Sample records for environment dose assessment

  1. PCBs: Cancer Dose-Response Assessment and Application to Environmental Mixtures (1996)

    EPA Science Inventory

    This report updates the cancer dose-response assessment for polychlorinated biphenyls (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. Processes that ch...

  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. 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.

  4. Dose assessment for marine biota and humans from discharge of (131)I to the marine environment and uptake by algae in Sydney, Australia.

    PubMed

    Carolan, Jessica Veliscek; Hughes, Catherine E; Hoffmann, Emmy L

    2011-10-01

    Iodine-131 reaches the marine environment through its excretion to the sewer by nuclear medicine patients followed by discharge through coastal and deepwater out falls. 131I has been detected in macroalgae,which bio-accumulate iodine, growing near the coastal out fall of Cronulla sewage treatment plant (STP) since 1995. During this study, (131)I levels in liquid effluent and sludge from three Sydney STP's as well as in macroalgae (Ulva sp. and Ecklonia radiata) growing near their shoreline out falls were measured. Concentration factors of 176 for Ulva sp. and 526 for E. radiata were derived. Radiation dose rates to marine biota from (131)I discharged to coastal waters calculated using the ERICA dose assessment tool were below the ERICA screening level of 10 μGy/hr. Radiation dose rates to humans from immersion in seawater or consumption of Ulva sp. containing (131)I were three and two orders of magnitude below the IAEA screening level of 10 μSv/year, respectively.

  5. Rapid Acute Dose Assessment Using MCNP6

    NASA Astrophysics Data System (ADS)

    Owens, Andrew Steven

    Acute radiation doses due to physical contact with a high-activity radioactive source have proven to be an occupational hazard. Multiple radiation injuries have been reported due to manipulating a radioactive source with bare hands or by placing a radioactive source inside a shirt or pants pocket. An effort to reconstruct the radiation dose must be performed to properly assess and medically manage the potential biological effects from such doses. Using the reference computational phantoms defined by the International Commission on Radiological Protection (ICRP) and the Monte Carlo N-Particle transport code (MCNP6), dose rate coefficients are calculated to assess doses for common acute doses due to beta and photon radiation sources. The research investigates doses due to having a radioactive source in either a breast pocket or pants back pocket. The dose rate coefficients are calculated for discrete energies and can be used to interpolate for any given energy of photon or beta emission. The dose rate coefficients allow for quick calculation of whole-body dose, organ dose, and/or skin dose if the source, activity, and time of exposure are known. Doses are calculated with the dose rate coefficients and compared to results from the International Atomic Energy Agency (IAEA) reports from accidents that occurred in Gilan, Iran and Yanango, Peru. Skin and organ doses calculated with the dose rate coefficients appear to agree, but there is a large discrepancy when comparing whole-body doses assessed using biodosimetry and whole-body doses assessed using the dose rate coefficients.

  6. Assessment of tritium in the Savannah River Site environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 fatemore » 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.« less

  7. 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.

  8. 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.

  9. 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

  10. Radioactivity Risk Assessment of Radon and Gamma Dose at One Uranium Tailings Pond in China

    NASA Astrophysics Data System (ADS)

    Lou, Yalong; Liu, Yong; Peng, Guowen; Zhao, Guodong; Zhang, Yan; Yang, Zhu

    2018-01-01

    A year-long monitoring of gamma radiation effective dose rate and radon concentration had been done in the reservoir area of one uranium tailings pond in Hunan province (The monitoring area included indoor and outdoor area of residential buildings and workshops, tailings dam slope). Afterwards, the annual effective radiation dose of the people in that radiation environment had been calculated based on the results of monitoring, as well as a radiation risk assessment. According to the assessment, gamma radiation effective dose rate and radon concentration in the monitoring area were low, and the annual effective radiation dose was far below the international standard (30mSv), which showed that the radiation would not put the people’s health at risk. However, the annual effective radiation dose of gamma was far above that of radon in the area of uranium tailings pond; therefore, it’s advisable to take quarantine measures in in the area of uranium tailings pond to keep the surrounding residents away from unnecessary ionizing radiation.

  11. 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.

  12. Modeling of an industrial environment: external dose calculations based on Monte Carlo simulations of photon transport.

    PubMed

    Kis, Zoltán; Eged, Katalin; Voigt, Gabriele; Meckbach, Reinhard; Müller, Heinz

    2004-02-01

    External gamma exposures from radionuclides deposited on surfaces usually result in the major contribution to the total dose to the public living in urban-industrial environments. The aim of the paper is to give an example for a calculation of the collective and averted collective dose due to the contamination and decontamination of deposition surfaces in a complex environment based on the results of Monte Carlo simulations. The shielding effects of the structures in complex and realistic industrial environments (where productive and/or commercial activity is carried out) were computed by the use of Monte Carlo method. Several types of deposition areas (walls, roofs, windows, streets, lawn) were considered. Moreover, this paper gives a summary about the time dependence of the source strengths relative to a reference surface and a short overview about the mechanical and chemical intervention techniques which can be applied in this area. An exposure scenario was designed based on a survey of average German and Hungarian supermarkets. In the first part of the paper the air kermas per photon per unit area due to each specific deposition area contaminated by 137Cs were determined at several arbitrary locations in the whole environment relative to a reference value of 8.39 x 10(-4) pGy per gamma m(-2). The calculations provide the possibility to assess the whole contribution of a specific deposition area to the collective dose, separately. According to the current results, the roof and the paved area contribute the most part (approximately 92%) to the total dose in the first year taking into account the relative contamination of the deposition areas. When integrating over 10 or 50 y, these two surfaces remain the most important contributors as well but the ratio will increasingly be shifted in favor of the roof. The decontamination of the roof and the paved area results in about 80-90% of the total averted collective dose in each calculated time period (1, 10, 50 y).

  13. Can we use the equivalent sphere model to approximate organ doses in space radiation environments?

    NASA Astrophysics Data System (ADS)

    Lin, Zi-Wei

    For space radiation protection one often calculates the dose or dose equivalent in blood forming organs (BFO). It has been customary to use a 5cm equivalent sphere to approximate the BFO dose. However, previous studies have concluded that a 5cm sphere gives a very different dose from the exact BFO dose. One study concludes that a 9cm sphere is a reasonable approximation for the BFO dose in solar particle event (SPE) environments. In this study we investigate the reason behind these observations and extend earlier studies by studying whether BFO, eyes or the skin can be approximated by the equivalent sphere model in different space radiation environments such as solar particle events and galactic cosmic ray (GCR) environments. We take the thickness distribution functions of the organs from the CAM (Computerized Anatomical Man) model, then use a deterministic radiation transport to calculate organ doses in different space radiation environments. The organ doses have been evaluated with a water or aluminum shielding from 0 to 20 g/cm2. We then compare these exact doses with results from the equivalent sphere model and determine in which cases and at what radius parameters the equivalent sphere model is a reasonable approximation. Furthermore, we propose to use a modified equivalent sphere model with two radius parameters to represent the skin or eyes. For solar particle events, we find that the radius parameters for the organ dose equivalent increase significantly with the shielding thickness, and the model works marginally for BFO but is unacceptable for eyes or the skin. For galactic cosmic rays environments, the equivalent sphere model with one organ-specific radius parameter works well for the BFO dose equivalent, marginally well for the BFO dose and the dose equivalent of eyes or the skin, but is unacceptable for the dose of eyes or the skin. The BFO radius parameters are found to be significantly larger than 5 cm in all cases, consistent with the conclusion of

  14. Assessment of radiocarbon in the Savannah River Site Environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    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.more » Releases of [sup 14]C have resulted in a negligible risk to the environment and the population it supports.« less

  15. Assessment of radiocarbon in the Savannah River Site Environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    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.more » Releases of {sup 14}C have resulted in a negligible risk to the environment and the population it supports.« less

  16. Dose assessment of aircraft crew in The Netherlands.

    PubMed

    Van Dijk, J W E

    2003-01-01

    As the operator of the National Dose Registration and Information System, NRG has implemented a system for radiation exposure monitoring for the Dutch airlines. The system is based on the use of computer generated flight plans together with dose calculations using the CARI-6M program. Before installing the system a study was performed to estimate the uncertainty in the assessment of the annual dose of the crew members. It was concluded that the proposed system complies with international recommendations on the uncertainty in dose assessments in individual monitoring and that the operational costs of the system are low.

  17. 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.

  18. Alteration in behavioral sensitivity to amphetamine after treatment with oxotremorine. Effect of dose and test environment.

    PubMed

    Gralewicz, Sławomir; Lutz, Piotr; Wiaderna, Dorota; Tomas, Tadeusz

    2003-12-17

    Our earlier experiment revealed that rats pretreated once with an anticholinesterase develop hyposensitivity to amphetamine (AMPH). One of the likely causes of this effect might be a transient hyperexcitation of the central muscarinic receptors. It has appeared, however, that rats pretreated with oxotremorine (OX), a muscarinic agonist, show an augmented behavioral response to AMPH weeks later. The present experiments were performed in order to obtain more information on the relationship between the OX-induced sensitization to AMPH and the OX dose and dosing regime (single or repeated), and to find out whether the environment associated with the acute effects of OX could affect the response to AMPH. In experiment 1, adult male rats were given a single i.p. injection of OX in home cages at a moderate (0.5 mg/kg) or high (1.0 mg/kg) dose. In experiment 2, the rats received eight 1.0 mg/kg doses of OX in the course of three days. After each injection, some animals returned to their home cages, and some were placed in the test cages for 30 min. In both experiments, the response to AMPH was assessed on day 21 after the treatment. The obtained results indicate that: (i) a single i.p. exposure to OX results in an increase of the rat's behavioral sensitivity to AMPH but the moderate dose is more effective in inducing this effect; (ii) repeated exposure to OX at high doses, in a regime enabling development of tolerance to the acute OX effects, does not alter the rat sensitivity to AMPH, and (iii) expression of the AMPH response is suppressed in environment which has been associated with acute effects of OX.

  19. Assessment of doses to game animals in Finland.

    PubMed

    Vetikko, Virve; Kostiainen, Eila

    2013-11-01

    A study was carried out to assess the dose rates to game animals in Finland affected by the radioactive caesium deposition that occurred after the accident at the Chernobyl nuclear power plant in Ukraine in 1986. The aim of this assessment was to obtain new information on the dose rates to mammals and birds under Finnish conditions. Dose rates were calculated using the ERICA Assessment Tool developed within the EC 6th Framework Programme. The input data consisted of measured activity concentrations of (137)Cs and (134)Cs in soil and lake water samples and in flesh samples of selected animal species obtained for environmental monitoring. The study sites were located in the municipality of Lammi, Southern Finland, where the average (137)Cs deposition was 46.5 kBq m(-2) (1 October 1987). The study sites represented the areas receiving the highest deposition in Finland after the Chernobyl accident. The selected species included moose (Alces alces), arctic hare (Lepus timidus) and several bird species: black grouse (Tetrao tetrix), hazel hen (Bonasia bonasia), mallard (Anas platurhynchos), goldeneye (Bucephala clangula) and teal (Anas crecca). For moose, dose rates were calculated for the years 1986-1990 and for the 2000s. For all other species, maximal measured activity concentrations were used. The results showed that the dose rates to these species did not exceed the default screening level of 10 μGy h(-1) used as a protection criterion. The highest total dose rate (internal and external summed), 3.7 μGy h(-1), was observed for the arctic hare in 1986. Although the dose rate of 3.7 μGy h(-1) cannot be considered negligible given the uncertainties involved in predicting the dose rates, the possible harmful effects related to this dose rate are too small to be assessed based on current knowledge on the biological effects of low doses in mammals. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    PubMed Central

    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. PMID:28804156

  1. 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.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    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.more » 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.« less

  3. 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.

  4. 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.

  5. 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...

  6. 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

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    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 ofmore » 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

  8. Results of nDOSE and HiDOSE Experiments for Dosimetric Evaluation During STS-134 Mission

    NASA Astrophysics Data System (ADS)

    Pugliese, M.; Loffredo, F.; Quarto, M.; Roca, V.; Mattone, C.; Borla, O.; Zanini, A.

    2014-07-01

    HiDOSE (Heavy ion DOSimetry Experiment) and nDOSE (neutron DOSimetry Experiment) experiments conducted as a part of BIOKIS (Biokon in Space) payload were designed to measure the dose equivalent due to charged particles and to neutron field, on the entire energy range, during STS-134 mission. Given the complexity of the radiation field in space environment, dose measurements should be considered an asset of any space mission, and for this reason HiDOSE and nDOSE experiments represent an important contribution to the radiation environment assessment during this mission, a short duration flight. The results of these experiments, obtained using Thermo Luminescence Dosimeters (TLDs) to evaluate the charged particles dosimetry and neutron bubbles dosimeters and stack bismuth track dosimeters for neutron dosimetry, indicate that the dose equivalent rate due to space radiation exposure during the STS-134 mission is in accordance with the results obtained from long duration flights.

  9. 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.

  10. 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.

  11. Radiological assessment. A textbook on environmental dose analysis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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. Themore » 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.« less

  12. SUDOQU, a new dose-assessment methodology for radiological surface contamination.

    PubMed

    van Dillen, Teun; van Dijk, Arjan

    2018-06-12

    A new methodology has been developed for the assessment of the annual effective dose resulting from removable and fixed radiological surface contamination. It is entitled SUDOQU (SUrface DOse QUantification) and it can for instance be used to derive criteria for surface contamination related to the import of non-food consumer goods, containers and conveyances, e.g., limiting values and operational screening levels. SUDOQU imposes mass (activity)-balance equations based on radioactive decay, removal and deposition processes in indoor and outdoor environments. This leads to time-dependent contamination levels that may be of particular importance in exposure scenarios dealing with one or a few contaminated items only (usually public exposure scenarios, therefore referred to as the 'consumer' model). Exposure scenarios with a continuous flow of freshly contaminated goods also fall within the scope of the methodology (typically occupational exposure scenarios, thus referred to as the 'worker model'). In this paper we describe SUDOQU, its applications, and its current limitations. First, we delineate the contamination issue, present the assumptions and explain the concepts. We describe the relevant removal, transfer, and deposition processes, and derive equations for the time evolution of the radiological surface-, air- and skin-contamination levels. These are then input for the subsequent evaluation of the annual effective dose with possible contributions from external gamma radiation, inhalation, secondary ingestion (indirect, from hand to mouth), skin contamination, direct ingestion and skin-contact exposure. The limiting effective surface dose is introduced for issues involving the conservatism of dose calculations. SUDOQU can be used by radiation-protection scientists/experts and policy makers in the field of e.g. emergency preparedness, trade and transport, exemption and clearance, waste management, and nuclear facilities. Several practical examples are

  13. Assessing the assessments: Pharmaceuticals in the environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Enick, O.V.; Moore, M.M.

    2007-11-15

    The relatively new issue of pharmaceutical contamination of the environment offers the opportunity to explore the application of values to the construction, communication and management of risk. The still-developing regulatory policies regarding environmental contamination with pharmaceuticals provide fertile ground for the introduction of values into the definition and management of risk. In this report, we summarize the current knowledge regarding pharmaceutical contamination of the environment and discuss specific attributes of pharmaceuticals that require special consideration. We then present an analysis showing that if values are incorporated into assessing, characterizing and managing risk, the results of risk assessments will more accuratelymore » reflect the needs of various stakeholders. Originating from an acknowledgement of the inherent uncertainty and value-laden nature of risk assessment, the precautionary principle (and later, the multi-criteria, integrated risk assessment), provides a direction for further research and policy development.« less

  14. Ecological risk assessment of depleted uranium in the environment at Aberdeen Proving Ground

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Clements, W.H.; Kennedy, P.L.; Myers, O.B.

    1993-01-01

    A preliminary ecological risk assessment was conducted to evaluate the effects of depleted uranium (DU) in the Aberdeen Proving Ground (APG) ecosystem and its potential for human health effects. An ecological risk assessment of DU should include the processes of hazard identification, dose-response assessment, exposure assessment, and risk characterization. Ecological risk assessments also should explicitly examine risks incurred by nonhuman as well as human populations, because risk assessments based only on human health do not always protect other species. To begin to assess the potential ecological risk of DU release to the environment we modeled DU transport through the principalmore » components of the aquatic ecosystem at APG. We focused on the APG aquatic system because of the close proximity of the Chesapeake Bay and concerns about potential impacts on this ecosystem. Our objective in using a model to estimate environmental fate of DU is to ultimately reduce the uncertainty about predicted ecological risks due to DU from APG. The model functions to summarize information on the structure and functional properties of the APG aquatic system, to provide an exposure assessment by estimating the fate of DU in the environment, and to evaluate the sources of uncertainty about DU transport.« less

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    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.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 Authorizedmore » 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

  17. 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 ...

  18. 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

  19. Automated size-specific CT dose monitoring program: assessing variability in CT dose.

    PubMed

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

    2012-11-01

    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. 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(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(adj) between scanner models and across institutions. 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(adj) that differed by up to 44% from effective dose estimates that were not adjusted by patient size

  20. Methods for Probabilistic Radiological Dose Assessment at a High-Level Radioactive Waste Repository.

    NASA Astrophysics Data System (ADS)

    Maheras, Steven James

    Methods were developed to assess and evaluate the uncertainty in offsite and onsite radiological dose at a high-level radioactive waste repository to show reasonable assurance that compliance with applicable regulatory requirements will be achieved. Uncertainty in offsite dose was assessed by employing a stochastic precode in conjunction with Monte Carlo simulation using an offsite radiological dose assessment code. Uncertainty in onsite dose was assessed by employing a discrete-event simulation model of repository operations in conjunction with an occupational radiological dose assessment model. Complementary cumulative distribution functions of offsite and onsite dose were used to illustrate reasonable assurance. Offsite dose analyses were performed for iodine -129, cesium-137, strontium-90, and plutonium-239. Complementary cumulative distribution functions of offsite dose were constructed; offsite dose was lognormally distributed with a two order of magnitude range. However, plutonium-239 results were not lognormally distributed and exhibited less than one order of magnitude range. Onsite dose analyses were performed for the preliminary inspection, receiving and handling, and the underground areas of the repository. Complementary cumulative distribution functions of onsite dose were constructed and exhibited less than one order of magnitude range. A preliminary sensitivity analysis of the receiving and handling areas was conducted using a regression metamodel. Sensitivity coefficients and partial correlation coefficients were used as measures of sensitivity. Model output was most sensitive to parameters related to cask handling operations. Model output showed little sensitivity to parameters related to cask inspections.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Carlton, W.H.; Evans, A.G.; Geary, L.A.

    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 nuclearmore » 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.« less

  2. LINKING EXPOSURES TO INTERNAL DOSES USING BIOMARKERS

    EPA Science Inventory

    Biomonitoring is a useful tool to help assess human exposures/internal doses to chemicals in the environment. This research contributes to EPA's mission to protect human health by understanding what chemicals people are exposed to in their daily environments. In this task, we wil...

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 ofmore » 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.« less

  4. Built environment assessment: Multidisciplinary perspectives.

    PubMed

    Glanz, Karen; Handy, Susan L; Henderson, Kathryn E; Slater, Sandy J; Davis, Erica L; Powell, Lisa M

    2016-12-01

    As obesity has become increasingly widespread, scientists seek better ways to assess and modify built and social environments to positively impact health. The applicable methods and concepts draw on multiple disciplines and require collaboration and cross-learning. This paper describes the results of an expert team׳s analysis of how key disciplinary perspectives contribute to environmental context-based assessment related to obesity, identifies gaps, and suggests opportunities to encourage effective advances in this arena. A team of experts representing diverse disciplines convened in 2013 to discuss the contributions of their respective disciplines to assessing built environments relevant to obesity prevention. The disciplines include urban planning, public health nutrition, exercise science, physical activity research, public health and epidemiology, behavioral and social sciences, and economics. Each expert identified key concepts and measures from their discipline, and applications to built environment assessment and action. A selective review of published literature and internet-based information was conducted in 2013 and 2014. The key points that are highlighted in this article were identified in 2014-2015 through discussion, debate and consensus-building among the team of experts. Results focus on the various disciplines׳ perspectives and tools, recommendations, progress and gaps. There has been significant progress in collaboration across key disciplines that contribute to studies of built environments and obesity, but important gaps remain. Using lessons from interprofessional education and team science, along with appreciation of and attention to other disciplines׳ contributions, can promote more effective cross-disciplinary collaboration in obesity prevention.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Christianson, Olav; Li Xiang; Frush, Donald

    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 CTmore » 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

  6. 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.

  7. TU-H-CAMPUS-JeP3-02: Automated Dose Accumulation and Dose Accuracy Assessment for Online Or Offline Adaptive Replanning

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, G; Ahunbay, E; Li, X

    Purpose: With introduction of high-quality treatment imaging during radiation therapy (RT) delivery, e.g., MR-Linac, adaptive replanning of either online or offline becomes appealing. Dose accumulation of delivered fractions, a prerequisite for the adaptive replanning, can be cumbersome and inaccurate. The purpose of this work is to develop an automated process to accumulate daily doses and to assess the dose accumulation accuracy voxel-by-voxel for adaptive replanning. Methods: The process includes the following main steps: 1) reconstructing daily dose for each delivered fraction with a treatment planning system (Monaco, Elekta) based on the daily images using machine delivery log file and consideringmore » patient repositioning if applicable, 2) overlaying the daily dose to the planning image based on deformable image registering (DIR) (ADMIRE, Elekta), 3) assessing voxel dose deformation accuracy based on deformation field using predetermined criteria, and 4) outputting accumulated dose and dose-accuracy volume histograms and parameters. Daily CTs acquired using a CT-on-rails during routine CT-guided RT for sample patients with head and neck and prostate cancers were used to test the process. Results: Daily and accumulated doses (dose-volume histograms, etc) along with their accuracies (dose-accuracy volume histogram) can be robustly generated using the proposed process. The test data for a head and neck cancer case shows that the gross tumor volume decreased by 20% towards the end of treatment course, and the parotid gland mean dose increased by 10%. Such information would trigger adaptive replanning for the subsequent fractions. The voxel-based accuracy in the accumulated dose showed that errors in accumulated dose near rigid structures were small. Conclusion: A procedure as well as necessary tools to automatically accumulate daily dose and assess dose accumulation accuracy is developed and is useful for adaptive replanning. Partially supported by Elekta

  8. 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

  9. 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.

  10. Dose estimates for the solid waste performance assessment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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/yrmore » 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.« less

  11. Nonparametric estimation of benchmark doses in environmental risk assessment

    PubMed Central

    Piegorsch, Walter W.; Xiong, Hui; Bhattacharya, Rabi N.; Lin, Lizhen

    2013-01-01

    Summary An important statistical objective in environmental risk analysis is estimation of minimum exposure levels, called benchmark doses (BMDs), that induce a pre-specified benchmark response in a dose-response experiment. In such settings, representations of the risk are traditionally based on a parametric dose-response model. It is a well-known concern, however, that if the chosen parametric form is misspecified, inaccurate and possibly unsafe low-dose inferences can result. We apply a nonparametric approach for calculating benchmark doses, based on an isotonic regression method for dose-response estimation with quantal-response data (Bhattacharya and Kong, 2007). We determine the large-sample properties of the estimator, develop bootstrap-based confidence limits on the BMDs, and explore the confidence limits’ small-sample properties via a short simulation study. An example from cancer risk assessment illustrates the calculations. PMID:23914133

  12. 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

  13. Dose assessment activities in the Republic of the Marshall Islands.

    PubMed

    Simon, S L; Graham, J C

    1996-10-01

    Dose assessments, both retrospective and prospective, comprise one important function of a radiological study commissioned by the Republic of the Marshall Islands (RMI) government in late 1989. Estimating past or future exposure requires the synthesis of information from historical data, results from a recently completed field monitoring program, laboratory measurements, and some experimental studies. Most of the activities in the RMI to date have emphasized a pragmatic rather than theoretical approach. In particular, most of the recent effort has been expended on conducting an independent radiological monitoring program to determine the degree of deposition and the geographical extent of weapons test fallout over the nation. Contamination levels on 70% of the land mass of the Marshall Islands were unknown prior to 1994. The environmental radioactivity data play an integral role in both retrospective and prospective assessments. One recent use of dose assessment has been to interpret environmental measurements of radioactivity into annual doses that might be expected at every atoll. A second use for dose assessment has been to determine compliance with a dose action level for the rehabilitation of Rongelap Island. Careful examination of exposure pathways relevant to the island lifestyle has been necessary to accommodate these purposes. Examples of specific issues studied include defining traditional island diets as well as current day variations, sources of drinking water, uses of tropical plants including those consumed for food and for medicinal purposes, the nature and microvariability of plutonium particles in the soil and unusual pathways of exposure, e.g., that which might be associated with cooking and washing outdoors and inadvertent soil ingestion. A study on the prevalence of thyroid disease is also being conducted and the geographic pattern of disease may be useful as a bioindicator of the geographic pattern of exposure to radioiodine. Finally, an

  14. Developability assessment of clinical drug products with maximum absorbable doses.

    PubMed

    Ding, Xuan; Rose, John P; Van Gelder, Jan

    2012-05-10

    Maximum absorbable dose refers to the maximum amount of an orally administered drug that can be absorbed in the gastrointestinal tract. Maximum absorbable dose, or D(abs), has proved to be an important parameter for quantifying the absorption potential of drug candidates. The purpose of this work is to validate the use of D(abs) in a developability assessment context, and to establish appropriate protocol and interpretation criteria for this application. Three methods for calculating D(abs) were compared by assessing how well the methods predicted the absorption limit for a set of real clinical candidates. D(abs) was calculated for these clinical candidates by means of a simple equation and two computer simulation programs, GastroPlus and an program developed at Eli Lilly and Company. Results from single dose escalation studies in Phase I clinical trials were analyzed to identify the maximum absorbable doses for these compounds. Compared to the clinical results, the equation and both simulation programs provide conservative estimates of D(abs), but in general D(abs) from the computer simulations are more accurate, which may find obvious advantage for the simulations in developability assessment. Computer simulations also revealed the complex behavior associated with absorption saturation and suggested in most cases that the D(abs) limit is not likely to be achieved in a typical clinical dose range. On the basis of the validation findings, an approach is proposed for assessing absorption potential, and best practices are discussed for the use of D(abs) estimates to inform clinical formulation development strategies. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. 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.…

  16. 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.

  17. Dose Assessments to the Hands of Radiopharmaceutical Workers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    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 radiopharmaceuticalsmore » 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.« less

  18. 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

  19. Entrance surface dose distribution and organ dose assessment for cone-beam computed tomography using measurements and Monte Carlo simulations with voxel phantoms

    NASA Astrophysics Data System (ADS)

    Baptista, M.; Di Maria, S.; Vieira, S.; Vaz, P.

    2017-11-01

    Cone-Beam Computed Tomography (CBCT) enables high-resolution volumetric scanning of the bone and soft tissue anatomy under investigation at the treatment accelerator. This technique is extensively used in Image Guided Radiation Therapy (IGRT) for pre-treatment verification of patient position and target volume localization. When employed daily and several times per patient, CBCT imaging may lead to high cumulative imaging doses to the healthy tissues surrounding the exposed organs. This work aims at (1) evaluating the dose distribution during a CBCT scan and (2) calculating the organ doses involved in this image guiding procedure for clinically available scanning protocols. Both Monte Carlo (MC) simulations and measurements were performed. To model and simulate the kV imaging system mounted on a linear accelerator (Edge™, Varian Medical Systems) the state-of-the-art MC radiation transport program MCNPX 2.7.0 was used. In order to validate the simulation results, measurements of the Computed Tomography Dose Index (CTDI) were performed, using standard PMMA head and body phantoms, with 150 mm length and a standard pencil ionizing chamber (IC) 100 mm long. Measurements for head and pelvis scanning protocols, usually adopted in clinical environment were acquired, using two acquisition modes (full-fan and half fan). To calculate the organ doses, the implemented MC model of the CBCT scanner together with a male voxel phantom ("Golem") was used. The good agreement between the MCNPX simulations and the CTDIw measurements (differences up to 17%) presented in this work reveals that the CBCT MC model was successfully validated, taking into account the several uncertainties. The adequacy of the computational model to map dose distributions during a CBCT scan is discussed in order to identify ways to reduce the total CBCT imaging dose. The organ dose assessment highlights the need to evaluate the therapeutic and the CBCT imaging doses, in a more balanced approach, and the

  20. Uncertainty of fast biological radiation dose assessment for emergency response scenarios.

    PubMed

    Ainsbury, Elizabeth A; Higueras, Manuel; Puig, Pedro; Einbeck, Jochen; Samaga, Daniel; Barquinero, Joan Francesc; Barrios, Lleonard; Brzozowska, Beata; Fattibene, Paola; Gregoire, Eric; Jaworska, Alicja; Lloyd, David; Oestreicher, Ursula; Romm, Horst; Rothkamm, Kai; Roy, Laurence; Sommer, Sylwester; Terzoudi, Georgia; Thierens, Hubert; Trompier, Francois; Vral, Anne; Woda, Clemens

    2017-01-01

    Reliable dose estimation is an important factor in appropriate dosimetric triage categorization of exposed individuals to support radiation emergency response. Following work done under the EU FP7 MULTIBIODOSE and RENEB projects, formal methods for defining uncertainties on biological dose estimates are compared using simulated and real data from recent exercises. The results demonstrate that a Bayesian method of uncertainty assessment is the most appropriate, even in the absence of detailed prior information. The relative accuracy and relevance of techniques for calculating uncertainty and combining assay results to produce single dose and uncertainty estimates is further discussed. Finally, it is demonstrated that whatever uncertainty estimation method is employed, ignoring the uncertainty on fast dose assessments can have an important impact on rapid biodosimetric categorization.

  1. [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.

  2. A Unified Probabilistic Framework for Dose-Response Assessment of Human Health Effects.

    PubMed

    Chiu, Weihsueh A; Slob, Wout

    2015-12-01

    When chemical health hazards have been identified, probabilistic dose-response assessment ("hazard characterization") quantifies uncertainty and/or variability in toxicity as a function of human exposure. Existing probabilistic approaches differ for different types of endpoints or modes-of-action, lacking a unifying framework. We developed a unified framework for probabilistic dose-response assessment. We established a framework based on four principles: a) individual and population dose responses are distinct; b) dose-response relationships for all (including quantal) endpoints can be recast as relating to an underlying continuous measure of response at the individual level; c) for effects relevant to humans, "effect metrics" can be specified to define "toxicologically equivalent" sizes for this underlying individual response; and d) dose-response assessment requires making adjustments and accounting for uncertainty and variability. We then derived a step-by-step probabilistic approach for dose-response assessment of animal toxicology data similar to how nonprobabilistic reference doses are derived, illustrating the approach with example non-cancer and cancer datasets. Probabilistically derived exposure limits are based on estimating a "target human dose" (HDMI), which requires risk management-informed choices for the magnitude (M) of individual effect being protected against, the remaining incidence (I) of individuals with effects ≥ M in the population, and the percent confidence. In the example datasets, probabilistically derived 90% confidence intervals for HDMI values span a 40- to 60-fold range, where I = 1% of the population experiences ≥ M = 1%-10% effect sizes. Although some implementation challenges remain, this unified probabilistic framework can provide substantially more complete and transparent characterization of chemical hazards and support better-informed risk management decisions.

  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. Technology Assessment and Roadmap for the Emergency Radiation Dose Assessment Program (ERDAP)

    DTIC Science & Technology

    2005-06-01

    l2O3:C OSL dosimeters . Overall design is based on similar systems described earlier by Justus et al. (1999) and Huston et al. (2001). Similar apparatus...Radioisotope Contamination 4. Pre-Positioned Physical Dosimeters C. Assessment of Emerging Dosimetry Technologies 1. Biological Measurements 2. Physico...architectures for radiation dose assessment tools. • Focus initial studies on defining the role of pre-positioned dosimeters , optimizing the size and

  5. Assessing doses to interventional radiologists using a personal dosimeter worn over a protective apron.

    PubMed

    Stranden, E; Widmark, A; Sekse, T

    2008-05-01

    Interventional radiologists receive significant radiation doses, and it is important to have simple methods for routine monitoring of their exposure. To evaluate the usefulness of a dosimeter worn outside the protective apron for assessments of dose to interventional radiologists. Assessments of effective dose versus dose to dosimeters worn outside the protective apron were achieved by phantom measurements. Doses outside and under the apron were assessed by phantom measurements and measurements on eight radiologists wearing two routine dosimeters for a 2-month period during ordinary working conditions. Finger doses for the same radiologists were recorded using thermoluminescent dosimeters (TLD; DXT-RAD Extremity dosimeters). Typical values for the ratio between effective dose and dosimeter dose were found to be about 0.02 when the radiologist used a thyroid shield and about 0.03 without. The ratio between the dose to the dosimeter under and outside a protective apron was found to be less than 0.04. There was very good correlation between finger dose and dosimeter dose. A personal dosimeter worn outside a protective apron is a good screening device for dose to the eyes and fingers as well as for effective dose, even though the effective dose is grossly overestimated. Relatively high dose to the fingers and eyes remains undetected by a dosimeter worn under the apron.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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) limitmore » 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.« less

  7. Ecological risk assessment of depleted uranium in the environment at Aberdeen Proving Ground. Annual report, 1991

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Clements, W.H.; Kennedy, P.L.; Myers, O.B.

    1993-03-01

    A preliminary ecological risk assessment was conducted to evaluate the effects of depleted uranium (DU) in the Aberdeen Proving Ground (APG) ecosystem and its potential for human health effects. An ecological risk assessment of DU should include the processes of hazard identification, dose-response assessment, exposure assessment, and risk characterization. Ecological risk assessments also should explicitly examine risks incurred by nonhuman as well as human populations, because risk assessments based only on human health do not always protect other species. To begin to assess the potential ecological risk of DU release to the environment we modeled DU transport through the principalmore » components of the aquatic ecosystem at APG. We focused on the APG aquatic system because of the close proximity of the Chesapeake Bay and concerns about potential impacts on this ecosystem. Our objective in using a model to estimate environmental fate of DU is to ultimately reduce the uncertainty about predicted ecological risks due to DU from APG. The model functions to summarize information on the structure and functional properties of the APG aquatic system, to provide an exposure assessment by estimating the fate of DU in the environment, and to evaluate the sources of uncertainty about DU transport.« less

  8. Radiation transport modeling and assessment to better predict radiation exposure, dose, and toxicological effects to human organs on long duration space flights.

    PubMed

    Denkins, P; Badhwar, G; Obot, V; Wilson, B; Jejelewo, O

    2001-01-01

    NASA is very interested in improving its ability to monitor and forecast the radiation levels that pose a health risk to space-walking astronauts as they construct the International Space Station and astronauts that will participate in long-term and deep-space missions. Human exploratory missions to the moon and Mars within the next quarter century, will expose crews to transient radiation from solar particle events which include high-energy galactic cosmic rays and high-energy protons. Because the radiation levels in space are high and solar activity is presently unpredictable, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. Today, numerous models have been developed and used to predict radiation exposure. Such a model is the Space Environment Information Systems (SPENVIS) modeling program, developed by the Belgian Institute for Space Aeronautics. SPENVIS, which has been assessed to be an excellent tool in characterizing the radiation environment for microelectronics and investigating orbital debris, is being evaluated for its usefulness with determining the dose and dose-equivalent for human exposure. Thus far. the calculations for dose-depth relations under varying shielding conditions have been in agreement with calculations done using HZETRN and PDOSE, which are well-known and widely used models for characterizing the environments for human exploratory missions. There is disagreement when assessing the impact of secondary radiation particles since SPENVIS does a crude estimation of the secondary radiation particles when calculating LET versus Flux. SPENVIS was used to model dose-depth relations for the blood-forming organs. Radiation sickness and cancer are life-threatening consequences resulting from radiation exposure. In space. exposure to radiation generally includes all of the critical organs. Biological and toxicological impacts have been included for discussion along with alternative risk mitigation

  9. Radiation transport modeling and assessment to better predict radiation exposure, dose, and toxicological effects to human organs on long duration space flights

    NASA Astrophysics Data System (ADS)

    Denkins, Pamela; Badhwar, Gautam; Obot, Victor; Wilson, Bobby; Jejelewo, Olufisayo

    2001-08-01

    NASA is very interested in improving its ability to monitor and forecast the radiation levels that pose a health risk to space-walking astronauts as they construct the International Space Station and astronauts that will participate in long-term and deep-space missions. Human exploratory missions to the moon and Mars within the next quarter century, will expose crews to transient radiation from solar particle events which include high-energy galactic cosmic rays and high-energy protons. Because the radiation levels in space are high and solar activity is presently unpredictable, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. Today, numerous models have been developed and used to predict radiation exposure. Such a model is the Space Environment Information Systems (SPENVIS) modeling program, developed by the Belgian Institute for Space Aeronautics. SPENVIS, which has been assessed to be an excellent tool in characterizing the radiation environment for microelectronics and investigating orbital debris, is being evaluated for its usefulness with determining the dose and dose-equivalent for human exposure. Thus far, the calculations for dose-depth relations under varying shielding conditions have been in agreement with calculations done using HZETRN and PDOSE, which are well-known and widely used models for characterizing the environments for human exploratory missions. There is disagreement when assessing the impact of secondary radiation particles since SPENVIS does a crude estimation of the secondary radiation particles when calculating LET versus Flux. SPENVIS was used to model dose-depth relations for the blood-forming organs. Radiation sickness and cancer are life-threatening consequences resulting from radiation exposure. In space, exposure to radiation generally includes all of the critical organs. Biological and toxicological impacts have been included for discussion along with alternative risk mitigation

  10. Radiation transport modeling and assessment to better predict radiation exposure, dose, and toxicological effects to human organs on long duration space flights

    NASA Technical Reports Server (NTRS)

    Denkins, P.; Badhwar, G.; Obot, V.; Wilson, B.; Jejelewo, O.

    2001-01-01

    NASA is very interested in improving its ability to monitor and forecast the radiation levels that pose a health risk to space-walking astronauts as they construct the International Space Station and astronauts that will participate in long-term and deep-space missions. Human exploratory missions to the moon and Mars within the next quarter century, will expose crews to transient radiation from solar particle events which include high-energy galactic cosmic rays and high-energy protons. Because the radiation levels in space are high and solar activity is presently unpredictable, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. Today, numerous models have been developed and used to predict radiation exposure. Such a model is the Space Environment Information Systems (SPENVIS) modeling program, developed by the Belgian Institute for Space Aeronautics. SPENVIS, which has been assessed to be an excellent tool in characterizing the radiation environment for microelectronics and investigating orbital debris, is being evaluated for its usefulness with determining the dose and dose-equivalent for human exposure. Thus far. the calculations for dose-depth relations under varying shielding conditions have been in agreement with calculations done using HZETRN and PDOSE, which are well-known and widely used models for characterizing the environments for human exploratory missions. There is disagreement when assessing the impact of secondary radiation particles since SPENVIS does a crude estimation of the secondary radiation particles when calculating LET versus Flux. SPENVIS was used to model dose-depth relations for the blood-forming organs. Radiation sickness and cancer are life-threatening consequences resulting from radiation exposure. In space. exposure to radiation generally includes all of the critical organs. Biological and toxicological impacts have been included for discussion along with alternative risk mitigation

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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. Themore » 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.« less

  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. 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

  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. Assessment of the unattached fraction of indoor radon progeny and its contribution to dose: a pilot study in China.

    PubMed

    Guo, Qiuju; Zhang, Lei; Guo, Lu

    2012-12-01

    The unattached fraction of radon progeny (f(p)) is one of the most important factors for accurate evaluation of the effective dose from a unit of radon exposure, and it may vary greatly in different environments. For precise evaluation of the indoor radon exposure dose and the influence of unattached radon progeny, a pilot survey of f(p) in different environments was carried out in China with a portable and integrating monitor. The dose conversion factors for radon progeny are calculated with LUDEP(®) code, and the dose contributions from the unattached and the attached radon progenies were simultaneously evaluated based on the results of field measurements. The results show that even though the concentrations of radon progeny vary significantly among different indoor environments, the variations of f(p) seem relatively small (9.3-16.9%). The dose contribution from unattached radon progeny is generally larger (30.2-46.2%) in an indoor environment.

  16. [A quality assessment of notified occupational diseases submitted to the National Occupational Environment Service].

    PubMed

    Lander, F; Bach, B; Laursen, P

    1999-08-09

    The aim of this study was to assess the quality of a consecutive sample of occupational disease notifications submitted to the National Working Environment Service during 1994. The sample consisted of 860 notifications describing occupational diseases among persons working in companies situated in the county of Vejle. The data information e.g. company name and address, time of employment, harmful exposure and disease, were registered. An overall data quality assessment was performed including evaluation of the etiological connection between described occupational exposure and disease and potential preventive perspectives. The study showed that the notified informations in general were adequate, but doctors need to pay more attention to dose description of the harmful exposure. About 80% of the notifications presented an adequate connection between occupational exposure and disease. Only half of the notifications described preventable and recent (less than five years) harmful exposure. In conclusion, the Danish occupational disease notification system is in general of a high standard, and the National Working Environment Service could make more use of doctors' information provided in these notifications.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Clasie, Ben; Wroe, Andrew; Kooy, Hanne

    2010-01-15

    depth. 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.« less

  18. Quantities for assessing high photon doses to the body: a calculational approach.

    PubMed

    Eakins, Jonathan S; Ainsbury, Elizabeth A

    2018-06-01

    Tissue reactions are the most clinically significant consequences of high-dose exposures to ionising radiation. However, currently there is no universally recognized dose quantity that can be used to assess and report generalised risks to individuals following whole body exposures in the high-dose range. In this work, a number of potential dose quantities are presented and discussed, with mathematical modelling techniques employed to compare them and explore when their differences are most or least manifest. The results are interpreted to propose the average (D GRB ) of the absorbed doses to the stomach, small intestine, red bone marrow, and brain as the optimum quantity for informing assessments of risk. A second, maximally conservative dose quantity (D Max ) is also suggested, which places limits on any under-estimates resulting from the adoption of D GRB . The primary aim of this work is to spark debate, with further work required to refine the final choice of quantity or quantities most appropriate for the full range of different potential exposure scenarios.

