and physiology of occupational workers. (author)

  12. Final Aperture Superposition Technique applied to fast calculation of electron output factors and depth dose curves

    International Nuclear Information System (INIS)

    Faddegon, B.A.; Villarreal-Barajas, J.E.

    2005-01-01

    The Final Aperture Superposition Technique (FAST) is described and applied to accurate, near instantaneous calculation of the relative output factor (ROF) and central axis percentage depth dose curve (PDD) for clinical electron beams used in radiotherapy. FAST is based on precalculation of dose at select points for the two extreme situations of a fully open final aperture and a final aperture with no opening (fully shielded). This technique is different than conventional superposition of dose deposition kernels: The precalculated dose is differential in position of the electron or photon at the downstream surface of the insert. The calculation for a particular aperture (x-ray jaws or MLC, insert in electron applicator) is done with superposition of the precalculated dose data, using the open field data over the open part of the aperture and the fully shielded data over the remainder. The calculation takes explicit account of all interactions in the shielded region of the aperture except the collimator effect: Particles that pass from the open part into the shielded part, or visa versa. For the clinical demonstration, FAST was compared to full Monte Carlo simulation of 10x10,2.5x2.5, and 2x8 cm 2 inserts. Dose was calculated to 0.5% precision in 0.4x0.4x0.2 cm 3 voxels, spaced at 0.2 cm depth intervals along the central axis, using detailed Monte Carlo simulation of the treatment head of a commercial linear accelerator for six different electron beams with energies of 6-21 MeV. Each simulation took several hours on a personal computer with a 1.7 Mhz processor. The calculation for the individual inserts, done with superposition, was completed in under a second on the same PC. Since simulations for the pre calculation are only performed once, higher precision and resolution can be obtained without increasing the calculation time for individual inserts. Fully shielded contributions were largest for small fields and high beam energy, at the surface, reaching a maximum

  13. Transcatheter Arterial Embolization for Primary Postpartum Hemorrhage: Predictive Factors of Need for Embolic Material Conversion of Gelatin Sponge Particles to N-Butyl Cyanoacrylate

    International Nuclear Information System (INIS)

    Tanahashi, Yukichi; Goshima, Satoshi; Kondo, Hiroshi; Ando, Tomohiro; Noda, Yoshifumi; Kawada, Hiroshi; Kawai, Nobuyuki; Kotoku, Junichi; Furui, Shigeru; Matsuo, Masayuki

    2017-01-01

    PurposeTo identify predictive factors for embolic material conversion to N-butyl cyanoacrylate (NBCA) for the treatment of primary postpartum hemorrhage (PPH) after failed transcatheter arterial embolization (TAE) using gelatin sponge (GS).Materials and MethodsInstitutional review board approval was obtained. We retrospectively studied 62 consecutive women with primary PPH who underwent TAE between January 2006 and March 2015. Five of them were excluded for the following: cardiopulmonary arrest at arrival (n = 1), uterine inversion (n = 1), and hysterectomy after TAE (n = 3). Remaining 57 women (age range, 21–43 years; mean, 32.6 years) comprised study population. TAE was initially performed using GS in all cases and then converted to NBCA after two embolizations using GS with persistent hemodynamic instability or vaginal bleeding. The patients’ background, uterine height, vital signs, laboratory tests, disseminated intravascular coagulation score, and details of procedure were reviewed. Univariate and multivariate analyses were performed to determine factors related to embolic material conversion.ResultsTechnical success rate was 100%. Fourteen patients (25%) needed embolic material conversion to NBCA. Univariate analysis showed that uterine height, systolic blood pressure (sBP), and hemoglobin level were significantly related to embolic material conversion to NBCA (P = 0.029, 0.030, and 0.042). Logistic regression analysis showed that uterine height (odds ratio, 1.37; P = 0.025) and sBP (odds ratio, 0.96; P = 0.003) were associated with embolic material conversion to NBCA.ConclusionUterine height and sBP can be predictive factors for embolic material conversion to NBCA for the treatment of PPH.Level of EvidenceLevel 4, Case Control Study

