Science.gov

Sample records for environment dose assessment

  1. Radioactivity in food and the environment: calculations of UK radiation doses using integrated assessment methods.

    PubMed

    Camplin, W C; Brownless, G P; Round, G D; Winpenny, K; Hunt, G J

    2002-12-01

    A new method for estimating radiation doses to UK critical groups is proposed for discussion. Amongst others, the Food Standards Agency (FSA) and the Scottish Environment Protection Agency (SEPA) undertake surveillance of UK food and the environment as a check on the effect of discharges of radioactive wastes. Discharges in gaseous and liquid form are made under authorisation by the Environment Agency and SEPA under powers in the Radioactive Substance Act. Results of surveillance by the FSA and SEPA are published in the Radioactivity in Food and the Environment (RIFE) report series. In these reports, doses to critical groups are normally estimated separately for gaseous and liquid discharge pathways. Simple summation of these doses would tend to overestimate doses actually received. Three different methods of combining the effects of both types of discharge in an integrated assessment are considered and ranked according to their ease of application, transparency, scientific rigour and presentational issues. A single integrated assessment method is then chosen for further study. Doses are calculated for surveillance data for the calendar year 2000 and compared with those from the existing RIFE method.

  2. Simulation of Earth-Moon-Mars Environments for the Assessment of Organ Doses

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Schwadron, Nathan; Townsend, Lawrence W.; Cucinotta, Francis A.

    2010-01-01

    Space radiation environments for historically large solar particle events (SPE) and galactic cosmic rays (GCR) at solar minimum and solar maximum are simulated in order to characterize exposures to radio-sensitive organs for missions to low-Earth orbit (LEO), moon, and Mars. Primary and secondary particles for SPE and GCR are transported through the respective atmosphere of Earth or Mars, space vehicle, and astronaut s body tissues using the HZETRN/QMSFRG computer code. In LEO, exposures are reduced compared to deep space because particles are deflected by the Earth s magnetic field and absorbed by the solid body of the Earth. Geomagnetic transmission function as a function of altitude was applied for the particle flux of charged particles, and the shift or the organ exposures to higher velocity or lower stopping powers compared to those in deep space were analyzed. In the transport through Mars atmosphere, a vertical distribution of atmospheric thickness was calculated from the temperature and pressure data of Mars Global Surveyor, and the directional cosine distribution was implemented to describe the spherically distributed atmospheric distance along the slant path at each altitude. The resultant directional shielding by Mars atmosphere at solar minimum and solar maximum was used for the particle flux simulation at various altitudes on the Martian surface. Finally, atmospheric shielding was coupled with vehicle and body shielding for organ dose estimates. We made predictions of radiation dose equivalents and evaluated acute symptoms at LEO, moon, and Mars at solar minimum and solar maximum.

  3. Simulation of Earth-Moon-Mars Environments for the Assessment of Organ Doses

    NASA Astrophysics Data System (ADS)

    Kim, M. Y.; Schwadron, N. A.; Townsend, L.; Cucinotta, F. A.

    2010-12-01

    Space radiation environments for historically large solar particle events (SPE) and galactic cosmic rays (GCR) at solar minimum and solar maximum are simulated in order to characterize exposures to radio-sensitive organs for missions to low-Earth orbit (LEO), moon, and Mars. Primary and secondary particles for SPE and GCR are transported through the respective atmosphere of Earth or Mars, space vehicle, and astronaut’s body tissues using the HZETRN/QMSFRG computer code. In LEO, exposures are reduced compared to deep space because particles are deflected by the Earth’s magnetic field and absorbed by the solid body of the Earth. Geomagnetic transmission function as a function of altitude was applied for the particle flux of charged particles, and the shift of the organ exposures to higher velocity or lower stopping powers compared to those in deep space was analyzed. In the transport through Mars atmosphere, a vertical distribution of atmospheric thickness was calculated from the temperature and pressure data of Mars Global Surveyor, and the directional cosine distribution was implemented to describe the spherically distributed atmospheric distance along the slant path at each altitude. The resultant directional shielding by Mars atmosphere at solar minimum and solar maximum was used for the particle flux simulation at various altitudes on the Martian surface. Finally, atmospheric shielding was coupled with vehicle and body shielding for organ dose estimates. We made predictions of radiation dose equivalents and evaluated acute symptoms at LEO, moon, and Mars at solar minimum and solar maximum.

  4. Hot particles in the environment: assessment of dose and health detriment.

    PubMed

    Burkart, W; Linder, H

    1987-01-01

    Hot particles, highly radioactive particles made up of fission products or actinides and being small enough to become airborne, defy many of the dose models and risk concepts in use by the health physics community. At environmental exposures, both on the level of populations and tissues, dose distributions become very skewed; only few persons or tissue cells being exposed at correspondingly higher levels. Fallout from Chernobyl showed a numerically small subfraction of the aerosol particles containing activities of up to 10 kBq 103-ruthenium or up to 0.3 Bq 242-curium in single particles. The implications of these hot particles on the dosimetry after uptake are great since the locally accumulated dose, for example in the pulmonary region, may reach up to 10 MSv. For inhalation as well as for ingestion, theoretical considerations predict a decrease in the effectiveness of particulate radioactivity as compared to monomeric activity. This hypothesis is also supported by experimental and epidemiological evidence from the examination of the radiation effects of particulate alpha-emitters deposited in the lung.

  5. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead

    PubMed Central

    Goodson, William H.; Lowe, Leroy; Carpenter, David O.; Gilbertson, Michael; Manaf Ali, Abdul; Lopez de Cerain Salsamendi, Adela; Lasfar, Ahmed; Carnero, Amancio; Azqueta, Amaya; Amedei, Amedeo; Charles, Amelia K.; Collins, Andrew R.; Ward, Andrew; Salzberg, Anna C.; Colacci, Anna Maria; Olsen, Ann-Karin; Berg, Arthur; Barclay, Barry J.; Zhou, Binhua P.; Blanco-Aparicio, Carmen; Baglole, Carolyn J.; Dong, Chenfang; Mondello, Chiara; Hsu, Chia-Wen; Naus, Christian C.; Yedjou, Clement; Curran, Colleen S.; Laird, Dale W.; Koch, Daniel C.; Carlin, Danielle J.; Felsher, Dean W.; Roy, Debasish; Brown, Dustin G.; Ratovitski, Edward; Ryan, Elizabeth P.; Corsini, Emanuela; Rojas, Emilio; Moon, Eun-Yi; Laconi, Ezio; Marongiu, Fabio; Al-Mulla, Fahd; Chiaradonna, Ferdinando; Darroudi, Firouz; Martin, Francis L.; Van Schooten, Frederik J.; Goldberg, Gary S.; Wagemaker, Gerard; Nangami, Gladys N.; Calaf, Gloria M.; Williams, Graeme P.; Wolf, Gregory T.; Koppen, Gudrun; Brunborg, Gunnar; Lyerly, H. Kim; Krishnan, Harini; Ab Hamid, Hasiah; Yasaei, Hemad; Sone, Hideko; Kondoh, Hiroshi; Salem, Hosni K.; Hsu, Hsue-Yin; Park, Hyun Ho; Koturbash, Igor; Miousse, Isabelle R.; Scovassi, A.Ivana; Klaunig, James E.; Vondráček, Jan; Raju, Jayadev; Roman, Jesse; Wise, John Pierce; Whitfield, Jonathan R.; Woodrick, Jordan; Christopher, Joseph A.; Ochieng, Josiah; Martinez-Leal, Juan Fernando; Weisz, Judith; Kravchenko, Julia; Sun, Jun; Prudhomme, Kalan R.; Narayanan, Kannan Badri; Cohen-Solal, Karine A.; Moorwood, Kim; Gonzalez, Laetitia; Soucek, Laura; Jian, Le; D’Abronzo, Leandro S.; Lin, Liang-Tzung; Li, Lin; Gulliver, Linda; McCawley, Lisa J.; Memeo, Lorenzo; Vermeulen, Louis; Leyns, Luc; Zhang, Luoping; Valverde, Mahara; Khatami, Mahin; Romano, Maria Fiammetta; Chapellier, Marion; Williams, Marc A.; Wade, Mark; Manjili, Masoud H.; Lleonart, Matilde E.; Xia, Menghang; Gonzalez Guzman, Michael J.; Karamouzis, Michalis V.; Kirsch-Volders, Micheline; Vaccari, Monica; Kuemmerle, Nancy B.; Singh, Neetu; Cruickshanks, Nichola; Kleinstreuer, Nicole; van Larebeke, Nik; Ahmed, Nuzhat; Ogunkua, Olugbemiga; Krishnakumar, P.K.; Vadgama, Pankaj; Marignani, Paola A.; Ghosh, Paramita M.; Ostrosky-Wegman, Patricia; Thompson, Patricia A.; Dent, Paul; Heneberg, Petr; Darbre, Philippa; Leung, Po Sing; Nangia-Makker, Pratima; Cheng, Qiang (Shawn); Robey, R.Brooks; Al-Temaimi, Rabeah; Roy, Rabindra; Andrade-Vieira, Rafaela; Sinha, Ranjeet K.; Mehta, Rekha; Vento, Renza; Di Fiore, Riccardo; Ponce-Cusi, Richard; Dornetshuber-Fleiss, Rita; Nahta, Rita; Castellino, Robert C.; Palorini, Roberta; Hamid, Roslida A.; Langie, Sabine A.S.; Eltom, Sakina E.; Brooks, Samira A.; Ryeom, Sandra; Wise, Sandra S.; Bay, Sarah N.; Harris, Shelley A.; Papagerakis, Silvana; Romano, Simona; Pavanello, Sofia; Eriksson, Staffan; Forte, Stefano; Casey, Stephanie C.; Luanpitpong, Sudjit; Lee, Tae-Jin; Otsuki, Takemi; Chen, Tao; Massfelder, Thierry; Sanderson, Thomas; Guarnieri, Tiziana; Hultman, Tove; Dormoy, Valérian; Odero-Marah, Valerie; Sabbisetti, Venkata; Maguer-Satta, Veronique; Rathmell, W.Kimryn; Engström, Wilhelm; Decker, William K.; Bisson, William H.; Rojanasakul, Yon; Luqmani, Yunus; Chen, Zhenbang; Hu, Zhiwei

    2015-01-01

    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety ‘Mode of Action’ framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology. PMID:26106142

  6. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

    PubMed

    Goodson, William H; Lowe, Leroy; Carpenter, David O; Gilbertson, Michael; Manaf Ali, Abdul; Lopez de Cerain Salsamendi, Adela; Lasfar, Ahmed; Carnero, Amancio; Azqueta, Amaya; Amedei, Amedeo; Charles, Amelia K; Collins, Andrew R; Ward, Andrew; Salzberg, Anna C; Colacci, Annamaria; Olsen, Ann-Karin; Berg, Arthur; Barclay, Barry J; Zhou, Binhua P; Blanco-Aparicio, Carmen; Baglole, Carolyn J; Dong, Chenfang; Mondello, Chiara; Hsu, Chia-Wen; Naus, Christian C; Yedjou, Clement; Curran, Colleen S; Laird, Dale W; Koch, Daniel C; Carlin, Danielle J; Felsher, Dean W; Roy, Debasish; Brown, Dustin G; Ratovitski, Edward; Ryan, Elizabeth P; Corsini, Emanuela; Rojas, Emilio; Moon, Eun-Yi; Laconi, Ezio; Marongiu, Fabio; Al-Mulla, Fahd; Chiaradonna, Ferdinando; Darroudi, Firouz; Martin, Francis L; Van Schooten, Frederik J; Goldberg, Gary S; Wagemaker, Gerard; Nangami, Gladys N; Calaf, Gloria M; Williams, Graeme; Wolf, Gregory T; Koppen, Gudrun; Brunborg, Gunnar; Lyerly, H Kim; Krishnan, Harini; Ab Hamid, Hasiah; Yasaei, Hemad; Sone, Hideko; Kondoh, Hiroshi; Salem, Hosni K; Hsu, Hsue-Yin; Park, Hyun Ho; Koturbash, Igor; Miousse, Isabelle R; Scovassi, A Ivana; Klaunig, James E; Vondráček, Jan; Raju, Jayadev; Roman, Jesse; Wise, John Pierce; Whitfield, Jonathan R; Woodrick, Jordan; Christopher, Joseph A; Ochieng, Josiah; Martinez-Leal, Juan Fernando; Weisz, Judith; Kravchenko, Julia; Sun, Jun; Prudhomme, Kalan R; Narayanan, Kannan Badri; Cohen-Solal, Karine A; Moorwood, Kim; Gonzalez, Laetitia; Soucek, Laura; Jian, Le; D'Abronzo, Leandro S; Lin, Liang-Tzung; Li, Lin; Gulliver, Linda; McCawley, Lisa J; Memeo, Lorenzo; Vermeulen, Louis; Leyns, Luc; Zhang, Luoping; Valverde, Mahara; Khatami, Mahin; Romano, Maria Fiammetta; Chapellier, Marion; Williams, Marc A; Wade, Mark; Manjili, Masoud H; Lleonart, Matilde E; Xia, Menghang; Gonzalez, Michael J; Karamouzis, Michalis V; Kirsch-Volders, Micheline; Vaccari, Monica; Kuemmerle, Nancy B; Singh, Neetu; Cruickshanks, Nichola; Kleinstreuer, Nicole; van Larebeke, Nik; Ahmed, Nuzhat; Ogunkua, Olugbemiga; Krishnakumar, P K; Vadgama, Pankaj; Marignani, Paola A; Ghosh, Paramita M; Ostrosky-Wegman, Patricia; Thompson, Patricia A; Dent, Paul; Heneberg, Petr; Darbre, Philippa; Sing Leung, Po; Nangia-Makker, Pratima; Cheng, Qiang Shawn; Robey, R Brooks; Al-Temaimi, Rabeah; Roy, Rabindra; Andrade-Vieira, Rafaela; Sinha, Ranjeet K; Mehta, Rekha; Vento, Renza; Di Fiore, Riccardo; Ponce-Cusi, Richard; Dornetshuber-Fleiss, Rita; Nahta, Rita; Castellino, Robert C; Palorini, Roberta; Abd Hamid, Roslida; Langie, Sabine A S; Eltom, Sakina E; Brooks, Samira A; Ryeom, Sandra; Wise, Sandra S; Bay, Sarah N; Harris, Shelley A; Papagerakis, Silvana; Romano, Simona; Pavanello, Sofia; Eriksson, Staffan; Forte, Stefano; Casey, Stephanie C; Luanpitpong, Sudjit; Lee, Tae-Jin; Otsuki, Takemi; Chen, Tao; Massfelder, Thierry; Sanderson, Thomas; Guarnieri, Tiziana; Hultman, Tove; Dormoy, Valérian; Odero-Marah, Valerie; Sabbisetti, Venkata; Maguer-Satta, Veronique; Rathmell, W Kimryn; Engström, Wilhelm; Decker, William K; Bisson, William H; Rojanasakul, Yon; Luqmani, Yunus; Chen, Zhenbang; Hu, Zhiwei

    2015-06-01

    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology. © The Author 2015. Published by Oxford University Press.

  7. Utirik Atoll Dose Assessment

    SciTech Connect

    Robison, W.L.; Conrado, C.L.; Bogen, K.T

    1999-10-06

    On March 1, 1954, radioactive fallout from the nuclear test at Bikini Atoll code-named BRAVO was deposited on Utirik Atoll which lies about 187 km (300 miles) east of Bikini Atoll. The residents of Utirik were evacuated three days after the fallout started and returned to their atoll in May 1954. In this report we provide a final dose assessment for current conditions at the atoll based on extensive data generated from samples collected in 1993 and 1994. The estimated population average maximum annual effective dose using a diet including imported foods is 0.037 mSv y{sup -1} (3.7 mrem y{sup -1}). The 95% confidence limits are within a factor of three of their population average value. The population average integrated effective dose over 30-, 50-, and 70-y is 0.84 mSv (84, mrem), 1.2 mSv (120 mrem), and 1.4 mSv (140 mrem), respectively. The 95% confidence limits on the population-average value post 1998, i.e., the 30-, 50-, and 70-y integral doses, are within a factor of two of the mean value and are independent of time, t, for t > 5 y. Cesium-137 ({sup 137}Cs) is the radionuclide that contributes most of this dose, mostly through the terrestrial food chain and secondarily from external gamma exposure. The dose from weapons-related radionuclides is very low and of no consequence to the health of the population. The annual background doses in the U. S. and Europe are 3.0 mSv (300 mrem), and 2.4 mSv (240 mrem), respectively. The annual background dose in the Marshall Islands is estimated to be 1.4 mSv (140 mrem). The total estimated combined Marshall Islands background dose plus the weapons-related dose is about 1.5 mSv y{sup -1} (150 mrem y{sup -1}) which can be directly compared to the annual background effective dose of 3.0 mSv y{sup -1} (300 mrem y{sup -1}) for the U. S. and 2.4 mSv y{sup -1} (240 mrem y{sup -1}) for Europe. Moreover, the doses listed in this report are based only on the radiological decay of {sup 137}Cs (30.1 y half-life) and other

  8. Assessment of effectiveness of geologic isolation systems. ARRRG and FOOD: computer programs for calculating radiation dose to man from radionuclides in the environment

    SciTech Connect

    Napier, B.A.; Roswell, R.L.; Kennedy, W.E. Jr.; Strenge, D.L.

    1980-06-01

    The computer programs ARRRG and FOOD were written to facilitate the calculation of internal radiation doses to man from the radionuclides in the environment and external radiation doses from radionuclides in the environment. Using ARRRG, radiation doses to man may be calculated for radionuclides released to bodies of water from which people might obtain fish, other aquatic foods, or drinking water, and in which they might fish, swim or boat. With the FOOD program, radiation doses to man may be calculated from deposition on farm or garden soil and crops during either an atmospheric or water release of radionuclides. Deposition may be either directly from the air or from irrigation water. Fifteen crop or animal product pathways may be chosen. ARRAG and FOOD doses may be calculated for either a maximum-exposed individual or for a population group. Doses calculated are a one-year dose and a committed dose from one year of exposure. The exposure is usually considered as chronic; however, equations are included to calculate dose and dose commitment from acute (one-time) exposure. The equations for calculating internal dose and dose commitment are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and Maximum Permissible Concentration (MPC) of each radionuclide. The radiation doses from external exposure to contaminated farm fields or shorelines are calculated assuming an infinite flat plane source of radionuclides. A factor of two is included for surface roughness. A modifying factor to compensate for finite extent is included in the shoreline calculations.

  9. [About Dose-Effect Relationship in the Environment Radiation Protection].

    PubMed

    Udalova, A A

    2015-01-01

    One of the most important stages in the development of a methodology for the environment radiation protection is the assessment and justification of critical radiation exposure levels for ecosystem components. In this study application of the approach for critical dose level estimation is demonstrated on the example of the data about ionizing radiation effect on reproduction and survival of agricultural plants after acute and chronic exposures. Influence of the type of dose-effect relationship on the estimated values of the critical doses and dose rates is studied using three models (linear, logarithmic and logistic). The findings obtained do not provide any robust recommendations in favor of one of the three tested functions. The models of dose-effect relationship (threshold or non-threshold) and types of radiation-induced effects (stochastic and deterministic) are discussed from the viewpoint of developing a system for radiation protection of human and non-human biota.

  10. Assessment of dose during an SGTR

    SciTech Connect

    Adams, J.P.

    1993-01-01

    The Nuclear Regulatory Commission requires utilities to determine the response of a pressurized water reactor to a steam generator tube rupture (SGTR) as part of the safety analysis for the plant. The SGTR analysis includes assumptions regarding the iodine concentration in the reactor coolant system (RCS) due to iodine spikes, primary flashing and bypass fractions, and iodine partitioning in the secondary coolant system (SCS). Experimental and analytical investigations have recently been completed wherein these assumptions were tested to determine whether and to what degree they were conservative (that is, whether they result in a calculated iodine source term/dose that is at least as large or larger than that expected during an actual event). The current study has the objective to assess the overall effects of the results of these investigations on the calculated iodine dose to the environment during an SGTR. To assist in this study, a computer program, DOSE, was written. This program uses a simple, non-mechanistic model to calculate the iodine source term to the environment during an SGTR as a function of water mass inventories and flow rates and iodine concentrations in the RCS and SCS. The principal conclusion of this study is that the iodine concentration in the RCS is the dominant parameter, due to the dominance of primary flashing on the iodine source term.

  11. REMEDIATION FACILITY WORKER DOSE ASSESSMENT

    SciTech Connect

    V. Arakali; E. Faillace

    2004-02-27

    The purpose of this design calculation is to estimate radiation doses received by personnel in the Remediation Facility performing operations to receive, prepare, open, repair, recover, disposition, and correct off-normal and non-standard conditions with casks, canisters, spent nuclear fuel (SNF) assemblies, and waste packages (WP). The specific scope of work contained in this calculation covers both collective doses and individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation. The results of this calculation will be used to support the design of the Remediation Facility and provide occupational dose estimates for the License Application.

  12. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: focus on the cancer hallmark of tumor angiogenesis.

    PubMed

    Hu, Zhiwei; Brooks, Samira A; Dormoy, Valérian; Hsu, Chia-Wen; Hsu, Hsue-Yin; Lin, Liang-Tzung; Massfelder, Thierry; Rathmell, W Kimryn; Xia, Menghang; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Brown, Dustin G; Prudhomme, Kalan R; Colacci, Annamaria; Hamid, Roslida A; Mondello, Chiara; Raju, Jayadev; Ryan, Elizabeth P; Woodrick, Jordan; Scovassi, A Ivana; Singh, Neetu; Vaccari, Monica; Roy, Rabindra; Forte, Stefano; Memeo, Lorenzo; Salem, Hosni K; Lowe, Leroy; Jensen, Lasse; Bisson, William H; Kleinstreuer, Nicole

    2015-06-01

    One of the important 'hallmarks' of cancer is angiogenesis, which is the process of formation of new blood vessels that are necessary for tumor expansion, invasion and metastasis. Under normal physiological conditions, angiogenesis is well balanced and controlled by endogenous proangiogenic factors and antiangiogenic factors. However, factors produced by cancer cells, cancer stem cells and other cell types in the tumor stroma can disrupt the balance so that the tumor microenvironment favors tumor angiogenesis. These factors include vascular endothelial growth factor, endothelial tissue factor and other membrane bound receptors that mediate multiple intracellular signaling pathways that contribute to tumor angiogenesis. Though environmental exposures to certain chemicals have been found to initiate and promote tumor development, the role of these exposures (particularly to low doses of multiple substances), is largely unknown in relation to tumor angiogenesis. This review summarizes the evidence of the role of environmental chemical bioactivity and exposure in tumor angiogenesis and carcinogenesis. We identify a number of ubiquitous (prototypical) chemicals with disruptive potential that may warrant further investigation given their selectivity for high-throughput screening assay targets associated with proangiogenic pathways. We also consider the cross-hallmark relationships of a number of important angiogenic pathway targets with other cancer hallmarks and we make recommendations for future research. Understanding of the role of low-dose exposure of chemicals with disruptive potential could help us refine our approach to cancer risk assessment, and may ultimately aid in preventing cancer by reducing or eliminating exposures to synergistic mixtures of chemicals with carcinogenic potential.

  13. Integrated retrospective radiation dose assessment.

    PubMed

    Goldman, M

    1997-01-01

    Radiation dose reconstruction is used to estimate exposure to radiation that has occurred externally, e.g., from an atomic bomb, or internally, e.g., from radionuclide ingestion. This commentary reviews techniques for biological dosimetry that have been developed to estimate radiation doses from internal exposures, but which can also be used to estimate external exposures. The author argues for increased development and use of these biological tools.

  14. AGING FACILITY WORKER DOSE ASSESSMENT

    SciTech Connect

    R.L. Thacker

    2005-03-24

    The purpose of this calculation is to estimate radiation doses received by personnel working in the Aging Facility performing operations to transfer aging casks to the aging pads for thermal and logistical management, stage empty aging casks, and retrieve aging casks from the aging pads for further processing in other site facilities. Doses received by workers due to aging cask surveillance and maintenance operations are also included. The specific scope of work contained in this calculation covers both collective doses and individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation from normal operation. There are no Category 1 event sequences associated with the Aging Facility (BSC 2004 [DIRS 167268], Section 7.2.1). The results of this calculation will be used to support the design of the Aging Facility and to provide occupational dose estimates for the License Application. The calculations contained in this document were developed by Environmental and Nuclear Engineering of the Design and Engineering Organization and are intended solely for the use of the Design and Engineering Organization in its work regarding facility operation. Yucca Mountain Project personnel from the Environmental and Nuclear Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than authorized personnel in Environmental and Nuclear Engineering.

  15. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: focus on the cancer hallmark of tumor angiogenesis

    PubMed Central

    Hu, Zhiwei; Brooks, Samira A.; Dormoy, Valérian; Hsu, Chia-Wen; Hsu, Hsue-Yin; Lin, Liang-Tzung; Massfelder, Thierry; Rathmell, W. Kimryn; Xia, Menghang; Al-Mulla, Fahd; Al-Temaimi, Rabeah; Amedei, Amedeo; Brown, Dustin G.; Prudhomme, Kalan R.; Colacci, Annamaria; Hamid, Roslida A.; Mondello, Chiara; Raju, Jayadev; Ryan, Elizabeth P.; Woodrick, Jordan; Scovassi, A. Ivana; Singh, Neetu; Vaccari, Monica; Roy, Rabindra; Forte, Stefano; Memeo, Lorenzo; Salem, Hosni K.; Lowe, Leroy; Jensen, Lasse; Bisson, William H.; Kleinstreuer, Nicole

    2015-01-01

    One of the important ‘hallmarks’ of cancer is angiogenesis, which is the process of formation of new blood vessels that are necessary for tumor expansion, invasion and metastasis. Under normal physiological conditions, angiogenesis is well balanced and controlled by endogenous proangiogenic factors and antiangiogenic factors. However, factors produced by cancer cells, cancer stem cells and other cell types in the tumor stroma can disrupt the balance so that the tumor microenvironment favors tumor angiogenesis. These factors include vascular endothelial growth factor, endothelial tissue factor and other membrane bound receptors that mediate multiple intracellular signaling pathways that contribute to tumor angiogenesis. Though environmental exposures to certain chemicals have been found to initiate and promote tumor development, the role of these exposures (particularly to low doses of multiple substances), is largely unknown in relation to tumor angiogenesis. This review summarizes the evidence of the role of environmental chemical bioactivity and exposure in tumor angiogenesis and carcinogenesis. We identify a number of ubiquitous (prototypical) chemicals with disruptive potential that may warrant further investigation given their selectivity for high-throughput screening assay targets associated with proangiogenic pathways. We also consider the cross-hallmark relationships of a number of important angiogenic pathway targets with other cancer hallmarks and we make recommendations for future research. Understanding of the role of low-dose exposure of chemicals with disruptive potential could help us refine our approach to cancer risk assessment, and may ultimately aid in preventing cancer by reducing or eliminating exposures to synergistic mixtures of chemicals with carcinogenic potential. PMID:26106137

  16. Radiation environments and absorbed dose estimations on manned space missions.

    PubMed

    Curtis, S B; Atwell, W; Beever, R; Hardy, A

    1986-01-01

    In order to make an assessment of radiation risk during manned missions in space, it is necessary first to have as accurate an estimation as possible of the radiation environment within the spacecraft to which the astronauts will be exposed. Then, with this knowledge and the inclusion of body self-shielding, estimations can be made of absorbed doses for various body organs (skin, eye, blood-forming organs, etc.). A review is presented of our present knowledge of the radiation environments and absorbed doses expected for several space mission scenarios selected for our development of the new radiation protection guidelines. The scenarios selected are a 90-day mission at an altitude (450 km) and orbital inclinations (28.5 degrees, 57 degrees and 90 degrees) appropriate for NASA's Space Station, a 15-day sortie to geosynchronous orbit and a 90-day lunar mission. All scenarios chosen yielded dose equivalents between five and ten rem to the blood forming organs if no large solar particle event were encountered. Such particle events could add considerable exposure particularly to the skin and eye for all scenarios except the one at 28.5 degrees orbital inclination.

  17. Dose rate assessment in tooth enamel

    NASA Astrophysics Data System (ADS)

    Wieser, A.; Göksu, H. Y.; Regulla, D. F.; Vogenauer, A.

    A mammoth found in the southern part of Germany was dated by ESR spectroscopy. This dating method is based on the measurement of the accumulated dose in tooth enamel and assessment of the annual dose. The accumulated dose is obtained from the radiation induced ESR signal at g = 2.0018 of the enamel. The annual dose was first determined by measuring the 238U, 232Th and 40K content of the tooth and of the surrounding soil. As a crosscheck, the dose rate from the tooth was measured by inserting TL dosimeters in the dentine and storing them at 'zero' background in a salt mine. The cosmic dose rate and the gamma dose rate from the soil was evaluated from TL dosimeters buried at the excavation site. The results are discussed with respect to the applicability of ESR dating on teeth.

  18. Biodosimetry and assessment of radiation dose

    PubMed Central

    Crespo, Rafael Herranz; Domene, Mercedes Moreno; Rodríguez, María Jesús Prieto

    2011-01-01

    Aim When investigating radiation accidents, it is very important to determine the exposition dose to the individuals. In the case of exposures over 1 Gy, clinicians may expect deterministic effects arising the following weeks and months, in these cases dose estimation will help physicians in the planning of therapy. Nevertheless, for doses below 1 Gy, biodosimetry data are important due to the risk of developing late stochastic effects. Finally, some accidental overexposures are lack of physical measurements and the only way of quantifying dose is by biological dosimetry. Background The analysis of chromosomal aberrations by different techniques is the most developed method of quantifying dose to individuals exposed to ionising radiations.1,2 Furthermore, the analysis of dicentric chromosomes observed in metaphases from peripheral lymphocytes is the routine technique used in case of acute exposures to assess radiation doses. Materials and methods Solid stain of chromosomes is used to determine dicentric yields for dose estimation. Fluorescence in situ hybridization (FISH) for translocations analysis is used when delayed sampling or suspected chronically irradiation dose assessment. Recommendations in technical considerations are based mainly in the IAEA Technical Report No. 405.2 Results Experience in biological dosimetry at Gregorio Marañón General Hospital is described, including own calibration curves used for dose estimation, background studies and real cases of overexposition. Conclusion Dose assessment by biological dosimeters requires a large previous standardization work and a continuous update. Individual dose assessment involves high qualification professionals and its long time consuming, therefore requires specific Centres. For large mass casualties cooperation among specialized Institutions is needed. PMID:24376970

  19. An updated dose assessment for Rongelap Island

    SciTech Connect

    Robison, W.L.; Conrado, C.L.; Bogen, K.T.

    1994-07-01

    We have updated the radiological dose assessment for Rongelap Island at Rongelap Atoll using data generated from field trips to the atoll during 1986 through 1993. The data base used for this dose assessment is ten fold greater than that available for the 1982 assessment. Details of each data base are presented along with details about the methods used to calculate the dose from each exposure pathway. The doses are calculated for a resettlement date of January 1, 1995. The maximum annual effective dose is 0.26 mSv y{sup {minus}1} (26 mrem y{sup {minus}1}). The estimated 30-, 50-, and 70-y integral effective doses are 0.0059 Sv (0.59 rem), 0.0082 Sv (0.82 rem), and 0.0097 Sv (0.97 rem), respectively. More than 95% of these estimated doses are due to 137-Cesium ({sup 137}Cs). About 1.5% of the estimated dose is contributed by 90-Strontium ({sup 90}Sr), and about the same amount each by 239+240-Plutonium ({sup 239+240}PU), and 241-Americium ({sup 241}Am).

  20. Optical fibres for high radiation dose environments

    NASA Astrophysics Data System (ADS)

    Henschel, H.; Kohn, O.; Schmidt, H. U.; Bawirzanski, E.; Landers, A.

    1994-06-01

    A variety of modern single mode (SM) and graded index (GI) fibres as well as a new pure silica multimode step index (MMSI) fibre with high OH content were irradiated at a Co-60 gamma ray source with a dose rate of approximately = 1.5Gy/s up to a total dose of 10(exp 6)Gy. The radiation-induced loss of all fibres was measured continuously during and after irradiation at discrete wavelengths (approximately = 850, approximately = 1070, approximately = 1300, approximately = 1550nm). With one SM fibre type also the 'breaking stress' before and after irradiation was determined. Radiation-induced losses of approximately less than 5dB/50m (at approximately = 1300nm) were found with some of the SM fibres, whereas the MMSI fibre showed a final induced loss of only 0.5dB/50m at 1070nm wavelength. The breaking stress of the SM fibre increased by about 10%.

  1. Assessing dose rate distributions in VMAT plans

    NASA Astrophysics Data System (ADS)

    Mackeprang, P.-H.; Volken, W.; Terribilini, D.; Frauchiger, D.; Zaugg, K.; Aebersold, D. M.; Fix, M. K.; Manser, P.

    2016-04-01

    Dose rate is an essential factor in radiobiology. As modern radiotherapy delivery techniques such as volumetric modulated arc therapy (VMAT) introduce dynamic modulation of the dose rate, it is important to assess the changes in dose rate. Both the rate of monitor units per minute (MU rate) and collimation are varied over the course of a fraction, leading to different dose rates in every voxel of the calculation volume at any point in time during dose delivery. Given the radiotherapy plan and machine specific limitations, a VMAT treatment plan can be split into arc sectors between Digital Imaging and Communications in Medicine control points (CPs) of constant and known MU rate. By calculating dose distributions in each of these arc sectors independently and multiplying them with the MU rate, the dose rate in every single voxel at every time point during the fraction can be calculated. Independently calculated and then summed dose distributions per arc sector were compared to the whole arc dose calculation for validation. Dose measurements and video analysis were performed to validate the calculated datasets. A clinical head and neck, cranial and liver case were analyzed using the tool developed. Measurement validation of synthetic test cases showed linac agreement to precalculated arc sector times within  ±0.4 s and doses  ±0.1 MU (one standard deviation). Two methods for the visualization of dose rate datasets were developed: the first method plots a two-dimensional (2D) histogram of the number of voxels receiving a given dose rate over the course of the arc treatment delivery. In similarity to treatment planning system display of dose, the second method displays the dose rate as color wash on top of the corresponding computed tomography image, allowing the user to scroll through the variation over time. Examining clinical cases showed dose rates spread over a continuous spectrum, with mean dose rates hardly exceeding 100 cGy min-1 for conventional

  2. ASSESSING POPULATION EXPOSURES TO MULTIPLE AIR POLLUTANTS USING A MECHANISTIC SOURCE-TO-DOSE MODELING FRAMEWORK

    EPA Science Inventory

    The Modeling Environment for Total Risks studies (MENTOR) system, combined with an extension of the SHEDS (Stochastic Human Exposure and Dose Simulation) methodology, provide a mechanistically consistent framework for conducting source-to-dose exposure assessments of multiple pol...

  3. ASSESSING POPULATION EXPOSURES TO MULTIPLE AIR POLLUTANTS USING A MECHANISTIC SOURCE-TO-DOSE MODELING FRAMEWORK

    EPA Science Inventory

    The Modeling Environment for Total Risks studies (MENTOR) system, combined with an extension of the SHEDS (Stochastic Human Exposure and Dose Simulation) methodology, provide a mechanistically consistent framework for conducting source-to-dose exposure assessments of multiple pol...

  4. The SIETTE Automatic Assessment Environment

    ERIC Educational Resources Information Center

    Conejo, Ricardo; Guzmán, Eduardo; Trella, Monica

    2016-01-01

    This article describes the evolution and current state of the domain-independent Siette assessment environment. Siette supports different assessment methods--including classical test theory, item response theory, and computer adaptive testing--and integrates them with multidimensional student models used by intelligent educational systems.…

  5. The SIETTE Automatic Assessment Environment

    ERIC Educational Resources Information Center

    Conejo, Ricardo; Guzmán, Eduardo; Trella, Monica

    2016-01-01

    This article describes the evolution and current state of the domain-independent Siette assessment environment. Siette supports different assessment methods--including classical test theory, item response theory, and computer adaptive testing--and integrates them with multidimensional student models used by intelligent educational systems.…

  6. Assessing the Academic Networked Environment.

    ERIC Educational Resources Information Center

    Lippincott, Joan K.

    1999-01-01

    Describes a project of the Coalition for Networked Information, founded in 1990 to advance scholarship interest in the networked-computer environment. The project coordinated work of seven higher education institutions in conducting assessments of their campus networks. Topics discussed include the networking climate on campuses, why assessment is…

  7. Simulation Assessment Validation Environment (SAVE)

    DTIC Science & Technology

    2000-09-01

    AFRL-ML-WP-TR-2001-4088 SIMULATION ASSESSMENT VALIDATION ENVIRONMENT (SAVE) Paul Cole Bob Bassett Marcia Herndon Paul Collins Kathy Jacobson James...DD-MM-YYYY) 01-09-2000 2. REPORT TYPE Final 3. DATES COVERED (FROM - TO) 01-04-1995 to 30-09-2000 4. TITLE AND SUBTITLE Simulation Assessment ...SUBTITLE Simulation Assessment Validation Environment (SAVE) 5. FUNDING NUMBERS C F33615-95-C-5538 PE 63800F PR 2025 TA 50 6. AUTHOR(S) Paul

  8. Quality assessment of urban environment

    NASA Astrophysics Data System (ADS)

    Ovsiannikova, T. Y.; Nikolaenko, M. N.

    2015-01-01

    This paper is dedicated to the research applicability of quality management problems of construction products. It is offered to expand quality management borders in construction, transferring its principles to urban systems as economic systems of higher level, which qualitative characteristics are substantially defined by quality of construction product. Buildings and structures form spatial-material basis of cities and the most important component of life sphere - urban environment. Authors justify the need for the assessment of urban environment quality as an important factor of social welfare and life quality in urban areas. The authors suggest definition of a term "urban environment". The methodology of quality assessment of urban environment is based on integrated approach which includes the system analysis of all factors and application of both quantitative methods of assessment (calculation of particular and integrated indicators) and qualitative methods (expert estimates and surveys). The authors propose the system of indicators, characterizing quality of the urban environment. This indicators fall into four classes. The authors show the methodology of their definition. The paper presents results of quality assessment of urban environment for several Siberian regions and comparative analysis of these results.

  9. Ivermectin dose assessment without weighing scales.

    PubMed Central

    Alexander, N. D.; Cousens, S. N.; Yahaya, H.; Abiose, A.; Jones, B. R.

    1993-01-01

    Described are two alternatives to the weighing of patients for assessing the dose of ivermectin for use in mass chemotherapy campaigns against onchocerciasis. The first method uses height to separate patients into four dosing categories (1/2, 1, 11/2 and 2 tablets), while the second involves estimating one of these dosing categories according to an individual's physical appearance, without making any measurements. Data for the height-based method were obtained from 6373 people who were taking part in a placebo-controlled trial of ivermectin in northern Nigeria. Use of an arbitrary trade-off of approximately 100 people "overdosed" for every person "underdosed" would lead to 0.5% of the population being underdosed by 1/2 tablet, 46.5% being dosed correctly, 51.7% being overdosed by 1/2 tablet, and 1.2% being overdosed by 1 tablet. The physical appearance approach involved three observers and 779 subjects. A total of 82% of the observers' estimates were "correct", with all the incorrect dosing deviating by only 1/2 tablet from the dose that the subjects should have received. PMID:8324855

  10. Computed Tomography: Image and Dose Assessment

    SciTech Connect

    Valencia-Ortega, F.; Ruiz-Trejo, C.; Rodriguez-Villafuerte, M.; Buenfil, A. E.; Mora-Hernandez, L. A.

    2006-09-08

    In this work an experimental evaluation of image quality and dose imparted during a computed tomography study in a Public Hospital in Mexico City is presented; The measurements required the design and construction of two phantoms at the Institute of Physics, UNAM, according to the recommendations of American Association of Physicists in Medicine (AAPM). Image assessment was performed in terms the spatial resolution and image contrast. Dose measurements were carried out using LiF: Mg,Ti (TLD-100) dosemeters and pencil-shaped ionisation chamber; The results for a computed tomography head study in single and multiple detector modes are presented.

  11. Spectroscopic gamma camera for use in high dose environments

    NASA Astrophysics Data System (ADS)

    Ueno, Yuichiro; Takahashi, Isao; Ishitsu, Takafumi; Tadokoro, Takahiro; Okada, Koichi; Nagumo, Yasushi; Fujishima, Yasutake; Kometani, Yutaka; Suzuki, Yasuhiko; Umegaki, Kikuo

    2016-06-01

    We developed a pinhole gamma camera to measure distributions of radioactive material contaminants and to identify radionuclides in extraordinarily high dose regions (1000 mSv/h). The developed gamma camera is characterized by: (1) tolerance for high dose rate environments; (2) high spatial and spectral resolution for identifying unknown contaminating sources; and (3) good usability for being carried on a robot and remotely controlled. These are achieved by using a compact pixelated detector module with CdTe semiconductors, efficient shielding, and a fine resolution pinhole collimator. The gamma camera weighs less than 100 kg, and its field of view is an 8 m square in the case of a distance of 10 m and its image is divided into 256 (16×16) pixels. From the laboratory test, we found the energy resolution at the 662 keV photopeak was 2.3% FWHM, which is enough to identify the radionuclides. We found that the count rate per background dose rate was 220 cps h/mSv and the maximum count rate was 300 kcps, so the maximum dose rate of the environment where the gamma camera can be operated was calculated as 1400 mSv/h. We investigated the reactor building of Unit 1 at the Fukushima Dai-ichi Nuclear Power Plant using the gamma camera and could identify the unknown contaminating source in the dose rate environment that was as high as 659 mSv/h.

  12. Neuropsychological Assessment in Extreme Environments

    DTIC Science & Technology

    2007-01-01

    Archives of Clinical Neuropsychology 22S (2007) S89–S99 Neuropsychological assessment in extreme environments Michael Lowe a,∗, Wayne Harris b...c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 S90 M. Lowe et al. / Archives of Clinical Neuropsychology 22S...et al. / Archives of Clinical Neuropsychology 22S (2007) S89–S99 S91 There was a 10% reduction in this score during the final hour of toluene

  13. VOXMAT: Hybrid Computational Phantom for Dose Assessment

    SciTech Connect

    Akkurt, Hatice; Eckerman, Keith F

    2007-01-01

    The Oak Ridge National Laboratory (ORNL) computational phantoms have been the standard for assessing the radiation dose due to internal and external exposure over the past three decades. In these phantoms, the body surface and each organ are approximated by mathematical equations; hence, some of the organs are not necessarily realistic in their shape. Over the past two decades, these phantoms have been revised and updated: some of the missing internal organs have been added and the locations of the existing organs have been revised (e.g., thyroid). In the original phantom, only three elemental compositions were used to describe all body tissues. Recently, the compositions of the organs have been updated based on ICRP-89 standards. During the past decade, phantoms based on CT scans were developed for use in dose assessment. Although their shapes are realistic, some computational challenges are noted; including increased computational times and increased memory requirements. For good spatial resolution, more than several million voxels are used to represent the human body. Moreover, when CT scans are obtained, the subject is in a supine position with arms at the side. In some occupational exposure cases, it is necessary to evaluate the dose with the arms and legs in different positions. It will be very difficult and inefficient to reposition the voxels defining the arms and legs to simulate these exposure geometries. In this paper, a new approach for computational phantom development is presented. This approach utilizes the combination of a mathematical phantom and a voxelized phantom for the representation of the anatomy.

  14. Cancer Dose-Response Assessment for Polychlorinated Biphenyls (PCBs) and Application to Environmental Mixtures

    EPA Pesticide Factsheets

    This report updates the cancer dose-response assessment for PCBs and shows how information on toxicity, disposition, and environmental processes can be considered together to evaluate health risks from PCB mixtures in the environment.

  15. Assessment of Noble Gases in the Savannah River Site Environment

    SciTech Connect

    Carlton, W.H.; Murphy, C.E. Jr.

    1995-04-01

    A series of documents has been published that assesses the impact of various radionuclides released to the environment by Savannah River Site operations. The quantity released, the disposition of the radionuclides in the environment, and the dose to offsite individuals has been presented for carbon, cesium, iodine, plutonium, strontium, technetium, tritium, and uranium. An assessment of the impact of non-radioactive mercury also has been published.

  16. Preliminary dose assessment of the Chernobyl accident

    SciTech Connect

    Hull, A.P.

    1987-01-01

    From the major accident at Unit 4 of the Chernobyl nuclear power station, a plume of airborne radioactive fission products was initially carried northwesterly toward Poland, thence toward Scandinavia and into Central Europe. Reports of the levels of radioactivity in a variety of media and of external radiation levels were collected in the Department of Energy's Emergency Operations Center and compiled into a data bank. Portions of these and other data which were obtained directly from published and official reports were utilized to make a preliminary assessment of the extent and magnitude of the external dose to individuals downwind from Chernobyl. Radioactive /sup 131/I was the predominant fission product. The time of arrival of the plume and the maximum concentrations of /sup 131/I in air, vegetation and milk and the maximum reported depositions and external radiation levels have been tabulated country by country. A large amount of the total activity in the release was apparently carried to a significant elevation. The data suggest that in areas where rainfall occurred, deposition levels were from ten to one-hundred times those observed in nearby ''dry'' locations. Sufficient spectral data were obtained to establish average release fractions and to establish a reference spectra of the other nuclides in the release. Preliminary calculations indicated that the collective dose equivalent to the population in Scandinavia and Central Europe during the first year after the Chernobyl accident would be about 8 x 10/sup 6/ person-rem. From the Soviet report, it appears that a first year population dose of about 2 x 10/sup 7/ person-rem (2 x 10/sup 5/ Sv) will be received by the population who were downwind of Chernobyl within the U.S.S.R. during the accident and its subsequent releases over the following week. 32 refs., 14 figs., 20 tabs.

  17. Radiation environments and absorbed dose estimations on manned space missions

    NASA Technical Reports Server (NTRS)

    Curtis, S. B.; Atwell, W.; Beever, R.; Hardy, A.

    1986-01-01

    The dose and dose-equivalent estimates that astronauts might be expected to receive in space were assessed for the development of new radiation protection guidelines, considering several space mission scenarios. These scenarios included a 90-day LEO mission at 450 km altitude with orbital inclinations appropriate for NASA's Space Station (28.5, 57, and 90 deg), a 15-day sortie to GEO, and a 90-day lunar mission. All the missions contemplated would present space travelers with dose equivalents between 5 and 10 rem to the blood-forming organs, assuming no encounter with a large solar particle event; a large particle event could add considerable exposure for all scenarios except for the one at 28.5 orbital inclination. Adequate shielding must be included to guard against the radiation produced by such events.

  18. Interactive Rapid Dose Assessment Model (IRDAM): scenarios for comparing dose-assessment models. Vol. 3

    SciTech Connect

    Poeton, R.W.; Moeller, M.P.; Laughlin, G.J.; Desrosiers, A.E.

    1983-05-01

    The Interactive Rapid Dose Assessment Model (IRDAM) is a micro-computer based program designed to provide rapid assessments of the radiological impact of accidents at nuclear power plants. The main body of this document consists of 28 examples of IRDAM input and output, representing various types of accidents and releases. These examples are intended to provide a basis for comparison with other models or for testing IRDAM itself. Figures are included which show dose rates calculated by IRDAM for each scenario. Figures are also included which show calculations made using the computer codes WRAITH (Scherpelz, Borst and Hoenes, 1980) and RADPUR (Dabbert, et. al., 1982). Two other companion volumes to this one provide additional information on IRDAM. The User's Guide (NUREG/CR-3012, Volume 1) describes the setup and operation of equipment necessary to run IRDAM. Reactor Accident Assessment Methods (NUREG/CR-3012, Volume 2) describes the technical bases for IRDAM including methods, models and assumptions used in calculations.

  19. Pedestrians in Traffic Environments: Ultrafine Particle Respiratory Doses

    PubMed Central

    Manigrasso, Maurizio; Natale, Claudio; Vitali, Matteo; Protano, Carmela; Avino, Pasquale

    2017-01-01

    Particulate matter has recently received more attention than other pollutants. PM10 and PM2.5 have been primarily monitored, whereas scientists are focusing their studies on finer granulometric sizes due both to their high number concentration and their high penetration efficiency into the respiratory system. The purpose of this study is to investigate the population exposure to UltraFine Particles (UFP, submicrons in general) in outdoor environments. The particle number doses deposited into the respiratory system have been compared between healthy individuals and persons affected by Chronic Obstructive Pulmonary Disease (COPD). Measurements were performed by means of Dust Track and Nanoscan analyzers. Forty minute walking trails through areas with different traffic densities in downtown Rome have been considered. Furthermore, particle respiratory doses have been estimated for persons waiting at a bus stop, near a traffic light, or along a high-traffic road, as currently occurs in a big city. Large differences have been observed between workdays and weekdays: on workdays, UFP number concentrations are much higher due to the strong contribution of vehicular exhausts. COPD-affected individuals receive greater doses than healthy individuals due to their higher respiratory rate. PMID:28282961

  20. Background radiation dose of dumpsites in Ota and Environs

    NASA Astrophysics Data System (ADS)

    Usikalu, M. R.; Ola, O. O.; Achuka, J. A.; Babarimisa, I. O.; Ayara, W. A.

    2017-05-01

    In-situ measurement of background radiation dose from selected dumpsites in Ota and its environs was done using Radialert Nuclear Radiation Monitor (Digilert 200). Ten measurements were taken from each dumpsite. The measured background radiation range between 0.015 mRhr-1 for AOD and 0.028 mRhr-1 for SUS dumpsites. The calculated annual equivalent doses vary between 1.31 mSvyr-1 for AOD and 2.28 mSv/yr for SUS dumpsites. The air absorbed dose calculated ranged from 150 nGyhr-1 to 280 nGy/hr for AOD and SUS dumpsites respectively with an average value of 217 nGyhr-1 for all the locations. All the estimated parameters were higher than permissible limit set for background radiation for the general public. Conclusively, the associated challenge and radiation burden posed by the wastes on the studied locations and scavengers is high. Therefore, there is need by the regulatory authorities to look into the way and how waste can be properly managed so as to alleviate the effects on the populace leaving and working in the dumpsites vicinity.

  1. Influence of radiocesium transfer and decontamination on ambient dose in Japanese forest environment

    NASA Astrophysics Data System (ADS)

    Kato, Hiroaki; Onda, Yuichi

    2016-04-01

    This study investigated the effect of post-depositional migration of radiocesium and decontamination on ambient dose rate in Japanese forest environment following the Fukushima Dai-ichi Nuclear Power Plant accident. We measured cesium-137 deposition from canopy to forest floor in association with rainfall and litterfall in two coniferous stands (plantation of Japanese cedar) and a deciduous broad-leaved forest stand (oak with red pine). We also measured temporal evolution of ambient dose rate at different height in each forest site. Radiocesium inventory balance in each forest component (e.g., canopy, litter and mineral soil layer) were established to determine causes of the measured changes of ambient dose rate in three forest sites. Furthermore, we assessed influence of forest decontamination (removal of organic layer of forest floor) on spatial pattern of radiocesium at the forest floor and reduction of ambient dose rate.

  2. CANISTER HANDLING FACILITY WORKER DOSE ASSESSMENT

    SciTech Connect

    D.T. Dexheimer

    2004-02-27

    The purpose of this calculation is to estimate radiation doses received by personnel working in the Canister Handling Facility (CHF) performing operations to receive transportation casks, transfer wastes, prepare waste packages, perform associated equipment maintenance. The specific scope of work contained in this calculation covers individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation. The results of this calculation will be used to support the design of the CHF and provide occupational dose estimates for the License Application.

  3. DRY TRANSFER FACILITY WORKER DOSE ASSESSMENT

    SciTech Connect

    J.S. Tang

    2004-09-23

    The purpose of this calculation is to estimate radiation doses received by personnel working in the Dry Transfer Facility No.1 (DTF-1) performing operations to receive transportation casks, transfer wastes, prepare waste packages, and ship out loaded waste packages and empty casks. Doses received by workers due to maintenance operations are also included in this revision. The specific scope of work contained in this calculation covers both collective doses and individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation from normal operation, excluding the remediation area of the building. The results of this calculation will be used to support the design of the DTF-1 and to provide occupational dose estimates for the License Application. The calculations contained in this document were developed by Environmental and Nuclear Engineering of the Design and Engineering Organization and are intended solely for the use of the Design and Engineering Organization in its work regarding facility operation. Yucca Mountain Project personnel from the Environmental and Nuclear Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than authorized personnel in the Environmental and Nuclear Engineering.

  4. MESORAD dose assessment of the Chernobyl reactor accident

    SciTech Connect

    Ramsdell, J.V.; Hubbe, J.M.; Athey, G.F.; Davis, W.E.

    1989-12-01

    An accident involving Unit 4 of the Chernobylskaya Atomic Energy Station resulted in the release of a large amount of radioactive material to the atmosphere. This report describes the results of an assessment of the doses near the site (within 80 km) made at the Pacific Northwest Laboratory using the MESORAD Dose Assessment model. 6 refs., 10 figs., 5 tabs.

  5. Personnel Dose Assessment during Active Interrogation

    SciTech Connect

    Miller, Thomas Martin; Akkurt, Hatice; Patton, Bruce W

    2010-01-01

    A leading candidate in the detection of special nuclear material (SNM) is active interrogation (AI). Unlike passive interrogation, AI uses a source to enhance or create a detectable signal from SNM (usually fission), particularly in shielded scenarios or scenarios where the SNM has a low activity. The use of AI thus makes the detection of SNM easier or, in some scenarios, even enables previously impossible detection. During the development of AI sources, significant effort is put into determining the source strength required to detect SNM in specific scenarios. Usually during this process, but not always, an evaluation of personnel dose is also completed. In this instance personnel dose could involve any of the following: (1) personnel performing the AI; (2) unknown stowaways who are inside the object being interrogated; or (3) in clandestine interrogations, personnel who are known to be inside the object being interrogated but are unaware of the interrogation. In most instances, dose to anyone found smuggling SNM will be a secondary issue. However, for the organizations performing the AI, legal if not moral considerations should make dose to the personnel performing the AI, unknown stowaways, or innocent bystanders in clandestine interrogations a serious concern.

  6. Preliminary pathway analysis for YMP preclosure biosphere dose assessment

    SciTech Connect

    Wu, D.; Liu, N.; Tappen, J.J.; Tung, C.H.

    1998-05-13

    The preliminary preclosure biosphere dose assessment for the Yucca Mountain Project (YMP) involves the calculation of a radiation dose to a subsistence farmer living near the proposed Yucca Mountain repository. Eight radionuclides, H-3, Co-60, Kr-85, Sr-90, Ru-106, I-129, Cs-134, and Cs-137, are considered in this study. Radiation doses resulting from unit release rates of these radionuclides are analyzed. Total dose has been broken down into components that result from various exposure pathways. By using this approach, the most important pathways that deliver a radiation dose to a subsistence farmer can be clearly identified.

  7. Iodine-129 Dose in LLW Disposal Facility Performance Assessments

    SciTech Connect

    Wilhite, E.L.

    1999-10-15

    Iodine-129 has the lowest Performance Assessment derived inventory limit in SRS disposal facilities. Because iodine is concentrated in the body to one organ, the thyroid, it has been thought that dilution with stable iodine would reduce the dose effects of 129I.Examination of the dose model used to establish the Dose conversion factor for 129I shows that, at the levels considered in performance assessments of low-level waste disposal facilities, the calculated 129I dose already accounts for ingestion of stable iodine. At higher than normal iodine ingestion rates, the uptake of iodine by the thyroid itself decrease, which effectively cancels out the isotopic dilution effect.

  8. Measurement and assessment of radiation dose of astronauts in space

    NASA Astrophysics Data System (ADS)

    Zhang, Binquan; Sun, Yue-qiang; Yang, Chuibai; Zhang, Shenyi; Liang, Jinbao

    Astronauts in flight are exposed by the space radiation, which is mainly composed of proton, electron, heavy ion, and neutron. To assess the radiation risk, measurement and assessment of radiation dose of astronauts is indispensable. Especially, measurement for heavy ion radiation is most important as it contributes the major dose. Until now, most of the measurements and assessments of radiation dose of astronauts are based on the LET (Linear Energy Transfer) spectrum of space radiation. However, according to the ICRP Publication 123, energy and charge number of heavy ions should be measured in order to assess space radiation exposure to astronauts. In addition, from the publication, quality factors for each organs or tissues of astronauts are different and they should be calculated or measured independently. Here, a method to measure the energy and charge number of heavy ion and a voxel phantom based on the anatomy of Chinese adult male are presented for radiation dose assessment of astronauts.

  9. Assessment of the dose from radon and its decay products in the Bozkov dolomite cave.

    PubMed

    Rovenská, K; Thinová, L; Zdímal, V

    2008-01-01

    The dose from radon and its progeny remains a frequently discussed problem. ICRP 65 provides a commonly used methodology to calculate the dose from radon. Our work focuses on a cave environment and on assessing the doses in public open caves. The differences in conditions (aerosol size distribution, humidity, radon and its progeny ratio, etc.) are described by the so-called cave factor j. The cave factor is used to correct the dose for workers which is calculated using the ICRP 65 recommendation. In this work, the authors have brought together measured data of aerosol size distribution, unattached and attached fraction activity, and have calculated the so-called cave factor for the Bozkov dolomite cave environment. The dose conversion factors based on measured data and used for evaluating the cave factor were calculated by LUDEP software, which implements HRTM ICRP66.

  10. Assessing and Developing Administrators for Turbulent Environments

    ERIC Educational Resources Information Center

    Hunsaker, Phillip; And Others

    1975-01-01

    Notes the turbulence of the environments in which administrators must operate, presents an assessment model for identifying and developing administrators with the necessary capabilities for coping effectively with turbulent field environments, and suggests applications for and further investigations of the model. (Author/IRT)

  11. DOSE ASSESSMENTS FROM THE DISPOSAL OF LOW ...

    EPA Pesticide Factsheets

    Modeling the long-term performance of the RCRA-C disposal cell and potential doses to off-site receptors is used to derive maximum radionuclide specific concentrations in the wastes that would enable these wastes to be disposed of safely using the RCRA-C disposal cell technology. Modeling potential exposures to derive these waste acceptance concentrations involves modeling exposures to workers during storage, treatment and disposal of the wastes, as well as exposures to individuals after disposal operations have ceased. Post facility closure exposures can result from the slow expected degradation of the disposal cell over long time periods (one thousand years after disposal) and in advertent human intrusion. Provide a means of determining waste acceptance radionuclide concentrations for disposal of debris from radiological dispersal device incidents as well as low-activity wastes generated in commercial, medical and research activities, potentially serve as the technical basis for guidance on disposal of these materials.

  12. A Framework for "Fit for Purpose" Dose Response Assessment

    EPA Science Inventory

    The NRC report Science and Decisions: Advancing Risk Assessment made several recommendations to improve chemical risk assessment, with a focus on in-depth chronic dose-response assessments conducted by the U.S. Environmental Protection Agency. The recommendations addressed two ...

  13. A Framework for "Fit for Purpose" Dose Response Assessment

    EPA Science Inventory

    The NRC report Science and Decisions: Advancing Risk Assessment made several recommendations to improve chemical risk assessment, with a focus on in-depth chronic dose-response assessments conducted by the U.S. Environmental Protection Agency. The recommendations addressed two ...

  14. Dose perturbations by electromagnetic transponders in the proton environment.

    PubMed

    Dolney, Derek; McDonough, James; Vapiwala, Neha; Metz, James M

    2013-03-07

    Surgically implanted electromagnetic transponders have been used in external beam radiotherapy for target localization and position monitoring in real time. The effect of transponders on proton therapy dose distributions has not been reported. A Monte Carlo implementation of the transponder geometry is validated against film measurements in a proton SOBP and subsequently used to generate dose distributions for transponders at different positions and orientations in the proton SOBP. The maximum dose deficit is extracted in each case. Dose shadows of up to 60% occur for transponders positioned very near the end of range of the Bragg peak. However, if transponders are positioned further than 5 mm from the end of range, and are not oriented parallel to the beam direction, then the dose deficit can be kept below 10%.

  15. Assessment of Student Attitudes Toward Learning Environments.

    ERIC Educational Resources Information Center

    Blair, Mark W.; Kershner, Keith M.

    The evaluators of the RBS (Research for Better Schools, Inc.) Career Education Program were confronted with the need for an instrument which would assess student attitudes toward learning environments which were not limited to traditional school settings. This study reviews the development of the Assessment of Student Attitudes Scale (ASA). The…

  16. Interactive Rapid Dose Assessment Model (IRDAM): user's guide

    SciTech Connect

    Poeton, R.W.; Moeller, M.P.; Laughlin, G.J.; Desrosiers, A.E.

    1983-05-01

    As part of the continuing emphasis on emergency preparedness the US Nuclear Regulatory Commission (NRC) sponsored the development of a rapid dose assessment system by Pacific Northwest Laboratory (PNL). This system, the Interactive Rapid Dose Assessment Model (IRDAM) is a micro-computer based program for rapidly assessing the radiological impact of accidents at nuclear power plants. This User's Guide provides instruction in the setup and operation of the equipment necessary to run IRDAM. Instructions are also given on how to load the magnetic disks and access the interactive part of the program. Two other companion volumes to this one provide additional information on IRDAM. Reactor Accident Assessment Methods (NUREG/CR-3012, Volume 2) describes the technical bases for IRDAM including methods, models and assumptions used in calculations. Scenarios for Comparing Dose Assessment Models (NUREG/CR-3012, Volume 3) provides the results of calculations made by IRDAM and other models for specific accident scenarios.

  17. Assessment of activation products in the Savannah River Site environment

    SciTech Connect

    Carlton, W.H.; Denham, M.

    1996-07-01

    This document assesses the impact of radioactive activation products released from SRS facilities since the first reactor became operational late in 1953. The isotopes reported here are those whose release resulted in the highest dose to people living near SRS: {sup 32}P, {sup 51}Cr, {sup 60}C, and {sup 65}Zn. Release pathways, emission control features, and annual releases to the aqueous and atmospheric environments are discussed. No single incident has resulted in a major acute release of activation products to the environment. The releases were the result of normal operations of the reactors and separations facilities. Releases declined over the years as better controls were established and production was reduced. The overall radiological impact of SRS activation product atmospheric releases from 1954 through 1994 on the offsite maximally exposed individual can be characterized by a total dose of 0.76 mrem. During the same period, such an individual received a total dose of 14,400 mrem from non-SRS sources of ionizing radiation present in the environment. SRS activation product aqueous releases between 1954 and 1994 resulted in a total dose of 54 mrem to the offsite maximally exposed individual. The impact of SRS activation product releases on offsite populations also has been evaluated.

  18. Environment, safety and health progress assessment manual

    SciTech Connect

    Not Available

    1992-12-01

    On June 27, 1989, the Secretary of Energy announced a 10-Point Initiative to strengthen environment, safety, and health (ES H) programs, and waste management activities at DOE production, research, and testing facilities. One of the points involved conducting dent Tiger Team Assessments of DOE operating facilities. The Office of Special independent Projects (OSP), EH-5, in the Office of the Assistant Secretary for Environment, Safety and Health, EH-1, was assigned the responsibility to conduct the Tiger Team Assessments. Through June 1992, a total of 35 Tiger Team Assessments were completed. The Secretary directed that Corrective Action Plans be developed and implemented to address the concerns identified by the Tiger Teams. In March 1991, the Secretary approved a plan for assessments that are more focused, concentrating on ES H management, ES H corrective actions, self-assessment programs, and root-cause related issues.'' In July 1991, the Secretary approved the initiation of ES H Progress Assessments, as a followup to the Tiger Team Assessments, and in the continuing effort to institutionalize the self-assessment process and line management accountability in the ES H areas. This manual documents the processes to be used to perform the ES H Progress Assessments. It was developed based upon the lessons learned from Tiger Team Assessments, the two pilot Progress Assessments, and Progress Assessments that have been completed. The manual will be updated periodically to reflect lessons learned or changes in policy.

  19. Environment, safety and health progress assessment manual

    SciTech Connect

    Not Available

    1992-12-01

    On June 27, 1989, the Secretary of Energy announced a 1O-Point Initiative to strengthen environment,safety, and health (ES H) programs, and waste management activities at involved conducting DOE production, research, and testing facilities. One of the points independent Tiger Team Assessments of DOE operating facilities. The Office of Special Projects (OSP), EH-5, in the Office of the Assistant Secretary for Environment, Safety and Health, EH-1, was assigned the responsibility to conduct the Tiger Team Assessments. Through June 1992, a total of 35 Tiger Team Assessments were completed. The Secretary directed that Corrective Action Plans be developed and implemented to address the concerns identified by the Tiger Teams. In March 1991, the Secretary approved a plan for assessments that are more focused, concentrating on ES H management, ES H corrective actions, self-assessment programs, and root-cause related issues.'' In July 1991, the Secretary approved the initiation of ES H Progress Assessments, as a followup to the Tiger Team Assessments, and in the continuing effort to institutionalize the self-assessment process and line management accountability in the ES H areas. This volume contains appendices to the Environment, Safety and Health Progress Assessment Manual.

  20. Automated size-specific CT dose monitoring program: Assessing variability in CT dose

    SciTech Connect

    Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan

    2012-11-15

    Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED{sub adj}). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED{sub adj} between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED{sub adj} that differed by up to 44% from effective dose estimates

  1. Assessment of tritium in the Savannah River Site environment

    SciTech Connect

    Carlton, W.H.; Murphy, C.E. Jr.; Bauer, L.R.

    1993-10-01

    This report is the first revision to a series of reports on radionuclides inn the SRS environment. Tritium was chosen as the first radionuclide in the series because the calculations used to assess the dose to the offsite population from SRS releases indicate that the dose due to tritium, through of small consequence, is one of the most important the radionuclides. This was recognized early in the site operation, and extensive measurements of tritium in the atmosphere, surface water, and ground water exist due to the effort of the Environmental Monitoring Section. In addition, research into the transport and fate of tritium in the environment has been supported at the SRS by both the local Department of Energy (DOE) Office and DOE`s Office of Health and Environmental Research.

  2. Environment Flow Assessment with Flow Regime Transition

    NASA Astrophysics Data System (ADS)

    Su, J.; Ho, C. C.; Chang, L. C.

    2015-12-01

    To avoid worsen river and estuarine ecosystems cause by overusing water resources, environmental flows conservation is applied to reduce the impact of river environment. Environmental flows refer to water provided within a river, wetland or coastal zone to sustain ecosystems and benefits to human wellbeing. Environment flow assessment is now widely accepted that a naturally variable flow regime, rather than just a minimum low flow. In this study, we propose four methods, experience method, Tenant method, hydraulic method and habitat method to assess the environmental flow of base flow, flush flow and overbank flow with different discharge, frequency and occurrence period. Dahan River has been chosen as a case to demonstrate the assessment mechanism. The alternatives impact analysis of environment and human water used provides a reference for stakeholders when holding an environmental flow consultative meeting.

  3. Mesorad dose assessment model. Volume 1. Technical basis

    SciTech Connect

    Scherpelz, R.I.; Bander, T.J.; Athey, G.F.; Ramsdell, J.V.

    1986-03-01

    MESORAD is a dose assessment model for emergency response applications. Using release data for as many as 50 radionuclides, the model calculates: (1) external doses resulting from exposure to radiation emitted by radionuclides contained in elevated or deposited material; (2) internal dose commitment resulting from inhalation; and (3) total whole-body doses. External doses from airborne material are calculated using semi-infinite and finite cloud approximations. At each stage in model execution, the appropriate approximation is selected after considering the cloud dimensions. Atmospheric processes are represented in MESORAD by a combination of Lagrangian puff and Gaussian plume dispersion models, a source depletion (deposition velocity) dry deposition model, and a wet deposition model using washout coefficients based on precipitation rates.