  19. 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.

  20. 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

  1. 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. Copyright © 2015. Published by Elsevier B.V.

  2. Creating an interactive environment for pediatric assessment.

    PubMed

    de Armas Weber, D; Easley-Rosenberg, A

    2001-01-01

    An interactive assessment room (IAR) was conceived to explore the effect of a dynamic environment on the pediatric assessment process and subsequent individualized goal development. Selection of a central theme, creation of a multipurpose space, provision of multisensory experiences, maximization of environmental affordances, provision of effective motivators and opportunities for goal attainment, and facilitation of a transdisciplinary assessment were identified as integral to designing the IAR. A central farm theme was selected to create five task-oriented activity stations. The IAR offered a creative assessment environment for transdisciplinary, practice-based application of current motor development and behavioral models. In addition, the IAR facilitated exploratory play essential to promoting the client's optimal performance to arrive at the development of appropriate treatment goals.

  3. 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.

  4. Probabilistic assessment method of the non-monotonic dose-responses-Part I: Methodological approach.

    PubMed

    Chevillotte, Grégoire; Bernard, Audrey; Varret, Clémence; Ballet, Pascal; Bodin, Laurent; Roudot, Alain-Claude

    2017-08-01

    More and more studies aim to characterize non-monotonic dose response curves (NMDRCs). The greatest difficulty is to assess the statistical plausibility of NMDRCs from previously conducted dose response studies. This difficulty is linked to the fact that these studies present (i) few doses tested, (ii) a low sample size per dose, and (iii) the absence of any raw data. In this study, we propose a new methodological approach to probabilistically characterize NMDRCs. The methodology is composed of three main steps: (i) sampling from summary data to cover all the possibilities that may be presented by the responses measured by dose and to obtain a new raw database, (ii) statistical analysis of each sampled dose-response curve to characterize the slopes and their signs, and (iii) characterization of these dose-response curves according to the variation of the sign in the slope. This method allows characterizing all types of dose-response curves and can be applied both to continuous data and to discrete data. The aim of this study is to present the general principle of this probabilistic method which allows to assess the non-monotonic dose responses curves, and to present some results. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Range-Finding Risk Assessment of Inhalation Exposure to Nanodiamonds in a Laboratory Environment

    PubMed Central

    Koivisto, Antti J.; Palomäki, Jaana E.; Viitanen, Anna-Kaisa; Siivola, Kirsi M.; Koponen, Ismo K.; Yu, Mingzhou; Kanerva, Tomi S.; Norppa, Hannu; Alenius, Harri T.; Hussein, Tareq; Savolainen, Kai M.; Hämeri, Kaarle J.

    2014-01-01

    This study considers fundamental methods in occupational risk assessment of exposure to airborne engineered nanomaterials. We discuss characterization of particle emissions, exposure assessment, hazard assessment with in vitro studies, and risk range characterization using calculated inhaled doses and dose-response translated to humans from in vitro studies. Here, the methods were utilized to assess workers’ risk range of inhalation exposure to nanodiamonds (NDs) during handling and sieving of ND powder. NDs were agglomerated to over 500 nm particles, and mean exposure levels of different work tasks varied from 0.24 to 4.96 µg·m−3 (0.08 to 0.74 cm−3). In vitro-experiments suggested that ND exposure may cause a risk for activation of inflammatory cascade. However, risk range characterization based on in vitro dose-response was not performed because accurate assessment of delivered (settled) dose on the cells was not possible. Comparison of ND exposure with common pollutants revealed that ND exposure was below 5 μg·m−3, which is one of the proposed exposure limits for diesel particulate matter, and the workers’ calculated dose of NDs during the measurement day was 74 ng which corresponded to 0.02% of the modeled daily (24 h) dose of submicrometer urban air particles. PMID:24840353

  6. DOSE-RESPONSE ASSESSMENT FOR DEVELOPMENTAL TOXICITY III. STATISTICAL MODELS

    EPA Science Inventory

    Although quantitative modeling has been central to cancer risk assessment for years, the concept of do@e-response modeling for developmental effects is relatively new. he benchmark dose (BMD) approach has been proposed for use with developmental (as well as other noncancer) endpo...

  7. RADIATION PROTECTION CABIN FOR CATHETER-DIRECTED LIVER INTERVENTIONS: OPERATOR DOSE ASSESSMENT.

    PubMed

    Maleux, Geert; Bergans, Niki; Bosmans, Hilde; Bogaerts, Ria

    2016-09-01

    The number and complexity of interventional radiological procedures and in particular catheter-directed liver interventions have increased substantially. The current study investigates the reduction of personal doses when using a dedicated radiation protection cabin (RPC) for these procedures. Operator and assistant doses were assessed for 3 series of 20 chemoinfusion/chemoembolisation interventions, including an equal number of procedures with and without RPC. Whole body doses, finger doses and doses at the level of knees and eyes were evaluated with different types of TLD-100 Harshaw dosemeters. Dosemeters were also attached on the three walls of the RPC. The operator doses were significantly reduced by the RPC, but also without RPC, the doses appear to be limited as a result of thorough optimisation with existing radiation protection tools. The added value of the RPC should thus be determined by the outcome of balancing dose reduction and other aspects such as ergonomic benefits. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 completedmore » 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

  9. 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.

  10. 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

  11. Comparison, association, and risk assessment of phthalates in floor dust at different indoor environments in Delaware, USA.

    PubMed

    Bi, Xiaolong; Yuan, Shoujun; Pan, Xiaojun; Winstead, Cherese; Wang, Qiquan

    2015-01-01

    This study aimed to compare and assess phthalate contamination in various indoor environments. In this study, 44 floor dust samples from different indoor environments in Delaware, USA were collected and analyzed for 14 phthalates using gas chromatography-mass spectrometry. Phthalates were detected in all dust samples with the total concentration ranging from 84 to 7117 mg kg(-1). DEHP (di-2-ethylhexyl phthalate), BzBP (benzylbutyl phthalate), DBP (dibutyl phthalate), and DiBP (di-isobutyl phthalate) were both the most frequently and abundantly detected phthalates. The average concentration of total phthalates in dust from offices, student dorms, gyms, stores, and daycare centers was found to be significantly or insignificantly (P = 0.05) higher than that in dust from houses and apartments. Plastic flooring materials and the application of floor care chemical products were positively associated with total phthalate concentration in floor dust. Toxicological risk assessment indicated that an investigated daycare center in this study was the only indoor environment that may cause the intake amount of DEHP of infants, toddlers, and children via dust ingestion to exceed the reference dose established by the U.S. Environmental Protection Agency (USEPA). Regular monitoring on phthalate contamination in sensitive indoor environments is recommended.

  12. 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...

  13. 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.

  14. 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

  15. 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

  16. Dental radiography: tooth enamel EPR dose assessment from Rando phantom measurements

    NASA Astrophysics Data System (ADS)

    Aragno, D.; Fattibene, P.; Onori, S.; Aragno, D.; Fattibene, P.

    2000-09-01

    Electron paramagnetic resonance dosimetry of tooth enamel is now established as a suitable method for individual dose reconstruction following radiation accidents. The accuracy of the method is limited by some confounding factors, among which is the dose received due to medical x-ray irradiation. In the present paper the EPR response of tooth enamel to endoral examination was experimentally evaluated using an anthropomorphic phantom. The dose to enamel for a single exposure of a typical dental examination performed with a new x-ray generation unit working at 65 kVp gave rise to a CO2- signal of intensity similar to that induced by a dose of about 2 mGy of 60Co. EPR measurements were performed on the entire tooth with no attempt to separate buccal and lingual components. Also the dose to enamel for an orthopantomography exam was estimated. It was derived from TLD measurements as equivalent to 0.2 mGy of 60Co. In view of application to risk assessment analysis, in the present work the value for the ratio of the reference dose at the phantom surface measured with TLD to the dose at the tooth measured with EPR was determined.

  17. Monte Carlo assessment of the finger shallow dose from direct contact with a microcentrifuge tube containing common biotechnology isotopes in solution.

    PubMed

    Cutright, Dan; Medich, David; Ring, Joseph

    2012-04-01

    Eppendorf tubes often are used in biomedical research labs and contain radioactive tracers. Although the associated direct contact finger doses are typically small, it is suggested (and in line with the principle of ALARA) to handle these tubes from the cap of the tube. When containing radioactive material, handling a tube near the bottom conical section would unnecessarily increase the skin dose to the fingers. This investigation modeled a 2.0-mL Eppendorf tube containing various individual beta emitting isotopes commonly used in a biomedical research environment (i.e., (14)C, (3)H, (131)I, (32)P, and (35)S) to determine the skin dose when directly handling the tube at the cap end and when handling it at the bottom conical section. The primary goal of this paper is to assess how significantly this dose is altered by handling geometry. The skin dose to a single finger was calculated with Monte Carlo simulations using MCNP5 and determined at a depth of 0.007 cm(2) in water averaged over 10 cm as described in 10CFR20. Results show that the dose rate may vary by as much as a factor of 700 depending on handling geometry.

  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. 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

  20. Toxicogenomics and cancer risk assessment: a framework for key event analysis and dose-response assessment for nongenotoxic carcinogens.

    PubMed

    Bercu, Joel P; Jolly, Robert A; Flagella, Kelly M; Baker, Thomas K; Romero, Pedro; Stevens, James L

    2010-12-01

    In order to determine a threshold for nongenotoxic carcinogens, the traditional risk assessment approach has been to identify a mode of action (MOA) with a nonlinear dose-response. The dose-response for one or more key event(s) linked to the MOA for carcinogenicity allows a point of departure (POD) to be selected from the most sensitive effect dose or no-effect dose. However, this can be challenging because multiple MOAs and key events may exist for carcinogenicity and oftentimes extensive research is required to elucidate the MOA. In the present study, a microarray analysis was conducted to determine if a POD could be identified following short-term oral rat exposure with two nongenotoxic rodent carcinogens, fenofibrate and methapyrilene, using a benchmark dose analysis of genes aggregated in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and Gene Ontology (GO) biological processes, which likely encompass key event(s) for carcinogenicity. The gene expression response for fenofibrate given to rats for 2days was consistent with its MOA and known key events linked to PPARα activation. The temporal response from daily dosing with methapyrilene demonstrated biological complexity with waves of pathways/biological processes occurring over 1, 3, and 7days; nonetheless, the benchmark dose values were consistent over time. When comparing the dose-response of toxicogenomic data to tumorigenesis or precursor events, the toxicogenomics POD was slightly below any effect level. Our results suggest that toxicogenomic analysis using short-term studies can be used to identify a threshold for nongenotoxic carcinogens based on evaluation of potential key event(s) which then can be used within a risk assessment framework. Copyright © 2010 Elsevier Inc. All rights reserved.

  1. 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. © The Author 2015. Published by Oxford University Press on behalf of

  2. Assessing performance in complex team environments.

    PubMed

    Whitmore, Jeffrey N

    2005-07-01

    This paper provides a brief introduction to team performance assessment. It highlights some critical aspects leading to the successful measurement of team performance in realistic console operations; discusses the idea of process and outcome measures; presents two types of team data collection systems; and provides an example of team performance assessment. Team performance assessment is a complicated endeavor relative to assessing individual performance. Assessing team performance necessitates a clear understanding of each operator's task, both at the individual and team level, and requires planning for efficient data capture and analysis. Though team performance assessment requires considerable effort, the results can be very worthwhile. Most tasks performed in Command and Control environments are team tasks, and understanding this type of performance is becoming increasingly important to the evaluation of mission success and for overall system optimization.

  3. 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.

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

    PubMed

    Kopp, Felix K; Holzapfel, Konstantin; 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.

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

  6. 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.

  7. Assessment of intake and internal dose from iodine-131 for exposed workers handling radiopharmaceutical products.

    PubMed

    Bitar, A; Maghrabi, M; Doubal, A W

    2013-12-01

    Two methods for determination of internal dose due to (131)I intake during the preparation and handling of iodine radiopharmaceutical products have been compared. The first method was based on the measurement of (131)I in 24-hour urine samples while the second method was based on the measurement in vivo of (131)I in thyroid. The results have shown that urine analysis method can be used as a screening test but not for internal dose assessment of exposed workers. Thyroid monitoring method was found to be more reliable and accurate method for assessing internal dose from (131)I intake. In addition, the assessed internal dose showed that the annual internal effective dose for some workers was below 1 mSv with no risk classification, whereas the results of other group of workers were between 1 and 6 mSv with low risk classification. Only one worker reached 7.66 mSv with high risk classification; and this worker must be monitored individually. © 2013 Elsevier Ltd. All rights reserved.

  8. 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

  9. 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

    2017-09-01

    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.

  10. Human exposure and internal dose assessments of acrylamide in food.

    PubMed

    Dybing, E; Farmer, P B; Andersen, M; Fennell, T R; Lalljie, S P D; Müller, D J G; Olin, S; Petersen, B J; Schlatter, J; Scholz, G; Scimeca, J A; Slimani, N; Törnqvist, M; Tuijtelaars, S; Verger, P

    2005-03-01

    This review provides a framework contributing to the risk assessment of acrylamide in food. It is based on the outcome of the ILSI Europe FOSIE process, a risk assessment framework for chemicals in foods and adds to the overall framework by focusing especially on exposure assessment and internal dose assessment of acrylamide in food. Since the finding that acrylamide is formed in food during heat processing and preparation of food, much effort has been (and still is being) put into understanding its mechanism of formation, on developing analytical methods and determination of levels in food, and on evaluation of its toxicity and potential toxicity and potential human health consequences. Although several exposure estimations have been proposed, a systematic review of key information relevant to exposure assessment is currently lacking. The European and North American branches of the International Life Sciences Institute, ILSI, discussed critical aspects of exposure assessment, parameters influencing the outcome of exposure assessment and summarised data relevant to the acrylamide exposure assessment to aid the risk characterisation process. This paper reviews the data on acrylamide levels in food including its formation and analytical methods, the determination of human consumption patterns, dietary intake of the general population, estimation of maximum intake levels and identification of groups of potentially high intakes. Possible options and consequences of mitigation efforts to reduce exposure are discussed. Furthermore the association of intake levels with biomarkers of exposure and internal dose, considering aspects of bioavailability, is reviewed, and a physiologically-based toxicokinetic (PBTK) model is described that provides a good description of the kinetics of acrylamide in the rat. Each of the sections concludes with a summary of remaining gaps and uncertainties.

  11. 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.

  12. 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.

  13. 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

  14. Assessment of radiation doses in the UK from the Fukushima Daiichi Nuclear accident.

    PubMed

    Brown, J

    2014-06-01

    PHE has undertaken a simple dose assessment for members of the public living in the UK at the time of the accident at the Fukushima Daiichi nuclear power station in March 2011. PHE reported that there was no public health risk to the UK from the release of material from the accident in a statement made on 29 March 2013. This assessment confirms the initial estimate of the doses which were about the same as a person in the UK would receive in an hour from natural background.

  15. Nutrition Environment Food Pantry Assessment Tool (NEFPAT): Development and Evaluation.

    PubMed

    Nikolaus, Cassandra J; Laurent, Emily; Loehmer, Emily; An, Ruopeng; Khan, Naiman; McCaffrey, Jennifer

    2018-04-24

    To develop and evaluate a nutrition environment assessment tool to assess the consumer nutrition environment and use of recommended practices in food pantries. The Nutrition Environment Food Pantry Assessment Tool (NEFPAT) was developed based on a literature review and guidance from professionals working with food pantries. The tool was pilot-tested at 9 food pantries, an expert panel assessed content validity, and interrater reliability was evaluated by pairs in 3 pantries. After revisions, the NEFPAT was used in 27 pantries. Pilot tests indicated positive appraisal for the NEFPAT and recommendations were addressed. The NEFPAT's 6 objectives and the overall tool were rated as content valid by experts, with an average section rating of 3.85 ± 0.10. Intraclass correlation coefficients for interrater reliability were >0.90. The NEFPAT is content valid with high interrater reliability. It provides baseline data that could be valuable for interventions within the nutrition environment of food pantries. Published by Elsevier Inc.

  16. MOSFET assessment of radiation dose delivered to mice using the Small Animal Radiation Research Platform (SARRP).

    PubMed

    Ngwa, Wilfred; Korideck, Houari; Chin, Lee M; Makrigiorgos, G Mike; Berbeco, Ross I

    2011-12-01

    The Small Animal Radiation Research Platform (SARRP) is a novel isocentric irradiation system that enables state-of-the-art image-guided radiotherapy research to be performed with animal models. This paper reports the results obtained from investigations assessing the radiation dose delivered by the SARRP to different anatomical target volumes in mice. Surgically implanted metal oxide semiconductor field effect transistors (MOSFET) dosimeters were employed for the dose assessment. The results reveal differences between the calculated and measured dose of -3.5 to 0.5%, -5.2 to -0.7%, -3.9 to 0.5%, -5.9 to 2.5%, -5.5 to 0.5%, and -4.3 to 0% for the left kidney, liver, pancreas, prostate, left lung, and brain, respectively. Overall, the findings show less than 6% difference between the delivered and calculated dose, without tissue heterogeneity corrections. These results provide a useful assessment of the need for tissue heterogeneity corrections in SARRP dose calculations for clinically relevant tumor model sites.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rampado, Osvaldo, E-mail: orampado@cittadellasalute.to.it; Giglioli, Francesca Romana; Rossetti, Veronica

    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 inmore » 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

  18. Dose computation for therapeutic electron beams

    NASA Astrophysics Data System (ADS)

    Glegg, Martin Mackenzie

    three assesses the planning computers' ability to model electron beam penumbra at extended SSD. Calculations were compared with diode measurements in a water phantom. Further measurements assessed doses in the junction region produced by abutting an extended SSD electron field with opposed photon fields. Chapter four describes an investigation of the size and shape of the region enclosed by the 90% isodose line when produced by limiting the electron beam with square and elliptical apertures. The 90% isodose line was chosen because clinical treatments are often prescribed such that a given volume receives at least 90% dose. Calculated and measured dose distributions were compared in a plane normal to the beam central axis. Measurements were made by film dosimetry. While chapters two to four examine relative doses, chapter five assesses the accuracy of absolute dose (or output) calculations performed by the planning computers. Output variation with SSD and field size was examined. Two further situations already assessed for the distribution of relative dose were also considered: an obliquely incident field, and a field incident on an irregular surface. The accuracy of calculations was assessed against criteria stipulated by the International Commission on Radiation Units and Measurement (ICRU). The Varian Cadplan and Helax TMS treatment planning systems produce acceptable accuracy in the calculation of relative dose from therapeutic electron beams in most commonly encountered situations. When interpreting clinical dose distributions, however, knowledge of the limitations of the calculation algorithm employed by each system is required in order to identify the minority of situations where results are not accurate. The calculation of absolute dose is too inaccurate to implement in a clinical environment. (Abstract shortened by ProQuest.).

  19. Technical Note: SCUDA: A software platform for cumulative dose assessment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Park, Seyoun; McNutt, Todd; Quon, Harry

    Purpose: 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. Methods: SCUDA consists of deformable image registration (DIR), segmentation, dose computation modules, and a graphical user interface. It is connected to our imagemore » 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. Results: 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. Conclusions: The authors developed a unified software platform that

  20. Quantitative dose-response assessment of inhalation exposures to toxic air pollutants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jarabek, A.M.; Foureman, G.L.; Gift, J.S.

    1997-12-31

    Implementation of the 1990 Clean Air Act Amendments, including evaluation of residual risks. requires accurate human health risk estimates of both acute and chronic inhalation exposures to toxic air pollutants. The U.S. Environmental Protection Agency`s National Center for Environmental Assessment, Research Triangle Park, NC, has a research program that addresses several key issues for development of improved quantitative approaches for dose-response assessment. This paper describes three projects underway in the program. Project A describes a Bayesian approach that was developed to base dose-response estimates on combined data sets and that expresses these estimates as probability density functions. A categorical regressionmore » model has been developed that allows for the combination of all available acute data, with toxicity expressed as severity categories (e.g., mild, moderate, severe), and with both duration and concentration as governing factors. Project C encompasses two refinements to uncertainty factors (UFs) often applied to extrapolate dose-response estimates from laboratory animal data to human equivalent concentrations. Traditional UFs have been based on analyses of oral administration and may not be appropriate for extrapolation of inhalation exposures. Refinement of the UF applied to account for the use of subchronic rather than chronic data was based on an analysis of data from inhalation exposures (Project C-1). Mathematical modeling using the BMD approach was used to calculate the dose-response estimates for comparison between the subchronic and chronic data so that the estimates were not subject to dose-spacing or sample size variability. The second UF that was refined for extrapolation of inhalation data was the adjustment for the use of a LOAEL rather than a NOAEL (Project C-2).« less

  1. 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

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Khater, H; Dauffy, L; Sitaraman, 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 withmore » 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.« less

  3. Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters

    PubMed Central

    Qiu, Bo; Liang, Jian; Xie, Weihao; Deng, Xiaowu; Qi, Zhenyu

    2017-01-01

    Objective: To assess the breast dose during a routine thoracic cone-beam CT (CBCT) check with the efforts to explore the possible dose reduction strategy. Materials and Methods: Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were used to measure breast surface doses during a thorax kV CBCT scan in an anthropomorphic phantom. Breast doses for different scanning protocols and breast sizes were compared. Dose reduction was attempted by using partial arc CBCT scan with bowtie filter. The impact of this dose reduction strategy on image registration accuracy was investigated. Results: The average breast surface doses were 20.02 mGy and 11.65 mGy for thoracic CBCT without filtration and with filtration, respectively. This indicates a dose reduction of 41.8% by use of bowtie filter. It was found 220° partial arc scanning significantly reduced the dose to contralateral breast (44.4% lower than ipsilateral breast), while the image registration accuracy was not compromised. Conclusions: Breast dose reduction can be achieved by using ipsilateral 220° partial arc scan with bowtie filter. This strategy also provides sufficient image quality for thorax image registration in daily patient positioning verification. PMID:28423624

  4. Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters.

    PubMed

    Sun, Wenzhao; Wang, Bin; Qiu, Bo; Liang, Jian; Xie, Weihao; Deng, Xiaowu; Qi, Zhenyu

    2017-03-21

    To assess the breast dose during a routine thoracic cone-beam CT (CBCT) check with the efforts to explore the possible dose reduction strategy. Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were used to measure breast surface doses during a thorax kV CBCT scan in an anthropomorphic phantom. Breast doses for different scanning protocols and breast sizes were compared. Dose reduction was attempted by using partial arc CBCT scan with bowtie filter. The impact of this dose reduction strategy on image registration accuracy was investigated. The average breast surface doses were 20.02 mGy and 11.65 mGy for thoracic CBCT without filtration and with filtration, respectively. This indicates a dose reduction of 41.8% by use of bowtie filter. It was found 220° partial arc scanning significantly reduced the dose to contralateral breast (44.4% lower than ipsilateral breast), while the image registration accuracy was not compromised. Breast dose reduction can be achieved by using ipsilateral 220° partial arc scan with bowtie filter. This strategy also provides sufficient image quality for thorax image registration in daily patient positioning verification.

  5. A Characteristic Dose Model for Historical Internal Dose Reconstruction in the Framework of the IAEC Compensation Programme.

    PubMed

    Kravchik, T; Abraham, A; Israeli, M; Yahel, E

    2017-04-25

    A model was developed at the Nuclear Research Centre Negev (NRCN) to assess historical doses from internal exposures by a relatively fast and simple procedure. These assessments are needed in the framework of a compensation programme for the Israeli Atomic Energy Commission (IAEC) workers, which were diagnosed for cancer diseases. This compensation programme was recently recommended by a public committee to avoid lengthy court procedures. The developed model is based on the recorded doses from external exposures of all the workers at the NRCN, who were divided into groups representing their different working environments. Each group of workers was characterised by three parameters: working period, working areas and occupation. The model uses several conservative assumptions in order to calculate the doses to various body organs in certain years, which are relevant to the calculation of the probability of causation (POC). The POC value serves as a main parameter in the compensation programme. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. 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

  7. 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...

  8. Developing Urban Environment Indicators for Neighborhood Sustainability Assessment in Tripoli-Libya

    NASA Astrophysics Data System (ADS)

    Elgadi, Ahmed. A.; Hakim Ismail, Lokman; Abass, Fatma; Ali, Abdelmuniem

    2016-11-01

    Sustainability assessment frameworks are becoming increasingly important to assist in the transition towards a sustainable urban environment. The urban environment is an effective system and requires regular monitoring and evaluation through a set of relevant indicators. The indicator provides information about the state of the environment through the production value of quantity. The indicator creates sustainability assessment requests to be considered on all spatial scales to specify efficient information of urban environment sustainability in Tripoli-Libya. Detailed data is necessary to assess environmental modification in the urban environment on a local scale and ease the transfer of this information to national and global stages. This paper proposes a set of key indicators to monitor urban environmental sustainability developments of Libyan residential neighborhoods. The proposed environmental indicator framework measures the sustainability performance of an urban environment through 13 sub-categories consisting of 21 indicators. This paper also explains the theoretical foundations for the selection of all indicators with reference to previous studies.

  9. Technical assessment of a cone-beam CT scanner for otolaryngology imaging: image quality, dose, and technique protocols.

    PubMed

    Xu, J; Reh, D D; Carey, J P; Mahesh, M; Siewerdsen, J H

    2012-08-01

    As cone-beam CT (CBCT) systems dedicated to various imaging specialties proliferate, technical assessment grounded in imaging physics is important to ensuring that image quality and radiation dose are quantified, understood, and justified. This paper involves technical assessment of a new CBCT scanner (CS 9300, Carestream Health, Rochester, NY) dedicated to imaging of the ear and sinuses for applications in otolaryngology-head and neck surgery (OHNS). The results guided evaluation of technique protocols to minimize radiation dose in a manner sufficient for OHNS imaging tasks. The technical assessment focused on the imaging performance and radiation dose for each of seven technique protocols recommended by the manufacturer: three sinus protocols and four ear (temporal bone) protocols. Absolute dose was measured using techniques adapted from AAPM Task Group Report No. 111, involving three stacked 16 cm diameter acrylic cylinders (CTDI phantoms) and a 0.6 cm(3) Farmer ionization chamber to measure central and peripheral dose. The central dose (D(o)) was also measured as a function of longitudinal position (z) within and beyond the primary radiation field to assess, for example, out-of-field dose to the neck. Signal-difference-to-noise ratio (SDNR) and Hounsfield unit (HU) accuracy were assessed in a commercially available quality assurance phantom (CATPHAN module CTP404, The Phantom Laboratory, Greenwich, NY) and a custom phantom with soft-tissue-simulating plastic inserts (Gammex RMI, Madison, WI). Spatial resolution was assessed both qualitatively (a line-pair pattern, CATPHAN module CTP528) and quantitatively (modulation transfer function, MTF, measured with a wire phantom). Imaging performance pertinent to various OHNS imaging tasks was qualitatively assessed using an anthropomorphic phantom as evaluated by two experienced OHNS specialists. The technical assessment motivated a variety of modifications to the manufacturer-specified protocols to provide reduced

  10. ESTIMATING CONTAMINANT DOSE FOR INTERMITTENT DERMAL CONTACT: MODEL DEVELOPMENT, TESTING, AND APPLICATION

    EPA Science Inventory

    Assessments of aggregate exposure to pesticides and other surface contamination in residential environments are often driven by assumptions about dermal contacts. Accurately predicting cumulative doses from realistic skin contact scenarios requires characterization of exposure sc...

  11. Assessment of organ-specific neutron equivalent doses in proton therapy using computational whole-body age-dependent voxel phantoms

    NASA Astrophysics Data System (ADS)

    Zacharatou Jarlskog, Christina; Lee, Choonik; Bolch, Wesley E.; Xu, X. George; Paganetti, Harald

    2008-02-01

    Proton beams used for radiotherapy will produce neutrons when interacting with matter. The purpose of this study was to quantify the equivalent dose to tissue due to secondary neutrons in pediatric and adult patients treated by proton therapy for brain lesions. Assessment of the equivalent dose to organs away from the target requires whole-body geometrical information. Furthermore, because the patient geometry depends on age at exposure, age-dependent representations are also needed. We implemented age-dependent phantoms into our proton Monte Carlo dose calculation environment. We considered eight typical radiation fields, two of which had been previously used to treat pediatric patients. The other six fields were additionally considered to allow a systematic study of equivalent doses as a function of field parameters. For all phantoms and all fields, we simulated organ-specific equivalent neutron doses and analyzed for each organ (1) the equivalent dose due to neutrons as a function of distance to the target; (2) the equivalent dose due to neutrons as a function of patient age; (3) the equivalent dose due to neutrons as a function of field parameters; and (4) the ratio of contributions to secondary dose from the treatment head versus the contribution from the patient's body tissues. This work reports organ-specific equivalent neutron doses for up to 48 organs in a patient. We demonstrate quantitatively how organ equivalent doses for adult and pediatric patients vary as a function of patient's age, organ and field parameters. Neutron doses increase with increasing range and modulation width but decrease with field size (as defined by the aperture). We analyzed the ratio of neutron dose contributions from the patient and from the treatment head, and found that neutron-equivalent doses fall off rapidly as a function of distance from the target, in agreement with experimental data. It appears that for the fields used in this study, the neutron dose lateral to the

  12. 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. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  13. Reference dose (RfD): description and use in health risk assessments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Barnes, D.G.; Dourson, M.

    1988-12-01

    For many years the concept of the acceptable daily intake has served the toxicological and regulatory fields quite well. However, as approaches to assessing the health significance of exposures to noncarcinogenic substances receive greater scrutiny, some difficulties with this traditional approach have become more apparent. Consequently, the concept of the reference dose is introduced in order to avoid use of prejudicial terms (e.g., safety and acceptable), to promote greater consistency in the assessment of noncarcinogenic chemicals, and to maintain the functional separation between risk assessment and risk management.

  14. 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...

  15. Eye lens radiation exposure to interventional cardiologists: a retrospective assessment of cumulative doses.

    PubMed

    Jacob, Sophie; Donadille, Laurent; Maccia, Carlo; Bar, Olivier; Boveda, Serge; Laurier, Dominique; Bernier, Marie-Odile

    2013-03-01

    Radiation dose to the eye lens is a crucial issue for interventional cardiologists (ICs) who are exposed during the procedures they perform. This paper presents a retrospective assessment of the cumulative eye lens doses of ICs enrolled in the O'CLOC study for Occupational Cataracts and Lens Opacities in interventional Cardiology. Information on the workload in the catheterisation laboratory, radiation protection equipment, eye lens dose per procedure and dose reduction factors associated with eye-protective equipment were considered. For the 129 ICs at an average age of 51 who had worked for an average period of 22 years, the estimated cumulative eye lens dose ranged from 25 mSv to more than 1600 mSv; the mean ± SD was 423 ± 359 mSv. After several years of practice, without eye protection, ICs may exceed the new ICRP lifetime eye dose threshold of 500 mSv and be at high risk of developing early radiation-induced cataracts. Radiation protection equipment can reduce these doses and should be used routinely.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 andmore » 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)« less

  18. 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.

  19. A METHOD TO IMPROVE DOSE ASSESSMENT BY RECONSTRUCTION OF THE COMPLETE ISOTOPES INVENTORY.

    PubMed

    Bonin, Alice; Tsilanizara, Aimé

    2017-06-01

    Radiation shielding assessments may underestimate the expected dose if some isotopes at trace level are not considered in the isotopes inventory of the shielded radioactive materials. Indeed, information about traces is not often available. Nevertheless, the activation of some minor isotopic traces may significantly contribute to the dose build-up. This paper presents a new method (Isotopes Inventory Reconstruction-IIR) estimating the concentration of the minor isotopes in the irradiated material at the beginning of the cooling period. The method requires the solution of the inverse problem describing the irradiated material's decay. In a mixture of an irradiated uranium-plutonium oxide shielded by a set-up made of stainless-steel, porous polyethylene plaster and lead methyl methacrylate, the comparison between different methods proves that the IIR-method allows better assessment of the dose than other approximate methods. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Application of ISO standard 27048: dose assessment for the monitoring of workers for internal radiation exposure.

    PubMed

    Henrichs, K

    2011-03-01

    Besides ongoing developments in the dosimetry of incorporated radionuclides, there are various efforts to improve the monitoring of workers for potential or real intakes of radionuclides. The disillusioning experience with numerous intercomparison projects identified substantial differences between national regulations, concepts, applied programmes and methods, and dose assessment procedures. Measured activities were not directly comparable because of significant differences between measuring frequencies and methods, but also results of case studies for dose assessments revealed differences of orders of magnitude. Besides the general common interest in reliable monitoring results, at least the cross-border activities of workers (e.g. nuclear power plant services) require consistent approaches and comparable results. The International Standardization Organization therefore initiated projects to standardise programmes for the monitoring of workers, the requirements for measuring laboratories and the processes for the quantitative evaluation of monitoring results in terms of internal assessed doses. The strength of the concepts applied by the international working group consists in a unified approach defining the requirements, databases and processes. This paper is intended to give a short introduction into the standardization project followed by a more detailed description of the dose assessment standard, which will be published in the very near future.

  1. 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

  2. Application of the ELDO approach to assess cumulative eye lens doses for interventional cardiologists.

    PubMed

    Farah, J; Struelens, L; Auvinen, A; Jacob, S; Koukorava, C; Schnelzer, M; Vanhavere, F; Clairand, I

    2015-04-01

    In preparation of a large European epidemiological study on the relation between eye lens dose and the occurrence of lens opacities, the European ELDO project focused on the development of practical methods to estimate retrospectively cumulative eye lens dose for interventional medical professionals exposed to radiation. The present paper applies one of the ELDO approaches, correlating eye lens dose to whole-body doses, to assess cumulative eye lens dose for 14 different Finnish interventional cardiologists for whom annual whole-body dose records were available for their entire working period. The estimated cumulative left and right eye lens dose ranged from 8 to 264 mSv and 6 to 225 mSv, respectively. In addition, calculations showed annual eye lens doses sometimes exceeding the new ICRP annual limit of 20 mSv. The work also highlights the large uncertainties associated with the application of such an approach proving the need for dedicated dosimetry systems in the routine monitoring of the eye lens dose. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Measuring the food service environment: development and implementation of assessment tools.

    PubMed

    Minaker, Leia M; Raine, Kim D; Cash, Sean B

    2009-01-01

    The food environment is increasingly being implicated in the obesity epidemic, though few reported measures of it exist. In order to assess the impact of the food environment on food intake, valid measures must be developed and tested. The current study describes the development of a food service environment assessment tool and its implementation in a community setting. A descriptive study with mixed qualitative and quantitative methods at a large, North American university campus was undertaken. Measures were developed on the basis of a conceptual model of nutrition environments. Measures of community nutrition environment were the number, type and hours of operation of each food service outlet on campus. Measures of consumer nutrition environment were food availability, food affordability, food promotion and nutrition information availability. Seventy-five food service outlets within the geographic boundaries were assessed. Assessment tools could be implemented in a reasonable amount of time and showed good face and content validity. The food environments were described and measures were grouped so that food service outlet types could be compared in terms of purchasing convenience, cost/value, healthy food promotion and health. Food service outlet types that scored higher in purchasing convenience and cost/value tended to score lower in healthy food promotion and health. This study adds evidence that food service outlet types that are convenient to consumers and supply high value (in terms of calories per dollar) tend to be less health-promoting. Results from this study also suggest the possibility of characterizing the food environment according to the type of food service outlet observed.

  4. Dose tracking and dose auditing in a comprehensive computed tomography dose-reduction program.

    PubMed

    Duong, Phuong-Anh; Little, Brent P

    2014-08-01

    Implementation of a comprehensive computed tomography (CT) radiation dose-reduction program is a complex undertaking, requiring an assessment of baseline doses, an understanding of dose-saving techniques, and an ongoing appraisal of results. We describe the role of dose tracking in planning and executing a dose-reduction program and discuss the use of the American College of Radiology CT Dose Index Registry at our institution. We review the basics of dose-related CT scan parameters, the components of the dose report, and the dose-reduction techniques, showing how an understanding of each technique is important in effective auditing of "outlier" doses identified by dose tracking. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. 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…

  6. An Assessment of a Mixed Reality Environment: Toward an Ethnomethodological Approach

    ERIC Educational Resources Information Center

    Dugdale, Julie; Pallamin, Nico; Pavard, Bernard

    2006-01-01

    Training firefighters is a difficult process in which emotions and nonverbal behaviors play an important role. The authors have developed a mixed reality environment for training a small group of firefighters, which takes into account these aspects. The assessment of the environment was made up of three phases: assessing the virtual agents to…

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 providedmore » 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.« less

  8. Pulmonary disease in cystic fibrosis: assessment with chest CT at chest radiography dose levels.

    PubMed

    Ernst, Caroline W; Basten, Ines A; Ilsen, Bart; Buls, Nico; Van Gompel, Gert; De Wachter, Elke; Nieboer, Koenraad H; Verhelle, Filip; Malfroot, Anne; Coomans, Danny; De Maeseneer, Michel; de Mey, Johan

    2014-11-01

    To investigate a computed tomographic (CT) protocol with iterative reconstruction at conventional radiography dose levels for the assessment of structural lung abnormalities in patients with cystic fibrosis ( CF cystic fibrosis ). In this institutional review board-approved study, 38 patients with CF cystic fibrosis (age range, 6-58 years; 21 patients <18 years and 17 patients >18 years) underwent investigative CT (at minimal exposure settings combined with iterative reconstruction) as a replacement of yearly follow-up posteroanterior chest radiography. Verbal informed consent was obtained from all patients or their parents. CT images were randomized and rated independently by two radiologists with use of the Bhalla scoring system. In addition, mosaic perfusion was evaluated. As reference, the previous available conventional chest CT scan was used. Differences in Bhalla scores were assessed with the χ(2) test and intraclass correlation coefficients ( ICC intraclass correlation coefficient s). Radiation doses for CT and radiography were assessed for adults (>18 years) and children (<18 years) separately by using technical dose descriptors and estimated effective dose. Differences in dose were assessed with the Mann-Whitney U test. The median effective dose for the investigative protocol was 0.04 mSv (95% confidence interval [ CI confidence interval ]: 0.034 mSv, 0.10 mSv) for children and 0.05 mSv (95% CI confidence interval : 0.04 mSv, 0.08 mSv) for adults. These doses were much lower than those with conventional CT (median: 0.52 mSv [95% CI confidence interval : 0.31 mSv, 3.90 mSv] for children and 1.12 mSv [95% CI confidence interval : 0.57 mSv, 3.15 mSv] for adults) and of the same order of magnitude as those for conventional radiography (median: 0.012 mSv [95% CI confidence interval : 0.006 mSv, 0.022 mSv] for children and 0.012 mSv [95% CI confidence interval : 0.005 mSv, 0.031 mSv] for adults). All images were rated at least as diagnostically acceptable

  9. Assessment of dose and risk to the body following conventional and spiral computed tomography.

    PubMed

    Chang, L L; Chen, F D; Chang, P S; Liu, C C; Lien, H L

    1995-04-01

    Computed tomography (CT) is one of the most frequently used examination procedures in diagnostic radiology and the dose given to the patients is higher than in general radiographic procedures. In this study LiF chip thermoluminescent dosimeters (TLD-100) were placed in each relative organ or tissue position, including head, chest and abdomen, in a Rando phantom. CT was performed using both conventional and spiral modes, and effective dose and effective dose equivalent were assessed for each organ or tissue scanned. The TLD reader used in this experiment was controlled at a nitrogen flow rate of 450 ml/min, preheat time of 14 seconds, reading time of 16 seconds and annealing time of 16 seconds. This CT scanner can be used to perform both conventional and spiral tomography. Operating conditions for spiral tomography were 120 kV, 80 mA for scout film, and 120 kV, 200 mA, 1 sec/slice for each scanning. However, for conventional tomography, the operating conditions were 120 kV, 80 mA for scout film and 120 kV, 160 mA, 1.5 sec/slice for each scanning. These operating conditions are satisfactory to most clinical applications, and therefore were adopted for the present studies. Results showed that, in both effective dose and effective dose and effective dose equivalent, conventional tomography was higher than spiral tomography. The average effective doses for each part were measured to be 1.89 and 4.95 mSv for the head, 30.01 and 40.65 mSv for the chest, and 12.85 and 19.62 mSv for the abdomen of spiral and conventional CT, respectively. Higher carcinogenic risk was assessed in organs such as liver, lung, stomach and bone marrow, other organs had a relatively lower incidence of risk. The main purpose of this study was to obtain distribution values of effective dose and effective dose equivalent, and to know the probability of carcinogenic effect upon each organ or tissue after CT scanning. Results showed the average effective dose for spiral CT to be less than conventional

  10. 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…

  11. Low-Dose Carcinogenicity Studies

    EPA Science Inventory

    One of the major deficiencies of cancer risk assessments is the lack of low-dose carcinogenicity data. Most assessments require extrapolation from high to low doses, which is subject to various uncertainties. Only 4 low-dose carcinogenicity studies and 5 low-dose biomarker/pre-n...

  12. 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…

  13. Review and comparison between the Wells-Riley and dose-response approaches to risk assessment of infectious respiratory diseases.