  14. Transcatheter Arterial Embolization for Primary Postpartum Hemorrhage: Predictive Factors of Need for Embolic Material Conversion of Gelatin Sponge Particles to N-Butyl Cyanoacrylate

    Energy Technology Data Exchange (ETDEWEB)

    Tanahashi, Yukichi; Goshima, Satoshi, E-mail: gossy@par.odn.ne.jp [Gifu University Hospital, Department of Radiology (Japan); Kondo, Hiroshi [Teikyo University School of Medicine, Department of Radiology (Japan); Ando, Tomohiro; Noda, Yoshifumi; Kawada, Hiroshi; Kawai, Nobuyuki [Gifu University Hospital, Department of Radiology (Japan); Kotoku, Junichi [Teikyo University School of Medicine, Department of Radiological Technology, Faculty of Medical Technology (Japan); Furui, Shigeru [Teikyo University School of Medicine, Department of Radiology (Japan); Matsuo, Masayuki [Gifu University Hospital, Department of Radiology (Japan)

    2017-02-15

    PurposeTo identify predictive factors for embolic material conversion to N-butyl cyanoacrylate (NBCA) for the treatment of primary postpartum hemorrhage (PPH) after failed transcatheter arterial embolization (TAE) using gelatin sponge (GS).Materials and MethodsInstitutional review board approval was obtained. We retrospectively studied 62 consecutive women with primary PPH who underwent TAE between January 2006 and March 2015. Five of them were excluded for the following: cardiopulmonary arrest at arrival (n = 1), uterine inversion (n = 1), and hysterectomy after TAE (n = 3). Remaining 57 women (age range, 21–43 years; mean, 32.6 years) comprised study population. TAE was initially performed using GS in all cases and then converted to NBCA after two embolizations using GS with persistent hemodynamic instability or vaginal bleeding. The patients’ background, uterine height, vital signs, laboratory tests, disseminated intravascular coagulation score, and details of procedure were reviewed. Univariate and multivariate analyses were performed to determine factors related to embolic material conversion.ResultsTechnical success rate was 100%. Fourteen patients (25%) needed embolic material conversion to NBCA. Univariate analysis showed that uterine height, systolic blood pressure (sBP), and hemoglobin level were significantly related to embolic material conversion to NBCA (P = 0.029, 0.030, and 0.042). Logistic regression analysis showed that uterine height (odds ratio, 1.37; P = 0.025) and sBP (odds ratio, 0.96; P = 0.003) were associated with embolic material conversion to NBCA.ConclusionUterine height and sBP can be predictive factors for embolic material conversion to NBCA for the treatment of PPH.Level of EvidenceLevel 4, Case Control Study.

  15. EPR spectrum deconvolution and dose assessment of fossil tooth enamel using maximum likelihood common factor analysis

    International Nuclear Information System (INIS)

    Vanhaelewyn, G.; Callens, F.; Gruen, R.

    2000-01-01

    In order to determine the components which give rise to the EPR spectrum around g = 2 we have applied Maximum Likelihood Common Factor Analysis (MLCFA) on the EPR spectra of enamel sample 1126 which has previously been analysed by continuous wave and pulsed EPR as well as EPR microscopy. MLCFA yielded agreeing results on three sets of X-band spectra and the following components were identified: an orthorhombic component attributed to CO - 2 , an axial component CO 3- 3 , as well as four isotropic components, three of which could be attributed to SO - 2 , a tumbling CO - 2 and a central line of a dimethyl radical. The X-band results were confirmed by analysis of Q-band spectra where three additional isotropic lines were found, however, these three components could not be attributed to known radicals. The orthorhombic component was used to establish dose response curves for the assessment of the past radiation dose, D E . The results appear to be more reliable than those based on conventional peak-to-peak EPR intensity measurements or simple Gaussian deconvolution methods

  16. THE CO-TO-H2 CONVERSION FACTOR AND DUST-TO-GAS RATIO ON KILOPARSEC SCALES IN NEARBY GALAXIES

    International Nuclear Information System (INIS)

    Sandstrom, K. M.; Walter, F.; Leroy, A. K.; Bolatto, A. D.; Wolfire, M.; Croxall, K. V.; Crocker, A.; Draine, B. T.; Aniano, G.; Wilson, C. D.; Calzetti, D.; Kennicutt, R. C.; Galametz, M.; Donovan Meyer, J.; Usero, A.; Bigiel, F.; Brinks, E.; De Blok, W. J. G.; Dale, D.; Engelbracht, C. W.