  4. Identification and dose assessment of irradiated cumin by EPR spectrometry.

    PubMed

    Abdel-Fattah, A A

    2002-03-01

    The use of electron paramagnetic resonance spectroscopy to accurately distinguish irradiated from unirradiated cumin and assess the absorbed dose to radiation-processed cumin is examined. The results were successful for identifying both irradiated and unirradiated cumin. Additive reirradiation of the cumin produces a reproducible dose response function, which can be used to assess the initial dose by back-extrapolation. Third-degree polynomial and exponential functions were used to fit the EPR signal/dose curves. It was found that the 3rd degree polynomial function provides satisfactory results without correction for decay of free radicals. The exponential fit to the data cannot be used without correction of decay of free radicals. The stability of the radiation-induced EPR signal of irradiated cumin was studied over a storage period of 6 months. The additive reirradiation of some samples was carried out at different storage times (10, 20 and 30 days) after initial irradiation.

  5. Radiological dose assessments of atolls in the Northern Marshall Islands

    SciTech Connect

    Robison, W.L.

    1983-11-01

    Methods and models used to estimate the radiation doses to a returning population of the atolls in the Marshall Islands are presented. In this environment natural processes have acted on source-term radionuclides for nearly 30 years. The data bases developed for the models, and the results of the radiological dose analyses at the various atolls are described. The major radionuclides in order of their contribution to the total estimated doses were /sup 137/Cs, /sup 90/Sr, /sup 239/ /sup 240/Pu, /sup 241/Am, and /sup 60/Co. Exposure pathways in order of their contribution to the estimated doses were: terrestrial food chain, external ..gamma.., marine food chain, inhalation, and cistern water and ground water. 56 references, 13 figures, 16 tables.

  6. The Northern Marshall Islands radiological survey: Data and dose assessments

    SciTech Connect

    Robison, W.L.; Noshkin, V.E.; Conrado, C.L.

    1997-07-01

    Fallout from atmospheric nuclear tests, especially from those conducted at the Pacific Proving Grounds between 1946 and 1958, contaminated areas of the Northern Marshall Islands. A radiological survey at some Northern Marshall Islands was conducted from September through November 1978 to evaluate the extent of residual radioactive contamination. The atolls included in the Northern Marshall Islands Radiological Survey (NMIRS) were Likiep, Ailuk, Utirik, Wotho, Ujelang, Taka, Rongelap, Rongerik, Bikar, Ailinginae, and Mejit and Jemo Islands. The original test sites, Bikini and Enewetak Atolls, were also visited on the survey. An aerial survey was conducted to determine the external gamma exposure rate. Terrestrial (soil, food crops, animals, and native vegetation), cistern and well water samples, and marine (sediment, seawater, fish and clams) samples were collected to evaluate radionuclide concentrations in the atoll environment. Samples were processed and analyzed for {sup 137}Cs, {sup 90}Sr, {sup 239+240}Pu and {sup 241}Am. The dose from the ingestion pathway was calculated using the radionuclide concentration data and a diet model for local food, marine, and water consumption. The ingestion pathway contributes 70% to 90% of the estimated dose. Approximately 95% of the dose is from {sup 137}Cs accounts for about 10% to 30% of the dose. {sup 239+240}Pu and {sup 241}Am are the major contributors to dose via the inhalation pathway; however, inhalation accounts for only about 1% of the total estimated dose, based on surface soil levels and resuspension studies. All doses are computed for concentrations decay corrected to 1996. The maximum annual effective dose from manmade radionuclides at these atolls ranges from .02 mSv y{sup -1}. The background dose in the Marshall Islands is estimated to be 2.4 mSv y{sup -1} to 4.5 mSv y{sup -1}. The 50-y integral dose ranges from 0.5 to 65 mSv. 35 refs., 2 figs., 9 tabs.

  7. PABLM: a computer program to calculate accumulated radiation doses from radionuclides in the environment

    SciTech Connect

    Napier, B.A.; Kennedy, W.E. Jr.; Soldat, J.K.

    1980-03-01

    A computer program, PABLM, was written to facilitate the calculation of internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. This report contains details of mathematical models used and calculational procedures required to run the computer program. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides in the environment after the releases have ended. Radioactive decay is considered during the release of radionuclides, after they are deposited on the plants or ground, and during holdup of food after harvest. The radiation dose models consider several exposure pathways. Doses may be calculated for either a maximum-exposed individual or for a population group. The doses calculated are accumulated doses from continuous chronic exposure. A first-year committed dose is calculated as well as an integrated dose for a selected number of years. The equations for calculating internal radiation doses are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and MPC's of each radionuclide. The radiation doses from external exposure to contaminated water and soil are calculated using the basic assumption that the contaminated medium is large enough to be considered an infinite volume or plane relative to the range of the emitted radiations. The equations for calculations of the radiation dose from external exposure to shoreline sediments include a correction for the finite width of the contaminated beach.

  8. External dose assessment in the Ukraine following the Chernobyl accident

    NASA Astrophysics Data System (ADS)

    Frazier, Remi Jordan Lesartre

    While the physiological effects of radiation exposure have been well characterized in general, it remains unclear what the relationship is between large-scale radiological events and psychosocial behavior outcomes in individuals or populations. To investigate this, the National Science Foundation funded a research project in 2008 at the University of Colorado in collaboration with Colorado State University to expand the knowledge of complex interactions between radiation exposure, perception of risk, and psychosocial behavior outcomes by modeling outcomes for a representative sample of the population of the Ukraine which had been exposed to radiocontaminant materials released by the reactor accident at Chernobyl on 26 April 1986. In service of this project, a methodology (based substantially on previously published models specific to the Chernobyl disaster and the Ukrainian population) was developed for daily cumulative effective external dose and dose rate assessment for individuals in the Ukraine for as a result of the Chernobyl disaster. A software platform was designed and produced to estimate effective external dose and dose rate for individuals based on their age, occupation, and location of residence on each day between 26 April 1986 and 31 December 2009. A methodology was developed to transform published 137Cs soil deposition contour maps from the Comprehensive Atlas of Caesium Deposition on Europe after the Chernobyl Accident into a geospatial database to access these data as a radiological source term. Cumulative effective external dose and dose rate were computed for each individual in a 703-member cohort of Ukrainians randomly selected to be representative of the population of the country as a whole. Error was estimated for the resulting individual dose and dose rate values with Monte Carlo simulations. Distributions of input parameters for the dose assessment methodology were compared to computed dose and dose rate estimates to determine which

  9. Assessment of the effective dose equivalent for external photon radiation

    SciTech Connect

    Reece, W.D.; Poston, J.W.; Xu, X.G. )

    1993-02-01

    Beginning in January 1994, US nuclear power plants must change the way that they determine the radiation exposure to their workforce. At that time, revisions to Title 10 Part 20 of the Code of Federal Regulations will be in force requiring licensees to evaluate worker radiation exposure using a risk-based methodology termed the effective dose equivalent.'' A research project was undertaken to improve upon the conservative method presently used for assessing effective dose equivalent. In this project effective dose equivalent was calculated using a mathematical model of the human body, and tracking photon interactions for a wide variety of radiation source geometries using Monte Carlo computer code simulations. Algorithms were then developed to relate measurements of the photon flux on the surface of the body (as measured by dosimeters) to effective dose equivalent. This report (Volume I of a two-part study) describes: the concept of effective dose equivalent, the evolution of the concept and its incorporation into regulations, the variations in human organ susceptibility to radiation, the mathematical modeling and calculational techniques used, the results of effective dose equivalent calculations for a broad range of photon energiesand radiation source geometries. The study determined that for beam radiation sources the highest effective dose equivalent occurs for beams striking the front of the torso. Beams striking the rear of the torsoproduce the next highest effective dose equivalent, with effective dose equivalent falling significantly as one departs from these two orientations. For point sources, the highest effective dose equivalent occurs when the sources are in contact with the body on the front of the torso. For females the highest effective dose equivalent occurs when the source is on the sternum, for males when it is on the gonads.

  10. EYE LENS EXPOSURE TO MEDICAL STAFF PERFORMING ELECTROPHYSIOLOGY PROCEDURES: DOSE ASSESSMENT AND CORRELATION TO PATIENT DOSE.

    PubMed

    Ciraj-Bjelac, Olivera; Antic, Vojislav; Selakovic, Jovana; Bozovic, Predrag; Arandjic, Danijela; Pavlovic, Sinisa

    2016-12-01

    The purpose of this study was to assess the patient exposure and staff eye dose levels during implantation procedures for all types of pacemaker therapy devices performed under fluoroscopic guidance and to investigate potential correlation between patients and staff dose levels. The mean eye dose during pacemaker/defibrillator implementation was 12 µSv for the first operator, 8.7 µSv for the second operator/nurse and 0.50 µSv for radiographer. Corresponding values for cardiac resynchronisation therapy procedures were 30, 26 and 2.0 µSv, respectively. Significant (p < 0.01) correlation between the eye dose and the kerma-area product was found for the first operator and radiographers, but not for other staff categories. The study revealed eye dose per procedure and eye dose normalised to patient dose indices for different staff categories and provided an input for radiation protection in electrophysiology procedures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Peak Dose Assessment for Proposed DOE-PPPO Authorized Limits

    SciTech Connect

    Maldonado, Delis

    2012-06-01

    The Oak Ridge Institute for Science and Education (ORISE), a U.S. Department of Energy (DOE) prime contractor, was contracted by the DOE Portsmouth/Paducah Project Office (DOE-PPPO) to conduct a peak dose assessment in support of the Authorized Limits Request for Solid Waste Disposal at Landfill C-746-U at the Paducah Gaseous Diffusion Plant (DOE-PPPO 2011a). The peak doses were calculated based on the DOE-PPPO Proposed Single Radionuclides Soil Guidelines and the DOE-PPPO Proposed Authorized Limits (AL) Volumetric Concentrations available in DOE-PPPO 2011a. This work is provided as an appendix to the Dose Modeling Evaluations and Technical Support Document for the Authorized Limits Request for the C-746-U Landfill at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky (ORISE 2012). The receptors evaluated in ORISE 2012 were selected by the DOE-PPPO for the additional peak dose evaluations. These receptors included a Landfill Worker, Trespasser, Resident Farmer (onsite), Resident Gardener, Recreational User, Outdoor Worker and an Offsite Resident Farmer. The RESRAD (Version 6.5) and RESRAD-OFFSITE (Version 2.5) computer codes were used for the peak dose assessments. Deterministic peak dose assessments were performed for all the receptors and a probabilistic dose assessment was performed only for the Offsite Resident Farmer at the request of the DOE-PPPO. In a deterministic analysis, a single input value results in a single output value. In other words, a deterministic analysis uses single parameter values for every variable in the code. By contrast, a probabilistic approach assigns parameter ranges to certain variables, and the code randomly selects the values for each variable from the parameter range each time it calculates the dose (NRC 2006). The receptor scenarios, computer codes and parameter input files were previously used in ORISE 2012. A few modifications were made to the parameter input files as appropriate for this effort. Some of these changes

  12. Hardening electronic devices against very high total dose radiation environments

    NASA Technical Reports Server (NTRS)

    Buchanan, B.; Shedd, W.; Roosild, S.; Dolan, R.

    1972-01-01

    The possibilities and limitations of hardening silicon semiconductor devices to the high neutron and gamma radiation levels and greater than 10 to the eighth power rads required for the NERVA nuclear engine development are discussed. A comparison is made of the high dose neutron and gamma hardening potential of bipolar, metal insulator semiconductors and junction field effect transistors. Experimental data is presented on device degradation for the high neutron and gamma doses. Previous data and comparisons indicate that the JFET is much more immune to the combined neutron displacement and gamma ionizing effects than other transistor types. Experimental evidence is also presented which indicates that p channel MOS devices may be able to meet the requirements.

  13. Application of Terrestrial Environments in Orion Assessments

    NASA Technical Reports Server (NTRS)

    Barbre, Robert E.

    2016-01-01

    This presentation summarizes the Marshall Space Flight Center Natural Environments Terrestrial and Planetary Environments (TPE) Team support to the NASA Orion space vehicle. The TPE utilizes meteorological data to assess the sensitivities of the vehicle due to the terrestrial environment. The Orion vehicle, part of the Multi-Purpose Crew Vehicle Program, is designed to carry astronauts beyond low-earth orbit and is currently undergoing a series of tests including Exploration Test Flight (EFT) - 1. The presentation describes examples of TPE support for vehicle design and several tests, as well as support for EFT-1 and planning for upcoming Exploration Missions while emphasizing the importance of accounting for the natural environment's impact to the vehicle early in the vehicle's program.

  14. Dietary Assessment in Food Environment Research

    PubMed Central

    Kirkpatrick, Sharon I.; Reedy, Jill; Butler, Eboneé N.; Dodd, Kevin W.; Subar, Amy F.; Thompson, Frances E.; McKinnon, Robin A.

    2015-01-01

    Context The existing evidence on food environments and diet is inconsistent, potentially due in part to heterogeneity in measures used to assess diet. The objective of this review, conducted in 2012–2013, was to examine measures of dietary intake utilized in food environment research. Evidence acquisition Included studies were published from January 2007 through June 2012 and assessed relationships between at least one food environment exposure and at least one dietary outcome. Fifty-one articles were identified using PubMed, Scopus, Web of Knowledge, and PsycINFO; references listed in the papers reviewed and relevant review articles; and the National Cancer Institute's Measures of the Food Environment website. The frequency of the use of dietary intake measures and assessment of specific dietary outcomes was examined, as were patterns of results among studies using different dietary measures. Evidence synthesis The majority of studies used brief instruments, such as screeners or one or two questions, to assess intake. Food frequency questionnaires were used in about a third of studies, one in ten used 24-hour recalls, and fewer than one in twenty used diaries. Little consideration of dietary measurement error was evident. Associations between the food environment and diet were more consistently in the expected direction in studies using less error-prone measures. Conclusions There is a tendency toward the use of brief dietary assessment instruments with low cost and burden rather than more detailed instruments that capture intake with less bias. Use of error-prone dietary measures may lead to spurious findings and reduced power to detect associations. PMID:24355678

  15. Radiation dose reduction in paediatric coronary computed tomography: assessment of effective dose and image quality.

    PubMed

    Habib Geryes, Bouchra; Calmon, Raphael; Khraiche, Diala; Boddaert, Nathalie; Bonnet, Damien; Raimondi, Francesca

    2016-07-01

    To assess the impact of different protocols on radiation dose and image quality for paediatric coronary computed tomography (cCT). From January-2012 to June-2014, 140 children who underwent cCT on a 64-slice scanner were included. Two consecutive changes in imaging protocols were performed: 1) the use of adaptive statistical iterative reconstruction (ASIR); 2) the optimization of acquisition parameters. Effective dose (ED) was calculated by conversion of the dose-length product. Image quality was assessed as excellent, good or with significant artefacts. Patients were divided in three age groups: 0-4, 5-7 and 8-18 years. The use of ASIR combined to the adjustment of scan settings allowed a reduction in the median ED of 58 %, 82 % and 85 % in 0-4, 5-7 and 8-18 years group, respectively (7.3 ± 1.4 vs 3.1 ± 0.7 mSv, 5.5 ± 1.6 vs 1 ± 1.9 mSv and 5.3 ± 5.0 vs 0.8 ± 2.0 mSv, all p < 0,05). Prospective protocol was used in 51 % of children. The reduction in radiation dose was not associated with reduction in diagnostic image quality as assessed by the frequency of coronary segments with excellent or good image quality (88 %). cCT can be obtained at very low radiation doses in children using ASIR, and prospective acquisition with optimized imaging parameters. • Using ASIR allows 25 % to 41 % reduction in the ED. • Prospective protocol is used up to 51 % of children after premedication. • Low dose is possible using ASIR and optimized prospective paediatric cCT.

  16. KSC Launch Pad Flame Trench Environment Assessment

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark R.; Sampson, Jeffrey W.

    2010-01-01

    This report summarizes conditions in the Launch Complex 39 (LC-39) flame trenches during a Space Shuttle Launch, as they have been measured to date. Instrumentation of the flame trench has been carried out by NASA and United Space Alliance for four Shuttle launches. Measurements in the flame trench are planned to continue for the duration of the Shuttle Program. The assessment of the launch environment is intended to provide guidance in selecting appropriate test methods for refractory materials used in the flame trench and to provide data used to improve models of the launch environment in the flame trench.

  17. Assessments for High Dose Radionuclide Therapy Treatment Planning

    SciTech Connect

    Fisher, Darrell R.

    2003-10-01

    Advances in the biotechnology of cell-specific targeting of cancer, and the increased number of clinical trials involving treatment of cancer patients with radiolabeled antibodies, peptides, and similar delivery vehicles have led to an increase in the number of high-dose radionuclide therapy procedures. Optimized radionuclide therapy for cancer treatment is based on the concept of absorbed dose to the dose-limiting normal organ or tissue. The limiting normal tissue is often the red marrow, but it may sometimes be lungs, liver, intestinal tract, or kidneys. Appropriate treatment planning requires assessment of radiation dose to several internal organs and tissues, and usually involves biodistribution studies in the patient using a tracer amount of radionuclide bound to the targeting agent and imaged at sequential time points using a planar gamma camera. Time-activity curves are developed from the imaging data for the major organs tissues of concern, for the whole body, and sometimes for selected tumors. Patient-specific factors often require that dose estimates be customized for each patient. The Food and Drug Administration regulates the experimental use of investigational new drugs and requires reasonable calculation of radiation absorbed dose to the whole body and to critical organs using methods prescribed by the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. Review of high-dose studies in the U.S. and elsewhere shows that 1) some studies are conducted with minimal dosimetry, 2) the marrow dose is difficult to establish and is subject to large uncertainties, and 3) despite the general availability of MIRD software, internal dosimetry methods are often inconsistent from one clinical center to another.

  18. Audio-visual interactions in environment assessment.

    PubMed

    Preis, Anna; Kociński, Jędrzej; Hafke-Dys, Honorata; Wrzosek, Małgorzata

    2015-08-01

    The aim of the study was to examine how visual and audio information influences audio-visual environment assessment. Original audio-visual recordings were made at seven different places in the city of Poznań. Participants of the psychophysical experiments were asked to rate, on a numerical standardized scale, the degree of comfort they would feel if they were in such an environment. The assessments of audio-visual comfort were carried out in a laboratory in four different conditions: (a) audio samples only, (b) original audio-visual samples, (c) video samples only, and (d) mixed audio-visual samples. The general results of this experiment showed a significant difference between the investigated conditions, but not for all the investigated samples. There was a significant improvement in comfort assessment when visual information was added (in only three out of 7 cases), when conditions (a) and (b) were compared. On the other hand, the results show that the comfort assessment of audio-visual samples could be changed by manipulating the audio rather than the video part of the audio-visual sample. Finally, it seems, that people could differentiate audio-visual representations of a given place in the environment based rather of on the sound sources' compositions than on the sound level. Object identification is responsible for both landscape and soundscape grouping.

  19. Integrated Worker Radiation Dose Assessment for the K Basins

    SciTech Connect

    NELSON, J.V.

    1999-10-27

    This report documents an assessment of the radiation dose workers at the K Basins are expected to receive in the process of removing spent nuclear fuel from the storage basins. The K Basins (K East and K West) are located in the Hanford 100K Area.

  20. The Assessment of Effective Dose Equivalent Using Personnel Dosimeters

    NASA Astrophysics Data System (ADS)

    Xu, Xie

    From January 1994, U.S. nuclear plants must develop a technically rigorous approach for determining the effective dose equivalent for their work forces. This dissertation explains concepts associated with effective dose equivalent and describes how to assess effective dose equivalent by using conventional personnel dosimetry measurements. A Monte Carlo computer code, MCNP, was used to calculate photon transport through a model of the human body. Published mathematical phantoms of the human adult male and female were used to simulate irradiation from a variety of external radiation sources in order to calculate organ and tissue doses, as well as effective dose equivalent using weighting factors from ICRP Publication 26. The radiation sources considered were broad parallel photon beams incident on the body from 91 different angles and isotropic point sources located at 234 different locations in contact with or near the body. Monoenergetic photons of 0.08, 0.3, and 1.0 MeV were considered for both sources. Personnel dosimeters were simulated on the surface of the body and exposed to with the same sources. From these data, the influence of dosimeter position on dosimeter response was investigated. Different algorithms for assessing effective dose equivalent from personnel dosimeter responses were proposed and evaluated. The results indicate that the current single-badge approach is satisfactory for most common exposure situations encountered in nuclear plants, but additional conversion factors may be used when more accurate results become desirable. For uncommon exposures involving source situated at the back of the body or source located overhead, the current approach of using multi-badges and assigning the highest dose is overly conservative and unnecessarily expensive. For these uncommon exposures, a new algorithm, based on two dosimeters, one on the front of the body and another one on the back of the body, has been shown to yield conservative assessment of

  1. The Northern Marshall Islands Radiological Survey: data and dose assessments.

    PubMed

    Robison, W L; Noshkin, V E; Conrado, C L; Eagle, R J; Brunk, J L; Jokela, T A; Mount, M E; Phillips, W A; Stoker, A C; Stuart, M L; Wong, K M

    1997-07-01

    Fallout from atmospheric nuclear tests, especially from those conducted at the Pacific Proving Grounds between 1946 and 1958, contaminated areas of the Northern Marshall Islands. A radiological survey at some Northern Marshall Islands was conducted from September through November 1978 to evaluate the extent of residual radioactive contamination. The atolls included in the Northern Marshall Islands Radiological Survey (NMIRS) were Likiep, Ailuk, Utirik, Wotho, Ujelang, Taka, Rongelap, Rongerik, Bikar, Ailinginae, and Mejit and Jemo Islands. The original test sites, Bikini and Enewetak Atolls, were also visited on the survey. An aerial survey was conducted to determine the external gamma exposure rate. Terrestrial (soil, food crops, animals, and native vegetation), cistern and well water samples, and marine (sediment, seawater, fish and clams) samples were collected to evaluate radionuclide concentrations in the atoll environment. Samples were processed and analyzed for 137Cs, 90Sr, 239+240Pu and 241Am. The dose from the ingestion pathway was calculated using the radionuclide concentration data and a diet model for local food, marine, and water consumption. The ingestion pathway contributes 70% to 90% of the estimated dose. Approximately 95% of the dose is from 137Cs. 90Sr is the second most significant radionuclide via ingestion. External gamma exposure from 137Cs accounts for about 10% to 30% of the dose. 239+240Pu and 241Am are the major contributors to dose via the inhalation pathway; however, inhalation accounts for only about 1% of the total estimated dose, based on surface soil levels and resuspension studies. All doses are computed for concentrations decay corrected to 1996. The maximum annual effective dose from manmade radionuclides at these atolls ranges from .02 mSv y(-1) to 2.1 mSv y(-1). The background dose in the Marshall Islands is estimated to be 2.4 mSv y(-1). The combined dose from both background and bomb related radionuclides ranges from slightly

  2. Radiological assessment. A textbook on environmental dose analysis

    SciTech Connect

    Till, J.E.; Meyer, H.R.

    1983-09-01

    Radiological assessment is the quantitative process of estimating the consequences to humans resulting from the release of radionuclides to the biosphere. It is a multidisciplinary subject requiring the expertise of a number of individuals in order to predict source terms, describe environmental transport, calculate internal and external dose, and extrapolate dose to health effects. Up to this time there has been available no comprehensive book describing, on a uniform and comprehensive level, the techniques and models used in radiological assessment. Radiological Assessment is based on material presented at the 1980 Health Physics Society Summer School held in Seattle, Washington. The material has been expanded and edited to make it comprehensive in scope and useful as a text. Topics covered include (1) source terms for nuclear facilities and Medical and Industrial sites; (2) transport of radionuclides in the atmosphere; (3) transport of radionuclides in surface waters; (4) transport of radionuclides in groundwater; (5) terrestrial and aquatic food chain pathways; (6) reference man; a system for internal dose calculations; (7) internal dosimetry; (8) external dosimetry; (9) models for special-case radionuclides; (10) calculation of health effects in irradiated populations; (11) evaluation of uncertainties in environmental radiological assessment models; (12) regulatory standards for environmental releases of radionuclides; (13) development of computer codes for radiological assessment; and (14) assessment of accidental releases of radionuclides.

  3. Technical Note: scuda: A software platform for cumulative dose assessment.

    PubMed

    Park, Seyoun; McNutt, Todd; Plishker, William; Quon, Harry; Wong, John; Shekhar, Raj; Lee, Junghoon

    2016-10-01

    Accurate tracking of anatomical changes and computation of actually delivered dose to the patient are critical for successful adaptive radiation therapy (ART). Additionally, efficient data management and fast processing are practically important for the adoption in clinic as ART involves a large amount of image and treatment data. The purpose of this study was to develop an accurate and efficient Software platform for CUmulative Dose Assessment (scuda) that can be seamlessly integrated into the clinical workflow. scuda consists of deformable image registration (DIR), segmentation, dose computation modules, and a graphical user interface. It is connected to our image PACS and radiotherapy informatics databases from which it automatically queries/retrieves patient images, radiotherapy plan, beam data, and daily treatment information, thus providing an efficient and unified workflow. For accurate registration of the planning CT and daily CBCTs, the authors iteratively correct CBCT intensities by matching local intensity histograms during the DIR process. Contours of the target tumor and critical structures are then propagated from the planning CT to daily CBCTs using the computed deformations. The actual delivered daily dose is computed using the registered CT and patient setup information by a superposition/convolution algorithm, and accumulated using the computed deformation fields. Both DIR and dose computation modules are accelerated by a graphics processing unit. The cumulative dose computation process has been validated on 30 head and neck (HN) cancer cases, showing 3.5 ± 5.0 Gy (mean±STD) absolute mean dose differences between the planned and the actually delivered doses in the parotid glands. On average, DIR, dose computation, and segmentation take 20 s/fraction and 17 min for a 35-fraction treatment including additional computation for dose accumulation. The authors developed a unified software platform that provides accurate and efficient monitoring of

  4. Distributed optical fibre temperature measurements in a low dose rate radiation environment based on Rayleigh backscattering

    NASA Astrophysics Data System (ADS)

    Faustov, A.; Gussarov, A.; Wuilpart, M.; Fotiadi, A. A.; Liokumovich, L. B.; Kotov, O. I.; Zolotovskiy, I. O.; Tomashuk, A. L.; Deschoutheete, T.; Mégret, P.

    2012-04-01

    On-line monitoring of environmental conditions in nuclear facilities is becoming a more and more important problem. Standard electronic sensors are not the ideal solution due to radiation sensitivity and difficulties in installation of multiple sensors. In contrast, radiation-hard optical fibres can sustain very high radiation doses and also naturally offer multi-point or distributed monitoring of external perturbations. Multiple local electro-mechanical sensors can be replaced by just one measuring fibre. At present, there are over four hundred operational nuclear power plants (NPPs) in the world 1. Operating experience has shown that ineffective control of the ageing degradation of major NPP components can threaten plant safety and also plant life. Among those elements, cables are vital components of I&C systems in NPPs. To ensure their safe operation and predict remaining life, environmental monitoring is necessary. In particular, temperature and radiation dose are considered to be the two most important parameters. The aim of this paper is to assess experimentally the feasibility of optical fibre temperature measurements in a low doserate radiation environment, using a commercially available reflectometer based on Rayleigh backscattering. Four different fibres were installed in the Sub-Pile Room of the BR2 Material testing nuclear reactor in Mol, Belgium. This place is man-accessible during the reactor shut-down, allowing easy fibre installation. When the reactor operates, the dose-rates in the room are in a range 0.005-5 Gy/h with temperatures of 40-60 °C, depending on the location. Such a surrounding is not much different to some "hot" environments in NPPs, where I&C cables are located.

  5. Dose Assessments to the Hands of Radiopharmaceutical Workers

    SciTech Connect

    Ilas, Dan; Eckerman, Keith F; Sherbini, Sami; Karagiannis, Harriet

    2008-01-01

    This paper describes the characterization of radiation doses to the hands of nuclear medicine technicians resulting from the handling of radiopharmaceuticals. Radiation monitoring using ring dosimeters indicates that finger dosimeters may overestimate or underestimate the radiation doses to the skin that are used to show compliance with applicable regulations depending on the nature of the particular procedure and the radioisotope being handled. To better understand the parameters governing the absorbed dose distributions, a detailed model of the hands was created and used in Monte Carlo simulations of selected nuclear medicine procedures. Simulations on realistic configurations typical for workers handling radiopharmaceuticals were performed for a range of energies of the source photons. The lack of charged-particle equilibrium necessitated full photon-electron coupled transport calculations. The results show that the dose to different regions of the fingers can differ substantially from the dosimeters' readings when the dosimeters are located at the base of the finger. We tried to identify consistent patterns that relate the actual dose to the dosimeter readings. These patterns depend on the specific work conditions and can be used to better assess the absorbed dose to different regions of the exposed skin.

  6. Dose estimates for the solid waste performance assessment

    SciTech Connect

    Rittman, P.D.

    1994-08-30

    The Solid Waste Performance Assessment calculations by PNL in 1990 were redone to incorporate changes in methods and parameters since then. The ten scenarios found in their report were reduced to three, the Post-Drilling Resident, the Post-Excavation Resident, and an All Pathways Irrigator. In addition, estimates of population dose to people along the Columbia River are also included. The attached report describes the methods and parameters used in the calculations, and derives dose factors for each scenario. In addition, waste concentrations, ground water concentrations, and river water concentrations needed to reach the performance objectives of 100 mrem/yr and 500 person-rem/yr are computed. Internal dose factors from DOE-0071 were applied when computing internal dose. External dose rate factors came from the GENII Version 1.485 software package. Dose calculations were carried out on a spreadsheet. The calculations are described in detail in the report for 63 nuclides, including 5 not presently in the GENII libraries. The spreadsheet calculations were checked by comparison with GENII, as described in Appendix D.

  7. TSD-DOSE: A radiological dose assessment model for treatment, storage, and disposal facilities

    SciTech Connect

    Pfingston, M.; Arnish, J.; LePoire, D.; Chen, S.-Y.

    1998-10-14

    Past practices at US Department of Energy (DOE) field facilities resulted in the presence of trace amounts of radioactive materials in some hazardous chemical wastes shipped from these facilities. In May 1991, the DOE Office of Waste Operations issued a nationwide moratorium on shipping all hazardous waste until procedures could be established to ensure that only nonradioactive hazardous waste would be shipped from DOE facilities to commercial treatment, storage, and disposal (TSD) facilities. To aid in assessing the potential impacts of shipments of mixed radioactive and chemically hazardous wastes, a radiological assessment computer model (or code) was developed on the basis of detailed assessments of potential radiological exposures and doses for eight commercial hazardous waste TSD facilities. The model, called TSD-DOSE, is designed to incorporate waste-specific and site-specific data to estimate potential radiological doses to on-site workers and the off-site public from waste-handling operations at a TSD facility. The code is intended to provide both DOE and commercial TSD facilities with a rapid and cost-effective method for assessing potential human radiation exposures from the processing of chemical wastes contaminated with trace amounts of radionuclides.

  8. Assessment of radiocarbon in the Savannah River Site Environment

    SciTech Connect

    Carlton, W.H.; Evans, A.G.; Murphy, C.E. Jr.; Tuck, D.M.

    1993-03-01

    This report is a radiological assessment of {sup 14}C releases from the Savannah River Site. During the operation of five production reactors {sup 14}C has been produced at SRS. Approximately 3000 curies have been released to the atmosphere but there are no recorded releases to surface waters. Once released, the {sup 14}C joins the carbon cycle and a portion enters the food chain. The overall radiological impact of SRS releases on the offsite maximum individual can be characterized by a dose of 1.1 mrem, compared with a dose of 12,960 mrem from non-SRS sources during the same period of time. Releases of {sup 14}C have resulted in a negligible risk to the environment and the population it supports.

  9. Assessment of radiocarbon in the Savannah River Site Environment

    SciTech Connect

    Carlton, W.H.; Evans, A.G.; Murphy, C.E. Jr.; Tuck, D.M.

    1993-03-01

    This report is a radiological assessment of [sup 14]C releases from the Savannah River Site. During the operation of five production reactors [sup 14]C has been produced at SRS. Approximately 3000 curies have been released to the atmosphere but there are no recorded releases to surface waters. Once released, the [sup 14]C joins the carbon cycle and a portion enters the food chain. The overall radiological impact of SRS releases on the offsite maximum individual can be characterized by a dose of 1.1 mrem, compared with a dose of 12,960 mrem from non-SRS sources during the same period of time. Releases of [sup 14]C have resulted in a negligible risk to the environment and the population it supports.

  10. Assessment of out-of-field absorbed dose and equivalent dose in proton fields

    SciTech Connect

    Clasie, Ben; Wroe, Andrew; Kooy, Hanne; Depauw, Nicolas; Flanz, Jay; Paganetti, Harald; Rosenfeld, Anatoly

    2010-01-15

    . Conclusions: The dose deposited immediately downstream of the primary field, in these cases, is dominated by internally produced neutrons; therefore, scattered and scanned fields may have similar risk of second cancer in this region. The authors confirm that there is a reduction in the out-of-field dose in active scanning but the effect decreases with depth. GEANT4 is suitable for simulating the dose deposited outside the primary field. The agreement with measurements is comparable to or better than the agreement reported for other implementations of Monte Carlo models. Depending on the position, the absorbed dose outside the primary field is dominated by contributions from primary protons that may or may not have scattered in the brass collimating devices. This is noteworthy as the quality factor of the low LET protons is well known and the relative dose risk in this region can thus be assessed accurately.

  11. TSD-DOSE : a radiological dose assessment model for treatment, storage, and disposal facilities.

    SciTech Connect

    Pfingston, M.

    1998-12-23

    In May 1991, the U.S. Department of Energy (DOE), Office of Waste Operations, issued a nationwide moratorium on shipping slightly radioactive mixed waste from DOE facilities to commercial treatment, storage, and disposal (TSD) facilities. Studies were subsequently conducted to evaluate the radiological impacts associated with DOE's prior shipments through DOE's authorized release process under DOE Order 5400.5. To support this endeavor, a radiological assessment computer code--TSD-DOSE (Version 1.1)--was developed and issued by DOE in 1997. The code was developed on the basis of detailed radiological assessments performed for eight commercial hazardous waste TSD facilities. It was designed to utilize waste-specific and site-specific data to estimate potential radiological doses to on-site workers and the off-site public from waste handling operations at a TSD facility. The code has since been released for use by DOE field offices and was recently used by DOE to evaluate the release of septic waste containing residual radioactive material to a TSD facility licensed under the Resource Conservation and Recovery Act. Revisions to the code were initiated in 1997 to incorporate comments received from users and to increase TSD-DOSE's capability, accuracy, and flexibility. These updates included incorporation of the method used to estimate external radiation doses from DOE's RESRAD model and expansion of the source term to include 85 radionuclides. In addition, a detailed verification and benchmarking analysis was performed.

  12. Designing Assessments and Assessing Designs in Virtual Educational Environments

    ERIC Educational Resources Information Center

    Hickey, Daniel T.; Ingram-Goble, Adam A.; Jameson, Ellen M.

    2009-01-01

    This study used innovative assessment practices to obtain and document broad learning outcomes for a 15-hour game-based curriculum in Quest Atlantis, a multi-user virtual environment that supports school-based participation in socio scientific inquiry in ecological sciences. Design-based methods were used to refine and align the enactment of…

  13. Designing Assessments and Assessing Designs in Virtual Educational Environments

    ERIC Educational Resources Information Center

    Hickey, Daniel T.; Ingram-Goble, Adam A.; Jameson, Ellen M.

    2009-01-01

    This study used innovative assessment practices to obtain and document broad learning outcomes for a 15-hour game-based curriculum in Quest Atlantis, a multi-user virtual environment that supports school-based participation in socio scientific inquiry in ecological sciences. Design-based methods were used to refine and align the enactment of…

  14. Fetal Assessment before and after Dosing with Buprenorphine or Methadone

    PubMed Central

    Salisbury, Amy L.; Coyle, Mara G.; O’Grady, Kevin E.; Heil, Sarah H.; Martin, Peter R.; Stine, Susan M.; Kaltenbach, Karol; Weninger, Manfred; Jones, Hendrée E.

    2014-01-01

    Aim To determine pre- and post-dosing effects of prenatal methadone compared to buprenorphine on fetal well-being. Design A secondary analysis of data derived from the Maternal Opioid Treatment: Human Experimental Research (MOTHER) study, a double-blind, double-dummy, randomized clinical trial. Setting Six United States sites and one European site that provided comprehensive opioid-dependence treatment to pregnant women. Participants 81 of the 131 opioid-dependent pregnant women completing the MOTHER clinical trial, assessed between 31 and 33 weeks of gestation. Measurements Two fetal assessments were conducted, once before and once after study medication dosing. Measures included mean fetal heart rate (FHR), number of FHR accelerations, FHR reactivity in the fetal non-stress test (NST), and biophysical profile (BPP) score. Findings Significant group differences were found for number of FHR accelerations, non-reactive NST, and BPP scores (all Ps < 0.05). There were no significant group differences before time of dosing. Significant decreases (all Ps < 0.05) occurred from pre- to post-dose assessment for mean FHR, FHR accelerations, reactive NST, and fetal movement. The decrease in accelerations and reactive NST were only significant for fetuses in the methadone group and this resulted in a significantly lower likelihood of a reactive NST compared to fetuses in the buprenorphine group. Conclusion Buprenorphine compared with methadone appears to result in less suppression of mean fetal heart rate, fetal heart rate reactivity, and the biophysical profile score after medication dosing and provide support for the relative safety of buprenorphine when fetal indices are considered as part of the complete risk-benefit ratio. PMID:23106925

  15. Fetal assessment before and after dosing with buprenorphine or methadone.

    PubMed

    Salisbury, Amy L; Coyle, Mara G; O'Grady, Kevin E; Heil, Sarah H; Martin, Peter R; Stine, Susan M; Kaltenbach, Karol; Weninger, Manfred; Jones, Hendrée E

    2012-11-01

    To determine pre- and post-dosing effects of prenatal methadone compared to buprenorphine on fetal wellbeing. A secondary analysis of data derived from the Maternal Opioid Treatment: Human Experimental Research (MOTHER) study, a double-blind, double-dummy, randomized clinical trial. Six United States sites and one European site that provided comprehensive opioid-dependence treatment to pregnant women. Eighty-one of the 131 opioid-dependent pregnant women completing the MOTHER clinical trial, assessed between 31 and 33 weeks of gestation. Two fetal assessments were conducted, once before and once after study medication dosing. Measures included mean fetal heart rate (FHR), number of FHR accelerations, FHR reactivity in the fetal non-stress test (NST) and biophysical profile (BPP) score. Significant group differences were found for number of FHR accelerations, non-reactive NST and BPP scores (all Ps < 0.05). There were no significant group differences before time of dosing. Significant decreases (all Ps < 0.05) occurred from pre- to post-dose assessment for mean FHR, FHR accelerations, reactive NST and fetal movement. The decrease in accelerations and reactive NST were significant only for fetuses in the methadone group, and this resulted in a significantly lower likelihood of a reactive NST compared to fetuses in the buprenorphine group. Buprenorphine compared with methadone appears to result in less suppression of mean fetal heart rate, fetal heart rate reactivity and the biophysical profile score after medication dosing and these findings provide support for the relative safety of buprenorphine when fetal indices are considered as part of the complete risk-benefit ratio. © 2012 The Authors, Addiction © 2012 Society for the Study of Addiction.

  16. Assessment of strontium in the Savannah River Site environment

    SciTech Connect

    Carlton, W.H.; Evans, A.G.; Geary, L.A.; Murphy, C.E. Jr.; Strom, R.N.

    1992-12-31

    This document on strontium is published as a part of the Radiological Assessment Program (RAP). It is the sixth in a series of eight documents on individual radioisotopes released to the environment as a result of SRS (Savannah River Site) operations. Strontium exists in the environment as a result of above-ground nuclear weapons tests, the Chernobyl accident, the destruction of satellite Cosmos 954, small releases from reactors and reprocessing plants, and the operation of industrial, medical, and educational facilities. Strontium has been produced at SRS during the operation of 5 production reactors. About 300 curies of radiostrontium were released into streams in the late 50s and 60s, primarily from leaking fuel elements in reactor storage basins. Smaller quantities were released from the fuel reprocessing operations. About 400 Ci were released to seepage basins. A much smaller quantity, about 2 Ci, was released to the atmosphere. The overall radiological impact of SRS releases on the offsite maximum individual can be characterized by total doses of 6.2 mrem (atmospheric) and 1.4 mrem (liquid), compared with a dose of 12,960 mrem from non-SRS sources during the same period of time. Radiostrontium releases have resulted in a negligible risk to the environment and the population it supports.

  17. Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology.

    PubMed

    Xapsos, M A; Stauffer, C; Phan, A; McClure, S S; Ladbury, R L; Pellish, J A; Campola, M J; LaBel, K A

    2017-01-01

    Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the radiation design margin concept with one of failure probability during a mission.

  18. Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology

    NASA Technical Reports Server (NTRS)

    Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; LaBel, K. A.

    2015-01-01

    Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the design margin concept with one of failure probability.

  19. Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology

    NASA Technical Reports Server (NTRS)

    Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; LaBel, K. A.

    2016-01-01

    Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the radiation design margin concept with one of failure probability during a mission.

  20. Assessment of patient dose in medical processes by in-vivo dose measuring devices: A review

    NASA Astrophysics Data System (ADS)

    Tuncel, Nina

    2016-11-01

    In-vivo dosimetry (IVD) in medicine especially in radiation therapy is a well-established and recommended procedure for the estimation of the dose delivered to a patient during the radiation treatment. It became even more important with the emerging use of new and more complex radiotherapy techniques such as intensity-modulated or image-guided radiation therapy. While IVD has been used in brachytherapy for decades and the initial motivation for performing was mainly to assess doses to organs at risk by direct measurements, it is now possible to calculate 3D for detection of deviations or errors. In-vivo dosimeters can be divided into real-time and passive detectors that need some finite time following irradiation for their analysis. They require a calibration against a calibrated ionization chamber in a known radiation field. Most of these detectors have a response that is energy and/or dose rate dependent and consequently require adjustments of the response to account for changes in the actual radiation conditions compared to the calibration situation. Correction factors are therefore necessary to take. Today, the most common dosimeters for patients' dose verification through in-vivo measurements are semiconductor diodes, thermo-luminescent dosimeters, optically stimulated luminescence dosimeters, metal-oxide-semiconductor field-effect transistors and plastic scintillator detectors with small outer diameters.

  1. Can the Equivalent Sphere Model Approximate Organ Doses in Space Radiation Environments?

    NASA Technical Reports Server (NTRS)

    Zi-Wei, Lin

    2007-01-01

    In space radiation calculations it is often useful to calculate the dose or dose equivalent in blood-forming organs (BFO). the skin or the eye. It has been customary to use a 5cm equivalent sphere to approximate the BFO dose. However previous studies have shown that a 5cm sphere gives conservative dose values for BFO. In this study we use a deterministic radiation transport with the Computerized Anatomical Man model to investigate whether the equivalent sphere model can approximate organ doses in space radiation environments. We find that for galactic cosmic rays environments the equivalent sphere model with an organ-specific constant radius parameter works well for the BFO dose equivalent and marginally well for the BFO dose and the dose equivalent of the eye or the skin. For solar particle events the radius parameters for the organ dose equivalent increase with the shielding thickness, and the model works marginally for BFO but is unacceptable for the eye or the skin The ranges of the radius parameters are also shown and the BFO radius parameters are found to be significantly larger than 5 cm in all eases.

  2. Intraoperative fluoroscopic dose assessment in prostate brachytherapy patients.

    PubMed

    Reed, Daniel R; Wallner, Kent E; Narayanan, Sreeram; Sutlief, Steve G; Ford, Eric C; Cho, Paul S

    2005-09-01

    To evaluate a fluoroscopy-based intraoperative dosimetry system to guide placement of additional sources to underdosed areas, and perform computed tomography (CT) verification. Twenty-six patients with prostate carcinoma treated with either I-125 or Pd-103 brachytherapy at the Puget Sound VA using intraoperative postimplant dosimetry were analyzed. Implants were performed by standard techniques. After completion of the initial planned brachytherapy procedure, the initial fluoroscopic intraoperative dose reconstruction analysis (I-FL) was performed with three fluoroscopic images acquired at 0 (AP), +15, and -15 degrees. Automatic seed identification was performed and the three-dimensional (3D) seed coordinates were computed and imported into VariSeed for dose visualization. Based on a 3D assessment of the isodose patterns additional seeds were implanted, and the final fluoroscopic intraoperative dose reconstruction was performed (FL). A postimplant computed tomography (CT) scan was obtained after the procedure and dosimetric parameters and isodose patterns were analyzed and compared. An average of 4.7 additional seeds were implanted after intraoperative analysis of the dose coverage (I-FL), and a median of 5 seeds. After implantation of additional seeds the mean V100 increased from 89% (I-FL) to 92% (FL) (p < 0.001). In I-125 patients an improvement from 91% to 94% (p = 0.01), and 87% to 93% (p = 0.001) was seen for Pd-103. The D90 increased from 105% (I-FL) to 122% (FL) (p < 0.001) for I-125, and 92% (I-FL) to 102% (FL) (p = 0.008) for Pd-103. A minimal change occurred in the R100 from a mean of 0.32 mL (I-FL) to 0.6 mL (FL) (p = 0.19). No statistical difference was noted in the R100 (rectal volume receiving 100% of the prescribed dose) between the two techniques. The rate of adverse isodose patterns decreased between I-FL and FL from 42% to 8%, respectively. The I-125 patients demonstrated a complete resolution of adverse isodose patterns after the initial isodose

  3. Radiological environmental dose assessment methods and compliance dose results for 2015 operations at the Savannah River Site

    SciTech Connect

    Jannik, G. T.; Dixon, K. L.

    2016-09-01

    This report presents the environmental dose assessment methods and the estimated potential doses to the offsite public from 2015 Savannah River Site (SRS) atmospheric and liquid radioactive releases. Also documented are potential doses from special-case exposure scenarios - such as the consumption of deer meat, fish, and goat milk.

  4. Collaborative Work Environment for Operational Conjunction Assessment

    NASA Astrophysics Data System (ADS)

    Laporte, F.; Christy, S.

    Conjunction Messages (CM) provided by JSpOC are complete and valuable data to evaluate the level of risk of conjunctions, decide and choose avoidance actions. Nevertheless, conjunction assessment remains a difficult task which requires Middle Man between the CM provider (JSpOC) and Owner/Operators. Operational collision threat characterization is now an essential component of space mission operations. Most spacecraft operators have some sort of a process to evaluate and mitigate high-risk conjunction events. As the size of the space object catalog increases, satellite operators will be faced with more conjunction events to evaluate. Thus more sophisticated collision threat characterization and collision avoidance strategies must be implemented thought Middle Man entities. CAESAR (Conjunction Analysis and Evaluation Service, Alerts and Recommendations) is the French Middle Man. CAESAR relies on a collaborative work environment between all members of CAESAR team and its subscribers. For CAESAR, the collaborative work environment is based on JAC software and a dedicated secure webserver SpOD Space Operational Data. JAC software is not the Main Flight Dynamics (FD) software used by CAESAR team, but it is a light friendly CM dedicated software to be used on a laptop by on-call teams or support dialogue between Middle Man and FD teams. The dedicated secure webserver is a key element to share data and information between actors. This paper presents the main feedbacks from CAESAR team operational experience with regards to its collaborative work environment components: - JAC software which is not a classical Flight Dynamics software, its MMI is designed to be very quickly taken over (by teams not using it on daily basis) while also offering all the expertise levels required by the Middle Man team. JAC is used by CAESAR on-call team and all FD teams who subscribed to CAESAR. JAC is also distributed by CNES and therefore already used by some operational teams for Conjunction

  5. Cone beam computed tomography radiation dose and image quality assessments.

    PubMed

    Lofthag-Hansen, Sara

    2010-01-01

    Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and

  6. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    PubMed Central

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-01-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  7. Fetal dose assessment from invasive special procedures by Monte Carlo methods.

    PubMed

    Metzger, R L; Van Riper, K A

    1999-08-01

    The assessment of fetal dose from a special procedure in the clinical environment is difficult as patient size, fluoroscopic beam motion, and imaging sequences vary significantly from study to study. Fetal dose is particularly difficult to estimate when the fetus is exposed partially or totally to scatter radiation from images taken in other locations of the mother's body. A method to reliably estimate fetal dose has been developed by using template based input files for the Monte Carlo radiation transport code MCNP. Female patient phantoms at 0, 3, 6, and 9 months of pregnancy and source terms for common diagnostic tube potentials are used to rapidly build an input file for MCNP. The phantoms can be easily modified to fit patient shape. The geometry and beam location for each type of image acquired (i.e. fluoroscopy, spot filming, etc.) is verified by the use of a 3D visualization code (Sabrina). MCNP is then run to estimate the dose to the embryo/fetus and the exposure to skin entrance (ESE) for the beam being modeled. The actual ESE for the beam is then measured with ion chambers and the fetal dose is determined from the MCNP supplied ratio of ESE to fetal dose. Runs are made for each type of imaging and the doses are summed for the total fetal dose. For most procedures, the method can provide an estimate of the fetal dose within one day of the study. The method can also be used to prospectively model a study in order to choose imaging sequences that will minimize fetal dose.

  8. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico.

    PubMed

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-09-30

    Determining ionizing radiation in a geographic area serves to assess its effects on a population's health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h(-1). At the same sites, 48 soil samples were taken to obtain the activity concentrations of (226)Ra, (232)Th and (40)K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h(-1). Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg(-1), for (226)Ra, (232)Th and (40)K, respectively. From the analysis, the spatial distribution of (232)Th, (226)Ra and (40)K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize.

  9. Dose assessment during complex meteorology in the Texas panhandle

    SciTech Connect

    Schalk, W.W. III; Foster, K.

    1989-06-01

    Recently the opportunity arose to perform a radiological assessment during complex meteorological conditions in the panhandle region of Texas. The complex conditions consisted of the formation of an occluded front from a trof and its passage from the southwest, a southwest to northeast trof formation northwest of the assessment point, an area of low pressure centered to the west, and severe thunderstorms at the assessment time at and near the study region while under watch box notification. Most of these features can be seen on the 17 May 89 surface analysis. The assessment included a normalized release rate of tritiated water vapor in which the 50 year committed effective whole body integrated air dose plots were compared over time. 2 refs., 2 figs.

  10. Assessment of Technetium in the Savannah River Site Environment

    SciTech Connect

    Carlton, W.H.; Denham, M.; Evans, A.G.

    1993-07-01

    Assessment of Technetium in the Savannah River Site Environment is the last in a series of eight documents on individual radioisotopes released to the environment as a result of SRS operations. The earlier documents describe the environmental consequences of tritium cesium, iodine, uranium plutonium, strontium, and carbon. Technetium transport and metabolism have been studied by the nuclear industry because it is a fission product of uranium, and by the medical community because {sup 99m}Tc commonly is used as a diagnostic imaging agent in nuclear medicine. Technetium has been produced at SRS during the operation of five production reactors. The only isotope with environmental significance is {sup 99}Tc. Because of the small activities of {sup 99}Tc relative to other fission products, such as {sup 90}Sr and {sup 137}Cs, no measurements were made of releases to either the atmosphere or surface waters. Dose calculations were made in this document using conservative estimates of atmospheric releases and from a few measurements of {sup 99}Tc concentrations in the Savannah River. Technetium in groundwater has been found principally in the vicinity of the separation areas seepage basins. Technetium is soluble in water and follows groundwater flow with little retardation. While most groundwater samples are negative or show little technetium a few samples have levels slightly above the limits set by the EPA for drinking water. The overall radiological impact of SRS {sup 99}Tc releases on the offsite maximally exposed individual during 38 years of operations can be characterized by maximum individual doses of 0.1 mrem (atmospheric) and 0.8 mrem (liquid), compared with a dose of 13,680 mrem from non-SRS sources during the same time period. Technetium releases have resulted in a negligible risk to the environment and the population it supports.

  11. Natural radionuclides in clay deposits: concentration and dose assessment.

    PubMed

    Khater, Ashraf E M; Al-Mobark, Layla H; Aly, Amany A; Al-Omran, A M

    2013-09-01

    Clays are among the most important industrially used minerals. Three potential clay mineral mining sites in Saudi Arabia were chosen, and 21 clay deposit samples were collected. The activity concentrations (average±standard deviation) of the naturally occurring radioactive materials (NORMs), (238)U, (226)Ra, (232)Th, (228)Ra and (40)K, were 49±20, 47±23, 34±11, 40±20 and 751 Bq kg(-1), respectively. The radiation dose assessments (e.g., absorbed dose rate, nGy h(-1); effective dose equivalent, µSv y(-1); and effective dose rate due to dust inhalation, µSv y(-1)) and hazardous indices (e.g., radium equivalent [Ra-eq] value, external hazardous index [Hex], internal hazardous index [Hin] and representative gamma level [Iγ]) were calculated. The wide variations in the activity concentrations of the NORMs according to sampling region could be due to the origin of the geological formation and the geochemical behaviour of the NORMs. Based on calculated hazardous (external and internal) indices, there were no expected radiological hazardous impacts of using clay deposits as building materials.

  12. TRIAGE DOSE ASSESSMENT FOR PARTIAL-BODY EXPOSURE: DICENTRIC ANALYSIS

    PubMed Central

    Moroni, Maria; Pellmar, Terry C.

    2009-01-01

    Partial-body biodosimetry is likely to be required after a radiological or nuclear exposure. Clinical signs and symptoms, distribution of dicentrics in circulating blood cells, organ-specific biomarkers, physical signals in teeth and nails all can provide indications of non-homogeneous exposures. Organ specific biomarkers may provide early warning regarding physiological systems at risk after radiation injury. Use of a combination of markers and symptoms will be needed for clinical insights for therapeutic approaches. Analysis of dicentrics, a marker specific for radiation injury, is the “Gold standard” of biodosimetry and can reveal partial-body exposures. Automation of sample processing for dicentric analysis can increase throughput with customization of off-the-shelf technologies for cytogenetic sample processing and information management. Automated analysis of the metaphase spreads is currently limited but improvements are in development. Our efforts bridge the technological gaps to allow the use of dicentric chromosome assay (DCA) for risk-based stratification of mass casualties. This article summarizes current knowledge on partial-body cytogenetic dose assessment synthesizing information leading to the proposal of an approach to triage dose prediction in radiation mass casualties, based on equivalent whole-body doses under partial-body exposure conditions and assesses the validity of using this model. An initial screening using only 20 metaphase spreads per subject can confirm irradiation above 2-Gy. A subsequent increase to 50 metaphases improves dose determination to allow risk stratification for clinical triage. Metaphases evaluated for inhomogeneous distribution of dicentrics can reveal partial-body exposures. We tested the validity of this approach in an in vitro model that simulates partial-body irradiation by mixing irradiated and un-irradiated lymphocytes in various proportions. Our preliminary results support the notion that this approach will

  13. Designing Assessments and Assessing Designs in Virtual Educational Environments

    NASA Astrophysics Data System (ADS)

    Hickey, Daniel T.; Ingram-Goble, Adam A.; Jameson, Ellen M.

    2009-04-01

    This study used innovative assessment practices to obtain and document broad learning outcomes for a 15-hour game-based curriculum in Quest Atlantis, a multi-user virtual environment that supports school-based participation in socio scientific inquiry in ecological sciences. Design-based methods were used to refine and align the enactment of virtual narrative and scientific investigations to a challenging problem solving assessment and indirectly to achievement test items that were independent of the curriculum. In study one, one-sixth grade teacher used the curriculum in two of his classes and obtained larger gains in understanding and achievement than his two other classes, which used an expository text to learn the same concepts and skills. Further treatment refinements were carried out, and two forms of virtual formative feedback were introduced. In study two, the same teacher used the curriculum in all four of his classes; the revised curriculum resulted in even larger gains in understanding and achievement. Gains averaged 1.1 SD and 0.4 SD, respectively, with greater gains shown for students who engaged more with formative feedback. Principles for assessing designs and designing assessments in virtual environments are presented.

  14. Simulation-based computation of dose to humans in radiological environments

    SciTech Connect

    Breazeal, N.L.; Davis, K.R.; Watson, R.A.; Vickers, D.S.; Ford, M.S.

    1996-03-01

    The Radiological Environment Modeling System (REMS) quantifies dose to humans working in radiological environments using the IGRIP (Interactive Graphical Robot Instruction Program) and Deneb/ERGO simulation software. These commercially available products are augmented with custom C code to provide radiation exposure information to, and collect radiation dose information from, workcell simulations. Through the use of any radiation transport code or measured data, a radiation exposure input database may be formulated. User-specified IGRIP simulations utilize these databases to compute and accumulate dose to programmable human models operating around radiation sources. Timing, distances, shielding, and human activity may be modeled accurately in the simulations. The accumulated dose is recorded in output files, and the user is able to process and view this output. The entire REMS capability can be operated from a single graphical user interface.

  15. Exposure and dose assessment to particle components among an elderly population

    NASA Astrophysics Data System (ADS)

    Almeida-Silva, M.; Almeida, S. M.; Pegas, P. N.; Nunes, T.; Alves, C. A.; Wolterbeek, H. T.

    2015-02-01

    People spend the majority of their time indoors and the composition and toxicity of indoor particles is very complex and present significant differences comparing with outdoor aerosols. Consequently, ambient particles cannot represent a real exposure. The aim of this work was to determine the daily exposure and the daily inhaled dose to particle components of elders living in Elderly Care Centers. A questionnaire was applied to 193 institutionalized elders in order to achieve their daily time pattern and to define the micro-environments where PM10 and its components (carbonaceous components and trace elements) were assessed. Daily exposure was calculated by integrating the elder's time spend in each micro-environment and the concentration of the pollutants for the period of interest. This parameter, together with the inhalation rate and the standard body weight, were used to calculate the daily inhaled dose. PM10 daily exposure and daily inhaled dose ranged between 11 - 16 μg m-3 and 20 × 10-3 - 28 × 10-3 μg kg-1, respectively. This work not only allowed a fully quantification of the magnitude of the elders exposure, but also showed that the assessment of the integrated exposure to PM components is determinant to accomplish the dose inhaled by elders living in ECCs.

  16. Source term calculations for assessing radiation dose to equipment

    SciTech Connect

    Denning, R.S.; Freeman-Kelly, R.; Cybulskis, P.; Curtis, L.A.

    1989-07-01

    This study examines results of analyses performed with the Source Term Code Package to develop updated source terms using NUREG-0956 methods. The updated source terms are to be used to assess the adequacy of current regulatory source terms used as the basis for equipment qualification. Time-dependent locational distributions of radionuclides within a containment following a severe accident have been developed. The Surry reactor has been selected in this study as representative of PWR containment designs. Similarly, the Peach Bottom reactor has been used to examine radionuclide distributions in boiling water reactors. The time-dependent inventory of each key radionuclide is provided in terms of its activity in curies. The data are to be used by Sandia National Laboratories to perform shielding analyses to estimate radiation dose to equipment in each containment design. See NUREG/CR-5175, Beta and Gamma Dose Calculations for PWR and BWR Containments.'' 6 refs., 11 tabs.

  17. ARAC: A flexible real-time dose consequence assessment system

    SciTech Connect

    Ellis, J.S.; Sullivan, T.J.

    1993-10-07

    Since its beginning, the Atmospheric Release Advisory Capability (ARAC), an emergency radiological dose assessment service of the US Government, has been called on to do consequence assessments for releases into the atmosphere of radionuclides and a variety of other substances. Some of the more noteworthy emergency responses have been for the Three Mile Island and Chernobyl nuclear power reactor accidents, and more recently, for a cloud of gases from a rail-car spill into the Sacramento river of the herbicide metam sodium, smoke from hundreds of burning oil wells in Kuwait, and ash clouds from the eruption of Mt. Pinatubo. The spatial scales of these responses range from local, to regional, to global, and the response periods from hours, to weeks, to months. Because of the variety of requirements of each unique assessment, ARAC has developed and maintains a flexible system of people, computer software and hardware.

  18. Smartphone apps for calculating insulin dose: a systematic assessment.

    PubMed

    Huckvale, Kit; Adomaviciute, Samanta; Prieto, José Tomás; Leow, Melvin Khee-Shing; Car, Josip

    2015-05-06

    Medical apps are widely available, increasingly used by patients and clinicians, and are being actively promoted for use in routine care. However, there is little systematic evidence exploring possible risks associated with apps intended for patient use. Because self-medication errors are a recognized source of avoidable harm, apps that affect medication use, such as dose calculators, deserve particular scrutiny. We explored the accuracy and clinical suitability of apps for calculating medication doses, focusing on insulin calculators for patients with diabetes as a representative use for a prevalent long-term condition. We performed a systematic assessment of all English-language rapid/short-acting insulin dose calculators available for iOS and Android. Searches identified 46 calculators that performed simple mathematical operations using planned carbohydrate intake and measured blood glucose. While 59% (n = 27/46) of apps included a clinical disclaimer, only 30% (n = 14/46) documented the calculation formula. 91% (n = 42/46) lacked numeric input validation, 59% (n = 27/46) allowed calculation when one or more values were missing, 48% (n = 22/46) used ambiguous terminology, 9% (n = 4/46) did not use adequate numeric precision and 4% (n = 2/46) did not store parameters faithfully. 67% (n = 31/46) of apps carried a risk of inappropriate output dose recommendation that either violated basic clinical assumptions (48%, n = 22/46) or did not match a stated formula (14%, n = 3/21) or correctly update in response to changing user inputs (37%, n = 17/46). Only one app, for iOS, was issue-free according to our criteria. No significant differences were observed in issue prevalence by payment model or platform. The majority of insulin dose calculator apps provide no protection against, and may actively contribute to, incorrect or inappropriate dose recommendations that put current users at risk of both catastrophic overdose and more

  19. Alternative Assessment Approaches for Online Learning Environments in Higher Education.

    ERIC Educational Resources Information Center

    Reeves, Thomas C.

    2000-01-01

    Describes the need and prospects for alternative assessment approaches in online learning environments in higher education. Explains the difference between assessment and evaluation and discusses three approaches to integrating alternative assessment approaches into online learning environments: cognitive assessment, performance assessment, and…

  20. JADA: a graphical user interface for comprehensive internal dose assessment in nuclear medicine.

    PubMed

    Grimes, Joshua; Uribe, Carlos; Celler, Anna

    2013-07-01

    The main objective of this work was to design a comprehensive dosimetry package that would keep all aspects of internal dose calculation within the framework of a single software environment and that would be applicable for a variety of dose calculation approaches. Our MATLAB-based graphical user interface (GUI) can be used for processing data obtained using pure planar, pure SPECT, or hybrid planar/SPECT imaging. Time-activity data for source regions are obtained using a set of tools that allow the user to reconstruct SPECT images, load images, coregister a series of planar images, and to perform two-dimensional and three-dimensional image segmentation. Curve fits are applied to the acquired time-activity data to construct time-activity curves, which are then integrated to obtain time-integrated activity coefficients. Subsequently, dose estimates are made using one of three methods. The organ level dose calculation subGUI calculates mean organ doses that are equivalent to dose assessment performed by OLINDA/EXM. Voxelized dose calculation options, which include the voxel S value approach and Monte Carlo simulation using the EGSnrc user code DOSXYZnrc, are available within the process 3D image data subGUI. The developed internal dosimetry software package provides an assortment of tools for every step in the dose calculation process, eliminating the need for manual data transfer between programs. This saves times and minimizes user errors, while offering a versatility that can be used to efficiently perform patient-specific internal dose calculations in a variety of clinical situations.

  1. Guidance on internal dose assessments from monitoring data (project IDEAS).

    PubMed

    Doerfel, H; Andrasi, A; Bailey, M; Berkovski, V; Castellani, C M; Hurtgen, C; Jourdain, J R; LeGuen, B

    2003-01-01

    Several international inter-comparison exercises on intake and internal dose assessments from monitoring data led to the conclusion that the results calculated by different participants varied significantly, mainly due to the broad variety of methods and assumptions applied in the assessment procedure. Based on these experiences, the need of harmonisation of the procedures has been formulated as an EU research project under the 5th Framework Programme, with the aim of developing general guidelines for standardising assessments of intakes and internal doses. In the IDEAS project, eight institutions from seven European countries are participating, also using inputs from internal dosimetry professionals from across Europe to ensure broad consensus in the outcome of the project. To ensure that the guidelines are applicable to a wide range of practical situations, the first step will be to compile a database on well documented cases of internal contamination. In parallel, an improved version of existing software will be developed and distributed to the partners for further use. Many cases from the database will be evaluated independently by more partners using the same software and the results will be discussed and the draft guidelines prepared. The guidelines will then be revised and refined on the basis of the experiences and discussions of two workshops, and an intercomparison exercise organised in the frame of the project which will be open to all internal dosimetry professionals.

  2. Dealing with uncertainty in the assessment of human exposure to radioactivity in food and the environment.

    PubMed

    Ould-Dada, Zitouni

    2006-12-01

    This paper presents an overview of the approach used to assess radiation dose and risk to members of the public from radioactivity in food and the environment. It describes uncertainties in the process and suggests ways of dealing with them to improve the risk assessment process. It also explains how uncertainty in the assessed dose/risk can be communicated to non-expert audiences such as members of the public. The issues covered in this paper apply to risk assessment of any contaminant and not only radioactivity.

  3. Europa Surface Radiation Environment for Lander Assessment

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Sturner, Steven J.

    2006-01-01

    The Jovian magnetospheric particle environment at Europa's surface is critical to assessment of landed astrobiological experiments in three respects: (1) the landing site must be chosen for the best prospects for detectable organic or inorganic signs of Life, e.g. regions of freshly emergent flows from the subsurface; (2) lander systems must reach the surface through the Jovian magnetospheric environment and operate long enough on the surface to return useful data; (3) lander instrumentation must be capable of detecting signs of life in the context of the local environmental radiation and associated chemistry. The Galileo, Voyager, and Pioneer missions have provided a wealth of data on energetic particle intensities throughout the Jovian magnetosphere including from many flybys of Europa. cumulative radiation dosages for spacecraft enroute to Europa can be well characterized, but knowledge of the surface radiation environment is very limited. Energetic electrons should primarily impact the trailing hemisphere with decreasing intensity towards the center of the leading hemisphere and are the most significant radiation component down to meter depths in the surface regolith due to secondary interactions. Observed surface distribution for sulfates is suggestive of electron irradiation but may have alternative interpretations. Having much-larger magnetic gyroradii than electrons, energetic protons and heavier ions irradiate more of the global surface. The particular orientations of electron, proton, and ion gyromotion would project into corresponding directional (e.g., east-west) anisotropies of particle flu into the surface. Particular topographic features at the landing site may therefore offer shielding from part of the incident radiation.

  4. Europa Surface Radiation Environment for Lander Assessment

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Sturner, Steven J.

    2006-01-01

    The Jovian magnetospheric particle environment at Europa's surface is critical to assessment of landed astrobiological experiments in three respects: (1) the landing site must be chosen for the best prospects for detectable organic or inorganic signs of Life, e.g. regions of freshly emergent flows from the subsurface; (2) lander systems must reach the surface through the Jovian magnetospheric environment and operate long enough on the surface to return useful data; (3) lander instrumentation must be capable of detecting signs of life in the context of the local environmental radiation and associated chemistry. The Galileo, Voyager, and Pioneer missions have provided a wealth of data on energetic particle intensities throughout the Jovian magnetosphere including from many flybys of Europa. cumulative radiation dosages for spacecraft enroute to Europa can be well characterized, but knowledge of the surface radiation environment is very limited. Energetic electrons should primarily impact the trailing hemisphere with decreasing intensity towards the center of the leading hemisphere and are the most significant radiation component down to meter depths in the surface regolith due to secondary interactions. Observed surface distribution for sulfates is suggestive of electron irradiation but may have alternative interpretations. Having much-larger magnetic gyroradii than electrons, energetic protons and heavier ions irradiate more of the global surface. The particular orientations of electron, proton, and ion gyromotion would project into corresponding directional (e.g., east-west) anisotropies of particle flu into the surface. Particular topographic features at the landing site may therefore offer shielding from part of the incident radiation.

  5. [Work environment assessment at a medical school].