    PubMed

    Sze To, G N; Chao, C Y H

    2010-02-01

    Infection risk assessment is very useful in understanding the transmission dynamics of infectious diseases and in predicting the risk of these diseases to the public. Quantitative infection risk assessment can provide quantitative analysis of disease transmission and the effectiveness of infection control measures. The Wells-Riley model has been extensively used for quantitative infection risk assessment of respiratory infectious diseases in indoor premises. Some newer studies have also proposed the use of dose-response models for such purpose. This study reviews and compares these two approaches to infection risk assessment of respiratory infectious diseases. The Wells-Riley model allows quick assessment and does not require interspecies extrapolation of infectivity. Dose-response models can consider other disease transmission routes in addition to airborne route and can calculate the infectious source strength of an outbreak in terms of the quantity of the pathogen rather than a hypothetical unit. Spatial distribution of airborne pathogens is one of the most important factors in infection risk assessment of respiratory disease. Respiratory deposition of aerosol induces heterogeneous infectivity of intake pathogens and randomness on the intake dose, which are not being well accounted for in current risk models. Some suggestions for further development of the risk assessment models are proposed. This review article summarizes the strengths and limitations of the Wells-Riley and the dose-response models for risk assessment of respiratory diseases. Even with many efforts by various investigators to develop and modify the risk assessment models, some limitations still persist. This review serves as a reference for further development of infection risk assessment models of respiratory diseases. The Wells-Riley model and dose-response model offer specific advantages. Risk assessors can select the approach that is suitable to their particular conditions to perform risk

  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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Streitparth, Florian; Pech, Maciej; Boehmig, Michael

    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 datamore » 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.« less

  15. [Research progress and development trend of quantitative assessment techniques for urban thermal environment.

    PubMed

    Sun, Tie Gang; Xiao, Rong Bo; Cai, Yun Nan; Wang, Yao Wu; Wu, Chang Guang

    2016-08-01

    Quantitative assessment of urban thermal environment has become a focus for urban climate and environmental science since the concept of urban heat island has been proposed. With the continual development of space information and computer simulation technology, substantial progresses have been made on quantitative assessment techniques and methods of urban thermal environment. The quantitative assessment techniques have been developed to dynamics simulation and forecast of thermal environment at various scales based on statistical analysis of thermal environment on urban-scale using the historical data of weather stations. This study reviewed the development progress of ground meteorological observation, thermal infrared remote sensing and numerical simulation. Moreover, the potential advantages and disadvantages, applicability and the development trends of these techniques were also summarized, aiming to add fundamental knowledge of understanding the urban thermal environment assessment and optimization.

  16. 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.

  17. 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.

  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. An organ-based approach to dose calculation in the assessment of dose-dependent biological effects of ionising radiation in Arabidopsis thaliana.

    PubMed

    Biermans, Geert; Horemans, Nele; Vanhoudt, Nathalie; Vandenhove, Hildegarde; Saenen, Eline; Van Hees, May; Wannijn, Jean; Vives i Batlle, Jordi; Cuypers, Ann

    2014-07-01

    There is a need for a better understanding of biological effects of radiation exposure in non-human biota. Correct description of these effects requires a more detailed model of dosimetry than that available in current risk assessment tools, particularly for plants. In this paper, we propose a simple model for dose calculations in roots and shoots of Arabidopsis thaliana seedlings exposed to radionuclides in a hydroponic exposure setup. This model is used to compare absorbed doses for three radionuclides, (241)Am (α-radiation), (90)Sr (β-radiation) and (133)Ba (γ radiation). Using established dosimetric calculation methods, dose conversion coefficient values were determined for each organ separately based on uptake data from the different plant organs. These calculations were then compared to the DCC values obtained with the ERICA tool under equivalent geometry assumptions. When comparing with our new method, the ERICA tool appears to overestimate internal doses and underestimate external doses in the roots for all three radionuclides, though each to a different extent. These observations might help to refine dose-response relationships. The DCC values for (90)Sr in roots are shown to deviate the most. A dose-effect curve for (90)Sr β-radiation has been established on biomass and photosynthesis endpoints, but no significant dose-dependent effects are observed. This indicates the need for use of endpoints at the molecular and physiological scale. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Assessment of low-dose cisplatin as a model of nausea and emesis in beagle dogs, potential for repeated administration.

    PubMed

    Kenward, Hannah; Pelligand, Ludovic; Elliott, Jonathan

    2014-08-01

    Cisplatin is a highly emetogenic cancer chemotherapy agent, which is often used to induce nausea and emesis in animal models. The cytotoxic properties of cisplatin also cause adverse events that negatively impact on animal welfare preventing repeated administration of cisplatin. In this study, we assessed whether a low (subclinical) dose of cisplatin could be utilized as a model of nausea and emesis in the dog while decreasing the severity of adverse events to allow repeated administration. The emetic, nausea-like behavior and potential biomarker response to both the clinical dose (70 mg/m2) and low dose (15 mg/m2) of cisplatin was assessed. Plasma creatinine concentrations and granulocyte counts were used to assess adverse effects on the kidneys and bone marrow, respectively. Nausea-like behavior and emesis was induced by both doses of cisplatin, but the latency to onset was greater in the low-dose group. No significant change in plasma creatinine was detected for either dose groups. Granulocytes were significantly reduced compared with baseline (P = 0.000) following the clinical, but not the low-dose cisplatin group. Tolerability of repeated administration was assessed with 4 administrations of an 18 mg/m2 dose cisplatin. Plasma creatinine did not change significantly. Cumulative effects on the granulocytes occurred, they were significantly decreased (P = 0.03) from baseline at 3 weeks following cisplatin for the 4th administration only. Our results suggest that subclinical doses (15 and 18 mg/m2) of cisplatin induce nausea-like behavior and emesis but have reduced adverse effects compared with the clinical dose allowing for repeated administration in crossover studies.

  1. Assessing a Faculty Development Program in a Changing Environment

    ERIC Educational Resources Information Center

    Lockhart, Marilyn S.; Stoop, Chatanika

    2018-01-01

    The environment in which faculty development centers operate has changed significantly. As a result, centers are asked to play a more important role in contributing to institutional strategic initiatives, assess outcomes of programs, and enhance faculty scholarship success. In the past, assessments have focused on attendance and satisfaction…

  2. 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

  3. Natural Environment Language Assessment and Intervention with Severely Impaired Preschoolers.

    ERIC Educational Resources Information Center

    Halle, James W.; And Others

    1984-01-01

    The paper presents a rationale for assessing and intervening with severely impaired preschoolers in the natural environment, identifies three prerequisites for language training (content and motivation, reinforcing social and physical environment, and a communicative repertoire), and examines two levels of intervention. (CL)

  4. 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...

  5. Feasibility study for distributed dose monitoring in ionizing radiation environments with standard and custom-made optical fibers

    NASA Astrophysics Data System (ADS)

    Van Uffelen, Marco; Berghmans, Francis; Brichard, Benoit; Borgermans, Paul; Decréton, Marc C.

    2002-09-01

    Optical fibers stimulate much interest since many years for their potential use in various nuclear environments, both for radiation tolerant and EMI-free data communication as well as for distributed sensing. Besides monitoring temperature and stress, measuring ionizing doses with optical fibers is particularly essential in applications such as long-term nuclear waste disposal monitoring, and for real-time aging monitoring of power and signal cables installed inside a reactor containment building. Two distinct options exist to perform optical fiber dosimetry. First, find an accurate model for a restricted application field that accounts for all the parameters that influence the radiation response of a standard fiber, or second, develop a dedicated fiber with a response that will solely depend on the deposited energy. Using various models presented in literature, we evaluate both standard commercially available and custom-made optical fibers under gamma radiation, particularly for distributed dosimetry applications with an optical time domain reflectometer (OTDR). We therefore present the radiation induced attenuation at near-infrared telecom wavelengths up to MGy total dose levels, with dose rates ranging from about 1 Gy/h up to 1 kGy/h, whereas temperature was raised step-wise from 25 °C to 85 °C. Our results allow to determine and compare the practical limitations of distributed dose measurements with both fiber types in terms of temperature sensitivity, dose estimation accuracy and spatial resolution.

  6. Assessing and Monitoring Student Progress in an E-Learning Personnel Preparation Environment.

    ERIC Educational Resources Information Center

    Meyen, Edward L.; Aust, Ronald J.; Bui, Yvonne N.; Isaacson, Robert

    2002-01-01

    Discussion of e-learning in special education personnel preparation focuses on student assessment in e-learning environments. It includes a review of the literature, lessons learned by the authors from assessing student performance in e-learning environments, a literature perspective on electronic portfolios in monitoring student progress, and the…

  7. Challenges in assessing food environments in northern and remote communities in Canada.

    PubMed

    Skinner, Kelly; Burnett, Kristin; Williams, Patricia; Martin, Debbie; Stothart, Christopher; LeBlanc, Joseph; Veeraraghavan, Gigi; Sheedy, Amanda

    2016-06-09

    Effective tools for retail food environments in northern and remote communities are lacking. This paper examines the challenges of conducting food environment assessments in northern and remote communities in Canada encountered during our experience with a food costing project. One of the goals of the Paying for Nutrition in the North project is to develop guidelines to improve current food costing tools for northern Canada. Paying for Nutrition illustrates the complex context of measuring food environments in northern and remote communities. Through the development of a food costing methodology guide to assess northern food environments, several contextual issues emerged, including retail store oligopolies in communities; the importance of assessing food quality; informal social food economies; and the challenge of costing the acquisition and consumption of land- and water-based foods. Food environment measures designed for northern and remote communities need to reflect the geographic context in which they are being employed and must include input from local residents.

  8. 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…

  9. The susceptibility of TaO x-based memristors to high dose rate ionizing radiation and total ionizing dose

    DOE PAGES

    McLain, Michael Lee; Sheridan, Timothy J.; Hjalmarson, Harold Paul; ...

    2014-11-11

    This paper investigates the effects of high dose rate ionizing radiation and total ionizing dose (TID) on tantalum oxide (TaO x) memristors. Transient data were obtained during the pulsed exposures for dose rates ranging from approximately 5.0 ×10 7 rad(Si)/s to 4.7 ×10 8 rad(Si)/s and for pulse widths ranging from 50 ns to 50 μs. The cumulative dose in these tests did not appear to impact the observed dose rate response. Static dose rate upset tests were also performed at a dose rate of ~3.0 ×10 8 rad(Si)/s. This is the first dose rate study on any type ofmore » memristive memory technology. In addition to assessing the tolerance of TaO x memristors to high dose rate ionizing radiation, we also evaluated their susceptibility to TID. The data indicate that it is possible for the devices to switch from a high resistance off-state to a low resistance on-state in both dose rate and TID environments. The observed radiation-induced switching is dependent on the irradiation conditions and bias configuration. Furthermore, the dose rate or ionizing dose level at which a device switches resistance states varies from device to device; the enhanced susceptibility observed in some devices is still under investigation. As a result, numerical simulations are used to qualitatively capture the observed transient radiation response and provide insight into the physics of the induced current/voltages.« less

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

    PubMed

    Dverstorp, Björn; Xu, Shulan

    2017-11-01

    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. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Radiation Dose-Response Relationships and Risk Assessment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Strom, Daniel J.

    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 alsomore » 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

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schuemann, Jan, E-mail: jschuemann@mgh.harvard.edu; Giantsoudi, Drosoula; Grassberger, Clemens

    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%more » 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.« less

  13. The University Environment: A Comprehensive Assessment of Health-Related Advertisements

    ERIC Educational Resources Information Center

    Szymona, Katie; Quick, Virginia; Olfert, Melissa; Shelnutt, Karla; Kattlemann, Kendra K.; Brown-Esters, Onikia; Colby, Sarah E.; Beaudoin, Christina; Lubniewski, Jocelyn; Maia, Angelina Moore; Horacek, Tanya; Byrd-Bredbenner, Carol

    2012-01-01

    Purpose: Little is known about health-related advertising on university environments. Given the power of advertising and its potential effect on health behaviors, the purpose of this paper is to assess the health-related advertisement environment and policies on university campuses. Design/methodology/approach: In total, ten geographically and…

  14. 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. Copyright © 2015 by the American Occupational Therapy Association, Inc.

  15. Manned Mars mission radiation environment and radiobiology

    NASA Technical Reports Server (NTRS)

    Nachtwey, D. S.

    1986-01-01

    Potential radiation hazards to crew members on manned Mars missions are discussed. It deals briefly with radiation sources and environments likely to be encountered during various phases of such missions, providing quantitative estimates of these environments. Also provided are quantitative data and discussions on the implications of such radiation on the human body. Various sorts of protective measures are suggested. Recent re-evaluation of allowable dose limits by the National Council of Radiation Protection is discussed, and potential implications from such activity are assessed.

  16. ReachScan - an Exposure Assessment Model

    EPA Pesticide Factsheets

    ReachScan estimates surface water concentrations downstream from industrial sites to assess impacts on the aquatic environment and potential dose rates for humans exposed via ingestion of drinking water and fish.

  17. Assessing Quality of Program Environments for Children and Youth with Autism: Autism Program Environment Rating Scale (APERS)

    ERIC Educational Resources Information Center

    Odom, Samuel L.; Cox, Ann; Sideris, John; Hume, Kara A.; Hedges, Susan; Kucharczyk, Suzanne; Shaw, Evelyn; Boyd, Brian A.; Reszka, Stephanie; Neitzel, Jennifer

    2018-01-01

    The purpose of this study was to examine the psychometric properties of the "Autism Program Environment Rating Scale" ("APERS"), an instrument designed to assess quality of program environments for students with autism spectrum disorder. Data sets from two samples of public school programs that provided services to children and…

  18. Simulation and assessment of SO2 toxic environment after ignition of uncontrolled sour gas flow of well blowout in hills.

    PubMed

    Zhu, Yuan; Chen, Guo-ming

    2010-06-15

    To study the sulfur dioxide (SO(2)) toxic environment after the ignition of uncontrolled sour gas flow of well blowout, we propose an integrated model to simulate the accident scenario and assess the consequences of SO(2) poisoning. The accident simulation is carried out based on computational fluid dynamics (CFD), which is composed of well blowout dynamics, combustion of sour gas, and products dispersion. Furthermore, detailed complex terrains are built and boundary layer flows are simulated according to Pasquill stability classes. Then based on the estimated exposure dose derived from the toxic dose-response relationship, quantitative assessment is carried out by using equivalent emergency response planning guideline (ERPG) concentration. In this case study, the contaminated areas are graded into three levels, and the areas, maximal influence distances, and main trajectories are predicted. We show that wind drives the contamination and its distribution to spread downwind, and terrains change the distribution shape through spatial aggregation and obstacles. As a result, the most dangerous regions are the downwind areas, the foot of the slopes, and depression areas such as valleys. These cause unfavorable influences on emergency response for accident control and public evacuation. In addition, the effectiveness of controlling the number of deaths by employing ignition is verified in theory. Based on the assessment results, we propose some suggestions for risk assessment, emergency response and accident decision making. Copyright 2010 Elsevier B.V. All rights reserved.

  19. DOSE-RESPONSE RELATIONSHIPS FOR MOLECULAR ALTERATIONS INDUCED BY B[ A ]P IN STRAIN A/J MOUSE LUNG

    EPA Science Inventory

    Benzo[a]pyrene (B[a]P) induces tumors in rodents at doses much higher than those found in the environment. Current cancer risk assessment of B[a]P assumes that the risk posed by low level exposure to B[a]P is linear with respect to dose. We have measur...

  20. 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.

  1. School Environment Handbook Part II: Environmental Awareness and Assessment of the School Environment.

    ERIC Educational Resources Information Center

    deHaas, Patricia; Gillespie, Judith

    This handbook is divided into two sections focusing on awareness and assessment activities designed to improve the total environment of the school. The activities can be used by one or more persons, and are appropriate for students, teachers, support staff, and administrators. The first section presents suggestions and activities to help explore…

  2. 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

  3. Assessment of Regional Pediatric Computed Tomography Dose Indices in Tamil Nadu.

    PubMed

    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 cm 3 pencil ion chamber with pediatric head and body polymethyl methacrylate phantoms. Dose data such as volumetric CT dose index (CTDI v ) and dose length product (DLP) on a minimum of twenty average-sized pediatric patients in each category were recorded to calculate a mean site CTDI v and DLP value. The rounded 75 th 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 (CTDI v 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 (CTDI v 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 CTDI v and DLP for head procedure were lower, and for chest and abdomen procedures were higher than European pediatric DRLs for both age groups.

  4. 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...

  5. Problem Solving Learning Environments and Assessment: A Knowledge Space Theory Approach

    ERIC Educational Resources Information Center

    Reimann, Peter; Kickmeier-Rust, Michael; Albert, Dietrich

    2013-01-01

    This paper explores the relation between problem solving learning environments (PSLEs) and assessment concepts. The general framework of evidence-centered assessment design is used to describe PSLEs in terms of assessment concepts, and to identify similarities between the process of assessment design and of PSLE design. We use a recently developed…

  6. Population dose near the Semipalatinsk test site.

    PubMed

    Hille, R; Hill, P; Bouisset, P; Calmet, D; Kluson, J; Seisebaev, A; Smagulov, S

    1998-10-01

    To determine the consequences of atmospheric atomic bomb tests for the population in the surroundings of the former nuclear weapons test site near Semipalatinsk in Kazakhstan, a pilot study was performed by an international cooperation between Kazakh, French, Czech and German institutions at two villages, Mostik and Maisk. Together with Kazakh scientists, eight experts from Europe carried out a field mission in September 1995 to assess, within the framework of a NATO supported project, the radiological situation as far as external doses, environmental contamination and body burden of man were concerned. A summary of the results obtained is presented. The actual radiological situation near the test site is characterized by fallout contaminations. Cs was found in upper soil layers in concentrations similar to those of the global fallout. Also Sr, Am and Co were observed. The resulting present dose to the population is low. Mean external doses from soil contamination for Maisk and Mostik (0.60-0.63 mSv/year) presently correspond to mean external doses in normal environments. Mean values of the annual internal doses observed in these two villages are below 2 microSv/year for 90Sr. For other radionuclides the internal doses are also negligible.

  7. Dose assessment of digital tomosynthesis in pediatric imaging

    NASA Astrophysics Data System (ADS)

    Gislason, Amber; Elbakri, Idris A.; Reed, Martin

    2009-02-01

    We investigated the potential for digital tomosynthesis (DT) to reduce pediatric x-ray dose while maintaining image quality. We utilized the DT feature (VolumeRadTM) on the GE DefiniumTM 8000 flat panel system installed in the Winnipeg Children's Hospital. Facial bones, cervical spine, thoracic spine, and knee of children aged 5, 10, and 15 years were represented by acrylic phantoms for DT dose measurements. Effective dose was estimated for DT and for corresponding digital radiography (DR) and computed tomography (CT) patient image sets. Anthropomorphic phantoms of selected body parts were imaged by DR, DT, and CT. Pediatric radiologists rated visualization of selected anatomic features in these images. Dose and image quality comparisons between DR, DT, and CT determined the usefulness of tomosynthesis for pediatric imaging. CT effective dose was highest; total DR effective dose was not always lowest - depending how many projections were in the DR image set. For the cervical spine, DT dose was close to and occasionally lower than DR dose. Expert radiologists rated visibility of the central facial complex in a skull phantom as better than DR and comparable to CT. Digital tomosynthesis has a significantly lower dose than CT. This study has demonstrated DT shows promise to replace CT for some facial bones and spinal diagnoses. Other clinical applications will be evaluated in the future.

  8. Dose, image quality and spine modeling assessment of biplanar EOS micro-dose radiographs for the follow-up of in-brace adolescent idiopathic scoliosis patients.

    PubMed

    Morel, Baptiste; Moueddeb, Sonia; Blondiaux, Eleonore; Richard, Stephen; Bachy, Manon; Vialle, Raphael; Ducou Le Pointe, Hubert

    2018-05-01

    The aim of this study was to compare the radiation dose, image quality and 3D spine parameter measurements of EOS low-dose and micro-dose protocols for in-brace adolescent idiopathic scoliosis (AIS) patients. We prospectively included 25 consecutive patients (20 females, 5 males) followed for AIS and undergoing brace treatment. The mean age was 12 years (SD 2 years, range 8-15 years). For each patient, in-brace biplanar EOS radiographs were acquired in a standing position using both the conventional low-dose and micro-dose protocols. Dose area product (DAP) was systematically recorded. Diagnostic image quality was qualitatively assessed by two radiologists for visibility of anatomical structures. The reliability of 3D spine modeling between two operators was quantitatively evaluated for the most clinically relevant 3D radiological parameters using intraclass correlation coefficient (ICC). The mean DAP for the posteroanterior and lateral acquisitions was 300 ± 134 and 433 ± 181 mGy cm 2 for the low-dose radiographs, and 41 ± 19 and 81 ± 39 mGy cm 2 for micro-dose radiographs. Image quality was lower with the micro-dose protocol. The agreement was "good" to "very good" for all measured clinical parameters when comparing the low-dose and micro-dose protocols (ICC > 0.73). The micro-dose protocol substantially reduced the delivered dose (by a factor of 5-7 compared to the low-dose protocol) in braced children with AIS. Although image quality was reduced, the micro-dose protocol proved to be adapted to radiological follow-up, with adequate image quality and reliable clinical measurements. These slides can be retrieved under Electronic Supplementary Material.

  9. 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...

  10. SU-F-I-38: Patient Organ Specific Dose Assessment in Coronary CT Angiograph Using Voxellaized Volume Dose Index in Monte Carlo Simulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fallal, Mohammadi Gh.; Riyahi, Alam N.; Graily, Gh.

    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-systemmore » 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

  11. Use of a channelized Hotelling observer to assess CT image quality and optimize dose reduction for iteratively reconstructed images.

    PubMed

    Favazza, Christopher P; Ferrero, Andrea; Yu, Lifeng; Leng, Shuai; McMillan, Kyle L; McCollough, Cynthia H

    2017-07-01

    The use of iterative reconstruction (IR) algorithms in CT generally decreases image noise and enables dose reduction. However, the amount of dose reduction possible using IR without sacrificing diagnostic performance is difficult to assess with conventional image quality metrics. Through this investigation, achievable dose reduction using a commercially available IR algorithm without loss of low contrast spatial resolution was determined with a channelized Hotelling observer (CHO) model and used to optimize a clinical abdomen/pelvis exam protocol. A phantom containing 21 low contrast disks-three different contrast levels and seven different diameters-was imaged at different dose levels. Images were created with filtered backprojection (FBP) and IR. The CHO was tasked with detecting the low contrast disks. CHO performance indicated dose could be reduced by 22% to 25% without compromising low contrast detectability (as compared to full-dose FBP images) whereas 50% or more dose reduction significantly reduced detection performance. Importantly, default settings for the scanner and protocol investigated reduced dose by upward of 75%. Subsequently, CHO-based protocol changes to the default protocol yielded images of higher quality and doses more consistent with values from a larger, dose-optimized scanner fleet. CHO assessment provided objective data to successfully optimize a clinical CT acquisition protocol.

  12. Mars' surface radiation environment measured with the Mars Science Laboratory's Curiosity rover.

    PubMed

    Hassler, Donald M; Zeitlin, Cary; Wimmer-Schweingruber, Robert F; Ehresmann, Bent; Rafkin, Scot; Eigenbrode, Jennifer L; Brinza, David E; Weigle, Gerald; Böttcher, Stephan; Böhm, Eckart; Burmeister, Soenke; Guo, Jingnan; Köhler, Jan; Martin, Cesar; Reitz, Guenther; Cucinotta, Francis A; Kim, Myung-Hee; Grinspoon, David; Bullock, Mark A; Posner, Arik; Gómez-Elvira, Javier; Vasavada, Ashwin; Grotzinger, John P

    2014-01-24

    The Radiation Assessment Detector (RAD) on the Mars Science Laboratory's Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.

  13. Assessment of Volumetric-Modulated Arc Therapy for Constant and Variable Dose Rates

    PubMed Central

    De Ornelas-Couto, Mariluz; Mihaylov, Ivaylo; Dogan, Nesrin

    2017-01-01

    Purpose: The aim of this study is to compare the effects of dose rate on volumetric-modulated arc therapy plans to determine optimal dose rates for prostate and head and neck (HN) cases. Materials and Methods: Ten prostate and ten HN cases were retrospectively studied. For each case, seven plans were generated: one variable dose rate (VDR) and six constant dose rate (CDR) (100–600 monitor units [MUs]/min) plans. Prescription doses were: 80 Gy to planning target volume (PTV) for the prostate cases, and 70, 60, and 54 Gy to PTV1, PTV2, and PTV3, respectively, for HN cases. Plans were normalized to 95% of the PTV and PTV1, respectively, with the prescription dose. Plans were assessed using Dose-Volume-Histogram metrics, homogeneity index, conformity index, MUs, and delivery time. Results: For the prostate cases, significant differences were found for rectum D35 between VDR and all CDR plans, except CDR500. Furthermore, VDR was significantly different than CDR100 and 200 for bladder D50. Delivery time for all CDR plans and MUs for CDR400–600 were significantly higher when compared to VDR. HN cases showed significant differences between VDR and CDR100, 500 and 600 for D2 to the cord and brainstem. Significant differences were found for delivery time and MUs for all CDR plans, except CDR100 for number of MUs. Conclusion: The most significant differences were observed in delivery time and number of MUs. All-in-all, the best CDR for prostate cases was found to be 300 MUs/min and 200 or 300 MUs/min for HN cases. However, VDR plans are still the choice in terms of MU efficiency and plan quality. PMID:29296033

  14. Assessment of target dose delivery in anal cancer using in vivo thermoluminescent dosimetry.

    PubMed

    Weber, D C; Nouet, P; Kurtz, J M; Allal, A S

    2001-04-01

    To measure anal dose during external beam radiotherapy (EBRT) using in vivo dosimetry, to study the difference of measured from prescribed dose values, and to evaluate possible associations of such differences with acute and late skin/mucosal toxicity and anorectal function. Thirty-one patients with localized anal carcinoma underwent in vivo measurements during the first EBRT session. Themoluminescent dosimeters (TLD) were placed at the center of the anal verge according to a localization protocol. No bolus was used. Patients received a median dose of 39.6 Gy (range: 36-45 Gy) by anteroposterior opposed AP/PA pelvic fields with 6 or 18 MV photons, followed by a median boost dose of 20 Gy (range: 13-24 Gy). Concomitant chemotherapy (CCT), consisting of 1-2 cycles of continuous infusion 5-fluorouracil (5-FU) and bolus mitomycin-C (MMC), was usually administered during the first weeks of the pelvic and boost EBRT courses. Acute and late skin/mucosal reactions were recorded according to the Radiation Therapy Oncology Group (RTOG) toxicity scale. Anal sphincter function was assessed using the Memorial Sloan Kettering Cancer Center (MSKCC) scale. TLD anal doses differed by a mean of 5.8% (SD: 5.8) in comparison to the central axis prescribed dose. Differences of at least 10% and at least 15% were observed in eight (26%) and three (9.7%) patients, respectively. TLD doses did not significantly correlate with acute or late grade 2-3 skin or mucosal toxicity. However, patients having good-fair MSKCC anal function had a significantly greater mean difference in anal TLD dose (10.5%, SD: 5.9) than patients having excellent function (3.8%, SD: 4.6) (P = 0.004). Prescribed dose values, length of follow-up, and age at diagnosis did not correlate with late sphincter function. These data show that AP/PA fields using megavoltage photons deliver adequate dose to the anal verge. However, in about one quarter of patients treated with this technique the anal dose varied from the

  15. 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…

  16. Environment, Safety, and Health Self-Assessment Report, Fiscal Year 2008

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chernowski, John

    2009-02-27

    Lawrence Berkeley National Laboratory's Environment, Safety, and Health (ES&H) Self-Assessment Program ensures that Integrated Safety Management (ISM) is implemented institutionally and by all divisions. The Self-Assessment Program, managed by the Office of Contract Assurance (OCA), provides for an internal evaluation of all ES&H programs and systems at LBNL. The functions of the program are to ensure that work is conducted safely, and with minimal negative impact to workers, the public, and the environment. The Self-Assessment Program is also the mechanism used to institute continuous improvements to the Laboratory's ES&H programs. The program is described in LBNL/PUB 5344, Environment, Safety, andmore » Health Self-Assessment Program and is composed of four distinct assessments: the Division Self-Assessment, the Management of Environment, Safety, and Health (MESH) review, ES&H Technical Assurance, and the Appendix B Self-Assessment. The Division Self-Assessment uses the five core functions and seven guiding principles of ISM as the basis of evaluation. Metrics are created to measure performance in fulfilling ISM core functions and guiding principles, as well as promoting compliance with applicable regulations. The five core functions of ISM are as follows: (1) Define the Scope of Work; (2) Identify and Analyze Hazards; (3) Control the Hazards; (4) Perform the Work; and (5) Feedback and Improvement. The seven guiding principles of ISM are as follows: (1) Line Management Responsibility for ES&H; (2) Clear Roles and Responsibilities; (3) Competence Commensurate with Responsibilities; (4) Balanced Priorities; (5) Identification of ES&H Standards and Requirements; (6) Hazard Controls Tailored to the Work Performed; and (7) Operations Authorization. Performance indicators are developed by consensus with OCA, representatives from each division, and Environment, Health, and Safety (EH&S) Division program managers. Line management of each division performs the Division

  17. 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

  18. 3D delivered dose assessment using a 4DCT-based motion model

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cai, Weixing; Hurwitz, Martina H.; Williams, Christopher L.

    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.« less

  19. An updated dose assessment for resettlement options at Bikini Atoll--a U.S. nuclear test site.

    PubMed

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

    1997-07-01

    On 1 March 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 1978. The unique composition of coral soil greatly alters the relative contribution of 137Cs and 90Sr to the total estimated dose relative to expectations based on North American and European soils. Without counter measures, 137Cs 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 30-, 50-, and 70-y integral effective doses are 91 mSv, 130 mSv, and 150 mSv, respectively. A detailed uncertainty analysis for these dose estimates is presented in a companion paper in this issue. We have evaluated various countermeasures to reduce 137Cs in food crops. Treatment with potassium reduces the uptake of 137Cs into food crops, and therefore the ingestion dose, to about 5% of pretreatment levels and has essentially no negative environmental consequences. We have calculated the dose for the rehabilitation scenario where the top 40 cm of soil is removed in the housing and village area, and the rest of the island is treated with potassium fertilizer; the maximum annual effective dose is 0.41 mSv and the 30-, 50-, and 70-y

  20. 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.

  1. A dose assessment method for arbitrary geometries with virtual reality in the nuclear facilities decommissioning

    NASA Astrophysics Data System (ADS)

    Chao, Nan; Liu, Yong-kuo; Xia, Hong; Ayodeji, Abiodun; Bai, Lu

    2018-03-01

    During the decommissioning of nuclear facilities, a large number of cutting and demolition activities are performed, which results in a frequent change in the structure and produce many irregular objects. In order to assess dose rates during the cutting and demolition process, a flexible dose assessment method for arbitrary geometries and radiation sources was proposed based on virtual reality technology and Point-Kernel method. The initial geometry is designed with the three-dimensional computer-aided design tools. An approximate model is built automatically in the process of geometric modeling via three procedures namely: space division, rough modeling of the body and fine modeling of the surface, all in combination with collision detection of virtual reality technology. Then point kernels are generated by sampling within the approximate model, and when the material and radiometric attributes are inputted, dose rates can be calculated with the Point-Kernel method. To account for radiation scattering effects, buildup factors are calculated with the Geometric-Progression formula in the fitting function. The effectiveness and accuracy of the proposed method was verified by means of simulations using different geometries and the dose rate results were compared with that derived from CIDEC code, MCNP code and experimental measurements.

  2. 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 CO 2 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.

  3. Improving Exposure Science and Dose Metrics for Toxicity Testing, Screening, Prioritizing, and Risk Assessment

    EPA Science Inventory

    Advance the characterization of exposure and dose metrics required to translate advances and findings in computational toxicology to information that can be directly used to support exposure and risk assessment for decision making and improved public health.

  4. 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

  5. Remote online ergonomic assessment in the office environment as compared to face-to-face ergonomic assessment.

    PubMed

    Eyal, Levy; Ribak, Joseph; Badihi, Yehuda

    2012-01-01

    remote online ergonomic assessment in the office environment as compared to face-to-face ergonomic assessment and examination of the applicability of remote online ergonomic assessment to office workers. 40 employees from a large Israeli hi-tech company were ergonomically assessed per the University of California computer usage checklist, according to the two assessment types (face-to-face and remote). An additional Ergonomist "assessor 2" examined the credibility of the process. Research hypothesis 1 was verified: 21 out of 22 questions (95.45%) from the checklist indicated compatibility between "assessor 1" to the "Gold Standard" at an 80% level. Research hypothesis 2: examining the credibility between the assessors with regard to remote assessment. This hypothesis was partially verified, the correlation between the assessors was measured at 0.54. Research hypothesis 3: examining the extent of deviation of natural posture between distal body parts assessment (distant from the center of the body) and proximal body parts (close to the center of the body). This hypothesis was clearly verified. It has been proven that there is statistical significance between the results. The current research has proved that there is an additional method to assess musculoskeletal disorders risk factors remotely online at office environment.

  6. Virtual environment assessment for laser-based vision surface profiling

    NASA Astrophysics Data System (ADS)

    ElSoussi, Adnane; Al Alami, Abed ElRahman; Abu-Nabah, Bassam A.

    2015-03-01

    Oil and gas businesses have been raising the demand from original equipment manufacturers (OEMs) to implement a reliable metrology method in assessing surface profiles of welds before and after grinding. This certainly mandates the deviation from the commonly used surface measurement gauges, which are not only operator dependent, but also limited to discrete measurements along the weld. Due to its potential accuracy and speed, the use of laser-based vision surface profiling systems have been progressively rising as part of manufacturing quality control. This effort presents a virtual environment that lends itself for developing and evaluating existing laser vision sensor (LVS) calibration and measurement techniques. A combination of two known calibration techniques is implemented to deliver a calibrated LVS system. System calibration is implemented virtually and experimentally to scan simulated and 3D printed features of known profiles, respectively. Scanned data is inverted and compared with the input profiles to validate the virtual environment capability for LVS surface profiling and preliminary assess the measurement technique for weld profiling applications. Moreover, this effort brings 3D scanning capability a step closer towards robust quality control applications in a manufacturing environment.

  7. Comparison of eye-lens doses imparted during interventional and non-interventional neuroimaging techniques for assessment of intracranial aneurysms.

    PubMed

    Guberina, N; Dietrich, U; Forsting, M; Ringelstein, A

    2018-02-01

    A neurointerventional examination of intracranial aneurysms often involves the eye lens in the primary beam of radiation. To assess and compare eye-lens doses imparted during interventional and non-interventional imaging techniques for the examination of intracranial aneurysms. We performed a phantom study on an anthropomorphic phantom (ATOM dosimetry phantom 702-D; CIRS, Norfolk, Virginia, USA) and assessed eye-lens doses with thermoluminescent dosimeters (TLDs) type 100 (LiF:Mg, Ti) during (1) interventional (depiction of all cerebral arteries with triple 3D-rotational angiography and twice 2-plane DSA anteroposterior and lateral projections) and (2) non-interventional (CT angiography (CTA)) diagnosis of intracranial aneurysms. Eye-lens doses were calculated following recommendations of the ICRP 103. Image quality was analysed in retrospective by two experienced radiologists on the basis of non-interventional and interventional pan-angiography examinations of patients with incidental aneurysms (n=50) on a five-point Likert scale. The following eye-lens doses were assessed: (1) interventional setting (triple 3D-rotational angiography and twice 2-plane DSA anteroposterior and lateral projections) 12 mGy; (2) non-interventional setting (CTA) 4.1 mGy. Image quality for depiction of intracranial aneurysms (>3 mm) was evaluated as good by both readers for both imaging techniques. Eye-lens doses are markedly higher during the interventional than during the non-interventional diagnosis of intracranial aneurysms. For the eye-lens dose, CTA offers considerable radiation dose savings in the diagnosis of intracranial aneurysms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  8. Indicators for Environment Health Risk Assessment in the Jiangsu Province of China

    PubMed Central

    Zhang, Shujie; Wei, Zhengzheng; Liu, Wenliang; Yao, Ling; Suo, Wenyu; Xing, Jingjing; Huang, Bingzhao; Jin, Di; Wang, Jiansheng

    2015-01-01

    According to the framework of “Pressure-State-Response”, this study established an indicator system which can reflect comprehensive risk of environment and health for an area at large scale. This indicator system includes 17 specific indicators covering social and economic development, pollution emission intensity, air pollution exposure, population vulnerability, living standards, medical and public health, culture and education. A corresponding weight was given to each indicator through Analytical Hierarchy Process (AHP) method. Comprehensive risk assessment of the environment and health of 58 counties was conducted in the Jiangsu province, China, and the assessment result was divided into four types according to risk level. Higher-risk counties are all located in the economically developed southern region of Jiangsu province and relatively high-risk counties are located along the Yangtze River and Xuzhou County and its surrounding areas. The spatial distribution of relatively low-risk counties is dispersive, and lower-risk counties mainly located in the middle region where the economy is somewhat weaker in the province. The assessment results provide reasonable and scientific basis for Jiangsu province Government in formulating environment and health policy. Moreover, it also provides a method reference for the comprehensive risk assessment of environment and health within a large area (provinces, regions and countries). PMID:26371016

  9. Indicators for Environment Health Risk Assessment in the Jiangsu Province of China.

    PubMed

    Zhang, Shujie; Wei, Zhengzheng; Liu, Wenliang; Yao, Ling; Suo, Wenyu; Xing, Jingjing; Huang, Bingzhao; Jin, Di; Wang, Jiansheng

    2015-09-07

    According to the framework of "Pressure-State-Response", this study established an indicator system which can reflect comprehensive risk of environment and health for an area at large scale. This indicator system includes 17 specific indicators covering social and economic development, pollution emission intensity, air pollution exposure, population vulnerability, living standards, medical and public health, culture and education. A corresponding weight was given to each indicator through Analytical Hierarchy Process (AHP) method. Comprehensive risk assessment of the environment and health of 58 counties was conducted in the Jiangsu province, China, and the assessment result was divided into four types according to risk level. Higher-risk counties are all located in the economically developed southern region of Jiangsu province and relatively high-risk counties are located along the Yangtze River and Xuzhou County and its surrounding areas. The spatial distribution of relatively low-risk counties is dispersive, and lower-risk counties mainly located in the middle region where the economy is somewhat weaker in the province. The assessment results provide reasonable and scientific basis for Jiangsu province Government in formulating environment and health policy. Moreover, it also provides a method reference for the comprehensive risk assessment of environment and health within a large area (provinces, regions and countries).

  10. Systematic analysis of the scatter environment in clinical intra-operative high dose rate (IOHDR) brachytherapy

    NASA Astrophysics Data System (ADS)

    Oh, Moonseong

    Most brachytherapy planning systems are based on a dose calculation algorithm that assumes an infinite scatter environment surrounding the target volume and applicator. In intra-operative high dose rate brachytherapy (IOHDR) where treatment catheters are typically laid either directly on a tumor bed or within applicators that may have little or no scatter material above them, the lack of scatter from one side of the applicator can result in serious underdosage during treatment. Therefore, full analyses of the physical processes such as the photoelectric effect, Rayleigh, and Compton scattering that contribute to dosimetric errors have to be investigated and documented to result in more accurate treatment delivery to patients undergoing IOHDR procedures. Monte Carlo simulation results showed the Compton scattering effect is about 40 times more probable than photoelectric effect for the treated areas of single source, 4 x 4, and 2 x 4 cm2. Also, the dose variations with and without photoelectric effect were 0.3 ˜ 0.7%, which are within the uncertainty in Monte Carlo simulations. Also, Monte Carlo simulation studies were done to verify the following experimental results for quantification of dosimetric errors in clinical IOHDR brachytherapy. The first experimental study was performed to quantify the inaccuracy in clinical dose delivery due to the incomplete scatter conditions inherent in IOHDR brachytherapy. Treatment plans were developed for 3 different treatment surface areas (4 x 4, 7 x 7, 12 x 12 cm2), each with prescription points located at 3 distances (0.5 cm, 1.0 cm, and 1.5 cm) from the source dwell positions. Measurements showed that the magnitude of the underdosage varies from about 8% to 13% of the prescription dose as the prescription depth is increased from 0.5 cm to 1.5 cm. This treatment error was found to be independent of the irradiated area and strongly dependent on the prescription distance. The study was extended to confirm the underdosage for

  11. Environment, Safety and Health Self-Assessment Report Fiscal Year 2010

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Robinson, Scott

    2011-03-23

    The Lawrence Berkeley National Laboratory (LBNL) Environment, Safety, and Health (ES&H) Self-Assessment Program was established to ensure that Integrated Safety Management (ISM) is implemented institutionally and by all divisions. The ES&H Self-Assessment Program, managed by the Office of Contractor Assurance (OCA), provides for an internal evaluation of all ES&H programs and systems at LBNL. The primary objective of the program is to ensure that work is conducted safely and with minimal negative impact to workers, the public, and the environment. Self-assessment follows the five core functions and guiding principles of ISM. Self-assessment is the mechanism used to promote the continuousmore » improvement of the Laboratory's ES&H programs. The process is described in the Environment, Safety, and Health Assurance Plan (PUB-5344) and is composed of three types of self-assessments: Division ES&H Self-Assessment, ES&H Technical Assurance Program Assessment, and Division ES&H Peer Review. The Division ES&H Self-Assessment Manual (PUB-3105) provides the framework by which divisions conduct formal ES&H self-assessments to systematically identify program deficiencies. Issue-specific assessments are designed and implemented by the divisions and focus on areas of interest to division management. They may be conducted by teams and involve advance planning to ensure that appropriate resources are available. The ES&H Technical Assurance Program Manual (PUB-913E) provides the framework for systematic reviews of ES&H programs and processes. The ES&H Technical Assurance Program Assessment is designed to evaluate whether ES&H programs and processes are compliant with guiding regulations, are effective, and are properly implemented by LBNL divisions. The Division ES&H Peer Review Manual provides the framework by which division ISM systems are evaluated and improved. Peer Reviews are conducted by teams under the direction of senior division management and focus on higher

  12. An assessment of mumps vaccine effectiveness by dose during an outbreak in Canada

    PubMed Central

    Deeks, Shelley L.; Lim, Gillian H.; Simpson, Mary Anne; Gagné, Louise; Gubbay, Jonathan; Kristjanson, Erik; Fung, Cecilia; Crowcroft, Natasha S.