    2013-01-01

    We present ∼kiloparsec spatial resolution maps of the CO-to-H 2 conversion factor (α CO ) and dust-to-gas ratio (DGR) in 26 nearby, star-forming galaxies. We have simultaneously solved for α CO and the DGR by assuming that the DGR is approximately constant on kiloparsec scales. With this assumption, we can combine maps of dust mass surface density, CO-integrated intensity, and H I column density to solve for both α CO and the DGR with no assumptions about their value or dependence on metallicity or other parameters. Such a study has just become possible with the availability of high-resolution far-IR maps from the Herschel key program KINGFISH, 12 CO J = (2-1) maps from the IRAM 30 m large program HERACLES, and H I 21 cm line maps from THINGS. We use a fixed ratio between the (2-1) and (1-0) lines to present our α CO results on the more typically used 12 CO J = (1-0) scale and show using literature measurements that variations in the line ratio do not affect our results. In total, we derive 782 individual solutions for α CO and the DGR. On average, α CO = 3.1 M ☉ pc –2 (K km s –1 ) –1 for our sample with a standard deviation of 0.3 dex. Within galaxies, we observe a generally flat profile of α CO as a function of galactocentric radius. However, most galaxies exhibit a lower α CO value in the central kiloparsec—a factor of ∼2 below the galaxy mean, on average. In some cases, the central α CO value can be factors of 5-10 below the standard Milky Way (MW) value of α CO, M W = 4.4 M ☉ pc –2 (K km s –1 ) –1 . While for α CO we find only weak correlations with metallicity, the DGR is well-correlated with metallicity, with an approximately linear slope. Finally, we present several recommendations for choosing an appropriate α CO for studies of nearby galaxies

  17. Comparison of effective doses using tissue-weighting factors in the 1977, 1990, and 2007 recommendations of the ICRP

    International Nuclear Information System (INIS)

    Matsunaga, Yuta; Kawaguchi, Ai; Suzuki, Shoichi

    2013-01-01

    The International Commission on Radiological Protection (ICRP) has established recommended tissue-weighting factors. Although there have been international reports on effective doses using the factors listed in the 1977, 1990, and 2007 recommendations of the ICRP, there have been no papers in Japan. The aim of this study was to evaluate effective doses using the tissue-weighting factors listed in each recommendation of the ICRP under 2011 exposure conditions in Japan. We used a human body phantom to estimate patient exposure doses during chest, abdomen, lumbar spine (anteroposterior and lateral), and head radiographs. With thermoluminescence dosimeters placed at various positions on and in the phantom, radiation doses were determined. There was little change in the effective doses to the chest and head from each recommendation. However, the effective doses recommended in 1977 were 0.2 mSv to the abdomen, 0.1 mSv to the lumbar spine anteroposteriorally, and 0.1 mSv to the lumbar spine laterally; these values are lower than those recommended in 1990 and 2007, which were 0.5 mSv to the abdomen, 0.4 mSv to the lumbar spine anteroposteriorally, and 0.6 mSv to the lumbar spine laterally. We could evaluate the effective doses using each recommendation and 2011 exposure conditions in Japan. (author)

  18. Determination of attenuation factors for mortar of barite in terms of environmental dose equivalent and effective dose

    International Nuclear Information System (INIS)

    Almeida Junior, Airton T.; Campos, L.L.R.; Araujo, F.G.S.; Santos, M.A.P.; Nogueira, M.S.