    PubMed

    Sánchez D, Ignacio; Airola G, Gregorio; Cayazzo A, Tatiana; Pedrals G, Nuria; Rodríguez M, Magdalena; Villarroel D, Luis

    2009-11-01

    The work environment of an organization has to do with a set of permanent qualities that are experienced by its members. To assess the work environment perception of faculty members of a Medical School in two different periods (2005 and 2007). A standardized survey was applied to faculty members and Department chairs of the academic units of our Medical School. The survey used the Likert scale from 1 to 5 and included 59 items, distributed in 8 factors. Additionally, there were two groups of statements, indicating the priorities for the School and for the academic departments. In the study performed in year 2005, the survey was answered by a total of 399 faculty members (68%) and in year 2007, it was answered by 408 members (68%). The global climate perceptions were 66% and 68% in 2005 and 2007, respectively (ns). Among the dimensions evaluated, communications (p =0,62) and physical conditions (p =0,008) improved in the two years period. The applied instrument was stable and useful to knowing the requirements of the faculty members and for improving the organizational climate.

  6. Assessment Environment for Complex Systems Software Guide

    NASA Technical Reports Server (NTRS)

    2013-01-01

    This Software Guide (SG) describes the software developed to test the Assessment Environment for Complex Systems (AECS) by the West Virginia High Technology Consortium (WVHTC) Foundation's Mission Systems Group (MSG) for the National Aeronautics and Space Administration (NASA) Aeronautics Research Mission Directorate (ARMD). This software is referred to as the AECS Test Project throughout the remainder of this document. AECS provides a framework for developing, simulating, testing, and analyzing modern avionics systems within an Integrated Modular Avionics (IMA) architecture. The purpose of the AECS Test Project is twofold. First, it provides a means to test the AECS hardware and system developed by MSG. Second, it provides an example project upon which future AECS research may be based. This Software Guide fully describes building, installing, and executing the AECS Test Project as well as its architecture and design. The design of the AECS hardware is described in the AECS Hardware Guide. Instructions on how to configure, build and use the AECS are described in the User's Guide. Sample AECS software, developed by the WVHTC Foundation, is presented in the AECS Software Guide. The AECS Hardware Guide, AECS User's Guide, and AECS Software Guide are authored by MSG. The requirements set forth for AECS are presented in the Statement of Work for the Assessment Environment for Complex Systems authored by NASA Dryden Flight Research Center (DFRC). The intended audience for this document includes software engineers, hardware engineers, project managers, and quality assurance personnel from WVHTC Foundation (the suppliers of the software), NASA (the customer), and future researchers (users of the software). Readers are assumed to have general knowledge in the field of real-time, embedded computer software development.

  7. Assessing the built environment using omnidirectional imagery.

    PubMed

    Wilson, Jeffrey S; Kelly, Cheryl M; Schootman, Mario; Baker, Elizabeth A; Banerjee, Aniruddha; Clennin, Morgan; Miller, Douglas K

    2012-02-01

    Observational audits commonly are used in public health research to collect data on built environment characteristics that affect health-related behaviors and outcomes, including physical activity and weight status. However, implementing in-person field audits can be expensive if observations are needed over large or geographically dispersed areas or at multiple points in time. A reliable and more efficient method for observational audits could facilitate extendibility (i.e., expanded geographic and temporal scope) and lead to more standardized assessment that strengthens the ability to compare results across different regions and studies. The purpose of the current study was to evaluate the degree of agreement between field audits and audits derived from interpretation of three types of omnidirectional imagery. Street segments from St. Louis MO and Indianapolis IN were stratified geographically to ensure representation of neighborhoods with different socioeconomic characteristics in both cities. Audits were conducted in 2008 and 2009 using four methods: field audits, and interpretation of archived imagery, new imagery, and Google Street View™ imagery. Agreement between field audits and image-based audits was assessed using observed agreement and the prevalence-adjusted bias-adjusted kappa statistic (PABAK). Data analysis was conducted in 2010. When measuring the agreement between field audits and audits from the different sources of imagery, the mean PABAK statistic for all items on the instrument was 0.78 (archived); 0.80 (new); and 0.81 (Street View imagery), indicating substantial to nearly perfect agreement among methods. It was determined that image-based audits represent a reliable method that can be used in place of field audits to measure several key characteristics of the built environment important to public health research. Copyright © 2012 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  8. Mixed species radioiodine air sampling readout and dose assessment system

    DOEpatents

    Distenfeld, Carl H.; Klemish, Jr., Joseph R.

    1978-01-01

    This invention provides a simple, reliable, inexpensive and portable means and method for determining the thyroid dose rate of mixed airborne species of solid and gaseous radioiodine without requiring highly skilled personnel, such as health physicists or electronics technicians. To this end, this invention provides a means and method for sampling a gas from a source of a mixed species of solid and gaseous radioiodine for collection of the mixed species and readout and assessment of the emissions therefrom by cylindrically, concentrically and annularly molding the respective species around a cylindrical passage for receiving a conventional probe-type Geiger-Mueller radiation detector.

  9. Classification of thermal environments for comfort assessment.

    PubMed

    Lenzuni, Paolo; Freda, Daniela; Del Gaudio, Michele

    2009-06-01

    According to ISO 7730:2005, classification is a mandatory precondition for thermal comfort assessment since the appropriate criterion depends on which category the specific work situation (SWS) investigated belongs to. Unfortunately, while the standard does include three different comfort criteria, it does not indicate how the appropriate criterion should be selected. This paper presents a classification scheme that allows thermal comfort assessment to be reliably performed in any environment. The model is based on an algorithm that calculates a score by means of a weighted product of three quantities, each one taking care of a specific, highly relevant element: the subject's thermal sensitivity, the accuracy required for carrying out the task and the practicality of thermal control. The scheme's simple modular structure can easily accommodate both changes and additions, should other hypothetical elements be identified to be as relevant to the classification scheme. The model presented allows a modulation of comfort levels across different social groups. It is so possible to provide extra care for children, elderly, pregnant women, disabled and other 'weak' categories, as required by ISO/TS 14415:2005, by setting the highest comfort level. Finally, it also widens the options for simultaneously establishing comfort conditions for different individuals performing different tasks in the same area and clarifies whose comfort should be pursued with the highest priority.

  10. Methodology for estimating radiation dose rates to freshwater biota exposed to radionuclides in the environment

    SciTech Connect

    Blaylock, B.G.; Frank, M.L.; O`Neal, B.R.

    1993-08-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy`s (DOE`s) recommended dose rate limit of 0.4 mGy h{sup {minus}1} (1 rad d{sup {minus}1}). A dose rate no greater than 0.4 mGy h{sup {minus}1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE`s recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0. 1 mGy h{sup {minus}1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be conducted.

  11. Evaluation of the Emergency Response Dose Assessment System(ERDAS)

    NASA Technical Reports Server (NTRS)

    Evans, Randolph J.; Lambert, Winifred C.; Manobianco, John T.; Taylor, Gregory E.; Wheeler, Mark M.; Yersavich, Ann M.

    1996-01-01

    The emergency response dose assessment system (ERDAS) is a protype software and hardware system configured to produce routine mesoscale meteorological forecasts and enhanced dispersion estimates on an operational basis for the Kennedy Space Center (KSC)/Cape Canaveral Air Station (CCAS) region. ERDAS provides emergency response guidance to operations at KSC/CCAS in the case of an accidental hazardous material release or an aborted vehicle launch. This report describes the evaluation of ERDAS including: evaluation of sea breeze predictions, comparison of launch plume location and concentration predictions, case study of a toxic release, evaluation of model sensitivity to varying input parameters, evaluation of the user interface, assessment of ERDA's operational capabilities, and a comparison of ERDAS models to the ocean breeze dry gultch diffusion model.

  12. Homeopathic Doses of Gelsemium sempervirens Improve the Behavior of Mice in Response to Novel Environments

    PubMed Central

    Bellavite, Paolo; Magnani, Paolo; Zanolin, Elisabetta; Conforti, Anita

    2011-01-01

    Gelsemium sempervirens is used in homeopathy for treating patients with anxiety related symptoms, however there have been few experimental studies evaluating its pharmacological activity. We have investigated the effects of homeopathic doses of G. sempervirens on mice, using validated behavioral models. Centesimal (CH) dilutions/dynamizations of G. sempervirens, the reference drug diazepam (1 mg/kg body weight) or a placebo (solvent vehicle) were intraperitoneally delivered to groups of mice of CD1 strain during 8 days, then the effects were assessed by the Light-Dark (LD) choice test and by the Open-Field (OF) exploration test, in a fully blind manner. In the LD test, the mean time spent in the illuminated area by control and placebo-treated animals was 15.98%, for mice treated with diazepam it increased to 19.91% (P = .047), while with G. sempervirens 5 CH it was 18.11% (P = .341, non-significant). The number of transitions between the two compartments increased with diazepam from 6.19 to 9.64 (P < .001) but not with G. Sempervirens. In the OF test, G. sempervirens 5 CH significantly increased the time spent and the distance traveled in the central zone (P = .009 and P = .003, resp.), while diazepam had no effect on these OF test parameters. In a subsequent series of experiments, G. sempervirens 7 and 30 CH also significantly improved the behavioral responses of mice in the OF test (P < .01 for all tested variables). Neither dilutions of G. sempervirens affected the total distance traveled, indicating that the behavioral effect was not due to unspecific changes in locomotor activity. In conclusion, homeopathic doses of G. sempervirens influence the emotional responses of mice to novel environments, suggesting an improvement in exploratory behavior and a diminution of thigmotaxis or neophobia. PMID:19752165

  13. Assessing the effect of electron density in photon dose calculations

    SciTech Connect

    Seco, J.; Evans, P. M.

    2006-02-15

    Photon dose calculation algorithms (such as the pencil beam and collapsed cone, CC) model the attenuation of a primary photon beam in media other than water, by using pathlength scaling based on the relative mass density of the media to water. In this study, we assess if differences in the electron density between the water and media, with different atomic composition, can influence the accuracy of conventional photon dose calculations algorithms. A comparison is performed between an electron-density scaling method and the standard mass-density scaling method for (i) tissues present in the human body (such as bone, muscle, etc.), and for (ii) water-equivalent plastics, used in radiotherapy dosimetry and quality assurance. We demonstrate that the important material property that should be taken into account by photon dose algorithms is the electron density, and not the mass density. The mass-density scaling method is shown to overestimate, relative to electron-density predictions, the primary photon fluence for tissues in the human body and water-equivalent plastics, where 6%-7% and 10% differences were observed respectively for bone and air. However, in the case of patients, differences are expected to be smaller due to the large complexity of a treatment plan and of the patient anatomy and atomic composition and of the smaller thickness of bone/air that incident photon beams of a treatment plan may have to traverse. Differences have also been observed for conventional dose algorithms, such as CC, where an overestimate of the lung dose occurs, when irradiating lung tumors. The incorrect lung dose can be attributed to the incorrect modeling of the photon beam attenuation through the rib cage (thickness of 2-3 cm in bone upstream of the lung tumor) and through the lung and the oversimplified modeling of electron transport in convolution algorithms. In the present study, the overestimation of the primary photon fluence, using the mass-density scaling method, was shown

  14. Technical Basis for Expedited Processing of Radiation Dose Assessments for NTPR Hiroshima and Nagasaki Participants

    DTIC Science & Technology

    2015-11-01

    expedited processing of Radiation Dose Assessments (RDAs) for Hiroshima and Nagasaki (H&N) veterans in the Nuclear Test Personnel Review (NTPR) Program...Expedited processing of Nuclear Test Personnel Review program radiation dose assessments (RDAs) is an option for certain claims from the Department...Agency), 2015a. Expedited Processing of Radiation Dose Assessments for Atmospheric Nuclear Weapons Testing Veterans, NTPR Standard Operating

  15. [The methodology development of the calculating and empirical internal dose assessments at far post Chernobyl period].

    PubMed

    Vlasova, N G; Zhuchenko, Iu M; Chunikhin, L A

    2009-01-01

    The comparison analysis of internal dose assessment had been conducted by different calculated methods. The results of the WBC measurements were used as a criteria of internal dose assessment. It was shown that the methodology of the internal dose assessment intended uncertainties reducing of the received results. It is realized by means of the modern WBC modeling.

  16. Variation of indoor radon concentration and ambient dose equivalent rate in different outdoor and indoor environments.

    PubMed

    Stojanovska, Zdenka; Boev, Blazo; Zunic, Zora S; Ivanova, Kremena; Ristova, Mimoza; Tsenova, Martina; Ajka, Sorsa; Janevik, Emilija; Taleski, Vaso; Bossew, Peter

    2016-05-01

    Subject of this study is an investigation of the variations of indoor radon concentration and ambient dose equivalent rate in outdoor and indoor environments of 40 dwellings, 31 elementary schools and five kindergartens. The buildings are located in three municipalities of two, geologically different, areas of the Republic of Macedonia. Indoor radon concentrations were measured by nuclear track detectors, deployed in the most occupied room of the building, between June 2013 and May 2014. During the deploying campaign, indoor and outdoor ambient dose equivalent rates were measured simultaneously at the same location. It appeared that the measured values varied from 22 to 990 Bq/m(3) for indoor radon concentrations, from 50 to 195 nSv/h for outdoor ambient dose equivalent rates, and from 38 to 184 nSv/h for indoor ambient dose equivalent rates. The geometric mean value of indoor to outdoor ambient dose equivalent rates was found to be 0.88, i.e. the outdoor ambient dose equivalent rates were on average higher than the indoor ambient dose equivalent rates. All measured can reasonably well be described by log-normal distributions. A detailed statistical analysis of factors which influence the measured quantities is reported.

  17. Methodology for Estimating Radiation Dose Rates to Freshwater Biota Exposed to Radionuclides in the Environment

    SciTech Connect

    Blaylock, B.G.

    1993-01-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy's (DOE's) recommended dose rate limit of 0.4 mGy h{sup -1} (1 rad d{sup -1}). A dose rate no greater than 0.4 mGy h{sup -1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE's recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). The literature identifies the developing eggs and young of some species of teleost fish as the most radiosensitive organisms. DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0.1 mGy h{sup -1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be

  18. Dose estimation derived from the exposure to radon, thoron and their progeny in the indoor environment

    PubMed Central

    Ramola, R. C.; Prasad, Mukesh; Kandari, Tushar; Pant, Preeti; Bossew, Peter; Mishra, Rosaline; Tokonami, S.

    2016-01-01

    The annual exposure to indoor radon, thoron and their progeny imparts a major contribution to inhalation doses received by the public. In this study, we report results of time integrated passive measurements of indoor radon, thoron and their progeny concentrations that were carried out in Garhwal Himalaya with the aim of investigating significant health risk to the dwellers in the region. The measurements were performed using recently developed LR-115 detector based techniques. The experimentally determined values of radon, thoron and their progeny concentrations were used to estimate total annual inhalation dose and annual effective doses. The equilibrium factors for radon and thoron were also determined from the observed data. The estimated value of total annual inhalation dose was found to be 1.8 ± 0.7 mSv/y. The estimated values of the annual effective dose were found to be 1.2 ± 0.5 mSv/y and 0.5 ± 0.3 mSv/y, respectively. The estimated values of radiation doses suggest no important health risk due to exposure of radon, thoron and progeny in the study area. The contribution of indoor thoron and its progeny to total inhalation dose ranges between 13–52% with mean value of 30%. Thus thoron cannot be neglected when assessing radiation doses. PMID:27499492

  19. Dose estimation derived from the exposure to radon, thoron and their progeny in the indoor environment

    NASA Astrophysics Data System (ADS)

    Ramola, R. C.; Prasad, Mukesh; Kandari, Tushar; Pant, Preeti; Bossew, Peter; Mishra, Rosaline; Tokonami, S.

    2016-08-01

    The annual exposure to indoor radon, thoron and their progeny imparts a major contribution to inhalation doses received by the public. In this study, we report results of time integrated passive measurements of indoor radon, thoron and their progeny concentrations that were carried out in Garhwal Himalaya with the aim of investigating significant health risk to the dwellers in the region. The measurements were performed using recently developed LR-115 detector based techniques. The experimentally determined values of radon, thoron and their progeny concentrations were used to estimate total annual inhalation dose and annual effective doses. The equilibrium factors for radon and thoron were also determined from the observed data. The estimated value of total annual inhalation dose was found to be 1.8 ± 0.7 mSv/y. The estimated values of the annual effective dose were found to be 1.2 ± 0.5 mSv/y and 0.5 ± 0.3 mSv/y, respectively. The estimated values of radiation doses suggest no important health risk due to exposure of radon, thoron and progeny in the study area. The contribution of indoor thoron and its progeny to total inhalation dose ranges between 13–52% with mean value of 30%. Thus thoron cannot be neglected when assessing radiation doses.

  20. Possible use of EPDM in radioactive waste disposal: Long term low dose rate and short term high dose rate irradiation in aquatic and atmospheric environment

    NASA Astrophysics Data System (ADS)

    Hacıoğlu, Fırat; Özdemir, Tonguç; Çavdar, Seda; Usanmaz, Ali

    2013-02-01

    In this study, changes in the properties of ethylene propylene diene terpolymer (EPDM) irradiated with different dose rates in ambient atmosphere and aqueous environment were investigated. Irradiations were carried out both with low dose and high dose rate irradiation sources. EPDM samples which were differentiated from each other by peroxide type and 5-ethylidene 2-norbornene (ENB) contents were used. Long term low dose rate irradiations were carried out for the duration of up to 2.5 years (total dose of 1178 kGy) in two different irradiation environments. Dose rates (both high and low), irradiation environments (in aquatic and open to atmosphere), and peroxide types (aliphatic or aromatic) were the parameters studied. Characterization of irradiated EPDM samples were performed by hardness, compression, tensile, dynamic mechanical analysis (DMA), TGA-FTIR, ATR-FTIR, XRD and SEM tests. It was observed that the irradiation in water environment led to a lower degree of degradation when compared to that of irradiation open to atmosphere for the same irradiation dose. In addition, irradiation environment, peroxide type and dose rate had effects on the extent of change in the properties of EPDM. It was observed that EPDM is relatively radiation resistant and a candidate polymer for usage in radioactive waste management.

  1. Dose related risk and effect assessment model (DREAM) -- A more realistic approach to risk assessment of offshore discharges

    SciTech Connect

    Johnsen, S.; Furuholt, E.

    1995-12-31

    Risk assessment of discharges from offshore oil and gas production to the marine environment features determination of potential environmental concentration (PEC) levels and no observed effect concentration (NOEC) levels. The PEC values are normally based on dilution of chemical components in the actual discharge source in the recipient, while the NOEC values are determined by applying a safety factor to acute toxic effects from laboratory tests. The DREAM concept focuses on realistic exposure doses as function of contact time and dilution, rather than fixed exposure concentrations of chemicals in long time exposure regimes. In its present state, the DREAM model is based on a number of assumptions with respect to the link between real life exposure doses and effects observed in laboratory tests. A research project has recently been initiated to develop the concept further, with special focus on chronic effects of different chemical compounds on the marine ecosystem. One of the questions that will be addressed is the link between exposure time, dose, concentration and effect. Validation of the safety factors applied for transforming acute toxic data into NOEC values will also be included. The DREAM model has been used by Statoil for risk assessment of discharges from new and existing offshore oil and gas production fields, and has been found to give a much more realistic results than conventional risk assessment tools. The presentation outlines the background for the DREAM approach, describes the model in its present state, discusses further developments and applications, and shows a number of examples on the performance of DREAM.

  2. Interactive Rapid Dose Assessment Model (IRDAM): reactor-accident assessment methods. Vol. 2

    SciTech Connect

    Poeton, R.W.; Moeller, M.P.; Laughlin, G.J.; Desrosiers, A.E.

    1983-05-01

    As part of the continuing emphasis on emergency preparedness, the US Nuclear Regulatory Commission (NRC) sponsored the development of a rapid dose assessment system by Pacific Northwest Laboratory (PNL). This system, the Interactive Rapid Dose Assessment Model (IRDAM) is a micro-computer based program for rapidly assessing the radiological impact of accidents at nuclear power plants. This document describes the technical bases for IRDAM including methods, models and assumptions used in calculations. IRDAM calculates whole body (5-cm depth) and infant thyroid doses at six fixed downwind distances between 500 and 20,000 meters. Radionuclides considered primarily consist of noble gases and radioiodines. In order to provide a rapid assessment capability consistent with the capacity of the Osborne-1 computer, certain simplifying approximations and assumptions are made. These are described, along with default values (assumptions used in the absence of specific input) in the text of this document. Two companion volumes to this one provide additional information on IRDAM. The user's Guide (NUREG/CR-3012, Volume 1) describes the setup and operation of equipment necessary to run IRDAM. Scenarios for Comparing Dose Assessment Models (NUREG/CR-3012, Volume 3) provides the results of calculations made by IRDAM and other models for specific accident scenarios.

  3. Dose assessment to workers in a dicalcium phosphate production plant.

    PubMed

    Mulas, D; Garcia-Orellana, J; Casacuberta, N; Hierro, A; Moreno, V; Masqué, P

    2016-12-01

    The production of dicalcium phosphate (DCP) uses phosphate rock (PR) as a raw material. Sedimentary phosphate rocks are enriched with relevant concentrations of natural radionuclides from the (238)U decay chain (around 10(3) Bq·kg(-1)), leading to the need of controlling potential exposures to radiation of workers and members of the public in accordance with IAEA safety standards. Indeed, phosphate industries are classified as Naturally Occurring Radioactive Material (NORM) industries. Thus, the aim of this work is to assess the radiological risk of the workers in a DCP production plant located in the Iberian Peninsula (South-West Europe), which digests PR with hydrochloric acid. In the present study (238)U, (230)Th, (222)Rn, (210)Pb and (210)Po concentrations in aerosols (indoor and outdoor areas) are reported. Aerosols showed concentrations between 0.42-92 mBq·m(-3) for (238)U, 0.24-33 mBq·m(-3) for (230)Th, 0.67-147 mBq·m(-3) for (210)Pb and 0.09-34 mBq·m(-3) for (210)Po. Long-term exposure (four months) of passive (222)Rn detectors provided concentrations that ranged from detection limit (< DL) to 121 Bq·m(-3) in outdoor areas and from < DL to 211 Bq·m(-3) in indoor areas, similar to concentrations obtained from short-term measurements with active detectors from < DL to 117 Bq·m(-3) in outdoor areas and from < DL to 318 Bq·m(-3) in indoor places. (226)Ra accumulation in ebonite and pipe scales were the most important contributions to the ambient dose equivalent H*(10), resulting in 0.07 (background)-27 μSv·h(-1) with a median value of 1.1 μSv·h(-1). Average (222)Rn air concentrations were lower than the 300 Bq·m(-3) limit and therefore, according to European Directive 2013/59/EURATOM, (222)Rn concentration is excluded from the worker operational annual effective dose. Thus, considering the inhalation of aerosols and the external dose sources, the total effective dose determined for plant operators was 0.37 mSv·y(-1). Copyright © 2016 Elsevier

  4. Effect of Radiocesium Transfer on Ambient Dose Rate in Forest Environment

    NASA Astrophysics Data System (ADS)

    Kato, Hiroaki; Onda, Yuichi; Loffredo, Nicolas; Hisadome, Keigo; Kawamori, Ayumi

    2014-05-01

    We investigated the transfer of canopy-intercepted radiocesium to the forest floor following the Fukushima Daiichi nuclear power plant accident. The cesium-137 (Cs-137) contents of throughfall, stemflow, and litterfall were monitored in two coniferous stands (plantation of Japanese cedar) and a deciduous broad-leaved forest stand (beech with red pine). We also measured an ambient dose rate at different height in the forest by using a survey meter (TCS-172B, Hitachi-Aloka Medical, LTD.) and a portable Ge gamma-ray detector (Detective-DX-100T, Ortec, Ametek, Inc.). In decreasing order of total Cs-137 deposition from the canopy to forest floor were the mature cedar stand, the young cedar stand, and the broad-leaved forest. The ambient dose rate in forest exhibited height dependency and its vertical distribution varied by forest type and stand age. The ambient dose rate showed an exponential decrease with time for all the forest sites, however the decreasing trend differed depending on the height of dose measurement and forest type. The ambient dose rates at the canopy (approx. 10 m-) decreased earlier than physical attenuation of radiocesium, whereas those at the forest floor varied among three forest stands. These data suggested that an ambient dose rate in forest environment can be variable in spatially and temporally reflecting the transfer of radiocesium from canopy to forest floor.

  5. Measurement of alpha radioactivity and dose assessment in common food crops with SSNTD.

    PubMed

    Ghosh, Dipak; Deb, Argha; Sengupta, Rosalima; Bera, Sukumar; Haldar, Subrata; Maitii, Sunil

    2011-01-01

    Radioactivity is present everywhere in the environment including soil, from where it transfers to vegetation and plants. These vegetations when taken as food result in transfer of the radioactivity to human beings which may cause health hazards. Thus information about the presence of radioactivity in vegetation, plants and soil is highly desirable. In this context, measurements of alpha radioactivity present in soil as well as in some of the staple food crops which form the main components of the composite Indian diet are presented in this study. Assessment of effective dose rate has also been done. The total alpha activity in soil has been found within 100-700 Bq kg(-1) and in food within 10-200 Bq kg(-1). The annual effective dose rate in food crops has been estimated in the range of 0.8-300 ì S v.

  6. Assessment of Neptunium, Americium, and Curium in the Savannah River Site Environment

    SciTech Connect

    Carlton, W.H.

    1997-12-17

    A series of documents has been published in which the impact of various radionuclides released to the environment by Savannah River Site (SRS) operations has been assessed. The quantity released, the disposition of the radionuclides in the environment, and the dose to offsite individuals has been presented for activation products, carbon cesium, iodine, plutonium, selected fission products, strontium, technetium, tritium, uranium, and the noble gases. An assessment of the impact of nonradioactive mercury also has been published.This document assesses the impact of radioactive transuranics released from SRS facilities since the first reactor became operational late in 1953. The isotopes reported here are 239Np, 241Am, and 244Cm.

  7. Diffuse and fugitive emission dose assessment on the Hanford Site

    SciTech Connect

    Davis, W.E.; Schmidt, J.W.; Gleckler, B.P.; Rhoads, K.

    1995-01-01

    On February 3, 1993, the US Department of Energy, Richland Operations Office (RL), received a Compliance Order and Information Request from the Director of the Air and Toxics Division of the US Environmental Protection Agency (EPA), Region 10. The Compliance Order requires RL to (1) evaluate all radionuclide emission points at the Hanford Site to determine which are subject to continuous emission measurement requirements in 40 Code of Federal Regulations (CFR) 61, Subpart H, and (2) continuously measure radionuclide emissions in accordance with 40 CFR 61.93. The Information Request requires RL to provide a written Compliance Plan to meet the requirements of the Compliance Order. The RL Compliance Plan included as one of its milestones the requirement to develop a Federal Facility Compliance Agreement (FFCA). An FFCA was negotiated between RL and the EPA, Region 10, and was entered into on February 7, 1994. One of the milestones was to provide EPA, Region 10, with a copy of the Federal Clean Air Act Title V operating air permit application and Air Emission Inventory (AEI) concurrent with its submission to the Washington State Department of Ecology. The AEI will include an assessment of the diffuse and fugitive emissions from the Hanford Site. This assessment does not identify any diffuse or fugitive emission source that would cause an effective dose equivalent greater than 0.1 mrem/yr.

  8. Assessment of dose during an SGTR. [Steam Generator Tube Rupture (SGTR)

    SciTech Connect

    Adams, J.P.

    1993-01-01

    The Nuclear Regulatory Commission requires utilities to determine the response of a pressurized water reactor to a steam generator tube rupture (SGTR) as part of the safety analysis for the plant. The SGTR analysis includes assumptions regarding the iodine concentration in the reactor coolant system (RCS) due to iodine spikes, primary flashing and bypass fractions, and iodine partitioning in the secondary coolant system (SCS). Experimental and analytical investigations have recently been completed wherein these assumptions were tested to determine whether and to what degree they were conservative (that is, whether they result in a calculated iodine source term/dose that is at least as large or larger than that expected during an actual event). The current study has the objective to assess the overall effects of the results of these investigations on the calculated iodine dose to the environment during an SGTR. To assist in this study, a computer program, DOSE, was written. This program uses a simple, non-mechanistic model to calculate the iodine source term to the environment during an SGTR as a function of water mass inventories and flow rates and iodine concentrations in the RCS and SCS. The principal conclusion of this study is that the iodine concentration in the RCS is the dominant parameter, due to the dominance of primary flashing on the iodine source term.

  9. Assessing Spatial Cognition in Stereoscopic Environments

    NASA Astrophysics Data System (ADS)

    Price, Aaron; Lee, H.

    2008-05-01

    Nineteen middle-school aged students visiting a planetarium were presented with three visuospatial tasks in both 2D (paper) and stereoscopic environments. The students' performance on tasks was evaluated in order to determine the impact of stereoscopic presentation upon accuracy and task completion time. Results show that accuracy did not differ between the two representational environments while completion time was greater for the stereoscopic environment. Post task interviews show that spatial and temporal discontiguity increased the cognitive load. Additionally, the interviews showed that students continued to visualize in two dimensions while using the stereoscopic representations.

  10. Technology Assessment and Roadmap for the Emergency Radiation Dose Assessment Program

    SciTech Connect

    Turteltaub, K W; Hartman-Siantar, C; Easterly, C; Blakely, W

    2005-10-03

    A Joint Interagency Working Group (JIWG) under the auspices of the Department of Homeland Security Office of Research and Development conducted a technology assessment of emergency radiological dose assessment capabilities as part of the overall need for rapid emergency medical response in the event of a radiological terrorist event in the United States. The goal of the evaluation is to identify gaps and recommend general research and development needs to better prepare the Country for mitigating the effects of such an event. Given the capabilities and roles for responding to a radiological event extend across many agencies, a consensus of gaps and suggested development plans was a major goal of this evaluation and road-mapping effort. The working group consisted of experts representing the Departments of Homeland Security, Health and Human Services (Centers for Disease Control and the National Institutes of Health), Food and Drug Administration, Department of Defense and the Department of Energy's National Laboratories (see appendix A for participants). The specific goals of this Technology Assessment and Roadmap were to: (1) Describe the general context for deployment of emergency radiation dose assessment tools following terrorist use of a radiological or nuclear device; (2) Assess current and emerging dose assessment technologies; and (3) Put forward a consensus high-level technology roadmap for interagency research and development in this area. This report provides a summary of the consensus of needs, gaps and recommendations for a research program in the area of radiation dosimetry for early response, followed by a summary of the technologies available and on the near-term horizon. We then present a roadmap for a research program to bring present and emerging near-term technologies to bear on the gaps in radiation dose assessment and triage. Finally we present detailed supporting discussion on the nature of the threats we considered, the status of technology

  11. PHYSIOLOCIGALLY BASED PHARMACOKINETIC (PBPK) MODELING AND MODE OF ACTION IN DOSE-RESPONSE ASSESSMENT

    EPA Science Inventory

    PHYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODELING AND MODE OF ACTION IN DOSE-RESPONSE ASSESSMENT. Barton HA. Experimental Toxicology Division, National Health and Environmental Effects Laboratory, ORD, U.S. EPA
    Dose-response analysis requires quantitatively linking infor...

  12. Imaging dose assessment for IGRT in particle beam therapy.

    PubMed

    Steiner, Elisabeth; Stock, Markus; Kostresevic, Boris; Ableitinger, Alexander; Jelen, Urszula; Prokesch, Hannah; Santiago, Alina; Trnková, Petra; Wolf, Adam; Wittig, Andrea; Lomax, Antony; Jäkel, Oliver; Baroni, Guido; Georg, Dietmar

    2013-12-01

    Image-guided advanced photon and particle beam treatments are promising options for improving lung treatments. Extensive use of imaging increases the overall patient dose. The aim of this study was to determine the imaging dose for different IGRT solutions used in photon and particle beam therapy. Measurements were performed in an Alderson phantom with TLDs. Clinically applied protocols for orthogonal planar kV imaging, stereoscopic imaging, CT scout views, fluoroscopy, CT, 4D-CT and CBCT were investigated at five ion beam centers and one conventional radiotherapy department. The overall imaging dose was determined for a patient undergoing a lung tumor irradiation with institute specific protocols. OAR doses depended on imaging modality and OAR position. Dose values were in the order of 1 mGy for planar and stereoscopic imaging and 10-50 mGy for volumetric imaging, except for one CBCT device leading to lower doses. The highest dose per exam (up to 150 mGy to the skin) was recorded for a 3-min fluoroscopy. Modalities like planar kV or stereoscopic imaging result in very low doses (≈ 1 mGy) to the patient. Imaging a moving target during irradiation, low-dose protocols and protocol optimization can reduce the imaging dose to the patient substantially. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  13. Radiological Dose Assessment - Nonuniform Skin Dose, Radioactive Skin Contamination, and Multiple Dosimetry

    SciTech Connect

    W. C. Inkret; M. E. Schillaci

    1999-03-01

    Radioactive skin contamination with {beta}- and {gamma}-emitting radionuclides may result in biologically significant absorbed doses to the skin. A specific exposure scenario of interest is a nonuniform skin dose delivered by {beta}- and {gamma}-emissions from radioactive skin contamination. The United States Department of Energy requires a formal evaluation and reporting of nonuniform skin doses. The United States Department of Energy also requires specific, formal procedures for evaluating the results from the placement or use of multiple dosimeters. Action levels relative to potential absorbed doses for the contamination survey instrumentation in use at Los Alamos and formal procedures for evaluating nonuniform skin doses and multiple dosimeters are developed and presented here.

  14. Dose assessment in environmental radiological protection: State of the art and perspectives.

    PubMed

    Stark, Karolina; Goméz-Ros, José M; Vives I Batlle, Jordi; Lindbo Hansen, Elisabeth; Beaugelin-Seiller, Karine; Kapustka, Lawrence A; Wood, Michael D; Bradshaw, Clare; Real, Almudena; McGuire, Corynne; Hinton, Thomas G

    2017-09-01

    Exposure to radiation is a potential hazard to humans and the environment. The Fukushima accident reminded the world of the importance of a reliable risk management system that incorporates the dose received from radiation exposures. The dose to humans from exposure to radiation can be quantified using a well-defined system; its environmental equivalent, however, is still in a developmental state. Additionally, the results of several papers published over the last decade have been criticized because of poor dosimetry. Therefore, a workshop on environmental dosimetry was organized by the STAR (Strategy for Allied Radioecology) Network of Excellence to review the state of the art in environmental dosimetry and prioritize areas of methodological and guidance development. Herein, we report the key findings from that international workshop, summarise parameters that affect the dose animals and plants receive when exposed to radiation, and identify further research needs. Current dosimetry practices for determining environmental protection are based on simple screening dose assessments using knowledge of fundamental radiation physics, source-target geometry relationships, the influence of organism shape and size, and knowledge of how radionuclide distributions in the body and in the soil profile alter dose. In screening model calculations that estimate whole-body dose to biota the shapes of organisms are simply represented as ellipsoids, while recently developed complex voxel phantom models allow organ-specific dose estimates. We identified several research and guidance development priorities for dosimetry. For external exposures, the uncertainty in dose estimates due to spatially heterogeneous distributions of radionuclide contamination is currently being evaluated. Guidance is needed on the level of dosimetry that is required when screening benchmarks are exceeded and how to report exposure in dose-effect studies, including quantification of uncertainties. Further

  15. Indoor aerosol modeling for assessment of exposure and respiratory tract deposited dose

    NASA Astrophysics Data System (ADS)

    Hussein, Tareq; Wierzbicka, Aneta; Löndahl, Jakob; Lazaridis, Mihalis; Hänninen, Otto

    2015-04-01

    Air pollution is one of the major environmental problems that influence people's health. Exposure to harmful particulate matter (PM) occurs both outdoors and indoors, but while people spend most of their time indoors, the indoor exposures tend to dominate. Moreover, higher PM concentrations due to indoor sources and tightness of indoor environments may substantially add to the outdoor originating exposures. Empirical and real-time assessment of human exposure is often impossible; therefore, indoor aerosol modeling (IAM) can be used as a superior method in exposure and health effects studies. This paper presents a simple approach in combining available aerosol-based modeling techniques to evaluate the real-time exposure and respiratory tract deposited dose based on particle size. Our simple approach consists of outdoor aerosol data base, IAM simulations, time-activity pattern data-base, physical-chemical properties of inhaled aerosols, and semi-empirical deposition fraction of aerosols in the respiratory tract. These modeling techniques allow the characterization of regional deposited dose in any metric: particle mass, particle number, and surface area. The first part of this presentation reviews recent advances in simple mass-balance based modeling methods that are needed in analyzing the health relevance of indoor exposures. The second part illustrates the use of IAM in the calculations of exposure and deposited dose. Contrary to previous methods, the approach presented is a real-time approach and it goes beyond the exposure assessment to provide the required information for the health risk assessment, which is the respiratory tract deposited dose. This simplified approach is foreseen to support epidemiological studies focusing on exposures originating from both indoor and outdoor sources.

  16. Evaluation of various approaches for assessing dose indicators and patient organ doses resulting from radiotherapy cone-beam CT

    SciTech Connect

    Rampado, Osvaldo Giglioli, Francesca Romana; Rossetti, Veronica; Ropolo, Roberto; Fiandra, Christian; Ragona, Riccardo

    2016-05-15

    Purpose: The aim of this study was to evaluate various approaches for assessing patient organ doses resulting from radiotherapy cone-beam CT (CBCT), by the use of thermoluminescent dosimeter (TLD) measurements in anthropomorphic phantoms, a Monte Carlo based dose calculation software, and different dose indicators as presently defined. Methods: Dose evaluations were performed on a CBCT Elekta XVI (Elekta, Crawley, UK) for different protocols and anatomical regions. The first part of the study focuses on using PCXMC software (PCXMC 2.0, STUK, Helsinki, Finland) for calculating organ doses, adapting the input parameters to simulate the exposure geometry, and beam dose distribution in an appropriate way. The calculated doses were compared to readouts of TLDs placed in an anthropomorphic Rando phantom. After this validation, the software was used for analyzing organ dose variability associated with patients’ differences in size and gender. At the same time, various dose indicators were evaluated: kerma area product (KAP), cumulative air-kerma at the isocenter (K{sub air}), cone-beam dose index, and central cumulative dose. The latter was evaluated in a single phantom and in a stack of three adjacent computed tomography dose index phantoms. Based on the different dose indicators, a set of coefficients was calculated to estimate organ doses for a range of patient morphologies, using their equivalent diameters. Results: Maximum organ doses were about 1 mGy for head and neck and 25 mGy for chest and pelvis protocols. The differences between PCXMC and TLDs doses were generally below 10% for organs within the field of view and approximately 15% for organs at the boundaries of the radiation beam. When considering patient size and gender variability, differences in organ doses up to 40% were observed especially in the pelvic region; for the organs in the thorax, the maximum differences ranged between 20% and 30%. Phantom dose indexes provided better correlation with organ

  17. An Evaluation of the Measurement of Perceived Classroom Assessment Environment

    ERIC Educational Resources Information Center

    Alkharusi, Hussain

    2015-01-01

    A classroom assessment environment is a classroom context experienced by students as the teacher determines assessment purposes, develops assessment tasks, defines assessment criteria and standards, provides feedback, and monitors outcomes (Brookhart, 1997). It is usually a group experience varying from class to class dependent upon the teacher's…

  18. Vaginal dose assessment in image-guided brachytherapy for cervical cancer: Can we really rely on dose-point evaluation?

    PubMed

    Limkin, Elaine Johanna; Dumas, Isabelle; Rivin Del Campo, Eleonor; Chargari, Cyrus; Maroun, Pierre; Annède, Pierre; Petit, Claire; Seisen, Thomas; Doyeux, Kaya; Tailleur, Anne; Martinetti, Florent; Lefkopoulos, Dimitri; Haie-Meder, Christine; Mazeron, Renaud

    2016-01-01

    Although dose-volume parameters in image-guided brachytherapy have become a standard, the use of posterior-inferior border of the pubic symphysis (PIBS) points has been recently proposed in the reporting of vaginal doses. The aim was to evaluate their pertinence. Nineteen patients who received image-guided brachytherapy after concurrent radiochemotherapy were included. Per treatment, CT scans were performed at Days 2 and 3, with reporting of the initial dwell positions and times. Doses delivered to the PIBS points were evaluated on each plan, considering that they were representative of one-third of the treatment. The movements of the applicator according to the PIBS point were analysed. Mean prescribed doses at PIBS -2, PIBS, PIBS +2 were, respectively, 2.23 ± 1.4, 6.39 ± 6.6, and 31.85 ± 36.06 Gy. Significant differences were observed between the 5 patients with vaginal involvement and the remaining 14 at the level of PIBS +2 and PIBS: +47.60 Gy and +7.46 Gy, respectively (p = 0.023 and 0.03). The variations between delivered and prescribed doses at PIBS points were not significant. However, at International commission on radiation units and measurements rectovaginal point, the delivered dose was decreased by 1.43 ± 2.49 Gy from the planned dose (p = 0.019). The delivered doses at the four points were strongly correlated with the prescribed doses with R(2) ranging from 0.93 to 0.95. The movements of the applicator in regard of the PIBS point assessed with the Digital Imaging and Communications in Medicine coordinates were insignificant. The doses evaluated at PIBS points are not impacted by intrafractional movements. PIBS and PIBS +2 dose points allow distinguishing the plans of patients with vaginal infiltration. Further studies are needed to correlate these parameters with vaginal morbidity. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  19. Creativity in an Assessment Driven Environment

    ERIC Educational Resources Information Center

    Coil, Carolyn

    2014-01-01

    Assessment can be defined as any method through which one gathers data or information about something. Assessing may incorporate measurement and testing, but it also includes evaluation and appreciation of creative products, processes, and performances. It encompasses finding out much more information than test results alone can give. Creative…

  20. Creativity in an Assessment Driven Environment

    ERIC Educational Resources Information Center

    Coil, Carolyn

    2014-01-01

    Assessment can be defined as any method through which one gathers data or information about something. Assessing may incorporate measurement and testing, but it also includes evaluation and appreciation of creative products, processes, and performances. It encompasses finding out much more information than test results alone can give. Creative…

  1. Observing and Assessing Infant Day Care Environment.

    ERIC Educational Resources Information Center

    Shapiro, Edna

    This paper describes data collection procedures for the part of the New York City Infant Day Care Study concerned with day care environment and caregiver-child interaction. This study is a 5-year, longitudinal investigation in which infants in group and family day care programs and infants reared at home are compared. Study data will be collected…

  2. Enabling Operations through the Assessment of the COIN Information Environment

    DTIC Science & Technology

    2011-08-18

    2011, Small Wars Foundation August 18, 2011 Enabling Operations through the Assessment of the COIN Information Environment by Brian J...models must be created to capture the information environment at that level. SMALL WARS JOURNAL smallwarsjournal.com Report Documentation Page Form...for assessing the information environment must be employed. Task Organization: The Analytics Cell While it is possible for a single individual to

  3. Pediatric cardiac-gated CT angiography: assessment of radiation dose.

    PubMed

    Hollingsworth, Caroline L; Yoshizumi, Terry T; Frush, Donald P; Chan, Frandics P; Toncheva, Greta; Nguyen, Giao; Lowry, Carolyn R; Hurwitz, Lynne M

    2007-07-01

    The purpose of our study was to determine a dose range for cardiac-gated CT angiography (CTA) in children. ECG-gated cardiac CTA simulating scanning of the heart was performed on an anthropomorphic phantom of a 5-year-old child on a 16-MDCT scanner using variable parameters (small field of view; 16 x 0.625 mm configuration; 0.5-second gantry cycle time; 0.275 pitch; 120 kVp at 110, 220, and 330 mA; and 80 kVp at 385 mA). Metal oxide semiconductor field effect transistor (MOSFET) technology measured 20 organ doses. Effective dose calculated using the dose-length product (DLP) was compared with effective dose determined from measured absorbed organ doses. Highest organ doses included breast (3.5-12.6 cGy), lung (3.3-12.1 cGy), and bone marrow (1.7-7.6 cGy). The 80 kVp/385 mA examination produced lower radiation doses to all organs than the 120 kVp/220 mA examination. MOSFET effective doses (+/- SD) were as follows: 110 mA: 7.4 mSv (+/- 0.6 mSv), 220 mA: 17.2 mSv (+/- 0.3 mSv), 330 mA: 25.7 mSv (+/- 0.3 mSv), 80 kVp/385 mA: 10.6 mSv (+/- 0.2 mSv). DLP effective doses for diagnostic runs were as follows: 110 mA: 8.7 mSv, 220 mA: 19 mSv, 330 mA: 28 mSv, 80 kVp/385 mA: 12 mSv. DLP effective doses exceeded MOSFET effective doses by 9.7-17.2%. Radiation doses for a 5-year-old during cardiac-gated CTA vary greatly depending on parameters. Organ doses can be high; the effective dose may reach 28.4 mSv. Further work, including determination of size-appropriate mA and image quality, is important before routine use of this technique in children.

  4. Standardizing Benchmark Dose Calculations to Improve Science-Based Decisions in Human Health Assessments

    PubMed Central

    Wignall, Jessica A.; Shapiro, Andrew J.; Wright, Fred A.; Woodruff, Tracey J.; Chiu, Weihsueh A.; Guyton, Kathryn Z.

    2014-01-01

    Background: Benchmark dose (BMD) modeling computes the dose associated with a prespecified response level. While offering advantages over traditional points of departure (PODs), such as no-observed-adverse-effect-levels (NOAELs), BMD methods have lacked consistency and transparency in application, interpretation, and reporting in human health assessments of chemicals. Objectives: We aimed to apply a standardized process for conducting BMD modeling to reduce inconsistencies in model fitting and selection. Methods: We evaluated 880 dose–response data sets for 352 environmental chemicals with existing human health assessments. We calculated benchmark doses and their lower limits [10% extra risk, or change in the mean equal to 1 SD (BMD/L10/1SD)] for each chemical in a standardized way with prespecified criteria for model fit acceptance. We identified study design features associated with acceptable model fits. Results: We derived values for 255 (72%) of the chemicals. Batch-calculated BMD/L10/1SD values were significantly and highly correlated (R2 of 0.95 and 0.83, respectively, n = 42) with PODs previously used in human health assessments, with values similar to reported NOAELs. Specifically, the median ratio of BMDs10/1SD:NOAELs was 1.96, and the median ratio of BMDLs10/1SD:NOAELs was 0.89. We also observed a significant trend of increasing model viability with increasing number of dose groups. Conclusions: BMD/L10/1SD values can be calculated in a standardized way for use in health assessments on a large number of chemicals and critical effects. This facilitates the exploration of health effects across multiple studies of a given chemical or, when chemicals need to be compared, providing greater transparency and efficiency than current approaches. Citation: Wignall JA, Shapiro AJ, Wright FA, Woodruff TJ, Chiu WA, Guyton KZ, Rusyn I. 2014. Standardizing benchmark dose calculations to improve science-based decisions in human health assessments. Environ Health

  5. Enhanced low dose rate sensitivity (ELDRS) of linear circuits in a space environment

    SciTech Connect

    Titus, J.L.; Emily, D.; Krieg, J.F.; Turflinger, T.; Pease, R.L.; Campbell, A.

    1999-12-01

    To investigate the ELDRS effect in a real space environment, an experiment was designed, launched, and placed in a highly elliptical orbit in November 1997. After its deployment, the electrical responses of several bipolar transistors and linear circuits have been and continue to be recorded once during every 12-hour orbit. System dosimeters are monitored to establish an average accumulated dose per orbit. With this information, the electrical parameter data are correlated with the dosimetry data to determine the total dose response of each device. This paper updates information on the ELDRS experiment through May 14, 1999. As of this date, the experiment has been in flight for a period of 18 months and has accumulated an approximate dose of 18 krd(Si). For comparison, devices, specifically linear circuits with the same date code, were irradiated using Co-60 sources, herein defined as ground-based tests. The ground-based tests are used to evaluate two hardness assurance tests, a room temperature irradiation at 10 mrd(Si)/s and an elevated temperature irradiation at 100 C and 10 rd(Si)/s and to evaluate the ELDRS response. To that end, irradiations were performed at room temperature, approximately 22 C, at fixed dose rates of 100, 1, and 0.01 rd(Si)/s and at elevated temperature, approximately 100 C, at a fixed dose rate of 10 rd(Si)/s. Currently, irradiations are being performed at room temperature at a fixed dose rate of 0.001 rd(Si)/s. Comparing the ground-based data to the flight data clearly demonstrates that enhanced parametric degradation has occurred in the flight parts. The two hardness assurance screens predicted ELDRS but the design margin for the elevated temperature test may not be adequate.

  6. EVALUATING QUANTITATIVE FORMULAS FOR DOSE-RESPONSE ASSESSMENT OF CHEMICAL MIXTURES

    EPA Science Inventory

    Risk assessment formulas are often distinguished from dose-response models by being rough but necessary. The evaluation of these rough formulas is described here, using the example of mixture risk assessment. Two conditions make the dose-response part of mixture risk assessment d...

  7. EVALUATING QUANTITATIVE FORMULAS FOR DOSE-RESPONSE ASSESSMENT OF CHEMICAL MIXTURES

    EPA Science Inventory

    Risk assessment formulas are often distinguished from dose-response models by being rough but necessary. The evaluation of these rough formulas is described here, using the example of mixture risk assessment. Two conditions make the dose-response part of mixture risk assessment d...

  8. Environmental dose assessment methods for normal operations at DOE nuclear sites

    SciTech Connect

    Strenge, D.L.; Kennedy, W.E. Jr.; Corley, J.P.

    1982-09-01

    Methods for assessing public exposure to radiation from normal operations at DOE facilities are reviewed in this report. The report includes a discussion of environmental doses to be calculated, a review of currently available environmental pathway models and a set of recommended models for use when environmental pathway modeling is necessary. Currently available models reviewed include those used by DOE contractors, the Environmental Protection Agency (EPA), the Nuclear Regulatory Commission (NRC), and other organizations involved in environmental assessments. General modeling areas considered for routine releases are atmospheric transport, airborne pathways, waterborne pathways, direct exposure to penetrating radiation, and internal dosimetry. The pathway models discussed in this report are applicable to long-term (annual) uniform releases to the environment: they do not apply to acute releases resulting from accidents or emergency situations.

  9. Physical activity and food environment assessments: implications for practice.

    PubMed

    Eyler, Amy A; Blanck, Heidi M; Gittelsohn, Joel; Karpyn, Allison; McKenzie, Thomas L; Partington, Susan; Slater, Sandy J; Winters, Meghan

    2015-05-01

    There is growing interest in the use of physical activity and nutrition environmental measures by both researchers and practitioners. Built environment assessment methods and tools range from simple to complex and encompass perceived, observed, and geographic data collection. Even though challenges in tool selection and use may exist for non-researchers, there are opportunities to incorporate these measures into practice. The aims of this paper are to (1) describe examples of built environment assessment methods and tools in the practice context; (2) present case studies that outline successful approaches for the use of built environment assessment tools and data among practitioners; and (3) make recommendations for both research and practice. As part of the Built Environment Assessment Training Think Tank meeting in July 2013, experts who work with community partners gathered to provide input on conceptualizing recommendations for collecting and analyzing built environment data in practice and research. The methods were summarized in terms of perceived environment measures, observational measures, and geographic measures for physical activity and food environment assessment. Challenges are outlined and case study examples of successful use of assessments in practice are described. Built environment assessment tools and measures are important outside the research setting. There is a need for improved collaboration between research and practice in forming partnerships for developing tools, collecting and analyzing data, and using the results to work toward positive environmental changes.

  10. Monitoring performance of the cameras under the high dose-rate gamma ray environments.

    PubMed

    Cho, Jai Wan; Choi, Young Soo; Jeong, Kyung Min

    2014-05-01

    CCD/CMOS cameras, loaded on a robot system, are generally used as the eye of the robot and monitoring unit. A major problem that arises when dealing with images provided by CCD/CMOS cameras under severe accident situations of a nuclear power plant is the presence of speckles owing to the high dose-rate gamma irradiation fields. To use a CCD/CMOS camera as a monitoring unit in a high radiation area, the legibility of the camera image in such intense gamma-radiation fields should therefore be defined. In this paper, the authors describe the monitoring index as a figure of merit of the camera's legibleness under a high dose-rate gamma ray irradiation environment. From a low dose-rate (10 Gy h) to a high dose-rate (200 Gy h) level, the legible performances of the cameras owing to the speckles are evaluated. The numbers of speckles generated by gamma ray irradiation in the camera image are calculated by an image processing technique. The legibility of the sensor indicator (thermo/hygrometer) owing to the number of speckles is also presented.

  11. Radiation dose assessment of exposure to depleted uranium.

    PubMed

    Li, Wei Bo; Gerstmann, Udo C; Höllriegl, Vera; Szymczak, Wilfried; Roth, Paul; Hoeschen, Christoph; Oeh, Uwe

    2009-07-01

    Depleted uranium (DU) is claimed to contribute to human health problems, known as the Gulf War Syndrome and the Balkan Syndrome. Quantitative radiation dose is required to estimate the health risk of DU materials. The influences of the solubility parameters in the human alimentary tract and the respiratory tract systems and the aerosol particles size on the radiation dose of DU materials were evaluated. The dose conversion factor of daily urinary excretion of DU is provided. The retention and excretion of DU in the human body after a contamination at a wound site were predicted. Dose coefficients of DU after ingestion and inhalation were calculated using the solubility parameters of the DU corrosion products in simulated gastric and simulated lung fluid, which were determined in the Helmholtz Zentrum München. (238)U is the main radiation dose contributor per 1 Bq of DU materials. The dose coefficients of DU materials were estimated to be 3.5 x 10(-8) and 2.1 x 10(-6) Sv Bq(-1) after ingestion and inhalation for members of the public. The ingestion dose coefficient of DU materials is about 75% of the natural uranium value. The inhalation dose coefficient of DU material is in between those for Type M and Type S according to the category for inhaled materials defined by the International Commission on Radiological Protection. Radiation dose possibly received from DU materials can directly be estimated by using the dose conversion factor provided in this study, if daily urinary excretion of DU is measured.

  12. Assessment of imidacloprid in Brassica environment.

    PubMed

    Kumar, R; Dikshit, A K

    2001-09-01

    Imidacloprid was applied as seed treatment (Gaucho 70 WS, 5 and 10 g ai kg(-1) seed) and foliar spray (Confidor 200 SL, 20 and 40 g ai ha(-1)) at 50% pod formation stage on mustard (Brassica campestris Linn.) to control mustard aphid, Lipaphis erysimi Kalt. It was detectable upto 82 and 96 days in plants after sowing from lower and higher doses of seed treatment. However, it dissipated faster and became nondetectable after 7 and 15 days of foliar treatments from lower and higher rates of application, respectively. The dissipation models yielded the rate constants of 0.0209 and 0.0230 and 0.0736 and 0.0779 day(-1) from seed and foliar treatment. The corresponding half-lives of 14.40 and 13.07 and 4.09 and 3.86 days were recorded. This suggested that the dissipation was independent of initial doses and followed a first order rate kinetics. The projected TMRC of imidacloprid from seed (0.136 and 0.225 mg person(-1) day(-1)) and foliar (0.069 and 0.1497 mg person(-1) day(-1)) treatments were found lower than the MPI (3.135 mg person(-1) day(-1)). At harvest mustard grains did not contain imidacloprid residues. The absence of imidacloprid in 0-10 and 10-20 cm soil layers indicated no leaching of insecticide. Therefore, imidacloprid treatments could be taken as safe for crop protection, consumption of leaves and environmental contamination point of view.

  13. KREAM: Korean Radiation Exposure Assessment Model for Aviation Route Dose

    NASA Astrophysics Data System (ADS)

    Hwang, J.; Dokgo, K.; Choi, E. J.; Kim, K. C.; Kim, H. P.; Cho, K. S. F.

    2014-12-01

    Since Korean Air has begun to use the polar route from Seoul/ICN airport to New York/JFK airport on August 2006, there are explosive needs for the estimation and prediction against cosmic radiation exposure for Korean aircrew and passengers in South Korea from public. To keep pace with those needs of public, Korean government made the law on safety standards and managements of cosmic radiation for the flight attendants and the pilots in 2013. And we have begun to develop our own Korean Radiation Exposure Assessment Model (KREAM) for aviation route dose since last year funded by Korea Meteorological Administration (KMA). GEANT4 model and NRLMSIS 00 model are used for calculation of the energetic particles' transport in the atmosphere and for obtaining the background atmospheric neutral densities depending on altitude. For prediction the radiation exposure in many routes depending on the various space weather effects, we constructed a database from pre-arranged simulations using all possible combinations of R, S, and G, which are the space weather effect scales provided by the National Oceanic and Atmospheric Administration (NOAA). To get the solar energetic particles' spectrum at the 100 km altitude which we set as a top of the atmospheric layers in the KREAM, we use ACE and GOES satellites' proton flux observations. We compare the results between KREAM and the other cosmic radiation estimation programs such as CARI-6M which is provided by the Federal Aviation Agency (FAA). We also validate KREAM's results by comparison with the measurement from Liulin-6K LET spectrometer onboard Korean commercial flights and Korean Air Force reconnaissance flights.

  14. The effects of a priming dose of alcohol and drinking environment on snack food intake.

    PubMed

    Rose, A K; Hardman, C A; Christiansen, P

    2015-12-01

    Alcohol consumption is a potential risk factor for being overweight. We aimed to investigate the effects of an alcohol priming dose and an alcohol-related environment on snacking behaviour. One hundred and fourteen social drinkers completed one of four experimental sessions either receiving a priming dose of alcohol (.6 g/kg) or soft drink in a bar-lab or a sterile lab. Participants provided ratings of appetite, snack urge, and alcohol urge before and after consuming their drinks. Participants completed an ad libitum snack taste test of savoury and sweet, healthy and unhealthy foods before completing the self-reports a final time. Appetite and snack urge increased more following alcohol consumption, and decreased to a lesser extent following the taste test relative to the soft drink. Total calories (including drink calories) consumed were significantly higher in the alcohol groups. There was a marginal effect of environment; those in the bar-lab consumed a higher proportion of unhealthy foods. These effects were more pronounced in those who were disinhibited. While alcohol may not increase food consumption per se, alcohol may acutely disrupt appetite signals, perhaps via processes of reward and inhibitory control, resulting in overall greater calorie intake. Individuals who are generally disinhibited may be more vulnerable to the effects of alcohol and drinking environments on eating behaviour.

  15. Toxicity from repeated doses of acetaminophen in children: Assessment of causality and dose in reported cases

    PubMed Central

    Heard, Kennon; Bui, Alison; Mlynarchek, Sara L; Green, Jody L.; Bond, G. Randall; Clark, Richard F.; Kozer, Eran; Koff, Raymond S.; Dart, Richard C.

    2012-01-01

    Background Liver injury has been reported in children treated with repeated doses of acetaminophen. The objective of this study is to identify and validate reports of liver injury or death in children younger than 6 years of age following repeated therapeutic doses of acetaminophen. Methods We reviewed United States (US) Poison Center data, peer-reviewed literature, US FDA Adverse event reports and US Manufacturer safety reports describing adverse effects following acetaminophen administration. Reports that described hepatic abnormalities (description of liver injury or abnormal laboratory testing) or death following administration to children younger than 6 years of age were included. The identified reports were double abstracted and then reviewed by an expert panel to determine if the hepatic injury was related to acetaminophen, and whether the dose of acetaminophen was therapeutic (≤75 mg/kg) or supra-therapeutic. Results Our search yielded 2531 reports of adverse events associated with acetaminophen use. From these cases, we identified 76 cases of hepatic injury and 26 deaths associated with repeated acetaminophen administration. There were 6 cases of hepatic abnormalities and no deaths associated with what our panel determined to be therapeutic doses. A large proportion of cases could not be fully evaluated due to incomplete case reporting. Conclusions While we identified numerous examples of liver injury and death following repeated doses of acetaminophen, all of the deaths and all but 6 cases of hepatic abnormalities involved doses greater than 75 mg/kg/day. This study suggests that the doses of less than 75 mg/kg/day of acetaminophen are safe for children younger than 6 years of age. PMID:22407198

  16. Toxicity from repeated doses of acetaminophen in children: assessment of causality and dose in reported cases.

    PubMed

    Heard, Kennon; Bui, Alison; Mlynarchek, Sara L; Green, Jody L; Bond, G Randall; Clark, Richard F; Kozer, Eran; Koff, Raymond S; Dart, Richard C

    2014-01-01

    Liver injury has been reported in children treated with repeated doses of acetaminophen. The objective of this study was to identify and validate reports of liver injury or death in children younger than 6 years who were administered repeated therapeutic doses of acetaminophen. We reviewed US Poison Center data, peer-reviewed literature, US Food and Drug Administration Adverse Event Reports, and US Manufacturer Safety Reports describing adverse effects after acetaminophen administration. Reports that described hepatic abnormalities (description of liver injury or abnormal laboratory testing) or death after acetaminophen administration to children younger than 6 years were included. The identified reports were double abstracted and then reviewed by an expert panel to determine if the hepatic injury was related to acetaminophen and whether the dose of acetaminophen was therapeutic (≤75 mg/kg) or supratherapeutic. Our search yielded 2531 reports of adverse events associated with acetaminophen use. From these cases, we identified 76 cases of hepatic injury and 26 deaths associated with repeated acetaminophen administration. There were 6 cases of hepatic abnormalities and no deaths associated with what our panel determined to be therapeutic doses. A large proportion of cases could not be fully evaluated due to incomplete case reporting. Although we identified numerous examples of liver injury and death after repeated doses of acetaminophen, all the deaths and all but 6 cases of hepatic abnormalities involved doses more than 75 mg/kg per day. This study suggests that the doses of less than 75 mg/kg per day of acetaminophen are safe for children younger than 6 years.

  17. Dose assessment of 2% chlorhexidine acetate for canine superficial pyoderma.

    PubMed

    Murayama, Nobuo; Terada, Yuri; Okuaki, Mio; Nagata, Masahiko

    2011-10-01

    The dose of 2% chlorhexidine acetate (2CA; Nolvasan(®) Surgical Scrub; Fort Dodge Animal Health, Fort Dodge, IA, USA) for canine superficial pyoderma was evaluated. The first trial compared three doses (group 1, 57 mL/m(2) body surface area; group 2, 29 mL/m(2) body surface area; and group 3, 19 mL/m(2) body surface area) in a randomized, double-blind, controlled fashion. Twenty-seven dogs with superficial pyoderma were treated with 2CA at the allocated doses every 2 days for 1 week. The owners and investigators subjectively evaluated the dogs, and investigators scored skin lesions, including erythema, papules/pustules, alopecia and scales, on a 0-4 scale. There were no significant differences in response between the treatment groups. The second trial established a practical dose-measuring method for 2CA. Sixty-eight owners were asked to apply 2CA on their palm in an amount corresponding to a Japanese ¥500 coin, 26.5 mm in diameter. This yielded an average dose of 0.90±0.40 mL. Mathematically, the doses used in groups 1, 2 and 3 can be represented as one coin per approximately one-, two- and three-hand-sized lesions, respectively. The results therefore suggest that owners instructed to apply one coin of the product per two-hand-sized areas of superficial pyoderma would use the range of doses evaluated in this trial.

  18. Radiation Dose-Response Relationships and Risk Assessment

    SciTech Connect

    Strom, Daniel J.

    2005-07-05

    The notion of a dose-response relationship was probably invented shortly after the discovery of poisons, the invention of alcoholic beverages, and the bringing of fire into a confined space in the forgotten depths of ancient prehistory. The amount of poison or medicine ingested can easily be observed to affect the behavior, health, or sickness outcome. Threshold effects, such as death, could be easily understood for intoxicants, medicine, and poisons. As Paracelsus (1493-1541), the 'father' of modern toxicology said, 'It is the dose that makes the poison.' Perhaps less obvious is the fact that implicit in such dose-response relationships is also the notion of dose rate. Usually, the dose is administered fairly acutely, in a single injection, pill, or swallow; a few puffs on a pipe; or a meal of eating or drinking. The same amount of intoxicants, medicine, or poisons administered over a week or month might have little or no observable effect. Thus, before the discovery of ionizing radiation in the late 19th century, toxicology ('the science of poisons') and pharmacology had deeply ingrained notions of dose-response relationships. This chapter demonstrates that the notion of a dose-response relationship for ionizing radiation is hopelessly simplistic from a scientific standpoint. While useful from a policy or regulatory standpoint, dose-response relationships cannot possibly convey enough information to describe the problem from a quantitative view of radiation biology, nor can they address societal values. Three sections of this chapter address the concepts, observations, and theories that contribute to the scientific input to the practice of managing risks from exposure to ionizing radiation. The presentation begins with irradiation regimes, followed by responses to high and low doses of ionizing radiation, and a discussion of how all of this can inform radiation risk management. The knowledge that is really needed for prediction of individual risk is presented

  19. Developing Guidelines for Assessing Visual Analytics Environments

    SciTech Connect

    Scholtz, Jean

    2011-07-01

    In this paper, we develop guidelines for evaluating visual analytic environments based on a synthesis of reviews for the entries to the 2009 Visual Analytics Science and Technology (VAST) Symposium Challenge and from a user study with professional intelligence analysts. By analyzing the 2009 VAST Challenge reviews we gained a better understanding of what is important to our reviewers, both visualization researchers and professional analysts. We also report on a small user study with professional analysts to determine the important factors that they use in evaluating visual analysis systems. We then looked at guidelines developed by researchers in various domains and synthesized these into an initial set for use by others in the community. In a second part of the user study, we looked at guidelines for a new aspect of visual analytic systems – the generation of reports. Future visual analytic systems have been challenged to help analysts generate their reports. In our study we worked with analysts to understand the criteria they used to evaluate the quality of analytic reports. We propose that this knowledge will be useful as researchers look at systems to automate some of the report generation.1 Based on these efforts, we produced some initial guidelines for evaluating visual analytic environment and for evaluation of analytic reports. It is important to understand that these guidelines are initial drafts and are limited in scope because of the type of tasks for which the visual analytic systems used in the studies in this paper were designed. More research and refinement is needed by the Visual Analytics Community to provide additional evaluation guidelines for different types of visual analytic environments.

  20. Assessing Causality in a Complex Security Environment

    DTIC Science & Technology

    2015-01-01

    how. “The Arab Spring. That shows that the image of an Iraqi woman holding up her purple fingertip after having voted, it resonated with the entire...Complex Future? As difficult as it is to engage in causal prediction and causal assessment in the present, there are reasons to wonder if it will

  1. Developing Guidelines for Assessing Visual Analytics Environments

    SciTech Connect

    Scholtz, Jean

    2011-09-22

    Visual analytic systems can be evaluated from a user perspective with quantitative metrics (i.e., time to complete the analysis or the accuracy of the solution found). However, qualitative measures are also useful in a user assessment. These include such measures as the utility of the interactive visualizations in the analysis process and the user's assessment of the efficiency of the analytic process. Quantitative measures can be found if data sets with embedded ground truth are used for analysis. Qualitative measures are more elusive. In this paper we report on an experiment with professional analysts who ranked five of submissions to the VAST 2009 Challenge and provided the rationale for their rankings. Their comments were used in conjunction with a meta-analysis of the 2009 VAST Challenge reviews to produce a set of guidelines for visual analytic systems. As visual analytic software is expected to eventually help in all aspects of analysis, we expect to see future systems provide more help with generating the final report. Hence, researchers also need to have an understanding of what makes a good analytic product. Therefore we asked the analysts to rank the situational assessments of four grand challenge entries and to provide comments on those assessments. We used these comments to produce guidelines for researchers to use in evaluating their analytic reports.

  2. [Regional atmospheric environment risk source identification and assessment].

    PubMed

    Zhang, Xiao-Chun; Chen, Wei-Ping; Ma, Chun; Zhan, Shui-Fen; Jiao, Wen-Tao

    2012-12-01

    Identification and assessment for atmospheric environment risk source plays an important role in regional atmospheric risk assessment and regional atmospheric pollution prevention and control. The likelihood exposure and consequence assessment method (LEC method) and the Delphi method were employed to build a fast and effective method for identification and assessment of regional atmospheric environment risk sources. This method was applied to the case study of a large coal transportation port in North China. The assessment results showed that the risk characteristics and the harm degree of regional atmospheric environment risk source were in line with the actual situation. Fast and effective identification and assessment of risk source has laid an important foundation for the regional atmospheric environmental risk assessment and regional atmospheric pollution prevention and control.