    2011-01-01

    Background This investigation was done to assess vaccine effectiveness of one and two doses of the measles, mumps and rubella (MMR) vaccine during an outbreak of mumps in Ontario. The level of coverage required to reach herd immunity and interrupt community transmission of mumps was also estimated. Methods Information on confirmed cases of mumps was retrieved from Ontario’s integrated Public Health Information System. Cases that occurred between Sept. 1, 2009, and June 10, 2010, were included. Selected health units supplied coverage data from the Ontario Immunization Record Information System. Vaccine effectiveness by dose was calculated using the screening method. The basic reproductive number (R0) represents the average number of new infections per case in a fully susceptile population, and R0 values of between 4 and 10 were considered for varying levels of vaccine effectiveness. Results A total of 134 confirmed cases of mumps were identified. Information on receipt of MMR vaccine was available for 114 (85.1%) cases, of whom 63 (55.3%) reported having received only one dose of vaccine; 32 (28.1%) reported having received two doses. Vaccine effectiveness of one dose of the MMR vaccine ranged from 49.2% to 81.6%, whereas vaccine effectiveness of two doses ranged from 66.3% to 88.0%. If we assume vaccine effectiveness of 85% for two doses of the vaccine, vaccine coverage of 88.2% and 98.0% would be needed to interrupt community transmission of mumps if the corresponding reproductive values were four and six. Interpretation Our estimates of vaccine effectiveness of one and two doses of mumps-containing vaccine were consistent with the estimates that have been reported in other outbreaks. Outbreaks occurring in Ontario and elsewhere serve as a warning against complacency over vaccination programs. PMID:21576295

  13. An assessment of mumps vaccine effectiveness by dose during an outbreak in Canada.

    PubMed

    Deeks, Shelley L; Lim, Gillian H; Simpson, Mary Anne; Gagné, Louise; Gubbay, Jonathan; Kristjanson, Erik; Fung, Cecilia; Crowcroft, Natasha S

    2011-06-14

    This investigation was done to assess vaccine effectiveness of one and two doses of the measles, mumps and rubella (MMR) vaccine during an outbreak of mumps in Ontario. The level of coverage required to reach herd immunity and interrupt community transmission of mumps was also estimated. Information on confirmed cases of mumps was retrieved from Ontario's integrated Public Health Information System. Cases that occurred between Sept. 1, 2009, and June 10, 2010, were included. Selected health units supplied coverage data from the Ontario Immunization Record Information System. Vaccine effectiveness by dose was calculated using the screening method. The basic reproductive number (R(0)) represents the average number of new infections per case in a fully susceptible population, and R(0) values of between 4 and 10 were considered for varying levels of vaccine effectiveness. A total of 134 confirmed cases of mumps were identified. Information on receipt of MMR vaccine was available for 114 (85.1%) cases, of whom 63 (55.3%) reported having received only one dose of vaccine; 32 (28.1%) reported having received two doses. Vaccine effectiveness of one dose of the MMR vaccine ranged from 49.2% to 81.6%, whereas vaccine effectiveness of two doses ranged from 66.3% to 88.0%. If we assume vaccine effectiveness of 85% for two doses of the vaccine, vaccine coverage of 88.2% and 98.0% would be needed to interrupt community transmission of mumps if the corresponding reproductive values were four and six. Our estimates of vaccine effectiveness of one and two doses of mumps-containing vaccine were consistent with the estimates that have been reported in other outbreaks. Outbreaks occurring in Ontario and elsewhere serve as a warning against complacency over vaccination programs.

  14. 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.

  15. 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

  16. 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

  17. Assessment of bioequivalence of rifampicin, isoniazid and pyrazinamide in a four drug fixed dose combination with separate formulations at the same dose levels.

    PubMed

    Agrawal, Shrutidevi; Kaur, Kanwal Jit; Singh, Inderjit; Bhade, Shantaram R; Kaul, Chaman Lal; Panchagnula, Ramesh

    2002-02-21

    Tuberculosis (TB) needs treatment with three to five different drugs simultaneously, depending on the patient category. These drugs can be given as single drug preparations or fixed dose combinations (FDCs) of two more drugs in a single formulation. World Health Organization and International Union against Tuberculosis and Lung Disease (IUATLD) recommend FDCs only of proven bioavailability. The relative bioavailability of rifampicin (RIF), isoniazid (INH) and pyrazinamide (PYZ) was assessed on a group of 13 healthy male subjects from a four drug FDC versus separate formulations at the same dose levels. The study was designed to be an open, crossover experiment. A total of nine blood samples each of 3 ml volume were collected over a period of 24-h. The concentrations of RIF, its main metabolite desacetyl RIF (DRIF), INH and PYZ in plasma were assessed by HPLC analysis. Pharmacokinetic parameters namely AUC(0-24), AUC(0-inf), C(max), T(max), were calculated and subjected to different statistical tests (Hauschke analysis, two way ANOVA, normal and log transformed confidence interval) at 90% confidence interval. In addition, elimination rate constant (K(el)) and absorption efficiencies for each drug were also calculated. It was concluded that four drugs FDC tablet is bioequivalent for RIF, INH and PYZ to separate formulation at the same dose levels.

  18. Occupational Exposure of the Eye Lens in Interventional Procedures: How to Assess and Manage Radiation Dose.

    PubMed

    Ciraj-Bjelac, Olivera; Carinou, Eleftheria; Ferrari, Paolo; Gingaume, Merce; Merce, Marta Sans; O'Connor, Una

    2016-11-01

    Occupational exposure from interventional x-ray procedures is one of the areas in which increased eye lens exposure may occur. Accurate dosimetry is an important element to investigate the correlation of observed radiation effects with radiation dose, to verify the compliance with regulatory dose limits, and to optimize radiation protection practice. The objective of this work is to review eye lens dose levels in clinical practice that may occur from the use of ionizing radiation. The use of a dedicated eye lens dosimeter is the recommended methodology; however, in practice it cannot always be easily implemented. Alternatively, the eye lens dose could be assessed from measurements of other dosimetric quantities or other indirect parameters, such as patient dose. The practical implementation of monitoring eye lens doses and the use of adequate protective equipment still remains a challenge. The use of lead glasses with a good fit to the face, appropriate lateral coverage, and/or ceiling-suspended screens is recommended in workplaces with potential high eye lens doses. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  19. Development and Validation of a Questionnaire to Assess Carbohydrate and Insulin-Dosing Knowledge in Youth With Type 1 Diabetes

    PubMed Central

    Koontz, Michaela B.; Cuttler, Leona; Palmert, Mark R.; O'Riordan, MaryAnn; Borawski, Elaine A.; McConnell, Judy; Kern, Elizabeth O.

    2010-01-01

    OBJECTIVE The American Diabetes Association advocates insulin regimens for youth with type 1 diabetes that involve adjusting insulin dose based on carbohydrate intake and blood glucose level. Implementing these regimens requires knowledge about carbohydrate content of foods and subsequent calculations of insulin dose, skills that may be difficult to gauge in practice. Therefore, we sought to develop and validate a questionnaire, the PedCarbQuiz (PCQ), to assess carbohydrate and insulin-dosing knowledge in youth with type 1 diabetes. RESEARCH DESIGN AND METHODS After development by an expert panel, the PCQ was administered to 75 youth with type 1 diabetes or their parents. Reliability was assessed by Cronbach α and split-half testing. To assess validity, scores were correlated with A1C, expert assessments, parent educational level, and complexity of insulin regimen. RESULTS PCQ mean score was 87 ± 9.7% (range 42–98%). Cronbach α was 0.88, and correlation of split halves was 0.59 (P < 0.0001). Higher PCQ scores correlated significantly with lower A1C (r = −0.29, P = 0.01) and expert assessments (r = 0.56, P < 0.001). Scores were significantly higher in parents with college degrees than in those without (P = 0.01) and in participants with more complex insulin regimens (P = 0.003). CONCLUSIONS The PCQ is a novel, easily administered instrument to assess knowledge about carbohydrates and insulin dosing calculations. Initial analyses support the reliability and validity of the PCQ. PMID:20007940

  20. Development and validation of a questionnaire to assess carbohydrate and insulin-dosing knowledge in youth with type 1 diabetes.

    PubMed

    Koontz, Michaela B; Cuttler, Leona; Palmert, Mark R; O'Riordan, Maryann; Borawski, Elaine A; McConnell, Judy; Kern, Elizabeth O

    2010-03-01

    OBJECTIVE The American Diabetes Association advocates insulin regimens for youth with type 1 diabetes that involve adjusting insulin dose based on carbohydrate intake and blood glucose level. Implementing these regimens requires knowledge about carbohydrate content of foods and subsequent calculations of insulin dose, skills that may be difficult to gauge in practice. Therefore, we sought to develop and validate a questionnaire, the PedCarbQuiz (PCQ), to assess carbohydrate and insulin-dosing knowledge in youth with type 1 diabetes. RESEARCH DESIGN AND METHODS After development by an expert panel, the PCQ was administered to 75 youth with type 1 diabetes or their parents. Reliability was assessed by Cronbach alpha and split-half testing. To assess validity, scores were correlated with A1C, expert assessments, parent educational level, and complexity of insulin regimen. RESULTS PCQ mean score was 87 +/- 9.7% (range 42-98%). Cronbach alpha was 0.88, and correlation of split halves was 0.59 (P < 0.0001). Higher PCQ scores correlated significantly with lower A1C (r = -0.29, P = 0.01) and expert assessments (r = 0.56, P < 0.001). Scores were significantly higher in parents with college degrees than in those without (P = 0.01) and in participants with more complex insulin regimens (P = 0.003). CONCLUSIONS The PCQ is a novel, easily administered instrument to assess knowledge about carbohydrates and insulin dosing calculations. Initial analyses support the reliability and validity of the PCQ.

  1. Radiometric surveying for the assessment of radiation dose and radon specific exhalation in underground environment

    NASA Astrophysics Data System (ADS)

    Bochiolo, M.; Verdoya, M.; Chiozzi, P.; Pasquale, V.

    2012-08-01

    We performed a radiometric survey for evaluating the natural radioactivity and the related potential hazard level both outdoor and indoor a mine tunnel. The mine is located in a zone of uranium enrichment in the Western Alps (Italy). At first, a γ-ray spectrometry survey of the area surrounding the mine was carried out to define the extent of the ore deposit. Then, spectrometric measurements were performed in the tunnel and rock samples were collected for laboratory analyses. The results point to significant heterogeneity in uranium concentration and consequently in the absorbed dose rate spatial distribution. Spectrometric results in situ and in the laboratory, together with radon air concentration measurements, were used to infer the radon specific exhalation and flow from the mine rocks. The specific exhalation is positively related to the activity concentration of uranium.

  2. 76 FR 38399 - Assessing the Current Research, Policy, and Practice Environment in Public Health Genomics

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-30

    ... CDC-2011-0008] Assessing the Current Research, Policy, and Practice Environment in Public Health... information helpful to assess the current research, policy, and practice environment in public health genomics. HHS/CDC is currently leading a process to assess the most important steps for public health genomics...

  3. 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.

  4. Real-time 3D radiation risk assessment supporting simulation of work in nuclear environments.

    PubMed

    Szőke, I; Louka, M N; Bryntesen, T R; Bratteli, J; Edvardsen, S T; RøEitrheim, K K; Bodor, K

    2014-06-01

    This paper describes the latest developments at the Institute for Energy Technology (IFE) in Norway, in the field of real-time 3D (three-dimensional) radiation risk assessment for the support of work simulation in nuclear environments. 3D computer simulation can greatly facilitate efficient work planning, briefing, and training of workers. It can also support communication within and between work teams, and with advisors, regulators, the media and public, at all the stages of a nuclear installation's lifecycle. Furthermore, it is also a beneficial tool for reviewing current work practices in order to identify possible gaps in procedures, as well as to support the updating of international recommendations, dissemination of experience, and education of the current and future generation of workers.IFE has been involved in research and development into the application of 3D computer simulation and virtual reality (VR) technology to support work in radiological environments in the nuclear sector since the mid 1990s. During this process, two significant software tools have been developed, the VRdose system and the Halden Planner, and a number of publications have been produced to contribute to improving the safety culture in the nuclear industry.This paper describes the radiation risk assessment techniques applied in earlier versions of the VRdose system and the Halden Planner, for visualising radiation fields and calculating dose, and presents new developments towards implementing a flexible and up-to-date dosimetric package in these 3D software tools, based on new developments in the field of radiation protection. The latest versions of these 3D tools are capable of more accurate risk estimation, permit more flexibility via a range of user choices, and are applicable to a wider range of irradiation situations than their predecessors.

  5. 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. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  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. Initial assessment of image quality for low-dose PET: evaluation of lesion detectability.

    PubMed

    Schaefferkoetter, Joshua D; Yan, Jianhua; Townsend, David W; Conti, Maurizio

    2015-07-21

    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.

  8. 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.

  9. Assessing culturally sensitive factors in the learning environment of science classrooms

    NASA Astrophysics Data System (ADS)

    Fisher, Darrell L.; Waldrip, Bruce G.

    1997-03-01

    As schools are becoming increasingly diverse in their scope and clientele, any examination of the interaction of culturally sensitive factors of students' learning environments with learning science assumes critical importance. The purpose of this exploratory study was to develop an instrument to assess learning environment factors that are culturally sensitive, to provide initial validation information on the instrument and to examine associations between students' perceptions of their learning environments and their attitudes towards science and achievement of enquiry skills. A measure of these factors of science student's learning environment, namely the Cultural Learning Environment Questionnaire (CLEQ), was developed from past learning environment instruments and influenced by Hofstede's four dimensions of culture (Power Distance, Uncertainty Avoidance, Individualism, and Masculinity/Femininity). The reliability and discriminant validity for each scale were obtained and associations between learning environment, attitude to science and enquiry skills achievement were found.

  10. SU-E-T-616: Plan Quality Assessment of Both Treatment Planning System Dose and Measurement-Based 3D Reconstructed Dose in the Patient

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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: Elevenmore » 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

  11. 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.

  12. Biota dose assessment of small mammals sampled near uranium mines in northern Arizona

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jannik, T.; Minter, K.; Kuhne, W.

    In 2015, the U. S. Geological Survey (USGS) collected approximately 50 small mammal carcasses from Northern Arizona uranium mines and other background locations. Based on the highest gross alpha results, 11 small mammal samples were selected for radioisotopic analyses. None of the background samples had significant gross alpha results. The 11 small mammals were identified relative to the three ‘indicator’ mines located south of Fredonia, AZ on the Kanab Plateau (Kanab North Mine, Pinenut Mine, and Arizona 1 Mine) (Figure 1-1) and are operated by Energy Fuels Resources Inc. (EFRI). EFRI annually reports soil analysis for uranium and radium-226 usingmore » Arizona Department of Environmental Quality (ADEQ)-approved Standard Operating Procedures for Soil Sampling (EFRI 2016a, 2016b, 2017). In combination with the USGS small mammal radioiosotopic tissue analyses, a biota dose assessment was completed by Savannah River National Laboratory (SRNL) using the RESidual RADioactivity-BIOTA (RESRAD-BIOTA, V. 1.8) dose assessment tool provided by the Argonne National Laboratory (ANL 2017).« less

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

    PubMed

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

    2012-01-01

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

  14. Consequences of the Chernobyl accident for the natural and human environments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dreicer, M.; Aarkog, A.; Alexakhin, R.

    1996-07-01

    In the ten years since the Chernobyl accident, an enormous amount of work has been done to assess the consequences to the natural and human environment. Although it is difficult to summarize such a large and varied field, some general conclusions can be drawn. This background paper includes the main findings concerning the direct impacts of radiation on the flora and fauna; the general advances of knowledge in the cycling of radionuclides in natural, seminatural and agricultural environments; some evaluation of countermeasures that were used; and a summary of the human radiation doses resulting from the environmental contamination. although openmore » questions still remain, it can be concluded that: (1) at high radiation levels, the natural environment has shown short term impacts but any significant long term impacts remain to be seen; (2) effective countermeasures can be taken to reduce the transfer of contamination from the environment to humans but these are highly site specific and must be evaluated in terms of practicality as well as population does reduction; (3) the majority of the doses have already been received by the human population. If agricultural countermeasures are appropriately taken, the main source of future doses will be the gathering of food and recreational activities in natural and seminatural ecosystems.« less

  15. Influence of radiation dose and reconstruction algorithm in MDCT assessment of airway wall thickness: A phantom study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gomez-Cardona, Daniel; Nagle, Scott K.; Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53792

    Purpose: Wall thickness (WT) is an airway feature of great interest for the assessment of morphological changes in the lung parenchyma. Multidetector computed tomography (MDCT) has recently been used to evaluate airway WT, but the potential risk of radiation-induced carcinogenesis—particularly in younger patients—might limit a wider use of this imaging method in clinical practice. The recent commercial implementation of the statistical model-based iterative reconstruction (MBIR) algorithm, instead of the conventional filtered back projection (FBP) algorithm, has enabled considerable radiation dose reduction in many other clinical applications of MDCT. The purpose of this work was to study the impact of radiationmore » dose and MBIR in the MDCT assessment of airway WT. Methods: An airway phantom was scanned using a clinical MDCT system (Discovery CT750 HD, GE Healthcare) at 4 kV levels and 5 mAs levels. Both FBP and a commercial implementation of MBIR (Veo{sup TM}, GE Healthcare) were used to reconstruct CT images of the airways. For each kV–mAs combination and each reconstruction algorithm, the contrast-to-noise ratio (CNR) of the airways was measured, and the WT of each airway was measured and compared with the nominal value; the relative bias and the angular standard deviation in the measured WT were calculated. For each airway and reconstruction algorithm, the overall performance of WT quantification across all of the 20 kV–mAs combinations was quantified by the sum of squares (SSQs) of the difference between the measured and nominal WT values. Finally, the particular kV–mAs combination and reconstruction algorithm that minimized radiation dose while still achieving a reference WT quantification accuracy level was chosen as the optimal acquisition and reconstruction settings. Results: The wall thicknesses of seven airways of different sizes were analyzed in the study. Compared with FBP, MBIR improved the CNR of the airways, particularly at low

  16. Empirical evaluation of sufficient similarity in dose-response for environmental risk assessment of a mixture of 11 pyrethroids.

    EPA Science Inventory

    Chemical mixtures in the environment are often the result of a dynamic process. When dose-response data are available on random samples throughout the process, equivalence testing can be used to determine whether the mixtures are sufficiently similar based on a pre-specified biol...

  17. Development of pig welfare assessment protocol integrating animal-, environment-, and management-based measures.

    PubMed

    Renggaman, Anriansyah; Choi, Hong L; Sudiarto, Sartika Ia; Alasaarela, Laura; Nam, Ok S

    2015-01-01

    Due to increased interest in animal welfare, there is now a need for a comprehensive assessment protocol to be used in intensive pig farming systems. There are two current welfare assessment protocols for pigs: Welfare Quality® Assessment Protocols (applicable in the Europe Union), that mostly focuses on animal-based measures, and the Swine Welfare Assurance Program (applicable in the United States), that mostly focuses on management- and environment-based measures. In certain cases, however, animal-based measures might not be adequate for properly assessing pig welfare status. Similarly, welfare assessment that relies only on environment- and management-based measures might not represent the actual welfare status of pigs. Therefore, the objective of this paper was to develop a new welfare protocol by integrating animal-, environment-, and management-based measures. The background for selection of certain welfare criteria and modification of the scoring systems from existing welfare assessment protocols are described. The developed pig welfare assessment protocol consists of 17 criteria that are related to four main principles of welfare (good feeding, good housing, good health, and appropriate behavior). Good feeding, good housing, and good health were assessed using a 3-point scale: 0 (good welfare), 1 (moderate welfare), and 2 (poor welfare). In certain cases, only a 2-point scale was used: 0 (certain condition is present) or 2 (certain condition is absent). Appropriate behavior was assessed by scan sampling of positive and negative social behaviors based on qualitative behavior assessment and human-animal relationship tests. Modification of the body condition score into a 3-point scale revealed pigs with a moderate body condition (score 1). Moreover, additional criteria such as feed quality confirmed that farms had moderate (score 1) or poor feed quality (score 2), especially those farms located in a high relative humidity region. The developed protocol can be

  18. Fractal Risk Assessment of ISS Propulsion Module in Meteoroid and Orbital Debris Environments

    NASA Technical Reports Server (NTRS)

    Mog, Robert A.

    2001-01-01

    A unique and innovative risk assessment of the International Space Station (ISS) Propulsion Module is conducted using fractal modeling of the Module's response to the meteoroid and orbital debris environments. Both the environment models and structural failure modes due to the resultant hypervelocity impact phenomenology, as well as Module geometry, are investigated for fractal applicability. The fractal risk assessment methodology could produce a greatly simplified alternative to current methodologies, such as BUMPER analyses, while maintaining or increasing the number of complex scenarios that can be assessed. As a minimum, this innovative fractal approach will provide an independent assessment of existing methodologies in a unique way.

  19. Biointerfaces for Two-way Communication to Assess Hazards in the Aquatic Environment.

    DTIC Science & Technology

    1999-11-01

    to provide timely information on contaminants in freshwater and marine environments. 14. SUBJECT TERMS 15. NUMBER OF PAGES Sentinel species, aquatic ...for using aquatic organisms to provide timely information on contaminants in freshwater and marine environments. Some of the research challenges that...Technical Report 0001 Biointerfaces for Two-way Communication to Assess Hazards in the Aquatic Environment U.S. Army Center for Environmental Health

  20. 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.

  1. Radiotherapy for glioma during pregnancy: fetal dose estimates, risk assessment and clinical management.

    PubMed

    Haba, Y; Twyman, N; Thomas, S J; Overton, C; Dendy, P; Burnet, N G

    2004-05-01

    Cancer in pregnancy is relatively uncommon, but constitutes a major problem. We report the measurement of scatter dose to the fetus and the estimated fetal risk from that exposure in an illustrative case of a patient, 20 weeks pregnant, with a grade 3 anaplastic astrocytoma. A clinical decision was made to withhold radiotherapy, if possible, until after delivery. Sequential magnetic resonance imaging (MRI) showed no progression during the pregnancy. In the event, she was managed conservatively until the successful completion of her pregnancy. In case radiotherapy was required, an estimation of the fetal risk was made. Phantom measurements were undertaken to assess the likely fetal dose. Film badges were used to estimate the scattered radiation energy. Measurements were made on a Varian 600C at 6 MV and Asea Brown Boveri (ABB) accelerator at 8 and 16 MV. Doses were measured at 30, 45 and 60 cm from the isocentre; the fetus was assumed to lie at about 60 cm and not closer than 45 cm from the isocentre. Estimated doses to the position of the fetus were lowest with the 6 MV Varian accelerator. Using this machine without additional abdominal shielding, the estimated dose on the surface at 45 cm from the tumour volume was 2.2 cGy for a tumour dose of 54 Gy; using the ABB accelerator, the dose varied between 49-59 cGy. The energy of scattered radiation was in the range 208-688 keV, so that additional shielding would be practical to further reduce the fetal dose. The risk of cancer up to the age of 15 years attributable to radiation is 1 in 1700 per cGy, of which half will be fatal (i.e. 1 in 3300 per cGy). A dose of 2.2 cGy adds a risk of fatal cancer by the age 15 years of only 1 in 1500. Because the addition of shielding might halve the fetal dose, this risk should be reduced to 1 in 3000. For comparison, the overall UK risk of cancer up to the age 15 years is 1 in 650. In conclusion, careful choice of linear accelerator for the treatment of a pregnant woman and the use

  2. Recent developments in human biomonitoring: non-invasive assessment of target tissue dose and effects of pneumotoxic metals.

    PubMed

    Mutti, A; Corradi, M

    2006-01-01

    Tobacco smoke and polluted environments substantially increase the lung burden of pneumotoxic chemicals, particularly pneumotoxic metallic elements. To achieve a better understanding of the early events between exposure to inhaled toxicants and the onset of adverse effects on the lung, the characterization of dose at the target organ would be extremely useful. Exhaled breath condensate (EBC), obtained by cooling exhaled air under conditions of spontaneous breathing, is a novel technique that could provide a non-invasive assessment of pulmonary pathobiology. Considering that EBC is water practically free of interfering solutes, it represents an ideal biological matrix for elemental characterization. Published data show that several toxic metals and trace elements are detectable in EBC, raising the possibility of using this medium to quantify the lung tissue dose of pneumotoxic substances. This novel approach may represent a significant advance over the analysis of alternative media (blood, serum, urine, hair), which are not as reliable (owing to interfering substances in the complex matrix) and reflect systemic rather than lung (target tissue) levels of both toxic metals and essential trace elements. Data obtained among workers occupationally exposed to either hard metals or chromium (VI) and in smokers with or without chronic obstructive pulmonary disease (COPD) are reviewed to show that--together with biomarkers of exposure--EBC also allows the simultaneous quantification of biomarkers of effect directly sampled from the epithelial lining fluid, thus providing novel insights on both kinetic and dynamic aspects of metal toxicology.

  3. 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...

  4. 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...

  5. Organ Dose Assessment and Evaluation of Cancer Risk on Mars Surface

    NASA Technical Reports Server (NTRS)

    Kim, Myung-Hee; Cucinotta, Francis A.

    2011-01-01

    Organ specific fluence spectra and doses for large solar particle events (SPE) and galactic cosmic rays (GCR) at various levels of solar activity are simulated on the surface of Mars using the HZETRN/QMSFRG computer code and the 2010 version of the Badhwar and O Neill GCR model. The NASA JSC propensity model of SPE fluence and occurrence is used to consider upper bounds on SPE fluence for increasing mission lengths. To account for the radiation transmission through the Mars atmosphere, a vertical distribution of Mars atmospheric thickness is calculated from the temperature and pressure data of Mars Global Surveyor. To describe the spherically distributed atmospheric distance on the Mars surface at each elevation, the directional cosine distribution is implemented. The resultant directional shielding by Mars atmosphere at each elevation is then coupled with vehicle and body shielding for organ dose estimates. Finally, cancer risks for astronauts exploring Mars can be assessed by applying the NASA Space Radiation Cancer Risk 2010 model with the resultant organ dose estimates. Variations of organ doses and cancer risk quantities on the surface of Mars, which are due to a 16-km elevation range between the Tharsis Montes and the Hellas impact basin, are visualized on the global topography of Mars measured by the Mars Orbiter Laser Altimeter. It is found that cancer incidence risks are about 2-fold higher than mortality risks with a disproportionate increase in skin and thyroid cancers for male and female astronauts and in breast cancer for female astronauts. The number of safe days, defined by the upper 95% percent confidence level to be below cancer limits, on Mars is analyzed for several Mars mission design scenarios.

  6. Scale Development of a Measure to Assess Community-Based and Clinical Intervention Group Environments

    ERIC Educational Resources Information Center

    Wilson, Patrick A.; Hansen, Nathan B.; Tarakeshwar, Nalini; Neufeld, Sharon; Kochman, Arlene; Sikkema, Kathleen J.

    2008-01-01

    Though group interventions are widely used in community-based and clinical settings, there are few brief instruments for assessing the group environment. Two studies on the development of a brief measure to assess intervention group environments are described, and psychometric properties of the new scale are presented. The new measure is based on…

  7. Assessment of ultrafine particles in Portuguese preschools: levels and exposure doses.

    PubMed

    Fonseca, J; Slezakova, K; Morais, S; Pereira, M C

    2014-12-01

    The aim of this work was to assess ultrafine particles (UFP) number concentrations in different microenvironments of Portuguese preschools and to estimate the respective exposure doses of UFP for 3-5-year-old children (in comparison with adults). UFP were sampled both indoors and outdoors in two urban (US1, US2) and one rural (RS1) preschool located in north of Portugal for 31 days. Total levels of indoor UFP were significantly higher at the urban preschools (mean of 1.82 × 10(4) and 1.32 × 10(4) particles/cm(3) at US1 an US2, respectively) than at the rural one (1.15 × 10(4) particles/cm(3) ). Canteens were the indoor microenvironment with the highest UFP (mean of 5.17 × 10(4) , 3.28 × 10(4) , and 4.09 × 10(4) particles/cm(3) at US1, US2, and RS1), whereas the lowest concentrations were observed in classrooms (9.31 × 10(3) , 11.3 × 10(3) , and 7.14 × 10(3) particles/cm(3) at US1, US2, and RS1). Mean indoor/outdoor ratios (I/O) of UFP at three preschools were lower than 1 (0.54-0.93), indicating that outdoor emissions significantly contributed to UFP indoors. Significant correlations were obtained between temperature, wind speed, relative humidity, solar radiation, and ambient UFP number concentrations. The estimated exposure doses were higher in children attending urban preschools; 3-5-year-old children were exposed to 4-6 times higher UFP doses than adults with similar daily schedules. This study reports information on ultrafine particles (UFPs) in various indoor and outdoor microenvironments (canteens, classrooms, gymnasiums, and outdoor) of urban and rural preschools. It identifies the potential sources and origins, characterizes the influence of meteorological parameters on UFP levels, and performs a comparison with other existing international studies. To this date, relatively few studies have investigated UFP in preschools (none in Portugal) and none assessed exposure dose for different age-groups. The obtained findings showed that levels of UFP in

  8. Personnel Dose Assessment during Active Interrogation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    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 dosemore » 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.« less

  9. MODEL DEVELOPMENT AND APPLICATION FOR ASSESSING HUMAN EXPOSURE AND DOSE TO TOXIC CHEMICALS AND POLLUTANTS

    EPA Science Inventory

    This project aims to strengthen the general scientific foundation of EPA's exposure and risk assessment processes by developing state-of-the-art exposure to dose computational models. This research will produce physiologically-based pharmacokinetic (PBPK) and pharmacodynamic (PD)...

  10. A biosphere modeling methodology for dose assessments of the potential Yucca Mountain deep geological high level radioactive waste repository.

    PubMed

    Watkins, B M; Smith, G M; Little, R H; Kessler, J

    1999-04-01

    Recent developments in performance standards for proposed high level radioactive waste disposal at Yucca Mountain suggest that health risk or dose rate limits will likely be part of future standards. Approaches to the development of biosphere modeling and dose assessments for Yucca Mountain have been relatively lacking in previous performance assessments due to the absence of such a requirement. This paper describes a practical methodology used to develop a biosphere model appropriate for calculating doses from use of well water by hypothetical individuals due to discharges of contaminated groundwater into a deep well. The biosphere model methodology, developed in parallel with the BIOMOVS II international study, allows a transparent recording of the decisions at each step, from the specification of the biosphere assessment context through to model development and analysis of results. A list of features, events, and processes relevant to Yucca Mountain was recorded and an interaction matrix developed to help identify relationships between them. Special consideration was given to critical/potential exposure group issues and approaches. The conceptual model of the biosphere system was then developed, based on the interaction matrix, to show how radionuclides migrate and accumulate in the biosphere media and result in potential exposure pathways. A mathematical dose assessment model was specified using the flexible AMBER software application, which allows users to construct their own compartment models. The starting point for the biosphere calculations was a unit flux of each radionuclide from the groundwater in the geosphere into the drinking water in the well. For each of the 26 radionuclides considered, the most significant exposure pathways for hypothetical individuals were identified. For 14 of the radionuclides, the primary exposure pathways were identified as consumption of various crops and animal products following assumed agricultural use of the contaminated

  11. Assessment of the benefits and impacts in the U.S. Nuclear Power Industry of hypothesized lower occupational dose limits

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Andersen, R.L.; Schmitt, J.F.

    1995-03-01

    The International Commission on Radiological Protection and the National Council on Radiation Protection and Measurements have issued recommendations that would limit occupational exposure of individuals to doses lower than regulatory limits contained in the Nuclear Regulatory Commission`s 10 CFR Part 20, {open_quotes}Standards for Protection Against Radiation{close_quotes}. Because of this situation, there is interest in the potential benefits and impacts that would be associated with movement of the NRC regulatory limits toward the advisory bodies recommendations. The records of occupational worker doses in the U.S. commercial nuclear power industry show that the vast majority of these workers have doses that aremore » significantly below the regulatory limit of 50 mSv (5 rem) per year. Some workers doses do approach the limits, however. This is most common in the case of specially skilled workers, especially those with skills utilized in support of plant outage work. Any consideration of the potential benefits and impacts of hypothesized lower dose limits must address these workers as an important input to the overall assessment. There are also, of course, many other areas in which the benefits and impacts must be evaluated. To prepare to provide valid, constructive input on this matter, the U.S. nuclear power industry is undertaking an assessment, facilitated by the Nuclear Energy Institute (NEI), of the potential benefits and impacts at its facilities associated with hypothesized lower occupational dose limits. Some preliminary results available to date from this assessment are provided.« less

  12. Neck pain assessment in a virtual environment.

    PubMed

    Sarig-Bahat, Hilla; Weiss, Patrice L Tamar; Laufer, Yocheved

    2010-02-15

    Neck-pain and control group comparative analysis of conventional and virtual reality (VR)-based assessment of cervical range of motion (CROM). To use a tracker-based VR system to compare CROM of individuals suffering from chronic neck pain with CROM of asymptomatic individuals; to compare VR system results with those obtained during conventional assessment; to present the diagnostic value of CROM measures obtained by both assessments; and to demonstrate the effect of a single VR session on CROM. Neck pain is a common musculoskeletal complaint with a reported annual prevalence of 30% to 50%. In the absence of a gold standard for CROM assessment, a variety of assessment devices and methodologies exist. Common to these methodologies, assessment of CROM is carried out by instructing subjects to move their head as far as possible. However, these elicited movements do not necessarily replicate functional movements which occur spontaneously in response to multiple stimuli. To achieve a more functional approach to cervical motion assessment, we have recently developed a VR environment in which electromagnetic tracking is used to monitor cervical motion while participants are involved in a simple yet engaging gaming scenario. CROM measures were collected from 25 symptomatic and 42 asymptomatic individuals using VR and conventional assessments. Analysis of variance was used to determine differences between groups and assessment methods. Logistic regression analysis, using a single predictor, compared the diagnostic ability of both methods. Results obtained by both methods demonstrated significant CROM limitations in the symptomatic group. The VR measures showed greater CROM and sensitivity while conventional measures showed greater specificity. A single session exposure to VR resulted in a significant increase in CROM. Neck pain is significantly associated with reduced CROM as demonstrated by both VR and conventional assessment methods. The VR method provides assessment of

  13. 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.

  14. Ten Thousand Years of Environment Assessment Using Synchrotron Radiation Micro Beam

    NASA Astrophysics Data System (ADS)

    Shirasawa, K.; Ide-Ektessabi, A.; Koizumi, A.; Azechi, M.

    2003-08-01

    The environment surrounding human has changed through civilization and industrialization, and through these developments, problems including the pollution from heavy metals such as lead and mercury have arisen. In this study, we analyzed major and trace elements in modern and prehistoric teeth by x-ray fluorescence (XRF) analysis using synchrotron radiation micro beam, in order to assess the changes of the environment through the civilization and the industrialization and their affects to the human. It is suggested that teeth accumulate elements in the mineral phase, hydroxiapatite, during their formation, and because there are no significant turnovers, teeth are concerned to be indicators of the environment of the donor. We first analyzed the elements on the surface of tooth from modern individual and tooth from human remains of Jomon period to assess the heavy metal concentration and effect of the diagenesis. The adhering ground elements on the prehistoric teeth showed high amount of Ti, Fe, Mn and other metallic elements.

  15. Design and assessment of a robust voltage amplifier with 2.5 GHz GBW and >100 kGy total dose tolerance

    NASA Astrophysics Data System (ADS)

    Verbeeck, J.; Leroux, P.; Steyaert, M.

    2011-01-01

    A differential voltage amplifier with a gain-bandwidth product of 2.5Ghz and using adaptive biasing has been designed in a standard CMOS technology and assessed under radiation and temperature variations. The principle used in this ASIC will be employed in the design of a Gbps TIA with improved tolerance for γ-irradiation and temperature for an optical instrumentation (LIDAR) receiver aiming at operation in harsh environments. The voltage amplifier was tested under gamma radiation and features a gain degradation of merely 4.5% up to a total dose of 100kGy. In order to verify the radiation effects on the IC, the threshold voltage shift of the separate transistors has been investigated. Temperature characterization has shown that the amplifier features a reduction of the voltage gain by only 5.6% for a temperature range of -40 till 130 °C.

  16. Assessment of the work environment of faculty of a Medical College in Pakistan.

    PubMed

    Saeed, Abid; Butt, Zahid Ahmad

    2014-01-01

    Extensive research is done on nursing work environments but less is known about the job conditions and environments of other health professionals. This study was aimed to fill this information gap by highlighting the factors affecting the work environment and stressors causing turnover of staff. A cross sectional study was conducted in Bolan Medical College Quetta for the assessment of working environment of the faculty from 22nd April to 22nd July 2012. All permanent teaching staff was included. A structured questionnaire was adopted fromI health sciences association of Alberta (HSSA), 2006 work Environment Survey. An observational check list for assessment of the physical environment /infrastructure and other general physical stuff was used. The faculty menibers were-not-satisfied with the security and safety of their work place but were satisfied with salaries, employer, and management. Work teams and relationship between employees and employers were respectful with good communication. Majority found their work times stressful and opportunities for on job trainings and professional development, adequate tools, equipment and conditions were mostly lacking. The overall working environment is not that good and few areas need serious attention like: professional development, trainings, adequate equipment, and security.

  17. Atmospheric radiation flight dose rates

    NASA Astrophysics Data System (ADS)

    Tobiska, W. K.

    2015-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has been conducting space weather observations of the atmospheric radiation environment at aviation altitudes that will eventually be transitioned into air traffic management operations. The Automated Radiation Measurements for Aerospace Safety (ARMAS) system and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) both are providing dose rate measurements. Both activities are under the ARMAS goal of providing the "weather" of the radiation environment to improve aircraft crew and passenger safety. Over 5-dozen ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. Flight altitudes now exceed 60,000 ft. and extend above commercial aviation altitudes into the stratosphere. In this presentation we describe recent ARMAS and USEWX results.

  18. Dose assessment for various coals in the coal-fired power plant

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Antic, D.; Sokcic-Kostic, M.

    1993-01-01

    The radiation exposure of the public in the vicinity of a coal-fired power plant has been studied. The experimental data on uranium, thorium, and potassium content in selected coals from Serbia and Bosnia have been used to calculate the release rates of natural radionuclides from the power plant. A generalized model for analysis of radiological impact of an energy source that includes the two-dimensional version of the cloud model simulates the transport of radionuclides released to the atmosphere. The inhalation dose rates are assessed for various meteorological conditions.

  19. Dose response explorer: an integrated open-source tool for exploring and modelling radiotherapy dose volume outcome relationships

    NASA Astrophysics Data System (ADS)

    El Naqa, I.; Suneja, G.; Lindsay, P. E.; Hope, A. J.; Alaly, J. R.; Vicic, M.; Bradley, J. D.; Apte, A.; Deasy, J. O.

    2006-11-01

    Radiotherapy treatment outcome models are a complicated function of treatment, clinical and biological factors. Our objective is to provide clinicians and scientists with an accurate, flexible and user-friendly software tool to explore radiotherapy outcomes data and build statistical tumour control or normal tissue complications models. The software tool, called the dose response explorer system (DREES), is based on Matlab, and uses a named-field structure array data type. DREES/Matlab in combination with another open-source tool (CERR) provides an environment for analysing treatment outcomes. DREES provides many radiotherapy outcome modelling features, including (1) fitting of analytical normal tissue complication probability (NTCP) and tumour control probability (TCP) models, (2) combined modelling of multiple dose-volume variables (e.g., mean dose, max dose, etc) and clinical factors (age, gender, stage, etc) using multi-term regression modelling, (3) manual or automated selection of logistic or actuarial model variables using bootstrap statistical resampling, (4) estimation of uncertainty in model parameters, (5) performance assessment of univariate and multivariate analyses using Spearman's rank correlation and chi-square statistics, boxplots, nomograms, Kaplan-Meier survival plots, and receiver operating characteristics curves, and (6) graphical capabilities to visualize NTCP or TCP prediction versus selected variable models using various plots. DREES provides clinical researchers with a tool customized for radiotherapy outcome modelling. DREES is freely distributed. We expect to continue developing DREES based on user feedback.

  20. Flight attendant radiation dose from solar particle events.

    PubMed

    Anderson, Jeri L; Mertens, Christopher J; Grajewski, Barbara; Luo, Lian; Tseng, Chih-Yu; Cassinelli, Rick T

    2014-08-01

    Research has suggested that work as a flight attendant may be related to increased risk for reproductive health effects. Air cabin exposures that may influence reproductive health include radiation dose from galactic cosmic radiation and solar particle events. This paper describes the assessment of radiation dose accrued during solar particle events as part of a reproductive health study of flight attendants. Solar storm data were obtained from the National Oceanic and Atmospheric Administration Space Weather Prediction Center list of solar proton events affecting the Earth environment to ascertain storms relevant to the two study periods (1992-1996 and 1999-2001). Radiation dose from exposure to solar energetic particles was estimated using the NAIRAS model in conjunction with galactic cosmic radiation dose calculated using the CARI-6P computer program. Seven solar particle events were determined to have potential for significant radiation exposure, two in the first study period and five in the second study period, and over-lapped with 24,807 flight segments. Absorbed (and effective) flight segment doses averaged 6.5 μGy (18 μSv) and 3.1 μGy (8.3 μSv) for the first and second study periods, respectively. Maximum doses were as high as 440 μGy (1.2 mSv) and 20 flight segments had doses greater than 190 μGy (0.5 mSv). During solar particle events, a pregnant flight attendant could potentially exceed the equivalent dose limit to the conceptus of 0.5 mSv in a month recommended by the National Council on Radiation Protection and Measurements.