    2014-01-01

    This work addresses the characterization of barite mortars used as Xray shielding materials through the following quantities: mass attenuation coefficient, air kerma, effective dose and ambient dose - H⁎(10). The experiment was carried out with the use of the following reference qualities: RQR4, RQR6, RQR9 e RQR10, specified in accordance with norm IEC 61267: Medical diagnostic Xray equipment - radiation conditions for use in the determination of characteristics. In this study values was determined experimentally for the attenuation of the Cream barite (density 2.99g/cm 3 , collected in the state of Sao Paulo), Purple barite (density 2.95g/cm 3 , collected in the state of Bahia) and White barite (density 3.10g/cm 3 , collected in the state of Paraiba). These materials, in the form of mortar, were disposed in the form of squares namely poof bodies, whose dimensions were 10 x 10 cm and thickness ranging from 3 to 15 mm approximately. In the experimental procedure, these proof bodies were irradiated with a Pantak, model HF320 industrial X-ray apparatus. The potentials applied to the respective X-ray tube were: 60kV, 80kV, 120kV and 150kV at a constant current of 1mA. The attenuation responses in function of thickness, for each of the materials analyzed, were used to draw the attenuation and transmission curves. The efficiency of the barite studied concerning the capacity to attenuate X-ray radiation for X-ray beams ranging from 60 to 150 kV indicated

  19. Cosmic rays, gas and dust in nearby anticentre clouds. I. CO-to-H2 conversion factors and dust opacities

    Science.gov (United States)

    Remy, Q.; Grenier, I. A.; Marshall, D. J.; Casandjian, J. M.

    2017-05-01

    Aims: We aim to explore the capabilities of dust emission and γ rays for probing the properties of the interstellar medium in the nearby anti-centre region, using γ-ray observations with the Fermi Large Area Telescope (LAT), and the thermal dust optical depth inferred from Planck and IRAS observations. We also aim to study massive star-forming clouds including the well known Taurus, Auriga, Perseus, and California molecular clouds, as well as a more diffuse structure which we refer to as Cetus. In particular, we aim at quantifying potential variations in cosmic-ray density and dust properties per gas nucleon across the different gas phases and different clouds, and at measuring the CO-to-H2 conversion factor, XCO, in different environments. Methods: We have separated six nearby anti-centre clouds that are coherent in velocities and distances, from the Galactic-disc background in H I 21-cm and 12CO 2.6-mm line emission. We have jointly modelled the γ-ray intensity recorded between 0.4 and 100 GeV, and the dust optical depth τ353 at 353 GHz as a combination of H I-bright, CO-bright, and ionised gas components. The complementary information from dust emission and γ rays was used to reveal the gas not seen, or poorly traced, by H I, free-free, and 12CO emissions, namely (I) the opaque H iand diffuse H2 present in the Dark Neutral Medium at the atomic-molecular transition, and (II) the dense H2 to be added where 12CO lines saturate. Results: The measured interstellar γ-ray spectra support a uniform penetration of the cosmic rays with energies above a few GeV through the clouds, from the atomic envelopes to the 12CO-bright cores, and with a small ± 9% cloud-to-cloud dispersion in particle flux. We detect the ionised gas from the H iiregion NGC 1499 in the dust and γ-ray emissions and measure its mean electron density and temperature. We find a gradual increase in grain opacity as the gas (atomic or molecular) becomes more dense. The increase reaches a factor of

  20. On the field-to-current conversion factors for large bipolar lightning discharge events in winter thunderstorms in Japan

    Science.gov (United States)