  3. Assessing the Physical Environment of Emergency Departments

    PubMed Central

    Goodarzi, Hassan; Javadzadeh, Hamidreza; Hassanpour, Kasra

    2015-01-01

    Background: Emergency Department (ED) is considered to be the heart of a hospital. Based on many studies, a well-organized physical environment can enhance efficacy. Objectives: In this study, we aimed to investigate the influence of physical environment in EDs on efficacy. Materials and Methods: This analytical cross-sectional study was conducted via the faculty members of the ED and residents of Shahid Beheshti University of Medical Sciences in Tehran, Iran. Data were collected using a predefined questionnaire. Descriptive statistics and ANOVA were used to analyze the data. Results: Sixty-two participants, including 21 females and 41 males, completed the questionnaires. The mean age of the participants was 37 years (SD: 8.42). The mean work experience was 8 years (SD: 4.52) and all the studied variables varied within a range of 3.3 - 4.2. Time indices had the highest mean among variables followed by capacity, work space, treatment units, critical care units and, triage indices, respectively. Conclusions: In general, time indices including length of patient stay in the ED and space capacity, emphasizing the need to address these shortcomings. PMID:26839860

  4. Assessment of Lower Doses of Intravitreous Bevacizumab for Retinopathy of Prematurity: A Phase 1 Dosing Study.

    PubMed

    Wallace, David K; Kraker, Raymond T; Freedman, Sharon F; Crouch, Eric R; Hutchinson, Amy K; Bhatt, Amit R; Rogers, David L; Yang, Michael B; Haider, Kathryn M; VanderVeen, Deborah K; Siatkowski, R Michael; Dean, Trevano W; Beck, Roy W; Repka, Michael X; Smith, Lois E; Good, William V; Hartnett, Mary Elizabeth; Kong, Lingkun; Holmes, Jonathan M

    2017-06-01

    Intravitreous bevacizumab (0.25 to 0.625 mg) is increasingly used to treat type 1 retinopathy of prematurity (ROP), but there remain concerns about systemic toxicity. A much lower dose may be effective while reducing systemic risk. To find a dose of intravitreous bevacizumab that was lower than previously used for severe ROP, was effective in this study, and could be tested in future larger studies. Between May 2015 and September 2016, 61 premature infants with type 1 ROP in 1 or both eyes were enrolled in a masked, multicenter, phase 1 dose de-escalation study. One eye of 10 to 14 infants received 0.25 mg of intravitreous bevacizumab. If successful, the dose was reduced for the next group of infants (to 0.125 mg, then 0.063 mg, and finally 0.031 mg). Diluted bevacizumab was delivered using 300 µL syringes with 5/16-inch, 30-gauge fixed needles. Bevacizumab injections at 0.25 mg, 0.125 mg, 0.063 mg, and 0.031 mg. Success was defined as improvement in preinjection plus disease or zone I stage 3 ROP by 5 days after injection or sooner, and no recurrence of type 1 ROP or severe neovascularization requiring additional treatment within 4 weeks. Fifty-eight of 61 enrolled infants had 4-week outcomes completed; mean birth weight was 709 g and mean gestational age was 24.9 weeks. Success was achieved in 11 of 11 eyes at 0.25 mg, 14 of 14 eyes at 0.125 mg, 21 of 24 eyes at 0.063 mg, and 9 of 9 eyes at 0.031 mg. A dose of bevacizumab as low as 0.031 mg was effective in 9 of 9 eyes in this phase 1 study and warrants further investigation. Identifying a lower effective dose of bevacizumab may reduce the risk for neurodevelopmental disability or detrimental effects on other organs.

  5. Dose assessment of an accidental exposure at the IPNS

    SciTech Connect

    Campos Torres, M.M.

    1995-02-01

    Seven different methods were used to estimate the dose rate to a female worker who was accidentally exposed in the neutron PHOENIX beamline at the IPNS. Theoretical and measured entrance dose ranged from 550 mrem/min to 2850 mrem/min. Theoretical estimates were based on a Monte Carlo simulation of a spectrum provided by IPNS (Crawford Spectrum). Dose measurements were made with TLDs on phantoms and with ionization chambers in a water phantom. Estimates of the whole body total effective dose equivalent (TEDE) rate ranged from 5.2 mrem/min to 840 mrem/min. Assumed and measured quality factors ranged from 2.6 to 11.8. Cytogenetic analyses of blood samples detected no positive exposure. The recommended TEDE rate was 158 mrem/min. The TEDE was 750 mrem.

  6. Dose assessment of an accidental exposure at IPNS

    SciTech Connect

    Torres, M.M.C.

    1996-05-01

    Seven different methods were used to estimate the dose rate to a female worker who was accidentally exposed in the neutron PHOENIX beamline at the IPNS. Theoretical and measured entrance dose rates ranged from 550 mrem/min to 2,850 mrem/min. Theoretical estimates were based on a Monte Carlo simulation of a spectrum provided by IPNS (Crawford Spectrum). Dose measurements were made with TLDs on phantoms and with ionization chambers in a water phantom. Estimates of the whole body total effective dose equivalent (TEDE) rate ranged from 5.2 mrem/min to 840 mrem/min. Assumed and measured quality factors ranged from 2.6 to 11.8. Cytogenic analyses of blood samples detected no positive exposure. The recommended TEDE rate was 158 mrem/min. The TEDE was 750 mrem.

  7. Fetal and maternal dose assessment for diagnostic scans during pregnancy

    NASA Astrophysics Data System (ADS)

    Rafat Motavalli, Laleh; Miri Hakimabad, Hashem; Hoseinian Azghadi, Elie

    2016-05-01

    Despite the concerns about prenatal exposure to ionizing radiation, the number of nuclear medicine examinations performed for pregnant women increased in the past decade. This study attempts to better quantify radiation doses due to diagnostic nuclear medicine procedures during pregnancy with the help of our recently developed 3, 6, and 9 month pregnant hybrid phantoms. The reference pregnant models represent the adult female international commission on radiological protection (ICRP) reference phantom as a base template with a fetus in her gravid uterus. Six diagnostic scintigraphy scans using different radiopharmaceuticals were selected as typical diagnostic nuclear medicine procedures. Furthermore, the biokinetic data of radioiodine was updated in this study. A compartment representing iodide in fetal thyroid was addressed explicitly in the biokinetic model. Calculations were performed using the Monte Carlo transport method. Tabulated dose coefficients for both maternal and fetal organs are provided. The comparison was made with the previously published fetal doses calculated for stylized pregnant female phantoms. In general, the fetal dose in previous studies suffers from an underestimation of up to 100% compared to fetal dose at organ level in this study. A maximum of difference in dose was observed for the fetal thyroid compared to the previous studies, in which the traditional models did not contain the fetal thyroid. Cumulated activities of major source organs are primarily responsible for the discrepancies in the organ doses. The differences in fetal dose depend on several other factors including chord length distribution between fetal organs and maternal major source organs, and anatomical differences according to gestation periods. Finally, considering the results of this study, which was based on the realistic pregnant female phantoms, a more informed evaluation of the risks and benefits of the different procedures could be made.

  8. Assessment of potential doses to workers during postulated accident conditions at the Waste Isolation Pilot Plant

    SciTech Connect

    Hoover, M.D.; Farrell, R.F.; Newton, G.J.

    1995-12-01

    The recent 1995 WIPP Safety Analysis Report (SAR) Update provided detailed analyses of potential radiation doses to members of the public at the site boundary during postulated accident scenarios at the U.S. Department of Energy`s Waste Isolation Pilot Plant (WIPP). The SAR Update addressed the complete spectrum of potential accidents associated with handling and emplacing transuranic waste at WIPP, including damage to waste drums from fires, punctures, drops, and other disruptions. The report focused on the adequacy of the multiple layers of safety practice ({open_quotes}defense-in-depth{close_quotes}) at WIPP, which are designed to (1) reduce the likelihood of accidents and (2) limit the consequences of those accidents. The safeguards which contribute to defense-in-depth at WIPP include a substantial array of inherent design features, engineered controls, and administrative procedures. The SAR Update confirmed that the defense-in-depth at WIPP is adequate to assure the protection of the public and environment. As a supplement to the 1995 SAR Update, we have conducted additional analyses to confirm that these controls will also provide adequate protection to workers at the WIPP. The approaches and results of the worker dose assessment are summarized here. In conformance with the guidance of DOE Standard 3009-94, we emphasize that use of these evaluation guidelines is not intended to imply that these numbers constitute acceptable limits for worker exposures under accident conditions. However, in conjunction with the extensive safety assessment in the 1995 SAR Update, these results indicate that the Carlsbad Area Office strategy for the assessment of hazards and accidents assures the protection of workers, members of the public, and the environment.

  9. Methods for estimating doses to organisms from radioactive materials released into the aquatic environment

    SciTech Connect

    Baker, D.A.; Soldat, J.K.

    1992-06-01

    The US Department of Energy recently published an interim dose limit of 1 rad d{sup {minus}1} for controlling the radiation exposure of nature aquatic organisms. A computer program named CRITR, developed previously for calculating radiation doses to aquatic organisms and their predators, has been updated as an activity of the Hanford Site Surface Environmental Surveillance Project to facilitate demonstration of compliance with this limit. This report presents the revised models and the updated computer program, CRITR2, for the assessment of radiological doses to aquatic organisms and their predators; tables of the required input parameters are also provided. Both internal and external doses to fish, crustacea, mollusks, and algae, as well as organisms that subsist on them, such as muskrats, raccoons, and ducks, may be estimated using CRITR2. Concentrations of radionuclides in the water to which the organisms are exposed may be entered directly into the user-input file or may be calculated from a source term and standard dilution models developed for the National Council on Radiation Protection and Measurements.

  10. National Built Environment Health Impact Assessment Model ...

    EPA Pesticide Factsheets

    Behavioral (activity, diet, social interaction) and exposure (air pollution, traffic injury, and noise) related health impacts of land use and transportation investment decisions are becoming better understood and quantified. Research has shown relationships between density, mix, street connectivity, access to parks, shops, transit, presence of sidewalks and bikeways, and healthy food with physical activity, obesity, cardiovascular disease, type II diabetes, and some mental health outcomes. This session demonstrates successful integration of health impact assessment into multiple scenario planning tool platforms. Detailed evidence on chronic disease and related costs associated with contrasting land use and transportation investments are built into a general-purpose module that can be accessed by multiple platforms. Funders, researchers, and end users of the tool will present a detailed description of the key elements of the approach, how it has been applied, and how will evolve. A critical focus will be placed on equity and social justice inherent within the assessment of health disparities that will be featured in the session. Health impacts of community design have significant cost benefit implications. Recent research is now extending relationships between community design features and chronic disease to health care costs. This session will demonstrate the recent application of this evidence on health impacts to the newly adopted Los Angeles Regional Transpo

  11. National Built Environment Health Impact Assessment Model ...

    EPA Pesticide Factsheets

    Behavioral (activity, diet, social interaction) and exposure (air pollution, traffic injury, and noise) related health impacts of land use and transportation investment decisions are becoming better understood and quantified. Research has shown relationships between density, mix, street connectivity, access to parks, shops, transit, presence of sidewalks and bikeways, and healthy food with physical activity, obesity, cardiovascular disease, type II diabetes, and some mental health outcomes. This session demonstrates successful integration of health impact assessment into multiple scenario planning tool platforms. Detailed evidence on chronic disease and related costs associated with contrasting land use and transportation investments are built into a general-purpose module that can be accessed by multiple platforms. Funders, researchers, and end users of the tool will present a detailed description of the key elements of the approach, how it has been applied, and how will evolve. A critical focus will be placed on equity and social justice inherent within the assessment of health disparities that will be featured in the session. Health impacts of community design have significant cost benefit implications. Recent research is now extending relationships between community design features and chronic disease to health care costs. This session will demonstrate the recent application of this evidence on health impacts to the newly adopted Los Angeles Regional Transpo

  12. Dose assessment according to changes in algorithm in cardiac CT

    NASA Astrophysics Data System (ADS)

    Jang, H. C.; Cho, J. H.; Lee, H. K.; Hong, I. S.; Cho, M. S.; Park, C. S.; Lee, S. Y.; Dong, K. R.; Goo, E. H.; Chung, W. K.; Ryu, Y. H.; Lim, C. S.

    2012-06-01

    The principal objective of this study was to determine the effects of the application of the adaptive statistical iterative reconstruction (ASIR) technique in combination with another two factors (body mass index (BMI) and tube potential) on radiation dose in cardiac computed tomography (CT). For quantitative analysis, regions of interest were positioned on the central region of the great coronary artery, the right coronary artery, and the left anterior descending artery, after which the means and standard deviations of measured CT numbers were obtained. For qualitative analysis, images taken from the major coronary arteries (right coronary, left anterior descending, and left circumflex) were graded on a scale of 1-5, with 5 indicating the best image quality. Effective dose, which was calculated by multiplying the value of the dose length product by a standard conversion factor of 0.017 for the chest, was employed as a measure of radiation exposure dose. In cardiac CT in patients with BMI of less than 25 kg/m2, the use of 40% ASIR in combination with a low tube potential of 100 kVp resulted in a significant reduction in the radiation dose without compromising diagnostic quality. Additionally, the combination of the 120 kVp protocol and the application of 40% ASIR application for patients with BMI higher than 25 kg/m2 yielded similar results.

  13. Institutional Research and Assessment of the External Environment.

    ERIC Educational Resources Information Center

    Groff, Warren H.

    1986-01-01

    Identifies components of a comprehensive assessment of an educational institution's external environment; i.e., demographic trends, social indicators, economic trends, political change, technological advances, changes in the workplace, advances in information technologies, and value shifts. (DMM)

  14. Degraded environments alter prey risk assessment.

    PubMed

    Lönnstedt, Oona M; McCormick, Mark I; Chivers, Douglas P

    2012-01-01

    Elevated water temperatures, a decrease in ocean pH, and an increasing prevalence of severe storms have lead to bleaching and death of the hard corals that underpin coral reef ecosystems. As coral cover declines, fish diversity and abundance declines. How degradation of coral reefs affects behavior of reef inhabitants is unknown. Here, we demonstrate that risk assessment behaviors of prey are severely affected by coral degradation. Juvenile damselfish were exposed to visual and olfactory indicators of predation risk in healthy live, thermally bleached, and dead coral in a series of laboratory and field experiments. While fish still responded to visual cues in all habitats, they did not respond to olfactory indicators of risk in dead coral habitats, likely as a result of alteration or degradation of chemical cues. These cues are critical for learning and avoiding predators, and a failure to respond can have dramatic repercussions for survival and recruitment.

  15. Computational assessment of effective dose and patient specific doses for kilovoltage stereotactic radiosurgery of wet age-related macular degeneration

    NASA Astrophysics Data System (ADS)

    Hanlon, Justin Mitchell

    Age-related macular degeneration (AMD) is a leading cause of vision loss and a major health problem for people over the age of 50 in industrialized nations. The current standard of care, ranibizumab, is used to help slow and in some cases stabilize the process of AMD, but requires frequent invasive injections into the eye. Interest continues for stereotactic radiosurgery (SRS), an option that provides a non-invasive treatment for the wet form of AMD, through the development of the IRay(TM) (Oraya Therapeutics, Inc., Newark, CA). The goal of this modality is to destroy choroidal neovascularization beneath the pigment epithelium via delivery of three 100 kVp photon beams entering through the sclera and overlapping on the macula delivering up to 24 Gy of therapeutic dose over a span of approximately 5 minutes. The divergent x-ray beams targeting the fovea are robotically positioned and the eye is gently immobilized by a suction-enabled contact lens. Device development requires assessment of patient effective dose, reference patient mean absorbed doses to radiosensitive tissues, and patient specific doses to the lens and optic nerve. A series of head phantoms, including both reference and patient specific, was derived from CT data and employed in conjunction with the MCNPX 2.5.0 radiation transport code to simulate treatment and evaluate absorbed doses to potential tissues-at-risk. The reference phantoms were used to evaluate effective dose and mean absorbed doses to several radiosensitive tissues. The optic nerve was modeled with changeable positions based on individual patient variability seen in a review of head CT scans gathered. Patient specific phantoms were used to determine the effect of varying anatomy and gaze. The results showed that absorbed doses to the non-targeted tissues were below the threshold levels for serious complications; specifically the development of radiogenic cataracts and radiation induced optic neuropathy (RON). The effective dose

  16. Experimental assessment of proton dose calculation accuracy in inhomogeneous media.

    PubMed

    Sorriaux, J; Testa, M; Paganetti, H; Orban de Xivry, J; Lee, J A; Traneus, E; Souris, K; Vynckier, S; Sterpin, E

    2017-06-01

    Proton therapy with Pencil Beam Scanning (PBS) has the potential to improve radiotherapy treatments. Unfortunately, its promises are jeopardized by the sensitivity of the dose distributions to uncertainties, including dose calculation accuracy in inhomogeneous media. Monte Carlo dose engines (MC) are expected to handle heterogeneities better than analytical algorithms like the pencil-beam convolution algorithm (PBA). In this study, an experimental phantom has been devised to maximize the effect of heterogeneities and to quantify the capability of several dose engines (MC and PBA) to handle these. An inhomogeneous phantom made of water surrounding a long insert of bone tissue substitute (1×10×10 cm(3)) was irradiated with a mono-energetic PBS field (10×10 cm(2)). A 2D ion chamber array (MatriXX, IBA Dosimetry GmbH) lied right behind the bone. The beam energy was such that the expected range of the protons exceeded the detector position in water and did not attain it in bone. The measurement was compared to the following engines: Geant4.9.5, PENH, MCsquare, as well as the MC and PBA algorithms of RayStation (RaySearch Laboratories AB). For a γ-index criteria of 2%/2mm, the passing rates are 93.8% for Geant4.9.5, 97.4% for PENH, 93.4% for MCsquare, 95.9% for RayStation MC, and 44.7% for PBA. The differences in γ-index passing rates between MC and RayStation PBA calculations can exceed 50%. The performance of dose calculation algorithms in highly inhomogeneous media was evaluated in a dedicated experiment. MC dose engines performed overall satisfactorily while large deviations were observed with PBA as expected. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. Assessment of Environment-Therapy Systems: The Group Atmosphere Scale

    ERIC Educational Resources Information Center

    Silbergeld, Sam; And Others

    1975-01-01

    The Group Atmosphere Scale (GAS) was developed to measure systematically the psychosocial environment of therapy groups. Twelve content subscales, each containing 10 true-false items, assess the consensual psychosocial environment. Several of these serve as indicators of group cohesion and conformity. The GAS makes feasible a comparison of…

  18. Assessing Home Environment for Early Child Development in Pakistan

    ERIC Educational Resources Information Center

    Nadeem, Sanober; Rafique, Ghazala; Khowaja, Liaquat; Yameen, Anjum

    2014-01-01

    Family environment plays a very important role in early child development and the availability of stimulating material in the early years of a child's life is crucial for optimising development. The Home Observation for Measurement of the Environment (HOME) inventory is one of the most widely used measures to assess the quality and quantity of…

  19. Assessing Student Perceptions of Internet-Based Online Learning Environments.

    ERIC Educational Resources Information Center

    Teh, George P. L.

    1999-01-01

    Reports on a study of Web-based learning environments in Singapore that focuses on the cross-validation of the Geography Classroom Environment Inventory (GCEI) which assesses undergraduate students' perceptions of psychosocial aspects of their Web-based instruction. Examines gender equity, instructional innovation, internal consistency…

  20. Dietary and Built Environment Assessment in a Latino Community

    ERIC Educational Resources Information Center

    Khan, Sarah; Calloway, Stephanie A.; Maida, I. Tatiana; Rakel, David P.

    2012-01-01

    Background: Assessment of basic dietary intake and community nutrition environment is lacking and needed to improve health outcomes for the growing U.S. Latino community. Purpose: The dietary intake and community nutrition environment of a Latino population in the Midwest was evaluated. Methods: In a community clinic, Block Food Frequency…

  1. Dietary and Built Environment Assessment in a Latino Community

    ERIC Educational Resources Information Center

    Khan, Sarah; Calloway, Stephanie A.; Maida, I. Tatiana; Rakel, David P.

    2012-01-01

    Background: Assessment of basic dietary intake and community nutrition environment is lacking and needed to improve health outcomes for the growing U.S. Latino community. Purpose: The dietary intake and community nutrition environment of a Latino population in the Midwest was evaluated. Methods: In a community clinic, Block Food Frequency…

  2. Assessing Home Environment for Early Child Development in Pakistan

    ERIC Educational Resources Information Center

    Nadeem, Sanober; Rafique, Ghazala; Khowaja, Liaquat; Yameen, Anjum

    2014-01-01

    Family environment plays a very important role in early child development and the availability of stimulating material in the early years of a child's life is crucial for optimising development. The Home Observation for Measurement of the Environment (HOME) inventory is one of the most widely used measures to assess the quality and quantity of…

  3. Assessing Student Perceptions of Internet-Based Online Learning Environments.

    ERIC Educational Resources Information Center

    Teh, George P. L.

    1999-01-01

    Reports on a study of Web-based learning environments in Singapore that focuses on the cross-validation of the Geography Classroom Environment Inventory (GCEI) which assesses undergraduate students' perceptions of psychosocial aspects of their Web-based instruction. Examines gender equity, instructional innovation, internal consistency…

  4. The Experience of Assessing Out-of-School Learning Environments

    ERIC Educational Resources Information Center

    Kiriktas, Halit; Eslek, Sinan

    2017-01-01

    This study aimed to investigate out-of-school learning environments within the borders of the province of Izmir in terms of various parameters. With this purpose, the researchers developed the "Out-Of-School Learning Environments Assessment Survey." The study used the screening model, which is a descriptive research method. In the scope…

  5. Assessment of patient and occupational dose in established and new applications of MDCT fluoroscopy.

    PubMed

    Joemai, Raoul M S; Zweers, Dirk; Obermann, Wim R; Geleijns, Jacob

    2009-04-01

    This study aimed to assess patient dose and occupational dose in established and new applications of MDCT fluoroscopy. Electronic personal dosimeters were used to measure occupational dose equivalent. Effective patient dose was derived from the recorded dose-length product. Acquisition parameters that were observed during CT fluoroscopy (CTF) provided the basis for the estimation of an entrance skin dose profile. Two hundred ten CT-guided interventional procedures were included in the study. The median effective patient dose was 10 mSv (range, 0.1-235 mSv; 107 procedures). The median peak entrance skin dose was 0.4 Sv (0.1-2.1 Sv; 27 procedures). From 547 measurements of occupational dose equivalent, a median occupational effective dose of 3 muSv per procedure was derived for the interventional radiologists and 0.4 muSv per procedure for the assisting radiologists and radiology technologists. The estimated maximum occupational effective dose reached 0.4 mSv. The study revealed high effective patient doses, up to 235 mSv, mainly for relatively new applications such as CTF-guided radiofrequency ablations using MDCT, vertebroplasty, and percutaneous ethanol injections of tumors. Entrance doses were occasionally in the range of the warning level for deterministic skin effects but were always below the threshold for serious deterministic effects. The complexity of the procedure, expected benefits of the treatment, and general health state of the patient contribute to the justification of observed high effective patient doses.

  6. Respiratory dose assessment of inhaled particles: continuing progress

    EPA Science Inventory

    Internal dose is a key factor for determining the health risk ofinhaled pollutant particles on the one hand and the efficacy ofdrug inhalantsonthe other. Accurateestimation ofrespiratorydose, however, is a difficult task because multiple factors come to play roles in the process....

  7. Respiratory dose assessment of inhaled particles: continuing progress

    EPA Science Inventory

    Internal dose is a key factor for determining the health risk ofinhaled pollutant particles on the one hand and the efficacy ofdrug inhalantsonthe other. Accurateestimation ofrespiratorydose, however, is a difficult task because multiple factors come to play roles in the process....

  8. Assessment of gamma-dose rate in city of Kermanshah

    PubMed Central

    Tavakoli, Mohamad Bagher; Kodamoradi, Ehsan; Shaneh, Zahra

    2012-01-01

    Introduction: Environmental natural radiation measurement is of great importance and interest especially for human health. The induction of genetic disorder and cancer appears to be the most important in an exposed population. Materials and Methods: Measurements of background gamma rays were performed using a mini-rad environmental survey meter at 25 different locations around the city of Kermanshah (a city in the west of Iran). The measurements were also performed at two different time of day one in the morning and the other in the afternoon. At each location and time measurements were repeated for five times and the mean was considered as the background dose at that location. Results and Discussions: Comparison between the measured results in the morning and afternoon has not shown any significant difference (P > 0.95). The maximum and minimum obtained results were 2.63 mSv/y and 1.49 mSv/y, respectively. From the total measurements at 25 sites mean and SD background radiation dose to the population is 2.24 ± 0.25 mSv. Conclusion: The mean radiation dose to the population is about 2.5 times of the world average total external exposure cosmic rays and terrestrial gamma rays dose reported by UNSCEAR. PMID:23555133

  9. A dose assessment associated with landspreading petroleum industry NORM.

    SciTech Connect

    Arnish, J. J.; Smith, K. P.; Blunt, D. L.; Environmental Assessment

    2002-04-01

    As a result of oil and gas production and processing operations, naturally occurring radioactive material (NORM) sometimes accumulates at elevated concentrations in byproduct waste streams. The primary radionuclide of concern in NORM wastes are radium-226 (Ra-226) of the uranium-238 decay series; radium-228 of the thorium-232 decay series is also present, but usually at lower concentrations. The production waste streams most likely to be contaminated by elevated radium concentrations include produced water, scale, and sludge. Scales and sludges removed from production equipment sometimes are disposed of by landspreading, a method in which wastes are spread over the soil surface to allow the hydrocarbon component of the wastes to degrade. The disposal of NORM-contaminated wastes by landspreading was modeled to evaluate potential radiological doses to the general public. A variety of future land use scenarios - including residential, industrial, recreational, and agricultural scenarios - were considered. The waste streams considered included scales and sludges containing NORM above background levels. The RESRAD computer code was used to estimate the radiological doses for the maximally exposed receptor for each scenario. Depending on the land-use scenario, potential exposure pathways evaluated for the general public included external radiation; inhalation of contaminated particulates; inhalation of indoor and outdoor radon-222; inadvertent ingestion of contaminated soil; and ingestion of crops, milk, and meat grown on the property. Potential doses were modeled for a unit concentration of 1 Bq g{sup -1} of Ra-226 in soil. Because dose increases linearly with radium concentration, doses were extrapolated for a range of radium concentrations.

  10. Assessment of dose and DNA damages in individuals exposed to low dose and low dose rate ionizing radiations during computed tomography imaging.

    PubMed

    Kanagaraj, Karthik; Abdul Syed Basheerudeen, Safa; Tamizh Selvan, G; Jose, M T; Ozhimuthu, Annalakshmi; Panneer Selvam, S; Pattan, Sudha; Perumal, Venkatachalam

    2015-08-01

    Computed tomography (CT) is a frequently used imaging modality that contributes to a tenfold increase in radiation exposure to the public when compared to other medical imaging modalities. The use of radiation for therapeutic need is always rationalized on the basis of risk versus benefit thereby increasing concerns on the dose received by patients undergoing CT imaging. Therefore, it was of interest to us to investigate the effects of low dose and low dose-rate X-irradiation in patients who underwent CT imaging by recording the doses received by the eye, forehead and thyroid, and to study the levels of damages in the lymphocytes in vivo. Lithium manganese borate doped with terbium (LMB:Tb) thermo luminescence dosimeters (TLD) were used to record the doses in the patient's (n = 27) eye, forehead, and thyroid and compared with the dose length product (DLP) values. The in vivo DNA damages measured were compared before and after CT imaging using chromosomal aberration (CA) and micronucleus (MN) assays. The overall measured organ dose ranged between 2 ± 0.29 and 520 ± 41.63 mGy for the eye, 0.84 ± 0.29 and 210 ± 20.50 mGy for the forehead, and 1.79 ± 0.43 and 185 ± 0.70 mGy for the thyroid. The in vivo damages measured from the blood lymphocytes of the subjects showed an extremely significant (p < 0.0001) increase in CA frequency and significant (p < 0.001) increase in MN frequency after exposure, compared to before exposure. The results suggest that CT imaging delivers a considerable amount of radiation dose to the eye, forehead, and thyroid, and the observed increase in the CA and MN frequencies show low dose radiation effects calling for protective regulatory measures to increase patient's safety. This study is the first attempt to indicate the trend of doses received by the patient's eye, forehead and thyroid and measured directly in contrast to earlier values obtained by extrapolation from phantoms, and to assess the in vivo low dose effects in an Indian

  11. An approach for assessing human exposures to chemical mixtures in the environment

    SciTech Connect

    Rice, Glenn MacDonell, Margaret; Hertzberg, Richard C.; Teuschler, Linda; Picel, Kurt; Butler, Jim; Chang, Young-Soo; Hartmann, Heidi

    2008-11-15

    Humans are exposed daily to multiple chemicals, including incidental exposures to complex chemical mixtures released into the environment and to combinations of chemicals that already co-exist in the environment because of previous releases from various sources. Exposures to chemical mixtures can occur through multiple pathways and across multiple routes. In this paper, we propose an iterative approach for assessing exposures to environmental chemical mixtures; it is similar to single-chemical approaches. Our approach encompasses two elements of the Risk Assessment Paradigm: Problem Formulation and Exposure Assessment. Multiple phases of the assessment occur in each element of the paradigm. During Problem Formulation, analysts identify and characterize the source(s) of the chemical mixture, ensure that dose-response and exposure assessment measures are concordant, and develop a preliminary evaluation of the mixture's fate. During Exposure Assessment, analysts evaluate the fate of the chemicals comprising the mixture using appropriate models and measurement data, characterize the exposure scenario, and estimate human exposure to the mixture. We also describe the utility of grouping the chemicals to be analyzed based on both physical-chemical properties and an understanding of environmental fate. In the article, we also highlight the need for understanding of changes in the mixture composition in the environment due to differential transport, differential degradation, and differential partitioning to other media. The section describes the application of the method to various chemical mixtures, highlighting issues associated with assessing exposures to chemical mixtures in the environment.

  12. The environmental assessment instrument: harnessing the environment for programmatic success.

    PubMed

    Lavinghouze, S René; Price, Ann W; Parsons, Beverly

    2009-04-01

    This article describes the Environmental Assessment Instrument (EAI), a tool designed to help public health professionals analyze and then engage the environment in which programs operate. The prevailing environment is an important force that must be considered in an integrated systems approach when implementing programs and policies. The Division of Oral Health of the Centers for Disease Control and Prevention developed the EAI to facilitate the ability of a state oral health program to understand their environment and the impact it has on the achievement of performance objectives. EAI results are plotted on a four-quadrant grid that depicts four types of change-stagnant, disruptive, continuous, and sporadic. General strategies are suggested based on these categories of change. By assessing environmental influences, program and policy planners can determine salient leverage points within their environment, identify strategies to address barriers to success, and build on supportive features in the environment.

  13. Assessing Student Transitions in an Online Learning Environment

    ERIC Educational Resources Information Center

    Nakayama, Minoru; Yamamoto, Hiroh

    2011-01-01

    Assessment surveys of students are often conducted in order to evaluate online learning activities. Most surveys measure responses to questions which are based on students' subjective impressions. The purpose of this study is to examine participants' assessments made during the transitional phase in an online learning environment which includes…

  14. Absorbed dose assessment in newborns during x-ray examinations

    NASA Astrophysics Data System (ADS)

    Taipe, Patricia K.; Berrocal, Mariella J.; Carita, Raúl F.

    2012-02-01

    Often a newborn presents breathing problems during the early days of life, i.e. bronchopneumonia, wich are caused in most of cases, by aspirating a mixture of meconium and amniotic fluid. In these cases, it is necessary to make use of a radiograph, requested by the physician to reach a diagnosis. This paper seeks to evaluate the absorbed doses in neonates undergoing a radiograph. For this reason we try to simulate the real conditions in a X-ray room from Lima hospitals. With this finality we perform a simulation made according a questionnaire related to technical data of X-ray equipment, distance between the source and the neonate, and its position to be irradiated. The information obtained has been used to determine the absorbed dose by infants, using the MCNP code. Finally, the results are compared with reference values of international health agencies.

  15. Dose, effect severity, and imparted energy in assessing biological effects.

    PubMed

    Bond, V P

    1995-05-01

    Because of the widespread efforts in cancer radioepidemiological studies to attach a value of absorbed dose to each exposed individual, the notion seems to have become prevalent that dose plays an essential role in the medical determination of the diagnosis and prognosis of the individual. This view is enhanced by the fact that, while the present quantities and units for radiological physics were developed in the context of the acute effects of large exposures to radiation, e.g., in radiotherapy where they still apply well, these same quantities and units have been used, without modification, to apply to cancer radioepidemiology in the context of low level irradiation. A principle purpose of the present communication is to show that, in medicine, dose plays a limited role even in the deterministic application of therapeutic agents, and that diagnosis and estimates of prognosis in medicine are based, not on dose, but on the severity of effect on, or damage to the organ or organs involved in a particular medical condition. Thus it is "going backward" to view estimates of the severity of effect, e.g., the fraction of cells with abnormalities, or killed, as a "biological dosimeter," rather than as a quantitative estimate of the severity of effect. The use of biological indicators is of maximum value in noncancerous disease or injury in which the severity of an effect causative for organ failure and a consequent quantal, e.g., a lethal response in the individual, can be measured with increasing accuracy by modern medical techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Radon dose assessment in underground mines in Brazil.

    PubMed

    Santos, T O; Rocha, Z; Cruz, P; Gouvea, V A; Siqueira, J B; Oliveira, A H

    2014-07-01

    Underground miners are internally exposed to radon, thoron and their short-lived decay products during the mineral processing. There is also an external exposure due to the gamma emitters present in the rock and dust of the mine. However, the short-lived radon decay products are recognised as the main radiation health risk. When inhaled, they are deposited in the respiratory system and may cause lung cancer. To address this concern, concentration measurements of radon and its progeny were performed, the equilibrium factor was determined and the effective dose received was estimated in six Brazilian underground mines. The radon concentration was measured by using E-PERM, AlphaGUARD and CR-39 detectors. The radon progeny was determined by using DOSEman. The annual effective dose for the miners was estimated according to United Nations Scientific Committee on the Effects of Atomic Radiation methodologies. The mean value of the equilibrium factor was 0.4. The workers' estimated effective dose ranged from 1 to 21 mSv a(-1) (mean 9 mSv a(-1)). © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. RADAR realistic animal model series for dose assessment.

    PubMed

    Keenan, Mary A; Stabin, Michael G; Segars, William P; Fernald, Michael J

    2010-03-01

    Rodent species are widely used in the testing and approval of new radiopharmaceuticals, necessitating murine phantom models. As more therapy applications are being tested in animal models, calculating accurate dose estimates for the animals themselves becomes important to explain and control potential radiation toxicity or treatment efficacy. Historically, stylized and mathematically based models have been used for establishing doses to small animals. Recently, a series of anatomically realistic human phantoms was developed using body models based on nonuniform rational B-spline. Realistic digital mouse whole-body (MOBY) and rat whole-body (ROBY) phantoms were developed on the basis of the same NURBS technology and were used in this study to facilitate dose calculations in various species of rodents. Voxel-based versions of scaled MOBY and ROBY models were used with the Vanderbilt multinode computing network (Advanced Computing Center for Research and Education), using geometry and tracking radiation transport codes to calculate specific absorbed fractions (SAFs) with internal photon and electron sources. Photon and electron SAFs were then calculated for relevant organs in all models. The SAF results were compared with values from similar studies found in reference literature. Also, the SAFs were used with standardized decay data to develop dose factors to be used in radiation dose calculations. Representative plots were made of photon electron SAFs, evaluating the traditional assumption that all electron energy is absorbed in the source organs. The organ masses in the MOBY and ROBY models are in reasonable agreement with models presented by other investigators noting that considerable variation can occur between reported masses. Results consistent with those found by other investigators show that absorbed fractions for electrons for organ self-irradiation were significantly less than 1.0 at energies above 0.5 MeV, as expected for many of these small-sized organs

  18. SU-E-T-278: Dose Conformity Index for the Target in a Multitarget Environment

    SciTech Connect

    Harikrishnaperumal, Sudahar

    2015-06-15

    Purpose: The existing conformity index formulations are failing when multiple targets present outside the target of interest with same or different dose prescriptions. In the present study a novel methodology is introduced to solve this issue. Methods: The conformity index used by Nakamura et al (Int J Radiat Oncol Biol Phys 2001; 51(5):1313–1319) is taken as the base for this methodology. In this proposal, the prescription isodose volume (PIV) which normally includes the normal tissue and other target regions is restricted as PIV in annular regions of different thickness around the target of interest. The graphical line plotted between the thickness of annular region and the corresponding conformity index, will increase in the beginning and will reach a flat region, then it will increase again. The second increase in the conformity index depends basically on the distance between the targets, dose prescriptions, and size of the targets. The conformity index in the flat region should be the conformity index of the target of interest. This methodology was validated on dual target environment on a skull phantom in Multiplan planning system (Accuray Inc. Sunnyvale, USA) Results: When the surrounding target’s (sphere) size is changed from 1.5cm to 6cm diameter, the conformity index of the target of interest (3cm diameter) changed from 1.09 to 1.25. When the distance between the targets changed from 7.5cm to 2.5cm, the conformity index changed from 1.10 to 1.17. Similarly, when the prescribed dose changed from 25Gy to 50Gy the conformity index changed from 1.09 to 1.42. These values were above 2.0 when Nakamura et al formula was used. Conclusion: The proposed conformity index methodology eliminates the influence of surrounding targets to a greater extend. However, the limitations of this method should be studied further. Application of this method in clinical situations is the future scope.

  19. Environment, safety and health progress assessment manual. Volume 1

    SciTech Connect

    Not Available

    1992-12-01

    On June 27, 1989, the Secretary of Energy announced a 10-Point Initiative to strengthen environment, safety, and health (ES&H) programs, and waste management activities at DOE production, research, and testing facilities. One of the points involved conducting dent Tiger Team Assessments of DOE operating facilities. The Office of Special independent Projects (OSP), EH-5, in the Office of the Assistant Secretary for Environment, Safety and Health, EH-1, was assigned the responsibility to conduct the Tiger Team Assessments. Through June 1992, a total of 35 Tiger Team Assessments were completed. The Secretary directed that Corrective Action Plans be developed and implemented to address the concerns identified by the Tiger Teams. In March 1991, the Secretary approved a plan for assessments that are ``more focused, concentrating on ES&H management, ES&H corrective actions, self-assessment programs, and root-cause related issues.`` In July 1991, the Secretary approved the initiation of ES&H Progress Assessments, as a followup to the Tiger Team Assessments, and in the continuing effort to institutionalize the self-assessment process and line management accountability in the ES&H areas. This manual documents the processes to be used to perform the ES&H Progress Assessments. It was developed based upon the lessons learned from Tiger Team Assessments, the two pilot Progress Assessments, and Progress Assessments that have been completed. The manual will be updated periodically to reflect lessons learned or changes in policy.

  20. Environment, safety and health progress assessment manual. Volume 2, Appendices

    SciTech Connect

    Not Available

    1992-12-01

    On June 27, 1989, the Secretary of Energy announced a 1O-Point Initiative to strengthen environment,safety, and health (ES&H) programs, and waste management activities at involved conducting DOE production, research, and testing facilities. One of the points independent Tiger Team Assessments of DOE operating facilities. The Office of Special Projects (OSP), EH-5, in the Office of the Assistant Secretary for Environment, Safety and Health, EH-1, was assigned the responsibility to conduct the Tiger Team Assessments. Through June 1992, a total of 35 Tiger Team Assessments were completed. The Secretary directed that Corrective Action Plans be developed and implemented to address the concerns identified by the Tiger Teams. In March 1991, the Secretary approved a plan for assessments that are ``more focused, concentrating on ES&H management, ES&H corrective actions, self-assessment programs, and root-cause related issues.`` In July 1991, the Secretary approved the initiation of ES&H Progress Assessments, as a followup to the Tiger Team Assessments, and in the continuing effort to institutionalize the self-assessment process and line management accountability in the ES&H areas. This volume contains appendices to the Environment, Safety and Health Progress Assessment Manual.

  1. Vulnerability assessment of atmospheric environment driven by human impacts.

    PubMed

    Zhang, Yang; Shen, Jing; Ding, Feng; Li, Yu; He, Li

    2016-11-15

    Atmospheric environment quality worsening is a substantial threat to public health worldwide, and in many places, air pollution due to the intensification of the human activity is increasing dramatically. However, no studies have been investigated the integration of vulnerability assessment and atmospheric environment driven by human impacts. The objective of this study was to identify and prioritize the undesirable environmental changes as an early warning system for environment managers and decision makers in term of human, atmospheric environment, and social economic elements. We conduct a vulnerability assessment method of atmospheric environment associated with human impact, this method integrates spatial context of Geographic Information System (GIS) tool, multi-criteria decision analysis (MCDA) method, ordered weighted averaging (OWA) operators under the Exposure-Sensitivity- Adaptive Capacity (ESA) framework. Decision makers can find out relevant vulnerability assessment results with different vulnerable attitudes. In the Beijing-Tianjin-Hebei (BTH) region, China, we further applied this developed method and proved it to be reliable and consistent with the China Environmental Status Bulletin. Results indicate that the vulnerability of atmospheric environment in the BTH region is not optimistic, and environment managers should do more about air pollution. Thus, the most appropriate strategic decision and development program of city or state can be picked out assisting by the vulnerable results. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Digital breast tomosynthesis: Dose and image quality assessment.

    PubMed

    Maldera, A; De Marco, P; Colombo, P E; Origgi, D; Torresin, A

    2017-01-01

    The aim of this work was to evaluate how different acquisition geometries and reconstruction parameters affect the performance of four digital breast tomosynthesis (DBT) systems (Senographe Essential - GE, Mammomat Inspiration - Siemens, Selenia Dimensions - Hologic and Amulet Innovality - Fujifilm) on the basis of a physical characterization. Average Glandular Dose (AGD) and image quality parameters such as in-plane/in-depth resolution, signal difference to noise ratio (SDNR) and artefact spread function (ASF) were examined. Measured AGD values resulted below EUREF limits for 2D imaging. A large variability was recorded among the investigated systems: the mean dose ratio DBT/2D ranged between 1.1 and 1.9. In-plane resolution was in the range: 2.2mm(-1)-3.8mm(-1) in chest wall-nipple direction. A worse resolution was found for all devices in tube travel direction. In-depth resolution improved with increasing scan angle but was also affected by the choice of reconstruction and post-processing algorithms. The highest z-resolution was provided by Siemens (50°, FWHM=2.3mm) followed by GE (25°, FWHM=2.8mm), while the Fujifilm HR showed the lowest one, despite its wide scan angle (40°, FWHM=4.1mm). The ASF was dependent on scan angle: smaller range systems showed wider ASF curves; however a clear relationship was not found between scan angle and ASF, due to the different post processing and reconstruction algorithms. SDNR analysis, performed on Fujifilm system, demonstrated that pixel binning improves detectability for a fixed dose/projection. In conclusion, we provide a performance comparison among four DBT systems under a clinical acquisition mode. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  3. Ecological validity of virtual environments to assess human navigation ability

    PubMed Central

    van der Ham, Ineke J. M.; Faber, Annemarie M. E.; Venselaar, Matthijs; van Kreveld, Marc J.; Löffler, Maarten

    2015-01-01

    Route memory is frequently assessed in virtual environments. These environments can be presented in a fully controlled manner and are easy to use. Yet they lack the physical involvement that participants have when navigating real environments. For some aspects of route memory this may result in reduced performance in virtual environments. We assessed route memory performance in four different environments: real, virtual, virtual with directional information (compass), and hybrid. In the hybrid environment, participants walked the route outside on an open field, while all route information (i.e., path, landmarks) was shown simultaneously on a handheld tablet computer. Results indicate that performance in the real life environment was better than in the virtual conditions for tasks relying on survey knowledge, like pointing to start and end point, and map drawing. Performance in the hybrid condition however, hardly differed from real life performance. Performance in the virtual environment did not benefit from directional information. Given these findings, the hybrid condition may offer the best of both worlds: the performance level is comparable to that of real life for route memory, yet it offers full control of visual input during route learning. PMID:26074831

  4. U.S. EPA Superfund Program's Policy for Risk and Dose Assessment

    SciTech Connect

    Walker, Stuart

    2008-01-15

    The Environmental Protection Agency (EPA) Office of Superfund Remediation and Technology Innovation (OSRTI) has primary responsibility for implementing the long-term (non-emergency) portion of a key U.S. law regulating cleanup: the Comprehensive Environmental Response, Compensation and Liability Act, CERCLA, nicknamed 'Superfund'. The purpose of the Superfund program is to protect human health and the environment over the long term from releases or potential releases of hazardous substances from abandoned or uncontrolled hazardous waste sites. The focus of this paper is on risk and dose assessment policies and tools for addressing radioactively contaminated sites by the Superfund program. EPA has almost completed two risk assessment tools that are particularly relevant to decommissioning activities conducted under CERCLA authority. These are the: 1. Building Preliminary Remediation Goals for Radionuclides (BPRG) electronic calculator, and 2. Radionuclide Outdoor Surfaces Preliminary Remediation Goals (SPRG) electronic calculator. EPA developed the BPRG calculator to help standardize the evaluation and cleanup of radiologically contaminated buildings at which risk is being assessed for occupancy. BPRGs are radionuclide concentrations in dust, air and building materials that correspond to a specified level of human cancer risk. The intent of SPRG calculator is to address hard outside surfaces such as building slabs, outside building walls, sidewalks and roads. SPRGs are radionuclide concentrations in dust and hard outside surface materials. EPA is also developing the 'Radionuclide Ecological Benchmark' calculator. This calculator provides biota concentration guides (BCGs), also known as ecological screening benchmarks, for use in ecological risk assessments at CERCLA sites. This calculator is intended to develop ecological benchmarks as part of the EPA guidance 'Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk

  5. Modelling the dynamics of ambient dose rates induced by radiocaesium in the Fukushima terrestrial environment.

    PubMed

    Gonze, Marc-André; Mourlon, Christophe; Calmon, Philippe; Manach, Erwan; Debayle, Christophe; Baccou, Jean

    2016-09-01

    Since the Fukushima accident, Japanese scientists have been intensively monitoring ambient radiations in the highly contaminated territories situated within 80 km of the nuclear site. The surveys that were conducted through mainly carborne, airborne and in situ gamma-ray measurement devices, enabled to efficiently characterize the spatial distribution and temporal evolution of air dose rates induced by Caesium-134 and Caesium-137 in the terrestrial systems. These measurements revealed that radiation levels decreased at rates greater than expected from physical decay in 2011-2012 (up to a factor of 2), and dependent on the type of environment (i.e. urban, agricultural or forest). Unlike carborne measurements that may have been strongly influenced by the depuration of road surfaces, no obvious reason can be invoked for airborne measurements, especially above forests that are known to efficiently retain and recycle radiocaesium. The purpose of our research project is to develop a comprehensive understanding of the data acquired by Japanese, and identify the environmental mechanisms or factors that may explain such decays. The methodology relies on the use of a process-based and spatially-distributed dynamic model that predicts radiocaesium transfer and associated air dose rates inside/above a terrestrial environment (e.g., forests, croplands, meadows, bare soils and urban areas). Despite the lack of site-specific data, our numerical study predicts decrease rates that are globally consistent with both aerial and in situ observations. The simulation at a flying altitude of 200 m indicated that ambient radiation levels decreased over the first 12 months by about 45% over dense urban areas, 15% above evergreen coniferous forests and between 2 and 12% above agricultural lands, owing to environmental processes that are identified and discussed. In particular, we demonstrate that the decrease over evergreen coniferous regions might be due the combined effects of canopy

  6. Modelling the dynamics of ambient dose rates induced by radiocaesium in the Fukushima terrestrial environment

    NASA Astrophysics Data System (ADS)

    Gonze, Marc-André; Mourlon, Christophe; Calmon, Philippe; Manach, Erwan; Debayle, Christophe; Baccou, Jean

    2017-09-01

    Since the Fukushima accident, Japanese scientists have been intensively monitoring ambient radiations in the highly contaminated territories situated within 80 km of the nuclear site. The surveys that were conducted through mainly carborne, airborne and in situ gamma-ray measurement devices, enabled to efficiently characterize the spatial distribution and temporal evolution of air dose rates induced by Caesium-134 and Caesium-137 in the terrestrial systems. These measurements revealed that radiation levels decreased at rates greater than expected from physical decay in 2011-2012 (up to a factor of 2), and dependent on the type of environment (i.e. urban, agricultural or forest). Unlike carborne measurements that may have been strongly influenced by the depuration of road surfaces, no obvious reason can be invoked for airborne measurements, especially above forests that are known to efficiently retain and recycle radiocaesium. The purpose of our research project is to develop a comprehensive understanding of the data acquired by Japanese, and identify the environmental mechanisms or factors that may explain such decays. The methodology relies on the use of a process-based and spatially-distributed dynamic model that predicts radiocaesium transfer and associated air dose rates inside/above a terrestrial environment (e.g., forests, croplands, meadows, bare soils and urban areas). Despite the lack of site-specific data, our numerical study predicts decrease rates that are globally consistent with both aerial and in situ observations. The simulation at a flying altitude of 200 m indicated that ambient radiation levels decreased over the first 12 months by about 45% over dense urban areas, 15% above evergreen coniferous forests and between 2 and 12% above agricultural lands, owing to environmental processes that are identified and discussed. In particular, we demonstrate that the decrease over evergreen coniferous regions might be due the combined effects of canopy

  7. Dose-response relationship between hand-transmitted vibration and hand-arm vibration syndrome in a tropical environment.

    PubMed

    Su, Anselm Ting; Maeda, Setsuo; Fukumoto, Jin; Darus, Azlan; Hoe, Victor C W; Miyai, Nobuyuki; Isahak, Marzuki; Takemura, Shigeki; Bulgiba, Awang; Yoshimasu, Kouichi; Miyashita, Kazuhisa

    2013-07-01

    The dose-response relationship for hand-transmitted vibration has been investigated extensively in temperate environments. Since the clinical features of hand-arm vibration syndrome (HAVS) differ between the temperate and tropical environment, we conducted this study to investigate the dose-response relationship of HAVS in a tropical environment. A total of 173 male construction, forestry and automobile manufacturing plant workers in Malaysia were recruited into this study between August 2011 and 2012. The participants were interviewed for history of vibration exposure and HAVS symptoms, followed by hand functions evaluation and vibration measurement. Three types of vibration doses-lifetime vibration dose (LVD), total operating time (TOT) and cumulative exposure index (CEI)-were calculated and its log values were regressed against the symptoms of HAVS. The correlation between each vibration exposure dose and the hand function evaluation results was obtained. The adjusted prevalence ratio for finger tingling and numbness was 3.34 (95% CI 1.27 to 8.98) for subjects with lnLVD≥20 ln m(2) s(-4) against those <16 ln m(2) s(-4). Similar dose-response pattern was found for CEI but not for TOT. No subject reported white finger. The prevalence of finger coldness did not increase with any of the vibration doses. Vibrotactile perception thresholds correlated moderately with lnLVD and lnCEI. The dose-response relationship of HAVS in a tropical environment is valid for finger tingling and numbness. The LVD and CEI are more useful than TOT when evaluating the dose-response pattern of a heterogeneous group of vibratory tools workers.

  8. Monte Carlo assessment of computed tomography dose to tissue adjacent to the scanned volume.

    PubMed

    Boone, J M; Cooper, V N; Nemzek, W R; McGahan, J P; Seibert, J A

    2000-10-01

    The assessment of the radiation dose to internal organs or to an embryo or fetus is required on occasion for risk assessment or for comparing imaging studies. Limited resources hinder the ability to accurately assess the radiation dose received to locations outside the tissue volume actually scanned during computed tomography (CT). The purpose of this study was to assess peripheral doses and provide tabular data for dose evaluation. Validated Monte Carlo simulation techniques were used to compute the dose distribution along the length of water-equivalent cylindrical phantoms, 16 and 32 cm in diameter. For further validation, comparisons between physically measured and Monte Carlo-derived air kerma profiles were performed and showed excellent (1% to 2%) agreement. Polyenergetic x-ray spectra at 80, 100, 120, and 140 kVp with beam shaping filters were studied. Using 10(8) simulated photons input to the cylinders perpendicular to their long axis, line spread functions (LSF) of the dose distribution were determined at three depths in the cylinders (center, mid-depth, and surface). The LSF data were then used with appropriate mathematics to compute dose distributions along the long axis of the cylinder. The dose distributions resulting from helical (pitch = 1.0) scans and axial scans were approximately equivalent. Beyond about 3 cm from the edge of the CT scanned tissue volume, the fall-off of radiation dose was exponential. A series of tables normalized at 100 milliampere seconds (mAs) were produced which allow the straight-forward assessment of dose within and peripheral to the CT scanned volume. The tables should be useful for medical physicists and radiologists in the estimation of dose to sites beyond the edge of the CT scanned volume.

  9. TRANSPORTATION CASK RECEIPT AND RETURN FACILITY WORKER DOSE ASSESSMENT

    SciTech Connect

    V. Arakali

    2005-02-24

    The purpose of this design calculation is to estimate radiation doses received by personnel working in the Transportation Cask Receipt and Return Facility (TCRRF) of the repository including the personnel at the security gate and cask staging areas. This calculation is required to support the preclosure safety analysis (PCSA) to ensure that the predicted doses are within the regulatory limits prescribed by the U.S. Nuclear Regulatory Commission (NRC). The Cask Receipt and Return Facility receives NRC licensed transportation casks loaded with spent nuclear fuel (SNF) and high-level radioactive waste (HLW). The TCRRF operation starts with the receipt, inspection, and survey of the casks at the security gate and the staging areas, and proceeds to the process facilities. The transportation casks arrive at the site via rail cars or trucks under the guidance of the national transportation system. This calculation was developed by the Environmental and Nuclear Engineering organization and is intended solely for the use of Design and Engineering in work regarding facility design. Environmental and Nuclear Engineering personnel should be consulted before using this calculation for purposes other than those stated herein or for use by individuals other than authorized personnel in the Environmental and Nuclear Engineering organization.

  10. Assessment of effective dose to staff in brachytherapy.

    PubMed

    Faulkner, K; James, H V; Chapple, C L; Rawlings, D J

    1996-11-01

    The aim of this paper is to investigate the problem of monitoring effective dose to hospital staff who are involved in the treatment of tumors using sealed sources placed inside the body (brachytherapy). In addition, the use of an unsealed source to treat the thyroid was also considered. Radiation distributions produced by both sealed sources commonly used in brachytherapy (192I, 137Cs, 226Ra) and an unsealed source used in the treatment of the thyroid (131I) were used to irradiate a Rando phantom. The brachytherapy treatments of esophageal and gynecological carcinoma were simulated. The Rando phantom was loaded with lithium fluoride thermoluminescent dosimeters at positions corresponding to a number of radiosensitive organs. Film badges and electronic personal dosimeters were attached to the Rando phantom at various anatomical sites. The Rando phantom was positioned adjacent to the patient at an angle of 90 degrees to the longitudinal axis of the patient. Irradiations were performed with and without a portable lead screen used on the radiotherapy wards. Effective dose was estimated for each simulated radiotherapy treatment and compared with the personal monitor readings. The data were used as a basis for the provision of advice on the wearing of the film badge dosimeters and the design of portable lead screens. The data also permitted a comparison between the two types of dosimeter when used for personal monitoring in brachytherapy.

  11. Radiation dose assessment from ingestion pathway in Saudi Arabia

    SciTech Connect

    Abdul-Majid, S.; Abdul-Fattah, A.R.A.F.; Abulfaraj, W.H. )

    1992-01-01

    Levels of radioactivities in foodstuffs in the local market have been measured for the period from November 1987 until end of June 1988. Out of the 674 samples analyzed there were 83 milk powder, 85 infant milk powder, 54 infant cereals, 89 meat, 16 lentils, 14 wheat, and 26 macaroni samples. The average radioactivity concentration of {sup 137}Cs and {sup 134}Cs, in these samples in Bq/kg were 19, 13, 18, 6, 10, 25 and 13 respectively. The rest adults and infant foodstuffs had negligible radioactivity levels. The calculated annual doses from ingestion pathway due to {sup 137}Cs and {sup 134}Cs for adults were 3.13 {times} 10{sup {minus}5} Sv and 2.1 {times} 10{sup {minus}5} Sv while for one year old infant they were 12 {times} 10{sup {minus}5} Sv and 8 {times} 10{sup {minus}5} Sv respectively. The estimated accumulated dose for 50 years from {sup 90}Sr due to one year food ingestion for adults and one year old infants were 3.76 {times} 3.76 {times} 10{sup {minus}5} Sv and 5.2 {times} 10{sup {minus}5} Sv respectively.

  12. EMP Attachment 3 DOE-SC PNNL Site Dose Assessment Guidance

    SciTech Connect

    Snyder, Sandra F.

    2011-12-21

    This Dose Assessment Guidance (DAG) describes methods to use to determine the Maximally-Exposed Individual (MEI) location and to estimate dose impact to that individual under the U.S. Department of Energy Office of Science (DOE-SC) Pacific Northwest National Laboratory (PNNL) Site Environmental Monitoring Plan (EMP). This guidance applies to public dose from radioactive material releases to the air from PNNL Site operations. This document is an attachment to the Pacific Northwest National Laboratory (PNNL) Environmental Monitoring Plan (EMP) and describes dose assessment guidance for radiological air emissions. The impact of radiological air emissions from the U.S. Department of Energy Office of Science (DOE-SC) PNNL Site is indicated by dose estimates to a maximally exposed member of the public, referred to as the maximally exposed individual (MEI). Reporting requirements associated with dose to members of the public from radiological air emissions are in 40 CFR Part 61.94, WAC 246-247-080, and DOE Order 458.1. The DOE Order and state standards for dose from radioactive air emissions are consistent with U.S. Environmental Protection Agency (EPA) dose standards in 40 CFR 61.92 (i.e., 10 mrem/yr to a MEI). Despite the fact that the current Contract Requirements Document (CRD) for the DOE-SC PNNL Site operations does not include the requirement to meet DOE CRD 458.1, paragraph 2.b, public dose limits, the DOE dose limits would be met when EPA limits are met.

  13. Using the Monte Carlo method for assessing the tissue and organ doses of patients in dental radiography

    NASA Astrophysics Data System (ADS)

    Makarevich, K. O.; Minenko, V. F.; Verenich, K. A.; Kuten, S. A.

    2016-05-01

    This work is dedicated to modeling dental radiographic examinations to assess the absorbed doses of patients and effective doses. For simulating X-ray spectra, the TASMIP empirical model is used. Doses are assessed on the basis of the Monte Carlo method by using MCNP code for voxel phantoms of ICRP. The results of the assessment of doses to individual organs and effective doses for different types of dental examinations and features of X-ray tube are presented.

  14. Estimating Toxicity Pathway Activating Doses for High Throughput Chemical Risk Assessments

    EPA Science Inventory

    Estimating a Toxicity Pathway Activating Dose (TPAD) from in vitro assays as an analog to a reference dose (RfD) derived from in vivo toxicity tests would facilitate high throughput risk assessments of thousands of data-poor environmental chemicals. Estimating a TPAD requires def...

  15. Estimating Toxicity Pathway Activating Doses for High Throughput Chemical Risk Assessments

    EPA Science Inventory

    Estimating a Toxicity Pathway Activating Dose (TPAD) from in vitro assays as an analog to a reference dose (RfD) derived from in vivo toxicity tests would facilitate high throughput risk assessments of thousands of data-poor environmental chemicals. Estimating a TPAD requires def...

  16. A novel tool for assessing and summarizing the built environment

    PubMed Central

    2012-01-01

    Background A growing corpus of research focuses on assessing the quality of the local built environment and also examining the relationship between the built environment and health outcomes and indicators in communities. However, there is a lack of research presenting a highly resolved, systematic, and comprehensive spatial approach to assessing the built environment over a large geographic extent. In this paper, we contribute to the built environment literature by describing a tool used to assess the residential built environment at the tax parcel-level, as well as a methodology for summarizing the data into meaningful indices for linkages with health data. Methods A database containing residential built environment variables was constructed using the existing body of literature, as well as input from local community partners. During the summer of 2008, a team of trained assessors conducted an on-foot, curb-side assessment of approximately 17,000 tax parcels in Durham, North Carolina, evaluating the built environment on over 80 variables using handheld Global Positioning System (GPS) devices. The exercise was repeated again in the summer of 2011 over a larger geographic area that included roughly 30,700 tax parcels; summary data presented here are from the 2008 assessment. Results Built environment data were combined with Durham crime data and tax assessor data in order to construct seven built environment indices. These indices were aggregated to US Census blocks, as well as to primary adjacency communities (PACs) and secondary adjacency communities (SACs) which better described the larger neighborhood context experienced by local residents. Results were disseminated to community members, public health professionals, and government officials. Conclusions The assessment tool described is both easily-replicable and comprehensive in design. Furthermore, our construction of PACs and SACs introduces a novel concept to approximate varying scales of community and

  17. QUANTITATION OF MOLECULAR ENDPOINTS FOR THE DOSE-RESPONSE COMPONENT OF CANCER RISK ASSESSMENT

    EPA Science Inventory

    Cancer risk assessment involves the steps of hazard identification, dose-response assessment, exposure assessment and risk characterization. The rapid advances in the use of molecular biology approaches has had an impact on all four components, but the greatest overall current...

  18. QUANTITATION OF MOLECULAR ENDPOINTS FOR THE DOSE-RESPONSE COMPONENT OF CANCER RISK ASSESSMENT

    EPA Science Inventory

    Cancer risk assessment involves the steps of hazard identification, dose-response assessment, exposure assessment and risk characterization. The rapid advances in the use of molecular biology approaches has had an impact on all four components, but the greatest overall current...

  19. Strategic security management: risk assessments in the environment of care.

    PubMed

    Vellani, Karim H

    2006-01-01

    Securing the environment of care is a challenging and continuous effort for most healthcare security managers, who face unique challenges in balancing the open campus environment with the protection needs of the hospital's patients, employees, and other assets. By conducting a comprehensive risk assessment, hospital security managers can prioritize identified risks, develop an effective hospital security program, and reduce risk to a manageable and acceptable level. This article discusses a 5-step risk assessment process that enhances the hospital security program by effectively mitigating risks to the hospital.

  20. ASSESSING RESIDENTIAL EXPOSURE USING THE STOCHASTIC HUMAN EXPOSURE AND DOSE SIMULATION (SHEDS) MODEL

    EPA Science Inventory

    As part of a workshop sponsored by the Environmental Protection Agency's Office of Research and Development and Office of Pesticide Programs, the Aggregate Stochastic Human Exposure and Dose Simulation (SHEDS) Model was used to assess potential aggregate residential pesticide e...

  1. ASSESSING RESIDENTIAL EXPOSURE USING THE STOCHASTIC HUMAN EXPOSURE AND DOSE SIMULATION (SHEDS) MODEL

    EPA Science Inventory

    As part of a workshop sponsored by the Environmental Protection Agency's Office of Research and Development and Office of Pesticide Programs, the Aggregate Stochastic Human Exposure and Dose Simulation (SHEDS) Model was used to assess potential aggregate residential pesticide e...

  2. Spectrum-dose conversion operator of NaI(Tl) and CsI(Tl) scintillation detectors for air dose rate measurement in contaminated environments.

    PubMed

    Tsuda, Shuichi; Saito, Kimiaki

    2017-01-01

    Spectrum-dose conversion operators, the G(E) functions, for common NaI(Tl) scintillation survey meters and CsI(Tl) detectors are obtained for measurements in a semi-infinite plane of contaminated ground field by photon-emitting radionuclides (ground source). The calculated doses at a height of 100 cm from the ground in (137)Cs-contaminated environments by the Monte Carlo simulation technique are compared with those obtained using the G(E) functions by assuming idealized irradiation geometries such as anterior-posterior or isotropic. The simulation reveals that one could overestimate air dose rates in the environment by a maximum of 20-30% for NaI(Tl) detectors and 40-50% for CsI(Tl) detectors depending on photon energy when using the G(E) functions assuming idealized irradiation geometries for ground source measurements. Measurements obtained after the nuclear accident in Fukushima reveal that the doses calculated using a G(E) function for a unidirectional irradiation geometry are 1.17 times higher than those calculated using a G(E) function for the ground source in the case of a CsI(Tl) scintillation detector, which has a rectangular parallelepiped crystal (13 × 13 × 20 mm(3)). However, if a G(E) function is used assuming irradiation to a surface of the detector, the doses agree with those of the ground source within 2%. These results indicate that in contaminated environments, the commonly used scintillation-based detectors overestimate doses within the acceptable limit. In addition, the degree of overestimation depends on the irradiation direction of each detector assumed for developing the G(E) function. With regard to directional dependence of the detectors, reliable air dose rates in the environment can be obtained using the G(E) function determined in unidirectional irradiation geometry, provided that the irradiation surface of the crystal is determined properly.

  3. Assessment of gamma dose rates in air in Adana/Turkey.

    PubMed

    Degerlier, M; Ozger, G

    2008-01-01

    This study assesses the outdoor gamma absorbed dose levels in air of the Adana's region. The measurements were taken from 130 different sample points in this area by Eberline Smart Portable (ESP-2) with SPA-6 plastic scintillation detector. The outdoor gamma absorbed dose rates order from 40 to 145 nGy h(-1). Average outdoor gamma dose rates were measured as 65 nGy h(-1). Average effective dose received from outdoor gamma radiation in Adana's region is 80 microSv y(-1).

  4. Environment, Safety and Health Progress Assessment of the Hanford Site

    SciTech Connect

    Not Available

    1992-05-01

    This report documents the result of the US Department of Energy (DOE) Environment, Safety and Health (ES&H) Progress Assessment of the Hanford Site, in Richland, Washington. The assessment, which was conducted from May 11 through May 22, 1992, included a selective-review of the ES&H management systems and programs of the responsible DOE Headquarters Program Offices the DOE Richland Field Office, and the site contractors. The ES&H Progress Assessments are part of the Secretary of Energy`s continuing effort to institutionalize line management accountability and the self-assessment process throughout DOE and its contractor organizations. The purpose of the Hanford Site ES&H Progress Assessment is to provide the Secretary with an independent assessment of the adequacy and effectiveness of the DOE and contractor management structures, resources, and systems to address ES&H problems and requirements. They are not intended to be comprehensive compliance assessments of ES&H activities. The point of reference for assessing programs at the Hanford Site was, for the most part, the Tiger Team Assessment of the Hanford Site, which was conducted from May 21 through July 18, 1990. A summary of issues and progress in the areas of environment, safety and health, and management is included.