  1. Monte Carlo Assessments of Absorbed Doses to the Hands of Radiopharmaceutical Workers Due to Photon Emitters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

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

    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 weremore » 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.« less

  2. Assessment of Ablative Therapies in Swine: Response of Respiratory Diaphragm to Varying Doses.

    PubMed

    Singal, Ashish; Mattison, Lars M; Soule, Charles L; Ballard, John R; Rudie, Eric N; Cressman, Erik N K; Iaizzo, Paul A

    2018-03-28

    Ablation is a common procedure for treating patients with cancer, cardiac arrhythmia, and other conditions, yet it can cause collateral injury to the respiratory diaphragm. Collateral injury can alter the diaphragm's properties and/or lead to respiratory dysfunction. Thus, it is important to understand the diaphragm's physiologic and biomechanical properties in response to ablation therapies, in order to better understand ablative modalities, minimize complications, and maximize the safety and efficacy of ablative procedures. In this study, we analyzed physiologic and biomechanical properties of swine respiratory diaphragm muscle bundles when exposed to 5 ablative modalities. To assess physiologic properties, we performed in vitro tissue bath studies and measured changes in peak force and baseline force. To assess biomechanical properties, we performed uniaxial stress tests, measuring force-displacement responses, stress-strain characteristics, and avulsion forces. After treating the muscle bundles with all 5 ablative modalities, we observed dose-dependent sustained reductions in peak force and transient increases in baseline force-but no consistent dose-dependent biomechanical responses. These data provide novel insights into the effects of various ablative modalities on the respiratory diaphragm, insights that could enable improvements in ablative techniques and therapies.

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

    PubMed

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

    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.

  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. Assessment of dose rate to terrestrial biota in the area around coal fired power plant applying ERICA tool and RESRAD BIOTA code.

    PubMed

    Ćujić, Mirjana; Dragović, Snežana

    2018-08-01

    This paper presents the environmental radiation risk assessment based on two software program approaches ERICA Tool (version 1.2) and RESRAD BIOTA (version 1.5) to estimate dose rates to terrestrial biota in the area around the largest coal fired power plant in Serbia. For dose rate assessment software's default reference animals and plants and the best estimated values of activity concentrations of 238 U, 234 U, 234 Th, 232 Th, 230 Th, 226 Ra, 210 Pb, 210 Po, 137 Cs in soil were used. Both approaches revealed the highest contribution to the internal dose rate due to 226 Ra and 210 Po, while 137 Cs contributed the most to the external dose rate. In the investigated area total dose rate to biota derived using ERICA Tool ranged from 0.3 to 14.4 μGy h -1 . The natural radionuclides exhibited significantly higher contribution to the total dose rate than the artificial one. In the investigated area, only dose rate for lichens and bryophytes exceeded ERICA Tool screening value of total dose rate of 10 μGy h -1 suggested as confident that environmental risks are negligible. The assessed total dose rates for reference animals and plants using RESRAD BIOTA were found to be 7 and 3 μGy h -1 , respectively. In RESRAD BIOTA - Level 3, 10 species (Lumbricus terrestris, Rana lessonae, Sciurus vulgaris, Anas platyrhynchos, Lepus europaeus, Vulpes vulpes, Capreolus capreolus, Suss crofa, Quercu srobur, Tilia spp.) representative for the study area were modeled. Among them the highest total dose rate (4.5 μGy h -1 ) was obtained for large mammals. Differences in the predicted dose rates to biota using the two software programs are the consequence of the difference in the values of transfer parameters used to calculate activity concentrations in biota. Doses of ionizing radiation estimated in this study will not exhibit deterministic effects at the population level. Thus, the obtained results indicate no significant radiation impact of coal fired power plant operation on

  6. 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…

  7. Development of a Questionnaire Assessing School Physical Activity Environment

    ERIC Educational Resources Information Center

    Robertson-Wilson, Jennifer; Levesque, Lucie; Holden, Ronald R.

    2007-01-01

    This study was designed to develop the Questionnaire Assessing School Physical Activity Environment (Q--SPACE) based on student perceptions. Twenty-eight items rated on 4-point Likert scales were administered to 244 middle school students in 9 schools. Exploratory factor analysis was used to evaluate the underlying structure of the items and 2…

  8. A new assessment method for urbanization environmental impact: urban environment entropy model and its application.

    PubMed

    Ouyang, Tingping; Fu, Shuqing; Zhu, Zhaoyu; Kuang, Yaoqiu; Huang, Ningsheng; Wu, Zhifeng

    2008-11-01

    The thermodynamic law is one of the most widely used scientific principles. The comparability between the environmental impact of urbanization and the thermodynamic entropy was systematically analyzed. Consequently, the concept "Urban Environment Entropy" was brought forward and the "Urban Environment Entropy" model was established for urbanization environmental impact assessment in this study. The model was then utilized in a case study for the assessment of river water quality in the Pearl River Delta Economic Zone. The results indicated that the assessing results of the model are consistent to that of the equalized synthetic pollution index method. Therefore, it can be concluded that the Urban Environment Entropy model has high reliability and can be applied widely in urbanization environmental assessment research using many different environmental parameters.

  9. Personalized Assessment of kV Cone Beam Computed Tomography Doses in Image-guided Radiotherapy of Pediatric Cancer Patients

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang Yibao; Yan Yulong; Nath, Ravinder

    2012-08-01

    Purpose: To develop a quantitative method for the estimation of kV cone beam computed tomography (kVCBCT) doses in pediatric patients undergoing image-guided radiotherapy. Methods and Materials: Forty-two children were retrospectively analyzed in subgroups of different scanned regions: one group in the head-and-neck and the other group in the pelvis. Critical structures in planning CT images were delineated on an Eclipse treatment planning system before being converted into CT phantoms for Monte Carlo simulations. A benchmarked EGS4 Monte Carlo code was used to calculate three-dimensional dose distributions of kVCBCT scans with full-fan high-quality head or half-fan pelvis protocols predefined by themore » manufacturer. Based on planning CT images and structures exported in DICOM RT format, occipital-frontal circumferences (OFC) were calculated for head-and-neck patients using DICOMan software. Similarly, hip circumferences (HIP) were acquired for the pelvic group. Correlations between mean organ doses and age, weight, OFC, and HIP values were analyzed with SigmaPlot software suite, where regression performances were analyzed with relative dose differences (RDD) and coefficients of determination (R{sup 2}). Results: kVCBCT-contributed mean doses to all critical structures decreased monotonically with studied parameters, with a steeper decrease in the pelvis than in the head. Empirical functions have been developed for a dose estimation of the major organs at risk in the head and pelvis, respectively. If evaluated with physical parameters other than age, a mean RDD of up to 7.9% was observed for all the structures in our population of 42 patients. Conclusions: kVCBCT doses are highly correlated with patient size. According to this study, weight can be used as a primary index for dose assessment in both head and pelvis scans, while OFC and HIP may serve as secondary indices for dose estimation in corresponding regions. With the proposed empirical functions, it is

  10. Influence of dosemeter position for the assessment of eye lens dose during interventional cardiology.

    PubMed

    Principi, Sara; Ginjaume, Mercè; Duch, Maria Amor; Sánchez, Roberto M; Fernández, Jose M; Vano, Eliseo

    2015-04-01

    The equivalent dose limit for the eye lens for occupational exposure recommended by the ICRP has been reduced to 20 mSv y(-1) averaged over defined periods of 5 y, with no single year exceeding 50 mSv. The compliance with this new requirement could not be easy in some workplace such as interventional radiology and cardiology. The aim of this study is to evaluate different possible approaches in order to have a good estimate of the eye lens dose during interventional procedures. Measurements were performed with an X-ray system Philips Allura FD-10, using a PMMA phantom to simulate the patient scattered radiation and a Rando phantom to simulate the cardiologist. Thermoluminescence (TL) whole-body and TL eye lens dosemeters together with Philips DoseAware active dosemeters were located on different positions of the Rando phantom to estimate the eye lens dose in typical cardiology procedures. The results show that, for the studied conditions, any of the analysed dosemeter positions are suitable for eye lens dose assessment. However, the centre of the thyroid collar and the left ear position provide a better estimate. Furthermore, in practice, improper use of the ceiling-suspended screen can produce partial protection of some parts of the body, and thus large differences between the measured doses and the actual exposure of the eye could arise if the dosemeter is not situated close to the eye. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Practical applications of internal dose calculations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Carbaugh, E.H.

    1994-06-01

    Accurate estimates of intake magnitude and internal dose are the goal for any assessment of an actual intake of radioactivity. When only one datum is available on which to base estimates, the choices for internal dose assessment become straight-forward: apply the appropriate retention or excretion function, calculate the intake, and calculate the dose. The difficulty comes when multiple data and different types of data become available. Then practical decisions must be made on how to interpret conflicting data, or how to adjust the assumptions and techniques underlying internal dose assessments to give results consistent with the data. This article describesmore » nine types of adjustments which can be incorporated into calculations of intake and internal dose, and then offers several practical insights to dealing with some real-world internal dose puzzles.« less

  12. 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...

  13. MODELS AND MODELING METHODS FOR ASSESSING HUMAN EXPOSURE AND DOSE TO TOXIC CHEMICALS AND POLLUTANTS

    EPA Science Inventory

    This project aims to strengthen the general scientific foundation of EPA's exposure and risk assessment, management, and policy processes by developing state-of-the-art exposure to dose mathematical models and solution methods. The results of this research will be to produce a mo...

  14. Quality Of Educational Environment At Wah Medical College: Assessment By Using Dundee Ready Educational Environment Measure.

    PubMed

    Mushtaq, Robina; Ansar, Ambreen; Bibi, Anwar; Ramzan, Musarat; Munir, Arif; Zaheer, Amna; Ahmad, Afsa; Barlas, Aisha

    2017-01-01

    Educational environment not only has an impact on the students during the academic years but has its reflections throughout their medical career. The Dundee Ready Educational Environment Measure (DREEM) is an internationally accepted useful tool to analyse undergraduate educational environments in the health professionals. The purpose of this study was to assess how students, across all the five years in a private medical college, perceive their educational environment. It was a cross sectional study, which used the DREEM inventory at Wah Medical College over the course of 6 months (January-June 2015). All 500 students were included in the study. The fifty items DREEM inventory, having the maximum score of two hundred indicating ideal educational environment was used for data collection. The questionnaire was completed by 400 undergraduate medical students (response rate 80%). The overall DREEM score was 122.63/200 (61.3%), indicating that the perception of the learning environment was more positive than negative. Among the highest scoring categories were students' participation in classes, relaxed atmosphere and confidence in passing the annual exams. However, many areas requiring improvement were also brought to attention. Overall, the student's perception of their learning environment at Wah Medical College was found to be positive. This study did bring to light some areas that could be improved upon. This should enable the faculty to adopt changes in their teaching methods to make the learning process more productive and enjoyable for future students.

  15. Further assessment of the clinically effective dose range of etoricoxib: a randomized, double-blinded, placebo-controlled trial in rheumatoid arthritis.

    PubMed

    Greenwald, M; Peloso, P M; Mandel, D; Soto, O; Mehta, A; Frontera, N; Boice, J A; Zhan, X J; Curtis, S P

    2011-10-01

    To further assess the clinically active dose range of etoricoxib, a COX-2 selective inhibitor, in rheumatoid arthritis (RA). RA patients were randomized to etoricoxib 10, 30, 60, or 90 mg or placebo in a double-blind, 12-week study. DMARDs (methotrexate, biologics) or low-dose corticosteroids were allowed in stable doses. The primary endpoint was the proportion of patients completing the study and achieving an American College of Rheumatology 20% (ACR20) response. Secondary endpoints included individual components of the ACR index and Patient Global Assessment of Pain. Safety was assessed by physical exam and adverse experiences (AEs) occurrences. Etoricoxib 90 mg was the only dose to reach a statistically significant difference from placebo (p < 0.001) on the primary endpoint; etoricoxib 60 mg approached significance (p = 0.057). Significant pain improvement vs. placebo was observed with etoricoxib 90 mg (p < 0.001), 60 mg (p = 0.018), and 30 mg (p = 0.017). Despite the use of background biologics and corticosteroids, a dose response was still apparent. A higher proportion of etoricoxib 60 and 90 mg patients had renovascular AEs (i.e., edema and hypertension) compared with placebo, although discontinuations for renovascular AEs were rare. Etoricoxib 90 mg had a higher incidence of serious AEs (n = 5; 1 was considered drug-related) versus placebo (n = 0). The present study was not powered to detect differences in cardiovascular or gastrointestinal safety by dose. Additionally, further research is needed to clarify the role of doses less than the etoricoxib 90 mg dose for pain management in RA patients. Etoricoxib 90 mg demonstrated statistically superior efficacy (ACR20) compared with placebo and numerical superiority over the other doses of etoricoxib studied. Etoricoxib 30 and 60 mg demonstrated significant pain improvement versus placebo, suggesting utility for some patients.

  16. Dose-response behavior of the bacterium Vibrio fischeri exposed to pharmaceuticals and personal care products.

    PubMed

    Ortiz de García, Sheyla; García-Encina, Pedro A; Irusta-Mata, Rubén

    2016-01-01

    The presence of pharmaceuticals and personal care products (PPCPs) in the environment has become a real and widespread concern in recent years. Therefore, the primary goal of this study was to investigate 20 common and widely used PPCPs to assess their individual and combined effect on an important species in one trophic level, i.e., bacteria. The ecotoxicological effects of PPCPs at two different concentration ranges were determined in the bacterium Vibrio fischeri using Microtox(®) and were statistically analyzed using three models in the GraphPad Prism 6 program for Windows, v.6.03. A four-parameter model best fit the majority of the compounds. The half maximal effective concentration (EC50) of each PPCP was estimated using the best-fitting model and was compared with the results from a recent study. Comparative analysis indicated that most compounds showed the same level of toxicity. Moreover, the stimulatory effects of PPCPs at environmental concentrations (low doses) were assessed. These results indicated that certain compounds have traditional inverted U- or J-shaped dose-response curves, and 55% of them presented a stimulatory effect below the zero effect-concentration point. Effective concentrations of 0 (EC0), 5 (EC5) and 50% (EC50) were calculated for each PPCP as the ecotoxicological points. All compounds that presented narcosis as a mode of toxic action at high doses also exhibited stimulation at low concentrations. The maximum stimulatory effect of a mixture was higher than the highest stimulatory effect of each individually tested compound. Moreover, when the exposure time was increased, the hormetic effect decreased. Hormesis is being increasingly included in dose-response studies because this may have a harmful, beneficial or indifferent effect in an environment. Despite the results obtained in this research, further investigations need to be conducted to elucidate the behavior of PPCPs in aquatic environments.

  17. Environmental assessment of creosote-treated pilings in the marine environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Butala, J.H.; Webb, D.A.; Jop, K.M.

    1995-12-31

    A comprehensive ecological risk assessment was conducted to evaluate the environmental impact of creosote-treated pilings in the marine environment at Moss Landing Harbor, Moss Landing, California. Four areas of investigation comprising the risk assessment were (1) evaluation of environmental conditions around existing creosote-treated pilings (2) investigating effects related to restoration of pilings (3) assessing creosote migration into surrounding environment, one year after pile-driving and (4) confirmation of creosote toxicity in laboratory studies. Biological and chemical evaluation of the impact of creosote-treated pilings was conducted on surface sheen, water column and sediment samples collected at Moss Landing Harbor. Water samples (surfacemore » sheen, water column and sediment pore water) were evaluated using short-term chronic exposures with Mysidopsis bahia, while bulk sediment samples were evaluated with 10-day sediment toxicity tests with Ampelisca abdita. Samples of surface, column water and sediment were analyzed for the constituents of creosote by GC mass spectrometry. In addition, a sample of neat material used to preserve treated pilings represented a reference for the polyaromatic hydrocarbons. Verification of organism response and analyses of field collected samples was performed by conducting 10-day A. abdita sediment and 7-day M. bahia elutriate exposures with creosote applied to clean sediment collected at Moss Landing, Evaluations were also performed to determine the effects of photoinduced toxicity on test organisms exposed to PAHs. The biological and analytical results of the field and laboratory exposures are being used to evaluate and determine risk of creosote-treated pilings on the marine environment.« less

  18. Development of an instrument to measure medical students' perceptions of the assessment environment: initial validation.

    PubMed

    Sim, Joong Hiong; Tong, Wen Ting; Hong, Wei-Han; Vadivelu, Jamuna; Hassan, Hamimah

    2015-01-01

    Assessment environment, synonymous with climate or atmosphere, is multifaceted. Although there are valid and reliable instruments for measuring the educational environment, there is no validated instrument for measuring the assessment environment in medical programs. This study aimed to develop an instrument for measuring students' perceptions of the assessment environment in an undergraduate medical program and to examine the psychometric properties of the new instrument. The Assessment Environment Questionnaire (AEQ), a 40-item, four-point (1=Strongly Disagree to 4=Strongly Agree) Likert scale instrument designed by the authors, was administered to medical undergraduates from the authors' institution. The response rate was 626/794 (78.84%). To establish construct validity, exploratory factor analysis (EFA) with principal component analysis and varimax rotation was conducted. To examine the internal consistency reliability of the instrument, Cronbach's α was computed. Mean scores for the entire AEQ and for each factor/subscale were calculated. Mean AEQ scores of students from different academic years and sex were examined. Six hundred and eleven completed questionnaires were analysed. EFA extracted four factors: feedback mechanism (seven items), learning and performance (five items), information on assessment (five items), and assessment system/procedure (three items), which together explained 56.72% of the variance. Based on the four extracted factors/subscales, the AEQ was reduced to 20 items. Cronbach's α for the 20-item AEQ was 0.89, whereas Cronbach's α for the four factors/subscales ranged from 0.71 to 0.87. Mean score for the AEQ was 2.68/4.00. The factor/subscale of 'feedback mechanism' recorded the lowest mean (2.39/4.00), whereas the factor/subscale of 'assessment system/procedure' scored the highest mean (2.92/4.00). Significant differences were found among the AEQ scores of students from different academic years. The AEQ is a valid and reliable

  19. BENCHMARK DOSE TECHNICAL GUIDANCE DOCUMENT ...

    EPA Pesticide Factsheets

    The U.S. EPA conducts risk assessments for an array of health effects that may result from exposure to environmental agents, and that require an analysis of the relationship between exposure and health-related outcomes. The dose-response assessment is essentially a two-step process, the first being the definition of a point of departure (POD), and the second extrapolation from the POD to low environmentally-relevant exposure levels. The benchmark dose (BMD) approach provides a more quantitative alternative to the first step in the dose-response assessment than the current NOAEL/LOAEL process for noncancer health effects, and is similar to that for determining the POD proposed for cancer endpoints. As the Agency moves toward harmonization of approaches for human health risk assessment, the dichotomy between cancer and noncancer health effects is being replaced by consideration of mode of action and whether the effects of concern are likely to be linear or nonlinear at low doses. Thus, the purpose of this project is to provide guidance for the Agency and the outside community on the application of the BMD approach in determining the POD for all types of health effects data, whether a linear or nonlinear low dose extrapolation is used. A guidance document is being developed under the auspices of EPA's Risk Assessment Forum. The purpose of this project is to provide guidance for the Agency and the outside community on the application of the benchmark dose (BMD) appr

  20. Assessment of diurnal systemic dose of agrochemicals in regulatory toxicity testing--an integrated approach without additional animal use.

    PubMed

    Saghir, Shakil A; Bartels, Michael J; Rick, David L; McCoy, Alene T; Rasoulpour, Reza J; Ellis-Hutchings, Robert G; Sue Marty, M; Terry, Claire; Bailey, Jason P; Billington, Richard; Bus, James S

    2012-07-01

    Integrated toxicokinetics (TK) data provide information on the rate, extent and duration of systemic exposure across doses, species, strains, gender, and life stages within a toxicology program. While routine for pharmaceuticals, TK assessments of non-pharmaceuticals are still relatively rare, and have never before been included in a full range of guideline studies for a new agrochemical. In order to better understand the relationship between diurnal systemic dose (AUC(24h)) and toxicity of agrochemicals, TK analyses in the study animals is now included in all short- (excluding acute), medium- and long-term guideline mammalian toxicity studies including reproduction/developmental tests. This paper describes a detailed procedure for the implementation of TK in short-, medium- and long-term regulatory toxicity studies, without the use of satellite animals, conducted on three agrochemicals (X11422208, 2,4-D and X574175). In these studies, kinetically-derived maximum doses (KMD) from short-term studies instead of, or along with, maximum tolerated doses (MTD) were used for the selection of the high dose in subsequent longer-term studies. In addition to leveraging TK data to guide dose level selection, the integrated program was also used to select the most appropriate method of oral administration (i.e., gavage versus dietary) of test materials for rat and rabbit developmental toxicity studies. The integrated TK data obtained across toxicity studies (without the use of additional/satellite animals) provided data critical to understanding differences in response across doses, species, strains, sexes, and life stages. Such data should also be useful in mode of action studies and to improve human risk assessments. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Safety assessment on pedestrian crossing environments using MLS data.

    PubMed

    Soilán, Mario; Riveiro, Belén; Sánchez-Rodríguez, Ana; Arias, Pedro

    2018-02-01

    In the framework of infrastructure analysis and maintenance in an urban environment, it is important to address the safety of every road user. This paper presents a methodology for the evaluation of several safety indicators on pedestrian crossing environments using geometric and radiometric information extracted from 3D point clouds collected by a Mobile Mapping System (MMS). The methodology is divided in four main modules which analyze the accessibility of the crossing area, the presence of traffic lights and traffic signs, and the visibility between a driver and a pedestrian on the proximities of a pedestrian crossing. The outputs of the analysis are exported to a Geographic Information System (GIS) where they are visualized and can be further processed in the context of city management. The methodology has been tested on approximately 30 pedestrian crossings in cluttered urban environments of two different cities. Results show that MMS are a valid mean to assess the safety of a specific urban environment, regarding its geometric conditions. Remarkable results are presented on traffic light classification, with a global F-score close to 95%. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. "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.

  3. Space Radiation Organ Doses for Astronauts on Past and Future Missions

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.

    2007-01-01

    We review methods and data used for determining astronaut organ dose equivalents on past space missions including Apollo, Skylab, Space Shuttle, NASA-Mir, and International Space Station (ISS). Expectations for future lunar missions are also described. Physical measurements of space radiation include the absorbed dose, dose equivalent, and linear energy transfer (LET) spectra, or a related quantity, the lineal energy (y) spectra that is measured by a tissue equivalent proportional counter (TEPC). These data are used in conjunction with space radiation transport models to project organ specific doses used in cancer and other risk projection models. Biodosimetry data from Mir, STS, and ISS missions provide an alternative estimate of organ dose equivalents based on chromosome aberrations. The physical environments inside spacecraft are currently well understood with errors in organ dose projections estimated as less than plus or minus 15%, however understanding the biological risks from space radiation remains a difficult problem because of the many radiation types including protons, heavy ions, and secondary neutrons for which there are no human data to estimate risks. The accuracy of projections of organ dose equivalents described here must be supplemented with research on the health risks of space exposure to properly assess crew safety for exploration missions.

  4. Environmental radiology assessment in Lahad Datu, Sabah

    NASA Astrophysics Data System (ADS)

    Siti Fharhana, Yusof; Wan Muhamad Saridan, Wan Hassan; Ahmad Termizi, Ramli; Mohd Hilmi, Sahini; Mohammad Syazwan, Mohd Sanusi; Nor Afifah, Basri; Nor Zati Hani, Abu Hanifah

    2017-10-01

    Monitoring terrestial gamma radiation is crucial to prepare a baseline data for environmental radiological protection. Radiological research was carried out in Lahad Datu, Sabah to obtain the radioactivity status and terrestrial gamma radiation level in the area. We measure the terrestrial gamma radiation dose rates and analyse the radioactivity concentration of primordial radionuclides for radiological risk assessment. We identified that the annual estimation of dose effective for public is below the public dose limit, 1 mSv per year. Public and environment safety and health are remain secure. The obtained data and results can be used as reference for environmental radiology protection.

  5. ESCAPE: Eco-Behavioral System for Complex Assessments of Preschool Environments. Research Draft.

    ERIC Educational Resources Information Center

    Carta, Judith J.; And Others

    The manual details an observational code designed to track a child during an entire day in a preschool setting. The Eco-Behavioral System for Complex Assessments of Preschool Environments (ESCAPE) encompasses assessment of the following three major categories of variables with their respective subcategories: (1) ecological variables (designated…

  6. 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 Ltd. All rights reserved.

  7. 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

  8. 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.

  9. Stimulation of colonic motility by oral PEG electrolyte bowel preparation assessed by MRI: comparison of split vs single dose

    PubMed Central

    Marciani, L; Garsed, K C; Hoad, C L; Fields, A; Fordham, I; Pritchard, S E; Placidi, E; Murray, K; Chaddock, G; Costigan, C; Lam, C; Jalanka-Tuovinen, J; De Vos, W M; Gowland, P A; Spiller, R C

    2014-01-01

    Background Most methods of assessing colonic motility are poorly acceptable to patients. Magnetic resonance imaging (MRI) can monitor gastrointestinal motility and fluid distributions. We predicted that a dose of oral polyethylene glycol (PEG) and electrolyte solution would increase ileo-colonic inflow and stimulate colonic motility. We aimed to investigate the colonic response to distension by oral PEG electrolyte in healthy volunteers (HVs) and to evaluate the effect of single 2 L vs split (2 × 1 L) dosing. Methods Twelve HVs received a split dose (1 L the evening before and 1 L on the study day) and another 12 HVs a single dose (2 L on the main study day) of PEG electrolyte. They underwent MRI scans, completed symptom questionnaires, and provided stool samples. Outcomes included small bowel water content, ascending colon motility index, and regional colonic volumes. Key Results Small bowel water content increased fourfold from baseline after ingesting both split (p = 0.0010) and single dose (p = 0.0005). The total colonic volume increase from baseline was smaller for the split dose at 35 ± 8% than for the single dose at 102 ± 27%, p = 0.0332. The ascending colon motility index after treatment was twofold higher for the single dose group (p = 0.0103). Conclusions & Inferences Ingestion of 1 and 2 L PEG electrolyte solution caused a rapid increase in the small bowel and colonic volumes and a robust rise in colonic motility. The increase in both volumes and motility was dose dependent. Such a challenge, being well-tolerated, could be a useful way of assessing colonic motility in future studies. PMID:25060551

  10. Can the Equivalent Sphere Model Approximate Organ Doses in Space?

    NASA Technical Reports Server (NTRS)

    Lin, Zi-Wei

    2007-01-01

    For space radiation protection it is often useful to calculate dose or dose,equivalent in blood forming organs (BFO). It has been customary to use a 5cm equivalent sphere to. simulate the BFO dose. However, many previous studies have concluded that a 5cm sphere gives very different dose values from the exact BFO values. One study [1] . concludes that a 9 cm sphere is a reasonable approximation for BFO'doses in solar particle event environments. In this study we use a deterministic radiation transport [2] to investigate the reason behind these observations and to extend earlier studies. We take different space radiation environments, including seven galactic cosmic ray environments and six large solar particle events, and calculate the dose and dose equivalent in the skin, eyes and BFO using their thickness distribution functions from the CAM (Computerized Anatomical Man) model [3] The organ doses have been evaluated with a water or aluminum shielding of an areal density from 0 to 20 g/sq cm. We then compare with results from the equivalent sphere model and determine in which cases and at what radius parameters the equivalent sphere model is a reasonable approximation. Furthermore, we address why the equivalent sphere model is not a good approximation in some cases. For solar particle events, we find that the radius parameters for the organ dose equivalent increase significantly with the shielding thickness, and the model works marginally for BFO but is unacceptable for the eye or the skin. For galactic cosmic rays environments, the equivalent sphere model with an organ-specific constant radius parameter works well for the BFO dose equivalent, marginally well for the BFO dose and the dose equivalent of the eye or the skin, but is unacceptable for the dose of the eye or the skin. The ranges of the radius parameters are also being investigated, and the BFO radius parameters are found to be significantly, larger than 5 cm in all cases, consistent with the conclusion of

  11. RESEARCH TOWARD THE DEVELOPMENT OF A BIOLOGICALLY BASED DOSE RESPONSE ASSESSMENT FOR INORGANIC ARSENIC CARCINOGENICITY: A PROGRESS REPORT

    EPA Science Inventory

    Cancer risk assessments for inorganic arsenic have been based on human epidemiological data, assuming a linear dose-response below the range of observation of tumors. Part of the reason for the continued use of the linear approach in arsenic risk assessments is the lack of an ad...

  12. Supporting Teacher Metacognition about Formative Assessment in Online Writing Environments

    ERIC Educational Resources Information Center

    Woodard, Rebecca; Magnifico, Alecia Marie; McCarthey, Sarah

    2013-01-01

    Rubrics have become popular tools for assessing student writing both in classroom and standardized testing environments. Rubric construction and efficacy, however, is a topic that has been largely sidestepped in the literature and in teacher professional development. Composing an effective rubric--particularly for instructional or formative…

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    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 themore » 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.« less

  14. A comparison of newborn stylized and tomographic models for dose assessment in paediatric radiology

    NASA Astrophysics Data System (ADS)

    Staton, R. J.; Pazik, F. D.; Nipper, J. C.; Williams, J. L.; Bolch, W. E.

    2003-04-01

    Establishment of organ doses from diagnostic and interventional examinations is a key component to quantifying the radiation risks from medical exposures and for formulating corresponding dose-reduction strategies. Radiation transport models of human anatomy provide a convenient method for simulating radiological examinations. At present, two classes of models exist: stylized mathematical models and tomographic voxel models. In the present study, organ dose comparisons are made for projection radiographs of both a stylized and a tomographic model of the newborn patient. Sixteen separate radiographs were simulated for each model at x-ray technique factors typical of newborn examinations: chest, abdomen, thorax and head views in the AP, PA, left LAT and right LAT projection orientation. For AP and PA radiographs of the torso (chest, abdomen and thorax views), the effective dose assessed for the tomographic model exceeds that for the stylized model with per cent differences ranging from 19% (AP abdominal view) to 43% AP chest view. In contrast, the effective dose for the stylized model exceeds that for the tomographic model for all eight lateral views including those of the head, with per cent differences ranging from 9% (LLAT chest view) to 51% (RLAT thorax view). While organ positioning differences do exist between the models, a major factor contributing to differences in effective dose is the models' exterior trunk shape. In the tomographic model, a more elliptical shape is seen thus providing for less tissue shielding for internal organs in the AP and PA directions, with corresponding increased tissue shielding in the lateral directions. This observation is opposite of that seen in comparisons of stylized and tomographic models of the adult.

  15. Combining Learning and Assessment in Assessment-Based Gaming Environments: A Case Study from a New York City School

    ERIC Educational Resources Information Center

    Zapata-Rivera, Diego; VanWinkle, Waverely; Doyle, Bryan; Buteux, Alyssa; Bauer, Malcolm

    2009-01-01

    Purpose: The purpose of this paper is to propose and demonstrate an evidence-based scenario design framework for assessment-based computer games. Design/methodology/approach: The evidence-based scenario design framework is presented and demonstrated by using BELLA, a new assessment-based gaming environment aimed at supporting student learning of…

  16. Competency assessment tools: An exploration of the pedagogical issues facing competency assessment for nurses in the clinical environment.

    PubMed

    Franklin, Natasha; Melville, Paula

    2015-01-01

    Competency assessment is a paradigm that is common in the healthcare environment and this being particularly true within the nursing profession. Demonstration of competence is necessary to meet the requirements of healthcare organisations and is a mandated requirement of nurses by the Nursing and Midwifery Board of Australia. Within the nursing education sector, one approach to determine competence, is through the use of competency assessment tools. Despite widespread use of competency assessment tools there remains ongoing concerns relating to the efficacy of competency assessment tools as a mean to demonstrate 'competency' amongst enrolled and registered nurses in the clinical environment. The authors of this paper ascertain that competency assessment tools run a serious risk of being nothing more than a 'quick-fix' means of assessment to demonstrate 'nursing competence' required for key performance indicators and clinical governance and that will provide evidence for accreditation standards. Based on this premise, the authors, provide an alternative approach to the use of competency assessment tools that moves away from a 'tick-box' approach to a 'patient-centred' competency model. This approach increases the reliability and validity of competency assessments, allows for the recognition of the knowledge, skills and experience of individual nurses, offers a more satisfying and rewarding approach to demonstrating 'competency' for nurses and finally, demonstrates 'real-life' competency.

  17. Primary DNA damage assessed with the comet assay and comparison to the absorbed dose of diagnostic X-rays in children.

    PubMed

    Milkovic, Durdica; Garaj-Vrhovac, Vera; Ranogajec-Komor, Mária; Miljanic, Saveta; Gajski, Goran; Knezevic, Zeljka; Beck, Natko

    2009-01-01

    The aim of this work is to assess DNA damage in peripheral blood lymphocytes of children prior to and following airway X-ray examinations of the chest using the alkaline comet assay and to compare data with the measured absorbed dose. Twenty children with pulmonary diseases, between the ages of 5 and 14 years, are assessed. Absorbed dose measurements are conducted for posterior-anterior projection on the forehead, thyroid gland, gonads, chest, and back. Doses are measured using thermoluminescent and radiophotoluminescent dosimetry systems. Differences between tail lengths, tail intensity, and tail moments as well as for the long-tailed nuclei before and after exposures are statistically significant and are dependent on the individual. The results demonstrate the usefulness of the comet assay as a measure of X-ray damage to lymphocytes in a clinical setting. Doses measured with both dosimeters show satisfactory agreement (0.01 mSv) and are suitable for dosimetric measurements in X-ray diagnostics.

  18. The State of the Environment In OECD Countries: A First Assessment.

    ERIC Educational Resources Information Center

    OECD Observer, 1979

    1979-01-01

    An assessment of the state of the environment in selected nations is presented. Criteria such as water, land, noise, chemicals, and wildlife were considered in arriving at conclusions concerning world trends in environmental quality. (RE)

  19. RADON AND PROGENY SOURCED DOSE ASSESSMENT OF SPA EMPLOYEES IN BALNEOLOGICAL SITES.

    PubMed

    Uzun, Sefa Kemal; Demiröz, Işık

    2016-09-01

    This study was conducted in the scope of IAEA project with the name 'Establishing a Systematic Radioactivity Survey and Total Effective Dose Assessment in Natural Balneological Sites' (TUR/9/018), at the Health Physics department of Sarayköy Nuclear Research and Training Center (SANAEM). The aim of this study is estimation of radon and progeny sourced effective dose for the people who are working at the spa facilities by measuring radon activity concentration (RAC) at the ambient air of indoor spa pools and dressing rooms. As it is known, the source of the radon gas is the radium content of the earth crust. Therefore, thermal waters coming from ground may contain dissolved radon and the radon can diffuse water to air. So the ambient air of spa pools can contain serious RAC that depends on a lot of parameters. In this regard, RAC measurements were executed at the 70 spa facilities in Turkey. The measurements were done with both active and passive methods at ambient air of spa pools and dressing rooms. Thus, active measurements were carried out by using the Alphaguard(®) with diffusion mode during half an hour, and passive measurements were carried out by using the humidity resistive CR-39 radon detectors during 2 months. Results show that RAC values at ambient air of spa pools varies between 13 Bq m(-3) and 10 kBq m(-3) Because long-term measurements are more reliable, if it is available, for dose calculations passive radon measurements (with CR-39 detectors) at ambient air of spa pools and dressing rooms were used, otherwise active measurement results were used. With the measurement by the conversion coefficients of ICRP 65 and occupational data of the employees has got from questionary forms, effective dose values were calculated. According to the calculations, spa employees are exposed to annual average dose between 0.05 and 29 mSv because of radon and progeny. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions

  20. Mobile-Dose: A Dose-Meter Designed for Use in Automatic Machineries for Dose Manipulation in Nuclear Medicine

    NASA Astrophysics Data System (ADS)

    de Asmundis, Riccardo; Boiano, Alfonso; Ramaglia, Antonio

    2008-06-01

    Mobile-Dose has been designed for a very innovative use: the integration in a robotic machinery for automatic preparation of radioactive doses, to be injected to patients in Nuclear Medicine Departments, with real time measurement of the activity under preparation. Mobile-Dose gives a constant measurement of the dose during the filling of vials or syringes, triggering the end of the filling process based on a predefined dose limit. Several applications of Mobile-Dose have been delivered worldwide, from Italian hospitals and clinics to European and Japanese ones. The design of such an instrument and its integration in robotic machineries, was required by an Italian company specialised in radiation protection tools for nuclear applications, in the period 2001-2003. At the time of its design, apparently no commercial instruments with a suitable interfacing capability to the external world existed: we designed it in order to satisfy all the strict requirements coming from the medical aspects (precision within 10%, repeatability, stability, time response) and from the industrial conceiving principles that are mandatory to ensure a good reliability in such a complicated environment. The instrument is suitable to be used in standalone mode too, thanks to its portability and compactness and to the intelligent operator panel programmed for this purpose.

  1. Assessment of the actual light dose in photodynamic therapy.

    PubMed

    Schaberle, Fabio A

    2018-06-09

    Photodynamic therapy (PDT) initiates with the absorption of light, which depends on the spectral overlap between the light source emission and the photosensitizer absorption, resulting in the number of photons absorbed, the key parameter starting PDT processes. Most papers report light doses regardless if the light is only partially absorbed or shifted relatively to the absorption peak, misleading the actual light dose value and not allowing quantitative comparisons between photosensitizers and light sources. In this manuscript a method is presented to calculate the actual light dose delivered by any light source for a given photosensitizer. This method allows comparing light doses delivered for any combination of light source (broad or narrow band or daylight) and photosensitizer. Copyright © 2018. Published by Elsevier B.V.

  2. A Signal-to-Noise Crossover Dose as the Point of Departure for Health Risk Assessment

    PubMed Central

    Portier, Christopher J.; Krewski, Daniel

    2011-01-01

    Background: The U.S. National Toxicology Program (NTP) cancer bioassay database provides an opportunity to compare both existing and new approaches to determining points of departure (PoDs) for establishing reference doses (RfDs). Objectives: The aims of this study were a) to investigate the risk associated with the traditional PoD used in human health risk assessment [the no observed adverse effect level (NOAEL)]; b) to present a new approach based on the signal-to-noise crossover dose (SNCD); and c) to compare the SNCD and SNCD-based RfD with PoDs and RfDs based on the NOAEL and benchmark dose (BMD) approaches. Methods: The complete NTP database was used as the basis for these analyses, which were performed using the Hill model. We determined NOAELs and estimated corresponding extra risks. Lower 95% confidence bounds on the BMD (BMDLs) corresponding to extra risks of 1%, 5%, and 10% (BMDL01, BMDL05, and BMDL10, respectively) were also estimated. We introduce the SNCD as a new PoD, defined as the dose where the additional risk is equal to the “background noise” (the difference between the upper and lower bounds of the two-sided 90% confidence interval on absolute risk) or a specified fraction thereof. Results: The median risk at the NOAEL was approximately 10%, and the default uncertainty factor (UF = 100) was considered most applicable to the BMDL10. Therefore, we chose a target risk of 1/1,000 (0.1/100) to derive an SNCD-based RfD by linear extrapolation. At the median, this approach provided the same RfD as the BMDL10 divided by the default UF. Conclusions: Under a standard BMD approach, the BMDL10 is considered to be the most appropriate PoD. The SNCD approach, which is based on the lowest dose at which the signal can be reliably detected, warrants further development as a PoD for human health risk assessment. PMID:21813365

  3. 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.

  4. 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.

  5. Towards new methods for the determination of dose limiting toxicities and the assessment of the recommended dose for further studies of molecularly targeted agents--dose-Limiting Toxicity and Toxicity Assessment Recommendation Group for Early Trials of Targeted therapies, an European Organisation for Research and Treatment of Cancer-led study.

    PubMed

    Postel-Vinay, Sophie; Collette, Laurence; Paoletti, Xavier; Rizzo, Elisa; Massard, Christophe; Olmos, David; Fowst, Camilla; Levy, Bernard; Mancini, Pierre; Lacombe, Denis; Ivy, Percy; Seymour, Lesley; Le Tourneau, Christophe; Siu, Lillian L; Kaye, Stan B; Verweij, Jaap; Soria, Jean-Charles

    2014-08-01

    Traditional dose-limiting toxicity (DLT) definition, which uses grade (G) 3-4 toxicity data from cycle 1 (C1) only, may not be appropriate for molecularly targeted agents (MTAs) of prolonged administration, for which late or lower grade toxicities also deserve attention. In collaboration with pharmaceutical companies and academia, an European Organisation for Research and Treatment of Cancer (EORTC)-led initiative, Dose-Limiting Toxicity and Toxicity Assessment Recommendation Group for Early Trials of Targeted therapies (DLT-TARGETT), collected data from completed phase 1 trials evaluating MTAs as monotherapy. All toxicities at least possibly related to the study drugs that occurred during C1-6, their type, grade (CTCAEv3.0), and duration as well as patients' relative dose-intensity (RDI), were recorded. The 54 eligible trials enrolled 2084 evaluable adult patients with solid tumours between 1999 and 2013, and evaluated small molecules (40), antibodies (seven), recombinant peptides (five) and antisense oligodeoxynucleotides (two). A maximum tolerated dose was set in 43 trials. Fifteen percent of the patients received <75% of the intended RDI in C1, but only 9.1% of them presented protocol-defined DLTs. After C1, 16-19% of patients received <75% of the intended RDI. A similar proportion of G ⩾ 3 toxicities was recorded in C1 and after C1 (936 and 1087 toxicities, respectively), with the first G⩾3 toxicity occurring after C1 in 18.6% of patients. Although protocol-defined DLT period is traditionally limited to C1, almost 20% of patients present significant reductions in RDI at any time in phase 1 trials of MTAs. Recommended phase 2 dose assessment should incorporate all available information from any cycle (notably lower grade toxicities leading to such RDI decrease), and be based on achieving >75% RDI. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Assessment of environmental consequences of the normal operations of the ESS facility

    NASA Astrophysics Data System (ADS)

    Ene, D.; Avila, R.; Hjerpe, T.; Bugay, D.; Stenberg, K.

    2018-06-01

    As other accelerator based facilities, the European Spallation Source ESS facility will interact with the environment. The Swedish legislation requires a demonstration that the sum of the doses resulting from the exposure of any member of the public to ionizing radiation dose does not exceed the specified limit of 50 μSv/year. A radiological assessment has been produced to provide that demonstration. This evaluation was based upon the actual status of the ESS design. A graded approach was adopted through over the assessment allowing estimating dose for all radionuclides and exposure pathways, but the degree of detail in the assessment depend upon their relative radiological importance. The total dose was obtained making the sum of the contribution of all-important radionuclides treated realistically with that of all screened out radionuclides, derived by means a conservative method.