    Chen, Long; Zhang, Qilin; Hou, Wenhao; Tao, Yulang

    2015-07-01

    In this paper we have simulated the far-field waveform characteristic of large bipolar events (LBEs) occurred in winter thunderstorms in Japan and compared the field-to-current conversion factors (FCCFs) of LBEs with that of the lightning cloud-to-ground (CG) return stroke (RS) in summer thunderstorm. As for the physical process of LBEs, Wu et al. (2014) considered that LBEs may be very similar to the typical lightning RS (RS-like process) or caused by an initial continuous current pulse (ICC-like process) in upward lightning flashes. We assume that the lightning channel length of LBEs ranges from 500 m to 1000 m, and the height of tall object struck by LBEs is from 100 m to 300 m. By using the bouncing wave model, we found that only when the injected current waveform of LBEs is characterized with a symmetric Gaussian pulse, the simulated far-field waveform of LBEs both for RS-like process and ICC-like process is similar to that observed by Wu et al. (2014). For striking tall objects with heights from 100 m and 300 m, the FCCFs of LBEs are positively correlated with its channel length and derivatives of injected current waveform, and the FCCF for RS-like process is about similar to that for ICC-like process. However, the FCCFs of LBEs are very different from lightning RS in summer thunderstorm; that is to say, the FCCFs developed for the well-known lightning RS in summer thunderstorm are not suitable for LBEs.

  1. SU-F-T-686: Considerations About Dose Protraction Factor in TCP Calculations for Prostate VMAT Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Clemente, F; Perez-Vara, C; Clavo, M [Herranz Hospital Central de la Defensa “Gomez Ulla”, Madrid (Spain)

    2016-06-15

    Purpose: Dose protraction factor should be considered in order to model the TCP calculations. Nevertheless, this study describes a brief discussion showing that the lack of its inclusion should not invalidate these calculations for prostate VMAT treatments. Methods: Dose protraction factor (G) modifies the quadratic term of the linear-quadratic expression in order to take into account the sublethal damage repair of protracting the dose delivery. If the delivery takes a short time (instantaneous), G = 1. For any other dose delivery pattern, G < 1. The Lea-Catcheside dose protraction factor for external beam radiotherapy contains terms depending of on the tissue specific repair parameter (λ) and the irradiation time (T). Expanding the exponential term using a Taylor’s series and neglecting terms of order (λT){sup 3}, the approximation leads to G = 1. The described situation occurs for 3DCRT techniques, where treatment times are about few minutes. For IMRT techniques, fraction times are prolonged compared to 3DCRT times. Wang et al. (2003) and Fowler et al. (2004) investigated the protraction effect with respect to IMRT treatments, reporting clinically significant loss in biological effect associated with IMRT delivery times. Results: Treatment times are noticeably reduced for prostate treatments using VMAT techniques. These times are comparable to 3DCRT times, leading to consider the previous approximation. Conclusion: Dose protraction factor can be approximated by G = 1 in TCP calculations for prostate treatments using VMAT techniques.

  2. Calculation methods for determining dose equivalent

    International Nuclear Information System (INIS)

    Endres, G.W.R.; Tanner, J.E.; Scherpelz, R.I.; Hadlock, D.E.

    1987-11-01

    A series of calculations of neutron fluence as a function of energy in an anthropomorphic phantom was performed to develop a system for determining effective dose equivalent for external radiation sources. Critical organ dose equivalents are calculated and effective dose equivalents are determined using ICRP-26 [1] methods. Quality factors based on both present definitions and ICRP-40 definitions are used in the analysis. The results of these calculations are presented and discussed. The effective dose equivalent determined using ICRP-26 methods is significantly smaller than the dose equivalent determined by traditional methods. No existing personnel dosimeter or health physics instrument can determine effective dose equivalent. At the present time, the conversion of dosimeter response to dose equivalent is based on calculations for maximal or ''cap'' values using homogeneous spherical or cylindrical phantoms. The evaluated dose equivalent is, therefore, a poor approximation of the effective dose equivalent as defined by ICRP Publication 26. 3 refs., 2 figs., 1 tab

  3. Protection by GDNF and other trophic factors against the dopamine-depleting effects of neurotoxic doses of methamphetamine.