  5. Appropriate Use of Effective Dose in Radiation Protection and Risk Assessment.

    PubMed

    Fisher, Darrell R; Fahey, Frederic H

    2017-08-01

    Effective dose was introduced by the ICRP for the single, over-arching purpose of setting limits for radiation protection. Effective dose is a derived quantity or mathematical construct and not a physical, measurable quantity. The formula for calculating effective dose to a reference model incorporates terms to account for all radiation types, organ and tissue radiosensitivities, population groups, and multiple biological endpoints. The properties and appropriate applications of effective dose are not well understood by many within and outside the health physics profession; no other quantity in radiation protection has been more confusing or misunderstood. According to ICRP Publication 103, effective dose is to be used for "prospective dose assessment for planning and optimization in radiological protection, and retrospective demonstration of compliance for regulatory purposes." In practice, effective dose has been applied incorrectly to predict cancer risk among exposed persons. The concept of effective dose applies generally to reference models only and not to individual subjects. While conceived to represent a measure of cancer risk or heritable detrimental effects, effective dose is not predictive of future cancer risk. The formula for calculating effective dose incorporates committee-selected weighting factors for radiation quality and organ sensitivity; however, the organ weighting factors are averaged across all ages and both genders and thus do not apply to any specific individual or radiosensitive subpopulations such as children and young women. Further, it is not appropriate to apply effective dose to individual medical patients because patient-specific parameters may vary substantially from the assumptions used in generalized models. Also, effective dose is not applicable to therapeutic uses of radiation, as its mathematical underpinnings pertain only to observed late (stochastic) effects of radiation exposure and do not account for short-term adverse

  6. A comprehensive dose assessment of irradiated hand by iridium-192 source in industrial radiography.

    PubMed

    Hosseini Pooya, S M; Dashtipour, M R; Paydar, R; Mianji, F; Pourshahab, B

    2017-09-04

    Among the various incidents in industrial radiography, inadvertent handling of sources by hands is one of the most frequent incidents in which some parts of the hands may be locally exposed to high doses. An accurate assessment of extremity dose assists medical doctors in selecting appropriate treatments, preventing the injury expansion in the region. In this study, a phantom was designed to simulate a fisted hand of a radiographer when the worker holds a radioactive source in their hands. The local doses were measured using implanted TLDs in the phantom at different distances from a source. Furthermore, skin dose distribution was measured by Gaf-chromic films in the palm region of the phantom. The reliability of the measurements has been studied via analytical as well as Monte-Carlo simulation methods. The results showed that the new phantom design can be used reliably in extremity dose assessments, particularly at the points next to the source.

  7. Dosimetry experiences and lessons learned for radiation dose assessment in Korean nuclear power plants.

    PubMed

    Choi, Jong Rak; Kim, Hee Geun; Kong, Tae Young; Son, Jung Kwon

    2013-07-01

    Since the first Korean nuclear power plant (NPP), Kori 1, commenced operation in 1978, a total of 21 NPPs had been put into operation in Korea by the end of 2011. Radiation doses of NPP workers have been periodically evaluated and controlled within the prescribed dose limit. Radiation dose assessment is carried out monthly by reading personal dosemeters for external radiation exposure, which have traceability in compliance with strict technical guidelines. In the case of the internal radiation exposure, workers who have access to the possible area of polluted air are also evaluated for their internal dose after maintenance task. In this article, the overall situation and experience for the assessment and distribution of radiation doses in Korean NPPs is described.

  8. 4D cone beam CT-based dose assessment for SBRT lung cancer treatment

    NASA Astrophysics Data System (ADS)

    Cai, Weixing; Dhou, Salam; Cifter, Fulya; Myronakis, Marios; Hurwitz, Martina H.; Williams, Christopher L.; Berbeco, Ross I.; Seco, Joao; Lewis, John H.

    2016-01-01

    The purpose of this research is to develop a 4DCBCT-based dose assessment method for calculating actual delivered dose for patients with significant respiratory motion or anatomical changes during the course of SBRT. To address the limitation of 4DCT-based dose assessment, we propose to calculate the delivered dose using time-varying (‘fluoroscopic’) 3D patient images generated from a 4DCBCT-based motion model. The method includes four steps: (1) before each treatment, 4DCBCT data is acquired with the patient in treatment position, based on which a patient-specific motion model is created using a principal components analysis algorithm. (2) During treatment, 2D time-varying kV projection images are continuously acquired, from which time-varying ‘fluoroscopic’ 3D images of the patient are reconstructed using the motion model. (3) Lateral truncation artifacts are corrected using planning 4DCT images. (4) The 3D dose distribution is computed for each timepoint in the set of 3D fluoroscopic images, from which the total effective 3D delivered dose is calculated by accumulating deformed dose distributions. This approach is validated using six modified XCAT phantoms with lung tumors and different respiratory motions derived from patient data. The estimated doses are compared to that calculated using ground-truth XCAT phantoms. For each XCAT phantom, the calculated delivered tumor dose values generally follow the same trend as that of the ground truth and at most timepoints the difference is less than 5%. For the overall delivered dose, the normalized error of calculated 3D dose distribution is generally less than 3% and the tumor D95 error is less than 1.5%. XCAT phantom studies indicate the potential of the proposed method to accurately estimate 3D tumor dose distributions for SBRT lung treatment based on 4DCBCT imaging and motion modeling. Further research is necessary to investigate its performance for clinical patient data.

  9. Experimentally Assessing a Resource-Effective Design for ODL Environments

    ERIC Educational Resources Information Center

    Karoulis, Athanasis; Sfetsos, Panagiotis; Stamelos, Ioannis; Angelis, Lefteris; Pombortsis, Andreas

    2004-01-01

    This study is concerned with the formal assessment of a Distance Learning Environment (DLE) created to deliver a course on UML sequence diagrams to university-level students, divided into control and treatment groups. An ad-hoc DLE was constructed to deliver instruction to the treatment group, while the control group was taught in a traditional…

  10. Experimentally Assessing a Resource-Effective Design for ODL Environments

    ERIC Educational Resources Information Center

    Karoulis, Athanasis; Sfetsos, Panagiotis; Stamelos, Ioannis; Angelis, Lefteris; Pombortsis, Andreas

    2004-01-01

    This study is concerned with the formal assessment of a Distance Learning Environment (DLE) created to deliver a course on UML sequence diagrams to university-level students, divided into control and treatment groups. An ad-hoc DLE was constructed to deliver instruction to the treatment group, while the control group was taught in a traditional…

  11. Personnel Performance Assessment in Information Systems Outsourcing Environments

    ERIC Educational Resources Information Center

    Casado-Lumbreras, Cristina; Soto-Acosta, Pedro; Colomo-Palacios, Ricardo; de Pablos, Patricia Ordonez

    2011-01-01

    Purpose: The aim of this paper is to present a tool which uses semantic technologies for personnel performance and workplace learning assessment in outsourced information technology environments. Design/methodology/approach: The paper presents the tool from a technical perspective and introduces a use case that depicts the main features related to…

  12. An assessment of the common carrier shipping environment

    Treesearch

    F. E. Ostrem; W. D. Godshall

    1979-01-01

    An assessment of available data and information describing the common carrier shipping environment was conducted. The assesment included the major shipping hazards of shock, vibration, impact, temperature, and humidity associated with the handling, transportation, and warehousing operations of typical distribution cycles. Previous environmental studies and current data...

  13. Personnel Performance Assessment in Information Systems Outsourcing Environments

    ERIC Educational Resources Information Center

    Casado-Lumbreras, Cristina; Soto-Acosta, Pedro; Colomo-Palacios, Ricardo; de Pablos, Patricia Ordonez

    2011-01-01

    Purpose: The aim of this paper is to present a tool which uses semantic technologies for personnel performance and workplace learning assessment in outsourced information technology environments. Design/methodology/approach: The paper presents the tool from a technical perspective and introduces a use case that depicts the main features related to…

  14. Assessment of adequacy of hemodialysis dose at a Palestinian hospital.

    PubMed

    Adas, Heba; Al-Ramahi, Rowa; Jaradat, Nidal; Badran, Rand

    2014-03-01

    Adequacy of hemodialysis improves patient survival, quality of life and biochemical outcomes and minimizes disease complications and hospitalizations. This study was an observational cross-sectional study that was conducted in July 2012. Blood tests, weight and blood pressure were measured before and after hemodialysis. Single-pool Kt/V and urea reduction ratio (URR) were calculated. The targets based on the National Kidney Foundation Disease Outcomes Quality Initiative (KDOQI) Clinical Practice Guidelines were Kt/V ≥ 1.2 and URR ≥ 65%. Of the 64 patients, 41 (64.1%) were males. The mean age of the patients was 58.13 ± 17.2 years. The mean body mass index (BMI) was 25.04 ± 5.01 kg/m 2 . The mean Kt/V and URR were 1.06 ± 0.05 and 54.4 ± 19.3, respectively. There was no significant difference between men and women (1.06 ± 0.47 versus 1.04 ± 0.55, P = 0.863) and (54.7 ± 19.59 versus 53.81 ± 19.17, P = 0.296). Only 25 (39.1%) patients achieved the Kt/V goal and only 22 (34.4%) had target URR, and there was no significant association between hemodialysis adequacy and any of the variables such as sex, age, presence of chronic diseases or BMI. Serum potassium levels post-dialysis were significantly lower in patients who reached the target Kt/V (mean = 3.44 ± 0.48 versus 3.88 ± 0.48, P = 0.001). Most patients were inadequately dialyzed and a large percentage of the patients did not attain the targets. Attempts to achieve the desired goals are necessary. It is important to calculate Kt/V or URR and individualize the dialysis doses for each patient.

  15. Development of the Classroom Sensory Environment Assessment (CSEA).

    PubMed

    Kuhaneck, Heather Miller; Kelleher, Jaqueline

    2015-01-01

    The Classroom Sensory Environment Assessment (CSEA) is a tool that provides a means of understanding the impact of a classroom's sensory environment on student behavior. The purpose of the CSEA is to promote collaboration between occupational therapists and elementary education teachers. In particular, students with autism spectrum disorder included in general education classrooms may benefit from a suitable match created through this collaborative process between the sensory environment and their unique sensory preferences. The development of the CSEA has occurred in multiple stages over 2 yr. This article reports on descriptive results for 152 classrooms and initial reliability results. Descriptive information suggests that classrooms are environments with an enormous variety of sensory experiences that can be quantified. Visual experiences are most frequent. The tool has adequate internal consistency but requires further investigation of interrater reliability and validity.

  16. Assessment of space environment induced microdamage in toughened composite materials

    NASA Technical Reports Server (NTRS)

    Sykes, George F.; Funk, Joan G.; Slemp, Wayne S.

    1986-01-01

    The effects of simulated space environments on the microdamage in a series of commercially available toughened matrix composite systems was determined. Low-earth orbit (LEO) exposures were simulated by thermal cycling; geosynchronous orbit (GEO) exposures were simulated by electron irradiation plus thermal cycling. Material response was characterized by assessing the induced microcracking and its influence on chemical and mechanical property changes. All materials, including several advanced, tough thermoplastics microcracked when exposed to the simulated LEO environment except a 177 C cured single phase toughened epoxy composite. The GEO simulated environment produced microdamage in all materials. The results suggest that increased matrix toughness may not be the overriding factor leading to improved durability in the space environment.

  17. ANDROS: A code for Assessment of Nuclide Doses and Risks with Option Selection

    SciTech Connect

    Begovich, C.L.; Sjoreen, A.L.; Ohr, S.Y.; Chester, R.O.

    1986-11-01

    ANDROS (Assessment of Nuclide Doses and Risks with Option Selection) is a computer code written to compute doses and health effects from atmospheric releases of radionuclides. ANDROS has been designed as an integral part of the CRRIS (Computerized Radiological Risk Investigation System). ANDROS reads air concentrations and environmental concentrations of radionuclides to produce tables of specified doses and health effects to selected organs via selected pathways (e.g., ingestion or air immersion). The calculation may be done for an individual at a specific location or for the population of the whole assessment grid. The user may request tables of specific effects for every assessment grid location. Along with the radionuclide concentrations, the code requires radionuclide decay data, dose and risk factors, and location-specific data, all of which are available within the CRRIS. This document is a user manual for ANDROS and presents the methodology used in this code.

  18. Generation of dose-response relationships to assess the effects of acidity in precipitation on growth and productivity of vegetation

    SciTech Connect

    Evans, L.S.

    1981-01-01

    Experiments were performed with several plant species in natural environments as well in a greenhouse and/or tissue culture facilities to establish dose-response functions of plant responses to simulated acidic rain in order to determine environmental risk assessments to ambient levels of acidic rain. Response functions of foliar injury, biomass of leaves and seed of soybean and pinto beans, root yields of radishes and garden beets, and reproduction of bracken fern are considered. The dose-response function of soybean seed yields with the hydrogen ion concentration of simulated acidic rainfalls was expressed by the equation y = 21.06-1.01 log x where y = seed yield in grams per plant and x = the hydrogen concentration if ..mu..eq l/sup -1/. The correlation coefficient of this relationship was -0.90. A similar dose-response function was generated for percent fertilization of ferns in a forest understory. When percent fertilization is plotted on logarithmic scale with hydrogen ion concentration of the simulated rain solution, the Y intercept is 51.18, slope -0.041 with a correlation coefficient of -0.98. Other dose-response functions were generated that assist in a general knowledge as to which plant species and which physiological processes are most impacted by acidic precipitation. Some responses did not produce convenient dose-response relationships. In such cases the responses may be altered by other environmental factors or there may be no differences among treatment means.

  19. Radiological dose assessments at the Kennedy Space Center

    SciTech Connect

    Firstenberg, H.; Jubach, R.; Bartram, B.; Vaughan, F.

    1989-01-01

    This paper discusses the application of an atmospheric transport and diffusion model for launch window and safety risk assessment studies in support of the Galileo (which is scheduled for the October/November 1989 period) and Ulysses (scheduled for {approximately}1 yr after Galileo) missions at the Kennedy Space Center (KSC). The model is resident in the EMERGE software system developed by NUS Corporation and modified for the U.S. Department of Energy (DOE) to provide real-time and safety analyses report support for the launches. The application is unique in that the model accommodates the varied amount of meteorological data at KSC and Cape Canaveral and includes a site-specific algorithm to account for local-scale circulations. This paper focuses on the Galileo mission application, including discussions of the use of the meteorological data available at KSC, integration of the EMERGE sea-breeze algorithm, and examples of real-time and safety analyses report assessments. The Galileo spacecraft is to be launched toward Jupiter using the space shuttle.

  20. LANL Safety Conscious Work Environment (SCWE) Self-Assessment

    SciTech Connect

    Hargis, Barbara C.

    2014-01-29

    On December 21, 2012 Secretary of Energy Chu transmitted to the Defense Nuclear Facilities Safety Board (DNFSB) revised commitments on the implementation plan for Safety Culture at the Waste Treatment and Immobilization Plant. Action 2-5 was revised to require contractors and federal organizations to complete Safety Conscious Work Environment (SCWE) selfassessments and provide reports to the appropriate U.S. Department of Energy (DOE) - Headquarters Program Office by September 2013. Los Alamos National Laboratory (LANL) planned and conducted a Safety Conscious Work Environment (SCWE) Self-Assessment over the time period July through August, 2013 in accordance with the SCWE Self-Assessment Guidance provided by DOE. Significant field work was conducted over the 2-week period August 5-16, 2013. The purpose of the self-assessment was to evaluate whether programs and processes associated with a SCWE are in place and whether they are effective in supporting and promoting a SCWE.

  1. 3D-printed applicators for high dose rate brachytherapy: Dosimetric assessment at different infill percentage.

    PubMed

    Ricotti, Rosalinda; Vavassori, Andrea; Bazani, Alessia; Ciardo, Delia; Pansini, Floriana; Spoto, Ruggero; Sammarco, Vittorio; Cattani, Federica; Baroni, Guido; Orecchia, Roberto; Jereczek-Fossa, Barbara Alicja

    2016-12-01

    Dosimetric assessment of high dose rate (HDR) brachytherapy applicators, printed in 3D with acrylonitrile butadiene styrene (ABS) at different infill percentage. A low-cost, desktop, 3D printer (Hamlet 3DX100, Hamlet, Dublin, IE) was used for manufacturing simple HDR applicators, reproducing typical geometries in brachytherapy: cylindrical (common in vaginal treatment) and flat configurations (generally used to treat superficial lesions). Printer accuracy was investigated through physical measurements. The dosimetric consequences of varying the applicator's density by tuning the printing infill percentage were analysed experimentally by measuring depth dose profiles and superficial dose distribution with Gafchromic EBT3 films (International Specialty Products, Wayne, NJ). Dose distributions were compared to those obtained with a commercial superficial applicator. Measured printing accuracy was within 0.5mm. Dose attenuation was not sensitive to the density of the material. Surface dose distribution comparison of the 3D printed flat applicators with respect to the commercial superficial applicator showed an overall passing rate greater than 94% for gamma analysis with 3% dose difference criteria, 3mm distance-to-agreement criteria and 10% dose threshold. Low-cost 3D printers are a promising solution for the customization of the HDR brachytherapy applicators. However, further assessment of 3D printing techniques and regulatory materials approval are required for clinical application. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  2. Effect of radiocesium transfer on ambient dose rate in forest environments affected by the Fukushima Nuclear Power Plant accident

    NASA Astrophysics Data System (ADS)

    Kato, H.

    2015-12-01

    We investigated the transfer of canopy-intercepted radiocesium to the forest floor during 3 years following the Fukushima Daiichi Nuclear Power Plant accident. The cesium-137 (Cs-137) contents in throughfall, stemflow, and litterfall were monitored in two coniferous stands (plantation of Japanese cedar) and a deciduous broad-leaved forest stand (Japanese oak with red pine). We also measured the ambient dose rate (ADR) at different heights in the forest using a survey meter and a portable Ge gamma-ray detector. Total Cs-137 deposition flux from the canopy to forest floor for the mature cedar, young cedar, and the mixed broad-leaved stands were 166 kBq/m2, 174 kBq/m2, and 60 kBq/m2, respectively. These values correspond to 38%, 40% and 13% of total atmospheric input after the accident. The ambient dose rate in forest exhibited height dependency and its vertical distribution varied with forest type and stand age. The ambient dose rate showed an exponential decrease with time for all the forest sites, however the decreasing trend differed depending on the height of dose measurement and forest type. The ambient dose rate at the canopy (approx. 10 m-height) decreased faster than that expected from physical decay of the two radiocesium isotopes, whereas those at the forest floor varied between the three forest stands. The radiocesium deposition via throughfall seemed to increase ambient dose rate during the first 200 days after the accident, however there was no clear relationship between litterfall and ambient dose rate since 400 days after the accident. These data suggested that the ambient dose rate in forest environment varied both spatially and temporally reflecting the transfer of radiocesium from canopy to forest floor. However, further monitoring investigation and analysis are required to determine the effect of litterfall on long-term trend of ambient dose rate in forest environments.

  3. Displaying 3D radiation dose on endoscopic video for therapeutic assessment and surgical guidance

    NASA Astrophysics Data System (ADS)

    Qiu, Jimmy; Hope, Andrew J.; Cho, B. C. John; Sharpe, Michael B.; Dickie, Colleen I.; DaCosta, Ralph S.; Jaffray, David A.; Weersink, Robert A.

    2012-10-01

    We have developed a method to register and display 3D parametric data, in particular radiation dose, on two-dimensional endoscopic images. This registration of radiation dose to endoscopic or optical imaging may be valuable in assessment of normal tissue response to radiation, and visualization of radiated tissues in patients receiving post-radiation surgery. Electromagnetic sensors embedded in a flexible endoscope were used to track the position and orientation of the endoscope allowing registration of 2D endoscopic images to CT volumetric images and radiation doses planned with respect to these images. A surface was rendered from the CT image based on the air/tissue threshold, creating a virtual endoscopic view analogous to the real endoscopic view. Radiation dose at the surface or at known depth below the surface was assigned to each segment of the virtual surface. Dose could be displayed as either a colorwash on this surface or surface isodose lines. By assigning transparency levels to each surface segment based on dose or isoline location, the virtual dose display was overlaid onto the real endoscope image. Spatial accuracy of the dose display was tested using a cylindrical phantom with a treatment plan created for the phantom that matched dose levels with grid lines on the phantom surface. The accuracy of the dose display in these phantoms was 0.8-0.99 mm. To demonstrate clinical feasibility of this approach, the dose display was also tested on clinical data of a patient with laryngeal cancer treated with radiation therapy, with estimated display accuracy of ˜2-3 mm. The utility of the dose display for registration of radiation dose information to the surgical field was further demonstrated in a mock sarcoma case using a leg phantom. With direct overlay of radiation dose on endoscopic imaging, tissue toxicities and tumor response in endoluminal organs can be directly correlated with the actual tissue dose, offering a more nuanced assessment of normal tissue

  4. Displaying 3D radiation dose on endoscopic video for therapeutic assessment and surgical guidance.

    PubMed

    Qiu, Jimmy; Hope, Andrew J; Cho, B C John; Sharpe, Michael B; Dickie, Colleen I; DaCosta, Ralph S; Jaffray, David A; Weersink, Robert A

    2012-10-21

    We have developed a method to register and display 3D parametric data, in particular radiation dose, on two-dimensional endoscopic images. This registration of radiation dose to endoscopic or optical imaging may be valuable in assessment of normal tissue response to radiation, and visualization of radiated tissues in patients receiving post-radiation surgery. Electromagnetic sensors embedded in a flexible endoscope were used to track the position and orientation of the endoscope allowing registration of 2D endoscopic images to CT volumetric images and radiation doses planned with respect to these images. A surface was rendered from the CT image based on the air/tissue threshold, creating a virtual endoscopic view analogous to the real endoscopic view. Radiation dose at the surface or at known depth below the surface was assigned to each segment of the virtual surface. Dose could be displayed as either a colorwash on this surface or surface isodose lines. By assigning transparency levels to each surface segment based on dose or isoline location, the virtual dose display was overlaid onto the real endoscope image. Spatial accuracy of the dose display was tested using a cylindrical phantom with a treatment plan created for the phantom that matched dose levels with grid lines on the phantom surface. The accuracy of the dose display in these phantoms was 0.8-0.99 mm. To demonstrate clinical feasibility of this approach, the dose display was also tested on clinical data of a patient with laryngeal cancer treated with radiation therapy, with estimated display accuracy of ∼2-3 mm. The utility of the dose display for registration of radiation dose information to the surgical field was further demonstrated in a mock sarcoma case using a leg phantom. With direct overlay of radiation dose on endoscopic imaging, tissue toxicities and tumor response in endoluminal organs can be directly correlated with the actual tissue dose, offering a more nuanced assessment of normal tissue

  5. External induced contamination environment assessment for Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Leger, Lubert; Ehlers, Horst; Hakes, Charles; Theall, Jeff; Soares, Carlos

    1993-01-01

    An assessment of the Space Station Freedom performance as affected by the external induced contamination environment is in progress. The assessment procedure involves comparing the Space Station Freedom external contamination requirements, SSP 30426, Revision B (1991), with calculated molecular deposition, molecular column density, and other effects from potential sources of contamination. The current assessment comprises discussions of Space Shuttle proximity operations, Space Shuttle waste-water dumps (while docked to the Space Station), Space Station fluid and waste-gas venting, system gas leakage, external material outgassing, and a combined contamination assessment. This performance assessment indicates that Space Station Freedom contamination requirements are realistic and can be satisfied when all contamination sources are included.

  6. External induced contamination environment assessment for Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Leger, Lubert; Ehlers, Horst; Hakes, Charles; Theall, Jeff; Soares, Carlos

    1993-01-01

    An assessment of the Space Station Freedom performance as affected by the external induced contamination environment is in progress. The assessment procedure involves comparing the Space Station Freedom external contamination requirements, SSP 30426, Revision B (1991), with calculated molecular deposition, molecular column density, and other effects from potential sources of contamination. The current assessment comprises discussions of Space Shuttle proximity operations, Space Shuttle waste-water dumps (while docked to the Space Station), Space Station fluid and waste-gas venting, system gas leakage, external material outgassing, and a combined contamination assessment. This performance assessment indicates that Space Station Freedom contamination requirements are realistic and can be satisfied when all contamination sources are included.

  7. Effective dose assessment for participants in the National Lung Screening Trial undergoing posteroanterior chest radiographic examinations.

    PubMed

    Kruger, Randell; Flynn, Michael J; Judy, Phillip F; Cagnon, Christopher H; Seibert, J Anthony

    2013-07-01

    The National Lung Screening Trial (NLST) is a multicenter randomized controlled trial comparing low-dose helical CT with chest radiography in the screening of older current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004, when 53,454 participants had been randomized at 33 screening sites. The objective of this study was to determine the effective radiation dose associated with individual chest radiographic screening examinations. A total of 73,733 chest radiographic examinations were performed with 92 chest imaging systems. The entrance skin air kerma (ESAK) of participants' chest radiographic examinations was estimated and used in this analysis. The effective dose per ESAK for each examination was determined with a Monte Carlo-based program. The examination effective dose was calculated as the product of the examination ESAK and the Monte Carlo estimate of the ratio of effective dose per ESAK. This study showed that the mean effective dose assessed from 66,157 postero-anterior chest examinations was 0.052 mSv. Additional findings were a median effective dose of 0.038 mSv, a 95th percentile value of 0.136 mSv, and a fifth percentile value of 0.013 mSv. The effective dose for participant NLST chest radiographic examinations was determined and is of specific interest in relation to that associated with the previously published NLST low-dose CT examinations conducted during the trial.

  8. Assessment of the radiological impact of gamma and radon dose rates at former U mining sites in Tajikistan.

    PubMed

    Lespukh, E; Stegnar, P; Yunusov, M; Tilloboev, H; Zyazev, G; Kayukov, P; Hosseini, A; Strømman, G; Salbu, B

    2013-12-01

    An assessment of the radiological situation due to exposure to gamma radiation, radon ((222)Rn) and thoron ((220)Rn) was carried out at former uranium (U) mining and processing sites in Taboshar and at Digmai in Tajikistan. Gamma dose rate measurements were made using various field instruments. (222)Rn/(220)Rn measurements were carried out with field instruments for instantaneous measurements and then discriminative (222)Rn/(220)Rn solid state nuclear track detectors (SSNTD) were used for longer representative measurements. The detectors were exposed for an extended period of time in different outdoor and indoor public and residential environments at the selected U legacy sites. The results showed that gamma, (222)Rn and (220)Rn doses were in general low, which consequently implies a low to relatively low radiological risk. The radiation doses deriving from external radiation (gamma dose rate), indoor (222)Rn and (220)Rn with their short-lived progenies did not exceed national or international standards. At none of the sites investigated did the average individual annual effective doses exceed 10 mSv, the recommended threshold value for the general public. A radiation hazard could be associated with exceptional situations, such as elevated exposures to ionizing radiation at the Digmai tailings site and/or in industrial facilities, where gamma and (222)Rn/(220)Rn dose rates could reach values of several 10 mSv/a. Current doses of ionizing radiation do not represent a hazard to the health of the resident public, with the exception of some specific situations. These issues should be adequately addressed to further reduce needless exposure of the resident public to ionizing radiation.

  9. Radioactive contamination in the Arctic--sources, dose assessment and potential risks.

    PubMed

    Strand, P; Howard, B J; Aarkrog, A; Balonov, M; Tsaturov, Y; Bewers, J M; Salo, A; Sickel, M; Bergman, R; Rissanen, K

    2002-01-01

    Arctic residents, whose diets comprise a large proportion of traditional terrestrial and freshwater foodstuffs, have received the highest radiation exposures to artificial radionuclides in the Arctic. Doses to members of both the average population and selected indigenous population groups in the Arctic depend on the rates of consumption of locally-derived terrestrial and freshwater foodstuffs, including reindeer/caribou meat, freshwater fish, goat cheese, berries, mushrooms and lamb. The vulnerability of arctic populations, especially indigenous peoples, to radiocaesium deposition is much greater than for temperate populations due to the importance of terrestrial, semi-natural exposure pathways where there is high radiocaesium transfer and a long ecological half-life for this radionuclide. In contrast, arctic residents with diets largely comprising marine foodstuffs have received comparatively low radiation exposures because of the lower levels of contamination of marine organisms. Using arctic-specific information, the predicted collective dose is five times higher than that estimated by UNSCEAR for temperate areas. The greatest threats to human health and the environment posed by human and industrial activities in the Arctic are associated with the potential for accidents in the civilian and military nuclear sectors. Of most concern are the consequences of potential accidents in nuclear power plant reactors, during the handling and storage of nuclear weapons, in the decommissioning of nuclear submarines and in the disposal of spent nuclear fuel from vessels. It is important to foster a close association between risk assessment and practical programmes for the purposes of improving monitoring, formulating response strategies and implementing action plans.

  10. Dose assessment intercomparisons within the RENEB network using G0-lymphocyte prematurely condensed chromosomes (PCC assay).

    PubMed

    Terzoudi, Georgia I; Pantelias, Gabriel; Darroudi, Firouz; Barszczewska, Katarzyna; Buraczewska, Iwona; Depuydt, Julie; Georgieva, Dimka; Hadjidekova, Valeria; Hatzi, Vasiliki I; Karachristou, Ioanna; Karakosta, Maria; Meschini, Roberta; M'Kacher, Radhia; Montoro, Alegria; Palitti, Fabrizio; Pantelias, Antonio; Pepe, Gaetano; Ricoul, Michelle; Sabatier, Laure; Sebastià, Natividad; Sommer, Sylwester; Vral, Anne; Zafiropoulos, Demetre; Wojcik, Andrzej

    2017-01-01

    Dose assessment intercomparisons within the RENEB network were performed for triage biodosimetry analyzing G0-lymphocyte PCC for harmonization, standardization and optimization of the PCC assay. Comparative analysis among different partners for dose assessment included shipment of PCC-slides and captured images to construct dose-response curves for up to 6 Gy γ-rays. Accident simulation exercises were performed to assess the suitability of the PCC assay by detecting speed of analysis and minimum number of cells required for categorization of potentially exposed individuals. Calibration data based on Giemsa-stained fragments in excess of 46 PCC were obtained by different partners using galleries of PCC images for each dose-point. Mean values derived from all scores yielded a linear dose-response with approximately 4 excess-fragments/cell/Gy. To unify scoring criteria, exercises were carried out using coded PCC-slides and/or coded irradiated blood samples. Analysis of samples received 24 h post-exposure was successfully performed using Giemsa staining (1 excess-fragment/cell/Gy) or centromere/telomere FISH-staining for dicentrics. Dose assessments by RENEB partners using appropriate calibration curves were mostly in good agreement. The PCC assay is quick and reliable for whole- or partial-body triage biodosimetry by scoring excess-fragments or dicentrics in G0-lymphocytes. Particularly, analysis of Giemsa-stained excess PCC-fragments is simple, inexpensive and its automation could increase throughput and scoring objectivity of the PCC assay.

  11. Assessment of a human computer interface prototyping environment

    NASA Technical Reports Server (NTRS)

    Moore, Loretta A.

    1993-01-01

    A Human Computer Interface (HCI) prototyping environment with embedded evaluation capability has been successfully assessed which will be valuable in developing and refining HCI standards and evaluating program/project interface development, especially Space Station Freedom on-board displays for payload operations. The HCI prototyping environment is designed to include four components: (1) a HCI format development tool, (2) a test and evaluation simulator development tool, (3) a dynamic, interactive interface between the HCI prototype and simulator, and (4) an embedded evaluation capability to evaluate the adequacy of an HCI based on a user's performance.

  12. Digital temperature sensor performance assessment report. [in simulated shuttle environments

    NASA Technical Reports Server (NTRS)

    Canniff, J. H.

    1974-01-01

    Performance assessment data accumulated during exposure of the digital temperature sensor to simulated shuttle flight type environments are presented. The test parameters were specifically designed to check the sensor for its: (1) ability to resolve temperature relative to the design specifications; (2) ability to maintain accuracy after interchanging the temperature probes with each electronics interface assembly; (3) stability (i.e., satisfactory operation and accuracy during and after exposure to flight environments); and (4) repeatability, or its ability to produce the same output on subsequent exposures to the identical stimulus. Equipment list, test descriptions, data summary, and conclusions are included.

  13. In Vitro Partial-Body Dose Assessment Using a Radiation Responsive Protein Biomarker

    DTIC Science & Technology

    2005-01-01

    partial - body ionizing radiation exposure . The radiation responsive protein biomarker studied was Growth Arrest DNA-Damage... radiation responsive protein bioassay to assess partial - body exposures in a murine in vivo validation, 23 These projects would offer a... REPORT TYPE 3. DATES COVERED - 4. TITLE AND SUBTITLE In Vitro Partial - Body Dose Assessment Using a Radiation Responsive Protein Biomarker

  14. Biochemical markers for the assessment of aquatic environment contamination

    PubMed Central

    Havelková, Marcela; Randák, Tomáš; Blahová, Jana; Slatinská, Iveta; Svobodová, Zdeňka

    2008-01-01

    The need for assessment of aquatic ecosystem contamination and of its impact on water dwelling organisms was developed in response to rising aquatic environmental pollution. In this field study, liver enzymes of phase I and phase II of xenobiotic transformation, namely cytochrome P450, ethoxyresorufin-O-deethylase, glutathione-S-transferase and tripeptide glutathione were used to assess the contamination of the aquatic environment at different rivers in the Czech Republic. The indicator species selected was the male chub (Leuciscus cephalus L.) and male brown trout (Salmo trutta fario). Chemical analyses included also the assessment of the most important inductors of previously mentioned biochemical markers. The major inductors of monitored biomarkers are industrial contaminants which belong to a large group of organic pollutants (PCB, PAH, PCDD/F, DDT, HCH, HCB and OCS), persistent in the environment. Four different groups of river basins were assessed: the River Tichá Orlice and its tributary the Kralický brook; important tributaries of the River Elbe (the rivers Orlice, Chrudimka, Cidlina, Jizera, Vltava, Ohře and Bílina); major rivers in the Czech Republic (the rivers Lužnice, Otava, Sázava, Berounka, Vltava, Labe, Ohře, Svratka, Dyje, Morava and Odra) and the River Vltava. The use of the biochemical markers together with chemical analyses seems to be an effective way to monitor the quality of aquatic environment. PMID:21218108

  15. Thermal environment assessment reliability using temperature--humidity indices.

    PubMed

    d'Ambrosio Alfano, Francesca Romana; Palella, Boris Igor; Riccio, Giuseppe

    2011-01-01

    A reliable assessment of the thermal environment should take into account the whole of the six parameters affecting the thermal sensation (air temperature, air velocity, humidity, mean radiant temperature, metabolic rate and thermo-physical properties of clothing). Anyway, the need of a quick evaluation based on few measurements and calculations has leaded to like best temperature-humidity indices instead of rational methods based on the heat balance on the human body. Among these, Canadian Humidex, preliminarily used only for weather forecasts, is becoming more and more widespread for a generalized assessment of both outdoor and indoor thermal environments. This custom arouses great controversies since using an index validated in outdoor conditions does not assure its indoor reliability. Moreover is it really possible to carry out the thermal environment assessment ignoring some of variables involved in the physiological response of the human body? Aiming to give a clear answer to these questions, this paper deals with a comparison between the assessment carried out according to the rational methods suggested by International Standards in force and the Humidex index. This combined analysis under hot stress situations (indoor and outdoor) has been preliminarily carried out; in a second phase the study deals with the indoor comfort prediction. Obtained results show that Humidex index very often leads to the underestimation of the workplace dangerousness and a poor reliability of comfort prediction when it is used in indoor situations.

  16. Development of an assessment of functioning scale for prison environments.

    PubMed

    Shelton, Deborah; Wakai, Sara

    2015-01-01

    This paper reports the development of a global assessment of functioning (GAF), modified from the DSM Axis V GAF for the prison environment. Focus groups, which were conducted with 36 correctional officers and clinicians in two prisons, provided descriptions of behavior in prison settings to re-align the GAF scale. Face validity was established. It was found that Habitation/Behavior, Social, and Symptoms emerged as important domains of functioning in prison. Gender differences were noted with regard to cleanliness, relationships and coping strategies. The cut-off score was identified at a score where offenders were unable to participate in a disciplinary process due to their mental illness. The structure of prison alters human functioning, requiring different assessment language and ratings to measure perceived behavioral norms and/or expectations. Front-line staff need the ability to observe and communicate behavioral changes quickly and accurately in a prison environment without undue burden upon their workload. This assessment was modified by front-line staff specifically for the prison environment to document quick and frequent assessments of observed changes over time in the offender population.

  17. A method for independent modelling in support of regulatory review of dose assessments.

    PubMed

    Dverstorp, Björn; Xu, Shulan

    2017-03-22

    Several countries consider geological disposal facilities as the preferred option for spent nuclear fuel due to their potential to provide isolation from the surface environment on very long timescales. In 2011 the Swedish Nuclear Fuel & Waste Management Co. (SKB) submitted a license application for construction of a spent nuclear fuel repository. The disposal method involves disposing spent fuel in copper canisters with a cast iron insert at about 500 m depth in crystalline basement rock, and each canister is surrounded by a buffer of swelling bentonite clay. SKB's license application is supported by a post-closure safety assessment, SR-Site. SR-Site has been reviewed by the Swedish Radiation Safety Authority (SSM) for five years. The main method for review of SKB's license application is document review, which is carried out by SSM's staff and supported by SSM's external experts. The review has proven a challenging task due to its broad scope, complexity and multidisciplinary nature. SSM and its predecessors have, for several decades, been developing independent models to support regulatory reviews of post-closure safety assessments for geological repositories. For the review of SR-Site, SSM has developed a modelling approach with a structured application of independent modelling activities, including replication modelling, use of alternative conceptual models and bounding calculations, to complement the traditional document review. This paper describes this scheme and its application to biosphere and dose assessment modelling. SSM's independent modelling has provided important insights regarding quality and reasonableness of SKB's rather complex biosphere modelling and has helped quantifying conservatisms and highlighting conceptual uncertainty.

  18. Analysis of Data from a System of Assessment of the Gonadal Radiation Dose During Radiographic Procedures

    PubMed Central

    Duggan, H. E.; Olde, G. L.

    1965-01-01

    The radiation hazard, if any, from diagnostic x-ray examinations was assessed in a study divided into three phases: (1) the gathering of data to allow estimation of the total gonadal dose received by each patient; (2) the accumulation of the individual and accumulative gonadal-dose totals on a large group of patients; (3) the examination and follow-up of patients who had received a substantial gonadal dose to determine any relationship between small recurring doses of ionizing radiation and various indices of somatic and genetic damage. The mean gonadal dose received by females was much higher than that received by males—1012 mr. as compared to 310 mr. Of 7021 individuals in this study, only 428 (6.1%) received 2 r. or more during the three-year test period. No definite conclusions as to radiation hazard could be made. A system, however, has been developed which, if continued, could eventually produce this basic information. PMID:14281086

  19. Three-year monitoring study of radiocesium transfer and ambient dose rate in forest environments affected by the Fukushima Dai-ichi Nuclear Power Plant accident

    NASA Astrophysics Data System (ADS)

    Kato, Hiroaki; Onda, Yuichi; Loffredo, Nicolas; Kawamori, Ayumi; Hisadome, Keigo

    2015-04-01

    We investigated the transfer of canopy-intercepted radiocesium to the forest floor during 3 years (July 2011~) following the Fukushima Dai-ichi Nuclear Power Plant accident. The cesium-137 (Cs-137) contents of throughfall, stemflow, and litterfall were monitored in two coniferous stands (plantation of Japanese cedar) and a deciduous broad-leaved forest stand (Japanese oak with red pine). We also measured an ambient dose rate at different height in the forest by using a survey meter (TCS-172B, Hitachi-Aloka Medical, LTD.) and a portable Ge gamma-ray detector (Detective-DX-100T, Ortec, Ametek, Inc.). Furthermore, effects of forest decontamination on the reduction of ambient dose rate were assessed quantitatively. Total Cs-137 deposition flux from the canopy to forest floor for the mature cedar, young cedar, and the mixed broad-leaved stands were 157 kBq/m^2, 167 kBq/m^2, and 54 kBq/m^2, respectively. These values correspond to 36%, 39% and 12% of total atmospheric input after the accident. The ambient dose rate showed an exponential decrease with time for all the forest sites, however the decreasing trend differed depending on the forest type. These data suggested that an ambient dose rate in forest environment can be variable in spatially and temporally reflecting the transfer of radiocesium from canopy to forest floor. We presented the analysis results of the relationship between radiocesium deposition flux and ambient dose rate at the forest floor. In addition to that, we reported the effects of forest decontamination (e.g., tree felling, removal of organic materials, woodchip pavement) on the reduction of ambient dose rate in the forest environment.

  20. Objective assessment of image quality and dose reduction in CT iterative reconstruction

    SciTech Connect

    Vaishnav, J. Y. Jung, W. C.; Popescu, L. M.; Zeng, R.; Myers, K. J.

    2014-07-15

    Purpose: Iterative reconstruction (IR) algorithms have the potential to reduce radiation dose in CT diagnostic imaging. As these algorithms become available on the market, a standardizable method of quantifying the dose reduction that a particular IR method can achieve would be valuable. Such a method would assist manufacturers in making promotional claims about dose reduction, buyers in comparing different devices, physicists in independently validating the claims, and the United States Food and Drug Administration in regulating the labeling of CT devices. However, the nonlinear nature of commercially available IR algorithms poses challenges to objectively assessing image quality, a necessary step in establishing the amount of dose reduction that a given IR algorithm can achieve without compromising that image quality. This review paper seeks to consolidate information relevant to objectively assessing the quality of CT IR images, and thereby measuring the level of dose reduction that a given IR algorithm can achieve. Methods: The authors discuss task-based methods for assessing the quality of CT IR images and evaluating dose reduction. Results: The authors explain and review recent literature on signal detection and localization tasks in CT IR image quality assessment, the design of an appropriate phantom for these tasks, possible choices of observers (including human and model observers), and methods of evaluating observer performance. Conclusions: Standardizing the measurement of dose reduction is a problem of broad interest to the CT community and to public health. A necessary step in the process is the objective assessment of CT image quality, for which various task-based methods may be suitable. This paper attempts to consolidate recent literature that is relevant to the development and implementation of task-based methods for the assessment of CT IR image quality.

  1. Identification and dose assessment of irradiated cardamom and cloves by EPR spectrometry

    NASA Astrophysics Data System (ADS)

    Beshir, W. B.

    2014-03-01

    The use of electron paramagnetic resonance spectroscopy to accurately distinguish irradiated from unirradiated cardamom and cloves and assesses the absorbed dose to radiation processed cardamom and cloves are examined. The results were successful for identifying both irradiated and unirradiated cardamom and cloves. Additive reirradiation of cardamom and cloves produces reproducible dose-response functions, which can be used to assess the initial dose by back-extrapolation. Third degree polynomial function was used to fit the EPR signal/dose curves. It was found that this 3rd degree polynomial function provides satisfactory results without correction of decay for free radicals. The stability of the radiation induced EPR signal of irradiated cardamom and cloves were studied over a storage period of almost 8 months.

  2. Qualitative and quantitative approaches in the dose-response assessment of genotoxic carcinogens.

    PubMed

    Fukushima, Shoji; Gi, Min; Kakehashi, Anna; Wanibuchi, Hideki; Matsumoto, Michiharu

    2016-05-01

    Qualitative and quantitative approaches are important issues in field of carcinogenic risk assessment of the genotoxic carcinogens. Herein, we provide quantitative data on low-dose hepatocarcinogenicity studies for three genotoxic hepatocarcinogens: 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and N-nitrosodiethylamine (DEN). Hepatocarcinogenicity was examined by quantitative analysis of glutathione S-transferase placental form (GST-P) positive foci, which are the preneoplastic lesions in rat hepatocarcinogenesis and the endpoint carcinogenic marker in the rat liver medium-term carcinogenicity bioassay. We also examined DNA damage and gene mutations which occurred through the initiation stage of carcinogenesis. For the establishment of points of departure (PoD) from which the cancer-related risk can be estimated, we analyzed the above events by quantitative no-observed-effect level and benchmark dose approaches. MeIQx at low doses induced formation of DNA-MeIQx adducts; somewhat higher doses caused elevation of 8-hydroxy-2'-deoxyquanosine levels; at still higher doses gene mutations occurred; and the highest dose induced formation of GST-P positive foci. These data indicate that early genotoxic events in the pathway to carcinogenesis showed the expected trend of lower PoDs for earlier events in the carcinogenic process. Similarly, only the highest dose of IQ caused an increase in the number of GST-P positive foci in the liver, while IQ-DNA adduct formation was observed with low doses. Moreover, treatment with DEN at low doses had no effect on development of GST-P positive foci in the liver. These data on PoDs for the markers contribute to understand whether genotoxic carcinogens have a threshold for their carcinogenicity. The most appropriate approach to use in low dose-response assessment must be approved on the basis of scientific judgment.

  3. Radiological dose assessment related to management of naturally occurring radioactive materials generated by the petroleum industry

    SciTech Connect

    Smith, K.P.; Blunt, D.L.; Williams, G.P.; Tebes, C.L.

    1996-09-01

    A preliminary radiological dose assessment of equipment decontamination, subsurface disposal, landspreading, equipment smelting, and equipment burial was conducted to address concerns regarding the presence of naturally occurring radioactive materials (NORM) in production waste streams. The assessment estimated maximum individual dose equivalents for workers and the general public. Sensitivity analyses of certain input parameters also were conducted. On the basis of this assessment, it is concluded that (1) regulations requiring workers to wear respiratory protection during equipment cleaning operations are likely to result in lower worker doses, (2) underground injection and downhole encapsulation of NORM wastes present a negligible risk to the general public, and (3) potential doses to workers and the general public related to smelting NORM-contaminated equipment can be controlled by limiting the contamination level of the initial feed. It is recommended that (1) NORM wastes be further characterized to improve studies of potential radiological doses; (2) states be encouraged to permit subsurface disposal of NORM more readily, provided further assessments support this study; results; (3) further assessment of landspreading NORM wastes be conducted; and (4) the political, economic, sociological, and nonradiological issues related to smelting NORM-contaminated equipment be studied to fully examine the feasibility of this disposal option.

  4. Variations in semiconductor device response in a medium-energy x-ray dose-enhancing environment

    SciTech Connect

    Beutler, D.E.; Fleetwood, D.M.; Beezhold, W.; Knott, D.; Lorence, L.J. Jr.; Draper, B.L.

    1987-01-01

    A series of experiments was performed to investigate the response of semiconductor devices to medium-energy x-ray irradiation under conditions in which dose-enhancement effects are very important. The response of MOS capacitors to ''dose-enhanced'' radiation can depend on incident radiation spectra, temperature of the device, and oxide electric field. Indeed, the amount of enhanced response can vary by as much as a factor of 10 as these conditions are changed. In such cases, it appears that changes in electron-hole recombination and hole trapping as a function of radiation energy are very important to the interpretation of the results. Therefore, coupled electron/photon transport codes such as the Monte Carlo integrated TIGER series (ITS), which consider only changes in the dose deposited in the device active region, are inadequate, at least in some cases, for predictions of dose-enhancement effects in semiconductor devices. In addition, the response of semiconductor diodes to dose-enhanced radiation appears to be qualitatively different from that of capacitors, and differs markedly in value from code predictions. Hence, an understanding of the modification of incident radiation by its interactions with dose-enhancing materials alone is insufficient to predict the response of semiconductor devices. The dependence of the device response on radiation spectra, electron-hole recombination, and hole transport and trapping, must also be included to assure good simulation fidelity of tests for devices to be used in dose-enhancing environments.

  5. Assessment of Southern California environment from ERTS-1

    NASA Technical Reports Server (NTRS)

    Bowden, L. W.; Viellenave, J. H.

    1973-01-01

    ERTS-1 imagery is a useful source of data for evaluation of earth resources in Southern California. The improving quality of ERTS-1 imagery, and our increasing ability to enhance the imagery has resulted in studies of a variety of phenomena in several Southern California environments. These investigations have produced several significant results of varying detail. They include the detection and identification of macro-scale tectonic and vegetational patterns, as well as detailed analysis of urban and agricultural processes. The sequential nature of ERTS-1 imagery has allowed these studies to monitor significant changes in the environment. In addiation, some preliminary work has begun directed toward assessing the impact of expanding recreation, agriculture and urbanization into the fragile desert environment. Refinement of enhancement and mapping techniques and more intensive analysis of ERTS-1 imagery should lead to a greater capability to extract detailed information for more precise evaluations and more accurate monitoring of earth resources in Southern California.

  6. The debate on the use of linear no threshold for assessing the effects of low doses.

    PubMed

    Tubiana, M; Aurengo, A; Averbeck, D; Masse, R

    2006-09-01

    From December 2004 to July 2005, three reports on the effects of low doses of ionising radiation were released: ICRP (2004), the joint report of the French Academies of Science and Medicine (Tubiana et al 2005), and a report from the American Academy of Sciences (BEIR VII 2005). These reports quote the same recent articles on the biological effects of low doses, yet their conclusions diverge. The French report concludes that recent biological data show that the efficacy of defense mechanisms is modulated by dose and dose rate and that linear no threshold (LNT) is no longer plausible. The ICRP and the BEIR VII reports recognise that there are biologic arguments against LNT but feel that there are not sufficient biological proofs against it to change risk assessment methodology and subsequent regulatory policy based on LNT. They point out the remaining uncertainties and the lack of mechanistic explanations of phenomena such as low dose hyperlethality or the adaptive response. In this context, a critical analysis of the available data is necessary. The epidemiological data and the experimental data challenge the validity of the LNT hypothesis for assessing the carcinogenic effect of low doses, but do not allow its exclusion. Therefore, the main criteria for selecting the most reliable dose-effect relationship from a scientific point of view should be based on biological data. Their analysis should help one to understand the current controversy.

  7. Evaluation of the neutron spectrum and dose assessment around the venus reactor.

    PubMed

    Coeck, Michèle; Vermeersch, Fernand; Vanhavere, Filip

    2005-01-01

    An assessment of the neutron field near the VENUS reactor is made in order to evaluate the neutron dose to the operators, particularly in an area near the reactor shielding and in the control room. Therefore, a full MCNPX model of the shielding geometry was developed. The source term used in the simulation is derived from a criticality calculation done beforehand. Calculations are compared to routine neutron dose rate measurements and show good agreement. The MCNPX model developed easily allows core adaptations in order to evaluate the effect of future core configuration on the neutron dose to the operators.

  8. Large-scale genotoxicity assessments in the marine environment.

    PubMed

    Hose, J E

    1994-12-01

    There are a number of techniques for detecting genotoxicity in the marine environment, and many are applicable to large-scale field assessments. Certain tests can be used to evaluate responses in target organisms in situ while others utilize surrogate organisms exposed to field samples in short-term laboratory bioassays. Genotoxicity endpoints appear distinct from traditional toxicity endpoints, but some have chemical or ecotoxicologic correlates. One versatile end point, the frequency of anaphase aberrations, has been used in several large marine assessments to evaluate genotoxicity in the New York Bight, in sediment from San Francisco Bay, and following the Exxon Valdez oil spill.

  9. Large-scale genotoxicity assessments in the marine environment.

    PubMed Central

    Hose, J E

    1994-01-01

    There are a number of techniques for detecting genotoxicity in the marine environment, and many are applicable to large-scale field assessments. Certain tests can be used to evaluate responses in target organisms in situ while others utilize surrogate organisms exposed to field samples in short-term laboratory bioassays. Genotoxicity endpoints appear distinct from traditional toxicity endpoints, but some have chemical or ecotoxicologic correlates. One versatile end point, the frequency of anaphase aberrations, has been used in several large marine assessments to evaluate genotoxicity in the New York Bight, in sediment from San Francisco Bay, and following the Exxon Valdez oil spill. PMID:7713029

  10. Large-scale genotoxicity assessments in the marine environment

    SciTech Connect

    Hose, J.E.

    1994-12-01

    There are a number of techniques for detecting genotoxicity in the marine environment, and many are applicable to large-scale field assessments. Certain tests can be used to evaluate responses in target organisms in situ while others utilize surrogate organisms exposed to field samples in short-term laboratory bioassays. Genotoxicity endpoints appear distinct from traditional toxicity endpoints, but some have chemical or ecotoxicologic correlates. One versatile end point, the frequency of anaphase aberrations, has been used in several large marine assessments to evaluate genotoxicity in the New York Bight, in sediment from San Francisco Bay, and following the Exxon Valdez oil spill. 31 refs., 2 tabs.

  11. [Hygienic assessment of the environment of a territorial industrial complex].

    PubMed

    Tsunina, N M

    2002-01-01

    Hygienic assessment of the time course of changes in environmental pollution has determined Novokuibyshevsk, Samara Region, as an ecologically poor area. Its findings are a primary basis for: 1) systemic stepwise study of an environment-health relationship; 2) elucidation of priority and early undetermined risk factors; 3) development of current measures for environmental sanitation and human health promotion in the specifically studied area; 4) definition of new tasks in the field of hygienic studies.

  12. Assessing the Clinical Impact of Approximations in Analytical Dose Calculations for Proton Therapy

    SciTech Connect

    Schuemann, Jan Giantsoudi, Drosoula; Grassberger, Clemens; Moteabbed, Maryam; Min, Chul Hee; Paganetti, Harald

    2015-08-01

    Purpose: To assess the impact of approximations in current analytical dose calculation methods (ADCs) on tumor control probability (TCP) in proton therapy. Methods: Dose distributions planned with ADC were compared with delivered dose distributions as determined by Monte Carlo simulations. A total of 50 patients were investigated in this analysis with 10 patients per site for 5 treatment sites (head and neck, lung, breast, prostate, liver). Differences were evaluated using dosimetric indices based on a dose-volume histogram analysis, a γ-index analysis, and estimations of TCP. Results: We found that ADC overestimated the target doses on average by 1% to 2% for all patients considered. The mean dose, D95, D50, and D02 (the dose value covering 95%, 50% and 2% of the target volume, respectively) were predicted within 5% of the delivered dose. The γ-index passing rate for target volumes was above 96% for a 3%/3 mm criterion. Differences in TCP were up to 2%, 2.5%, 6%, 6.5%, and 11% for liver and breast, prostate, head and neck, and lung patients, respectively. Differences in normal tissue complication probabilities for bladder and anterior rectum of prostate patients were less than 3%. Conclusion: Our results indicate that current dose calculation algorithms lead to underdosage of the target by as much as 5%, resulting in differences in TCP of up to 11%. To ensure full target coverage, advanced dose calculation methods like Monte Carlo simulations may be necessary in proton therapy. Monte Carlo simulations may also be required to avoid biases resulting from systematic discrepancies in calculated dose distributions for clinical trials comparing proton therapy with conventional radiation therapy.

  13. Patient doses in {gamma}-intracoronary radiotherapy: The Radiation Burden Assessment Study

    SciTech Connect

    Thierens, Hubert . E-mail: hubert.thierens@Ughent.be; Reynaert, Nick; Bacher, Klaus; Eijkeren, Marc van; Taeymans, Yves

    2004-10-01

    Purpose: To determine accurately the radiation burden of both patients and staff from intracoronary radiotherapy (IRT) with {sup 192}Ir and to investigate the importance of IRT in the patient dose compared with interventional X-rays. Methods and materials: The Radiation Burden Assessment Study (RABAS) population consisted of 9 patients undergoing {gamma}-IRT after percutaneous transluminal coronary angioplasty and 14 patients undergoing percutaneous transluminal coronary angioplasty only as the control group. For each patient, the dose to the organs and tissues from the internal and external exposure was determined in detail by Monte Carlo N-particle simulations. Patient skin dose measurements with thermoluminescence dosimeters served as verification. Staff dosimetry was performed with electronic dosimeters, thermoluminescence dosimeters, and double film badge dosimetry. Results: With respect to the patient dose from IRT, the critical organs are the thymus (58 mGy), lungs (31 mGy), and esophagus (27 mGy). The mean effective dose from IRT was 8 mSv. The effective dose values from interventional X-rays showed a broad range (2-28 mSv), with mean values of 8 mSv for the IRT patients and 13 mSv for the control group. The mean dose received by the radiotherapist from IRT was 4 {mu}Sv/treatment. The doses to the other staff members were completely negligible. Conclusion: Our results have shown that the patient and personnel doses in {gamma}-IRT remain at an acceptable level. The patient dose from IRT was within the variations in dose from the accompanying interventional X-rays.

  14. Generic performance assessment for a deep repository for low and intermediate level waste in the UK--a case study in assessing radiological impacts on the natural environment.

    PubMed

    Jones, S R; Patton, D; Copplestone, D; Norris, S; O'Sullivan, P

    2003-01-01

    Concentrations of radionuclides in soil and surface water, taken from a generic performance assessment of a repository for low and intermediate level radioactive waste, assumed to be located in the UK, have been used as the basis for a case study in assessing radiological impacts on the natural environment. Simplified descriptions of the terrestrial and aquatic ecosystem types likely to be impacted have been developed. A scoping assessment has identified (226)Ra, (210)Po, (234)U, (230)Th and (238)U as having the highest potential for impact, with doses from internally incorporated alpha emitters as being potentially of particular importance. These nuclides, together with (36)Cl and (129)I (which have proved to be of importance in radiological risk assessments for humans) were included in a more detailed dose assessment. A basic methodology for dose assessment of ecosystems is described, and has been applied for the defined impacted ecosystems. Paucity of published data on concentration factors prevented a more detailed assessment for terrestrial ecosystems. For the aquatic ecosystem, a more detailed assessment was possible and highest calculated absorbed dose rates (weighted for the likely higher biological effectiveness of alpha radiation) were about 6.5 microGy h(-1). We conclude that harm to the impacted ecosystems is unlikely and make the observation that the lack of concentration factor or transfer factor data for a sufficiently wide range of species, ecosystems and nuclides appears to be the principal obstacle to establishing a comprehensive framework for the application of radiological protection to ecosystems.

  15. Assessment of radiation awareness training in immersive virtual environments

    NASA Astrophysics Data System (ADS)

    Whisker, Vaughn E., III

    The prospect of new nuclear power plant orders in the near future and the graying of the current workforce create a need to train new personnel faster and better. Immersive virtual reality (VR) may offer a solution to the training challenge. VR technology presented in a CAVE Automatic Virtual Environment (CAVE) provides a high-fidelity, one-to-one scale environment where areas of the power plant can be recreated and virtual radiation environments can be simulated, making it possible to safely expose workers to virtual radiation in the context of the actual work environment. The use of virtual reality for training is supported by many educational theories; constructivism and discovery learning, in particular. Educational theory describes the importance of matching the training to the task. Plant access training and radiation worker training, common forms of training in the nuclear industry, rely on computer-based training methods in most cases, which effectively transfer declarative knowledge, but are poor at transferring skills. If an activity were to be added, the training would provide personnel with the opportunity to develop skills and apply their knowledge so they could be more effective when working in the radiation environment. An experiment was developed to test immersive virtual reality's suitability for training radiation awareness. Using a mixed methodology of quantitative and qualitative measures, the subjects' performances before and after training were assessed. First, subjects completed a pre-test to measure their knowledge prior to completing any training. Next they completed unsupervised computer-based training, which consisted of a PowerPoint presentation and a PDF document. After completing a brief orientation activity in the virtual environment, one group of participants received supplemental radiation awareness training in a simulated radiation environment presented in the CAVE, while a second group, the control group, moved directly to the

  16. Radiological assessment of worker doses during sludge mobilization and removal at the Melton Valley storage tanks

    SciTech Connect

    Kerr, G.D.; Coleman, R.L.; Kocher, D.C.; Wynn, C.C.

    1996-12-17

    This report presents an assessment of potential radiation doses to workers during mobilization and removal of contaminated sludges from the Melton Valley Storage Tanks at Oak Ridge National Laboratory. The assessment is based on (1) measurements of radionuclide concentrations in sludge and supernatant liquid samples from the waste storage tanks, (2) measurements of gamma radiation levels in various areas that will be accessed by workers during normal activities, (3) calculations of gamma radiation levels for particular exposure situations, especially when the available measurements are not applicable, and (4) assumed scenarios for worker activities in radiation areas. Only doses from external exposure are estimated in this assessment. Doses from internal exposure are assumed to be controlled by containment of radioactive materials or respiratory protection of workers and are not estimated.

  17. An appraisal of critical effect sizes for the benchmark dose approach to assess dose-response relationships in genetic toxicology.

    PubMed

    Zeller, Andreas; Duran-Pacheco, Gonzalo; Guérard, Melanie

    2017-08-10

    The benchmark dose (BMD) concept is increasingly utilized to analyze quantitative dose-response relationships in genetic toxicology. This methodology requires the user (i.e. the toxicologist) to a priori define a small increase over controls that is "acceptable" to be induced by a genotoxic test substance. The increase is called benchmark response (BMR) or critical effect size (CES), depending on the software used. To render the metrics calculated from the data of animals treated with the test substance applicable for risk assessment, the BMR or CES must represent biologically relevant changes of parameters measured in in vivo genotoxicity assays such as the Micronucleus, Comet, Transgenic rodent or Pig-a assay. Current recommendations for CES in genotoxicology are arbitrary (10% increase over mean vehicle controls) or based on limited, usually 5-6, data points (i.e. the standard deviation of the concurrent vehicle control group). We have, therefore, analyzed historical vehicle control data of standard in vivo genotoxicity test systems with statistical methods. Based on this evaluation, we illustrate limitations of the currently recommended CES values and propose a pragmatic approach that may contribute to better defining endpoint-specific CES values for BMD software like PROAST.

  18. Computed tomography dose assessment for a 160 mm wide, 320 detector row, cone beam CT scanner.

    PubMed

    Geleijns, J; Salvadó Artells, M; de Bruin, P W; Matter, R; Muramatsu, Y; McNitt-Gray, M F

    2009-05-21

    Computed tomography (CT) dosimetry should be adapted to the rapid developments in CT technology. Recently a 160 mm wide, 320 detector row, cone beam CT scanner that challenges the existing Computed Tomography Dose Index (CTDI) dosimetry paradigm was introduced. The purpose of this study was to assess dosimetric characteristics of this cone beam scanner, to study the appropriateness of existing CT dose metrics and to suggest a pragmatic approach for CT dosimetry for cone beam scanners. Dose measurements with a small Farmer-type ionization chamber and with 100 mm and 300 mm long pencil ionization chambers were performed free in air to characterize the cone beam. According to the most common dose metric in CT, namely CTDI, measurements were also performed in 150 mm and 350 mm long CT head and CT body dose phantoms with 100 mm and 300 mm long pencil ionization chambers, respectively. To explore effects that cannot be measured with ionization chambers, Monte Carlo (MC) simulations of the dose distribution in 150 mm, 350 mm and 700 mm long CT head and CT body phantoms were performed. To overcome inconsistencies in the definition of CTDI100 for the 160 mm wide cone beam CT scanner, doses were also expressed as the average absorbed dose within the pencil chamber (D100). Measurements free in air revealed excellent correspondence between CTDI300air and D100air, while CTDI100air substantially underestimates CTDI300air. Results of measurements in CT dose phantoms and corresponding MC simulations at centre and peripheral positions were weighted and revealed good agreement between CTDI300w, D100w and CTDI600w, while CTDI100w substantially underestimates CTDI300w. D100w provides a pragmatic metric for characterizing the dose of the 160 mm wide cone beam CT scanner. This quantity can be measured with the widely available 100 mm pencil ionization chamber within 150 mm long CT dose phantoms. CTDI300w measured in 350 mm long CT dose phantoms serves as an appropriate standard of

  19. Evaluating quantitative formulas for dose-response assessment of chemical mixtures.

    PubMed

    Hertzberg, Richard C; Teuschler, Linda K

    2002-12-01

    Risk assessment formulas are often distinguished from dose-response models by being rough but necessary. The evaluation of these rough formulas is described here, using the example of mixture risk assessment. Two conditions make the dose-response part of mixture risk assessment difficult, lack of data on mixture dose-response relationships, and the need to address risk from combinations of chemicals because of public demands and statutory requirements. Consequently, the U.S. Environmental Protection Agency has developed methods for carrying out quantitative dose-response assessment for chemical mixtures that require information only on the toxicity of single chemicals and of chemical pair interactions. These formulas are based on plausible ideas and default parameters but minimal supporting data on whole mixtures. Because of this lack of mixture data, the usual evaluation of accuracy (predicted vs. observed) cannot be performed. Two approaches to the evaluation of such formulas are to consider fundamental biological concepts that support the quantitative formulas (e.g., toxicologic similarity) and to determine how well the proposed method performs under simplifying constraints (e.g., as the toxicologic interactions disappear). These ideas are illustrated using dose addition and two weight-of-evidence formulas for incorporating toxicologic interactions.

  20. Occupational radiation dose assessment for the DOE spent-fuel storage facility

    SciTech Connect

    Hadley, J.; Eble, R.G. Jr.

    1997-12-01

    To expedite the licensing process of the centralized interim storage facility (CISF), the U.S. Department of Energy has completed a CISF topical safety analysis report (TSAR). The TSAR will be used in licensing the CISF when a site is designated. An occupational radiation dose assessment of the facility operations is performed as part of the CISF design. The first phase of the CISF has the capability to receive, transfer, and store spent nuclear fuel (SNF) in dual-purpose casks. Currently, there are five vendor technologies under consideration. The preliminary dose assessment is based on estimated occupational exposures using traditional power plant independent spent-fuel storage installation (ISFSI) and transport cask-handling processes. The second step in the process is to recommend as-low-as-reasonably-achievable (ALARA) techniques to reduce potential exposures. A final dose assessment is completed implementing the ALARA techniques, and a review is performed to ensure that the design is in compliance with regulatory criteria. The dose assessment and ALARA evaluation are determined using the following input information: dose estimates from vendor safety analysis reports, ISFSI experience with similar systems, traditional methods of operations, expected CISF cask receipt rates, and feasible ALARA techniques.

  1. Assessment of Organ Doses for a Glovebox Worker Using Realistic Postures with PIMAL and VOXMAT

    SciTech Connect

    Akkurt, Hatice; Bekar, Kursat; Eckerman, Keith F

    2009-01-01

    In an earlier effort, the Oak Ridge National Laboratory (ORNL) mathematical phantom has been revised to enable assessment of radiation dose for different postures in occupational exposures by enabling freely positioning arms and legs. The revised phantom is called PIMAL: Phantom wIth Moving Arms and Legs. Further, to assist the analyst with input preparation and output manipulation for different postures, a graphical user interface has been developed. Also, at ORNL a hybrid computational phantom, which uses a combination of voxelized and stylized geometry, for radiation dose assessment was recently developed. This phantom is based on the International Commission on Radiological Protection's (ICRP's) male phantom model and is called VOXMAT. For VOXMAT, the head and torso, which contain significant anatomical details, were described using voxel geometry. The arms and legs, which contain less-detailed anatomical structures, were modeled using the mathematical equations (stylized approach). With this approach the number of voxels was reduced from 7 million to 2.3 million, which translated into a proportional reduction in computational time and memory requirements. More importantly, VOXMAT allows easy the movement of arms and legs for radiation dose assessment for realistic postures. To determine/demonstrate the importance of the realistic posture for a case study, PIMAL and VOXMAT are applied to assess the dose to a glovebox worker. In this paper, the comparative computational results for the estimated dose are presented.

  2. An updated dose assessment for a U.S. Nuclear Test Site - Bikini Atoll

    SciTech Connect

    Robison, W.L.; Bogen, K.T.; Conrado, C.L.

    1995-10-01

    On March 1, 1954, a nuclear weapon test, code-named BRAVO, conducted at Bikini Atoll in the northern Marshall Islands contaminated the major residence island. There has been a continuing effort since 1977 to refine dose assessments for resettlement options at Bikini Atoll. Here we provide a radiological dose assessment for the main residence island, Bikini, using extensive radionuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island as part of our continuing research and monitoring program that began in 1975. The unique composition of coral soil greatly alters the relative contribution of cesium-137 ({sup 137}Cs) and strontium-90 ({sup 90}Sr) to the total estimated dose relative to expectations based on North American and European soils. Without counter measures, cesium-137 produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The doses are calculated assuming a resettlement date of 1999. The estimated maximum annual effective dose for current island conditions is 4.0 mSv when imported foods, which are now an established part of the diet, are available. The corresponding 30-, 50-, and 70-y integral effective doses are 9.1 cSv, 13 cSv, and 15 cSv, respectively. A corresponding uncertainty analysis showed that after about 5 y of residence, the 95% confidence limits on population-average dose would be {plus_minus}35% of its expected value. We have evaluated various countermeasures to reduce {sup 137}Cs in food crops. Treatment with potassium reduces the uptake of {sup 137}Cs into food crops, and therefore the ingestion dose, to about 5% of pretreatment levels and has essentially no negative environmental consequences.