  7. Unit-Dose Bags For Formulating Intravenous Solutions

    NASA Technical Reports Server (NTRS)

    Finley, Mike; Kipp, Jim; Scharf, Mike; Packard, Jeff; Owens, Jim

    1993-01-01

    Smaller unit-dose flowthrough bags devised for use with large-volume parenteral (LVP) bags in preparing sterile intravenous solutions. Premeasured amount of solute stored in such unit-dose bag flushed by predetermined amount of water into LVP bag. Relatively small number of LVP bags used in conjunction with smaller unit-dose bags to formulate large number of LVP intravenous solutions in nonsterile environment.

  8. Assessment of the dose reduction potential of a model-based iterative reconstruction algorithm using a task-based performance metrology

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Samei, Ehsan, E-mail: samei@duke.edu; Richard, Samuel

    2015-01-15

    Purpose: Different computed tomography (CT) reconstruction techniques offer different image quality attributes of resolution and noise, challenging the ability to compare their dose reduction potential against each other. The purpose of this study was to evaluate and compare the task-based imaging performance of CT systems to enable the assessment of the dose performance of a model-based iterative reconstruction (MBIR) to that of an adaptive statistical iterative reconstruction (ASIR) and a filtered back projection (FBP) technique. Methods: The ACR CT phantom (model 464) was imaged across a wide range of mA setting on a 64-slice CT scanner (GE Discovery CT750 HD,more » Waukesha, WI). Based on previous work, the resolution was evaluated in terms of a task-based modulation transfer function (MTF) using a circular-edge technique and images from the contrast inserts located in the ACR phantom. Noise performance was assessed in terms of the noise-power spectrum (NPS) measured from the uniform section of the phantom. The task-based MTF and NPS were combined with a task function to yield a task-based estimate of imaging performance, the detectability index (d′). The detectability index was computed as a function of dose for two imaging tasks corresponding to the detection of a relatively small and a relatively large feature (1.5 and 25 mm, respectively). The performance of MBIR in terms of the d′ was compared with that of ASIR and FBP to assess its dose reduction potential. Results: Results indicated that MBIR exhibits a variability spatial resolution with respect to object contrast and noise while significantly reducing image noise. The NPS measurements for MBIR indicated a noise texture with a low-pass quality compared to the typical midpass noise found in FBP-based CT images. At comparable dose, the d′ for MBIR was higher than those of FBP and ASIR by at least 61% and 19% for the small feature and the large feature tasks, respectively. Compared to FBP and ASIR

  9. Determining the Optimal Dose of Adenosine for Unmasking Dormant Pulmonary Vein Conduction Following Atrial Fibrillation Ablation: Electrophysiological and Hemodynamic Assessment. DORMANT-AF Study.

    PubMed

    Prabhu, Sandeep; Mackin, Vincent; McLellan, Alex J A; Phan, Tuong; McGlade, Desmond; Ling, Liang-Han; Peck, Kah Y; Voskoboinik, Alexandr; Pathik, Bupesh; Nalliah, Chrishan J; Wong, Geoff R; Azzopardi, Sonia M; Lee, Geoffrey; Mariani, Justin; Taylor, Andrew J; Kalman, Jonathan M; Kistler, Peter M

    2017-01-01

    ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT. The significance of adenosine induced dormant pulmonary vein (PV) conduction in atrial fibrillation (AF) ablation remains controversial. The optimal dose of adenosine to determine dormant PV conduction is yet to be systematically explored. ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT. Consecutive patients undergoing index AF ablation received 3 adenosine doses (12, 18, and 24 mg) in a randomized blinded order, immediately after pulmonary vein isolation (PVI). Electrophysiological (PR prolongation, AV block (AVB) and PV reconnection) and hemodynamic (BP) parameters were measured. A total, 339 doses (113/dose) assessed 191 PVs in 50 patients (66% male, 72% PAF, 52% hypertensive). Dormant PV conduction occurred in 28% of patients (16.5% [32] of PVs). All cases were associated with AVB (AVB: PV reconnection vs. no PV reconnection 100% vs. 83%, P = 0.007). AVB occurred more frequently at 24 mg versus 12 mg (92% vs. 82%, P = 0.019) but not versus 18 mg (91%, P = 0.62). AVB duration progressed between 12 mg (12.0 ± 8.9 seconds), 18 mg (16.1 ± 9.1 seconds, P = 0.001), and 24 mg (19.0 ± 9.3 seconds, P < 0.001) doses. MBP fell further at 24 mg (ΔMBP: 27 ± 12 mmHg) and 18 mg (26 ± 13 mmHg) doses compared to 12 mg (22 ± 10 mmHg vs., P < 0.001). A significant reduction in AVB in patients >110 kg (65% vs. 91% in 70-110 kg group, P < 0.001) in response to adenosine was seen. ELECTROPHYSIOLOGICAL AND HEMODYNAMIC ASSESSMENT. An adenosine dose producing AVB is required to unmask dormant PV conduction. AVB is significantly reduced in patients >110 kg. Weight and dosing variability may in part explain the conflicting results of studies evaluating the clinical utility of adenosine in PVI. © 2016 Wiley Periodicals, Inc.

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

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Longgao, E-mail: chenlonggao@163.com; Yang, Xiaoyan; School of Environment and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116

    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 illustratedmore » 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

  11. Global Channels of Evidence for Learning and Assessment in Complex Game Environments

    ERIC Educational Resources Information Center

    Nelson, Brian C.; Erlandson, Benjamin; Denham, Andre

    2011-01-01

    In this paper, we take a designer's look at how the activities and data of learning and assessment can be structured in immersive virtual game environments called Massively Multi-Player Online Games (MMOG). In doing so, we examine the channels of evidence through which learning and assessment activities are derived in MMOGs, offering examples of…

  12. Assessment of peak skin dose in interventional cardiology: A comparison between Gafchromic film and dosimetric software em.dose.

    PubMed

    Greffier, J; Van Ngoc Ty, C; Bonniaud, G; Moliner, G; Ledermann, B; Schmutz, L; Cornillet, L; Cayla, G; Beregi, J P; Pereira, F

    2017-06-01

    To compare the use of a dose mapping software to Gafchromic film measurement for a simplified peak skin dose (PSD) estimation in interventional cardiology procedure. The study was conducted on a total of 40 cardiac procedures (20 complex coronary angioplasty of chronic total occlusion (CTO) and 20 coronary angiography and coronary angioplasty (CA-PTCA)) conducted between January 2014 to December 2015. PSD measurement (PSD Film ) was obtained by placing XR-RV3 Gafchromic under the patient's back for each procedure. PSD (PSD em.dose ) was computed with the software em.dose©. The calculation was performed on the dose metrics collected from the private dose report of each procedure. Two calculation methods (method A: fluoroscopic kerma equally spread on cine acquisition and B: fluoroscopic kerma is added to one air Kerma cine acquisition that contributes to the PSD) were used to calculate the fluoroscopic dose contribution as fluoroscopic data were not recorded in our interventional room. Statistical analyses were carried out to compare PSD Film and PSD em.dose . The PSD Film median (1st quartile; 3rd quartile) was 0.251(0.190;0.336)Gy for CA-PTCA and 1.453(0.767;2.011)Gy for CTO. For method-A, the PSD em.dose was 0.248(0.182;0.369)Gy for CA-PTCA and 1.601(0.892;2.178)Gy for CTO, and 0.267(0.223;0.446)Gy and 1.75 (0.912;2.584)Gy for method-B, respectively. For the two methods, the correlation between PSD Film and PSD em.dose was strong. For all cardiology procedures investigated, the mean deviation between PSD Film and PSD em.dose was 3.4±21.1% for method-A and 17.3%±23.9% for method-B. The dose mapping software is convenient to calculate peak skin dose in interventional cardiology. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  13. Assessment of serum magnesium levels and its outcome in neonates of eclamptic mothers treated with low-dose magnesium sulfate regimen

    PubMed Central

    Das, Monalisa; Chaudhuri, Patralekha Ray; Mondal, Badal C.; Mitra, Sukumar; Bandyopadhyay, Debasmita; Pramanik, Sushobhan

    2015-01-01

    Objectives: Magnesium historically has been used for treatment and/or prevention of eclampsia. Considering the low body mass index of Indian women, a low-dose magnesium sulfate regime has been introduced by some authors. Increased blood levels of magnesium in neonates is associated with increased still birth, early neonatal death, birth asphyxia, bradycardia, hypotonia, gastrointestinal hypomotility. The objective of this study was to assess safety of low-dose magnesium sulfate regimen in neonates of eclamptic mothers treated with this regimen. Materials and Methods: This was a cross-sectional observational study of 100 eclampsia patients and their neonates. Loading dose and maintenance doses of magnesium sulfate were administered to patients by combination of intravenous and intramuscular routes. Maternal serum and cord blood magnesium levels were estimated. Neonatal outcome was assessed. Results: Bradycardia was observed in 18 (19.15%) of the neonates, 16 (17.02%) of the neonates were diagnosed with hypotonia. Pearson Correlation Coefficient showed Apgar scores decreased with increase in cord blood magnesium levels. Unpaired t-test showed lower Apgar scores with increasing dose of magnesium sulfate. The Chi-square/Fisher's exact test showed significant increase in hypotonia, birth asphyxia, intubation in delivery room, Neonatal Intensive Care Unit (NICU) care requirement, with increasing dose of magnesium sulfate. (P ≤ 0.05). Conclusion: Several neonatal complications are significantly related to increasing serum magnesium levels. Overall, the low-dose magnesium sulfate regimen was safe in the management of eclamptic mothers, without toxicity to their neonates. PMID:26600638

  14. Activity concentrations of (137)Caesium and (210)Polonium in seafood from fishing regions of New Zealand and the dose assessment for seafood consumers.

    PubMed

    Pearson, Andrew J; Gaw, Sally; Hermanspahn, Nikolaus; Glover, Chris N

    2016-01-01

    A study was undertaken to determine activity concentrations for (134)Caesium, (137)Caesium and (210)Polonium in New Zealand seafood, and establish if activity concentrations varied with respect to species/ecological niche and coastal region. Thirty seafood samples were obtained from six fishing regions of New Zealand along with a further six samples of two commercially important species (hoki and arrow squid) with well-defined fisheries. (134)Caesium was not detected in any sample. (137)Caesium was detected in 47% of samples, predominantly in pelagic fish species, with most activities at a trace level. Detections of (137)Caesium were evenly distributed across all regions. Activity concentrations were consistent with those expected from the oceanic inventory representing residual fallout from global nuclear testing. (210)Polonium was detected above the minimum detectable concentration in 33 (92%) of the analysed samples. Molluscs displayed significantly elevated activity concentrations relative to all other species groups. No significant regional variation in activity concentrations were determined. Two dose assessment models for high seafood consumers were undertaken. Dose contribution from (137)Caesium was minimal and far below the dose exemption limit of 1 mSv/year. Exposure to (210)Polonium was significant in high seafood consumers at 0.44-0.77 mSv/year (5th-95th percentile). (137)Caesium is concluded to be a valuable sentinel radionuclide for monitoring anthropogenic releases, such as global fallout and reactor releases, in the marine environment. (210)Polonium is of importance as a natural radionuclide sentinel due to its high contribution to dietary committed dose in seafood consumers. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Participation-based environment accessibility assessment tool (P-BEAAT) in the Zambian context.

    PubMed

    Banda-Chalwe, Martha; Nitz, Jennifer C; de Jonge, Desleigh

    2012-01-01

    The purpose of this study was to describe the preliminary development and validation of a potential measure for assessing the accessibility of the built environment in Zambia. It was designed to identify environmental features that present barriers to participation for people with mobility limitations (PWML) using mobility devices such as wheelchairs or crutches. The Participation-Based Environment Accessibility Assessment Tool (P-BEAAT) was developed through focus group discussions and personal interviews with 88 PWML from five provinces of Zambia regarding the accessibility of their built environment. The content validity of the P-BEAAT checklist was accomplished through three phases of development with data gathered from 11 focus groups and nine personal interviews. Participants described accessibility barriers which affect their participation in daily life. This information generated the P-BEAAT with 66 items describing eight environmental features with potential for identifying environmental barriers. The P-BEAAT has shown good homogeneity with Cronbach's α score of 0.91. The P-BEAAT was constructed grounded in the reality of people's experiences in Zambia for use in assessing environmental features important in the participation of daily life of PWML pertinent to developing countries. Further clinimetric testing of the properties of the P-BEAAT to establish reliability should be conducted next.

  16. Student self-assessment in an interactive learning environment: Technological tools for scaffolding and understanding self-assessment practices

    NASA Astrophysics Data System (ADS)

    Eslinger, Eric Martin

    Metacognitive skills are a crucial component of a successful learning career. We define metacognition as the ability to plan, monitor progress toward a goal, reflect on the quality of work and process, and revise the work or plan accordingly. By explicitly addressing certain metacognitive practices in classrooms, researchers have observed improved learning outcomes in both science and mathematical problem solving. Although these efforts were successful, they were also limited in the range of skills that could be addressed at one time and the methods used to address them due to the static nature inherent in traditional pencil-and-paper format. We wished to address these skills in a more dynamic, continuous representation such as that afforded by a computerized learning environment. This paper outlines such an environment and describes pedagogical activities afforded by the system. The ThinkerTools group developed and tested a software scaffold for inquiry projects in a middle-school classroom. By analyzing student use of the software tool, three forms of self-assessment activity were noted: integrated, task and project self-assessment. Each assessment form was related to the degree of interleaving between assessment and work the students engaged in as they developed their inquiry products. I argue that the integrated forms of assessment are more beneficial to student learning, and show that there is a significant relationship between active self-assessment forms and measures of student achievement and product quality. Through the use of case studies including video analysis, I address specific student self-assessment activity that utilized the software as well as self-assessment that took place outside of the software. A model of student self-assessment activity was created, highlighting aspects of activity that afford more productive self-assessment episodes.

  17. Implications of free breathing motion assessed by 4D-computed tomography on the delivered dose in radiotherapy for esophageal cancer.

    PubMed

    Duma, Marciana Nona; Berndt, Johannes; Rondak, Ina-Christine; Devecka, Michal; Wilkens, Jan J; Geinitz, Hans; Combs, Stephanie Elisabeth; Oechsner, Markus

    2015-01-01

    The aim of this study was to assess the effect of breathing motion on the delivered dose in esophageal cancer 3-dimensional (3D)-conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT). We assessed 16 patients with esophageal cancer. All patients underwent 4D-computed tomography (4D-CT) for treatment planning. For each of the analyzed patients, 1 3D-CRT, 1 IMRT, and 1 VMAT (RapidArc-RA) plan were calculated. Each of the 3 initial plans was recalculated on the 4D-CT (for the maximum free inspiration and maximum free expiration) to assess the effect of breathing motion. We assessed the minimum dose (Dmin) and mean dose (Dmean) to the esophagus within the planning target volume, the volume changes of the lungs, the Dmean and the total lung volume receiving at least 40Gy (V40), and the V30, V20, V10, and V5. For the heart we assessed the Dmean and the V25. Over all techniques and all patients the change in Dmean as compared with the planned Dmean (planning CT [PCT]) to the esophagus was 0.48% in maximum free inspiration (CT_insp) and 0.55% in maximum free expiration (CT_exp). The Dmin CT_insp change was 0.86% and CT_exp change was 0.89%. The Dmean change of the lungs (heart) was in CT_insp 1.95% (2.89%) and 3.88% (2.38%) in CT_exp. In all, 4 patients had a clinically relevant change of the dose (≥ 5% Dmean to the heart and the lungs) between inspiration and expiration. These patients had a very cranially or caudally situated tumor. There are no relevant differences in the delivered dose to the regions of interest among the 3 techniques. Breathing motion management could be considered to achieve a better sparing of the lungs or heart in patients with cranially or caudally situated tumors. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

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

    PubMed

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

    2017-02-01

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

  19. SU-E-J-93: Parametrisation of Dose to the Mucosa of the Anterior Rectal Wall in Transrectal Ultrasound Guided High-Dose-Rate Brachytherapy of the Prostate

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aitkenhead, A; Hamlett, L; Wood, D

    2014-06-01

    Purpose: In high-dose-rate (HDR) brachytherapy of the prostate, radiation is delivered from a number of radioactive sources which are inserted via catheter into the target volume. The rectal mucosa also receives dose during the treatment, which may lead to late toxicity effects. To allow possible links between rectal dose and toxicity to be investigated, suitable methods of parametrising the rectal dose are needed. Methods: During treatment of a series of 95 patients, anatomy and catheter locations were monitored by transrectal ultrasound, and target volume positions were contoured on the ultrasound scan by the therapist. The anterior rectal mucosal wall wasmore » identified by contouring the transrectal ultrasound balloon within the ultrasound scan. Source positions and dwell times, along with the dose delivered to the patient were computed using the Oncentra Prostate treatment planning system (TPS). Data for the series of patients were exported from the TPS in Dicom format, and a series of parametrisation methods were developed in a Matlab environment to assess the rectal dose. Results: Contours of the anterior rectal mucosa were voxelised within Matlab to allow the dose to the rectal mucosa to be analysed directly from the 3D dose grid. Dose parametrisations based on dose-surface (DSH) and dose-line (DLH) histograms were obtained. Both lateral and longitudinal extents of the mucosal dose were parametrised using dose-line histograms in the relevant directions. Conclusion: We have developed a series of dose parametrisations for quantifying the dose to the rectal mucosa during HDR prostate brachytherapy which are suitable for future studies investigating potential associations between mucosal dose and late toxicity effects. The geometry of the transrectal probe standardises the rectal anatomy, making this treatment technique particularly suited to studies of this nature.« less

  20. Assessing Educational Environments.

    ERIC Educational Resources Information Center

    New Directions for Testing and Measurement, 1980

    1980-01-01

    Educational environment data derived from classroom settings strongly suggest the positive contribution that climate variables can make in accounting for learning performance. Such measures are not only related to productivity but may constitute criterion variables in and of themselves. (Author)

  1. 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.

  2. Assessment of nutrition and physical activity environments in family child care homes: modification and psychometric testing of the Environment and Policy Assessment and Observation.

    PubMed

    Vaughn, Amber E; Mazzucca, Stephanie; Burney, Regan; Østbye, Truls; Benjamin Neelon, Sara E; Tovar, Alison; Ward, Dianne S

    2017-08-29

    Early care and education (ECE) settings play an important role in shaping the nutrition and physical activity habits of young children. Increasing research attention is being directed toward family child care homes (FCCHs) specifically. However, existing measures of child care nutrition and physical activity environments are limited in that they have been created for use with center-based programs and require modification for studies involving FCCHs. This paper describes the modification of the Environment and Policy Assessment and Observation (EPAO) for use in FCCHs. The EPAO underwent a through modification process that incorporated an updated format for the data collection instrument, assessment of emerging best practices, tailoring to the FCCH environment, and creation of a new scoring rubric. The new instrument was implemented as part of a larger randomized control trial. To assess inter-rater reliability, observations on 61 different days were performed independently by two data collectors. To assess construct validity, associations between EPAO scores and measures of children's dietary intake (Healthy Eating Index (HEI) score) and physical activity (accelerometer-measured minutes per hour of moderate to vigorous physical activity, MVPA) were examined. The modified EPAO assesses 38 nutrition and 27 physical activity best practices, which can be summarized into 7 nutrition-related and 10 physical activity-related environmental sub- scores as well as overall nutrition and overall physical activity scores. There was generally good agreement between data collectors (ICC > 0.60). Reliability was slightly lower for feeding practices and physical activity education and professional development (ICC = 0.56 and 0.22, respectively). Child HEI was significantly correlated with the overall nutrition score (r = 0.23), foods provided (r = 0.28), beverages provided (r = 0.15), nutrition education and professional development (r = 0.21), and nutrition policy (r

  3. Benchmark Dose Analysis from Multiple Datasets: The Cumulative Risk Assessment for the N-Methyl Carbamate Pesticides

    EPA Science Inventory

    The US EPA’s N-Methyl Carbamate (NMC) Cumulative Risk assessment was based on the effect on acetylcholine esterase (AChE) activity of exposure to 10 NMC pesticides through dietary, drinking water, and residential exposures, assuming the effects of joint exposure to NMCs is dose-...

  4. Evaluation of low-dose dual energy computed tomography for in vivo assessment of renal/ureteric calculus composition.

    PubMed

    Mahalingam, Harshavardhan; Lal, Anupam; Mandal, Arup K; Singh, Shrawan Kumar; Bhattacharyya, Shalmoli; Khandelwal, Niranjan

    2015-08-01

    This study aimed to assess the accuracy of low-dose dual-energy computed tomography (DECT) in predicting the composition of urinary calculi. A total of 52 patients with urinary calculi were scanned with a 128-slice dual-source DECT scanner by use of a low-dose protocol. Dual-energy (DE) ratio, weighted average Hounsfield unit (HU) of calculi, radiation dose, and image noise levels were recorded. Two radiologists independently rated study quality. Stone composition was assessed after extraction by Fourier transform infrared spectroscopy (FTIRS). Analysis of variance was used to determine if the differences in HU values and DE ratios between the various calculus groups were significant. Threshold cutoff values to classify the calculi into separate groups were identified by receiver operating characteristic curve analysis. A total of 137 calculi were detected. FTIRS analysis differentiated the calculi into five groups: uric acid (n=17), struvite (n=3), calcium oxalate monohydrate and dihydrate (COM-COD, n=84), calcium oxalate monohydrate (COM, n=28), and carbonate apatite (n=5). The HU value could differentiate only uric acid calculi from calcified calculi (p<0.001). The DE ratio could confidently differentiate uric acid, struvite, calcium oxalate, and carbonate apatite calculi (p<0.001) with cutoff values of 1.12, 1.34, and 1.66, respectively, giving >80% sensitivity and specificity to differentiate them. The DE ratio could not differentiate COM from COM-COD calculi. No study was rated poor in quality by either of the observers. The mean radiation dose was 1.8 mSv. Low-dose DECT accurately predicts urinary calculus composition in vivo while simultaneously reducing radiation exposure without compromising study quality.

  5. Evaluation of low-dose dual energy computed tomography for in vivo assessment of renal/ureteric calculus composition

    PubMed Central

    Mahalingam, Harshavardhan; Mandal, Arup K; Singh, Shrawan Kumar; Bhattacharyya, Shalmoli; Khandelwal, Niranjan

    2015-01-01

    Purpose This study aimed to assess the accuracy of low-dose dual-energy computed tomography (DECT) in predicting the composition of urinary calculi. Materials and Methods A total of 52 patients with urinary calculi were scanned with a 128-slice dual-source DECT scanner by use of a low-dose protocol. Dual-energy (DE) ratio, weighted average Hounsfield unit (HU) of calculi, radiation dose, and image noise levels were recorded. Two radiologists independently rated study quality. Stone composition was assessed after extraction by Fourier transform infrared spectroscopy (FTIRS). Analysis of variance was used to determine if the differences in HU values and DE ratios between the various calculus groups were significant. Threshold cutoff values to classify the calculi into separate groups were identified by receiver operating characteristic curve analysis. Results A total of 137 calculi were detected. FTIRS analysis differentiated the calculi into five groups: uric acid (n=17), struvite (n=3), calcium oxalate monohydrate and dihydrate (COM-COD, n=84), calcium oxalate monohydrate (COM, n=28), and carbonate apatite (n=5). The HU value could differentiate only uric acid calculi from calcified calculi (p<0.001). The DE ratio could confidently differentiate uric acid, struvite, calcium oxalate, and carbonate apatite calculi (p<0.001) with cutoff values of 1.12, 1.34, and 1.66, respectively, giving >80% sensitivity and specificity to differentiate them. The DE ratio could not differentiate COM from COM-COD calculi. No study was rated poor in quality by either of the observers. The mean radiation dose was 1.8 mSv. Conclusions Low-dose DECT accurately predicts urinary calculus composition in vivo while simultaneously reducing radiation exposure without compromising study quality. PMID:26279828

  6. Pesticide Dose - A Parameter with Many Implications

    USDA-ARS?s Scientific Manuscript database

    Like pharmaceuticals, pesticides can have unintended effects, even when used at the proper dose. For pesticides, the possible effects are even more diverse, because the chemicals are released immediately into the environment and the dose reaching the intended target(s) and unintended targets can var...

  7. Case control study to assess the possibility of decrease the risk of osteoradionecrosis in relation to the dose of radiation absorbed by the jaw

    PubMed Central

    Carini, Fabrizio; Bucalo, Concetta; Saggese, Vito; Monai, Dario; Porcaro, Gianluca

    2012-01-01

    Summary Aims the assessment of the limit dose for the organs at risk in external radiotherapy is a fundamental step to guarantee an optimal risk-benefit ratio. The aim of this study was to assess, through contouring the single dental cavities, the absorbed radiation dose on irradiated alveolar bones during the treatment of cervico-facial tumours, so as to test the correlation between the absorbed dose of radiation at alveolar level and the level of individual surgical risk for osteonecrosis. Materials and methods we selected 45 out of 89 patients on the basis of different exclusion criteria. Nine of these patients showed evidence of osteoradionecrosis. The patients were treated either with 3D conformational radiation therapy (3D-CRT) or with intensity-modulated radiation therapy (IMRT), there after alveolar bones were contoured using computed axial tomography (CAT scans) carried out following oncological and dental treatment. The dose-volume histograms (DVH) were obtained on the basis of such data, which included those relating to the dental cavities in addition to those inherent to the tumours and the organs at risk. Results all patients, irrespective of type of treatment, received an average of 60 to 70 grays in 30/35 sittings. The patients treated with IMRT showed higher variation in absorbed radiation dose than those treated with 3D-CRT. The alveolar encirclement allowed the assessment of the absorbed radiation dose, and consequently it also allowed to assess the individual surgical risk for osteonecrosis in patients with head and neck tumours who underwent radiography treatment. Conclusions the study of DVH allows the assessment of limit dose and the detection of the areas at greater risk for osteoradionecrosis before dental surgery. PMID:23285316

  8. PCC-FISH in skin fibroblasts for local dose assessment: biodosimetric analysis of a victim of the Georgian radiological accident.

    PubMed

    Pouget, J-P; Laurent, C; Delbos, M; Benderitter, M; Clairand, I; Trompier, F; Stéphanazzi, J; Carsin, H; Lambert, F; Voisin, P; Gourmelon, P

    2004-10-01

    We propose a new method of biodosimetry that could be applied in cases of localized irradiation. The approach is based on excess chromosome segments determination by the PCC-FISH technique in fibroblasts isolated from skin biopsy. Typically, 0 to 10 Gy ex vivo gamma-irradiated human skin biopsies were dissociated and fibroblasts were isolated and grown for several days. Cells next underwent PCC-FISH painting of whole chromosome 4, and the number of excess chromosome segments per metaphase was determined. An ex vivo reference curve correlating the number of excess chromosome segments per metaphase to the radiation dose was established and used to assess the dose delivered to the skin of one of the victims of the radiological accident that occurred at Lia in Georgia in December 2001. Specifically, the victim suffering from moist desquamation underwent skin excision in Hospital Percy (France). Measurement of excess chromosome segments per metaphase was done in fibroblasts isolated and grown from removed wounded skin and subsequent conversion to radiation doses was performed. The radiation dose map obtained was shown to be in accordance with clinical data and physical dosimetry as well as with conventional biodosimetry. These results demonstrated that PCC-FISH painting applied to skin fibroblasts may be a suitable technique for dose estimation. To assess its worth, this approach needs to be extended to future accidents involving localized radiation exposure.

  9. The use of TLD-700H dosemeters in the assessment of external doses at the former Semipalatinsk nuclear test site.

    PubMed

    Hill, P; Dederichs, H; Pillath, J; Schlecht, W; Hille, R; Artemev, O; Ptitskaya, L; Akhmetov, M

    2002-01-01

    The joint projects performed since 1995 by the Jülich Research Centre in co-operation with the Kazakh National Nuclear Centre in the area of the former nuclear test site near Semipalatinsk, in eastern Kazakhstan, have assessed the current dose rate of the population at and around the test site, as well as determining retrospectively the dose rate of persons affected by the atmospheric tests. Measurements of the population by personal dosemeters depend on reliably wearing these dosemeters over prolonged periods of time, and of a sufficient dosemeter return. In the past, such measurements have been particularly successful whenever short wearing times were possible. This requires high sensitivity of the dosemeters. The suitability of the highly sensitive TLD material of the BICRON TLD 700H type for such personal dosimetry measurements was investigated. It was tested in practical field application at the Semipalatinsk nuclear test site in September 2000. Initial results are available from individual doses received by a group of geologists and a group of herdsmen at the test site. For the first time, the individual dose was measured directly in these population groups. Detection limits below 1 microSv permit informative measurements for wearing times of less than two weeks. Most individual doses did not arise significantly out of local fluctuations of natural background. A conservative assessment from the aspect of practical health physics yielded a mean personal dose of 0.55 microSv per day for the herdsmen, whereas the geologists received a mean personal dose of 0.45 microSv per day. For an annual exposure period of typically, about three months, the radiation dose received by the persons investigated, in addition to the natural radiation exposure, is thus well below the international limit value of 1 mSv x a(-1) for the population dose.

  10. Assessment of Dose to the Nursing Infant from Radionuclides in Breast Milk

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Leggett, Richard Wayne; Eckerman, Keith F

    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.more » 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.« less

  11. Assessment of the feasibility of using transrectal ultrasound for postimplant dosimetry in low-dose-rate prostate brachytherapy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Davies, Rhian Siân, E-mail: rhian.s.davies@wales.nhs.uk; Perrett, Teresa; Powell, Jane

    A study was performed to establish whether transrectal ultrasound (TRUS)-based postimplant dosimetry (PID) is both practically feasible and comparable to computed tomography (CT)-based PID, recommended in current published guidelines. In total, 22 patients treated consecutively at a single cancer center with low-dose-rate (LDR) brachytherapy for early-stage prostate cancer had a transrectal ultrasound performed immediately after implant (d0-TRUS) and computed tomography scan 30 days after implant (d30-CT). Postimplant dosimetry planning was performed on both image sets and the results were compared. The interobserver reproducibility of the transrectal ultrasound postimplant dosimetry planning technique was also assessed. It was noticed that there wasmore » no significant difference in mean prostate D{sub 90} (136.5 Gy and 144.4 Gy, p = 0.2197), V{sub 100} (86.4% and 89.1%, p = 0.1480) and V{sub 150} (52.0% and 47.8%, p = 0.1657) for d30-CT and d0-TRUS, respectively. Rectal doses were significantly higher for d0-TRUS than d30-CT. Urethral doses were available with d0-TRUS only. We have shown that d0-TRUS PID is a useful tool for assessing the quality of an implant after low-dose-rate prostate brachytherapy and is comparable to d30-CT PID. There are clear advantages to its use in terms of resource and time efficiency both for the clinical team and the patient.« less

  12. Image quality evaluation and patient dose assessment of medical fluoroscopic X-ray systems: a national study.

    PubMed

    Economides, S; Hourdakis, C J; Kalivas, N; Kalathaki, M; Simantirakis, G; Tritakis, P; Manousaridis, G; Vogiatzi, S; Kipouros, P; Boziari, A; Kamenopoulou, V

    2008-01-01

    This study presents the results from a survey conducted by the Greek Atomic Energy Commission (GAEC), during the period 1998-2003, in 530 public and private owned fluoroscopic X-ray systems in Greece. Certain operational parameters for conventional and remote control systems were assessed, according to a quality control protocol developed by GAEC on the basis of the current literature. Public (91.5%) and private (81.5%) owned fluoroscopic units exhibit high-contrast resolution values over 1 lp mm(-1). Moreover, 88.5 and 87.1% of the fluoroscopic units installed in the public and private sector, respectively, present Maximum Patient Entrance Kerma Rate values lower than 100 mGy min(-1). Additionally, 68.3% of the units assessed were found to perform within the acceptance limits. Finally, the third quartile of the Entrance Surface Dose Rate distribution was estimated according to the Dose Reference Level definition and found equal to 35 mGy min(-1).

  13. Genotoxic effects of high dose rate X‐ray and low dose rate gamma radiation in ApcMin/+ mice

    PubMed Central

    Eide, Dag M.; Brede, Dag A.; Ellender, Michele; Lindbo Hansen, Elisabeth; Oughton, Deborah H.; Bouffler, Simon D.; Brunborg, Gunnar; Olsen, Ann Karin

    2017-01-01

    Risk estimates for radiation‐induced cancer in humans are based on epidemiological data largely drawn from the Japanese atomic bomb survivor studies, which received an acute high dose rate (HDR) ionising radiation. Limited knowledge exists about the effects of chronic low dose rate (LDR) exposure, particularly with respect to the application of the dose and dose rate effectiveness factor. As part of a study to investigate the development of colon cancer following chronic LDR vs. acute HDR radiation, this study presents the results of genotoxic effects in blood of exposed mice. CBAB6 F1 Apc+/+ (wild type) and ApcMin/+ mice were chronically exposed to estimated whole body absorbed doses of 1.7 or 3.2 Gy 60Co‐γ‐rays at a LDR (2.2 mGy h−1) or acutely exposed to 2.6 Gy HDR X‐rays (1.3 Gy min−1). Genotoxic endpoints assessed in blood included chromosomal damage (flow cytometry based micronuclei (MN) assay), mutation analyses (Pig‐a gene mutation assay), and levels of DNA lesions (Comet assay, single‐strand breaks (ssb), alkali labile sites (als), oxidized DNA bases). Ionising radiation (ca. 3 Gy) induced genotoxic effects dependent on the dose rate. Chromosomal aberrations (MN assay) increased 3‐ and 10‐fold after chronic LDR and acute HDR, respectively. Phenotypic mutation frequencies as well as DNA lesions (ssb/als) were modulated after acute HDR but not after chronic LDR. The ApcMin/+ genotype did not influence the outcome in any of the investigated endpoints. The results herein will add to the scant data available on genotoxic effects following chronic LDR of ionising radiation. Environ. Mol. Mutagen. 58:560–569, 2017. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society PMID:28856770

  14. Challenges in coupling LTER with environmental assessments: An insight from potential and reality of the Chinese Ecological Research Network in servicing environment assessments.

    PubMed

    Xia, Shaoxia; Liu, Yu; Yu, Xiubo; Fu, Bojie

    2018-08-15

    Environmental assessments estimate, evaluate and predict the consequences of natural processes and human activities on the environment. Long-term ecosystem observation and research networks (LTERs) are potentially valuable infrastructure to support environmental assessments. However, very few environmental assessments have successfully incorporated them. In this study, we try to reveal the current status of coupling LTERs with environmental assessments and look at the challenges involved in improving this coupling through exploring the role that Chinese Ecological Research Network (CERN), the LTER of China, currently plays in regional environment assessments. A review of official protocols and standards, regional assessments and CERN researches related to ecosystems and environment shows that there is great potential for coupling CERN with environment assessments. However in practice, CERN does not currently play the expected role. Remote sensing and irregular inventory data are still the main data sources currently used in regional assessments. Several causes led to the present situation: (1) insufficient cross-site research and failure to scale up site-level variables to the regional scale; (2) data barriers resulting from incompatible protocols and low data usability due to lack of data assimilation and scaling; and (3) absence of indicators relevant to human activities in existing monitoring protocols. For these reasons, enhancing cross-site monitoring and research, data assimilation and scaling up are critical steps required to improve coupling of LTER with environmental assessments. Site-focused long-term monitoring should be combined with wide-scale ground surveys and remote sensing to establish an effective connection between different environmental monitoring platforms for regional assessments. It is also necessary to revise the current monitoring protocols to include human activities and their impacts on the ecosystem, or change the LTERs into Long

  15. Development and Validation of an Instrument for Assessing Mathematics Classroom Environment in Tertiary Institutions

    ERIC Educational Resources Information Center

    Yin, Hongbiao; Lu, Genshu

    2014-01-01

    This report describes the development and validation of an instrument, the University Mathematics Classroom Environment Questionnaire (UMCEQ), for assessing the mathematics classroom environment in tertiary institutions in China. Through the use of multiple methods, including exploratory and confirmatory factor analyses, on two independent samples…

  16. Assessment of effective radiation dose of an extremity CBCT, MSCT and conventional X ray for knee area using MOSFET dosemeters.

    PubMed

    Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

    2013-12-01

    The objective of this study was to assess and compare the organ and effective doses in the knee area resulting from different commercially available multislice computed tomography devices (MSCT), one cone beam computed tomography device (CBCT) and one conventional X-ray radiography device using MOSFET dosemeters and an anthropomorphic RANDO knee phantom. Measurements of the MSCT devices resulted in effective doses ranging between 27 and 48 µSv. The CBCT measurements resulted in an effective dose of 12.6 µSv. The effective doses attained using the conventional radiography device were 1.8 µSv for lateral and 1.2 µSv for anterior-posterior projections. The effective dose resulting from conventional radiography was considerably lower than those recorded for the CBCT and MSCT devices. The MSCT effective dose results were two to four times higher than those measured on the CBCT device. This study demonstrates that CBCT can be regarded as a potential low-dose 3D imaging technique for knee examinations.

  17. On use of the multistage dose-response model for assessing laboratory animal carcinogenicity

    PubMed Central

    Nitcheva, Daniella; Piegorsch, Walter W.; West, R. Webster

    2007-01-01

    We explore how well a statistical multistage model describes dose-response patterns in laboratory animal carcinogenicity experiments from a large database of quantal response data. The data are collected from the U.S. EPA’s publicly available IRIS data warehouse and examined statistically to determine how often higher-order values in the multistage predictor yield significant improvements in explanatory power over lower-order values. Our results suggest that the addition of a second-order parameter to the model only improves the fit about 20% of the time, while adding even higher-order terms apparently does not contribute to the fit at all, at least with the study designs we captured in the IRIS database. Also included is an examination of statistical tests for assessing significance of higher-order terms in a multistage dose-response model. It is noted that bootstrap testing methodology appears to offer greater stability for performing the hypothesis tests than a more-common, but possibly unstable, “Wald” test. PMID:17490794

  18. Assessment in Immersive Virtual Environments: Cases for Learning, of Learning, and as Learning

    ERIC Educational Resources Information Center

    Code, Jillianne; Zap, Nick

    2017-01-01

    The key to education reform lies in exploring alternative forms of assessment. Alternative performance assessments provide a more valid measure than multiple-choice tests of students' conceptual understanding and higher-level skills such as problem solving and inquiry. Advances in game-based and virtual environment technologies are creating new…

  19. 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

  20. Collective doses to man from dumping of radioactive waste in the Arctic Seas.

    PubMed

    Nielsen, S P; Iosjpe, M; Strand, P

    1997-08-25

    A box model for the dispersion of radionuclides in the marine environment covering the Arctic Ocean and the North Atlantic Ocean has been constructed. Collective doses from ingestion pathways have been calculated from unit releases of the radionuclides 3H, 60Co, 63Ni, 90Sr, 129I, 137Cs, 239Pu and 241Am into a fjord on the east coast of NovayaZemlya. The results show that doses for the shorter-lived radionuclides (e.g. 137Cs) are derived mainly from seafood production in the Barents Sea. Doses from the longer-lived radionuclides (e.g. 239Pu) are delivered through marine produce further away from the Arctic Ocean. Collective doses were calculated for two release scenarios, both of which are based on information of the dumping of radioactive waste in the Barents and Kara Seas by the former Soviet Union and on preliminary information from the International Arctic Sea Assessment Programme. A worst-case scenario was assumed according to which all radionuclides in liquid and solid radioactive waste were available for dispersion in the marine environment at the time of dumping. Release of radionuclides from spent nuclear fuel was assumed to take place by direct corrosion of the fuel ignoring the barriers that prevent direct contact between the fuel and the seawater. The second scenario selected assumed that releases of radionuclides from spent nuclear fuel do not occur until after failure of the protective barriers. All other liquid and solid radioactive waste was assumed to be available for dispersion at the time of discharge in both scenarios. The estimated collective dose for the worst-case scenario was about 9 manSv and that for the second scenario was about 3 manSv. In both cases, 137Cs is the radionuclide predicted to dominate the collective doses as well as the peak collective dose rates.

  1. Agreement between quantitative microbial risk assessment and epidemiology at low doses during waterborne outbreaks of protozoan disease

    USDA-ARS?s Scientific Manuscript database

    Quantitative microbial risk assessment (QMRA) is a valuable complement to epidemiology for understanding the health impacts of waterborne pathogens. The approach works by extrapolating available data in two ways. First, dose-response data are typically extrapolated from feeding studies, which use ...

  2. Fully automated bone mineral density assessment from low-dose chest CT

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Gonzalez, Jessica; Zulueta, Javier; de-Torres, Juan P.; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2018-02-01

    A fully automated system is presented for bone mineral density (BMD) assessment from low-dose chest CT (LDCT). BMD assessment is central in the diagnosis and follow-up therapy monitoring of osteoporosis, which is characterized by low bone density and is estimated to affect 12.3 million US population aged 50 years or older, creating tremendous social and economic burdens. BMD assessment from DXA scans (BMDDXA) is currently the most widely used and gold standard technique for the diagnosis of osteoporosis and bone fracture risk estimation. With the recent large-scale implementation of annual lung cancer screening using LDCT, great potential emerges for the concurrent opportunistic osteoporosis screening. In the presented BMDCT assessment system, each vertebral body is first segmented and labeled with its anatomical name. Various 3D region of interest (ROI) inside the vertebral body are then explored for BMDCT measurements at different vertebral levels. The system was validated using 76 pairs of DXA and LDCT scans of the same subject. Average BMDDXA of L1-L4 was used as the reference standard. Statistically significant (p-value < 0.001) strong correlation is obtained between BMDDXA and BMDCT at all vertebral levels (T1 - L2). A Pearson correlation of 0.857 was achieved between BMDDXA and average BMDCT of T9-T11 by using a 3D ROI taking into account of both trabecular and cortical bone tissue. These encouraging results demonstrate the feasibility of fully automated quantitative BMD assessment and the potential of opportunistic osteoporosis screening with concurrent lung cancer screening using LDCT.