    Science.gov (United States)

    Cass, Wayne A; Peters, Laura E; Harned, Michael E; Seroogy, Kim B

    2006-08-01

    Repeated methamphetamine (METH) administration to animals can result in long-lasting decreases in striatal dopamine (DA) content. It has previously been shown that glial cell line-derived neurotrophic factor (GDNF) can reduce the DA-depleting effects of neurotoxic doses of METH. However, there are several other trophic factors that are protective against dopaminergic toxins. Thus, the present experiments further investigated the protective effect of GDNF as well as the protective effects of several other trophic factors. Male Fischer-344 rats were given an intracerebral injection of trophic factor (2-10 microg) 1 day before METH (5 mg/kg, s.c., 4 injections at 2-h intervals). Seven days later DA levels in the striatum were measured using high-performance liquid chromatography (HPLC). Initial experiments indicated that only intrastriatal GDNF, and not intranigral GDNF, was protective. Thereafter, all other trophic factors were administered into the striatum. Members of the GDNF family (GDNF, neurturin, and artemin) all provided significant protection against the DA-depleting effects of METH, with GDNF providing the greatest protection. Brain-derived neurotrophic factor, neurotrophin-3, acidic fibroblast growth factor, basic fibroblast growth factor, ciliary neurotrophic factor, transforming growth factor-alpha (TGF-alpha), heregulin beta1 (HRG-beta1), and amphiregulin (AR) provided no significant protection at the doses examined. These results suggest that the GDNF family of trophic factors can provide significant protection against the DA-depleting effects of neurotoxic doses of METH.

  4. Modeling of Body Weight Metrics for Effective and Cost-Efficient Conventional Factor VIII Dosing in Hemophilia A Prophylaxis

    Directory of Open Access Journals (Sweden)

    Alanna McEneny-King

    2017-10-01

    Full Text Available The total body weight-based dosing strategy currently used in the prophylactic treatment of hemophilia A may not be appropriate for all populations. The assumptions that guide weight-based dosing are not valid in overweight and obese populations, resulting in overdosing and ineffective resource utilization. We explored different weight metrics including lean body weight, ideal body weight, and adjusted body weight to determine an alternative dosing strategy that is both safe and resource-efficient in normal and overweight/obese adult patients. Using a validated population pharmacokinetic model, we simulated a variety of dosing regimens using different doses, weight metrics, and frequencies; we also investigated the implications of assuming various levels of endogenous factor production. Ideal body weight performed the best across all of the regimens explored, maintaining safety while moderating resource consumption for overweight and obese patients.

  5. Prediction of soil urea conversion and quantification of the importance degrees of influencing factors through a new combinatorial model based on cluster method and artificial neural network.

    Science.gov (United States)

    Lei, Tao; Guo, Xianghong; Sun, Xihuan; Ma, Juanjuan; Zhang, Shaowen; Zhang, Yong

    2018-05-01

    Quantitative prediction of soil urea conversion is crucial in determining the mechanism of nitrogen transformation and understanding the dynamics of soil nutrients. This study aimed to establish a combinatorial prediction model (MCA-F-ANN) for soil urea conversion and quantify the relative importance degrees (RIDs) of influencing factors with the MCA-F-ANN method. Data samples were obtained from laboratory culture experiments, and soil nitrogen content and physicochemical properties were measured every other day. Results showed that when MCA-F-ANN was used, the mean-absolute-percent error values of NH 4 + -N, NO 3 - -N, and NH 3 contents were 3.180%, 2.756%, and 3.656%, respectively. MCA-F-ANN predicted urea transformation under multi-factor coupling conditions more accurately than traditional models did. The RIDs of reaction time (RT), electrical conductivity (EC), temperature (T), pH, nitrogen application rate (F), and moisture content (W) were 32.2%-36.5%, 24.0%-28.9%, 12.8%-15.2%, 9.8%-12.5%, 7.8%-11.0%, and 3.5%-6.0%, respectively. The RIDs of the influencing factors in a descending order showed the pattern RT > EC > T > pH > F > W. RT and EC were the key factors in the urea conversion process. The prediction accuracy of urea transformation process was improved, and the RIDs of the influencing factors were quantified. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Gene array analysis of neural crest cells identifies transcription factors necessary for direct conversion of embryonic fibroblasts into neural crest cells