  3. Environmental assessments in the built environment: crucial yet underdeveloped

    NASA Astrophysics Data System (ADS)

    Heinonen, Jukka; Horvath, Arpad; Junnila, Seppo

    2015-03-01

    Environmental assessments have been developed with increasing emphasis since the wide-scale emergence of environmental concerns in the 1970s. However, after decades there is still plenty of room left for development. These assessments are also rapidly becoming more and more crucial as we seem to be reaching the boundaries of the carrying capacity of our planet. Assessments of the emissions from the built environment and especially of the interactions between human communities and emissions are in a very central role in the quest to solve the great problem of sustainable living. Policy- makers and professionals in various fields urgently need reliable data on the current conditions and realistic future projections, as well as robust and scientifically defensible models for decision making. This recognition was the main motivation to call for this Focus Issue, and the published contributions truly highlight the same point. This editorial provides brief summaries and discussions on the 16 articles of the Focus Issue, depicting the several interesting perspectives they offer to advance the state of the art. Now we encourage academics, practitioners, government, industry, individual consumers, and other decision makers to utilize the available findings and develop the domain of environmental assessment of the built environment further. Indeed, we hope that this Focus Issue is merely a kernel of a significantly large future body of literature.

  4. Pedigree management and assessment in a net-centric environment

    NASA Astrophysics Data System (ADS)

    Gioioso, Marisa M.; McCullough, S. Daryl; Cormier, Jennifer P.; Marceau, Carla; Joyce, Robert A.

    2007-04-01

    Modern Defense strategy and execution is increasingly net-centric, making more information available more quickly. In this environment, the intelligence agent or warfighter must distinguish decision-quality information from potentially inaccurate, or even conflicting, pieces of information from multiple sources - often in time-critical situations. The Pedigree Management and Assessment Framework (PMAF) enables the publisher of information to record standard provenance metadata about the source, manner of collection, and the chain of modification of information as it passed through processing and/or assessment. In addition, the publisher can define and include other metadata relevant to quality assessment, such as domain-specific metadata about sensor accuracy or the organizational structure of agencies. PMAF stores this potentially enormous amount of metadata compactly and presents it to the user in an intuitive graphical format, together with PMAF-generated assessments that enable the user to quickly estimate information quality. PMAF has been created for a net-centric information management system; it can access pedigree information across communities of interest (COIs) and across network boundaries and will also be implemented in a Web Services environment.

  5. Systematic review and meta-analysis of the risk of microbial contamination of parenteral doses prepared under aseptic techniques in clinical and pharmaceutical environments: an update.

    PubMed

    Austin, P D; Hand, K S; Elia, M

    2015-12-01

    Administration of parenteral doses with microbial contamination can lead to infective morbidity or death. To test whether aseptic preparation of parenteral doses or additives to sterile doses undertaken in dedicated pharmaceutical rather than clinical environments reduces the risk of microbial dose contamination. Data identified from a systematic review were examined using random effects meta-analyses, and t-tests were used to compare dose contamination frequencies. In all, 16,552 doses from 34 studies (33 records) were identified. For all the data combined there was a significantly higher frequency of contamination of doses prepared in clinical than in pharmaceutical environments {3.7% [95% confidence interval (CI): 2.2, 6.2; N = 10,272 doses] vs 0.5% (95% CI: 0.1, 1.6; N = 6280 doses); P = 0.007}. Contamination of doses was significantly higher when prepared as individual lots than as part of a batch in pharmaceutical environments [2.1% (95% CI: 0.7, 5.8; N = 168 doses) vs 0.2% (95% CI: 0.1, 0.9; N = 6112 doses); P = 0.002]. There was a significantly higher frequency of dose contamination if additions were made to sterile parenteral doses in clinical environments [risk ratio: 2.121 (95% CI: 1.093, 4.114); P = 0.026]. The overall quality of the studies was judged to be low. Reported rates of parenteral dose contamination were orders of magnitude higher than accepted reference standards, which may increase infection risk. The limited evidence on contamination rates supports dose preparation in pharmaceutical rather than clinical environments, and does not support batch preparation in clinical environments. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  6. Assessment of plutonium in the Savannah River Site environment. Revision 1

    SciTech Connect

    Carlton, W.H.; Evans, A.G.; Geary, L.A.; Murphy, C.E. Jr.; Pinder, J.E.; Strom, R.N.

    1992-12-31

    Plutonium in the Savannah River Site Environment is published as a part of the Radiological Assessment Program (RAP). It is the fifth in a series of eight documents on individual radioisotopes released to the environment as a result of Savannah River Site (SRS) operations. These are living documents, each to be revised and updated on a two-year schedule. This document describes the sources of plutonium in the environment, its release from SRS, environmental transport and ecological concentration of plutonium, and the radiological impact of SRS releases to the environment. Plutonium exists in the environment as a result of above-ground nuclear weapons tests, the Chernobyl accident, the destruction of satellite SNAP 9-A, plane crashes involving nuclear weapons, and small releases from reactors and reprocessing plants. Plutonium has been produced at SRS during the operation of five production reactors and released in small quantities during the processing of fuel and targets in chemical separations facilities. Approximately 0.6 Ci of plutonium was released into streams and about 12 Ci was released to seepage basins, where it was tightly bound by clay in the soil. A smaller quantity, about 3.8 Ci, was released to the atmosphere. Virtually all releases have occurred in F- and H-Area separation facilities. Plutonium concentration and transport mechanisms for the atmosphere, surface water, and ground water releases have been extensively studied by Savannah River Technology Center (SRTC) and ecological mechanisms have been studied by Savannah River Ecology Laboratory (SREL). The overall radiological impact of SRS releases to the offsite maximum individual can be characterized by a total dose of 15 mrem (atmospheric) and 0.18 mrem (liquid), compared with the dose of 12,960 mrem from non-SRS sources during the same period of time (1954--1989). Plutonium releases from SRS facilities have resulted in a negligible impact to the environment and the population it supports.

  7. Performance Assessment of Prediction In Dynamic Environments (PRIDE) in Manufacturing Environments

    SciTech Connect

    Kootbally, Zeid; Schlenoff, Craig; Madhavan, Raj

    2009-01-01

    This paper describes PRIDE (Prediction in Dynamic Environments), a multi-resolution and hierarchical framework. PRIDE was developed as a test bed to assess the performance of autonomous vehicles in the presence of moving objects in a simulated environment. By simulating scenarios in which moving objects are prevalent, a designer of an autonomous vehicle can test the performance of their path planning and collision avoidance algorithms without having to immerse the vehicle in the physical world. This framework supports the prediction of the future location of moving objects at various levels of resolution, thus providing prediction information at the frequency and level of abstraction necessary for planners at different levels within the hierarchy. Previous works have demonstrated the reliability of PRIDE to simulate on-road traffic situations with multiple vehicles. To provide realistic scenarios, PRIDE integrates a level of situation awareness of how other vehicles in the environment are expected to behave considering the situation in which the vehicles find themselves in. In recent efforts, the PRIDE framework has been extended to consider production logistics in dynamic manufacturing environment while focusing on the scheduling of material transportation system. To demonstrate the characteristics of the PRIDE framework, this paper illustrates real-time navigation of Automated Guided Vehicles (AGVs) at different locations in a dynamic manufacturing environment. Moreover, using the high-fidelity physics?based framework for the Unified System for Automation and Robot Simulation (USARSim), this paper analyzes the performance of the PRIDE framework on a set of realistic scenarios.

  8. Effect of Low-Dose MDCT and Iterative Reconstruction on Trabecular Bone Microstructure Assessment

    PubMed Central

    Baum, Thomas; Nasirudin, Radin A.; Mei, Kai; Garcia, Eduardo G.; Burgkart, Rainer; Rummeny, Ernst J.; Kirschke, Jan S.; Noël, Peter B.

    2016-01-01

    We investigated the effects of low-dose multi detector computed tomography (MDCT) in combination with statistical iterative reconstruction algorithms on trabecular bone microstructure parameters. Twelve donated vertebrae were scanned with the routine radiation exposure used in our department (standard-dose) and a low-dose protocol. Reconstructions were performed with filtered backprojection (FBP) and maximum-likelihood based statistical iterative reconstruction (SIR). Trabecular bone microstructure parameters were assessed and statistically compared for each reconstruction. Moreover, fracture loads of the vertebrae were biomechanically determined and correlated to the assessed microstructure parameters. Trabecular bone microstructure parameters based on low-dose MDCT and SIR significantly correlated with vertebral bone strength. There was no significant difference between microstructure parameters calculated on low-dose SIR and standard-dose FBP images. However, the results revealed a strong dependency on the regularization strength applied during SIR. It was observed that stronger regularization might corrupt the microstructure analysis, because the trabecular structure is a very small detail that might get lost during the regularization process. As a consequence, the introduction of SIR for trabecular bone microstructure analysis requires a specific optimization of the regularization parameters. Moreover, in comparison to other approaches, superior noise-resolution trade-offs can be found with the proposed methods. PMID:27447827

  9. Impact assessment of land use planning driving forces on environment

    SciTech Connect

    Chen, Longgao; Yang, Xiaoyan; Chen, Longqian; Li, Long

    2015-11-15

    Land use change may exert a negative impact on environmental quality. A state–impact–state (SIS) model describing a state transform under certain impacts has been integrated into land use planning (LUP) environmental impact assessment (LUPEA). This logical model is intuitive and easy to understand, but the exploration of impact is essential to establish the indicator system and to identify the scope of land use environmental impact when it is applied to a specific region. In this study, we investigated environmental driving forces from land use planning (LUPF), along with the conception, components, scope, and impact of LUPF. This method was illustrated by a case study in Zoucheng, China. Through the results, we concluded that (1) the LUPF on environment are impacts originated from the implementation of LUP on a regional environment, which are characterized by four aspects: magnitude, direction, action point, and its owner; (2) various scopes of LUPF on individual environmental elements based on different standards jointly define the final scope of LUPEA; (3) our case study in Zoucheng demonstrates the practicability of this proposed approach; (4) this method can be embedded into LUPEA with direction, magnitudes, and scopes of the LUPF on individual elements obtained, and the identified indicator system can be directly employed into LUPEA and (5) the assessment helps to identify key indicators and to set up a corresponding strategy to mitigate the negative impact of LUP on the environment, which are two important objectives of strategic environmental assessment (SEA) in LUP. - Highlights: • Environmental driving forces from land use planning (LUPF) are investigated and categorized. • Our method can obtains the direction, magnitudes and scopes of environmental driving forces. • The LUPEA scope is determined by the combination of various scopes of LUPF on individual elements. • LUPF assessment can be embedded into LUPEA. • The method can help to

  10. Effect of low-dose CT and iterative reconstruction on trabecular bone microstructure assessment

    NASA Astrophysics Data System (ADS)

    Kopp, Felix K.; Baum, Thomas; Nasirudin, Radin A.; Mei, Kai; Garcia, Eduardo G.; Burgkart, Rainer; Rummeny, Ernst J.; Bauer, Jan S.; Noël, Peter B.

    2016-03-01

    The trabecular bone microstructure is an important factor in the development of osteoporosis. It is well known that its deterioration is one effect when osteoporosis occurs. Previous research showed that the analysis of trabecular bone microstructure enables more precise diagnoses of osteoporosis compared to a sole measurement of the mineral density. Microstructure parameters are assessed on volumetric images of the bone acquired either with high-resolution magnetic resonance imaging, high-resolution peripheral quantitative computed tomography or high-resolution computed tomography (CT), with only CT being applicable to the spine, which is one of clinically most relevant fracture sites. However, due to the high radiation exposure for imaging the whole spine these measurements are not applicable in current clinical routine. In this work, twelve vertebrae from three different donors were scanned with standard and low radiation dose. Trabecular bone microstructure parameters were assessed for CT images reconstructed with statistical iterative reconstruction (SIR) and analytical filtered backprojection (FBP). The resulting structure parameters were correlated to the biomechanically determined fracture load of each vertebra. Microstructure parameters assessed for low-dose data reconstructed with SIR significantly correlated with fracture loads as well as parameters assessed for standard-dose data reconstructed with FBP. Ideal results were achieved with low to zero regularization strength yielding microstructure parameters not significantly different from those assessed for standard-dose FPB data. Moreover, in comparison to other approaches, superior noise-resolution trade-offs can be found with the proposed methods.

  11. Assessing the dose-dependency of allometric scaling performance using physiologically based pharmacokinetic modeling.

    PubMed

    Kirman, C R; Sweeney, L M; Meek, M E; Gargas, M L

    2003-12-01

    The performance of allometric scaling of dose as a power of body weight under a variety of extrapolation conditions with respect to species, route, exposure intensity, and mechanism/mode of action, remains untested in many cases. In this paper, animal-human internal dose ratio comparisons have been developed for 12 chemicals (benzene, carbon tetrachloride, chloroform, diisopropylfluorophosphate, ethanol, ethylene oxide, methylene chloride, methylmercury, styrene, tetrachloroethene, trichloroethene, and vinyl chloride). This group of predominantly volatile and lipophilic chemicals was selected on the basis that their kinetics have been well-studied and can be predicted in mice, rats, and humans using physiologically based pharmacokinetic (PBPK) models. PBPK model predictions were compared to the allometric scaling predictions for interspecies extrapolation. Recommendations for the application of the allometric scaling are made with reference to internal dose measure (mode of action) and concentration level. The results of this assessment generally support the use of scaling factors recommended in the published literature, which includes scaling factors of 1.0 for risk assessments in which toxicity is attributed to the parent chemical or stable metabolite, and -0.75 for dose-response assessments in which toxicity is attributed to the formation of a reactive metabolite from an inhaled compound. A scaling factor of 0.75 is recommended for dose-response assessments of orally administered compounds in which toxicity is attributed to the parent chemical or stable metabolite and 1.0 for risk assessments in which toxicity is attributed to the formation of a reactive metabolite from a compound administered by the oral route. A dose-dependency in the results suggests that the scaling factors appropriate at high exposures may differ from those at low exposures, primarily due to the impact of saturable metabolism.

  12. Dose assessment following an overexposure of a worker at a Swiss nuclear power plant.

    PubMed

    Bailat, Claude J; Laedermann, Jean-Pascal; Baechler, Sébastien; Desorgher, Laurent; Aroua, Abbas; Bochud, François O

    2017-07-27

    The aim of this work was to assess the doses received by a diver exposed to a radiation source during maintenance work in the fuel transfer pool at a Swiss nuclear power plant, and to define whether the statutory limit was breached or not. Onsite measurements were carried out and different scenarios were simulated using the MicroShield Software and the MCNPX Monte Carlo radiation transport code to estimate the activity of the irradiating object as well as the doses to the limbs and the effective dose delivered to the operator. The activity of the object was estimated to 1.8 TBq. From the various dose estimations, a conservative value of 7.5 Sv was proposed for the equivalent dose to the skin on the hands and an effective dose of 28 mSv. The use of different experimental and calculation methods allowed us to accurately estimate the activity of the object and the dose delivered to the diver, useful information for making a decision on the most appropriate scheme of follow up for the patient.

  13. A A field test for extremity dose assessment during outages at Korean nuclear power plants.

    PubMed

    Kim, Hee Geun; Kong, Tae Young

    2013-05-01

    During maintenance on the water chamber of a steam generator, the pressuriser heater and the pressure tube feeder in nuclear power plants, workers are likely to receive high radiation doses due to the severe workplace conditions. In particular, it is expected that workers' hands would receive the highest radiation doses because of their contact with the radioactive materials. In this study, field tests for extremity dose assessments in radiation workers undertaking contact tasks with high radiation doses were conducted during outages at pressurised water reactors and pressurised heavy water reactors in Korea. In the test, the radiation workers were required to wear additional thermoluminescent dosemeters (TLDs) on their backs and wrists and an extremity dosemeter on the finger, as well as a main TLD on the chest while performing the maintenance tasks.

  14. EVALUATION OF PROMPT DOSE ENVIRONMENT IN THE NATIONAL IGNITION FACILITY DURING D-D AND THD SHOTS

    SciTech Connect

    Khater, H; Dauffy, L; Sitaraman, S; Brereton, S

    2009-04-28

    Evaluation of the prompt dose environment expected in the National Ignition Facility (NIF) during Deuterium-Deuterium (D-D) and Tritium-Hydrogen-Deuterium (THD) shots have been completed. D-D shots resulting in the production of an annual fusion yield of up to 2.4 kJ (200 shots with 10{sup 13} neutrons per shot) are considered. During the THD shot campaign, shots generating a total of 2 x 10{sup 14} neutrons per shot are also planned. Monte Carlo simulations have been performed to estimate prompt dose values inside the facility as well as at different locations outside the facility shield walls. The Target Chamber shielding, along with Target Bay and Switchyard walls, roofs, and shield doors (when needed) will reduce dose levels in occupied areas to acceptable values during these shot campaigns. The calculated dose values inside occupied areas are small, estimated at 25 and 85 {micro}rem per shot during the D-D and THD shots, respectively. Dose values outside the facility are insignificant. The nearest building to the NIF facility where co-located workers may reside is at a distance of about 100 m from the Target Chamber Center (TCC). The dose in such a building is estimated at a fraction of a ?rem during a D-D or a THD shot. Dose at the nearest site boundary location (350 m from TCC), is caused by skyshine and to a lesser extent by direct radiation. The maximum off-site dose during any of the shots considered is less than 10 nano rem.

  15. Comprehensive assessment of radiation dose estimates for the CORE320 study.

    PubMed

    Rybicki, Frank J; Mather, Richard T; Kumamaru, Kanako K; Brinker, Jeffrey; Chen, Marcus Y; Cox, Christopher; Matheson, Matthew B; Dewey, Marc; DiCarli, Marcelo F; Miller, Julie M; Geleijns, Jacob; George, Richard T; Paul, Narinder; Texter, John; Vavere, Andrea; Yaw, Tan Swee; Lima, Joao A C; Clouse, Melvin E

    2015-01-01

    OBJECTIVE. The purpose of this study was to comprehensively study estimated radiation doses for subjects included in the main analysis of the Combined Non-invasive Coronary Angiography and Myocardial Perfusion Imaging Using 320 Detector Computed Tomography (CORE320) study ( ClinicalTrials.gov identifier NCT00934037), a clinical trial comparing combined CT angiography (CTA) and perfusion CT with the reference standard catheter angiography plus myocardial perfusion SPECT. SUBJECTS AND METHODS. Prospectively acquired data on 381 CORE320 subjects were analyzed in four groups of testing related to radiation exposure. Radiation dose estimates were compared between modalities for combined CTA and perfusion CT with respect to covariates known to influence radiation exposure and for the main clinical outcomes defined by the trial. The final analysis assessed variations in radiation dose with respect to several factors inherent to the trial. RESULTS. The mean radiation dose estimate for the combined CTA and perfusion CT protocol (8.63 mSv) was significantly (p < 0.0001 for both) less than the average dose delivered from SPECT (10.48 mSv) and the average dose from diagnostic catheter angiography (11.63 mSv). There was no significant difference in estimated CTA-perfusion CT radiation dose for subjects who had false-positive or false-negative results in the CORE320 main analyses in a comparison with subjects for whom the CTA-perfusion CT findings were in accordance with the reference standard SPECT plus catheter angiographic findings. CONCLUSION. Radiation dose estimates from CORE320 support clinical implementation of a combined CT protocol for assessing coronary anatomy and myocardial perfusion.

  16. Environment, Safety, and Health Risk Assessment Program (ESHRAP)

    SciTech Connect

    Eide, Steven Arvid; Thomas Wierman

    2003-12-01

    The Environment, Safety and Health Risk Assessment Program (ESHRAP) models human safety and health risk resulting from waste management and environmental restoration activities. Human safety and health risks include those associated with storing, handling, processing, transporting, and disposing of radionuclides and chemicals. Exposures to these materials, resulting from both accidents and normal, incident-free operation, are modeled. In addition, standard industrial risks (falls, explosions, transportation accidents, etc.) are evaluated. Finally, human safety and health impacts from cleanup of accidental releases of radionuclides and chemicals to the environment are estimated. Unlike environmental impact statements and safety analysis reports, ESHRAP risk predictions are meant to be best estimate, rather than bounding or conservatively high. Typically, ESHRAP studies involve risk predictions covering the entire waste management or environmental restoration program, including such activities as initial storage, handling, processing, interim storage, transportation, and final disposal. ESHRAP can be used to support complex environmental decision-making processes and to track risk reduction as activities progress.

  17. Assessing risks of hydrocarbon spills in tropical environments

    NASA Astrophysics Data System (ADS)

    Makarynskyy, Oleg; Makarynska, Dina; Negri, Andrew

    2017-04-01

    There is a growing pressure of exposure to petroleum hydrocarbons in tropical northern Australia. This is due to increasing population and industrial activities, such as oil and gas extraction, ship traffic, and related planned (e.g. wastewater) and accidental (e.g. spills) discharges. Through close collaboration between AIMS and AECOM, a novel, integrated approach to spill risk assessments has been developed. The approach links outcomes of a semi-quantitative risk assessment methodology to results of spill weathering and trajectory numerical modelling and to emerging tropical toxicological data. The risk assessment is based on triple bottom line concept and uses a multi-disciplinary expert panel to assess the probabilities and consequential impacts associated with potential risk events, such as accidental hydrocarbon spills. The probability assessments of spills are based on the type of operations being assessed and historical spill data available for the area and region. Quantifying the impacts of hydrocarbon spills requires an understanding of the impact extents as well as of the sensitivity of relevant tropical species to both hydrocarbons and dispersants. The quantification of impacts for certain operations and areas may only rely on the known nature of hydrocarbons, while spill volumes and extents of slick propagation are highly variable. Critical ecotoxicity data for tropical environments are scarce. Consequentially, assessments of probabilities and impacts may differ dramatically depending on the ambient conditions taken into consideration, level of understanding of properties of spilled hydrocarbon, and numerical models and techniques employed for simulating oil weathering and slick trajectories and thicknesses, as well as the available ecotoxicology thresholds of affected species. The outcomes of the combined risk and impact assessments for the first time provide industry and regulators with advanced pre-spill information thus vastly improving the

  18. A structured approach for the assessment of internal dose: the IDEAS guidelines.

    PubMed

    Doerfel, H; Andrasi, A; Bailey, M; Berkovski, V; Blanchardon, E; Castellani, C-M; Cruz-Suarez, R; Hurtgen, C; LeGuen, B; Malatova, I; Marsh, J; Stather, J; Zeger, J

    2007-01-01

    The need for harmonisation of the procedures for internal dose assessment has been recognised within an EU research project under the 5th Framework Programme. The aim of the IDEAS project was to develop general guidelines for standardising assessments of intakes and internal doses. It started in October 2001 and ended in June 2005. The project is closely related to some goals of the work of Committee 2 of the International Commission on Radiological Protection and since 2003 there has been close co-operation between the two groups. The general philosophy of the guidelines is focusing on the principles of harmonisation, accuracy and proportionality. The proposed system of 'level of task' to structure the approach of internal dose evaluation is also reported. Some details of the internal structure of the guidelines for the different pathways of intake are provided.

  19. Revisions to US EPA Superfund Risk and Dose Assessment Models and Guidance - 13403

    SciTech Connect

    Walker, Stuart A.

    2013-07-01

    The U.S. Environmental Protection Agency (EPA) Superfund program's six Preliminary Remediation Goal (PRG) and Dose Compliance Concentration (DCC) internet based calculators for risk and dose assessment at Superfund sites are being revised to reflect better science, revisions to existing exposure scenarios and new scenarios, and changes to match up more closely with the EPA chemical regional screening level calculator. A revised version of the 1999 guidance document that provides an overview for the Superfund risk assessment process at radioactively contaminated sites, 'Radiation Risk Assessment At CERCLA Sites: Q and A', is being completed that will reflect Superfund recommended guidance and other technical documents issued over the past 13 years. EPA is also issuing a series of fact sheets in the document 'Superfund Radiation Risk Assessment: A Community Tool-kit'. This presentation would go over those changes that are expected to be finished by this spring. (authors)

  20. A dose assessment for a U.S. nuclear test site -- Bikini Atoll

    SciTech Connect

    Robison, W.L.; Bogen, K.T.; Conrado, C.L.

    1993-07-01

    On March 1, 1954, a nuclear weapon test, code-named BRAVO, conducted at Bikini Atoll in the northern Marshall Islands contaminated the major residence island. Here the authors provide a radiological dose assessment for the main residence island, Bikini, using extensive radionuclide concentration data derived from analysis of food crops, ground water, cistern water, fish and other marine species, animals, air, and soil collected at Bikini Island. The unique composition of coral soil greatly alters the relative contribution of cesium-137 and strontium-90 to the total estimated dose relative to expectations based on North American and European soils. Cesium-137 produces 96% of the estimated dose for returning residents, mostly through uptake from the soil to terrestrial food crops but also from external gamma exposure. The estimated maximum annual effective dose is 4.4 mSv y{sup {minus}1} when imported foods, which are now an established part of the diet, are available. The 30-, 50-, and 70-y integral effective doses are 10 cSv, 14 cSv, and 16 cSv, respectively. An analysis of interindividual variability in 0- to 30-y expected integral dose indicates that 95% of Bikini residents would have expected doses within a factor of 3.4 above and 4.8 below the population-average value. A corresponding uncertainty analysis showed that after about 5 y of residence, the 95% confidence limits on population-average dose would be {+-}35% of its expected value. The authors have evaluated various countermeasures to reduce {sup 137}Cs in food crops. Treatment with potassium reduces the uptake of {sup 137}Cs into food crops, and therefore the ingestion dose, to less than 10% of pretreatment levels and has essentially no negative environmental consequences.

  1. Assessment of bilateral filter on 1/2-dose chest-pelvis CT views.

    PubMed

    Al-Hinnawi, Abdel Razzak; Daear, Mohammed; Huwaijah, Said

    2013-07-01

    A bilateral filter (BF) is a non-linear filter that has been proved to de-noise images without overrunning edges. Multi-slice computerized tomography (CT) may employ a BF to participate in dose reduction. This paper quantifies the role of the BF in achieving this objective on 1/2-dose CT. Two sets of CT images are acquired for the chest-pelvis at two different radiation doses. The BF was applied on the 1/2-dose CT images by use of various window sizes. Each time, a set of values of the BF range was fixed while the BF domain was modified. The goal was to observe the behavior of the BF on 1/2-dose CT images in comparison with full-dose CT images. The comparison was carried out by use of four co-occurrence matrix descriptors. Additionally, the peak signal-to-noise ratio (PSNR) and the mean square error (MSE) were reported. The study was applied to the sagittal, coronal, and axial CT views. The results showed that the impact of applying a BF varies among different CT views. The BF can retrieve only part of the signal being lost due to reduction of the radiation dose by one half. Yet, the BF improves the appearance of the 1/2-dose chest-pelvis CT examination. Thus, the BF can contribute to a 50% dose reduction. A procedure for employing the BF on CT machines is proposed. The results also showed that texture descriptors are similar to the PSNR and MSE in providing quantities for assessing medical image quality.

  2. An assessment of the doses received by members of the public in Japan following the nuclear accident at Fukushima Daiichi nuclear power plant.

    PubMed

    Bedwell, P; Mortimer, K; Wellings, J; Sherwood, J; Leadbetter, S J; Haywood, S M; Charnock, T; Jones, A R; Hort, M C

    2015-12-01

    The earthquake and tsunami on 11 March 2011, centred off the east coast of Japan, caused considerable destruction and substantial loss of life along large swathes of the Japanese coastline. The tsunami damaged the Fukushima Daiichi nuclear power plant (NPP), resulting in prolonged releases of radioactive material into the environment. This paper assesses the doses received by members of the public in Japan. The assessment is based on an estimated source term and atmospheric dispersion modelling rather than monitoring data. It is evident from this assessment that across the majority of Japan the estimates of dose are very low, for example they are estimated to be less than the annual average dose from natural background radiation in Japan. Even in the regions local to Fukushima Daiichi NPP (and not affected by any form of evacuation) the maximum lifetime effective dose is estimated to be well below the cumulative natural background dose over the same period. The impact of the urgent countermeasures on the estimates of dose was considered. And the relative contribution to dose from the range of exposure pathways and radionuclides were evaluated. Analysis of estimated doses focused on the geographic irregularity and the impact of the meteorological conditions. For example the dose to an infant's thyroid received over the first year was estimated to be greater in Hirono than in the non-evacuated region of Naraha, despite Hirono being further from the release location. A number of factors were identified and thought to contribute towards this outcome, including the local wind pattern which resulted in the recirculation of part of the release. The non-uniform nature of dose estimates strengthens the case for evaluations based on dispersion modelling.

  3. Radiological-dose assessments of atolls in the northern Marshall Islands

    SciTech Connect

    Robison, W.L.

    1983-04-01

    The Marshall Islands in the Equatorial Pacific, specifically Enewetak and Bikini Atolls, were the site of US nuclear testing from 1946 through 1958. In 1978, the Northern Marshall Islands Radiological Survey was conducted to evaluate the radiological conditions of two islands and ten atolls downwind of the proving grounds. The survey included aerial external gamma measurements and collection of soil, terrestrial, and marine samples for radionuclide analysis to determine the radiological dose from all exposure pathways. The methods and models used to estimate doses to a population in an environment where natural processes have acted on the source-term radionuclides for nearly 30 y, data bases developed for the models, and results of the radiological dose analyses are described.

  4. Assessing Built Environment Walkability using Activity-Space Summary Measures

    PubMed Central

    Tribby, Calvin P.; Miller, Harvey J.; Brown, Barbara B.; Werner, Carol M.; Smith, Ken R.

    2015-01-01

    There is increasing emphasis on active transportation, such as walking, in transportation planning as a sustainable form of mobility and in public health as a means of achieving recommended physical activity and better health outcomes. A research focus is the influence of the built environment on walking, with the ultimate goal of identifying environmental modifications that invite more walking. However, assessments of the built environment for walkability are typically at a spatially disaggregate level (such as street blocks) or at a spatially aggregate level (such as census block groups). A key issue is determining the spatial units for walkability measures so that they reflect potential walking behavior. This paper develops methods for assessing walkability within individual activity spaces: the geographic region accessible to an individual during a given walking trip. We first estimate street network-based activity spaces using the shortest path between known trip starting/ending points and a travel time budget that reflects potential alternative paths. Based on objective walkability measures of the street blocks, we use three summary measures for walkability within activity spaces: i) the average walkability score across block segments (representing the general level of walkability in the activity space); ii) the standard deviation (representing the walkability variation), and; iii) the network autocorrelation (representing the spatial coherence of the walkability pattern). We assess the method using data from an empirical study of built environment walkability and walking behavior in Salt Lake City, Utah, USA. We visualize and map these activity space summary measures to compare walkability among individuals’ trips within their neighborhoods. We also compare summary measures for activity spaces versus census block groups, with the result that they agree less than half of the time. PMID:27213027

  5. Toward a Molecular Equivalent Dose: Use of the Medaka Model in Comparative Risk Assessment.

    EPA Science Inventory

    Recent challenges in risk assessment underscore the need to compare the results of toxicity and dose-response testing among a growing list of animal models and, possibly, an array of in vitro screening assays. Assays that quantify types of DNA damage that are directly relevant to...

  6. Toward a Molecular Equivalent Dose: Use of the Medaka Model in Comparative Risk Assessment.

    EPA Science Inventory

    Recent challenges in risk assessment underscore the need to compare the results of toxicity and dose-response testing among a growing list of animal models and, possibly, an array of in vitro screening assays. Assays that quantify types of DNA damage that are directly relevant to...

  7. Toxicokinetics to identify nonlinearities in dose-response and implications for risk assessment

    EPA Science Inventory

    For presentation at the 45th Annual Symposium of the Society of Toxicology of Canada. The meeting will be held on 4-5 December 2013 at the Ottawa Convention Centre. Toxicokinetics to identify nonlinearities in dose-response and implications for risk assessment. Rory Conolly, Offi...

  8. RESPIRATORY DOSE TO SUSCEPTIBLE POPULATIONS ASSESSED BY EXPOSURE AND DOSIMETRY STUDIES

    EPA Science Inventory

    Respiratory Dose to Susceptible Populations Assessed by Exposure and Dosimetry Studies

    Chong Kim1 and Ronald Williams2, 1USEPA National Health and Environmental Effects Research Laboratory and 2USEPA National Exposure Research Laboratory, RTP, NC.

    Rationale: Parti...

  9. RESPIRATORY DOSE TO SUSCEPTIBLE POPULATIONS ASSESSED BY EXPOSURE AND DOSIMETRY STUDIES

    EPA Science Inventory

    Respiratory Dose to Susceptible Populations Assessed by Exposure and Dosimetry Studies

    Chong Kim1 and Ronald Williams2, 1USEPA National Health and Environmental Effects Research Laboratory and 2USEPA National Exposure Research Laboratory, RTP, NC.

    Rationale: Parti...

  10. Toward a molecular equivalent dose: use of the medaka model in comparative risk assessment

    EPA Science Inventory

    Recent challenges in risk assessment underscore the need to compare the results of toxicity and dose-response testing among a growing list of animal models and, possibly, an array of in vitro screening assays. Assays that quantify types of DNA damage that are directly relevant to...

  11. Transcriptomic Dose-Response Analysis for Mode of Action and Risk Assessment

    EPA Science Inventory

    Microarray and RNA-seq technologies can play an important role in assessing the health risks associated with environmental exposures. The utility of gene expression data to predict hazard has been well documented. Early toxicogenomics studies used relatively high, single doses w...

  12. Transcriptomic Dose-Response Analysis for Mode of Action and Risk Assessment

    EPA Science Inventory

    Microarray and RNA-seq technologies can play an important role in assessing the health risks associated with environmental exposures. The utility of gene expression data to predict hazard has been well documented. Early toxicogenomics studies used relatively high, single doses w...

  13. Toxicokinetics to identify nonlinearities in dose-response and implications for risk assessment

    EPA Science Inventory

    For presentation at the 45th Annual Symposium of the Society of Toxicology of Canada. The meeting will be held on 4-5 December 2013 at the Ottawa Convention Centre. Toxicokinetics to identify nonlinearities in dose-response and implications for risk assessment. Rory Conolly, Offi...

  14. Toward a molecular equivalent dose: use of the medaka model in comparative risk assessment

    EPA Science Inventory

    Recent challenges in risk assessment underscore the need to compare the results of toxicity and dose-response testing among a growing list of animal models and, possibly, an array of in vitro screening assays. Assays that quantify types of DNA damage that are directly relevant to...

  15. Evaluation of Radiation Exposure to Staff and Environment Dose from [18F]-FDG in PET/CT and Cyclotron Center using Thermoluminescent Dosimetry.

    PubMed

    Zargan, S; Ghafarian, P; Shabestani Monfared, A; Sharafi, A A; Bakhshayeshkaram, M; Ay, M R

    2017-03-01

    PET/CT imaging using [18F]-FDG is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. Essential consideration must be taken for radiation staff due to high gamma radiation in PET/CT and cyclotron center. The aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in PET/CT and cyclotron center. 80 patients participated in this study. Thermoluminescence, electronic personal dosimeter and Geiger-Muller dosimeter were also utilized for measurement purpose. The mean annual equivalent organ dose for scanning operator with regard to lens of eyes, thyroid, breast and finger according to mean±SD value, were 0.262±0.044, 0.256±0.046, 0.257±0.040 and 0.316±0.118, respectively. The maximum and minimum estimated annual whole body doses were observed for injector and the chemist group with values of (3.98±0.021) mSv/yr and (1.64±0.014) mSv/yr, respectively. The observed dose rates were 5.67 µSv/h in uptake room at the distance of 0.5 meter from the patient whereas the value 4.94 and 3.08 µSv/h were recorded close to patient's head in PET/CT room and 3.5 meter from the reception desk. In this study, the injector staff and scanning operator received the first high level and second high level of radiation. This study confirmed that low levels of radiation dose were received by all radiation staff during PET/CT procedure using 18F-FDG due to efficient shielding and using trained radiation staff in PET/CT and cyclotron center of Masih Daneshvari hospital.

  16. Evaluation of Radiation Exposure to Staff and Environment Dose from [18F]-FDG in PET/CT and Cyclotron Center using Thermoluminescent Dosimetry

    PubMed Central

    Zargan, S.; Ghafarian, P.; Shabestani Monfared, A.; Sharafi, A.A.; Bakhshayeshkaram, M.; Ay, M.R.

    2017-01-01

    Background: PET/CT imaging using [18F]-FDG is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. Essential consideration must be taken for radiation staff due to high gamma radiation in PET/CT and cyclotron center. The aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in PET/CT and cyclotron center. Materials and Methods: 80 patients participated in this study. Thermoluminescence, electronic personal dosimeter and Geiger-Muller dosimeter were also utilized for measurement purpose. Results: The mean annual equivalent organ dose for scanning operator with regard to lens of eyes, thyroid, breast and finger according to mean±SD value, were 0.262±0.044, 0.256±0.046, 0.257±0.040 and 0.316±0.118, respectively. The maximum and minimum estimated annual whole body doses were observed for injector and the chemist group with values of (3.98±0.021) mSv/yr and (1.64±0.014) mSv/yr, respectively. The observed dose rates were 5.67 µSv/h in uptake room at the distance of 0.5 meter from the patient whereas the value 4.94 and 3.08 µSv/h were recorded close to patient’s head in PET/CT room and 3.5 meter from the reception desk. Conclusion: In this study, the injector staff and scanning operator received the first high level and second high level of radiation. This study confirmed that low levels of radiation dose were received by all radiation staff during PET/CT procedure using 18F-FDG due to efficient shielding and using trained radiation staff in PET/CT and cyclotron center of Masih Daneshvari hospital. PMID:28451574

  17. Assessing Temporal Behavior in LIDAR Point Clouds of Urban Environments

    NASA Astrophysics Data System (ADS)

    Schachtschneider, J.; Schlichting, A.; Brenner, C.

    2017-05-01

    Self-driving cars and robots that run autonomously over long periods of time need high-precision and up-to-date models of the changing environment. The main challenge for creating long term maps of dynamic environments is to identify changes and adapt the map continuously. Changes can occur abruptly, gradually, or even periodically. In this work, we investigate how dense mapping data of several epochs can be used to identify the temporal behavior of the environment. This approach anticipates possible future scenarios where a large fleet of vehicles is equipped with sensors which continuously capture the environment. This data is then being sent to a cloud based infrastructure, which aligns all datasets geometrically and subsequently runs scene analysis on it, among these being the analysis for temporal changes of the environment. Our experiments are based on a LiDAR mobile mapping dataset which consists of 150 scan strips (a total of about 1 billion points), which were obtained in multiple epochs. Parts of the scene are covered by up to 28 scan strips. The time difference between the first and last epoch is about one year. In order to process the data, the scan strips are aligned using an overall bundle adjustment, which estimates the surface (about one billion surface element unknowns) as well as 270,000 unknowns for the adjustment of the exterior orientation parameters. After this, the surface misalignment is usually below one centimeter. In the next step, we perform a segmentation of the point clouds using a region growing algorithm. The segmented objects and the aligned data are then used to compute an occupancy grid which is filled by tracing each individual LiDAR ray from the scan head to every point of a segment. As a result, we can assess the behavior of each segment in the scene and remove voxels from temporal objects from the global occupancy grid.

  18. Assessment of persistent and bioaccumulating chemicals in the aquatic environment.

    PubMed

    Calamari, Davide

    2002-12-27

    In recent years several national and international organizations have initiated actions to control the use and release of persistent, bioaccumulative and toxic substances (PBTs). Consequently, a number of criteria have been proposed for the classification of these parameters. The scientific bases for PBTs assessment has grown a great deal over the last decades. In some specific areas reliable predictive capability exists while in other areas considerable uncertainty is still present. This paper will briefly point out the achievements and limitations of the knowledge on persistence and bioaccumulation with reference to the aquatic environment.

  19. The Effect of Dose Rate on Composite Durability When Exposed to a Simulated Long-Term Lunar Radiation Environment

    NASA Technical Reports Server (NTRS)

    Rojdev, Kristina; O'Rourke, Mary Jane; Hill, Charles; Nutt, Steven; Atwell, William

    2011-01-01

    Human exploration of space beyond low Earth orbit (LEO) requires a safe living and working environment for crew. Composite materials are one type of material being investigated by NASA as a multi-functional structural approach to habitats for long-term use in space or on planetary surfaces with limited magnetic fields and atmosphere. These materials provide high strength with the potential for decreased weight and increased radiation protection of crew and electronics when compared with conventional aluminum structures. However, these materials have not been evaluated in a harsh radiation environment, as would be experienced outside of LEO or on a planetary surface. Thus, NASA has been investigating the durability of select composite materials in a long-term radiation environment. Previously, NASA exposed composite samples to a simulated, accelerated 30-year radiation treatment and tensile stresses similar to those of a habitat pressure vessel. The results showed evidence of potential surface oxidation and enhanced cross-linking of the matrix. As a follow-on study, we performed the same accelerated exposure alongside an exposure with a decreased dose rate. The slower dose ]rate is comparable to a realistic scenario, although still accelerated. Strain measurements were collected during exposure and showed that with a fastdose rate, the strain decreased with time, but with a slow ]dose rate, the strain increased with time. After the radiation exposures, samples were characterized via tensile tests, flexure tests, Fourier Transform Infrared Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC). The results of these tests will be discussed.

  20. What does not kill them makes them stronger: larval environment and infectious dose alter mosquito potential to transmit filarial worms

    PubMed Central

    Breaux, Jennifer A.; Schumacher, Molly K.; Juliano, Steven A.

    2014-01-01

    For organisms with complex life cycles, larval environments can modify adult phenotypes. For mosquitoes and other vectors, when physiological impacts of stressors acting on larvae carry over into the adult stage they may interact with infectious dose of a vector-borne pathogen, producing a range of phenotypes for vector potential. Investigation of impacts of a common source of stress, larval crowding and intraspecific competition, on adult vector interactions with pathogens may increase our understanding of the dynamics of pathogen transmission by mosquito vectors. Using Aedes aegypti and the nematode parasite Brugia pahangi, we demonstrate dose dependency of fitness effects of B. pahangi infection on the mosquito, as well as interactions between competitive stress among larvae and infectious dose for resulting adults that affect the physiological and functional ability of mosquitoes to act as vectors. Contrary to results from studies on mosquito–arbovirus interactions, our results suggest that adults from crowded larvae may limit infection better than do adults from uncrowded controls, and that mosquitoes from high-quality larval environments are more physiologically and functionally capable vectors of B. pahangi. Our results provide another example of how the larval environment can have profound effects on vector potential of resulting adults. PMID:24827444

  1. What does not kill them makes them stronger: larval environment and infectious dose alter mosquito potential to transmit filarial worms.

    PubMed

    Breaux, Jennifer A; Schumacher, Molly K; Juliano, Steven A

    2014-07-07

    For organisms with complex life cycles, larval environments can modify adult phenotypes. For mosquitoes and other vectors, when physiological impacts of stressors acting on larvae carry over into the adult stage they may interact with infectious dose of a vector-borne pathogen, producing a range of phenotypes for vector potential. Investigation of impacts of a common source of stress, larval crowding and intraspecific competition, on adult vector interactions with pathogens may increase our understanding of the dynamics of pathogen transmission by mosquito vectors. Using Aedes aegypti and the nematode parasite Brugia pahangi, we demonstrate dose dependency of fitness effects of B. pahangi infection on the mosquito, as well as interactions between competitive stress among larvae and infectious dose for resulting adults that affect the physiological and functional ability of mosquitoes to act as vectors. Contrary to results from studies on mosquito-arbovirus interactions, our results suggest that adults from crowded larvae may limit infection better than do adults from uncrowded controls, and that mosquitoes from high-quality larval environments are more physiologically and functionally capable vectors of B. pahangi. Our results provide another example of how the larval environment can have profound effects on vector potential of resulting adults.

  2. Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans.

    PubMed

    Guberina, Nika; Suntharalingam, Saravanabavaan; Naßenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian

    2016-10-01

    The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use.

  3. Robust tissue classification for reproducible wound assessment in telemedicine environments

    NASA Astrophysics Data System (ADS)

    Wannous, Hazem; Treuillet, Sylvie; Lucas, Yves

    2010-04-01

    In telemedicine environments, a standardized and reproducible assessment of wounds, using a simple free-handled digital camera, is an essential requirement. However, to ensure robust tissue classification, particular attention must be paid to the complete design of the color processing chain. We introduce the key steps including color correction, merging of expert labeling, and segmentation-driven classification based on support vector machines. The tool thus developed ensures stability under lighting condition, viewpoint, and camera changes, to achieve accurate and robust classification of skin tissues. Clinical tests demonstrate that such an advanced tool, which forms part of a complete 3-D and color wound assessment system, significantly improves the monitoring of the healing process. It achieves an overlap score of 79.3 against 69.1% for a single expert, after mapping on the medical reference developed from the image labeling by a college of experts.

  4. Assessment of acute concussion in the combat environment.

    PubMed

    Kelly, Mark P; Coldren, Rodney L; Parish, Robert V; Dretsch, Michael N; Russell, Michael L

    2012-06-01

    Despite the prevalence of concussion in soldiers deployed to Iraq and Afghanistan, neuropsychological tests used to assist in concussion management have not been validated on the battlefield. This study evaluated the validity of the Automated Neuropsychological Assessment Metrics (ANAM) in the combat environment. Cases meeting criteria for concussion, healthy controls, and injured controls were assessed. Soldiers were administered the ANAM, traditional neuropsychological tests, and a background questionnaire. Cases were enrolled within 72 h of concussion. Cases exhibited poorer performance than controls on all ANAM subtests, with significant differences on simple reaction time (SRT), procedural reaction time (PRT), code substitution, and matching to sample (p<.001). Discriminant ability of scores on SRT and PRT subtests was 71%, which improved to 76% when pre-deployment baseline scores were available. An exploratory clinical decision tool incorporating ANAM scores and symptoms improved discriminant ability to 81%. Results provide initial validation of the ANAM for detecting acute effects of battlefield concussion.

  5. Variations in semiconductor device response in a medium-energy x-ray dose-enhancing environment

    SciTech Connect

    Beutler, D.E.; Fleetwood, D.M.; Beezhold, W.; Knott, D.; Lorence, L.J. Jr.; Draper, B.L.

    1987-12-01

    The authors performed a series of experiments to investigate the response of semiconductor devices to medium-energy x-ray irradiation under conditions in which dose-enhancement effects are very important. They find that the response of MOS capacitors to the same ''dose-enhanced'' radiation depends not only on the increased dose, but also on the incident radiation spectra, device temperature and processing, and/or oxide thickness and electric field. In many cases, these dependencies cannot be explained simply in terms of existing knowledge of basic mechanisms of radiation effects on MOS devices (for example, electron-hole recombination and hole transport and trapping), or by present Monte Carlo electron/photon transport codes such as the Integrated Tiger Series (ITS). In addition, the response of semiconductor diodes to the ''dose-enhanced'' radiation appears to be qualitatively different from that of MOS capacitors, and differs markedly in value from the ITS code predictions. These results demonstrate that an improved understanding of semiconductor device response to ''enhanced'' radiation is needed to assure simulation fidelity of tests of devices to be used in dose-enhancing environments.

  6. Development and Datametric Properties of a Scale Measuring Students' Perceptions of the Classroom Assessment Environment

    ERIC Educational Resources Information Center

    Alkharusi, Hussain

    2011-01-01

    Each classroom has its own assessment environment perceived by the students and springs from the teacher's assessment practices. Although students' perceptions of the assessment environment may influence their achievement-related outcomes, little attention has been given to the measurement of perceived classroom assessment environment. This study…

  7. A user friendly database for use in ALARA job dose assessment

    SciTech Connect

    Zodiates, A.M.; Willcock, A.

    1995-03-01

    The pressurized water reactor (PWR) design chosen for adoption by Nuclear Electric plc was based on the Westinghouse Standard Nuclear Unit Power Plant (SNUPPS). This design was developed to meet the United Kingdom requirements and these improvements are embodied in the Sizewell B plant which will start commercial operation in 1994. A user-friendly database was developed to assist the station in the dose and ALARP assessments of the work expected to be carried out during station operation and outage. The database stores the information in an easily accessible form and enables updating, editing, retrieval, and searches of the information. The database contains job-related information such as job locations, number of workers required, job times, and the expected plant doserates. It also contains the means to flag job requirements such as requirements for temporary shielding, flushing, scaffolding, etc. Typical uses of the database are envisaged to be in the prediction of occupational doses, the identification of high collective and individual dose jobs, use in ALARP assessments, setting of dose targets, monitoring of dose control performance, and others.

  8. Deterministic vs. probabilistic analyses to identify sensitive parameters in dose assessment using RESRAD.

    PubMed

    Kamboj, Sunita; Cheng, Jing-Jy; Yu, Charley

    2005-05-01

    The dose assessments for sites containing residual radioactivity usually involve the use of computer models that employ input parameters describing the physical conditions of the contaminated and surrounding media and the living and consumption patterns of the receptors in analyzing potential doses to the receptors. The precision of the dose results depends on the precision of the input parameter values. The identification of sensitive parameters that have great influence on the dose results would help set priorities in research and information gathering for parameter values so that a more precise dose assessment can be conducted. Two methods of identifying site-specific sensitive parameters, deterministic and probabilistic, were compared by applying them to the RESRAD computer code for analyzing radiation exposure for a residential farmer scenario. The deterministic method has difficulty in evaluating the effect of simultaneous changes in a large number of input parameters on the model output results. The probabilistic method easily identified the most sensitive parameters, but the sensitivity measure of other parameters was obscured. The choice of sensitivity analysis method would depend on the availability of site-specific data. Generally speaking, the deterministic method would identify the same set of sensitive parameters as the probabilistic method when 1) the baseline values used in the deterministic method were selected near the mean or median value of each parameter and 2) the selected range of parameter values used in the deterministic method was wide enough to cover the 5th to 95th percentile values from the distribution of that parameter.

  9. Detection and original dose assessment of egg powders subjected to gamma irradiation by using ESR technique

    NASA Astrophysics Data System (ADS)

    Aydın, Talat

    2015-09-01

    ESR (electron spin resonance) techniques were applied for detection and original dose estimation to radiation-processed egg powders. The un-irradiated (control) egg powders showed a single resonance line centered at g=2.0086±0.0005, 2.0081±0.0005, 2.0082±0.0005 (native signal) for yolk, white and whole egg, respectively. Irradiation induced at least one additional intense singlet overlapping to the control signal and caused a significant increase in signal intensity without any changes in spectral patterns. Responses of egg powders to different gamma radiation doses in the range 0-10 kGy were examined. The stability of the radiation-induced ESR signal of irradiated egg powders were investigated over a storage period of about 5 months. Additive reirradiation of the egg powders produces a reproducible dose response function, which can be used to assess the initial dose by back-extrapolation. The additive dose method gives an estimation of the original dose within ±12% at the end of the 720 h storage period.

  10. Monte Carlo Assessments of Absorbed Doses to the Hands of Radiopharmaceutical Workers Due to Photon Emitters

    SciTech Connect

    Ilas, Dan; Eckerman, Keith F; Karagiannis, Harriet

    2009-01-01

    This paper describes the characterization of radiation doses to the hands of nuclear medicine technicians resulting from the handling of radiopharmaceuticals. Radiation monitoring using ring dosimeters indicates that finger dosimeters that are used to show compliance with applicable regulations may overestimate or underestimate radiation doses to the skin depending on the nature of the particular procedure and the radionuclide being handled. To better understand the parameters governing the absorbed dose distributions, a detailed model of the hands was created and used in Monte Carlo simulations of selected nuclear medicine procedures. Simulations of realistic configurations typical for workers handling radiopharmaceuticals were performedfor a range of energies of the source photons. The lack of charged-particle equilibrium necessitated full photon-electron coupled transport calculations. The results show that the dose to different regions of the fingers can differ substantially from dosimeter readings when dosimeters are located at the base of the finger. We tried to identify consistent patterns that relate the actual dose to the dosimeter readings. These patterns depend on the specific work conditions and can be used to better assess the absorbed dose to different regions of the exposed skin.

  11. Assessment of radiation dose in nuclear cardiovascular imaging using realistic computational models

    SciTech Connect

    Xie, Tianwu; Lee, Choonsik; Bolch, Wesley E.; Zaidi, Habib

    2015-06-15

    Purpose: Nuclear cardiology plays an important role in clinical assessment and has enormous impact on the management of a variety of cardiovascular diseases. Pediatric patients at different age groups are exposed to a spectrum of radiation dose levels and associated cancer risks different from those of adults in diagnostic nuclear medicine procedures. Therefore, comprehensive radiation dosimetry evaluations for commonly used myocardial perfusion imaging (MPI) and viability radiotracers in target population (children and adults) at different age groups are highly desired. Methods: Using Monte Carlo calculations and biological effects of ionizing radiation VII model, we calculate the S-values for a number of radionuclides (Tl-201, Tc-99m, I-123, C-11, N-13, O-15, F-18, and Rb-82) and estimate the absorbed dose and effective dose for 12 MPI radiotracers in computational models including the newborn, 1-, 5-, 10-, 15-yr-old, and adult male and female computational phantoms. Results: For most organs, {sup 201}Tl produces the highest absorbed dose whereas {sup 82}Rb and {sup 15}O-water produce the lowest absorbed dose. For the newborn baby and adult patient, the effective dose of {sup 82}Rb is 48% and 77% lower than that of {sup 99m}Tc-tetrofosmin (rest), respectively. Conclusions: {sup 82}Rb results in lower effective dose in adults compared to {sup 99m}Tc-labeled tracers. However, this advantage is less apparent in children. The produced dosimetric databases for various radiotracers used in cardiovascular imaging, using new generation of computational models, can be used for risk-benefit assessment of a spectrum of patient population in clinical nuclear cardiology practice.

  12. Assessment of radiation dose in nuclear cardiovascular imaging using realistic computational models

    PubMed Central

    Xie, Tianwu; Lee, Choonsik; Bolch, Wesley E.; Zaidi, Habib

    2015-01-01

    Purpose: Nuclear cardiology plays an important role in clinical assessment and has enormous impact on the management of a variety of cardiovascular diseases. Pediatric patients at different age groups are exposed to a spectrum of radiation dose levels and associated cancer risks different from those of adults in diagnostic nuclear medicine procedures. Therefore, comprehensive radiation dosimetry evaluations for commonly used myocardial perfusion imaging (MPI) and viability radiotracers in target population (children and adults) at different age groups are highly desired. Methods: Using Monte Carlo calculations and biological effects of ionizing radiation VII model, we calculate the S-values for a number of radionuclides (Tl-201, Tc-99m, I-123, C-11, N-13, O-15, F-18, and Rb-82) and estimate the absorbed dose and effective dose for 12 MPI radiotracers in computational models including the newborn, 1-, 5-, 10-, 15-yr-old, and adult male and female computational phantoms. Results: For most organs, 201Tl produces the highest absorbed dose whereas 82Rb and 15O-water produce the lowest absorbed dose. For the newborn baby and adult patient, the effective dose of 82Rb is 48% and 77% lower than that of 99mTc-tetrofosmin (rest), respectively. Conclusions: 82Rb results in lower effective dose in adults compared to 99mTc-labeled tracers. However, this advantage is less apparent in children. The produced dosimetric databases for various radiotracers used in cardiovascular imaging, using new generation of computational models, can be used for risk-benefit assessment of a spectrum of patient population in clinical nuclear cardiology practice. PMID:26127049

  13. Age-dependent dose assessment of 226Ra from bottled water intake.

    PubMed

    Bronzovic, Maja; Marovic, Gordana

    2005-05-01

    Water may present a source of prolonged exposure to naturally occurring radionuclides. One of the most frequently occurring radionuclides in natural mineral and spring waters is 226Ra and its decay products. The contribution of drinking water to the total exposure is very small, at about 5% of the average effective dose attributable annually to natural background radiation, but that exposure contributes to the risk of adverse health consequences. In this study the mean values of 226Ra concentration determined in natural mineral and spring bottled waters range from 6 to 412 mBq L(-1), which is in accord with Croatian legislation. 226Ra effective doses per year from spring water consumption range up to 86 microSv, while 226Ra effective doses per year from mineral water consumption show much higher values. The highest 226Ra effective doses per year from mineral waters consumption, which are up to seven times higher than the dose recommended by WHO (100 microSv), were found in infants and teens. Based on this study, drinking of certain brands of bottled mineral water is not recommended for these age groups because assessed 226Ra effective doses per year exceed the recommended limits. From other research it is known that testosterone appears in elevated concentration during these life periods and affects bone calcification. Therefore, testosterone could affect the retention of 226Ra into the bone. To make more precise conclusions further research is necessary. Adults and especially elderly people are much less susceptible to the presence of 226Ra. According to the results obtained in this study, 226Ra effective doses per year assessed for these age groups were considerably lower (i.e., 10 microSv).

  14. Preliminary assessment of the dose to the interventional radiologist in fluoro-CT-guided procedures.

    PubMed

    Pereira, M F; Alves, J G; Sarmento, S; Santos, J A M; Sousa, M J; Gouvêa, M; Oliveira, A D; Cardoso, J V; Santos, L M

    2011-03-01

    A preliminary assessment of the occupational dose to the intervention radiologist received in fluoroscopy computerised tomography (CT) used to guide the collection of lung and bone biopsies is presented. The main aim of this work was to evaluate the capability of the reading system as well as of the available whole-body (WB) and extremity dosemeters used in routine monthly monitoring periods to measure per procedure dose values. The intervention radiologist was allocated 10 WB detectors (LiF: Mg, Ti, TLD-100) placed at chest and abdomen levels above and below the lead apron, and at both right and left arms, knees and feet. A special glove was developed with casings for the insertion of 11 extremity detectors (LiF:Mg, Cu, P, TLD-100H) for the identification of the most highly exposed fingers. The H(p)(10) dose values received above the lead apron (ranged 0.20-0.02 mSv) depend mainly on the duration of the examination and on the placement of physician relative to the beam, while values below the apron are relatively low. The left arm seems to receive a higher dose value. H(p)(0.07) values to the hand (ranged 36.30-0.06 mSv) show that the index, middle and ring fingers are the most highly exposed. In this study, the wrist dose was negligible compared with the finger dose. These results are preliminary and further studies are needed to better characterise the dose assessment in CT fluoroscopy.

  15. Radiation dose assessment in a 320-detector-row CT scanner used in cardiac imaging

    SciTech Connect

    Goma, Carles; Ruiz, Agustin; Jornet, Nuria; Latorre, Artur; Pallerol, Rosa M.; Carrasco, Pablo; Eudaldo, Teresa; Ribas, Montserrat

    2011-03-15

    Purpose: In the present era of cone-beam CT scanners, the use of the standardized CTDI{sub 100} as a surrogate of the idealized CTDI is strongly discouraged and, consequently, so should be the use of the dose-length product (DLP) as an estimate of the total energy imparted to the patient. However, the DLP is still widely used as a reference quantity to normalize the effective dose for a given scan protocol mainly because the CTDI{sub 100} is an easy-to-measure quantity. The aim of this article is therefore to describe a method for radiation dose assessment in large cone-beam single axial scans, which leads to a straightforward estimation of the total energy imparted to the patient. The authors developed a method accessible to all medical physicists and easy to implement in clinical practice in an attempt to update the bridge between CT dosimetry and the estimation of the effective dose. Methods: The authors used commercially available material and a simple mathematical model. The method described herein is based on the dosimetry paradigm introduced by the AAPM Task Group 111. It consists of measuring the dose profiles at the center and the periphery of a long body phantom with a commercial solid-state detector. A weighted dose profile is then calculated from these measurements. To calculate the CT dosimetric quantities analytically, a Gaussian function was fitted to the dose profile data. Furthermore, the Gaussian model has the power to condense the z-axis information of the dose profile in two parameters: The single-scan central dose, f(0), and the width of the profile, {sigma}. To check the energy dependence of the solid-state detector, the authors compared the dose profiles to measurements made with a small volume ion chamber. To validate the overall method, the authors compared the CTDI{sub 100} calculated analytically to the measurement made with a 100 mm pencil ion chamber. Results: For the central and weighted dose profiles, the authors found a good

  16. Assessment of organ absorbed doses and estimation of effective doses from pediatric anthropomorphic phantom measurements for multi-detector row CT with and without automatic exposure control.

    PubMed

    Brisse, Hervé J; Robilliard, Magalie; Savignoni, Alexia; Pierrat, Noelle; Gaboriaud, Geneviève; De Rycke, Yann; Neuenschwander, Sylvia; Aubert, Bernard; Rosenwald, Jean-Claude

    2009-10-01

    This study was designed to measure organ absorbed doses from multi-detector row computed tomography (MDCT) on pediatric anthropomorphic phantoms, calculate the corresponding effective doses, and assess the influence of automatic exposure control (AEC) in terms of organ dose variations. Four anthropomorphic phantoms (phantoms represent the equivalent of a newborn, 1-, 5-, and 10-y-old child) were scanned with a four-channel MDCT coupled with a z-axis-based AEC system. Two CT torso protocols were compared: a first protocol without AEC and constant tube current-time product and a second protocol with AEC using age-adjusted noise indices. Organ absorbed doses were monitored by thermoluminescent dosimeters (LiF: Mg, Cu, P). Effective doses were calculated according to the tissue weighting factors of the International Commission on Radiological Protection (). For fixed mA acquisitions, organ doses normalized to the volume CT dose index in a 16-cm head phantom (CTDIvol16) ranged from 0.6 to 1.5 and effective doses ranged from 8.4 to 13.5 mSv. For the newborn-equivalent phantom, the AEC-modulated scan showed almost no significant dose variation compared to the fixed mA scan. For the 1-, 5- and 10-y equivalent phantoms, the use of AEC induced a significant dose decrease on chest organs (ranging from 61 to 31% for thyroid, 37 to 21% for lung, 34 to 17% for esophagus, and 39 to 10% for breast). However, AEC also induced a significant dose increase (ranging from 28 to 48% for salivary glands, 22 to 51% for bladder, and 24 to 70% for ovaries) related to the high density of skull base and pelvic bones. These dose increases should be considered before using AEC as a dose optimization tool in children.

  17. Development of softcopy environment for primary color banding visibility assessment

    NASA Astrophysics Data System (ADS)

    Min, Byungseok; Pizlo, Zygmunt; Allebach, Jan P.

    2008-01-01

    Fine-pitch banding is one of the most unwanted artifacts in laser electrophotographic (EP) printers. It is perceived as a quasiperiodic fluctuation in the process direction. Therefore, it is essential for printer vendors to know how banding is perceived by humans in order to improve print quality. Monochrome banding has been analyzed and assessed by many researchers; but there is no literature that deals with the banding of color laser printers as measured from actual prints. The study of color banding is complicated by the fact that the color banding signal is physically defined in a three-dimensional color space, while banding perception is described in a one-dimensional sense such as more banding or less banding. In addition, the color banding signal arises from the independent contributions of the four primary colorant banding signals. It is not known how these four distinct signals combine to give rise to the perception of color banding. In this paper, we develop a methodology to assess the banding visibility of the primary colorant cyan based on human visual perception. This is our first step toward studying the more general problem of color banding in combinations of two or more colorants. According to our method, we print and scan the cyan test patch, and extract the banding profile as a one dimensional signal so that we can freely adjust the intensity of banding. Thereafter, by exploiting the pulse width modulation capability of the laser printer, the extracted banding profile is used to modulate a pattern consisting of periodic lines oriented in the process direction, to generate extrinsic banding. This avoids the effect of the halftoning algorithm on the banding. Furthermore, to conduct various banding assessments more efficiently, we also develop a softcopy environment that emulates a hardcopy image on a calibrated monitor, which requires highly accurate device calibration throughout the whole system. To achieve the same color appearance as the hardcopy

  18. Assessing reference staff competency in the electronic environment.

    PubMed

    Munson, Kurt I; Walton, Linda J

    2004-01-01

    This paper shows how the Galter Health Sciences Library of Northwestern University's Feinberg School of Medicine developed and implemented a program to assess reference staff competencies for assisting users in the electronic environment after completing a new training program. The first phase was a year-long assessment of reference questions to identify the types of questions received at the desk. Next, a training program for reference was developed and implemented with an emphasis on answering the most common questions identified such as remote access, access privileges, holdings information, and database searching. The program included individualized instruction on library policies, electronic resources, access restrictions, and troubleshooting. The next phase was to create instruments to test staff competencies in answering questions after training. Based on the scores, additional training was individualized and provided to the appropriate staff member to enhance their skills where needed. The training system that was developed has proven to be effective as most staff scored better than 92% on initial testing. As a result, library management can be certain that users' questions are being answered correctly and that the staff has the skills required to work in an electronic environment.

  19. Computational Pollutant Environment Assessment from Propulsion-System Testing

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See; McConnaughey, Paul; Chen, Yen-Sen; Warsi, Saif

    1996-01-01

    An asymptotic plume growth method based on a time-accurate three-dimensional computational fluid dynamics formulation has been developed to assess the exhaust-plume pollutant environment from a simulated RD-170 engine hot-fire test on the F1 Test Stand at Marshall Space Flight Center. Researchers have long known that rocket-engine hot firing has the potential for forming thermal nitric oxides, as well as producing carbon monoxide when hydrocarbon fuels are used. Because of the complex physics involved, most attempts to predict the pollutant emissions from ground-based engine testing have used simplified methods, which may grossly underpredict and/or overpredict the pollutant formations in a test environment. The objective of this work has been to develop a computational fluid dynamics-based methodology that replicates the underlying test-stand flow physics to accurately and efficiently assess pollutant emissions from ground-based rocket-engine testing. A nominal RD-170 engine hot-fire test was computed, and pertinent test-stand flow physics was captured. The predicted total emission rates compared reasonably well with those of the existing hydrocarbon engine hot-firing test data.

  20. Assessment of the occupational eye lens dose for clinical staff in interventional radiology, cardiology and neuroradiology.

    PubMed

    Omar, Artur; Kadesjö, Nils; Palmgren, Charlotta; Marteinsdottir, Maria; Segerdahl, Tony; Fransson, Annette

    2017-03-20

    In accordance with recommendations by the International Commission on Radiological Protection, the current European Basic Safety Standards has adopted a reduced occupational eye lens dose limit of 20 mSv yr(-1). The radiation safety implications of this dose limit is of concern for clinical staff that work with relatively high dose x-ray angiography and interventional radiology. Presented in this work is a thorough assessment of the occupational eye lens dose based on clinical measurements with active personal dosimeters worn by staff during various types of procedures in interventional radiology, cardiology and neuroradiology. Results are presented in terms of the estimated equivalent eye lens dose for various medical professions. In order to compare the risk of exceeding the regulatory annual eye lens dose limit for the widely different clinical situations investigated in this work, the different medical professions were separated into categories based on their distinct work pattern: staff that work (a) regularly beside the patient, (b) in proximity to the patient and (c) typically at a distance from the patient. The results demonstrate that the risk of exceeding the annual eye lens dose limit is of concern for staff category (a), i.e. mainly the primary radiologist/cardiologist. However, the results also demonstrate that the risk can be greatly mitigated if radiation protection shields are used in the clinical routine. The results presented in this work cover a wide range of clinical situations, and can be used as a first indication of the risk of exceeding the annual eye lens dose limit for staff at other medical centres.

  1. Assessment of knowledge, attitude, and practices on fixed dose combinations among postgraduate dental students

    PubMed Central

    Vinnakota, Narayana R.; Krishna, V.; Viswanath, V.; Ahmed, Zaheer; Shaik, Kamal S.; Boppana, Naveen K.