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

    PubMed

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

    2017-01-01

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

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

    PubMed Central

    Krstic, D.; Nikezic, D.

    2017-01-01

    Radiotherapy is a common cancer treatment module, where a certain amount of dose will be delivered to the targeted organ. This is achieved usually by photons generated by linear accelerator units. However, radiation scattering within the patient’s body and the surrounding environment will lead to dose dispersion to healthy tissues which are not targets of the primary radiation. Determination of the dispersed dose would be important for assessing the risk and biological consequences in different organs or tissues. In the present work, the concept of conversion coefficient (F) of the dispersed dose was developed, in which F = (Dd/Dt), where Dd was the dispersed dose in a non-targeted tissue and Dt is the absorbed dose in the targeted tissue. To quantify Dd and Dt, a comprehensive model was developed using the Monte Carlo N-Particle (MCNP) package to simulate the linear accelerator head, the human phantom, the treatment couch and the radiotherapy treatment room. The present work also demonstrated the feasibility and power of parallel computing through the use of the Message Passing Interface (MPI) version of MCNP5. PMID:28362837

  5. Implementation of ionizing radiation environment requirements for Space Station

    NASA Technical Reports Server (NTRS)

    Boeder, Paul A.; Watts, John W.

    1993-01-01

    Proper functioning of Space Station hardware requires that the effects of high-energy ionizing particles from the natural environment and (possibly) from man-made sources be considered during design. At the Space Station orbit of 28.5-deg inclination and 330-440 km altitude, geomagnetically trapped protons and electrons contribute almost all of the dose, while galactic cosmic rays and anomalous cosmic rays may produce Single Event Upsets (SEUs), latchups, and burnouts of microelectronic devices. Implementing ionizing radiation environment requirements for Space Station has been a two part process, including the development of a description of the environment for imposing requirements on the design and the development of a control process for assessing how well the design addresses the effects of the ionizing radiation environment. We will review both the design requirements and the control process for addressing ionizing radiation effects on Space Station.

  6. Virtual reality based adaptive dose assessment method for arbitrary geometries in nuclear facility decommissioning.

    PubMed

    Liu, Yong-Kuo; Chao, Nan; Xia, Hong; Peng, Min-Jun; Ayodeji, Abiodun

    2018-05-17

    This paper presents an improved and efficient virtual reality-based adaptive dose assessment method (VRBAM) applicable to the cutting and dismantling tasks in nuclear facility decommissioning. The method combines the modeling strength of virtual reality with the flexibility of adaptive technology. The initial geometry is designed with the three-dimensional computer-aided design tools, and a hybrid model composed of cuboids and a point-cloud is generated automatically according to the virtual model of the object. In order to improve the efficiency of dose calculation while retaining accuracy, the hybrid model is converted to a weighted point-cloud model, and the point kernels are generated by adaptively simplifying the weighted point-cloud model according to the detector position, an approach that is suitable for arbitrary geometries. The dose rates are calculated with the Point-Kernel method. To account for radiation scattering effects, buildup factors are calculated with the Geometric-Progression formula in the fitting function. The geometric modeling capability of VRBAM was verified by simulating basic geometries, which included a convex surface, a concave surface, a flat surface and their combination. The simulation results show that the VRBAM is more flexible and superior to other approaches in modeling complex geometries. In this paper, the computation time and dose rate results obtained from the proposed method were also compared with those obtained using the MCNP code and an earlier virtual reality-based method (VRBM) developed by the same authors. © 2018 IOP Publishing Ltd.

  7. Is it useful to assess annual effective doses that are less than 100 mSv?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Strom, Daniel J.; Cameron, John R.

    It is useful to assess annual effective doses less than 100 mSv. Beyond the''score-keeping'' needs of regulatory compliance, there are at least seven other valid reasons for performing personnel monitoring, many of which fall into the category of''no news is good news,'' or more aptly,''null news, as long as you can prove it, is good news.'' These are performance measures for contractual compliance, diagnosis of problems with radiation protection programs, health surveillance and occupational epidemiology, prevention of and support for litigation, demonstration of management commitment and safety, worker counseling, ensuring peace of mind. Furthermore, it is shown that there ismore » very reasonable expectation that detriment may be associated with doses smaller than 100 mSv per year.« less

  8. Assessing the Consumer Food Environment in Restaurants by Neighbourhood Distress Level across Saskatoon, Saskatchewan.

    PubMed

    Wang, Jin; Engler-Stringer, Rachel; Muhajarine, Nazeem

    2016-03-01

    To assess the consumer food environment in restaurants in Saskatoon, using the Nutrition Environment Measures Survey for Restaurants (NEMS-R), to examine differences by neighbourhood distress level and to reflect on the need for further refinement of the assessment of restaurant consumer food environments. Neighbourhoods were classified as low, middle, or high distress level based on the socioeconomic indicators (income, employment, and education) in the Material Deprivation Index. Differences in restaurant consumer food environments, indicated by mean NEMS-R total and sub-scores, were examined by various restaurant categories and by varying neighbourhood distress levels. Chain coffee shops and pita and sandwich restaurants had higher NEMS-R totals and "Healthy Entrées" sub-scores; however, burger and chicken restaurants and pizza restaurants had more barriers to healthful eating. Although restaurants in lower distress level neighbourhoods generally rated healthier (higher NEMS-R scores), only a few measures (such as "Facilitators" and "Barriers") significantly differed by neighbourhood distress level. The findings highlight the importance of developing interventions to improve restaurant consumer food environments, especially in neighbourhoods with higher distress levels. The results suggest that reliable measures of the consumer food environment could be developed beginning with what can be measured by NEMS-R.

  9. The Martian surface radiation environment - a comparison of models and MSL/RAD measurements

    NASA Astrophysics Data System (ADS)

    Matthiä, Daniel; Ehresmann, Bent; Lohf, Henning; Köhler, Jan; Zeitlin, Cary; Appel, Jan; Sato, Tatsuhiko; Slaba, Tony; Martin, Cesar; Berger, Thomas; Boehm, Eckart; Boettcher, Stephan; Brinza, David E.; Burmeister, Soenke; Guo, Jingnan; Hassler, Donald M.; Posner, Arik; Rafkin, Scot C. R.; Reitz, Günther; Wilson, John W.; Wimmer-Schweingruber, Robert F.

    2016-03-01

    Context: The Radiation Assessment Detector (RAD) on the Mars Science Laboratory (MSL) has been measuring the radiation environment on the surface of Mars since August 6th 2012. MSL-RAD is the first instrument to provide detailed information about charged and neutral particle spectra and dose rates on the Martian surface, and one of the primary objectives of the RAD investigation is to help improve and validate current radiation transport models. Aims: Applying different numerical transport models with boundary conditions derived from the MSL-RAD environment the goal of this work was to both provide predictions for the particle spectra and the radiation exposure on the Martian surface complementing the RAD sensitive range and, at the same time, validate the results with the experimental data, where applicable. Such validated models can be used to predict dose rates for future manned missions as well as for performing shield optimization studies. Methods: Several particle transport models (GEANT4, PHITS, HZETRN/OLTARIS) were used to predict the particle flux and the corresponding radiation environment caused by galactic cosmic radiation on Mars. From the calculated particle spectra the dose rates on the surface are estimated. Results: Calculations of particle spectra and dose rates induced by galactic cosmic radiation on the Martian surface are presented. Although good agreement is found in many cases for the different transport codes, GEANT4, PHITS, and HZETRN/OLTARIS, some models still show large, sometimes order of magnitude discrepancies in certain particle spectra. We have found that RAD data is helping to make better choices of input parameters and physical models. Elements of these validated models can be applied to more detailed studies on how the radiation environment is influenced by solar modulation, Martian atmosphere and soil, and changes due to the Martian seasonal pressure cycle. By extending the range of the calculated particle spectra with respect to

  10. A Direct Assessment of “Obesogenic” Built Environments: Challenges and Recommendations

    PubMed Central

    Gasevic, Danijela; Vukmirovich, Ina; Yusuf, Salim; Teo, Koon; Chow, Clara; Dagenais, Gilles; Lear, Scott A.

    2011-01-01

    This paper outlines the challenges faced during direct built environment (BE) assessments of 42 Canadian communities of various income and urbanization levels. In addition, we recommend options for overcoming such challenges during BE community assessments. Direct BE assessments were performed utilizing two distinct audit methods: (1) modified version of Irvine-Minnesota Inventory in which a paper version of an audit tool was used to assess BE features and (2) a Physical Activity and Nutrition Features audit tool, where the presence and positions of all environmental features of interest were recorded using a Global-Positioning-System (GPS) unit. This paper responds to the call for the need of creators and users of environmental audit tools to share experiences regarding the usability of tools for BE assessments. The outlined BE assessment challenges plus recommendations for overcoming them can help improve and refine the existing audit tools and aid researchers in future assessments of the BE. PMID:22174727

  11. 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

  12. An atmospheric vulnerability assessment framework for environment management and protection based on CAMx.

    PubMed

    Zhang, Yang; Shen, Jing; Li, Yu

    2018-02-01

    This paper presents an atmospheric vulnerability assessment framework based on CAMx that should be helpful to assess potential impacts of changes in human, atmospheric environment, and social economic elements of atmospheric vulnerability. It is also a useful and effective tool that can provide policy-guidance for environmental protection and management to reduce the atmospheric vulnerability. The developed framework was applied to evaluate the atmospheric environment vulnerability of 13 cities in the Beijing-Tianjin-Hebei (BTH) region for verification. The results indicated that regional disparity of the atmospheric vulnerability existed in the study site. More specifically, the central and southern regions show more atmospheric environment vulnerability than the northern regions. The impact factors of atmospheric environment vulnerability in the BTH region mainly derived from increasing population press, frequently unfavorable meteorological conditions, extensive economic growth of secondary industry, increased environmental pollution, and accelerating population aging. The framework shown in this paper is an interpretative and heuristic tool for a better understanding of atmospheric vulnerability. This framework can also be replicated at different spatial and temporal scales using context-specific datasets to straightly support environmental managers with decision-making. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Web-Based Virtual Environments for Facilitating Assessment of L2 Oral Communication Ability

    ERIC Educational Resources Information Center

    Ockey, Gary J.; Gu, Lin; Keehner, Madeleine

    2017-01-01

    A growing number of stakeholders argue for the use of second language (L2) speaking assessments that measure the ability to orally communicate in real time. A Web-based virtual environment (VE) that allows live voice communication among individuals may have potential for aiding in delivering such assessments. While off-the-shelf voice…

  14. 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.

  15. 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

  16. Implications of free breathing motion assessed by 4D-computed tomography on the delivered dose in radiotherapy for esophageal cancer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duma, Marciana Nona, E-mail: Marciana.Duma@mri.tum.de; Berndt, Johannes; Rondak, Ina-Christine

    2015-01-01

    The aim of this study was to assess the effect of breathing motion on the delivered dose in esophageal cancer 3-dimensional (3D)-conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and volumetric modulated arc therapy (VMAT). We assessed 16 patients with esophageal cancer. All patients underwent 4D-computed tomography (4D-CT) for treatment planning. For each of the analyzed patients, 1 3D-CRT, 1 IMRT, and 1 VMAT (RapidArc—RA) plan were calculated. Each of the 3 initial plans was recalculated on the 4D-CT (for the maximum free inspiration and maximum free expiration) to assess the effect of breathing motion. We assessed the minimum dose (D{sub min})more » and mean dose (D{sub mean}) to the esophagus within the planning target volume, the volume changes of the lungs, the D{sub mean} and the total lung volume receiving at least 40 Gy (V{sub 40}), and the V{sub 30}, V{sub 20}, V{sub 10}, and V{sub 5}. For the heart we assessed the D{sub mean} and the V{sub 25}. Over all techniques and all patients the change in D{sub mean} as compared with the planned D{sub mean} (planning CT [PCT]) to the esophagus was 0.48% in maximum free inspiration (CT-insp) and 0.55% in maximum free expiration (CT-exp). The D{sub min} CT-insp change was 0.86% and CT-exp change was 0.89%. The D{sub mean} change of the lungs (heart) was in CT-insp 1.95% (2.89%) and 3.88% (2.38%) in CT-exp. In all, 4 patients had a clinically relevant change of the dose (≥ 5% D{sub mean} to the heart and the lungs) between inspiration and expiration. These patients had a very cranially or caudally situated tumor. There are no relevant differences in the delivered dose to the regions of interest among the 3 techniques. Breathing motion management could be considered to achieve a better sparing of the lungs or heart in patients with cranially or caudally situated tumors.« less

  17. Transcriptomic Dose-Response Analysis for Mode of Action ...

    EPA Pesticide Factsheets

    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 with minimal replication. Thus, they were not useful in understanding health risks at environmentally-relevant doses. Until the past decade, application of toxicogenomics in dose response assessment and determination of chemical mode of action has been limited. New transcriptomic biomarkers have evolved to detect chemical hazards in multiple tissues together with pathway methods to study biological effects across the full dose response range and critical time course. Comprehensive low dose datasets are now available and with the use of transcriptomic benchmark dose estimation techniques within a mode of action framework, the ability to incorporate informative genomic data into human health risk assessment has substantially improved. The key advantage to applying transcriptomic technology to risk assessment is both the sensitivity and comprehensive examination of direct and indirect molecular changes that lead to adverse outcomes. Book Chapter with topic on future application of toxicogenomics technologies for MoA and risk assessment

  18. SOME PROBLEMS OF "SAFE DOSE" ESTIMATION

    EPA Science Inventory

    In environmental carcinogenic risk assessment, the usually defined "safe doses" appear subjective in some sense. n this paper a method of standardizing "safe doses" based on some objective parameters is introduced and a procedure of estimating safe doses under the competing risks...

  19. Considerations on the calibration of small thermoluminescent dosimeters used for measurement of beta particle absorbed doses in liquid environments.

    PubMed

    Demidecki, A J; Williams, L E; Wong, J Y; Wessels, B W; Yorke, E D; Strandh, M; Strand, S E

    1993-01-01

    An investigation has been carried out on the factors which affect the absolute calibration of thermoluminescent dosimeters (TLDs) used in beta particle absorbed dose evaluations. Four effects on light output (LO) were considered: decay of detector sensitivity with time, finite TLD volume, dose linearity, and energy dependence. Most important of these was the decay of LO with time in culture medium, muscle tissue, and gels. This permanent loss of sensitivity was as large as an order of magnitude over a 21-day interval for the nominally 20-microns-thick disc-shaped CaSO4(Dy) TLDs in gel. Associated leaching of the dosimeter crystals out of the Teflon matrix was observed using scanning electron microscopy. Large channels leading from the outside environment into the TLDs were identified using SEM images. A possibility of batch dependence of fading was indicated. The second most important effect was the apparent reduction of light output due to finite size and increased specific gravity of the dosimeter (volume effect). We estimated this term by calculations as 10% in standard "mini" rods for beta particles from 90Y, but nearly a factor of 3 for 131I beta particles in the same geometry. No significant nonlinearity of the log (light output) with log (absorbed dose) over the range 0.05-20.00 Gy was discovered. Energy dependence of the LO was found to be not detectable, within measurement errors, over the range of 0.60-6.0 MeV mean energy electrons. With careful understanding of these effects, calibration via gel phantom would appear to be an acceptable strategy for mini TLDs used in beta absorbed dose evaluations in media.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. 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. © 2011 The Authors. Veterinary Dermatology. © 2011 ESVD and ACVD.

  1. Radiation Hormesis: Historical Perspective and Implications for Low-Dose Cancer Risk Assessment

    PubMed Central

    Vaiserman, Alexander M.

    2010-01-01

    Current guidelines for limiting exposure of humans to ionizing radiation are based on the linear-no-threshold (LNT) hypothesis for radiation carcinogenesis under which cancer risk increases linearly as the radiation dose increases. With the LNT model even a very small dose could cause cancer and the model is used in establishing guidelines for limiting radiation exposure of humans. A slope change at low doses and dose rates is implemented using an empirical dose and dose rate effectiveness factor (DDREF). This imposes usually unacknowledged nonlinearity but not a threshold in the dose-response curve for cancer induction. In contrast, with the hormetic model, low doses of radiation reduce the cancer incidence while it is elevated after high doses. Based on a review of epidemiological and other data for exposure to low radiation doses and dose rates, it was found that the LNT model fails badly. Cancer risk after ordinarily encountered radiation exposure (medical X-rays, natural background radiation, etc.) is much lower than projections based on the LNT model and is often less than the risk for spontaneous cancer (a hormetic response). Understanding the mechanistic basis for hormetic responses will provide new insights about both risks and benefits from low-dose radiation exposure. PMID:20585444

  2. Optimizing Scoring and Sampling Methods for Assessing Built Neighborhood Environment Quality in Residential Areas

    PubMed Central

    Adu-Brimpong, Joel; Coffey, Nathan; Ayers, Colby; Berrigan, David; Yingling, Leah R.; Thomas, Samantha; Mitchell, Valerie; Ahuja, Chaarushi; Rivers, Joshua; Hartz, Jacob; Powell-Wiley, Tiffany M.

    2017-01-01

    Optimization of existing measurement tools is necessary to explore links between aspects of the neighborhood built environment and health behaviors or outcomes. We evaluate a scoring method for virtual neighborhood audits utilizing the Active Neighborhood Checklist (the Checklist), a neighborhood audit measure, and assess street segment representativeness in low-income neighborhoods. Eighty-two home neighborhoods of Washington, D.C. Cardiovascular Health/Needs Assessment (NCT01927783) participants were audited using Google Street View imagery and the Checklist (five sections with 89 total questions). Twelve street segments per home address were assessed for (1) Land-Use Type; (2) Public Transportation Availability; (3) Street Characteristics; (4) Environment Quality and (5) Sidewalks/Walking/Biking features. Checklist items were scored 0–2 points/question. A combinations algorithm was developed to assess street segments’ representativeness. Spearman correlations were calculated between built environment quality scores and Walk Score®, a validated neighborhood walkability measure. Street segment quality scores ranged 10–47 (Mean = 29.4 ± 6.9) and overall neighborhood quality scores, 172–475 (Mean = 352.3 ± 63.6). Walk scores® ranged 0–91 (Mean = 46.7 ± 26.3). Street segment combinations’ correlation coefficients ranged 0.75–1.0. Significant positive correlations were found between overall neighborhood quality scores, four of the five Checklist subsection scores, and Walk Scores® (r = 0.62, p < 0.001). This scoring method adequately captures neighborhood features in low-income, residential areas and may aid in delineating impact of specific built environment features on health behaviors and outcomes. PMID:28282878

  3. Optimizing Scoring and Sampling Methods for Assessing Built Neighborhood Environment Quality in Residential Areas.

    PubMed

    Adu-Brimpong, Joel; Coffey, Nathan; Ayers, Colby; Berrigan, David; Yingling, Leah R; Thomas, Samantha; Mitchell, Valerie; Ahuja, Chaarushi; Rivers, Joshua; Hartz, Jacob; Powell-Wiley, Tiffany M

    2017-03-08

    Optimization of existing measurement tools is necessary to explore links between aspects of the neighborhood built environment and health behaviors or outcomes. We evaluate a scoring method for virtual neighborhood audits utilizing the Active Neighborhood Checklist (the Checklist), a neighborhood audit measure, and assess street segment representativeness in low-income neighborhoods. Eighty-two home neighborhoods of Washington, D.C. Cardiovascular Health/Needs Assessment (NCT01927783) participants were audited using Google Street View imagery and the Checklist (five sections with 89 total questions). Twelve street segments per home address were assessed for (1) Land-Use Type; (2) Public Transportation Availability; (3) Street Characteristics; (4) Environment Quality and (5) Sidewalks/Walking/Biking features. Checklist items were scored 0-2 points/question. A combinations algorithm was developed to assess street segments' representativeness. Spearman correlations were calculated between built environment quality scores and Walk Score ® , a validated neighborhood walkability measure. Street segment quality scores ranged 10-47 (Mean = 29.4 ± 6.9) and overall neighborhood quality scores, 172-475 (Mean = 352.3 ± 63.6). Walk scores ® ranged 0-91 (Mean = 46.7 ± 26.3). Street segment combinations' correlation coefficients ranged 0.75-1.0. Significant positive correlations were found between overall neighborhood quality scores, four of the five Checklist subsection scores, and Walk Scores ® ( r = 0.62, p < 0.001). This scoring method adequately captures neighborhood features in low-income, residential areas and may aid in delineating impact of specific built environment features on health behaviors and outcomes.

  4. Internal dose assessment of 210Po using biokinetic modeling and urinary excretion measurement.

    PubMed

    Li, Wei Bo; Gerstmann, Udo; Giussani, Augusto; Oeh, Uwe; Paretzke, Herwig G

    2008-02-01

    The mysterious death of Mr. Alexander Litvinenko who was most possibly poisoned by Polonium-210 ((210)Po) in November 2006 in London attracted the attention of the public to the kinetics, dosimetry and the risk of this high radiotoxic isotope in the human body. In the present paper, the urinary excretion of seven persons who were possibly exposed to traces of (210)Po was monitored. The values measured in the GSF Radioanalytical Laboratory are in the range of natural background concentration. To assess the effective dose received by those persons, the time-dependence of the organ equivalent dose and the effective dose after acute ingestion and inhalation of (210)Po were calculated using the biokinetic model for polonium (Po) recommended by the International Commission on Radiological Protection (ICRP) and the one recently published by Leggett and Eckerman (L&E). The daily urinary excretion to effective dose conversion factors for ingestion and inhalation were evaluated based on the ICRP and L&E models for members of the public. The ingestion (inhalation) effective dose per unit intake integrated over one day is 1.7 x 10(-8) (1.4 x 10(-7)) Sv Bq(-1), 2.0 x 10(-7) (9.6 x 10(-7)) Sv Bq(-1) over 10 days, 5.2 x 10(-7) (2.0 x 10(-6)) Sv Bq(-1) over 30 days and 1.0 x 10(-6) (3.0 x 10(-6)) Sv Bq(-1) over 100 days. The daily urinary excretions after acute ingestion (inhalation) of 1 Bq of (210)Po are 1.1 x 10(-3) (1.0 x 10(-4)) on day 1, 2.0 x 10(-3) (1.9 x 10(-4)) on day 10, 1.3 x 10(-3) (1.7 x 10(-4)) on day 30 and 3.6 x 10(-4) (8.3 x 10(-5)) Bq d(-1) on day 100, respectively. The resulting committed effective doses range from 2.1 x 10(-3) to 1.7 x 10(-2) mSv by an assumption of ingestion and from 5.5 x 10(-2) to 4.5 x 10(-1) mSv by inhalation. For the case of Mr. Litvinenko, the mean organ absorbed dose as a function of time was calculated using both the above stated models. The red bone marrow, the kidneys and the liver were considered as the critical organs. Assuming a

  5. eDrugCalc: an online self-assessment package to enhance medical students' drug dose calculation skills.

    PubMed

    McQueen, Daniel S; Begg, Michael J; Maxwell, Simon R J

    2010-10-01

    Dose calculation errors can cause serious life-threatening clinical incidents. We designed eDrugCalc as an online self-assessment tool to develop and evaluate calculation skills among medical students. We undertook a prospective uncontrolled study involving 1727 medical students in years 1-5 at the University of Edinburgh. Students had continuous access to eDrugCalc and were encouraged to practise. Voluntary self-assessment was undertaken by answering the 20 questions on six occasions over 30 months. Questions remained fixed but numerical variables changed so each visit required a fresh calculation. Feedback was provided following each answer. Final-year students had a significantly higher mean score in test 6 compared with test 1 [16.6, 95% confidence interval (CI) 16.2, 17.0 vs. 12.6, 95% CI 11.9, 13.4; n= 173, P < 0.0001 Wilcoxon matched pairs test] and made a median of three vs. seven errors. Performance was highly variable in all tests with 2.7% of final-year students scoring < 10/20 in test 6. Graduating students in 2009 (30 months' exposure) achieved significantly better scores than those in 2007 (only 6 months): mean 16.5, 95% CI 16.0, 17.0, n= 184 vs. 15.1, 95% CI 14.5, 15.6, n= 187; P < 0.0001, Mann-Whitney test. Calculations based on percentage concentrations and infusion rates were poorly performed. Feedback showed that eDrugCalc increased confidence in calculating doses and was highly rated as a learning tool. Medical student performance of dose calculations improved significantly after repeated exposure to an online formative dose-calculation package and encouragement to develop their numeracy. Further research is required to establish whether eDrugCalc reduces calculation errors made in clinical practice. © 2010 The Authors. British Journal of Clinical Pharmacology © 2010 The British Pharmacological Society.

  6. Space Radiation Environment Prediction for VLSI microelectronics devices onboard a LEO Satellite using OMERE-Trad Software

    NASA Astrophysics Data System (ADS)

    Sajid, Muhammad

    This tutorial/survey paper presents the assessment/determination of level of hazard/threat to emerging microelectronics devices in Low Earth Orbit (LEO) space radiation environment with perigee at 300 Km, apogee at 600Km altitude having different orbital inclinations to predict the reliability of onboard Bulk Built-In Current Sensor (BBICS) fabricated in 350nm technology node at OptMA Lab. UFMG Brazil. In this context, the various parameters for space radiation environment have been analyzed to characterize the ionizing radiation environment effects on proposed BBICS. The Space radiation environment has been modeled in the form of particles trapped in Van-Allen radiation belts(RBs), Energetic Solar Particles Events (ESPE) and Galactic Cosmic Rays (GCR) where as its potential effects on Device- Under-Test (DUT) has been predicted in terms of Total Ionizing Dose (TID), Single-Event Effects (SEE) and Displacement Damage Dose (DDD). Finally, the required mitigation techniques including necessary shielding requirements to avoid undesirable effects of radiation environment at device level has been estimated /determined with assumed standard thickness of Aluminum shielding. In order to evaluate space radiation environment and analyze energetic particles effects on BBICS, OMERE toolkit developed by TRAD was utilized.

  7. APPLICATION AND USE OF DOSE ESTIMATING EXPOSURE MODEL (DEEM) FOR DOSE COMPARISONS AFTER EXPOSURE TO TRICHLOROETHYLENE (TCE)

    EPA Science Inventory

    Route-to-route extrapolations are a crucial step in many risk assessments. Often the doses which result In toxicological end points in one route must be compared with doses resulting from typical environmental exposures by another route. In this case we used EPA's Dose Estimati...

  8. The current state of knowledge on the use of the benchmark dose concept in risk assessment.

    PubMed

    Sand, Salomon; Victorin, Katarina; Filipsson, Agneta Falk

    2008-05-01

    This review deals with the current state of knowledge on the use of the benchmark dose (BMD) concept in health risk assessment of chemicals. The BMD method is an alternative to the traditional no-observed-adverse-effect level (NOAEL) and has been presented as a methodological improvement in the field of risk assessment. The BMD method has mostly been employed in the USA but is presently given higher attention also in Europe. The review presents a number of arguments in favor of the BMD, relative to the NOAEL. In addition, it gives a detailed overview of the several procedures that have been suggested and applied for BMD analysis, for quantal as well as continuous data. For quantal data the BMD is generally defined as corresponding to an additional or extra risk of 5% or 10%. For continuous endpoints it is suggested that the BMD is defined as corresponding to a percentage change in response relative to background or relative to the dynamic range of response. Under such definitions, a 5% or 10% change can be considered as default. Besides how to define the BMD and its lower bound, the BMDL, the question of how to select the dose-response model to be used in the BMD and BMDL determination is highlighted. Issues of study design and comparison of dose-response curves and BMDs are also covered. Copyright (c) 2007 John Wiley & Sons, Ltd.

  9. Fully automated breast density assessment from low-dose chest CT

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Margolies, Laurie R.; Xie, Yiting; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

    2017-03-01

    Breast cancer is the most common cancer diagnosed among US women and the second leading cause of cancer death 1 . Breast density is an independent risk factor for breast cancer and more than 25 states mandate its reporting to patients as part of the lay mammogram report 2 . Recent publications have demonstrated that breast density measured from low-dose chest CT (LDCT) correlates well with that measured from mammograms and MRIs 3-4 , thereby providing valuable information for many women who have undergone LDCT but not recent mammograms. A fully automated framework for breast density assessment from LDCT is presented in this paper. The whole breast region is first segmented using an anatomy-orientated novel approach based on the propagation of muscle fronts for separating the fibroglandular tissue from the underlying muscles. The fibroglandular tissue regions are then identified from the segmented whole breast and the percentage density is calculated based on the volume ratio of the fibroglandular tissue to the local whole breast region. The breast region segmentation framework was validated with 1270 LDCT scans, with 96.1% satisfactory outcomes based on visual inspection. The density assessment was evaluated by comparing with BI-RADS density grades established by an experienced radiologist in 100 randomly selected LDCT scans of female subjects. The continuous breast density measurement was shown to be consistent with the reference subjective grading, with the Spearman's rank correlation 0.91 (p-value < 0.001). After converting the continuous density to categorical grades, the automated density assessment was congruous with the radiologist's reading in 91% cases.

  10. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MISCELLANEOUS GUIDANCE FOR THE DETERMINATION AND REPORTING OF NUCLEAR RADIATION DOSE FOR DOD PARTICIPANTS IN THE ATMOSPHERIC NUCLEAR TEST PROGRAM (1945-1962) § 218.4 Dose estimate reporting standards. The following minimum... of the radiation environment to which the veteran was exposed and shall include inhaled, ingested...

  11. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MISCELLANEOUS GUIDANCE FOR THE DETERMINATION AND REPORTING OF NUCLEAR RADIATION DOSE FOR DOD PARTICIPANTS IN THE ATMOSPHERIC NUCLEAR TEST PROGRAM (1945-1962) § 218.4 Dose estimate reporting standards. The following minimum... of the radiation environment to which the veteran was exposed and shall include inhaled, ingested...

  12. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MISCELLANEOUS GUIDANCE FOR THE DETERMINATION AND REPORTING OF NUCLEAR RADIATION DOSE FOR DOD PARTICIPANTS IN THE ATMOSPHERIC NUCLEAR TEST PROGRAM (1945-1962) § 218.4 Dose estimate reporting standards. The following minimum... of the radiation environment to which the veteran was exposed and shall include inhaled, ingested...

  13. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MISCELLANEOUS GUIDANCE FOR THE DETERMINATION AND REPORTING OF NUCLEAR RADIATION DOSE FOR DOD PARTICIPANTS IN THE ATMOSPHERIC NUCLEAR TEST PROGRAM (1945-1962) § 218.4 Dose estimate reporting standards. The following minimum... of the radiation environment to which the veteran was exposed and shall include inhaled, ingested...

  14. 32 CFR 218.4 - Dose estimate reporting standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MISCELLANEOUS GUIDANCE FOR THE DETERMINATION AND REPORTING OF NUCLEAR RADIATION DOSE FOR DOD PARTICIPANTS IN THE ATMOSPHERIC NUCLEAR TEST PROGRAM (1945-1962) § 218.4 Dose estimate reporting standards. The following minimum... of the radiation environment to which the veteran was exposed and shall include inhaled, ingested...

  15. Sustainability assessment for the transportation environment of Darjeeling, India.

    PubMed

    Nag, Dipanjan; Paul, Subrata Kr; Saha, Swati; Goswami, Arkopal K

    2018-05-01

    Darjeeling is an important tourist hill town of West Bengal, India. It suffers from an acute problem of transportation, particularly during its peak tourist seasons due to limited road space, inadequate public transport facilities and indiscriminate use of automobiles. This hill town was originally designed for a population of 10,000, but over the years, it has come face-to-face with rapid urbanization, a rising population of both tourists and residents and intensifying motor vehicle usage. These factors together are posing a threat to its transport environment. This study identifies the Sustainable Transport Indicators (STIs) available in the existing literature to identify the critical stretches using Analytical Hierarchy Process (AHP) based on experts' consensus. It was found that the experts placed emphasis on the mobility of the town, talking about vehicular impact on air pollution and encroachment of roads as the main issues affecting the sustainability of the transport environment. Thereafter, policy-level interventions have been suggested in accordance with the identified sustainability issues. We trust that other tourist hill towns with issues similar to Darjeeling could easily emulate the study methodology to assess their transport environment sustainability, or replicate on the lines of the recommended policy interventions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Optimization of the Temporal Pattern of Applied Radiation Dose: Implication for the Treatment of Prostate Cancer

    DTIC Science & Technology

    2009-03-01

    environment II.A: Characterization of dosimetry in IMRT radiobiological experiment phantom using TLDs and film. (7-10 mos.) Objectives: 1... dosimetry with TLDs and film. (8-10 mos.) 4. Analysis of measured dosimetry with TLDs and film compared to predicted dosimetry from treatment...cells were). Dosimetry in the phantom was assessed with film and monitor units were calculated accordingly to deliver the desired dose. Once in

  17. The home environment and toddler physical activity: an ecological momentary assessment study.

    PubMed

    Hager, E R; Tilton, N A; Wang, Y; Kapur, N C; Arbaiza, R; Merry, B C; Black, M M

    2017-02-01

    Physical activity (PA) promotion/obesity prevention in toddlerhood should include home environments. The aim of the study was to determine social/physical home environment factors associated with toddler PA using ecological momentary assessment (EMA, real-time data collection). Low-income mother-toddler dyads were recruited and given a handheld EMA device (53 random beeps followed by social/physical environment survey over 8 d). Simultaneously, PA was assessed via accelerometry (data extracted 15 min before/after response, average activity counts per minute). Linear mixed-effects models were used, adjusting for toddler age, urban/suburban residence and time of day; covariate moderating effects were examined; within-subjects and between-subjects findings were reported. PA was hypothesized to be greater when toddlers are outside (vs. inside), children are nearby (vs. alone), toddlers are interacting with their mothers (vs. not) and TV is off (vs. on). The final count was 2454 EMA/PA responses for 160 toddlers (mean age 20 months, range 12-31; 55% male, 66% Black and 54% urban). Associations with PA include (within subjects) the following: outside location (212 additional counts min -1 ), children nearby (153 additional counts min -1 ) and interacting with mother (321 additional counts min -1 ), compared with alternatives. Age was moderated by outside location/PA association (within subjects), with 90 additional counts min -1 per 3-month age group outside vs. inside. No between-subjects or television/PA associations were found. Home environment factors were associated with PA, including outside location, children nearby and mother interaction. EMA is a novel method, allowing identification of contextual factors associated with behaviours in natural environments. © 2015 World Obesity Federation.

  18. Preclinical Study of 68Ga-DOTATOC: Biodistribution Assessment in Syrian Rats and Evaluation of Absorbed Dose in Human Organs.

    PubMed

    Naderi, Mojdeh; Zolghadri, Samaneh; Yousefnia, Hassan; Ramazani, Ali; Jalilian, Amir Reza

    2016-01-01

    Gallium-68 DOTA-DPhe 1 -Tyr 3 -Octreotide ( 68 Ga-DOTATOC) has been applied by several European centers for the treatment of a variety of human malignancies. Nevertheless, definitive dosimetric data are yet unavailable. According to the Society of Nuclear Medicine and Molecular Imaging, researchers are investigating the safety and efficacy of this radiotracer to meet Food and Drug Administration requirements. The aim of this study was to introduce the optimized procedure for 68 Ga-DOTATOC preparation, using a novel germanium-68 ( 68 Ge)/ 68 Ga generator in Iran and evaluate the absorbed doses in numerous organs with high accuracy. The optimized conditions for preparing the radiolabeled complex were determined via several experiments by changing the ligand concentration, pH, temperature and incubation time. Radiochemical purity of the complex was assessed, using high-performance liquid chromatography and instant thin-layer chromatography. The absorbed dose of human organs was evaluated, based on biodistribution studies on Syrian rats via Radiation Absorbed Dose Assessment Resource Method. 68 Ga-DOTATOC was prepared with radiochemical purity of >98% and specific activity of 39.6 MBq/nmol. The complex demonstrated great stability at room temperature and in human serum at 37°C at least two hours after preparation. Significant uptake was observed in somatostatin receptor-positive tissues such as pancreatic and adrenal tissues (12.83 %ID/g and 0.91 %ID/g, respectively). Dose estimations in human organs showed that the pancreas, kidneys and adrenal glands received the maximum absorbed doses (0.105, 0.074 and 0.010 mGy/MBq, respectively). Also, the effective absorbed dose was estimated at 0.026 mSv/MBq for 68 Ga-DOTATOC. The obtained results showed that 68 Ga-DOTATOC can be considered as an effective agent for clinical PET imaging in Iran.

  19. Preclinical Study of 68Ga-DOTATOC: Biodistribution Assessment in Syrian Rats and Evaluation of Absorbed Dose in Human Organs

    PubMed Central

    Naderi, Mojdeh; Zolghadri, Samaneh; Yousefnia, Hassan; Ramazani, Ali; Jalilian, Amir Reza

    2016-01-01

    Objective(s): Gallium-68 DOTA-DPhe1-Tyr3-Octreotide (68Ga-DOTATOC) has been applied by several European centers for the treatment of a variety of human malignancies. Nevertheless, definitive dosimetric data are yet unavailable. According to the Society of Nuclear Medicine and Molecular Imaging, researchers are investigating the safety and efficacy of this radiotracer to meet Food and Drug Administration requirements. The aim of this study was to introduce the optimized procedure for 68Ga-DOTATOC preparation, using a novel germanium-68 (68Ge)/68Ga generator in Iran and evaluate the absorbed doses in numerous organs with high accuracy. Methods: The optimized conditions for preparing the radiolabeled complex were determined via several experiments by changing the ligand concentration, pH, temperature and incubation time. Radiochemical purity of the complex was assessed, using high-performance liquid chromatography and instant thin-layer chromatography. The absorbed dose of human organs was evaluated, based on biodistribution studies on Syrian rats via Radiation Absorbed Dose Assessment Resource Method. Results: 68Ga-DOTATOC was prepared with radiochemical purity of >98% and specific activity of 39.6 MBq/nmol. The complex demonstrated great stability at room temperature and in human serum at 37°C at least two hours after preparation. Significant uptake was observed in somatostatin receptor-positive tissues such as pancreatic and adrenal tissues (12.83 %ID/g and 0.91 %ID/g, respectively). Dose estimations in human organs showed that the pancreas, kidneys and adrenal glands received the maximum absorbed doses (0.105, 0.074 and 0.010 mGy/MBq, respectively). Also, the effective absorbed dose was estimated at 0.026 mSv/MBq for 68Ga-DOTATOC. Conclusion: The obtained results showed that 68Ga-DOTATOC can be considered as an effective agent for clinical PET imaging in Iran. PMID:27904870

  20. A phase I study to assess the single and multiple dose pharmacokinetics of THC/CBD oromucosal spray.

    PubMed

    Stott, C G; White, L; Wright, S; Wilbraham, D; Guy, G W

    2013-05-01

    A Phase I study to assess the single and multipledose pharmacokinetics (PKs) and safety and tolerability of oromucosally administered Δ(9)-tetrahydrocannabinol (THC)/cannabidiol (CBD) spray, an endocannabinoid system modulator, in healthy male subjects. Subjects received either single doses of THC/CBD spray as multiple sprays [2 (5.4 mg THC and 5.0 mg CBD), 4 (10.8 mg THC and 10.0 mg CBD) or 8 (21.6 mg THC and 20.0 mg CBD) daily sprays] or multiple doses of THC/CBD spray (2, 4 or 8 sprays once daily) for nine consecutive days, following fasting for a minimum of 10 h overnight prior to each dosing. Plasma samples were analyzed by gas chromatography-mass spectrometry for CBD, THC, and its primary metabolite 11-hydroxy-THC, and various PK parameters were investigated. Δ(9)-Tetrahydrocannabinol and CBD were rapidly absorbed following single-dose administration. With increasing single and multiple doses of THC/CBD spray, the mean peak plasma concentration (Cmax) increased for all analytes. There was evidence of dose-proportionality in the single but not the multiple dosing data sets. The bioavailability of THC was greater than CBD at single and multiple doses, and there was no evidence of accumulation for any analyte with multiple dosing. Inter-subject variability ranged from moderate to high for all PK parameters in this study. The time to peak plasma concentration (Tmax) was longest for all analytes in the eight spray group, but was similar in the two and four spray groups. THC/CBD spray was well-tolerated in this study and no serious adverse events were reported. The mean Cmax values (<12 ng/mL) recorded in this study were well below those reported in patients who smoked/inhaled cannabis, which is reassuring since elevated Cmax values are linked to significant psychoactivity. There was also no evidence of accumulation on repeated dosing.

  1. Organ dose assessment in pediatric fluoroscopy and CT via a tomographic computational phantom of the newborn patient

    NASA Astrophysics Data System (ADS)

    Staton, Robert J.