    Directory of Open Access Journals (Sweden)

    Tsutomu Motohashi

    2016-03-01

    Full Text Available Neural crest cells (NC cells are multipotent cells that emerge from the edge of the neural folds and migrate throughout the developing embryo. Although the gene regulatory network for generation of NC cells has been elucidated in detail, it has not been revealed which of the factors in the network are pivotal to directing NC identity. In this study we analyzed the gene expression profile of a pure NC subpopulation isolated from Sox10-IRES-Venus mice and investigated whether these genes played a key role in the direct conversion of Sox10-IRES-Venus mouse embryonic fibroblasts (MEFs into NC cells. The comparative molecular profiles of NC cells and neural tube cells in 9.5-day embryos revealed genes including transcription factors selectively expressed in developing trunk NC cells. Among 25 NC cell-specific transcription factor genes tested, SOX10 and SOX9 were capable of converting MEFs into SOX10-positive (SOX10+ cells. The SOX10+ cells were then shown to differentiate into neurons, glial cells, smooth muscle cells, adipocytes and osteoblasts. These SOX10+ cells also showed limited self-renewal ability, suggesting that SOX10 and SOX9 directly converted MEFs into NC cells. Conversely, the remaining transcription factors, including well-known NC cell specifiers, were unable to convert MEFs into SOX10+ NC cells. These results suggest that SOX10 and SOX9 are the key factors necessary for the direct conversion of MEFs into NC cells.

  7. Determination of Entrance Skin Doses and Organ Doses for Medical X Ray Examinations

    International Nuclear Information System (INIS)

    Tung, C.J.; Cheng, C.Y.; Chao, T.C.; Tsai, H.Y.

    1999-01-01

    A national survey of patient doses for diagnostic X ray radiographs is planned in Taiwan. Entrance skin doses and organ doses for all installed X ray machines will be investigated. A pilot study has been carried out for the national survey to develop a protocol for the dose assessment. Entrance skin doses and organ doses were measured by thermoluminescence dosemeters and calculated by Monte Carlo simulations for several X ray examinations. The conversion factor from free air entrance absorbed dose to entrance skin dose was derived. A formula for the computation of entrance skin doses from inputs of kV p , mA.s, source to skin distance, aluminium filtration, and generator rectifying was constructed. Organ doses were measured using a RANDO phantom and calculated using a mathematical phantom. All data will be passed to the Atomic Energy Council for developing a programme of national survey and regulatory controls for diagnostic X ray examinations. (author)

  8. Assessment of individual dose utilization vs. physician prescribing recommendations for recombinant activated factor VII (rFVIIa) in paediatric and adult patients with congenital haemophilia and alloantibody inhibitors (CHwI): the Dosing Observational Study in Hemophilia (DOSE).

    Science.gov (United States)

    Gruppo, R A; Kessler, C M; Neufeld, E J; Cooper, D L

    2013-07-01

    Recent data from the Dosing Observational Study in Hemophilia diary study has described home treatment with recombinant activated factor VII (rFVIIa) in congenital haemophilia with inhibitors (CHwI). The current analysis compares prescribed and patient/caregiver-reported rFVIIa administration in paediatric and adult CHwI patients in this study. Patients with ≥ 4 bleeding episodes within a 3-month period prescribed rFVIIa as first-line therapy for bleeding episodes were eligible. Patients/caregivers completed a diary for ≥ 90 days or until the patient experienced four bleeds. Initial, total and mean rFVIIa doses reported for each bleeding episode were calculated and compared with the physician-prescribed doses. Of 52 enrolled patients (25 children; 27 adults), 39 (75%) completed the study. Children and adults had similar mean durations of bleeding episodes. Both patient groups were administered higher initial rFVIIa doses for joint bleeds than prescribed: median (range) 215.2 (74.1-400.0) mcg kg(-1) vs. 200.0 (61.0-270.0) mcg kg(-1) for children, and 231.3 (59.3-379.7) mcg kg(-1) vs. 123.0 (81.0-289.0) mcg kg(-1) for adults. The median infused dose for joint bleeds was higher in adults than children (175.2 vs. 148.0 mcg kg(-1) ), but children received significantly more doses per joint bleed than adults (median 6.5 vs. 3.0). The median total dose per joint bleed was higher in children than adults (1248.7 vs. 441.6). For children and adults, both initial and additional doses administered for bleeds were higher than prescribed. Children received higher total doses per bleed due to an increased number of infusions per bleed. © 2013 John Wiley & Sons Ltd.