    2016-01-01

    Aim: To assess the knowledge, attitude, and practices of fixed dose combination drugs among postgraduate dental students. Materials and Methods: A cross-sectional study was carried out among postgraduate dental students of dental colleges in coastal Andhra Pradesh. Three colleges were randomly selected and students of all the three years were included. Data was collected from the specialities of oral medicine and radiology, oral surgery, endodontics, pedodontics, periodontics, and public health dentistry. The total sample was 90 postgraduate students; informed consent was obtained from the participants, and a pretested questionnaire was distributed to them. Data was analyzed using the Statistical Package for the Social Sciences version 20 software. Results: Out of 90 postgraduates, 33 were males and 57 were females. Thirty-five percent were aware of the essential medical list (EML), among them 11% were from oral medicine and radiology and 6.7% were from pedodontics. However, most of them were unaware of the number of fixed dose combination drugs present in the World Health Organization EML. None of them were able to name at least a single banned fixed dose combination drug. Most of them were unaware of the advantages and disadvantages of using fixed dose combination drugs. Amoxicillin with clavulanic acid was the most common drug prescribed by students (73.3%) followed by ofloxacin with ornidazole (54.4%), ibuprofen with paracetamol (53.3%), and sulfamethoxazole with trimethoprim (6%). Most of them were unaware of the rationality in using fixed dose combination drugs. Common sources of information were medical representatives 43 (47.8%), internet 39 (43.3%), and 12 (13.3%) reported using WHO EML. Conclusion: There is an urgent need to improve knowledge on the rationality for using fixed dose combination, EML, and banned fixed dose combination in India to the promote rational use of fixed dose combination. PMID:28217544

  2. Assessment of knowledge, attitude, and practices on fixed dose combinations among postgraduate dental students.

    PubMed

    Vinnakota, Narayana R; Krishna, V; Viswanath, V; Ahmed, Zaheer; Shaik, Kamal S; Boppana, Naveen K

    2016-12-01

    To assess the knowledge, attitude, and practices of fixed dose combination drugs among postgraduate dental students. A cross-sectional study was carried out among postgraduate dental students of dental colleges in coastal Andhra Pradesh. Three colleges were randomly selected and students of all the three years were included. Data was collected from the specialities of oral medicine and radiology, oral surgery, endodontics, pedodontics, periodontics, and public health dentistry. The total sample was 90 postgraduate students; informed consent was obtained from the participants, and a pretested questionnaire was distributed to them. Data was analyzed using the Statistical Package for the Social Sciences version 20 software. Out of 90 postgraduates, 33 were males and 57 were females. Thirty-five percent were aware of the essential medical list (EML), among them 11% were from oral medicine and radiology and 6.7% were from pedodontics. However, most of them were unaware of the number of fixed dose combination drugs present in the World Health Organization EML. None of them were able to name at least a single banned fixed dose combination drug. Most of them were unaware of the advantages and disadvantages of using fixed dose combination drugs. Amoxicillin with clavulanic acid was the most common drug prescribed by students (73.3%) followed by ofloxacin with ornidazole (54.4%), ibuprofen with paracetamol (53.3%), and sulfamethoxazole with trimethoprim (6%). Most of them were unaware of the rationality in using fixed dose combination drugs. Common sources of information were medical representatives 43 (47.8%), internet 39 (43.3%), and 12 (13.3%) reported using WHO EML. There is an urgent need to improve knowledge on the rationality for using fixed dose combination, EML, and banned fixed dose combination in India to the promote rational use of fixed dose combination.

  3. Assessment of eye lens doses for workers during interventional radiology procedures.

    PubMed

    Urboniene, A; Sadzeviciene, E; Ziliukas, J

    2015-07-01

    The assessment of eye lens doses for workers during interventional radiology (IR) procedures was performed using a new eye lens dosemeter. In parallel, the results of routine individual monitoring were analysed and compared with the results obtained from measurements with a new eye lens dosemeter. The eye lens doses were assessed using Hp(3) measured at the level of the eyes and were compared with Hp(10) measured with the whole-body dosemeter above the lead collar. The information about use of protective measures, the number of performed interventional procedures per month and their fluoroscopy time was also collected. The assessment of doses to the lens of the eye was done for 50 IR workers at 9 Lithuanian hospitals for the period of 2012-2013. If the use of lead glasses is not taken into account, the estimated maximum annual dose equivalent to the lens of the eye was 82 mSv. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Beyond dose assessment: using risk with full disclosure of uncertainty in public and scientific communication.

    PubMed

    Hoffman, F Owen; Kocher, David C; Apostoaei, A Iulian

    2011-11-01

    Evaluations of radiation exposures of workers and the public traditionally focus on assessments of radiation dose, especially annual dose, without explicitly evaluating the health risk associated with those exposures, principally the risk of radiation-induced cancer. When dose is the endpoint of an assessment, opportunities to communicate the significance of exposures are limited to comparisons with dose criteria in regulations, doses due to natural background or medical x-rays, and doses above which a statistically significant increase of disease has been observed in epidemiologic studies. Risk assessment generally addresses the chance (probability) that specific diseases might be induced by past, present, or future exposure. The risk of cancer per unit dose will vary depending on gender, age, exposure type (acute or chronic), and radiation type. It is not uncommon to find that two individuals with the same effective dose will have substantially different risks. Risk assessment has shown, for example, that: (a) medical exposures to computed tomography scans have become a leading source of future risk to the general population, and that the risk would be increased above recently published estimates if the incidence of skin cancer and the increased risk from exposure to x-rays compared with high-energy photons were taken into account; (b) indoor radon is a significant contributor to the baseline risk of lung cancer, particularly among people who have never smoked; and (c) members of the public who were exposed in childhood to I in fallout from atmospheric nuclear weapons tests and were diagnosed with thyroid cancer later in life would frequently meet criteria established for federal compensation of cancers experienced by energy workers and military participants at atmospheric weapons tests. Risk estimation also enables comparisons of impacts of exposures to radiation and chemical carcinogens and other hazards to life and health. Communication of risk with

  5. Analysis of finite dose dermal absorption data: Implications for dermal exposure assessment

    PubMed Central

    Frasch, H Frederick; Dotson, G Scott; Bunge, Annette L; Chen, Chen-Peng; Cherrie, John W; Kasting, Gerald B; Kissel, John C; Sahmel, Jennifer; Semple, Sean; Wilkinson, Simon

    2014-01-01

    A common dermal exposure assessment strategy estimates the systemic uptake of chemical in contact with skin using the fixed fractional absorption approach: the dermal absorbed dose is estimated as the product of exposure and the fraction of applied chemical that is absorbed, assumed constant for a given chemical. Despite the prominence of this approach there is little guidance regarding the evaluation of experiments from which fractional absorption data are measured. An analysis of these experiments is presented herein, and limitations to the fixed fractional absorption approach are discussed. The analysis provides a set of simple algebraic expressions that may be used in the evaluation of finite dose dermal absorption experiments, affording a more data-driven approach to dermal exposure assessment. Case studies are presented that demonstrate the application of these tools to the assessment of dermal absorption data. PMID:23715085

  6. The use of mode of action information in risk assessment: quantitative key events/dose-response framework for modeling the dose-response for key events.

    PubMed

    Simon, Ted W; Simons, S Stoney; Preston, R Julian; Boobis, Alan R; Cohen, Samuel M; Doerrer, Nancy G; Fenner-Crisp, Penelope A; McMullin, Tami S; McQueen, Charlene A; Rowlands, J Craig

    2014-08-01

    The HESI RISK21 project formed the Dose-Response/Mode-of-Action Subteam to develop strategies for using all available data (in vitro, in vivo, and in silico) to advance the next-generation of chemical risk assessments. A goal of the Subteam is to enhance the existing Mode of Action/Human Relevance Framework and Key Events/Dose Response Framework (KEDRF) to make the best use of quantitative dose-response and timing information for Key Events (KEs). The resulting Quantitative Key Events/Dose-Response Framework (Q-KEDRF) provides a structured quantitative approach for systematic examination of the dose-response and timing of KEs resulting from a dose of a bioactive agent that causes a potential adverse outcome. Two concepts are described as aids to increasing the understanding of mode of action-Associative Events and Modulating Factors. These concepts are illustrated in two case studies; 1) cholinesterase inhibition by the pesticide chlorpyrifos, which illustrates the necessity of considering quantitative dose-response information when assessing the effect of a Modulating Factor, that is, enzyme polymorphisms in humans, and 2) estrogen-induced uterotrophic responses in rodents, which demonstrate how quantitative dose-response modeling for KE, the understanding of temporal relationships between KEs and a counterfactual examination of hypothesized KEs can determine whether they are Associative Events or true KEs.

  7. New model for assessing dose, dose rate, and temperature sensitivity of radiation-induced absorption in glasses

    SciTech Connect

    Gilard, Olivier; Quadri, Gianandrea; Caussanel, Matthieu; Duval, Herve; Reynaud, Francois

    2010-11-15

    A new theoretical approach is proposed to explain the dose, dose rate and temperature sensitivity of the radiation-induced absorption (RIA) in glasses. In this paper, a {beta}{sup th}-order dispersive kinetic model is used to simulate the growth of the density of color centers in irradiated glasses. This model yields an explanation for the power-law dependence on dose and dose rate usually observed for the RIA in optical fibers. It also leads to an Arrhenius-like relationship between the RIA and the glass temperature during irradiation. With a very limited number of adjustable parameters, the model succeeds in explaining, with a good agreement, the RIA growth of two different optical fiber references over wide ranges of dose, dose rate and temperature.

  8. Human Health Risk Assessment: A case study application of principles in dose response assessment

    EPA Science Inventory

    This case study application workshop will build on fundamental concepts and techniques in risk assessment presented and archived at previous TRAC meeting workshops. Practical examples from publicly available, peer reviewed risk assessments will be used as teaching aids. Course ...

  9. An assessment of the reliability of dose coefficients for intakes of radionuclides by members of the public.

    PubMed

    Puncher, M

    2014-09-01

    This paper summarises work undertaken on behalf of the Environment Agency for England to quantify uncertainties resulting from internal exposures to a number of radionuclides considered significant because of their anthropogenic origin, namely: (238)U, (226)Ra, (239)Pu, (241)Am, (137)Cs, (90)Sr, (131)I, (129)I and (3)H. Uncertainties in the biokinetic models that are used to calculate the retention and excretion of radionuclides are derived in order to calculate distributions of effective dose per unit intake following their inhalation or ingestion by members of the UK public. The central values and ranges of the distributions are used to inform the derivation of uncertainty factors (UFs) for the different dose coefficients, which can be used to assess reliability. These represent uncertainties inherent in the structures of the biokinetic models and their parameter values. The inferred UF values are typically around 2-3 for ingestion and 2-6 for inhalation for all age groups, and are comparable to UF values inferred from published studies. It is instructive to consider these ranges alongside the likely levels of exposure that are expected from the radionuclides considered (the microsievert range) and the dose limit of planned exposures for members of the public (1000 μSv).

  10. 3D delivered dose assessment using a 4DCT-based motion model

    PubMed Central

    Cai, Weixing; Hurwitz, Martina H.; Williams, Christopher L.; Dhou, Salam; Berbeco, Ross I.; Seco, Joao; Mishra, Pankaj; Lewis, John H.

    2015-01-01

    reconstructed from kV and MV projections compared to the ground truth, which is clinically comparable to 4DCT (0.093%). For the second XCAT phantom that has an irregular breathing pattern, the errors are 0.81% and 1.75% for kV and MV reconstructions, both of which are better than that of 4DCT (4.01%). In the case of real patient, although it is impossible to obtain the actual delivered dose, the dose estimation is clinically reasonable and demonstrates differences between 4DCT and MV reconstruction-based dose estimates. Conclusions: With the availability of kV or MV projection images, the proposed approach is able to assess delivered doses for all respiratory phases during treatment. Compared to the planning dose based on 4DCT, the dose estimation using reconstructed 3D fluoroscopic images was as good as 4DCT for regular respiratory pattern and was a better dose estimation for the irregular respiratory pattern. PMID:26127043

  11. 3D delivered dose assessment using a 4DCT-based motion model

    SciTech Connect

    Cai, Weixing; Hurwitz, Martina H.; Williams, Christopher L.; Dhou, Salam; Berbeco, Ross I.; Mishra, Pankaj E-mail: jhlewis@lroc.harvard.edu; Lewis, John H. E-mail: jhlewis@lroc.harvard.edu; Seco, Joao

    2015-06-15

    reconstructed from kV and MV projections compared to the ground truth, which is clinically comparable to 4DCT (0.093%). For the second XCAT phantom that has an irregular breathing pattern, the errors are 0.81% and 1.75% for kV and MV reconstructions, both of which are better than that of 4DCT (4.01%). In the case of real patient, although it is impossible to obtain the actual delivered dose, the dose estimation is clinically reasonable and demonstrates differences between 4DCT and MV reconstruction-based dose estimates. Conclusions: With the availability of kV or MV projection images, the proposed approach is able to assess delivered doses for all respiratory phases during treatment. Compared to the planning dose based on 4DCT, the dose estimation using reconstructed 3D fluoroscopic images was as good as 4DCT for regular respiratory pattern and was a better dose estimation for the irregular respiratory pattern.

  12. Internal dose assessment -- Operation Crossroads. Technical report, 11 January 1984-15 April 1985

    SciTech Connect

    Phillips, J.; Klemm, J.; Goetz, J.

    1985-10-30

    The radiation dose commitment to ten body organs/parts, due to inhalation of resuspended nuclear contaminants from target ships exposed to the underwater burst (Test Baker) is determined for personnel who worked on the ships during and after Operation CROSSROADS. Four representative ships, INDEPENDENCE, NEW YORK, PENSACOLA and SALT LAKE CITY, are examined for the personnel activities associated with post-BAKER reboarding. Additionally, the dose due to internal emitters is assessed for personnel who unloaded ammunition from twenty target ships at Kwajalein, and for shipyard workers exposed to eight of the higher intensity ships at Pearl Harbor, Puget Sound, and San Francisco Naval Shipyards. For almost all activities, fifty-year bone dose commitments are less than 0.15 rem from any annual period of exposure.

  13. [Comparative assessment of the doses received by patients during radiodiagnosis of the urinary system].

    PubMed

    Nemiro, E A; Viderman, M; Gubatova, D Ia; Gushak, V; Krastynia, A K; Lidova, L N; Trunova, N I

    1989-01-01

    The authors present some literature data, estimated data and results of phantom measurements in order to give comparative assessment of radiation exposure of patients during radio-contrast and radionuclide investigation of the urinary system. The importance and distribution of doses absorbed by organs and tissues (HT) and effective equivalent doses (HE) in two most commonly used radiodiagnostic methods were studied. In radiocontrast urography (RCUG) the maximum values of tissue doses were noted for the female gonads and the organs adjacent to the kidneys (the liver, pancreas, etc.). However, in radionuclide investigation (RNI) of the urinary system HT reached its maximum directly in the organs under study (the kidneys and urinary bladder). Considerable difference in the patients' HE was also revealed. In view of the above data, RNI is recommended for clinical use even at the first stage of diagnosis of diseases of the urinary system. Diagnostic information obtained with RNI makes it possible to give up RCUG in some cases.

  14. In vivo assessment of catheter positioning accuracy and prolonged irradiation time on liver tolerance dose after single-fraction 192Ir high-dose-rate brachytherapy

    PubMed Central

    2011-01-01

    Background To assess brachytherapy catheter positioning accuracy and to evaluate the effects of prolonged irradiation time on the tolerance dose of normal liver parenchyma following single-fraction irradiation with 192 Ir. Materials and methods Fifty patients with 76 malignant liver tumors treated by computed tomography (CT)-guided high-dose-rate brachytherapy (HDR-BT) were included in the study. The prescribed radiation dose was delivered by 1 - 11 catheters with exposure times in the range of 844 - 4432 seconds. Magnetic resonance imaging (MRI) datasets for assessing irradiation effects on normal liver tissue, edema, and hepatocyte dysfunction, obtained 6 and 12 weeks after HDR-BT, were merged with 3D dosimetry data. The isodose of the treatment plan covering the same volume as the irradiation effect was taken as a surrogate for the liver tissue tolerance dose. Catheter positioning accuracy was assessed by calculating the shift between the 3D center coordinates of the irradiation effect volume and the tolerance dose volume for 38 irradiation effects in 30 patients induced by catheters implanted in nearly parallel arrangement. Effects of prolonged irradiation were assessed in areas where the irradiation effect volume and tolerance dose volume did not overlap (mismatch areas) by using a catheter contribution index. This index was calculated for 48 irradiation effects induced by at least two catheters in 44 patients. Results Positioning accuracy of the brachytherapy catheters was 5-6 mm. The orthogonal and axial shifts between the center coordinates of the irradiation effect volume and the tolerance dose volume in relation to the direction vector of catheter implantation were highly correlated and in first approximation identically in the T1-w and T2-w MRI sequences (p = 0.003 and p < 0.001, respectively), as were the shifts between 6 and 12 weeks examinations (p = 0.001 and p = 0.004, respectively). There was a significant shift of the irradiation effect towards

  15. Task 3 Report - PCBs in the Environment Near the Oak Ridge Reservation - A Reconstruction of Historical Doses and Health Risks

    SciTech Connect

    Price, Paul S; Widner, Thomas; Bonnevie, Nancy; Schmidt, Charlie; McCrodden-Hamblen, Jane; Vantaggio, Joanne; Gwinn, Patrick

    1999-07-01

    This report presents the results of an in-depth assessment of historical releases of polychlorinated biphenyls (PCBs) from the Oak Ridge Reservation (ORR) and risks of adverse health effects in local populations. The study was conducted by ChemRisk, a service of McLaren/Hart, Inc., for the Tennessee Department of Health. The project team (1) investigated releases of PCBs from the government sites, (2) evaluated PCB levels in environmental media in the area, (3) described releases of PCBs from other sources in the area, and (4) evaluated potential human exposures and health impacts associated with the historical presence of these contaminants in the environment. Beginning in the 1940s, PCBs were used extensively on the ORR and throughout the U.S. as a fire retardant in electrical components. PCBs were also used as cutting fluids for lubrication and cooling during metal working operations. Using information specific to the ORR, the project team estimated health risks for five off-site populations: (1) farm families that raised beef, dairy cattle, and vegetables on the flood plain of East Fork Poplar Creek (EFPC); (2) individuals who may have purchased beef and milk from cattle raised in the EFPC flood plain; (3) commercial and recreational fish consumers; (4) individuals that may have consumed turtles; and (5) users of surface water for recreation. Noteworthy features of the study include a two-dimensional analysis of uncertainty and variability in the non-cancer risk estimates and an assessment of the uncertainty in PCB toxicology thresholds. Conservative estimates of cancer risks from the ORR releases of PCBs to consumers of fish from Watts Bar Reservoir and the Clinch River range from less than 1 in a 1,000,000 to 2 in 10,000. Three or less excess cases of cancer would be expected to occur among individuals who consumed fish from these local waters since the 1940's. Persons who consumed large amounts of fish from the Clinch R. and Watts Bar were also at risk from

  16. An assessment of galactic cosmic radiation quality considering heavy ion track structures within the cellular environment

    NASA Astrophysics Data System (ADS)

    Craven, P. A.; Rycroft, M. J.

    Beyond the magnetic influence of the Earth, the flux of galactic cosmic radiation (GCR) represents a radiological concern for long-term manned space missions. Current concepts of radiation quality and equivalent dose are inadequate for accurately specifying the relative biological ``efficiency'' of low doses of such heavily ionising radiations, based as they are on the single parameter of Linear Energy Transfer (LET). Such methods take no account of the mechanisms, nor of the highly inhomogeneous spatial structure, of energy deposition in radiation tracks. DNA damage in the cell nucleus, which ultimately leads to the death or transformation of the cell, is usually initiated by electrons liberated from surrounding molecules by the incident projectile ion. The characteristics of these emitted ``delta-rays'', dependent primarily upon the charge and velocity of the ion, are considered in relation to an idealised representation of the cellular environment. Theoretically calculated delta-ray energy spectra are multiplied by a series of weighting algorithms designed to represent the potential for DNA insult in this environment, both in terms of the quantity and quality of damage. By evaluating the resulting curves, and taking into account the energy spectra of heavy ions in space, a relative measure of the biological relevance of the most abundant GCR species is obtained, behind several shielding configurations. It is hoped that this method of assessing the radiation quality of galactic cosmic rays will be of value when considering the safety of long-term manned space missions.

  17. An automated system for assessing cognitive function in any environment

    NASA Astrophysics Data System (ADS)

    Wesnes, Keith A.

    2005-05-01

    The Cognitive Drug Research (CDR) computerized assessment system has been in use in worldwide clinical trials for over 20 years. It is a computer based system which assesses core aspects of human cognitive function including attention, information, working memory and long-term memory. It has been extensively validated and can be performed by a wide range of clinical populations including patients with various types of dementia. It is currently in worldwide use in clinical trials to evaluate new medicines, as well as a variety of programs involving the effects of age, stressors illnesses and trauma upon human cognitive function. Besides being highly sensitive to drugs which will impair or improve function, its utility has been maintained over the last two decades by constantly increasing the number of platforms upon which it can operate. Besides notebook versions, the system can be used on a wrist worn device, PDA, via tht telephone and over the internet. It is the most widely used automated cognitive function assessment system in worldwide clinical research. It has dozens of parallel forms and requires little training to use or administer. The basic development of the system wil be identified, and the huge databases (normative, patient population, drug effects) which have been built up from hundreds of clinical trials will be described. The system is available for use in virtually any environment or type of trial.

  18. The road to linearity: why linearity at low doses became the basis for carcinogen risk assessment.

    PubMed

    Calabrese, Edward J

    2009-03-01

    This article assesses the historical foundations of how linearity at low dose became accepted by the scientific/regulatory communities. While the threshold model was used in the 1920s/1930s in establishing radiation health standards, its foundations were challenged by the genetics community who argued that radiation induced mutations in reproductive cells followed a linear response, were cumulative and deleterious. Scientific foundations of linearity for gonadal mutations were based on non-conclusive evidence as well as not being conducted at low doses. Following years of debate, leaders in the genetics community participated in the U.S. National Academy of Sciences (NAS) (1956) Biological Effects of Atomic Radiation (BEAR) BEAR I Committee, getting their perspectives accepted, incorporating linearity for radiation-induced mutational effects in risk assessment. Overtime the concept of linearity was generalized to include somatic effects induced by radiation based on a protectionist philosophy. This affected the course of radiation-induced and later chemically-induced carcinogen risk assessment. Acceptance of linearity at low dose from chemical carcinogens was strongly influenced by the NAS Safe Drinking Water Committee report of 1977 which provided the critical guidance to the U.S. EPA to adopt linear at low dose modeling for risk assessment for chemical carcinogens with little supportive data, much of which has been either discredited or seriously weakened over the past 3 decades. Nonetheless, there has been little practical change of regulatory policy concerning carcinogen risk assessment. These observations suggest that while scientific disciplines are self correcting, that regulatory 'science' fails to display the same self-correcting mechanism despite contradictory data.

  19. The monetary value of the averted dose for public exposure assessed by the willingness to pay.

    PubMed

    Katona, Tünde; Kanyár, Béla; Eged, Katalin; Kis, Zoltan; Nényei, Arpád; Bodnár, Robert

    2003-05-01

    The monetary value of the unit averted collective dose at an individual reference dose (as alpha(base)-value) and the aversion against the high individual exposure were assessed by the WTP (Willingness To Pay) method. The original questionnaire and methodology were developed by the CEPN, France, for specialists in the nuclear field. Modifications to the questionnaire were introduced in 2000 to take into account the Hungarian aspects. In 2001, the questionnaire was further modified for use with the public in Hungary. The present paper refers to the results from the most recent studies on public exposure. The questionnaire was provided to 118 persons living in four different regions of Hungary, one near the U-mining site, one near a nuclear power plant, and two others far away from nuclear affected sites. Conversion of the questionnaire to be understandable by the public involved intensive modifications both in form and content. Only 83 to 86 respondents provided usable answers to questions related to the monetary value of the averted dose and the aversion coefficient. The alpha(base)-value was determined from the statistical value of life assessed by the willingness to pay of the respondents for the risk of fatal cancer averted. The mathematical form used to assess the aversion coefficient was a power function with respect to the individual dose, as already introduced in our earlier papers. The advantage of the power function is that the aversion coefficient is independent of the individual reference dose. According to the current results, the mean value of the lognormally distributed alpha-value at the individual reference dose (alpha(base)) takes 10,000 US dollars (person Sv)(-1) with large confidence bounds. The alpha(base)-value is about 50% higher than the alpha(base)-value estimated among the radiation specialists in Hungary, but 5-10 times less than the values obtained in highly developed countries like in France. The normally distributed aversion coefficient

  20. Cosmic-ray-induced radiation environment and dose to man for low-orbit space applications

    SciTech Connect

    Sandmeier, H.A.; Hansen, G.E.; Battat, M.E.; O'Brien, K.

    1981-09-01

    Neutrons and photons resulting from the interaction of galactic cosmic rays with the material of an orbiting satellite or an orbiting space station at an altitude of some few hundreds of kilometers, and below the level of the radiation belts, have been calculated as a function of geomagnetic latitude and solar activity level. The photon and neutron leakage currents from the top of the atmosphere have been computed. The radiation dose-equivalent rate to an unshielded astronaut has also been calculated. The maximum dose-equivalent rate, near the magnetic poles, was 2 mrem/h. In deep space this would amount to 18 rem/y, indicating that for a prolonged stay in space, shielding would be needed.

  1. Radiation therapy for stage IIA and IIB testicular seminoma: peripheral dose calculations and risk assessments

    NASA Astrophysics Data System (ADS)

    Mazonakis, Michalis; Berris, Theocharris; Lyraraki, Efrossyni; Damilakis, John

    2015-03-01

    This study was conducted to calculate the peripheral dose to critical structures and assess the radiation risks from modern radiotherapy for stage IIA/IIB testicular seminoma. A Monte Carlo code was used for treatment simulation on a computational phantom representing an average adult. The initial treatment phase involved anteroposterior and posteroanaterior modified dog-leg fields exposing para-aortic and ipsilateral iliac lymph nodes followed by a cone-down phase for nodal mass irradiation. Peripheral doses were calculated using different modified dog-leg field dimensions and an extended conventional dog-leg portal. The risk models of the BEIR-VII report and ICRP-103 were combined with dosimetric calculations to estimate the probability of developing stochastic effects. Radiotherapy for stage IIA seminoma with a target dose of 30 Gy resulted in a range of 23.0-603.7 mGy to non-targeted peripheral tissues and organs. The corresponding range for treatment of stage IIB disease to a cumulative dose of 36 Gy was 24.2-633.9 mGy. A dose variation of less than 13% was found by altering the field dimensions. Radiotherapy with the conventional instead of the modern modified dog-leg field increased the peripheral dose up to 8.2 times. The calculated heart doses of 589.0-632.9 mGy may increase the risk for developing cardiovascular diseases whereas the testicular dose of more than 231.9 mGy may lead to a temporary infertility. The probability of birth abnormalities in the offspring of cancer survivors was below 0.13% which is much lower than the spontaneous mutation rate. Abdominoplevic irradiation may increase the lifetime intrinsic risk for the induction of secondary malignancies by 0.6-3.9% depending upon the site of interest, patient’s age and tumor dose. Radiotherapy for stage IIA/IIB seminoma with restricted fields and low doses is associated with an increased morbidity. These data may allow the definition of a risk-adapted follow-up scheme for long

  2. Radiation therapy for stage IIA and IIB testicular seminoma: peripheral dose calculations and risk assessments.

    PubMed

    Mazonakis, Michalis; Berris, Theocharris; Lyraraki, Efrossyni; Damilakis, John

    2015-03-21

    This study was conducted to calculate the peripheral dose to critical structures and assess the radiation risks from modern radiotherapy for stage IIA/IIB testicular seminoma. A Monte Carlo code was used for treatment simulation on a computational phantom representing an average adult. The initial treatment phase involved anteroposterior and posteroanaterior modified dog-leg fields exposing para-aortic and ipsilateral iliac lymph nodes followed by a cone-down phase for nodal mass irradiation. Peripheral doses were calculated using different modified dog-leg field dimensions and an extended conventional dog-leg portal. The risk models of the BEIR-VII report and ICRP-103 were combined with dosimetric calculations to estimate the probability of developing stochastic effects. Radiotherapy for stage IIA seminoma with a target dose of 30 Gy resulted in a range of 23.0-603.7 mGy to non-targeted peripheral tissues and organs. The corresponding range for treatment of stage IIB disease to a cumulative dose of 36 Gy was 24.2-633.9 mGy. A dose variation of less than 13% was found by altering the field dimensions. Radiotherapy with the conventional instead of the modern modified dog-leg field increased the peripheral dose up to 8.2 times. The calculated heart doses of 589.0-632.9 mGy may increase the risk for developing cardiovascular diseases whereas the testicular dose of more than 231.9 mGy may lead to a temporary infertility. The probability of birth abnormalities in the offspring of cancer survivors was below 0.13% which is much lower than the spontaneous mutation rate. Abdominoplevic irradiation may increase the lifetime intrinsic risk for the induction of secondary malignancies by 0.6-3.9% depending upon the site of interest, patient's age and tumor dose. Radiotherapy for stage IIA/IIB seminoma with restricted fields and low doses is associated with an increased morbidity. These data may allow the definition of a risk-adapted follow-up scheme for long

  3. Realistic retrospective dose assessments to members of the public around Spanish nuclear facilities.

    PubMed

    Jiménez, M A; Martín-Valdepeñas, J M; García-Talavera, M; Martín-Matarranz, J L; Salas, M R; Serrano, J I; Ramos, L M

    2011-11-01

    In the frame of an epidemiological study carried out in the influence areas around the Spanish nuclear facilities (ISCIII-CSN, 2009. Epidemiological Study of The Possible Effect of Ionizing Radiations Deriving from The Operation of Spanish Nuclear Fuel Cycle Facilities on The Health of The Population Living in Their Vicinity. Final report December 2009. Ministerio de Ciencia e Innovación, Instituto de Salud Carlos III, Consejo de Seguridad Nuclear. Madrid. Available from: http://www.csn.es/images/stories/actualidad_datos/especiales/epidemiologico/epidemiological_study.pdf), annual effective doses to public have been assessed by the Spanish Nuclear Safety Council (CSN) for over 45 years using a retrospective realistic-dose methodology. These values are compared with data from natural radiation exposure. For the affected population, natural radiation effective doses are in average 2300 times higher than effective doses due to the operation of nuclear installations (nuclear power stations and fuel cycle facilities). When considering the impact on the whole Spanish population, effective doses attributable to nuclear facilities represent in average 3.5×10(-5)mSv/y, in contrast to 1.6mSv/y from natural radiation or 1.3mSv/y from medical exposures.

  4. Internal dose assessment data management system for a large population of Pu workers.

    PubMed

    Bertelli, L; Miller, G; Little, T; Guilmette, R A; Glasser, S M

    2007-01-01

    This paper describes the design and implementation of the Los Alamos National Laboratory (LANL) dose assessment (DA) data system. Dose calculations for the most important radionuclides at LANL, namely plutonium, americium, uranium and tritium, are performed through the Microsoft Access DA database. DA includes specially developed forms and macros that perform a variety of tasks, such as retrieving bioassay data, launching the FORTRAN internal dosimetry applications and displaying dose results in the form of text summaries and plots. The DA software involves the following major processes: (1) downloading of bioassay data from a remote data source, (2) editing local and remote databases, (3) setting up and carrying out internal dose calculations using the UF code or the ID code, (3) importing results of the dose calculations into local results databases, (4) producing a secondary database of 'official results' and (5) automatically creating and e-mailing reports. The software also provides summary status and reports of the pending DAs, which are useful for managing the cases in process.

  5. Assessment of CpTi Surface Properties after Nitrogen Ion Implantation with Various Doses and Energies

    NASA Astrophysics Data System (ADS)

    Fulazzaky, Mohamad Ali; Ali, Nurdin; Samekto, Haryanti; Ghazali, Mohd Imran

    2012-11-01

    Nitrogen ion implantation is one of the surface modification techniques used for increasing corrosion resistance of commercially pure titanium (CpTi). The nitrogen ion implanted CpTi in various doses markedly changes the corrosion resistance. Still the effect of nitrogen ion implantation on the CpTi at different energies needs to be verified. This study uses different methods to assess the CpTi surface properties after nitrogen ion implantation in various doses and energy. Surface hardness of the CpTi increases with an increase of the dose and decreases with an increase of the energy. The precipitation of the TiN increases with an increase of the nitrogen dose, and no formation of the Ti2N phase clearly appears. Corrosion resistance of the CpTi specimens can be upgraded to some extent after their surfaces are modified, implanting nitrogen ions at 100 keV by increasing dose. The optimum surface properties of the implanted CpTi are analyzed to contribute to materials science technology.

  6. Actual versus prescribed timing of lovastatin doses assessed by electronic compliance monitoring.

    PubMed

    Kruse, W; Nikolaus, T; Rampmaier, J; Weber, E; Schlierf, G

    1993-01-01

    The objective of the study was to compare compliance with and the hypocholesterolaemic effect of lovastatin given once daily as a morning or an evening dose. Twenty-four out-patients with familial hypercholesterolaemia were randomly assigned to receive placebo first, then lovastatin 20 mg, to be taken once daily for 4 weeks, either with the breakfast or evening meal, in a single-blind fashion. Drug compliance was assessed by pill counts and continuous electronic monitoring. Two compliance parameters were evaluated, consumption, defined as percentage of prescribed doses taken, and time compliance, the percentage of total dosing events recorded within defined intervals (6.00-10.00 h, and 17.00-21.00 h), for the morning and evening regimes. Both regimes satisfactorily reduced the total and LDL-cholesterol concentrations, and there was no significant difference in the extent of the reductions. Pill counts overestimated compliance, as revealed by the monitoring method. The times of actual consumption of doses by the patients often differed from that prescribed, predominantly in patients who were told to take the evening dose. Partial time compliance may have confounded the efficacy of the drugs. Electronic compliance monitoring appears to be particularly useful in chronopharmacological studies.

  7. Study of blood forming organ dose as a function of proton environment

    NASA Technical Reports Server (NTRS)

    Khandelwal, G. S.

    1974-01-01

    It is demonstrated that a dosimeter which consists of four ion chambers, each with different wall thickness, is able to reproduce the BFO dose with reasonable accuracy. This generalized dosimetric system is only slightly more complex than dosimeters in current use. This preliminary development had two built-in assumptions; the isotropicity of the radiation and the neglect of nuclear reaction effects. Only the nuclear reaction effects have been calculated.

  8. Multiple Methods for Assessing the Dose to Skin Exposed to Radioactive Contamination.

    PubMed

    Dubeau, J; Heinmiller, B E; Corrigan, M

    2017-04-28

    There is the possibility for a worker at a nuclear installation, such as a nuclear power reactor, a fuel production facility or a medical facility, to come in contact with radioactive contaminants. When such an event occurs, the first order of business is to care for the worker by promptly initiating a decontamination process. Usually, the radiation protection personnel performs a G-M pancake probe measurement of the contamination in situ and collects part or all of the radioactive contamination for further laboratory analysis. The health physicist on duty must then perform, using the available information, a skin dose assessment that will go into the worker's permanent dose record. The contamination situations are often complex and the dose assessment can be laborious. This article compares five dose assessment methods that involve analysis, new technologies and new software. The five methods are applied to 13 actual contamination incidents consisting of direct skin contact, contamination on clothing and contamination on clothing in the presence of an air gap between the clothing and the skin. This work shows that, for the cases studied, the methods provided dose estimates that were usually within 12% (1σ) of each other, for those cases where absolute activity information for every radionuclide was available. One method, which relies simply on a G-M pancake probe measurement, appeared to be particularly useful in situations where a contamination sample could not be recovered for laboratory analysis. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Historical development and evolution of EPRI's post-closure dose assessment of potential releases to the biosphere from the proposed HLW repository at Yucca Mountain.

    PubMed

    Smith, Graham; Kozak, Matthew W

    2011-12-01

    This paper describes the development and evolution of the Electric Power Research Institute's (EPRI) post-closure dose assessment for potential releases of radionuclides from the proposed High Level Waste repository at Yucca Mountain. The starting point for this work was the 1995 publication of Technical Bases for Yucca Mountain Standards by the Commission on Geosciences, Environment and Resources of the National Research Council. This report proposed the development and application of an individual risk-based standard for releases from the repository to replace the existing one, which was based on radionuclide release limits. This in turn implied the development and application of methods to assess radiation doses to humans. Accordingly, EPRI produced a methodology for such dose assessment as part of its Total System Performance Assessment program for the proposed Yucca Mountain repository site. The methodology initially addressed releases via groundwater and then releases associated with extrusive igneous events. The methodology was updated and applied over the following years to take account of regulatory developments, changes in estimates of the source term to the biosphere, peer review through international model comparison exercises, new site generic data, and new data concerning conditions at the point of compliance in Amargosa Valley. The main outputs were Biosphere Dose Conversion Factors, which relate radionuclide levels in environmental media to the annual individual doses to a member of a hypothetical critical group and to the regulator-defined Reasonably Maximally Exposed Individual. Most recently, consideration has been given to uncertainty in the dose estimates based on a probabilistic analysis. The paper provides a perspective on the evolution of the dose assessments in response to the developments listed above.

  10. Outdoor solar UVA dose assessment with EBT2 radiochromic film using spectrophotometer and densitometer measurements.

    PubMed

    Abukassem, I; Bero, M A

    2015-04-01

    Direct measurements of solar ultraviolet radiations (UVRs) have an important role in the protection of humans against UVR hazard. This work presents simple technique based on the application of EBT2 GAFCHROMIC(®) film for direct solar UVA dose assessment. It demonstrates the effects of different parts of the solar spectrum (UVB, visible and infrared) on performed UVA field measurements and presents the measurement uncertainty budget. The gradient of sunlight exposure level permitted the authors to establish the mathematical relationships between the measured solar UVA dose and two measured quantities: the first was the changes in spectral absorbance at the wavelength 633 nm (A633) and the second was the optical density (OD). The established standard relations were also applied to calculate the solar UVA dose variations during the whole day; 15 min of exposure each hour between 8:00 and 17:00 was recorded. Results show that both applied experimental methods, spectrophotometer absorbance and densitometer OD, deliver comparable figures for EBT2 solar UVA dose assessment with relative uncertainty of 11% for spectral absorbance measurements and 15% for OD measurements. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Dose assessment, radioecology, and community interaction at former nuclear test sites

    SciTech Connect

    Robison, W.L.

    1994-11-01

    The US conducted a nuclear testing program at Bikini and Enewetak Atolls in the Marshall Islands from 1946 through 1958. A total of 66 nuclear devices were tested--23 at Bikini Atoll (total yield of 77 megatons) and 43 at Enewetak Atoll (total yield of 33 megatons). This resulted in contamination of many of the islands at each atoll. The BRAVO test (yield 15 megatons) on March 1, 1954 contaminated several atolls to the east of Bikini Atoll some of which were inhabited. The author has conducted an experimental, monitoring, and dose assessment program at atolls in the northern Marshall Islands for the past 20 years. The goals have been to: (1) determine the radiological conditions at the atolls; (2) provide dose assessments for resettlement options and alternate living patterns; (3) develop and evaluate remedial measures to reduce the dose to people reinhabiting the atolls; and (4) discuss the results with each of the communities and the Republic of the Marshall Islands government officials to help them understand the data as a basis for resettlement decisions. The remaining radionuclides at the atolls that contribute any significant dose are {sup 137}Cs, {sup 90}Sr, {sup 239+240}Pu, and {sup 241}Am.

  12. Cancer risk assessment: Optimizing human health through linear dose-response models.

    PubMed

    Calabrese, Edward J; Shamoun, Dima Yazji; Hanekamp, Jaap C

    2015-07-01

    This paper proposes that generic cancer risk assessments be based on the integration of the Linear Non-Threshold (LNT) and hormetic dose-responses since optimal hormetic beneficial responses are estimated to occur at the dose associated with a 10(-4) risk level based on the use of a LNT model as applied to animal cancer studies. The adoption of the 10(-4) risk estimate provides a theoretical and practical integration of two competing risk assessment models whose predictions cannot be validated in human population studies or with standard chronic animal bioassay data. This model-integration reveals both substantial protection of the population from cancer effects (i.e. functional utility of the LNT model) while offering the possibility of significant reductions in cancer incidence should the hormetic dose-response model predictions be correct. The dose yielding the 10(-4) cancer risk therefore yields the optimized toxicologically based "regulatory sweet spot". Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Efficient Assessment of the Environment for Integral Urban Water Management

    NASA Astrophysics Data System (ADS)

    Rost, Grit; Londong, Jörg

    2015-04-01

    required subjects/disciplines implies first sight expert knowledge or provided open access data. In the case of the need for a more detailed screening the next steps consist of scientifically based analysis and legal statutory analysis. Indexes (indicators) or benchmarks for each assessment scale will be summarized and linked to suitable measures. The trans- and interdisciplinary approach makes sure that technical, informative and administrative measures will be involved. A rating between the current situation and the determined target situation will help for effective derivation of measures. Conclusion: The claim of the stepwise assessment is to make the data possible to handle, and to summarize the knowledge of expert's effective environmental assessment methods. The universe, comprehensive assessment will be feasible by using the toolbox. The toolbox will be a planning tool for sustainable urban water management and closed loop recycling water management. GWP, INBO (2009) A Handbook for Integrated Water Resources Management in Basins. 104. Karthe D, Heldt S, Rost G, et al (2014) Modular Concept for Municipal Water Management in the Kharaa River Basin, Mongolia. Environ. Sci. Price RK, Vojinović Z (2011) Urban Hydroinformatics Data, Models and Decision Support for Integrated Urban Water Management. 520. Rost G, Londong J, Dietze S, Osor G (2013) Integrated urban water management - an adapted management approach for planning and implementing measures: Case study area Darkhan , Kharaa catchment, Mongolia. Submitt to Environ Earth Sci 19. Stäudel J, Schalkwyk B Van, Gibbens M (2014) Methods and strategies for community-based enhancement & up-scaling of sanitation & waste management in peri-urban areas in South Africa. SANO. Rhombos-Verlag, Weimar, pp 1-13

  14. Promoting a bicycle-friendly environment: community assessment and action.

    PubMed

    Sharpe, Patricia; Burroughs, Erika; Hooker, Steven; Pekuri, Linda; Blumberg, Catherine; Hutto, Brent

    2011-01-01

    Researchers and community coalition members collected survey data and used it to guide production of an educational video promoting a bicycle-friendly environment. Telephone and mailed surveys were conducted among bicyclists and motorists for needs assessment. A sample of 173 bicyclists completed a mailed survey (response rate of 87.0%), and a sample of 801 motorists completed a telephone survey (response rate of 42.1%). Findings guided video production. Most motorists understood that bicyclists have a right to ride in the road, but about one half believed bicyclists create a hazard, even when they follow traffic laws. Bicyclists expressed safety concerns and felt threatened by motorists. Both motorists' and bicyclists' knowledge of traffic rules varied across the items. This project illustrates how community members can apply research findings to an educational video of high quality with local relevance. The leadership from community members in making the video set the foundation for local ownership.

  15. Indifference curves as a tool for environment impact assessment.

    PubMed

    Srivastava, Anjali; Ganguly, Arpita

    2010-01-01

    Use of indifference curves, defined as functionality between development index and pollution load to evaluate environmental impact, is proposed. Existing Battelle environmental evaluation methodology is subjective in its approach. The use of indifference curves lends a more objective approach to environment assessment methodology. The extent of environmental damage we are prepared to accept, for a development, can be explained by Willingness to Pay and Willingness to Accept approach. The application of proposed approach has been demonstrated taking an example of Power plant set up in forest area. The curves clearly show that cost of EMP considering mitigation of ecological damage is higher than the EMP mitigating impacts of air and water pollution only. The example stresses the need for willingness to accept along with willingness to pay.

  16. Assessment of a University Campus Food Environment, California, 2015

    PubMed Central

    DeGreef, Kelsey; Fishler, Madison; Gipson, Rachel; Koyano, Kelly; Neill, Dawn B.

    2016-01-01

    Introduction University campuses offer an opportunity to study the extent to which modifying the food environment influences eating, but in-depth characterizations of campus food environments are needed to identify potential targets for intervention. The objective of this project was to describe the availability, accessibility, and quality of healthful food choices in dining venues and food stores at or near a public, 4-year university in California. Methods Trained assessors used the Nutrition Environment Measures Survey for campus dining (NEMS-CD) to evaluate all 18 campus dining venues, and NEMS for stores (NEMS-S) to evaluate 2 on-campus and 37 off-campus food stores. We calculated prevalence of healthful and unhealthful constructs (eg, availability of selected food items, presence of signage encouraging healthful eating, pricing options that encourage healthful eating), based on the NEMS and compared scores across different types of venues. Results NEMS-CD scores ranged from 4 to 47 (mean [SD], 26.0 [14.4]) out of a possible maximum score of 97; 12% of entrées and 36% of main dish salads served in these venues were classified as healthful. NEMS-S score for the 2 on-campus food stores (24 for both) was intermediate between off-campus convenience stores (mean [SD], 12.0 [5.3]) and grocery/supermarket stores (mean [SD], 31.1 [10.0]), with a possible maximum score of 54. Conclusion Standardized environmental evaluation provides insights into both positive and negative aspects of campus community food venues. Environmental assessment identifies potential targets for modification and baseline data for designing and implementing action-oriented research aimed at improving the campus food environment’s support of healthful food choices for college students. PMID:26851337

  17. Risk assessment in an R D environment: Lessons learned

    SciTech Connect

    Howard, H. )

    1993-01-01

    The US Department of Energy (DOE) is undergoing what can be called a [open quotes]cultural change.[close quotes] This paper presents some of the good and bad experiences of that change in the areas of risk analysis and assessment. Its focus is on the research lab environment. Some of the problems encountered at the Los Alamos National Laboratory (LANL) include rapidly evolving and radically changing research initiatives, rapid-fire budget swings, and the ever-changing priorities that all of us face in a rapidly changing world. New construction projects suffer because of illogical funding procedures that do not allow for the inclusion of risk assessment activities at their appropriate time. What to do with existing facilities which are difficult and expensive to upgrade to today's standards is also a large-scale problem. With the rapidly changing missions throughout the DOE complex, organizations must be prepared to quickly cope with safety analysis requirements far more sophisticated and voluminous than just a few short years ago. The Savannah River Site (SRS), operated for the DOE by the Westinghouse Savannah River Company, has been a pioneer in the development of methods required to perform quantitative risk assessments for a wide variety of facilities in a cost-effective manner. Industrial, nuclear, and chemical hazards are analyzed. The process begins with the identification of the hazards and continues with the accidents that result in releasing the hazard to a recipient, quantification of the frequency and consequence, and finally determination of the risks. These risk assessments provide the basis for hazards classification of facilities that govern design requirements for structures and equipment, safety analysis reports that define the accident risks that are compared to acceptance criteria, and technical safety requirements that describe the operating envelope to ensure that no undue risk is imposed on the operators or the general public.

  18. Methodology for assessing thioarsenic formation potential in sulfidic landfill environments.

    PubMed

    Zhang, Jianye; Kim, Hwidong; Townsend, Timothy

    2014-07-01

    Arsenic leaching and speciation in landfills, especially those with arsenic bearing waste and drywall disposal (such as construction and demolition (C&D) debris landfills), may be affected by high levels of sulfide through the formation of thioarsenic anions. A methodology using ion chromatography (IC) with a conductivity detector was developed for the assessment of thioarsenic formation potential in sulfidic landfill environments. Monothioarsenate (H2AsSO3(-)) and dithioarsenate (H2AsS2O2(-)) were confirmed in the IC fractions of thioarsenate synthesis mixture, consistent with previous literature results. However, the observation of AsSx(-) (x=5-8) in the supposed trithioarsenate (H2AsS3O(-)) and tetrathioarsenate (H2AsS4(-)) IC fractions suggested the presence of new arsenic polysulfide complexes. All thioarsenate anions, particularly trithioarsenate and tetrathioarsenate, were unstable upon air exposure. The method developed for thioarsenate analysis was validated and successfully used to analyze several landfill leachate samples. Thioarsenate anions were detected in the leachate of all of the C&D debris landfills tested, which accounted for approximately 8.5% of the total aqueous As in the leachate. Compared to arsenite or arsenate, thioarsenates have been reported in literature to have lower adsorption on iron oxide minerals. The presence of thioarsenates in C&D debris landfill leachate poses new concerns when evaluating the impact of arsenic mobilization in such environments.

  19. Assessment of Suited Reach Envelope in an Underwater Environment

    NASA Technical Reports Server (NTRS)

    Kim, Han; Benson, Elizabeth; Bernal, Yaritza; Jarvis, Sarah; Meginnis, Ian; Rajulu, Sudhakar

    2017-01-01

    Predicting the performance of a crewmember in an extravehicular activity (EVA) space suit presents unique challenges. The kinematic patterns of suited motions are difficult to reproduce in gravity. Additionally, 3-D suited kinematics have been practically and technically difficult to quantify in an underwater environment, in which crewmembers are commonly trained and assessed for performance. The goal of this study is to develop a hardware and software system to predictively evaluate the kinematic mobility of suited crewmembers, by measuring the 3-D reach envelope of the suit in an underwater environment. This work is ultimately aimed at developing quantitative metrics to compare the mobility of the existing Extravehicular Mobility Unit (EMU) to newly developed space suit, such as the Z-2. The EMU has been extensively used at NASA since 1981 for EVA outside the Space Shuttle and International Space Station. The Z-2 suit is NASA's newest prototype space suit. The suit is comprised of new upper torso and lower torso architectures, which were designed to improve test subject mobility.

  20. The Analysis on Space Radiation Environment and Effect of the KOMPSAT-2 Spacecraft(I): Total Ionizing Dose Effect

    NASA Astrophysics Data System (ADS)

    Baek, Myung-Jin; Kim, Hak-Jung

    2001-11-01

    In this paper, space radiation environment and total ionizing dose(TID) effect have been analyzed for the KOMPSAT-2 operational orbit. It has been revealed that the trapped protons are concentrated in the SAA(South Atlantic Anomaly) area and that the trapped protons and electrons, and solar protons are main factors affecting TID. It turned out that low energy particles can be effectively blocked by aluminum shielding thickness, but high energy particles can not be effectively blocked by increasing aluminum shielding thickness. KOMPSAT-2 total radiation dose which is accumulated continuously to spacecraft electronics has been expressed as the function of aluminum thickness. These values can be used as the criteria for the selection of electronic parts and shielding thinkness of the KOMPSAT-2 structure or electronic box.

  1. Radiation-induced biomarkers for the detection and assessment of absorbed radiation doses

    PubMed Central

    Rana, Sudha; Kumar, Raj; Sultana, Sarwat; Sharma, Rakesh Kumar

    2010-01-01

    Radiation incident involving living organisms is an uncommon but a very serious situation. The first step in medical management including triage is high-throughput assessment of the radiation dose received. Radiation exposure levels can be assessed from viability of cells, cellular organelles such as chromosome and different intermediate metabolites. Oxidative damages by ionizing radiation result in carcinogenesis, lowering of the immune response and, ultimately, damage to the hematopoietic system, gastrointestinal system and central nervous system. Biodosimetry is based on the measurement of the radiation-induced changes, which can correlate them with the absorbed dose. Radiation biomarkers such as chromosome aberration are most widely used. Serum enzymes such as serum amylase and diamine oxidase are the most promising biodosimeters. The level of gene expression and protein are also good biomarkers of radiation. PMID:21829314

  2. Implementation and Evaluation 
of a High-Dose Cytarabine Neurologic Assessment Tool.

    PubMed

    Szoch, Stephanie; Snow Kaiser, Karen

    2015-06-01

    Patients receiving high-dose cytarabine as part of their chemotherapy regimen have a chance of experiencing neurotoxicities. Prompt identification of signs and symptoms can greatly reduce the chance of patients sustaining permanent neurologic damage. This article describes the development and successful implementation of an evidence-based, standardized neurologic assessment and documentation tool that was evaluated using a clinical utility questionnaire and an adherence audit.

  3. Comparison of Risk Predicted by Multiple Norovirus Dose-Response Models and Implications for Quantitative Microbial Risk Assessment.

    PubMed

    Van Abel, Nicole; Schoen, Mary E; Kissel, John C; Meschke, J Scott

    2016-06-10

    The application of quantitative microbial risk assessments (QMRAs) to understand and mitigate risks associated with norovirus is increasingly common as there is a high frequency of outbreaks worldwide. A key component of QMRA is the dose-response analysis, which is the mathematical characterization of the association between dose and outcome. For Norovirus, multiple dose-response models are available that assume either a disaggregated or an aggregated intake dose. This work reviewed the dose-response models currently used in QMRA, and compared predicted risks from waterborne exposures (recreational and drinking) using all available dose-response models. The results found that the majority of published QMRAs of norovirus use the 1 F1 hypergeometric dose-response model with α = 0.04, β = 0.055. This dose-response model predicted relatively high risk estimates compared to other dose-response models for doses in the range of 1-1,000 genomic equivalent copies. The difference in predicted risk among dose-response models was largest for small doses, which has implications for drinking water QMRAs where the concentration of norovirus is low. Based on the review, a set of best practices was proposed to encourage the careful consideration and reporting of important assumptions in the selection and use of dose-response models in QMRA of norovirus. Finally, in the absence of one best norovirus dose-response model, multiple models should be used to provide a range of predicted outcomes for probability of infection.

  4. Phototoxic Risk Assessments on Benzophenone Derivatives: Photobiochemical Assessments and Dermal Cassette-Dosing Pharmacokinetic Study.

    PubMed

    Seto, Yoshiki; Ohtake, Hiroto; Kato, Masashi; Onoue, Satomi

    2015-08-01

    This study aimed to qualify photosafety screening on the basis of photochemical and pharmacokinetic (PK) data on dermally applied chemicals. Six benzophenone derivatives (BZPs) were selected as model compounds, and in vitro photochemical/phototoxic characterization and dermal cassette-dosing PK study were carried out. For comparison, an in vivo phototoxicity test was also conducted. All of the BZPs exhibited strong UVA/UVB absorption with molar extinction coefficients of over 2000 M(-1) × cm(-1), and benzophenone and ketoprofen exhibited significant reactive oxygen species (ROS) generation upon exposure to simulated sunlight (about 2.0 mW/cm(2)); however, ROS generation from sulisobenzone and dioxybenzone was negligible. To verify in vitro phototoxicity, a 3T3 neutral red uptake phototoxicity test was carried out, and benzophenone and ketoprofen were categorized to be phototoxic chemicals. The dermal PK parameters of ketoprofen were indicative of the highest dermal distribution of all BZPs tested. On the basis of its in vitro photochemical/phototoxic and PK data, ketoprofen was deduced to be highly phototoxic. The rank of predicted phototoxic risk of BZPs on the basis of the proposed screening strategy was almost in agreement with the results from the in vivo phototoxicity test. The combined use of photochemical and cassette-dosing PK data would provide reliable predictions of phototoxic risk for candidates with high productivity.

  5. Probabilistic dose assessment of normal operations and accident conditions for an assured isolation facility in Texas

    NASA Astrophysics Data System (ADS)

    Arno, Matthew Gordon

    Texas is investigating building a long-term waste storage facility, also known as an Assured Isolation Facility. This is an above-ground low-level radioactive waste storage facility that is actively maintained and from which waste may be retrieved. A preliminary, scoping-level analysis has been extended to consider more complex scenarios of radiation streaming and skyshine by using the computer code Monte Carlo N-Particle (MCNP) to model the facility in greater detail. Accidental release scenarios have been studied in more depth to better assess the potential dose to off-site individuals. Using bounding source term assumptions, the projected radiation doses and dose rates are estimated to exceed applicable limits by an order of magnitude. By altering the facility design to fill in the hollow cores of the prefabricated concrete slabs used in the roof over the "high-gamma rooms," where the waste with the highest concentration of gamma emitting radioactive material is stored, dose rates outside the facility decrease by an order of magnitude. With the modified design, the annual dose at the site fenceline is estimated at 86 mrem, below the 100 mrem annual limit for exposure of the public. Within the site perimeter, the dose rates are lowered sufficiently such that it is not necessary to categorize many workers and contractor personnel as radiation workers, saving on costs as well as being advisable under ALARA principles. A detailed analysis of bounding accidents incorporating information on the local meteorological conditions indicate that the maximum committed effective dose equivalent from the passage of a plume of material released in an accident at any of the cities near the facility is 59 :rem in the city of Eunice, NM based on the combined day and night meteorological conditions. Using the daytime meteorological conditions, the maximum dose at any city is 7 :rem, also in the city of Eunice. The maximum dose at the site boundary was determined to be 230 mrem

  6. Assessing pesticide exposure of the aquatic environment in tropical catchments

    NASA Astrophysics Data System (ADS)

    Weiss, Frederik; Zurbrügg, Christian; Eggen, Rik; Castillo, Luisa; Ruepert, Clemens; Stamm, Christian

    2015-04-01

    Today, pesticides are intensively used in agriculture across the globe. Worldwide about 2.4×106 tons of pesticides are used annually on 1.6×109 ha of arable land. This yields a global average use of pesticides of 1.53 kg ha-1 year-1. Available data suggest that the use in the agricultural sector will continue to grow. Recently it was estimated that within the last decade, the world pesticide market increased by 93% and the Brazilian market alone by 190%. Though pesticides are intensively used in many low and middle income countries (LAMICs), scientifically sound data of amounts and types of pesticide use and the resulting impact on water quality are lacking in many of these countries. Therefore it is highly relevant to: i) identify risk areas where pesticides affect environmental health, ii) understand the environmental behavior of pesticides in vulnerable tropical ecosystems; and iii) develop possible mitigation options to reduce their exposure to ecosystems and humans. Here we present a project that will focus on assessing pesticide exposure of the aquatic environment and humans in tropical catchments of LAMICs. A catchment in the Zarcero province in Costa Rica will be the test case. Pesticide exposure will be assessed by passive sampling. In order to cover a broad range of compounds of possible use, two sampling devices will be used: SDB membranes for collecting polar compounds and silicon sheets for accumulating apolar pesticides. Extracts will be subsequently analysed by GC-MSMS and LC-HRMS.

  7. Expanding Health Technology Assessments to Include Effects on the Environment.

    PubMed

    Marsh, Kevin; Ganz, Michael L; Hsu, John; Strandberg-Larsen, Martin; Gonzalez, Raquel Palomino; Lund, Niels

    2016-01-01

    There is growing awareness of the impact of human activity on the climate and the need to stem this impact. Public health care decision makers from Sweden and the United Kingdom have started examining environmental impacts when assessing new technologies. This article considers the case for incorporating environmental impacts into the health technology assessment (HTA) process and discusses the associated challenges. Two arguments favor incorporating environmental impacts into HTA: 1) environmental changes could directly affect people's health and 2) policy decision makers have broad mandates and objectives extending beyond health care. Two types of challenges hinder this process. First, the nascent evidence base is insufficient to support the accurate comparison of technologies' environmental impacts. Second, cost-utility analysis, which is favored by many HTA agencies, could capture some of the value of environmental impacts, especially those generating health impacts, but might not be suitable for addressing broader concerns. Both cost-benefit and multicriteria decision analyses are potential methods for evaluating health and environmental outcomes, but are less familiar to health care decision makers. Health care is an important and sizable sector of the economy that could warrant closer policy attention to its impact on the environment. Considerable work is needed to track decision makers' demands, augment the environmental evidence base, and develop robust methods for capturing and incorporating environmental data as part of HTA.

  8. Experimental investigation of radiation effect on erbium-ytterbium co-doped fiber amplifier for space optical communication in low-dose radiation environment.

    PubMed

    Ma, Jing; Li, Mi; Tan, Liying; Zhou, Yanping; Yu, Siyuan; Ran, Qiwen

    2009-08-31

    High power erbium-ytterbium co-doped fiber amplifier (EYDFA) has been radiated to the dose of 50 krad at the dose rate of 40 rad/s. Some key parameters have been measured to investigate the radiation effect on the EYDFA for space optical communication. Considering the dose of 50 krad is big enough to the most of low-dose radiation environment, these experimental results will be a good reference for the low-dose inter-satellite optical communication designers.

  9. A Novel Approach to Pharmacodynamic Assessment of Antimicrobial Agents: New Insights to Dosing Regimen Design

    PubMed Central

    Tam, Vincent H.; Nikolaou, Michael

    2011-01-01

    Pharmacodynamic modeling has been increasingly used as a decision support tool to guide dosing regimen selection, both in the drug development and clinical settings. Killing by antimicrobial agents has been traditionally classified categorically as concentration-dependent (which would favor less fractionating regimens) or time-dependent (for which more frequent dosing is preferred). While intuitive and useful to explain empiric data, a more informative approach is necessary to provide a robust assessment of pharmacodynamic profiles in situations other than the extremes of the spectrum (e.g., agents which exhibit partial concentration-dependent killing). A quantitative approach to describe the interaction of an antimicrobial agent and a pathogen is proposed to fill this unmet need. A hypothetic antimicrobial agent with linear pharmacokinetics is used for illustrative purposes. A non-linear functional form (sigmoid Emax) of killing consisted of 3 parameters is used. Using different parameter values in conjunction with the relative growth rate of the pathogen and antimicrobial agent concentration ranges, various conventional pharmacodynamic surrogate indices (e.g., AUC/MIC, Cmax/MIC, %T>MIC) could be satisfactorily linked to outcomes. In addition, the dosing intensity represented by the average kill rate of a dosing regimen can be derived, which could be used for quantitative comparison. The relevance of our approach is further supported by experimental data from our previous investigations using a variety of gram-negative bacteria and antimicrobial agents (moxifloxacin, levofloxacin, gentamicin, amikacin and meropenem). The pharmacodynamic profiles of a wide range of antimicrobial agents can be assessed by a more flexible computational tool to support dosing selection. PMID:21253559

  10. Probabilistic assessment of the influence of lake properties in long-term radiation doses to humans.

    PubMed

    Pohjola, Jari; Turunen, Jari; Lipping, Tarmo; Ikonen, Ari T K

    2016-11-01

    The assessment processes concerning the safety of nuclear waste repositories include the modelling of radionuclide transport in biosphere and the evaluation of the doses to the most affected humans. In this paper, a scenario, in which a contaminated lake is the water source for drinking water, irrigation water and watering of livestock, is presented. The objective of the paper is to probabilistically study the influence of lake properties as parameters in the assessment scenario. The properties of the lake are a result of previously conducted probabilistic studies, where the land uplift of the terrain surrounding the repositories and the formation of water bodies were studied in a 10,000-year time span using Monte Carlo simulation. The lake is formed at 3000 years from present day and the changing properties of the lake have been used in the study. The studied radionuclides (36)Cl, (135)Cs, (129)I, (237)Np, (90)Sr, (99)Tc and (238)U enter the lake with a rate of 1 Bq/year. The transport process from the lake water to humans is described and the doses (dose conversion factors) to adult humans are evaluated based on a study on average food consumption. Sensitivity analysis is used for identifying the parameters having the most influence on the outcome of the dose. Based on the results from the sensitivity analysis, the volumetric outflow rate of the lake and the volume of the lake were taken into closer consideration. The results show the influence of probabilistically derived geomorphic lake input parameters on the dose.

  11. The effective dose assessment of C-arm CT in hepatic arterial embolisation therapy.

    PubMed

    Tyan, Y-S; Li, Y-Y; Ku, M-C; Huang, H-H; Chen, T-R

    2013-04-01

    To assess the effective dose of the liver C-arm computed tomography (CT) scan during hepatic arterial embolisation surgery with clinical dose-area product (DAP) data from Taiwan. The experiment used two kinds of phantoms: RANDO® Man and RANDO Woman (The Phantom Laboratory, Salem, NY), embedded with thermoluminescent dosemeters at locations according to the International Commission on Radiological Protection 103 report. The conversion factors of DAP to effective doses for males and females, respectively, were obtained. The clinical DAP data of liver C-arm CT scan during hepatic arterial embolisation surgery were collected in a hospital in Taiwan. There were 125 liver transarterial embolisation therapy cases, including 94 males and 31 females, from February 2009 to June 2010. C-arm CT was used 38 times for males and 17 times for females. The corresponding average and standard deviation of clinical DAP were 61.0±6.6 Gy cm(2) and 52.2±8.3 Gy cm(2), respectively. The DAP of RANDO Man and RANDO Woman phantoms simply scanned by C-arm CT are much lower than that of patients. After consideration of the clinical DAP of patients, the effective doses of a liver C-arm CT scan recommended for males and females in Taiwan are 11.5±2.3 mSv and 11.3±3.0 mSv, respectively. The conversion factors of DAP to effective doses for males and females are 0.19±0.03 mSv Gy(-1) cm(-2) and 0.22±0.05 mSv Gy(-1) cm(-2). Only if the actual DAP value of a patient scan is multiplied by the conversion factor can the correct effective dose be determined.

  12. Technology Assessment and Roadmap for the Emergency Radiation Dose Assessment Program (ERDAP)

    DTIC Science & Technology

    2005-06-01

    research, development, test , and evaluation services between the U.S. Department of Energy and the Regents of the University of California as operator of...assessment technologies. Conduct a demonstration program to assess the value of existing and proposed technologies • Conduct field tests and leverage...cost, size/weight, and ruggedness) in realistic test scenarios. • Luminescence, particularly Optically Stimulated Luminescence (OSL) and Electron

  13. Personnel neutron dose assessment upgrade: Volume 2, Field neutron spectrometer for health physics applications

    SciTech Connect

    Brackenbush, L.W.; Reece, W.D.; Miller, S.D.; Endres, G.W.R.; Durham, J.S.; Scherpelz, R.I.; Tomeraasen, P.L.; Stroud, C.M.; Faust, L.G.; Vallario, E.J.

    1988-07-01

    Both the (ICRP) and the (NCPR) have recommended an increase in neutron quality factors and the adoption of effective dose equivalent methods. The series of reports entitled Personnel Neutron Dose Assessment Upgrade (PNL-6620) addresses these changes. Volume 1 in this series of reports (Personnel Neutron Dosimetry Assessment) provided guidance on the characteristics, use, and calibration of personnel neutron dosimeters in order to meet the new recommendations. This report, Volume 2: Field Neutron Spectrometer for Health Physics Applications describes the development of a portable field spectrometer which can be set up for use in a few minutes by a single person. The field spectrometer described herein represents a significant advance in improving the accuracy of neutron dose assessment. It permits an immediate analysis of the energy spectral distribution associated with the radiation from which neutron quality factor can be determined. It is now possible to depart from the use of maximum Q by determining and realistically applying a lower Q based on spectral data. The field spectrometer is made up of two modules: a detector module with built-in electronics and an analysis module with a IBM PC/reg sign/-compatible computer to control the data acquisition and analysis of data in the field. The unit is simple enough to allow the operator to perform spectral measurements with minimal training. The instrument is intended for use in steady-state radiation fields with neutrons energies covering the fission spectrum range. The prototype field spectrometer has been field tested in plutonium processing facilities, and has been proven to operate satisfactorily. The prototype field spectrometer uses a /sup 3/He proportional counter to measure the neutron energy spectrum between 50 keV and 5 MeV and a tissue equivalent proportional counter (TEPC) to measure absorbed neutron dose.

  14. SU-F-I-38: Patient Organ Specific Dose Assessment in Coronary CT Angiograph Using Voxellaized Volume Dose Index in Monte Carlo Simulation

    SciTech Connect

    Fallal, Mohammadi Gh.; Riyahi, Alam N.; Graily, Gh.; Paydar, R.

    2016-06-15

    Purpose: Clinical use of multi detector computed tomography(MDCT) in diagnosis of diseases due to high speed in data acquisition and high spatial resolution is significantly increased. Regarding to the high radiation dose in CT and necessity of patient specific radiation risk assessment, the adoption of new method in the calculation of organ dose is completely required and necessary. In this study by introducing a conversion factor, patient organ dose in thorax region based on CT image data using MC system was calculated. Methods: The geometry of x-ray tube, inherent filter, bow tie filter and collimator were designed using EGSnrc/BEAMnrc MC-system component modules according to GE-Light-speed 64-slices CT-scanner geometry. CT-scan image of patient thorax as a specific phantom was voxellised with 6.25mm3 in voxel and 64×64×20 matrix size. Dose to thorax organ include esophagus, lung, heart, breast, ribs, muscle, spine, spinal cord with imaging technical condition of prospectively-gated-coronary CT-Angiography(PGT) as a step and shoot method, were calculated. Irradiation of patient specific phantom was performed using a dedicated MC-code as DOSXYZnrc with PGT-irradiation model. The ratio of organ dose value calculated in MC-method to the volume CT dose index(CTDIvol) reported by CT-scanner machine according to PGT radiation technique has been introduced as conversion factor. Results: In PGT method, CTDIvol was 10.6mGy and Organ Dose/CTDIvol conversion factor for esophagus, lung, heart, breast, ribs, muscle, spine and spinal cord were obtained as; 0.96, 1.46, 1.2, 3.28. 6.68. 1.35, 3.41 and 0.93 respectively. Conclusion: The results showed while, underestimation of patient dose was found in dose calculation based on CTDIvol, also dose to breast is higher than the other studies. Therefore, the method in this study can be used to provide the actual patient organ dose in CT imaging based on CTDIvol in order to calculation of real effective dose(ED) based on organ dose

  15. Assessment of the exposure to and dose from radon decay products in normally occupied homes

    SciTech Connect

    Hopke, P.K.; Jensen, B.; Li, C.S.; Montassier, N.; Wasiolek, P.; Cavallo, A.J.; Gatsby, K.; Socolow, R.H.; James, A.C.

    1995-05-01

    The exposure to radon decay products has been assessed in seven homes in the northeastern United States and southeastern Canada. In two of the houses, there was a single individual who smoked cigarettes. There were a variety of heating and cooking appliances among these homes. These studies have provide 565 measurements of the activity-weighted size distributions in these houses. The median value for the equilibrium factor was 0.408 as compared with the previously employed value of 0.50. Using the recently adopted ICRP lung deposition and dosimetry model, the hourly equivalent lung dose rate per unit, radon exposure was estimated for each measured size distribution. Differences between houses with smokers present and absent were noted in the exposure conditions, but the resulting dose rate per unit of radon gas concentration was essentially the same for the two groups. Expressed in terms of ICRP`s unit of effective dose for members of the public, the mean dose rate conversion coefficient with respect to radon gas concentration found in this study was 3.8 nSv h{sup -} Bq{sup -} m{sup -3}. 26 refs., 8 figs., 3 tabs.

  16. Screening level dose assessment of aquatic biota downstream of the Marcoule nuclear complex in southern France

    SciTech Connect

    St-Pierre, S.; Chambers, D.B.; Lowe, L.M.; Bontoux, J.G.

    1999-09-01

    Aquatic biota in the Rhone River downstream of the Marcoule nuclear complex in France are exposed to natural sources of radiation and to radioactivity released from the Marcoule complex. A simple conservative screening level model was used to estimate the range of concentrations in aquatic media of both artificial and natural radionuclides and the consequent absorbed dose rates for aquatic organisms. Five categories of aquatic organisms were studied, namely, submerged aquatic plants (phanerogam), non-bottom-feeding fish, bottom-feeding fish, mollusca, and fish-eating birds. The analysis was based on the radionuclide concentrations reported in four consecutive annual radioecological monitoring reports published by French agencies with nuclear regulatory responsibilities. The results of this assessment were used to determine, qualitatively, the magnitude of any potential health impacts on each of the five categories of aquatic organisms studied. The range of dose rate estimates ranged over three orders of magnitude, with maximum dose rates estimated to be in the order of 1 to 10 {micro}Gy h{sup {minus}1}. These maximum dose rates are a factor 40 or more below the international guideline intended to ensure the protection of aquatic populations, and a factor ten or more below the level which may trigger the need for a more detailed evaluation of potential ecological consequences to the exposed populations.

  17. Rapid assessment of radiobiological doses for terrestrial and interplanetary space missions.

    PubMed

    Melkonian, G; Bourrieau, J

    1994-11-01

    This paper presents the doses levels expected in orbits in chart form, covering the range 300-800 km of altitude and 0-90 degrees of inclination behind shieldings similar to the Hermes spacecraft and the EVA spacesuit matter distributions. These charts allow users to rapidly find the radiobiological dose received in the most critical organs of the human body either in normal situations or during a large solar event. Outside the magnetosphere, during interplanetary or lunar missions, when the dose received during crossing of the radiation belts become negligible, the dose is due to galactic cosmic rays (GCR) and solar flares. The correct radiobiological assessment of the components of this radiation field becomes a major problem. On the Moon a permanent ground-based station can be shielded by lunar materials against meteoroids and radiations. The radiobiological hazard, essentially linked to the solar flare risk during the transfer phase and the extra-station activities, may be solved by mission planning. For interplanetary flights the problem comes from both increased risk of solar events and from the continuous exposure to GCR. These energetic particles cannot be easily stopped by shieldings; cost considerations imply that more effective materials must be used. Impact on the vehicle design and the mission planning is important.

  18. Radiological dose assessment of NORM disposal in Class II injection wells

    SciTech Connect

    Smith, K.P.; Williams, G.P.; Blunt, D.L.; Arnish, J.J.

    1997-09-01

    Subsurface disposal of petroleum industry wastes containing naturally occurring radioactive material (NORM) via injection into Class II wells was modeled to estimate potential radiological doses to individuals consuming water from a shallow aquifer. A generic model was developed for the injection of 100,000 barrels of NORM waste containing 2,000 picocuries per liter of radium into a layered geologic system. In separate modeling runs, it was assumed that a casing failure released the entire volume of NORM into each successive geologic layer, including the shallow aquifer. Radionuclide concentrations and related potential doses were calculated for receptors located in the shallow aquifer from 0 to 20 miles down gradient of the injection well. The results indicated that even under conservative assumptions, calculated radionuclide concentrations and potential doses associated with subsurface disposal of NORM in Class II wells were below levels of regulatory concern. The preliminary results from a dose assessment of a specific project entailing injection of NORM into Class II wells support the conclusions of the generic study.

  19. Effects assessment: boron compounds in the aquatic environment.

    PubMed

    Schoderboeck, Lucia; Mühlegger, Simone; Losert, Annemarie; Gausterer, Christian; Hornek, Romana

    2011-01-01

    In previous studies, boron compounds were considered to be of comparatively low toxicity in the aquatic environment, with predicted no effect concentration (PNEC) values ranging around 1 mg B/L (expressed as boron equivalent). In the present study, we describe an evaluation of toxicity data for boron available for the aquatic environment by different methods. For substances with rich datasets, it is often possible to perform a species sensitivity distribution (SSD). The typical outcome of an SSD is the Hazardous Concentration 5% (HC5), the concentration at which 95% of all species are protected with a probability of 95%. The data set currently available on the toxic effects of boron compounds to aquatic organisms is comprehensive, but a careful evaluation of these data revealed that chronic data for aquatic insects and plants are missing. In the present study both the standard assessment factor approach as well as the SSD approach were applied. The standard approach led to a PNEC of 0.18 mg B/L (equivalent to 1.03 mg boric acid/L), while the SSD approach resulted in a PNEC of 0.34 mg B/L (equivalent to 1.94 mg boric acid/L). These evaluations indicate that boron compounds could be hazardous to aquatic organisms at concentrations close to the natural environmental background in some European regions. This suggests a possible high sensitivity of some ecosystems for anthropogenic input of boron compounds. Another concern is that the anthropogenic input of boron could lead to toxic effects in organisms adapted to low boron concentration.

  20. Dosimetry concepts for scanner quality assurance and tissue dose assessment in micro-CT

    SciTech Connect

    Hupfer, Martin; Kolditz, Daniel; Nowak, Tristan; Eisa, Fabian; Brauweiler, Robert; Kalender, Willi A.

    2012-02-15

    Purpose: At present, no established methods exist for dosimetry in micro computed tomography (micro-CT). The purpose of this study was therefore to investigate practical concepts for both dosimetric scanner quality assurance and tissue dose assessment for micro-CT. Methods: The computed tomography dose index (CTDI) was adapted to micro-CT and measurements of the CTDI both free in air and in the center of cylindrical polymethyl methacrylate (PMMA) phantoms of 20 and 32 mm diameter were performed in a 6 month interval with a 100 mm pencil ionization chamber calibrated for low tube voltages. For tissue dose assessment, z-profile measurements using thermoluminescence dosimeters (TLDs) were performed and both profile and CTDI measurements were compared to Monte Carlo (MC) dose calculations to validate an existing MC tool for use in micro-CT. The consistency of MC calculations and TLD measurements was further investigated in two mice cadavers. Results: CTDI was found to be a reproducible quantity for constancy tests on the micro-CT system under study, showing a linear dependence on tube voltage and being by definition proportional to mAs setting and z-collimation. The CTDI measured free in air showed larger systematic deviations after the 6 month interval compared to the CTDI measured in PMMA phantoms. MC calculations were found to match CTDI measurements within 3% when using x-ray spectra measured at our micro-CT installation and better than 10% when using x-ray spectra calculated from semi-empirical models. Visual inspection revealed good agreement for all z-profiles. The consistency of MC calculations and TLD measurements in mice was found to be better than 10% with a mean deviation of 4.5%. Conclusions: Our results show the CTDI implemented for micro-CT to be a promising candidate for dosimetric quality assurance measurements as it linearly reflects changes in tube voltage, mAs setting, and collimation used during the scan, encouraging further studies on a variety of

  1. Methods for assessing background levels of radiation and radioactive materials in the environment around uranium mills

    SciTech Connect

    Wogman, N.A.; Silker, W.B.; Glissmeyer, J.A.; Endres, G.W.R.

    1980-04-01

    Techniques and costs for determining background levels and mill contributions to the environment are assessed. Three specific programs are identified for the determination of natural background and mill contributions to that background. Since the most significant radiological impact to man within 10 km of mill tailings occurs through airborne /sup 222/Rn and its daughters, their measurement is emphasized in the suggested procedures. The next major radiological impact from the mills occurs through airborne movement of particulates from the mill and its tailings piles. Thus, the more sophisticated measurement technologies presented include measurements of airborne radionuclide particulates, as well as methods to measure the dose from /sup 222/Rn and its daughters. The most expensive methods for assessing background levels of radioactive materials around uranium mills allow a determination of uranium, thorium, and radium in water, soil, and vegetation, as well as air. The methodologies are organized by their increasing capital and operating costs. The more expensive techniques provide a better evaluation of the mill contribution to the environment. There is no single universal technique that is applicable to all mills.

  2. Assessing the exposure risk and impacts of pharmaceuticals in the environment on individuals and ecosystems.

    PubMed

    Arnold, Kathryn E; Boxall, Alistair B A; Brown, A Ross; Cuthbert, Richard J; Gaw, Sally; Hutchinson, Thomas H; Jobling, Susan; Madden, Judith C; Metcalfe, Chris D; Naidoo, Vinny; Shore, Richard F; Smits, Judit E; Taggart, Mark A; Thompson, Helen M

    2013-08-23

    The use of human and veterinary pharmaceuticals is increasing. Over the past decade, there has been a proliferation of research into potential environmental impacts of pharmaceuticals in the environment. A Royal Society-supported seminar brought together experts from diverse scientific fields to discuss the risks posed by pharmaceuticals to wildlife. Recent analytical advances have revealed that pharmaceuticals are entering habitats via water, sewage, manure and animal carcases, and dispersing through food chains. Pharmaceuticals are designed to alter physiology at low doses and so can be particularly potent contaminants. The near extinction of Asian vultures following exposure to diclofenac is the key example where exposure to a pharmaceutical caused a population-level impact on non-target wildlife. However, more subtle changes to behaviour and physiology are rarely studied and poorly understood. Grand challenges for the future include developing more realistic exposure assessments for wildlife, assessing the impacts of mixtures of pharmaceuticals in combination with other environmental stressors and estimating the risks from pharmaceutical manufacturing and usage in developing countries. We concluded that an integration of diverse approaches is required to predict 'unexpected' risks; specifically, ecologically relevant, often long-term and non-lethal, consequences of pharmaceuticals in the environment for wildlife and ecosystems.

  3. Assessing the exposure risk and impacts of pharmaceuticals in the environment on individuals and ecosystems

    PubMed Central

    Arnold, Kathryn E.; Boxall, Alistair B. A.; Brown, A. Ross; Cuthbert, Richard J.; Gaw, Sally; Hutchinson, Thomas H.; Jobling, Susan; Madden, Judith C.; Metcalfe, Chris D.; Naidoo, Vinny; Shore, Richard F.; Smits, Judit E.; Taggart, Mark A.; Thompson, Helen M.

    2013-01-01

    The use of human and veterinary pharmaceuticals is increasing. Over the past decade, there has been a proliferation of research into potential environmental impacts of pharmaceuticals in the environment. A Royal Society-supported seminar brought together experts from diverse scientific fields to discuss the risks posed by pharmaceuticals to wildlife. Recent analytical advances have revealed that pharmaceuticals are entering habitats via water, sewage, manure and animal carcases, and dispersing through food chains. Pharmaceuticals are designed to alter physiology at low doses and so can be particularly potent contaminants. The near extinction of Asian vultures following exposure to diclofenac is the key example where exposure to a pharmaceutical caused a population-level impact on non-target wildlife. However, more subtle changes to behaviour and physiology are rarely studied and poorly understood. Grand challenges for the future include developing more realistic exposure assessments for wildlife, assessing the impacts of mixtures of pharmaceuticals in combination with other environmental stressors and estimating the risks from pharmaceutical manufacturing and usage in developing countries. We concluded that an integration of diverse approaches is required to predict ‘unexpected’ risks; specifically, ecologically relevant, often long-term and non-lethal, consequences of pharmaceuticals in the environment for wildlife and ecosystems. PMID:23804293

  4. An assessment of wheat breeding gains in hot environments

    NASA Astrophysics Data System (ADS)

    Gourdji, S. M.; Mathews, K.; Reynolds, M.; Crossa, J.; Lobell, D. B.

    2012-12-01

    Wheat, a critical crop for ensuring global food security, has the lowest optimum temperatures among the major cereals, and is already grown in many heat stress areas, thereby increasing risks to production from a warming climate. Historical spring wheat trial data from the International Maize and Wheat Improvement Center (CIMMYT) was used to investigate the relationship between environmental conditions and yield in major wheat-growing areas, assess the response to future warming, and identify different rates of genetic gains due to variety improvement across environments and breeding nurseries. Results were compared for two nurseries: 1) the Elite Spring Wheat Yield Trial (ESWYT), which aims to improve yield potential under optimal environmental conditions, and 2) the Semi-Arid Wheat Yield Trial (SAWYT), where improvements are targeted in semi-arid, rainfed environments, frequently subject to heat and water stress. Yields from 25 years of trial data were paired with reconstructed daily weather data in an empirical model with environmental variables averaged by growth stage. Temperature, radiation, day length and interaction terms between temperature and vapor pressure deficit (VPD) were all determined to be significant terms in the model. Results show a detrimental response to warming across all temperatures in the grain-filling, or final growth stage, particularly under low VPD/ humid conditions. A negative response to warming was also observed in the reproductive stage after ~14C, although high VPD conferred no additional benefit, perhaps due to a higher sensitivity and/or exposure to water stress during this period. A projected 2C season average warming was seen to have differential effects between ESWYT and SAWYT, with SAWYT germplasm less sensitive to warming up until ~21C, but an equally negative response to further warming for both nurseries. The regions where wheat is already grown under hot, and sometimes humid, conditions, particularly in south and south

  5. GATE Monte Carlo simulation of dose distribution using MapReduce in a cloud computing environment.

    PubMed

    Liu, Yangchuan; Tang, Yuguo; Gao, Xin

    2017-08-31

    The GATE Monte Carlo simulation platform has good application prospects of treatment planning and quality assurance. However, accurate dose calculation using GATE is time consuming. The purpose of this study is to implement a novel cloud computing method for accurate GATE Monte Carlo simulation of dose distribution using MapReduce. An Amazon Machine Image installed with Hadoop and GATE is created to set up Hadoop clusters on Amazon Elastic Compute Cloud (EC2). Macros, the input files for GATE, are split into a number of self-contained sub-macros. Through Hadoop Streaming, the sub-macros are executed by GATE in Map tasks and the sub-results are aggregated into final outputs in Reduce tasks. As an evaluation, GATE simulations were performed in a cubical water phantom for X-ray photons of 6 and 18 MeV. The parallel simulation on the cloud computing platform is as accurate as the single-threaded simulation on a local server and the simulation correctness is not affected by the failure of some worker nodes. The cloud-based simulation time is approximately inversely proportional to the number of worker nodes. For the simulation of 10 million photons on a cluster with 64 worker nodes, time decreases of 41× and 32× were achieved compared to the single worker node case and the single-threaded case, respectively. The test of Hadoop's fault tolerance showed that the simulation correctness was not affected by the failure of some worker nodes. The results verify that the proposed method provides a feasible cloud computing solution for GATE.

  6. Dose-to-dose variations with single packages of counterfeit medicines and adulterated dietary supplements as a potential source of false negatives and inaccurate health risk assessments.

    PubMed

    Venhuis, B J; Zwaagstra, M E; Keizers, P H J; de Kaste, D

    2014-02-01

    In this report, we show three examples of how the variability in dose units in single packages of counterfeit medicines and adulterated dietary supplements may contribute to a false negative screening result and inaccurate health risk assessments. We describe a counterfeit Viagra 100mg blister pack and a box of an instant coffee both containing dose units with and without an active pharmaceutical ingredient (API). We also describe a purportedly herbal slimming product with capsules that mutually differed in API and impurities. The adulterated dietary supplements contained sibutramine, benzyl-sibutramine, N-desmethyl-sibutramine (DMS), N,N-didesmethyl-sibutramine (DDMS) and several other related impurities. Counterfeit medicines and adulterated dietary supplements are a health risk because their quality is unreliable. Health risks are even greater when such unreliability extends to fundamental differences between dose units in one package. Because dose-to-dose variability for these products is unpredictable, the confidence interval of a sample size is unknown. Consequently, the analyses of a selection of dose units may not be representative for the package. In the worst case, counterfeit or unauthorised medicines are not recognised as such or a health risk is not identified. In order to reduce erroneous results particular care should be taken when analysing a composite of dose units, when finding no API in a dietary supplement and when finding conformity in a suspect counterfeit medicine. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. General guidelines for the assessment of internal dose from monitoring data: progress of the IDEAS project.

    PubMed

    Doerfel, H; Andrasi, A; Bailey, M; Blanchardon, E; Cruz-Suarez, R; Berkovski, V; Castellani, C-M; Hurtgen, C; LeGuen, B; Malatova, I; Marsh, J; Stather, J; Zeger, J

    2007-01-01

    In recent major international intercomparison exercises on intake and internal dose assessments from monitoring data, the results calculated by different participants varied significantly. Based on this experience the need for harmonisation of the procedures has been formulated within an EU 5th Framework Programme research project. The aim of the project, IDEAS, is to develop general guidelines for standardising assessments of intakes and internal doses. The IDEAS project started in October 2001 and ended in June 2005. The project is closely related to some goals of the work of Committee 2 of the ICRP and since 2003 there has been close cooperation between the two groups. To ensure that the guidelines are applicable to a wide range of practical situations, the first step was to compile a database of well-documented cases of internal contamination. In parallel, an improved version of an existing software package was developed and distributed to the partners for further use. A large number of cases from the database was evaluated independently by the partners and the results reviewed. Based on these evaluations, guidelines were drafted and discussed with dosimetry professionals from around the world by means of a virtual workshop on the Internet early in 2004. The guidelines have been revised and refined on the basis of the experiences and discussions in this virtual workshop. The general philosophy of the Guidelines is presented here, focusing on the principles of harmonisation, optimisation and proportionality. Finally, the proposed Levels of Task to structure the approach of internal dose evaluation are reported.

  8. Evolving Adjustments to External (Gamma) Slope Factors for CERCLA Risk and Dose Assessments - 12290

    SciTech Connect

    Walker, Stuart

    2012-07-01

    To model the external exposure pathway in risk and dose assessments of radioactive contamination at Superfund sites, the U.S. Environmental Protection Agency (EPA) uses slope factors (SFs), also known as risk coefficients, and dose conversion factors (DCFs). Without any adjustment these external radiation exposure pathways effectively assumes that an individual is exposed to a source geometry that is effectively an infinite slab. The concept of an 'infinite slab' means that the thickness of the contaminated zone and its aerial extent are so large that it behaves as if it were infinite in its physical dimensions. EPA has been making increasingly complex adjustments to account for the extent of the contamination and its corresponding radiation field to provide more accurate risk and dose assessment modeling when using its calculators. In most instances, the more accurate modeling results derived from these gamma adjustments are less conservative. The notable exception are for some radionuclides in rooms with contaminated walls, ceiling, and floors, and the receptor is in location of the room with the highest amount of radiation exposure, usually the corner of small rooms and the center of large conference rooms. (authors)

  9. Aldrin and dieldrin: a reevaluation of the cancer and noncancer dose-response assessments.

    PubMed

    Hooker, Eric P; Fulcher, Keri G; Gibb, Herman J

    2014-05-01

    The dose-response analyses of cancer and noncancer health effects of aldrin and dieldrin were evaluated using current methodology, including benchmark dose analysis and the current U.S. Environmental Protection Agency (U.S. EPA) guidance on body weight scaling and uncertainty factors. A literature review was performed to determine the most appropriate adverse effect endpoints. Using current methodology and information, the estimated reference dose values were 0.0001 and 0.00008 mg/kg-day for aldrin and dieldrin, respectively. The estimated cancer slope factors for aldrin and dieldrin were 3.4 and 7.0 (mg/kg-day)(-1), respectively (i.e., about 5- and 2.3-fold lower risk than the 1987 U.S. EPA assessments). Because aldrin and dieldrin are no longer used as pesticides in the United States, they are presumed to be a low priority for additional review by the U.S. EPA. However, because they are persistent and still detected in environmental samples, quantitative risk assessments based on the best available methods are required. Recent epidemiologic studies do not demonstrate a causal association between aldrin and dieldrin and human cancer risk. The proposed reevaluations suggest that these two compounds pose a lower human health risk than currently reported by the U.S. EPA. © 2013 Society for Risk Analysis.

  10. Rapid radiation dose assessment for radiological public health emergencies: roles of NIAID and BARDA.

    PubMed

    Grace, Marcy B; Moyer, Brian R; Prasher, Joanna; Cliffer, Kenneth D; Ramakrishnan, Narayani; Kaminski, Joseph; Coleman, C Norman; Manning, Ronald G; Maidment, Bert W; Hatchett, Richard

    2010-02-01

    A large-scale radiological incident would result in an immediate critical need to assess the radiation doses received by thousands of individuals to allow for prompt triage and appropriate medical treatment. Measuring absorbed doses of ionizing radiation will require a system architecture or a system of platforms that contains diverse, integrated diagnostic and dosimetric tools that are accurate and precise. For large-scale incidents, rapidity and ease of screening are essential. The National Institute of Allergy and Infectious Diseases of the National Institutes of Health is the focal point within the Department of Health and Human Services (HHS) for basic research and development of medical countermeasures for radiation injuries. The Biomedical Advanced Research and Development Authority within the HHS Office of the Assistant Secretary for Preparedness and Response coordinates and administers programs for the advanced development and acquisition of emergency medical countermeasures for the Strategic National Stockpile. Using a combination of funding mechanisms, including funds authorized by the Project BioShield Act of 2004 and those authorized by the Pandemic and All-Hazards Preparedness Act of 2006, HHS is enhancing the nation's preparedness by supporting the radiation dose assessment capabilities that will ensure effective and appropriate use of medical countermeasures in the aftermath of a radiological or nuclear incident.

  11. Results of comparative assessment of US and Foreign Nuclear Power Plant dose experience and dose reduction programs

    SciTech Connect

    Baum, J.W.; Horan, J.R.; Dionne, B.J.

    1984-01-01

    Based on data evaluated to date it is clear that US plants have higher collective dose equivalents per reactor and per MW-y generated than most other countries. Factors which contribute to low doses include: (1) minimization of cobalt in primary system components exposed to water, (2) careful control of primary system oxygen and pH, (3) good primary system water purity to minimize corrosion product formation, (4) careful plant design, layout and component segration and shielding, (5) management interest and commitment, (6) minimum number of workers and in-depth worker training, (7) use of special tools, and (8) plant standardization. It should be pointed out that reductions in exposure are more difficult and costly in plants already built and operating. The cost-effectiveness of dose reduction efforts at US plants should be carefully evaluated before recommendations are made concerning existing plants.

  12. The Counseling Training Environment Scale (CTES): Development of a Self-Report Measure to Assess Counseling Training Environment

    ERIC Educational Resources Information Center

    Lau, Jared Miki Jun Kong

    2012-01-01

    Based on Bronfenbrenner's (1979, 1992) ecological framework, the Counseling Training Environment Scale (CTES) was developed as a self-report measure that assesses the learning and training environment of counseling and related mental health training programs as perceived by current students. A two-phase mixed-methods design was used to create…

  13. Model for assessing radiation dose to epithelial cells of the human respiratory tract from radon progeny

    SciTech Connect

    Fisher, D.R.; Hui, T.E.; James, A.C.

    1990-07-01

    A computational model was developed to evaluate radiation doses to sensitive cells from exposure to radon progeny throughout human bronchial epithelium. The model incorporated current information on nasal and oral filtration efficiencies for unattached radon progeny, characteristics of bronchial deposition by diffusive and inertial processes, mucous clearance and possible transfer of radon progeny to the airway epithelium, locations of target nuclei of secretory and basal cells in different regions of the bronchial tree epithelium, and other features. The model is useful for evaluating absorbed doses to various populations of target cell nuclei, the associated microdosimetric probability densities in specific energy, and the likelihood that target nuclei are hit one or more times by alpha-particle tracks. The model was applied to extrapolating lung cancer risks observed in underground miners to the general population exposed to low-level radon progeny in indoor home environments. The effect of increasing exposure rates by one and two orders of magnitude in both environments was modeled to determine the frequency of radiation events in target cell nuclei. The implications of dosimetric modeling for lung cancer risk analysis were also examined. 28 refs., 5 figs., 5 tabs.

  14. In vivo assessment of the gastric mucosal tolerance dose after single fraction, small volume irradiation of liver malignancies by computed tomography-guided, high-dose-rate brachytherapy

    SciTech Connect

    Streitparth, Florian; Pech, Maciej; Boehmig, Michael; Ruehl, Ricarda; Peters, Nils; Wieners, Gero; Steinberg, Johannes; Lopez-Haenninen, Enrique; Felix, Roland; Wust, Peter; Ricke, Jens . E-mail: jens.ricke@medizin.uni-magdeburg.de

    2006-08-01

    Purpose: The aim of this study was to assess the tolerance dose of gastric mucosa for single-fraction computed tomography (CT)-guided, high-dose-rate (HDR) brachytherapy of liver malignancies. Methods and Materials: A total of 33 patients treated by CT-guided HDR brachytherapy of liver malignancies in segments II and/or III were included. Dose planning was performed upon a three-dimensional CT data set acquired after percutaneous applicator positioning. All patients received gastric protection post-treatment. For further analysis, the contours of the gastric wall were defined in every CT slice using Brachyvision Software. Dose-volume histograms were calculated for each treatment and correlated with clinical data derived from questionnaires assessing Common Toxicity Criteria (CTC). All patients presenting symptoms of upper GI toxicity were examined endoscopically. Results: Summarizing all patients the minimum dose applied to 1 ml of the gastric wall (D{sub 1ml}) ranged from 6.3 to 34.2 Gy; median, 14.3 Gy. Toxicity was present in 18 patients (55%). We found nausea in 16 (69%), emesis in 9 (27%), cramping in 13 (39%), weight loss in 12 (36%), gastritis in 4 (12%), and ulceration in 5 patients (15%). We found a threshold dose D{sub 1ml} of 11 Gy for general gastric toxicity and 15.5 Gy for gastric ulceration verified by an univariate analysis (p = 0.01). Conclusions: For a single fraction, small volume irradiation we found in the upper abdomen a threshold dose D{sub 1ml} of 15.5 Gy for the clinical endpoint ulceration of the gastric mucosa. This in vivo assessment is in accordance with previously published tolerance data.

  15. Personnel neutron dose assessment upgrade: Volume 1, Personnel neutron dosimetry assessment: (Final report)

    SciTech Connect

    Hadlock, D.E.; Brackenbush, L.W.; Griffith, R.V.; Hankins, D.E.; Parkhurst, M.A.; Stroud, C.M.; Faust, L.G.; Vallario, E.J.

    1988-07-01

    This report provides guidance on the characteristics, use, and calibration criteria for personnel neutron dosimeters. The report is applicable for neutrons with energies ranging from thermal to less than 20 MeV. Background for general neutron dosimetry requirements is provided, as is relevant federal regulations and other standards. The characteristics of personnel neutron dosimeters are discussed, with particular attention paid to passive neutron dosimetry systems. Two of the systems discussed are used at DOE and DOE-contractor facilities (nuclear track emulsion and thermoluminescent-albedo) and another (the combination TLD/TED) was recently developed. Topics discussed in the field applications of these dosimeters include their theory of operation, their processing, readout, and interpretation, and their advantages and disadvantages for field use. The procedures required for occupational neutron dosimetry are discussed, including radiation monitoring and the wearing of dosimeters, their exchange periods, dose equivalent evaluations, and the documenting of neutron exposures. The coverage of dosimeter testing, maintenance, and calibration includes guidance on the selection of calibration sources, the effects of irradiation geometries, lower limits of detectability, fading, frequency of calibration, spectrometry, and quality control. 49 refs., 6 figs., 8 tabs.

  16. Assessment of natural radioactivity concentrations and gamma dose levels around Shorapur, Karnataka

    SciTech Connect

    Rajesh, S.; Avinash, P.; Kerur, B. R.; Anilkumar, S.

    2015-08-28

    This study assesses the level of background radiation around Shorapur. The study region locates the western part of the Yadgir district of Karnataka. Shorapur and Shahapur talukas are mostly composed of clay, shale sandstone, granite rock and part of study area is black soil. Thirty sample locations were selected along the length and breadth of Shorapur and Shahapur taluka. Natural radionuclide activity concentrations in soil samples were determined using 4'X4' NaI (Tl) gamma spectroscopy. Outdoor gamma dose measurements in air at 1 m above ground level were determined using Rad Eye PRD survey meter. Estimated dose values are compared with the survey meter values and found to be good agreement between them and also with the data obtained from different other areas of Karnataka and India. The average values were found to be slightly higher in the present investigation.

  17. Simple lake breeze front position technique for off-site dose assessment

    SciTech Connect

    Burda, T.J.; Mazzola, C.A.

    1983-07-01

    During a lake/sea breeze an airflow trajectory reversal generally occurs at the leading edge (lake/sea breeze front) of the landward advancing marine air and can significantly affect the use of an off-site dose assessment procedure. Knowledge of the location of the lake/sea breeze front in real time is vital in interpreting the results from a conventional straightline Gaussian off-site dose calculation methodology, which ignores this complex flow pattern. A simple, low-cost technique was developed to estimate the location of the lake/sea breeze front in real time from easily obtainable meteorological parameters recorded at National Weather Service stations. Although this technique was developed for lake breezes occurring near the Wisconsin Public Service Kewaunee nuclear plant, the concept is applicable after site-specific modifications for other lakeshore sites in approximating the location of the lake breeze front.

  18. Numerical system utilising a Monte Carlo calculation method for accurate dose assessment in radiation accidents.

    PubMed

    Takahashi, F; Endo, A

    2007-01-01

    A system utilising radiation transport codes has been developed to derive accurate dose distributions in a human body for radiological accidents. A suitable model is quite essential for a numerical analysis. Therefore, two tools were developed to setup a 'problem-dependent' input file, defining a radiation source and an exposed person to simulate the radiation transport in an accident with the Monte Carlo calculation codes-MCNP and MCNPX. Necessary resources are defined by a dialogue method with a generally used personal computer for both the tools. The tools prepare human body and source models described in the input file format of the employed Monte Carlo codes. The tools were validated for dose assessment in comparison with a past criticality accident and a hypothesized exposure.

  19. Assessing measurement uncertainty in meteorology in urban environments

    NASA Astrophysics Data System (ADS)

    Curci, S.; Lavecchia, C.; Frustaci, G.; Paolini, R.; Pilati, S.; Paganelli, C.

    2017-10-01

    Measurement uncertainty in meteorology has been addressed in a number of recent projects. In urban environments, uncertainty is also affected by local effects which are more difficult to deal with than for synoptic stations. In Italy, beginning in 2010, an urban meteorological network (Climate Network®) was designed, set up and managed at national level according to high metrological standards and homogeneity criteria to support energy applications. The availability of such a high-quality operative automatic weather station network represents an opportunity to investigate the effects of station siting and sensor exposure and to estimate the related measurement uncertainty. An extended metadata set was established for the stations in Milan, including siting and exposure details. Statistical analysis on an almost 3-year-long operational period assessed network homogeneity, quality and reliability. Deviations from reference mean values were then evaluated in selected low-gradient local weather situations in order to investigate siting and exposure effects. In this paper the methodology is depicted and preliminary results of its application to air temperature discussed; this allowed the setting of an upper limit of 1 °C for the added measurement uncertainty at the top of the urban canopy layer.

  20. Water Environment of Kochi - Risk and Impacts Assessment

    NASA Astrophysics Data System (ADS)

    M S, M.; A N, B.

    2007-12-01

    The southwest coast of India is known for its maritime tropical climate which encompasses the Summer Monsoon and resultant land runoff. The Kochi region receives vast amount of rainfall in a short spell of four months (June-September) and for the given terrain characteristics, approximately 70% escapes to the Arabian Sea. The dry season (January-May) is deficit in water resources when the demands are equally high. Superimposed on this natural cycle, the land use changes, alterations in agricultural pattern, deforestation and water regulation along with ill effects of urbanization and industrialization has lead to grave negative impacts in the water environment. A vivid picture is drawn on the environmental setting of this region placing due emphasize on water resources, water quality and community services and resource management versus impacts. Critical areas such as balancing water surplus against deficit, quality maintenance against health scenario and issues in policy making for the water regime in Kochi region is assessed in terms of embedded risks.

  1. Assessment of Regional Pediatric Computed Tomography Dose Indices in Tamil Nadu

    PubMed Central

    Saravanakumar, A.; Vaideki, K.; Govindarajan, K. N.; Jayakumar, S.; Devanand, B.

    2017-01-01

    The aim of this article is to assess Tamil Nadu pediatric computed tomography (CT) diagnostic reference levels (DRLs) by collecting radiation dose data for the most commonly performed CT examinations. This work was performed for thirty CT scanners installed in various parts of the Tamil Nadu region. The patient cohort was divided into two age groups: <1 year, and 1–5 years. CT dose indices were measured using a 10 cm3 pencil ion chamber with pediatric head and body polymethyl methacrylate phantoms. Dose data such as volumetric CT dose index (CTDIv) and dose length product (DLP) on a minimum of twenty average-sized pediatric patients in each category were recorded to calculate a mean site CTDIv and DLP value. The rounded 75th percentile was used to calculate a pediatric DRL for each hospital, and then region by compiling all results. Data were collected for 3600 pediatric patients. Pediatric CT DRL for two age groups: <1 year (CTDIv and DLP of head [20 mGy, 352 mGy.cm], chest [7 mGy, 120 mGy.cm] and abdomen [12 mGy, 252 mGy.cm]), and 1–5 years (CTDIv and DLP of head [38 mGy, 505 mGy.cm], chest [8 mGy, 132 mGy.cm] and abdomen [14 mGy, 270 mGy.cm]) for select procedures have been calculated. Proposed pediatric DRLs of CTDIv and DLP for head procedure were lower, and for chest and abdomen procedures were higher than European pediatric DRLs for both age groups. PMID:28405108

  2. Assessment of dose error due to nylon mesh of treatment couch.

    PubMed

    Gul, Attia; Liaquat, Mehnaz; Kanwal, Aneela; Abbasi, Nadeem Zia; Kakakhel, Muhammad Basim; Ali, Akbar

    2015-12-01

    This study aims at the assessment of dose error in patients undergoing radiotherapy due to treatment couch of Co-60 teletherapy unit. In this study beam attenuation due to treatment couch of Co-60 unit was measured in air for different gantry angles and field sizes. Polymethylmethacrylate (PMMA) phantom was used to estimate the effect of depth on attenuation. Impact of couch on surface dose was also evaluated. Beam attenuation due to couch was in the range of 0.5-28% for different gantry angles with standard field size of 10 × 10 cm(2) with optimum position of metallic cranks. Maximum attenuation (29%) was observed with smallest field size i.e. 5 × 5 cm(2). Beam attenuation has been found higher in phantom as compared to that in air However, no particular trend of attenuation has been noted with varying depth of phantom. A 6% increase in surface dose has also been observed due to couch insertion for normal beam incidence. Maximum error of 80% is also note-worthy for most unfavorable situation of irradiation at 180 degree through the metallic cranks. It has been determined that ignoring the treatment couch and its accessories can result in dose error of 0.5-80%, depending on gantry angle, field size and position of couch accessories. Therefore, consideration of dose error due to couch during treatment planning is recommended. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  3. Assessment of The Dose-Response Relationship of Radiation-Induced Bystander Effect in Two Cell Lines Exposed to High Doses of Ionizing Radiation (6 and 8 Gy)

    PubMed Central

    Bahreyni Toossi, Mohammad Taghi; Khademi, Sara; Azimian, Hosein; Mohebbi, Shokoufeh; Soleymanifard, Shokouhozaman

    2017-01-01

    Objective The dose-response relationship of radiation-induced bystander effect (RIBE) is controversial at high dose levels. The aim of the present study is to assess RIBE at high dose levels by examination of different endpoints. Materials and Methods This experimental study used the medium transfer technique to induce RIBE. The cells were divided into two main groups: QU-DB cells which received medium from autologous irradiated cells and MRC5 cells which received medium from irradiated QU-DB cells. Colony, MTT, and micronucleus assays were performed to quantify bystander responses. The medium was diluted and transferred to bystander cells to investigate whether medium dilution could revive the RIBE response that disappeared at a high dose. Results The RIBE level in QU-DB bystander cells increased in the dose range of 0.5 to 4 Gy, but decreased at 6 and 8 Gy. The Micronucleated cells per 1000 binucleated cells (MNBN) frequency of QU-DB bystander cells which received the most diluted medium from 6 and 8 Gy QU-DB irradiated cells reached the maximum level compared to the MNBN frequency of the cells that received complete medium (P<0.0001). MNBN frequency of MRC5 cells which received the most diluted medium from 4 Gy QU-DB irradiated cells reached the maximum level compared to MNBN frequency of cells that received complete medium (P<0.0001). Conclusion Our results showed that RIBE levels decreased at doses above 4 Gy; however, RIBE increased when diluted conditioned medium was transferred to bystander cells. This finding confirmed that a negative feedback mechanism was responsible for the decrease in RIBE response at high doses. Decrease of RIBE at high doses might be used to predict that in radiosurgery, brachytherapy and grid therapy, in which high dose per fraction is applied, normal tissue damage owing to RIBE may decrease. PMID:28836405

  4. Assessment of The Dose-Response Relationship of Radiation-Induced Bystander Effect in Two Cell Lines Exposed to High Doses of Ionizing Radiation (6 and 8 Gy).

    PubMed

    Bahreyni Toossi, Mohammad Taghi; Khademi, Sara; Azimian, Hosein; Mohebbi, Shokoufeh; Soleymanifard, Shokouhozaman

    2017-10-01

    The dose-response relationship of radiation-induced bystander effect (RIBE) is controversial at high dose levels. The aim of the present study is to assess RIBE at high dose levels by examination of different endpoints. This experimental study used the medium transfer technique to induce RIBE. The cells were divided into two main groups: QU-DB cells which received medium from autologous irradiated cells and MRC5 cells which received medium from irradiated QU-DB cells. Colony, MTT, and micronucleus assays were performed to quantify bystander responses. The medium was diluted and transferred to bystander cells to investigate whether medium dilution could revive the RIBE response that disappeared at a high dose. The RIBE level in QU-DB bystander cells increased in the dose range of 0.5 to 4 Gy, but decreased at 6 and 8 Gy. The Micronucleated cells per 1000 binucleated cells (MNBN) frequency of QU-DB bystander cells which received the most diluted medium from 6 and 8 Gy QU-DB irradiated cells reached the maximum level compared to the MNBN frequency of the cells that received complete medium (P<0.0001). MNBN frequency of MRC5 cells which received the most diluted medium from 4 Gy QU-DB irradiated cells reached the maximum level compared to MNBN frequency of cells that received complete medium (P<0.0001). Our results showed that RIBE levels decreased at doses above 4 Gy; however, RIBE increased when diluted conditioned medium was transferred to bystander cells. This finding confirmed that a negative feedback mechanism was responsible for the decrease in RIBE response at high doses. Decrease of RIBE at high doses might be used to predict that in radiosurgery, brachytherapy and grid therapy, in which high dose per fraction is applied, normal tissue damage owing to RIBE may decrease.

  5. Assessment of Radionuclides in the Savannah River Site Environment Summary

    SciTech Connect

    Carlton, W.H.

    1999-01-26

    This document summarizes the impact of radionuclide releases from Savannah River Site (SRS) facilities from 1954 through 1996. The radionuclides reported here are those whose release resulted in the highest dose to people living near SRS.

  6. Initial assessment of image quality for low-dose PET: evaluation of lesion detectability

    NASA Astrophysics Data System (ADS)

    Schaefferkoetter, Joshua D.; Yan, Jianhua; Townsend, David W.; Conti, Maurizio

    2015-07-01

    In the context of investigating the potential of low-dose PET imaging for screening applications, we developed methods to assess small lesion detectability as a function of the number of counts in the scan. We present here our methods and preliminary validation using tuberculosis cases. FDG-PET data from seventeen patients presenting diffuse hyper-metabolic lung lesions were selected for the study, to include a wide range of lesion sizes and contrasts. Reduced doses were simulated by randomly discarding events in the PET list mode, and ten realizations at each simulated dose were generated and reconstructed. The data were grouped into 9 categories determined by the number of included true events, from  >40 M to  <250 k counts. The images reconstructed from the original full statistical set were used to identify lung lesions, and each was, at every simulated dose, quantified by 6 parameters: lesion metabolic volume, lesion-to-background contrast, mean lesion tracer uptake, standard deviation of activity measurements (across realizations), lesion signal-to-noise ratio (SNR), and Hotelling observer SNR. Additionally, a lesion-detection task including 550 images was presented to several experienced image readers for qualitative assessment. Human observer performances were ranked using receiver operating characteristic analysis. The observer results were correlated with the lesion image measurements and used to train mathematical observer models. Absolute sensitivities and specificities of the human observers, as well as the area under the ROC curve, showed clustering and performance similarities among images produced from 5 million or greater counts. The results presented here are from a clinically realistic but highly constrained experiment, and more work is needed to validate these findings with a larger patient population.

  7. The Use of Mode of Action Information in Risk Assessment: Quantitative Key Events/Dose-Response Framework for Modeling the Dose-Response for Key Events

    EPA Science Inventory

    The HESI RISK21 project formed the Dose-Response/Mode-of-Action Subteam to develop strategies for using all available data (in vitro, in vivo, and in silico) to advance the next-generation of chemical risk assessments. A goal of the Subteam is to enhance the existing Mode of Act...

  8. The Use of Mode of Action Information in Risk Assessment: Quantitative Key Events/Dose-Response Framework for Modeling the Dose-Response for Key Events

    EPA Science Inventory

    The HESI RISK21 project formed the Dose-Response/Mode-of-Action Subteam to develop strategies for using all available data (in vitro, in vivo, and in silico) to advance the next-generation of chemical risk assessments. A goal of the Subteam is to enhance the existing Mode of Act...

  9. Performance assessment of the BEBIG MultiSource® high dose rate brachytherapy treatment unit

    NASA Astrophysics Data System (ADS)

    Palmer, Antony; Mzenda, Bongile

    2009-12-01

    A comprehensive system characterisation was performed of the Eckert & Ziegler BEBIG GmbH MultiSource® High Dose Rate (HDR) brachytherapy treatment unit with an 192Ir source. The unit is relatively new to the UK market, with the first installation in the country having been made in the summer of 2009. A detailed commissioning programme was devised and is reported including checks of the fundamental parameters of source positioning, dwell timing, transit doses and absolute dosimetry of the source. Well chamber measurements, autoradiography and video camera analysis techniques were all employed. The absolute dosimetry was verified by the National Physical Laboratory, UK, and compared to a measurement based on a calibration from PTB, Germany, and the supplied source certificate, as well as an independent assessment by a visiting UK centre. The use of the 'Krieger' dosimetry phantom has also been evaluated. Users of the BEBIG HDR system should take care to avoid any significant bend in the transfer tube, as this will lead to positioning errors of the source, of up to 1.0 mm for slight bends, 2.0 mm for moderate bends and 5.0 mm for extreme curvature (depending on applicators and transfer tube used) for the situations reported in this study. The reason for these errors and the potential clinical impact are discussed. Users should also note the methodology employed by the system for correction of transit doses, and that no correction is made for the initial and final transit doses. The results of this investigation found that the uncorrected transit doses lead to small errors in the delivered dose at the first dwell position, of up to 2.5 cGy at 2 cm (5.6 cGy at 1 cm) from a 10 Ci source, but the transit dose correction for other dwells was accurate within 0.2 cGy. The unit has been mechanically reliable, and source positioning accuracy and dwell timing have been reproducible, with overall performance similar to other existing HDR equipment. The unit is capable of high

  10. Performance assessment of the BEBIG MultiSource high dose rate brachytherapy treatment unit.

    PubMed

    Palmer, Antony; Mzenda, Bongile

    2009-12-21

    A comprehensive system characterisation was performed of the Eckert & Ziegler BEBIG GmbH MultiSource High Dose Rate (HDR) brachytherapy treatment unit with an (192)Ir source. The unit is relatively new to the UK market, with the first installation in the country having been made in the summer of 2009. A detailed commissioning programme was devised and is reported including checks of the fundamental parameters of source positioning, dwell timing, transit doses and absolute dosimetry of the source. Well chamber measurements, autoradiography and video camera analysis techniques were all employed. The absolute dosimetry was verified by the National Physical Laboratory, UK, and compared to a measurement based on a calibration from PTB, Germany, and the supplied source certificate, as well as an independent assessment by a visiting UK centre. The use of the 'Krieger' dosimetry phantom has also been evaluated. Users of the BEBIG HDR system should take care to avoid any significant bend in the transfer tube, as this will lead to positioning errors of the source, of up to 1.0 mm for slight bends, 2.0 mm for moderate bends and 5.0 mm for extreme curvature (depending on applicators and transfer tube used) for the situations reported in this study. The reason for these errors and the potential clinical impact are discussed. Users should also note the methodology employed by the system for correction of transit doses, and that no correction is made for the initial and final transit doses. The results of this investigation found that the uncorrected transit doses lead to small errors in the delivered dose at the first dwell position, of up to 2.5 cGy at 2 cm (5.6 cGy at 1 cm) from a 10 Ci source, but the transit dose correction for other dwells was accurate within 0.2 cGy. The unit has been mechanically reliable, and source positioning accuracy and dwell timing have been reproducible, with overall performance similar to other existing HDR equipment. The unit is capable of high

  11. Virtual environment for assessment of neurocognitive functioning: virtual reality cognitive performance assessment test.

    PubMed

    Parsons, Thomas D; Silva, Teri M; Pair, Jarrell; Rizzo, Albert A

    2008-01-01

    While standard neuropsychological measures have been found to have adequate predictive value, their ecological validity may diminish predictions about real world functioning. Virtual environments (VEs) are increasingly recognized as ecologically valid tools for neuropsychological assessment. We aim to develop a VE-based neuropsychological battery delivered within the context of a virtual city: Virtual Reality Cognitive Performance Assessment Test (VRCPAT). The 15 minute VRCPAT battery and 1.5 hour in-person neuropsychological assessment were conducted with a sample of 40 healthy adults, between the ages of 21 and 36, that included equivalent distributions of men and women from ethnically diverse populations. No subjects had history of psychiatric or neurologic conditions. Results supported both convergent and discriminant validity. The VRCPAT was found to correlate significantly with traditional neuropsychological tests assessing similar target constructs. No significant correlations existed between VRCPAT measures and non-target constructs. Findings suggest that the VRCPAT measures a capacity consistent with that of traditional neurocognitive measures; and is inconsistent with potential confounds. We conclude that the VRCPAT provides a unique opportunity to reliably and efficiently study neurocognitive function within an ecologically valid environment.

  12. "The Dose Makes the Poison": Informing Consumers About the Scientific Risk Assessment of Food Additives.

    PubMed

    Bearth, Angela; Cousin, Marie-Eve; Siegrist, Michael

    2016-01-01

    Intensive risk assessment is required before the approval of food additives. During this process, based on the toxicological principle of "the dose makes the poison,ˮ maximum usage doses are assessed. However, most consumers are not aware of these efforts to ensure the safety of food additives and are therefore sceptical, even though food additives bring certain benefits to consumers. This study investigated the effect of a short video, which explains the scientific risk assessment and regulation of food additives, on consumers' perceptions and acceptance of food additives. The primary goal of this study was to inform consumers and enable them to construct their own risk-benefit assessment and make informed decisions about food additives. The secondary goal was to investigate whether people have different perceptions of food additives of artificial (i.e., aspartame) or natural origin (i.e., steviolglycoside). To attain these research goals, an online experiment was conducted on 185 Swiss consumers. Participants were randomly assigned to either the experimental group, which was shown a video about the scientific risk assessment of food additives, or the control group, which was shown a video about a topic irrelevant to the study. After watching the video, the respondents knew significantly more, expressed more positive thoughts and feelings, had less risk perception, and more acceptance than prior to watching the video. Thus, it appears that informing consumers about complex food safety topics, such as the scientific risk assessment of food additives, is possible, and using a carefully developed information video is a successful strategy for informing consumers. © 2015 Society for Risk Analysis.

  13. Protection of the environment: how to position radioprotection in an ecological risk assessment perspective.

    PubMed

    Bréchignac, François

    2003-05-20

    The development of a system capable of ensuring adequate protection of the environment from the harmful effects of ionising radiation is at present particularly debated. This need comes both from a restrictive consideration of the environment in the so far existing system for human radioprotection, and the planetary-wide growing concerns about man's technogenic influence on his environment which have yielded 'sustainability' and 'precaution' as guiding principles for environmental protection. Whilst evolving from the field of human radioprotection, the radioprotection of the environment needs to be discussed in a wider perspective, with particular emphasis on the most advanced concepts which emerge from the efforts to deriving improved approaches to Ecological Risk Assessment. For the sake of protection, the environment is traditionally addressed through its biota since these are the sensitive components of ecosystems. Similarities between man and biotas reflect the ubiquitous mechanistic effects of radiation on life which disrupt molecules. However, important differences also arise in a number of perspectives, from the large spectrum of different species of biotas to their hierarchical self-organisation as interacting populations within ecosystems. Altogether, these aspects are prone to promote complex arrays of different responses to stress which lie beyond the scope of human radioprotection due to its focus on individuals of a single species. By means of selected illustrations, this paper reviews and discusses the current challenges faced in proper identification of measurable effect endpoints (stochastic/deterministic, individual/population- or ecosystem-relevant), dose limits in chronic exposure (or levels of concern), and their consideration according to radiation type (RBE) and interactions with other contaminants (synergies/antagonisms) which represent critical gaps in knowledge. The system of human radioprotection has conceptually been targeted at limiting

  14. Iodine-129: Environmental monitoring and population dose in the Hanford environs

    SciTech Connect

    Jaquish, R.E.; Price, K.R.

    1988-09-01

    Iodine-129 is an important radionuclide to be considered in environmental monitoring programs in the vicinity of fuel reprocessing plants. Because of its long half-life, 1.6 /times/ 10 /sup 7/ year, and active behavior in biological and environmental systems, it has the potential for accumulating in the environment from long-term, chronic releases. When the PUREX Plant at Hanford restarted reprocessing fuel in 1983, monitoring for /sup 129/I was included in the environmental monitoring program conducted by Pacific Northwest Laboratory (PNL). Low levels of /sup 129/I have access to environmental pathways from past airborne releases, current releases to the atmosphere, and ground-water seepage into the Columbia River. 4 refs., 2 figs., 1 tab.

  15. The assessment of antibody affinity distribution by thiocyanate elution: a simple dose-response approach.

    PubMed

    Ferreira, M U; Katzin, A M

    1995-12-01

    We describe a simple dose-response approach to assess the affinity distribution of polyclonal antibodies. The proportion of antigen-specific antibodies dissociated by increasing concentrations of the mild chaotropic agent ammonium thiocyanate (NH4SCN) was measured by enzyme immunoassay, and the distribution of tolerances to this agent was presented in a histogram form. Such 'tolerance distribution', which is analogous to that described in classical dose-response bioassays, is proposed as a representation of the actual antibody affinity distribution. To test this approach, we assessed affinity maturation patterns of anti-Plasmodium falciparum IgG antibodies in paired sera obtained from 22 malaria patients during the acute infection and convalescence. We obtained patterns of antibody affinity distributions consistent with those previously described in immunization experiments with the aid of more complex laboratory and computational approaches. Therefore, we suggest the thiocyanate elution technique as an alternative method for rapid assessment of affinity distributions of polyclonal antibodies elicited against complex antigens, readily applicable to large number of serum samples.

  16. SU-E-T-616: Plan Quality Assessment of Both Treatment Planning System Dose and Measurement-Based 3D Reconstructed Dose in the Patient

    SciTech Connect

    Olch, A

    2015-06-15

    Purpose: Systematic radiotherapy plan quality assessment promotes quality improvement. Software tools can perform this analysis by applying site-specific structure dose metrics. The next step is to similarly evaluate the quality of the dose delivery. This study defines metrics for acceptable doses to targets and normal organs for a particular treatment site and scores each plan accordingly. The input can be the TPS or the measurement-based 3D patient dose. From this analysis, one can determine whether the delivered dose distribution to the patient receives a score which is comparable to the TPS plan score, otherwise replanning may be indicated. Methods: Eleven neuroblastoma patient plans were exported from Eclipse to the Quality Reports program. A scoring algorithm defined a score for each normal and target structure based on dose-volume parameters. Each plan was scored by this algorithm and the percentage of total possible points was obtained. Each plan also underwent IMRT QA measurements with a Mapcheck2 or ArcCheck. These measurements were input into the 3DVH program to compute the patient 3D dose distribution which was analyzed using the same scoring algorithm as the TPS plan. Results: The mean quality score for the TPS plans was 75.37% (std dev=14.15%) compared to 71.95% (std dev=13.45%) for the 3DVH dose distribution. For 3/11 plans, the 3DVH-based quality score was higher than the TPS score, by between 0.5 to 8.4 percentage points. Eight/11 plans scores decreased based on IMRT QA measurements by 1.2 to 18.6 points. Conclusion: Software was used to determine the degree to which the plan quality score differed between the TPS and measurement-based dose. Although the delivery score was generally in good agreement with the planned dose score, there were some that improved while there was one plan whose delivered dose quality was significantly less than planned. This methodology helps evaluate both planned and delivered dose quality. Sun Nuclear Corporation has

  17. Assessment of environment impacts of egg production chain using life cycle assessment.

    PubMed

    Ghasempour, Atena; Ahmadi, Ebrahim

    2016-12-01

    In this study we have to deal with the assessment of environment impacts of laying hen in the Alborz province, Iran. This assessment was carried out for one kg of egg during a period of 420 days for 1000 chickens. Then due to significant consumption of diet during period of question, three main products including corn, soybean and wheat which are consist of 80 percent of the combination of laying chicken diet, also collected the information about their production and it has been evaluated the indicators of their environment individually and eventually, the results has been considered as a title for inputs of poultry. Data for production of inputs were taken from EcoInvent 2.0 database, and SimaPro software was used for analysis. Ten classification impacts including Abiotic Depletion potential, Acidification potential, Eutrophication potential, Global Warming potential for time horizon 100 years, Ozone Depletion potential, Human Toxicity potential, Freshwater and Marine Aquatic Eco-toxicity potential, Terrestrial Eco-toxicity potential, and Photochemical Oxidation potential were selected based on the CML 2 baseline 2000 V2/world, 1990/characterization method. Due to the results, for each kilograms of egg, 30/09 MJ and also the value of greenhouse gas emissions is 4/07 Kg CO2 eq was calculated. According to the obtained results, the production of diet has made the most negative charge of environment among the inputs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Erosion risk assessment of active coastal cliffs in temperate environments

    NASA Astrophysics Data System (ADS)

    Del Río, Laura; Gracia, F. Javier

    2009-11-01

    The potentially negative consequences resulting from cliff recession are a matter of serious concern in many coastal areas worldwide. The assessment of such processes has traditionally been performed by calculating average cliff recession rates and projecting them into the future, without taking into consideration the diverse factors affecting cliff dynamics and stability. In this work a new, practical method is presented to evaluate cliff erosion risk in temperate environments, by analysing the main factors responsible for both the physical and the socioeconomic aspects of erosion, representing cliff loss potential and damage potential, respectively. For this purpose an integration of 11 physical variables (such as cliff lithology, beach characteristics or rainfall regime) and 6 socioeconomic variables (such as land use type or population density) is proposed. These variables are weighted and combined into a Hazard Index and an Impact Index, which in turn are merged into a composite Risk Index where the resulting values are normalized and expressed as a percentage of the maximum theoretical risk. The method is tested and validated by using data about cliff retreat rates and mass movement processes in the coast of Cádiz province (SW Spain). The proposed approach allows the zoning of coastal cliffs according to the risk, hazard and/or impact levels, including the recognition of critical areas where specific intervention strategies should be adopted. The method presented in this work is deemed both practical and scientifically valid, without requiring extensive and detailed surveys of the area where it is to be applied. This way, it constitutes an easy to use, valuable tool for decision-making regarding land use planning and management strategies for active coastal cliffs.

  19. Assessment of indoor environment in Paris child day care centers.

    PubMed

    Roda, Célina; Barral, Sophie; Ravelomanantsoa, Hanitriniala; Dusséaux, Murielle; Tribout, Martin; Le Moullec, Yvon; Momas, Isabelle

    2011-11-01

    Children are sensitive to indoor environmental pollution. Up until now there has been a lack of data on air quality in child day care centers. The aim of this study is to document the indoor environment quality of Paris child day care centers by repeated measurements, and to compare pollutant levels in child day care centers with levels in Paris dwellings. We selected 28 child day care centers frequented by a random sample of babies who participated in the PARIS birth cohort environmental investigation, and visited the child day care centers for one week twice in one year. Biological contaminants assessed were fungi, endotoxin, dust mite allergens, and chemical pollutants: aldehydes, volatile organic compounds and nitrogen dioxide (NO2). Relative humidity, temperature, and carbon dioxide levels were measured simultaneously. A standardized questionnaire was used to gather information about the buildings and their inhabitants. Airborne endotoxin levels in child day care centers were higher than those found in Paris dwellings. Dust mite allergens in child day care centers were below the threshold level for sensitization in the majority of samples, and in common with dwelling samples. Penicillium and Cladosporium were the most commonly identified genera fungi. The child day care center indoor/outdoor ratio for most chemical pollutants was above unity except for NO2, the levels for NO2 being significantly higher than those measured in homes. Chemical and biological contamination in child day care centers appears to be low, apart from endotoxin and NO2. Failure to take child exposure in child day care centers into account could result in an overestimation of children's exposure to other pollutants. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Assessment of Dose to the Nursing Infant from Radionuclides in Breast Milk

    SciTech Connect

    Leggett, Richard Wayne; Eckerman, Keith F

    2010-03-01

    A computer software package was developed to predict tissue doses to an infant due to intake of radionuclides in breast milk based on bioassay measurements and exposure data for the mother. The package is intended mainly to aid in decisions regarding the safety of breast feeding by a mother who has been acutely exposed to a radionuclide during lactation or pregnancy, but it may be applied to previous intakes during the mother s adult life. The package includes biokinetic and dosimetric information needed to address intake of Co-60, Sr-90, Cs-134, Cs-137, Ir-192, Pu-238, Pu-239, Am-241, or Cf-252 by the mother. It has been designed so that the library of biokinetic and dosimetric files can be expanded to address a more comprehensive set of radionuclides without modifying the basic computational module. The methods and models build on the approach used in Publication 95 of the International Commission on Radiological Protection (ICRP 2004), Doses to Infants from Ingestion of Radionuclides in Mothers Milk . The software package allows input of case-specific information or judgments such as chemical form or particle size of an inhaled aerosol. The package is expected to be more suitable than ICRP Publication 95 for dose assessment for real events or realistic planning scenarios in which measurements of the mother s excretion or body burden are available.

  1. Dose assessment of SiC nanoparticle dispersions during in vitro assays

    NASA Astrophysics Data System (ADS)

    Mejia, Jorge; Piret, Jean-Pascal; Noël, Florence; Masereel, Bernard; Toussaint, Olivier; Lucas, Stéphane

    2013-08-01

    Here, we show that key physicochemical parameters of commercial Silicon Carbide nanoparticles, such as the primary particles of about 53 nm in size, the agglomerates size, and the surface composition, are considerably modified with respect to the pristine conditions, during in vitro assessment. The use of sample conditioning stages, such as the pre-dispersion in aqueous media and the subsequent dispersion in a culture medium specific to the in vitro assay, produce modifications as the absorption of N, C, and O, from the culture medium, in the nanoparticles surface. Our results show that the sedimented dose, fraction of sedimented NPs during incubation and consequently in contact with cells seeded at the bottom, of Silicon Carbide nanoparticles can be measured from the particle size distribution obtained using a centrifugal liquid sedimentation technique. It is underlined that the variations observed in the physicochemical properties are related to the in vitro assay conditions. Culture medium and incubation time are found to influence the most the sedimented dose and consequently the cells dose uptake.

  2. Radiological dose assessment of the disposal of NORM wastes via landspreading.

    SciTech Connect

    Smith, K. P.

    1998-12-18

    Petroleum production activities sometimes result in the accumulation of naturally occurring radioactive materials (NORM) at elevated concentrations in by-product waste streams, such as scale and sludge. In the past, the petroleum industry commonly disposed of these wastes via landspreading, a practice consisting of spreading the waste over the soil surface and, sometimes, mixing it into the top layer of soil. Potential radiological doses to workers and the general public from landspreading of NORM waste have been assessed for a variety of scenarios, including the landspreading worker scenario and future residential, industrial, recreational, and agricultural scenarios. The exposure pathways evaluated include external radiation, inhalation of resuspended dust and radon, ingestion of soil and groundwater, and ingestion of contaminated foodstuff grown on the property. In general, potential doses to landspreading workers and members of the general public exposed through future recreational or agricultural use of the property are negligible. Potential doses to future residential or industrial users can vary greatly, depending on such factors as type of building construction, presence or absence of clean cover material, and on-site erosion rates. On the basis of the results presented in this paper, it is recommended that (a) any landspreading activity that would result in radium-226 concentrations in soil above 10 pCi/g be evaluated on a case-by-case basis to estimate potential future risk to the public and (b) states should consider policies to restrict future land use or advise future land owners where landspreading of NORM wastes has occurred.

  3. Image quality and dose assessment in digital breast tomosynthesis: A Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Baptista, M.; Di Maria, S.; Oliveira, N.; Matela, N.; Janeiro, L.; Almeida, P.; Vaz, P.

    2014-11-01

    Mammography is considered a standard technique for the early detection of breast cancer. However, its sensitivity is limited essentially due to the issue of the overlapping breast tissue. This limitation can be partially overcome, with a relatively new technique, called digital breast tomosynthesis (DBT). For this technique, optimization of acquisition parameters which maximize image quality, whilst complying with the ALARA principle, continues to be an area of considerable research. The aim of this work was to study the best quantum energies that optimize the image quality with the lowest achievable dose in DBT and compare these results with the digital mammography (DM) ones. Monte Carlo simulations were performed using the state-of-the-art computer program MCNPX 2.7.0 in order to generate several 2D cranio-caudal (CC) projections obtained during an acquisition of a standard DBT examination. Moreover, glandular absorbed doses and photon flux calculations, for each projection image, were performed. A homogeneous breast computational phantom with 50%/50% glandular/adipose tissue composition was used and two compressed breast thicknesses were evaluated: 4 cm and 8 cm. The simulated projection images were afterwards reconstructed with an algebraic reconstruction tool and the signal difference to noise ratio (SDNR) was calculated in order to evaluate the image quality in DBT and DM. Finally, a thorough comparison between the results obtained in terms of SDNR and dose assessment in DBT and DM was performed.

  4. An Audit Tool for Assessing the Learning Environment for Project 2000.

    ERIC Educational Resources Information Center

    Callaghan, Irene H.; McLafferty, Isabella H.

    1997-01-01

    Describes the development of an educational audit tool to assess the quality of the learning environment for nursing students in practice settings. The tool evaluates the physical environment, the learning climate, and students' perceptions. (SK)

  5. INEL historical dose evaluation: Reconstruction of operational airborne releases of radioactivity to the environment

    SciTech Connect

    Wenzel, D.R.; Peterson, H.K.; Dickson, R.L.

    1993-06-01

    Airborne releases of radioactivity from the operation of reactors and processes at the Idaho National Engineering Laboratory (INEL) since the early 1950s have been reconstructed. Operational releases discussed are those which are continuous and somewhat uniform over a period of time. The primary source of information on operational releases was the measurement of stack effluents as reported in the Radioactive Waste Management Information System (RWMIS) data base and technical reports. The data in the RWMIS data base is generally complete and reliable for releases that occurred since the early 1970s. Data for the 1960s was found to be less detailed and reflected less sophisticated monitoring instrumentation and record keeping systems. Data for the 1950s in general did not identify the specific mixture of radionuclides released. Operational releases of airborne radioactivity from the INEL, particularly in the early years of operation, have been reconstructed using current computer programs with reactor operating and fuel processing knowledge. Techniques used to reconstruct releases of airborne radioactivity to the environment from INEL operational releases and problems encountered are discussed.

  6. Emerging Patterns in Transferring Assessment Practices from F2f to Online Environments

    ERIC Educational Resources Information Center

    Beebe, Ronald; Vonderwell, Selma; Boboc, Marius

    2010-01-01

    This study explores the transfer of assessment practices from f2f to online environments by college instructors, with a particular interest in the factors influencing assessment in online learning settings. Assessment is a critical aspect of the learning environment, and considerable research has suggested various methods of formative and…

  7. Radiological dose assessment for residual radioactive material in soil at the clean slate sites 1, 2, and 3, Tonopah Test Range

    SciTech Connect

    1997-06-01

    A radiological dose assessment has been performed for Clean Slate Sites 1, 2, and 3 at the Tonopah Test Range, approximately 390 kilometers (240 miles) northwest of Las Vegas, Nevada. The assessment demonstrated that the calculated dose to hypothetical individuals who may reside or work on the Clean Slate sites, subsequent to remediation, does not exceed the limits established by the US Department of Energy for protection of members of the public and the environment. The sites became contaminated as a result of Project Roller Coaster experiments conducted in 1963 in support of the US Atomic Energy Commission (Shreve, 1964). Remediation of Clean Slate Sites 1, 2, and 3 is being performed to ensure that the 50-year committed effective dose equivalent to a hypothetical individual who lives or works on a Clean Slate site should not exceed 100 millirems per year. The DOE residual radioactive material guideline (RESRAD) computer code was used to assess the dose. RESRAD implements the methodology described in the DOE manual for establishing residual radioactive material guidelines (Yu et al., 1993a). In May and June of 1963, experiments were conducted at Clean Slate Sites 1, 2, and 3 to study the effectiveness of earth-covered structures for reducing the dispersion of nuclear weapons material as a result of nonnuclear explosions. The experiments required the detonation of various simulated weapons using conventional chemical explosives (Shreve, 1964). The residual radioactive contamination in the surface soil consists of weapons grade plutonium, depleted uranium, and their radioactive decay products.

  8. EOS low-dose radiography: a reliable and accurate upright assessment of lower-limb lengths.

    PubMed

    Escott, Benjamin G; Ravi, Bheeshma; Weathermon, Adam C; Acharya, Jay; Gordon, Christopher L; Babyn, Paul S; Kelley, Simon P; Narayanan, Unni G

    2013-12-04

    Children with lower-limb-length discrepancy require repeated radiographic assessment for monitoring and as a guide for management. The need for accurate assessment of length and alignment is balanced by the need to minimize radiation exposure. We compared the accuracy, reliability, and radiation dose of EOS, a novel low-dose upright biplanar radiographic imaging system, at two different settings, with that of conventional radiographs (teleoroentgenograms) and computed tomography (CT) scanograms, for the assessment of limb length. A phantom limb in a standardized position was assessed ten times with each of four d