  9. SPECIAL CONSIDERATIONS REGARDING WARFARIN DOSE TITRATION IN PATIENTS WITH ATRIAL FIBRILLATION DEPENDING ON CLINICAL FACTORS

    OpenAIRE

    E. L. Artanova; E. V. Saleeva; I. M. Sokolov; Y. G. Shvarts

    2011-01-01

    Aim. To study the relations of clinical characteristics and individual warfarin dose titration in patients with atrial fibrillation. Material and methods. Period of warfarin dose titration was analyzed in 68 patients with atrial fibrillation due to ischemic heart disease. Adjusted warfarin dose in milligram, duration of dose titration in days and maximal international normalized ratio (INR) were taken into account. Sex, age, history of myocardial infarction and stroke, concomitant diseases, a...

  10. Objective factors affecting the image quality of low-dose cranial CT of infant

    International Nuclear Information System (INIS)

    Xie Na; Gan Yungen; Wang Hongwei; Zeng Hongwu; Cao Weiguo; Sun Longwei

    2010-01-01

    Objective: To investigate the objective factors that affect the image quality of infant cranial CT using different mAs. Materials and Methods: Ninety infants were divided into three groups randomly. The maximum anteroposterior diameter (MAPD) of skull of each infant was measured. Three reference levels, cerebellar, basal ganglia and centrum semiovale levels were selected respectively. Only one level was studied in each group and scanned with 150, 100 and 80 mAs. The subjective quality grade and the objective noise of all images were recorded and analysed statistically. Results: The average MAPD of ninety patients was (148.0±17.4) mm. On the cerebellar level, the subjective quality grade was lower than the other two levels, which were 6.3%, 9.4% and 22.9% respectively when mAs were 150, 100 and 80 mAs. Both quality grade of image and objective noise were significantly correlated with MAPD. Conclusions: The inherent high noise of cerebellar level and MAPD were the objective factors that affect the image quality of low-dose cranial CT of infant. (authors)

  11. Changes in pulmonary function and influencing factors after high-dose intrathoracic radio(chemo)therapy

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Christina [University Clinic Giessen and Marburg, Clinic for Radiotherapy and Radiation Oncology, Marburg (Germany); Ruppiner Kliniken GmbH, Clinic for Radiotherapy and Radiation Oncology, Neuruppin (Germany); Engenhart-Cabillic, Rita; Vorwerk, Hilke [University Clinic Giessen and Marburg, Clinic for Radiotherapy and Radiation Oncology, Marburg (Germany); Schmidt, Michael; Huhnt, Winfried; Blank, Eyck; Sidow, Dietrich; Buchali, Andre [Ruppiner Kliniken GmbH, Clinic for Radiotherapy and Radiation Oncology, Neuruppin (Germany)

    2017-02-15

    Using prospectively collected patient-related, dose-related, and pulmonary function test (PFT) data before radiotherapy (RT) and at several follow-up visits after RT, the time course of PFT changes after high-dose radio(chemo)therapy and influencing factors were analyzed. From April 2012 to October 2015, 81 patients with non-small-cell lung carcinoma (NSCLC), small cell lung carcinoma (SCLC), or esophageal carcinoma where treated with high-dose radio(chemo)therapy. PFT data were collected before treatment and 6 weeks, 12 weeks, and 6 months after RT. The influence of patient- and treatment-related factors on PFT was analyzed. Mean forced expiratory volume in 1 s (FEV1) constantly declined during f