    Of the various types of imaging modalities used in pediatric radiology, fluoroscopy and computed tomography (CT) have the highest associated radiation dose. While these examinations are commonly used for pediatric patients, little data exists on the magnitude of the organ and effective dose values for these procedures. Calculation of these dose values is necessary because of children's increased sensitivity to radiation and their long life expectancy for which to express radiation's latent effects. In this study, a newborn tomographic phantom has been implemented in a radiation transport code to evaluate organ and effective doses for newborn patients in commonly performed fluoroscopy and CT examinations. Organ doses were evaluated for voiding cystourethrogram (VCUG) fluoroscopy studies of infant patients. Time-sequence analysis was performed for videotaped VCUG studies of five different patients. Organ dose values were then estimated for each patient through Monte Carlo (MC) simulations. The effective dose values of the VCUG examination for five patients ranged from 0.6 mSv to 3.2 mSv, with a mean of 1.8 +/- 0.9 mSv. Organ doses were also assessed for infant upper gastrointestinal (UGI) fluoroscopy exams. The effective dose values of the UGI examinations for five patients ranged from 1.05 mSv to 5.92 mSv, with a mean of 2.90 +/- 1.97 mSv. MC simulations of helical multislice CT (MSCT) exams were also completed using, the newborn tomographic phantom and a stylized newborn phantom. The helical path of the source, beam shaping filter, beam profile, patient table, were all included in the MC simulations of the helical MSCT scanner. Organ doses and effective doses and their dependence on scan parameters were evaluated for newborn patients. For all CT scans, the effective dose was found to range approximately 1-13 mSv, with the largest values occurring for CAP scans. Tube current modulation strategies to reduce patient dose were also evaluated for newborn patients

  2. Assessment of phase based dose modulation for improved dose efficiency in cardiac CT on an anthropomorphic motion phantom

    NASA Astrophysics Data System (ADS)

    Budde, Adam; Nilsen, Roy; Nett, Brian

    2014-03-01

    State of the art automatic exposure control modulates the tube current across view angle and Z based on patient anatomy for use in axial full scan reconstructions. Cardiac CT, however, uses a fundamentally different image reconstruction that applies a temporal weighting to reduce motion artifacts. This paper describes a phase based mA modulation that goes beyond axial and ECG modulation; it uses knowledge of the temporal view weighting applied within the reconstruction algorithm to improve dose efficiency in cardiac CT scanning. Using physical phantoms and synthetic noise emulation, we measure how knowledge of sinogram temporal weighting and the prescribed cardiac phase can be used to improve dose efficiency. First, we validated that a synthetic CT noise emulation method produced realistic image noise. Next, we used the CT noise emulation method to simulate mA modulation on scans of a physical anthropomorphic phantom where a motion profile corresponding to a heart rate of 60 beats per minute was used. The CT noise emulation method matched noise to lower dose scans across the image within 1.5% relative error. Using this noise emulation method to simulate modulating the mA while keeping the total dose constant, the image variance was reduced by an average of 11.9% on a scan with 50 msec padding, demonstrating improved dose efficiency. Radiation dose reduction in cardiac CT can be achieved while maintaining the same level of image noise through phase based dose modulation that incorporates knowledge of the cardiac reconstruction algorithm.

  3. A MULTIMODEL APPROACH FOR CALCULATING BENCHMARK DOSE

    EPA Science Inventory


    A Multimodel Approach for Calculating Benchmark Dose
    Ramon I. Garcia and R. Woodrow Setzer

    In the assessment of dose response, a number of plausible dose- response models may give fits that are consistent with the data. If no dose response formulation had been speci...

  4. 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.

  5. Dose in x-ray computed tomography

    NASA Astrophysics Data System (ADS)

    Kalender, Willi A.

    2014-02-01

    Radiation dose in x-ray computed tomography (CT) has become a topic of high interest due to the increasing numbers of CT examinations performed worldwide. This review aims to present an overview of current concepts for both scanner output metrics and for patient dosimetry and will comment on their strengths and weaknesses. Controversial issues such as the appropriateness of the CT dose index (CTDI) are discussed in detail. A review of approaches to patient dose assessment presently in practice, of the dose levels encountered and options for further dose optimization are also given and discussed. Patient dose assessment remains a topic for further improvement and for international consensus. All approaches presently in use are based on Monte Carlo (MC) simulations. Estimates for effective dose are established, but they are crude and not patient-specific; organ dose estimates are rarely available. Patient- and organ-specific dose estimates can be provided with adequate accuracy and independent of CTDI phantom measurements by fast MC simulations. Such information, in particular on 3D dose distributions, is important and helpful in optimization efforts. Dose optimization has been performed very successfully in recent years and even resulted in applications with effective dose values of below 1 mSv. In general, a trend towards lower dose values based on technical innovations has to be acknowledged. Effective dose values are down to clearly below 10 mSv on average, and there are a number of applications such as cardiac and pediatric CT which are performed routinely below 1 mSv on modern equipment.

  6. ASSESSING CHILDREN'S EXPOSURES TO PESTICIDES: AN IMPORTANT APPLICATION OF THE STOCHASTIC HUMAN EXPOSURE AND DOSE SIMULATION MODEL (SHEDS)

    EPA Science Inventory

    Accurately quantifying human exposures and doses of various populations to environmental pollutants is critical for the Agency to assess and manage human health risks. For example, the Food Quality Protection Act of 1996 (FQPA) requires EPA to consider aggregate human exposure ...

  7. Is Teacher Assessment Reliable or Valid for High School Students under a Web-Based Portfolio Environment?

    ERIC Educational Resources Information Center

    Chang, Chi-Cheng; Wu, Bing-Hong

    2012-01-01

    This study explored the reliability and validity of teacher assessment under a Web-based portfolio assessment environment (or Web-based teacher portfolio assessment). Participants were 72 eleventh graders taking the "Computer Application" course. The students perform portfolio creation, inspection, self- and peer-assessment using the Web-based…

  8. Quantitative assessment of the dose-response of alkylating agents in DNA repair proficient and deficient ames tester strains.

    PubMed

    Tang, Leilei; Guérard, Melanie; Zeller, Andreas

    2014-01-01

    Mutagenic and clastogenic effects of some DNA damaging agents such as methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) have been demonstrated to exhibit a nonlinear or even "thresholded" dose-response in vitro and in vivo. DNA repair seems to be mainly responsible for these thresholds. To this end, we assessed several mutagenic alkylators in the Ames test with four different strains of Salmonella typhimurium: the alkyl transferases proficient strain TA1535 (Ogt+/Ada+), as well as the alkyl transferases deficient strains YG7100 (Ogt+/Ada-), YG7104 (Ogt-/Ada+) and YG7108 (Ogt-/Ada-). The known genotoxins EMS, MMS, temozolomide (TMZ), ethylnitrosourea (ENU) and methylnitrosourea (MNU) were tested in as many as 22 concentration levels. Dose-response curves were statistically fitted by the PROAST benchmark dose model and the Lutz-Lutz "hockeystick" model. These dose-response curves suggest efficient DNA-repair for lesions inflicted by all agents in strain TA1535. In the absence of Ogt, Ada is predominantly repairing methylations but not ethylations. It is concluded that the capacity of alkyl-transferases to successfully repair DNA lesions up to certain dose levels contributes to genotoxicity thresholds. Copyright © 2013 Wiley Periodicals, Inc.

  9. Prototype Operational Advances for Atmospheric Radiation Dose Rate Specification

    NASA Astrophysics Data System (ADS)

    Tobiska, W. K.; Bouwer, D.; Bailey, J. J.; Didkovsky, L. V.; Judge, K.; Garrett, H. B.; Atwell, W.; Gersey, B.; Wilkins, R.; Rice, D.; Schunk, R. W.; Bell, D.; Mertens, C. J.; Xu, X.; Crowley, G.; Reynolds, A.; Azeem, I.; Wiltberger, M. J.; Wiley, S.; Bacon, S.; Teets, E.; Sim, A.; Dominik, L.

    2014-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. The coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has developed innovative, new space weather observations that will become part of the toolset that is transitioned into operational use. One prototype operational system for providing timely information about the effects of space weather is SET's Automated Radiation Measurements for Aerospace Safety (ARMAS) system. ARMAS will provide the "weather" of the radiation environment to improve aircraft crew and passenger safety. Through several dozen flights the ARMAS project has successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time via Iridium satellites, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. We are extending the dose measurement domain above commercial aviation altitudes into the stratosphere with a collaborative project organized by NASA's Armstrong Flight Research Center (AFRC) called Upper-atmospheric Space and Earth Weather eXperiment (USEWX). In USEWX we will be flying on the ER-2 high altitude aircraft a micro dosimeter for

  10. Policy Issues in Computer Education. Assessing the Cognitive Consequences of Computer Environments for Learning (ACCCEL).

    ERIC Educational Resources Information Center

    Linn, Marcia

    This paper analyzes the capabilities of the computer learning environment identified by the Assessing the Cognitive Consequences of Computer Environments for Learning (ACCCEL) Project, augments the analysis with experimental work, and discusses how schools can implement policies which provide for the maximum potential of computers. The ACCCEL…

  11. Integrated protection of humans and the environment: a view from Japan.

    PubMed

    Sakai, K

    2018-01-01

    Six and a half years after the accident at Fukushima Daiichi nuclear power plant, an area of existing exposure situation remains. One of the main concerns of people is the higher level of ionising radiation than before the accident, although this is not expected to have any discernible health effect. Since the accident, several 'abnormalities' in environmental organisms have been reported. It is still not clear if these abnormalities were induced by radiation. It appears that the impact of the released radioactivity has not been sufficient to threaten the maintenance of biological diversity, the conservation of species, or the health and status of natural habitats, which are the focus in environmental protection. This highlights a difference between the protection of humans and protection of the environment (individuals for humans and populations/species for the environment). The system for protection of the environment has been developed with a similar approach as the system for protection of humans. Reference Animals and Plants (RAPs) were introduced to connect exposure and doses in a way similar to that for Reference Male and Reference Female. RAPs can also be used as a tool to associate the level of radiation (dose rate) with the biological effects on an organism. A difference between the protection of humans and that of the environment was identified: an effect on humans is measured in terms of dose, and an effect on the environment is measured in terms of dose rate. In other words, protection criteria for humans are expressed in term of dose (as dose limits, dose constraints, and reference levels), whereas those for the environment are expressed in terms of dose rate (as derived consideration reference levels).

  12. Modelling PK/QT relationships from Phase I dose-escalation trials for drug combinations and developing quantitative risk assessments of clinically relevant QT prolongations.

    PubMed

    Sinclair, Karen; Kinable, Els; Grosch, Kai; Wang, Jixian

    2016-05-01

    In current industry practice, it is difficult to assess QT effects at potential therapeutic doses based on Phase I dose-escalation trials in oncology due to data scarcity, particularly in combinations trials. In this paper, we propose to use dose-concentration and concentration-QT models jointly to model the exposures and effects of multiple drugs in combination. The fitted models then can be used to make early predictions for QT prolongation to aid choosing recommended dose combinations for further investigation. The models consider potential correlation between concentrations of test drugs and potential drug-drug interactions at PK and QT levels. In addition, this approach allows for the assessment of the probability of QT prolongation exceeding given thresholds of clinical significance. The performance of this approach was examined via simulation under practical scenarios for dose-escalation trials for a combination of two drugs. The simulation results show that invaluable information of QT effects at therapeutic dose combinations can be gained by the proposed approaches. Early detection of dose combinations with substantial QT prolongation is evaluated effectively through the CIs of the predicted peak QT prolongation at each dose combination. Furthermore, the probability of QT prolongation exceeding a certain threshold is also computed to support early detection of safety signals while accounting for uncertainty associated with data from Phase I studies. While the prediction of QT effects is sensitive to the dose escalation process, the sensitivity and limited sample size should be considered when providing support to the decision-making process for further developing certain dose combinations. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Assessment of patient dose and radiogenic risks during endoscopic retrograde cholangiopancreatography.

    PubMed

    Sulieman, A; Elzaki, M; Alkhorayef, M; Babikir, E; Abuzaid, M; Dalton, A; Bradley, D

    2016-11-01

    Endoscopic retrograde cholangiopancreatography (ERCP) is an invasive technique that has been used for over 30 years in the diagnosis and management of pancreaticobiliary disorders. The objectives of this study were to evaluate the patient entrance surface air kerma doses (ESAK) and estimate the organ and effective doses during ERCP in three hospitals in Khartoum. A total of 55 patients were examined in three hospitals in Khartoum state, Sudan. Calibrated thermoluinescent dosimeters (TLD) were used to measure patients' ESAK. Organ and effective doses were estimated using National Radiological Protection Board (NRPB) software. The overall mean of ESAK for all ERCP procedures was 42.4mGy. The mean patient ESAK in Fedail (A), Soba (B) and Ibn sena (C) hospitals were 26.7mGy, 26.0mGy and 72.4mGy, respectively. The effective doses in three hospitals were 1.60, 1.56 and 2.67mSv in that order and the overall mean effective dose was 1.94mSv. Patient radiation doses vary widely among the hospitals. Patient ESAK is low compared to previous studies in the light of the current practice. Patient dose was decreased significantly in the last two decades. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Gating window dependency on scanned carbon-ion beam dose distribution and imaging dose for thoracoabdominal treatment.

    PubMed

    Mori, Shinichiro; Karube, Masataka; Yasuda, Shigeo; Yamamoto, Naoyoshi; Tsuji, Hiroshi; Kamada, Tadashi

    2017-06-01

    To explore the trade-off between dose assessment and imaging dose in respiratory gating with radiographic fluoroscopic imaging, we evaluated the relationship between dose assessment and fluoroscopic imaging dose in various gating windows, retrospectively. Four-dimensional (4D) CT images acquired for 10 patients with lung and liver tumours were used for 4D treatment planning for scanned carbon ion beam. Imaging dose from two oblique directions was calculated by the number of images multiplied by the air kerma per image. Necessary beam-on time was calculated from the treatment log file. Accumulated dose distribution was calculated. The gating window was defined as tumour position not respiratory phase and changed from 0-100% duty cycle on 4DCT. These metrics were individually evaluated for every case. For lung cases, sufficient dose conformation was achieved in respective gating windows [D 95 -clinical target volume (CTV) > 99%]. V 20 -lung values for 50%- and 30%-duty cycles were 2.5% and 6.0% of that for 100%-duty cycle. Maximum doses (cord/oesophagus) for 30%-duty cycle decreased 6.8%/7.4% to those for 100%-duty cycle. For liver cases, V 10 -liver values for 50%- and 30%-duty cycles were 9.4% and 12.8% of those for 100%-duty cycle, respectively. Maximum doses (cord/oesophagus) for 50%- and 30%-duty cycles also decreased 17.2%/19.3% and 24.6%/29.8% to those for 100%-duty cycle, respectively. Total imaging doses increased 43.5% and 115.8% for 50%- and 30%-duty cycles to that for the 100%-duty cycle. When normal tissue doses are below the tolerance level, the gating window should be expanded to minimize imaging dose and treatment time. Advances in knowledge: The skin dose from imaging might not be counterbalanced to the OAR dose; however, imaging dose is a particularly important factor.

  15. EPA's Benchmark Dose Modeling Software

    EPA Science Inventory

    The EPA developed the Benchmark Dose Software (BMDS) as a tool to help Agency risk assessors facilitate applying benchmark dose (BMD) method’s to EPA’s human health risk assessment (HHRA) documents. The application of BMD methods overcomes many well know limitations ...

  16. Nonmonotonic Dose Responses as They Apply to Estrogen, Androgen, and Thyroid Pathways and EPA Testing and Assessment Procedures

    EPA Pesticide Factsheets

    A state of the science document providing a judgment on the degree to which nonmonotonic dose-responses are evidenced in the scientific literature and to evaluate the extent to which they may impact U.S. EPA’s chemical testing and risk assessment.

  17. Pennsylvania College of Technology Personal Assessment of the College Environment (PACE) Survey Report, 1999.

    ERIC Educational Resources Information Center

    Pennsylvania Coll. of Technology, Williamsport. Office of Strategic Planning and Research.

    This report provides the results of the Personal Assessment of the College Environment (PACE) survey at the Pennsylvania College of Technology (Penn College). The instrument was designed by the National Initiative for Leadership and Institutional Effectiveness at North Carolina State University. The primary purpose of the survey is to assess the…

  18. Taiwan College Students' Self-Efficacy and Motivation of Learning in Online Peer Assessment Environments

    ERIC Educational Resources Information Center

    Tseng, Sheng-Chau; Tsai, Chin-Chung

    2010-01-01

    Online peer assessment is an innovative evaluation method that has caught both educators' and practitioners' attention in recent years. The purpose of this study was to develop relevant questionnaires for teachers to understand student self-efficacy and motivation in online peer assessment learning environments. A total of 205 college students…

  19. An airport community noise-impact assessment model

    NASA Technical Reports Server (NTRS)

    Deloach, R.

    1980-01-01

    A computer model was developed to assess the noise impact of an airport on the community which it serves. Assessments are made using the Fractional Impact Method by which a single number describes the community aircraft noise environment in terms of exposed population and multiple event noise level. The model is comprised of three elements: a conventional noise footprint model, a site specific population distribution model, and a dose response transfer function. The footprint model provides the noise distribution for a given aircraft operating scenario. This is combined with the site specific population distribution obtained from a national census data base to yield the number of residents exposed to a given level of noise. The dose response relationship relates noise exposure levels to the percentage of individuals highly annoyed by those levels.

  20. High-Dose Atomoxetine Treatment of ADHD in Youths with Limited Response to Standard Doses

    ERIC Educational Resources Information Center

    Kratochvil, Christopher J.; Michelson, David; Newcorn, Jeffrey H.; Weiss, Margaret D.; Busner, Joan; Moore, Rodney J.; Ruff, Dustin D.; Ramsey, Janet; Dickson, Ruth; Turgay, Atilla; Saylor, Keith E.; Luber, Stephen; Vaughan, Brigette; Allen, Albert J.

    2007-01-01

    Objective: To assess the utility and tolerability of higher than standard atomoxetine doses to treat attention-deficit/hyperactivity disorder (ADHD). Method: Two randomized, double-blind trials of atomoxetine nonresponders ages 6 to 16 years were conducted comparing continued treatment with same-dose atomoxetine to treatment using greater than…

  1. Neighborhood Quality and Attachment: Validation of the Revised Residential Environment Assessment Tool.

    PubMed

    Poortinga, Wouter; Calve, Tatiana; Jones, Nikki; Lannon, Simon; Rees, Tabitha; Rodgers, Sarah E; Lyons, Ronan A; Johnson, Rhodri

    2017-04-01

    Various studies have shown that neighborhood quality is linked to neighborhood attachment and satisfaction. However, most have relied upon residents' own perceptions rather than independent observations of the neighborhood environment. This study examines the reliability and validity of the revised Residential Environment Assessment Tool (REAT 2.0), an audit instrument covering both public and private spaces of the neighborhood environment. The research shows that REAT 2.0 is a reliable, easy-to-use instrument and that most underlying constructs can be validated against residents' own neighborhood perceptions. The convergent validity of the instrument, which was tested against digital map data, can be improved for a number of miscellaneous urban form items. The research further found that neighborhood attachment was significantly associated with the overall REAT 2.0 score. This association can mainly be attributed to the property-level neighborhood quality and natural elements components. The research demonstrates the importance of private spaces in the outlook of the neighborhood environment.

  2. Genotoxic effects of high dose rate X-ray and low dose rate gamma radiation in ApcMin/+ mice.

    PubMed

    Graupner, Anne; Eide, Dag M; Brede, Dag A; Ellender, Michele; Lindbo Hansen, Elisabeth; Oughton, Deborah H; Bouffler, Simon D; Brunborg, Gunnar; Olsen, Ann Karin

    2017-10-01

    Risk estimates for radiation-induced cancer in humans are based on epidemiological data largely drawn from the Japanese atomic bomb survivor studies, which received an acute high dose rate (HDR) ionising radiation. Limited knowledge exists about the effects of chronic low dose rate (LDR) exposure, particularly with respect to the application of the dose and dose rate effectiveness factor. As part of a study to investigate the development of colon cancer following chronic LDR vs. acute HDR radiation, this study presents the results of genotoxic effects in blood of exposed mice. CBAB6 F1 Apc +/+ (wild type) and Apc Min/+ mice were chronically exposed to estimated whole body absorbed doses of 1.7 or 3.2 Gy 60 Co-γ-rays at a LDR (2.2 mGy h -1 ) or acutely exposed to 2.6 Gy HDR X-rays (1.3 Gy min -1 ). Genotoxic endpoints assessed in blood included chromosomal damage (flow cytometry based micronuclei (MN) assay), mutation analyses (Pig-a gene mutation assay), and levels of DNA lesions (Comet assay, single-strand breaks (ssb), alkali labile sites (als), oxidized DNA bases). Ionising radiation (ca. 3 Gy) induced genotoxic effects dependent on the dose rate. Chromosomal aberrations (MN assay) increased 3- and 10-fold after chronic LDR and acute HDR, respectively. Phenotypic mutation frequencies as well as DNA lesions (ssb/als) were modulated after acute HDR but not after chronic LDR. The Apc Min/+ genotype did not influence the outcome in any of the investigated endpoints. The results herein will add to the scant data available on genotoxic effects following chronic LDR of ionising radiation. Environ. Mol. Mutagen. 58:560-569, 2017. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.

  3. Development of computational pregnant female and fetus models and assessment of radiation dose from positron-emitting tracers.

    PubMed

    Xie, Tianwu; Zaidi, Habib

    2016-12-01

    Molecular imaging using PET and hybrid (PET/CT and PET/MR) modalities nowadays plays a pivotal role in the clinical setting for diagnosis and staging, treatment response monitoring, and radiation therapy treatment planning of a wide range of oncologic malignancies. The developing embryo/fetus presents a high sensitivity to ionizing radiation. Therefore, estimation of the radiation dose delivered to the embryo/fetus and pregnant patients from PET examinations to assess potential radiation risks is highly praised. We constructed eight embryo/fetus models at various gestation periods with 25 identified tissues according to reference data recommended by the ICRP publication 89 representing the anatomy of the developing embryo/fetus. The developed embryo/fetus models were integrated into realistic anthropomorphic computational phantoms of the pregnant female and used for estimating, using Monte Carlo calculations, S-values of common positron-emitting radionuclides, organ absorbed dose, and effective dose of a number of positron-emitting labeled radiotracers. The absorbed dose is nonuniformly distributed in the fetus. The absorbed dose of the kidney and liver of the 8-week-old fetus are about 47.45 % and 44.76 % higher than the average absorbed dose of the fetal total body for all investigated radiotracers. For 18 F-FDG, the fetal effective doses are 2.90E-02, 3.09E-02, 1.79E-02, 1.59E-02, 1.47E-02, 1.40E-02, 1.37E-02, and 1.27E-02 mSv/MBq at the 8th, 10th, 15th, 20th, 25th, 30th, 35th, and 38th weeks of gestation, respectively. The developed pregnant female/fetus models matching the ICRP reference data can be exploited by dedicated software packages for internal and external dose calculations. The generated S-values will be useful to produce new standardized dose estimates to pregnant patients and embryo/fetus from a variety of positron-emitting labeled radiotracers.

  4. Internal dose assessment of 238U contaminated soils based on in-vitro gastrointestinal protocol

    NASA Astrophysics Data System (ADS)

    Perama, Yasmin Mohd Idris; Rashid, Nur Shahidah Abdul; Majid, Amran Ab.; Siong, Khoo Kok

    2017-01-01

    Human exposure to natural radioactive uranium has been a great interest as more industrial rapidly growing contributes to radiation risks. The aim of this case study was to determine the internal dose in humans incorporated with ingestion of 238U contaminated soils. A gastrointestinal analogue test was employed to simulate the human digestive tract. In-vitro approach via German DIN 19738 model was developed in order to estimate the internal exposure of 238U due to ingestion of different types of soils. Synthetic gastrointestinal fluids assay via in-vitro method were produced to determine the concentration of 238U in various soils using ICP-MS. Based on the results, concentration of 238U in BRIS, laterite, peat and alluvium soils were in ranged between (0.0061 ± 0.0057 - 0.0488 ± 0.0148) ppm and (0.0005 ± 0.0004 - 0.0046 ± 0.0007) ppm in gastric and gastrointestinal phase respectively. Types of soil compositions and pH medium were some of the factors that influence mobilization and solubility of 238U contaminanted soil into the digestive juices that resembles human gastrointestinal tract. For the purpose of internal dose assessment, the committed efective dose from 238U intake in soils ranged between 1.237 × 10-11 - 9.8993 × 10-11 Sv y-1 for gastric phase and 1.0184 × 10-12 - 9.3294 × 10-12 Sv y-1 for gastric-intestinal phase. The internal dose measurements from this study were much lower from the recommended values. Hence, ingestion of 238U contaminated soils would not be expected to pose major health risk to humans.

  5. Assessing dose of the representative person for the purpose of radiation protection of the public. ICRP publication 101. Approved by the Commission in September 2005.

    PubMed

    2006-01-01

    provision of dose coefficients for six age categories is not necessary in making prospective assessments of dose, given the inherent uncertainties usually associated with estimating dose to the public and with identification of the representative person. It now recommends the use of three age categories for estimating annual dose to the representative person for prospective assessments. These categories are 0-5 years (infant), 6-15 years (child), and 16-70 years (adult). For practical implementation of this recommendation, dose coefficients and habit data for a 1-year-old infant, a 10-year-old child, and an adult should be used to represent the three age categories. In a probabilistic assessment of dose, whether from a planned facility or an existing situation, the Commission recommends that the representative person should be defined such that the probability is less than about 5% that a person drawn at random from the population will receive a greater dose. If such an assessment indicates that a few tens of people or more could receive doses above the relevant constraint, the characteristics of these people need to be explored. If, following further analysis, it is shown that doses to a few tens of people are indeed likely to exceed the relevant dose constraint, actions to modify the exposure should be considered. The Commission recognises the role that stakeholders can play in identifying characteristics of the representative person. Involvement of stakeholders can significantly improve the quality, understanding, and acceptability of the characteristics of the representative person and the resulting estimated dose.

  6. Are College Students' Assessments of Threat Shaped by the Dangers of Their Childhood Environment?

    PubMed

    Sherman, Amanda K; Minich, Steven H; Langen, Tom A; Skufca, Joseph; Wilke, Andreas

    2016-07-01

    Humans internalize environmental cues of mortality risk at an early age, which influences subsequent risk perceptions and behavior. In this respect, an individual's current risk assessment may be viewed as an adaptive response to the dangers present within his or her early local environment. Here we examine the relationship between several variables indicating threat within an individual's early environment (e.g., prevalence of violent and property crimes, registered sex offenders) and their perception of crime risk within both the childhood and current adult environments. We recruited a group of 657 students who hail from diverse geographic backgrounds to provide the zip code location of their childhood residence along with subjective ratings of danger of that and their current location, which enabled us to compare their ratings of risk/danger with the federally reported crime statistics of each setting. Our results indicate that the early prevalence of registered sex offenders indeed influences an individual's risk perception in adulthood, and that these factors have a differential effect on males and females. Our findings provide support for the theory that early environmental factors signaling danger affect how individuals assess risk within their adult environment. © The Author(s) 2015.

  7. Soil nitrogen balance assessment and its application for sustainable agriculture and environment.

    PubMed

    Roy, Rabindra Nath; Misra, Ram Vimal

    2005-12-01

    Soil nitrogen balance assessment (SNBA) serves as an effective tool for estimating the magnitude of nitrogen loss/gain of the agro-eco systems and to appraise their sustainability. SNBA brings forth awareness of soil fertility problems, besides providing information relating to the resultant release of nitrogen into the environment consequent to agricultural practices. Quantitative information relating to nitrogen escape into the environment through such exercises can be gainfully utilized for identification of causative factors, enhancing fertilizer use efficiency and formulating programmes aimed at plugging N leakages. An overview of nitrogen balance approaches and methodologies is presented. A deeper understanding and insight into the agro-eco systems provided by the SNBA exercises can lay the basis for the formulation of effective agronomic interventions and policies aimed at promoting sustainable agriculture and a benign environment.

  8. Soil nitrogen balance assessment and its application for sustainable agriculture and environment.

    PubMed

    Roy, Rabindra Nath; Misra, Ram Vimal

    2005-09-01

    Soil nitrogen balance assessment (SNBA) serves as an effective tool for estimating the magnitude of nitrogen loss/gain of the agro-eco systems and to appraise their sustainability. SNBA brings forth awareness of soil fertility problems, besides providing information relating to the resultant release of nitrogen into the environment consequent to agricultural practices. Quantitative information relating to nitrogen escape into the environment through such exercises can be gainfully utilized for identification of causative factors, enhancing fertilizer use efficiency and formulating programmes aimed at plugging N leakages. An overview of nitrogen balance approaches and methodologies is presented. A deeper understanding and insight into the agro-eco systems provided by the SNBA exercises can lay the basis for the formulation of effective agronomic interventions and policies aimed at promoting sustainable agriculture and a benign environment.

  9. Feasibility of dose enhancement assessment: Preliminary results by means of Gd-infused polymer gel dosimeter and Monte Carlo study.

    PubMed

    Santibáñez, M; Guillen, Y; Chacón, D; Figueroa, R G; Valente, M

    2018-04-11

    This work reports the experimental development of an integral Gd-infused dosimeter suitable for Gd dose enhancement assessment along with Monte Carlo simulations applied to determine the dose enhancement by radioactive and X-ray sources of interest in conventional and electronic brachytherapy. In this context, capability to elaborate a stable and reliable Gd-infused dosimeter was the first goal aimed at direct and accurate measurements of dose enhancement due to Gd presence. Dose-response was characterized for standard and Gd-infused PAGAT polymer gel dosimeters by means of optical transmission/absorbance. The developed Gd-infused PAGAT dosimeters demonstrated to be stable presenting similar dose-response as standard PAGAT within a linear trend up to 13 Gy along with good post-irradiation readout stability verified at 24 and 48 h. Additionally, dose enhancement was evaluated for Gd-infused PAGAT dosimeters by means of Monte Carlo (PENELOPE) simulations considering scenarios for isotopic and X-ray generator sources. The obtained results demonstrated the feasibility of obtaining a maximum enhancement around of (14 ± 1)% for 192 Ir source and an average enhancement of (70 ± 13)% for 241 Am. However, dose enhancement up to (267 ± 18)% may be achieved if suitable filtering is added to the 241 Am source. On the other hand, optimized X-ray spectra may attain dose enhancements up to (253 ± 22) %, which constitutes a promising future alternative for replacing radioactive sources by implementing electronic brachytherapy achieving high dose levels. Copyright © 2018. Published by Elsevier Ltd.

  10. Development and reliability of an audit tool to assess the school physical activity environment across 12 countries

    PubMed Central

    Broyles, S T; Drazba, K T; Church, T S; Chaput, J-P; Fogelholm, M; Hu, G; Kuriyan, R; Kurpad, A; Lambert, E V; Maher, C; Maia, J; Matsudo, V; Olds, T; Onywera, V; Sarmiento, O L; Standage, M; Tremblay, M S; Tudor-Locke, C; Zhao, P; Katzmarzyk, P T

    2015-01-01

    Objectives: Schools are an important setting to enable and promote physical activity. Researchers have created a variety of tools to perform objective environmental assessments (or ‘audits') of other settings, such as neighborhoods and parks; yet, methods to assess the school physical activity environment are less common. The purpose of this study is to describe the approach used to objectively measure the school physical activity environment across 12 countries representing all inhabited continents, and to report on the reliability and feasibility of this methodology across these diverse settings. Methods: The International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) school audit tool (ISAT) data collection required an in-depth training (including field practice and certification) and was facilitated by various supporting materials. Certified data collectors used the ISAT to assess the environment of all schools enrolled in ISCOLE. Sites completed a reliability audit (simultaneous audits by two independent, certified data collectors) for a minimum of two schools or at least 5% of their school sample. Item-level agreement between data collectors was assessed with both the kappa statistic and percent agreement. Inter-rater reliability of school summary scores was measured using the intraclass correlation coefficient. Results: Across the 12 sites, 256 schools participated in ISCOLE. Reliability audits were conducted at 53 schools (20.7% of the sample). For the assessed environmental features, inter-rater reliability (kappa) ranged from 0.37 to 0.96; 18 items (42%) were assessed with almost perfect reliability (κ=0.80–0.96), and a further 24 items (56%) were assessed with substantial reliability (κ=0.61–0.79). Likewise, scores that summarized a school's support for physical activity were highly reliable, with the exception of scores assessing aesthetics and perceived suitability of the school grounds for sport, informal games and general

  11. The impact of low and intermediate-level radioactive waste on humans and the environment over the next one hundred thousand years.

    PubMed

    Kautsky, Ulrik; Saetre, Peter; Berglund, Sten; Jaeschke, Ben; Nordén, Sara; Brandefelt, Jenny; Keesmann, Sven; Näslund, Jens-Ove; Andersson, Eva

    2016-01-01

    In order to assess the potential radiological risk to humans and the environment from a geological repository for radioactive waste, a safety assessment must be performed. This implies that the release and transfer of radionuclides from the repository into the surface environment are calculated and that the effects in the biosphere are evaluated for an assessment period up to one hundred thousand years according to Swedish regulations. This paper discusses the challenges associated with the modelling of surface ecosystems over such long time scales, using the recently completed assessment for the extension of the existing repository for the low- and intermediate-level nuclear waste (called SFR) in Forsmark, Sweden as an applied example. In the assessment, natural variation and uncertainties in climate during the assessment period were captured by using a set of climate cases, primarily reflecting different expectations on the effects of global warming. Development of the landscape at the site, due to post-glacial isostatic rebound, was modelled, and areas where modelling indicated that radionuclides could discharge into the biosphere were identified. Transfers of surface water and groundwater were described with spatially distributed hydrological models. The projected release of radionuclides from the bedrock was then fed into a biosphere radionuclide transport model, simulating the transport and fate of radionuclides within and between ecosystems in the landscape. Annual doses for human inhabitants were calculated by combining activity concentrations in environmental media (soil, water, air and plants) with assumptions on habits and land-use of future human inhabitants. Similarly, dose rates to representative organisms of non-human biota were calculated from activity concentrations in relevant habitats, following the ERICA methodology. In the main scenario, the calculated risk for humans did not exceed the risk criteria or the screening dose rate for non

  12. Assessing patient dose in interventional fluoroscopy using patient-dependent hybrid phantoms

    NASA Astrophysics Data System (ADS)

    Johnson, Perry Barnett

    Interventional fluoroscopy uses ionizing radiation to guide small instruments through blood vessels or other body pathways to sites of clinical interest. The technique represents a tremendous advantage over invasive surgical procedures, as it requires only a small incision, thus reducing the risk of infection and providing for shorter recovery times. The growing use and increasing complexity of interventional procedures, however, has resulted in public health concerns regarding radiation exposures, particularly with respect to localized skin dose. Tracking and documenting patient-specific skin and internal organ dose has been specifically identified for interventional fluoroscopy where extended irradiation times, multiple projections, and repeat procedures can lead to some of the largest doses encountered in radiology. Furthermore, inprocedure knowledge of localized skin doses can be of significant clinical importance to managing patient risk and in training radiology residents. In this dissertation, a framework is presented for monitoring the radiation dose delivered to patients undergoing interventional procedures. The framework is built around two key points, developing better anthropomorphic models, and designing clinically relevant software systems for dose estimation. To begin, a library of 50 hybrid patient-dependent computational phantoms was developed based on the UF hybrid male and female reference phantoms. These phantoms represent a different type of anthropomorphic model whereby anthropometric parameters from an individual patient are used during phantom selection. The patient-dependent library was first validated and then used in two patient-phantom matching studies focused on cumulative organ and local skin dose. In terms of organ dose, patient-phantom matching was shown most beneficial for estimating the dose to large patients where error associated with soft tissue attenuation differences could be minimized. For small patients, inherent difference

  13. Assessing Impact of High-Dose Pitavastatin on Carotid Artery Elasticity with Speckle-Tracking Strain Imaging.

    PubMed

    Kim, Chee Hae; Wang, Shuang; Park, Jun-Bean; Jung, Keun-Hwa; Yoon, Yeonyee E; Lee, Seung-Pyo; Kim, Hyung-Kwan; Kim, Yong-Jin; Cho, Goo-Yeong; Sohn, Dae-Won

    2018-03-07

    Speckle-tracking imaging has been introduced for the precise assessment of vessel mechanics. However, there are no data on the role of this imaging tool in assessing the changes in vasculature with statin therapy, which is known to enhance vascular elasticity. This study was a prospective study including 48 statin-naïve patients (age, 58.2±8.4 years; 29.2% male) with hypercholesterolemia. Circumferential carotid artery strain (CAS) and stiffness index (β 2 ) were measured using speckle-tracking imaging before and after 3 months of high-dose pitavastatin treatment (4 mg daily). For the comparison, we measured conventional carotid elasticity parameters and intima-media thickness using B-mode ultrasound at the same time points. Compared with baseline, there was significant improvement in circumferential CAS (2.98%±1.18% to 3.40%±1.43%, p=0.008) and β 2 (0.19±0.07 to 0.17±0.08, p=0.047) after statin therapy. Contrariwise, there were no significant changes in all conventional carotid elasticity metrics and intima-media thickness. When stratifying patients into two subgroups by 10 year atherosclerotic cardiovascular disease (ASCVD) risk, speckle-tracking-derived circumferential CAS and β 2 improved significantly only in patients with ASCVD risk ≥ 7.5%. Short-term treatment with high-dose pitavastatin improved carotid artery elasticity measured by speckle-tracking method, but not conventional parameters by B-mode ultrasound. Speckle-tracking-based measurements may allow the early noninvasive assessment of statin effects on vascular function in hypercholesterolemic patients.

  14. Multi-component assessment of chronic obstructive pulmonary disease: an evaluation of the ADO and DOSE indices and the global obstructive lung disease categories in international primary care data sets

    PubMed Central

    Jones, Rupert C; Price, David; Chavannes, Niels H; Lee, Amanda J; Hyland, Michael E; Ställberg, Björn; Lisspers, Karin; Sundh, Josefin; van der Molen, Thys; Tsiligianni, Ioanna

    2016-01-01

    Suitable tools for assessing the severity of chronic obstructive pulmonary disease (COPD) include multi-component indices and the global initiative for chronic obstructive lung disease (GOLD) categories. The aim of this study was to evaluate the dyspnoea, obstruction, smoking, exacerbation (DOSE) and the age, dyspnoea, obstruction (ADO) indices and GOLD categories as measures of current health status and future outcomes in COPD patients. This was an observational cohort study comprising 5,114 primary care COPD patients across three databases from UK, Sweden and Holland. The associations of DOSE and ADO indices with (i) health status using the Clinical COPD Questionnaire (CCQ) and St George’s Respiratory Questionnaire (SGRQ) and COPD Assessment test (CAT) and with (ii) current and future exacerbations, admissions and mortality were assessed in GOLD categories and DOSE and ADO indices. DOSE and ADO indices were significant predictors of future exacerbations: incident rate ratio was 1.52 (95% confidence intervals 1.46–1.57) for DOSE, 1.16 (1.12–1.20) for ADO index and 1.50 (1.33–1.68) and 1.23 (1.10–1.39), respectively, for hospitalisations. Negative binomial regression showed that the DOSE index was a better predictor of future admissions than were its component items. The hazard ratios for mortality were generally higher for ADO index groups than for DOSE index groups. The GOLD categories produced widely differing assessments for future exacerbation risk or for hospitalisation depending on the methods used to calculate them. None of the assessment systems were excellent at predicting future risk in COPD; the DOSE index appears better than the ADO index for predicting many outcomes, but not mortality. The GOLD categories predict future risk inconsistently. The DOSE index and the GOLD categories using exacerbation frequency may be used to identify those at high risk for exacerbations and admissions. PMID:27053297

  15. Multi-component assessment of chronic obstructive pulmonary disease: an evaluation of the ADO and DOSE indices and the global obstructive lung disease categories in international primary care data sets.

    PubMed

    Jones, Rupert C; Price, David; Chavannes, Niels H; Lee, Amanda J; Hyland, Michael E; Ställberg, Björn; Lisspers, Karin; Sundh, Josefin; van der Molen, Thys; Tsiligianni, Ioanna

    2016-04-07

    Suitable tools for assessing the severity of chronic obstructive pulmonary disease (COPD) include multi-component indices and the global initiative for chronic obstructive lung disease (GOLD) categories. The aim of this study was to evaluate the dyspnoea, obstruction, smoking, exacerbation (DOSE) and the age, dyspnoea, obstruction (ADO) indices and GOLD categories as measures of current health status and future outcomes in COPD patients. This was an observational cohort study comprising 5,114 primary care COPD patients across three databases from UK, Sweden and Holland. The associations of DOSE and ADO indices with (i) health status using the Clinical COPD Questionnaire (CCQ) and St George's Respiratory Questionnaire (SGRQ) and COPD Assessment test (CAT) and with (ii) current and future exacerbations, admissions and mortality were assessed in GOLD categories and DOSE and ADO indices. DOSE and ADO indices were significant predictors of future exacerbations: incident rate ratio was 1.52 (95% confidence intervals 1.46-1.57) for DOSE, 1.16 (1.12-1.20) for ADO index and 1.50 (1.33-1.68) and 1.23 (1.10-1.39), respectively, for hospitalisations. Negative binomial regression showed that the DOSE index was a better predictor of future admissions than were its component items. The hazard ratios for mortality were generally higher for ADO index groups than for DOSE index groups. The GOLD categories produced widely differing assessments for future exacerbation risk or for hospitalisation depending on the methods used to calculate them. None of the assessment systems were excellent at predicting future risk in COPD; the DOSE index appears better than the ADO index for predicting many outcomes, but not mortality. The GOLD categories predict future risk inconsistently. The DOSE index and the GOLD categories using exacerbation frequency may be used to identify those at high risk for exacerbations and admissions.

  16. Assessment of a University Campus Food Environment, California, 2015.

    PubMed

    Tseng, Marilyn; DeGreef, Kelsey; Fishler, Madison; Gipson, Rachel; Koyano, Kelly; Neill, Dawn B

    2016-02-04

    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. 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. 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. 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.

  17. The Evolution of the Sustainability Assessment Tool SBToolPT: From Buildings to the Built Environment

    PubMed Central

    Bragança, Luís

    2014-01-01

    This paper analyses the current trends in sustainability assessment. After about 15 years from the launch of sustainability assessment tools, focused on buildings evaluation, the paradigm of sustainability assessment tools is changing from the building scale to the built environment scale. Currently European cities and cities around the world are concerned with sustainable development, as well as its evolution. Cities seek a way to adapt to contemporary changes, in order to meet the required needs and ensure population's well-being. Considering this, the new generations of sustainability assessment tools are being developed to be used to guide and help cities and urban areas to become more sustainable. Following the trend of the most important sustainability assessment tools, the sustainability assessment tool SBToolPT is also developing its version for assessing the sustainability of the built environment, namely, the urban planning projects and the urban regeneration projects, to be developed in Portugal, the SBToolPT-UP. The application of the methodology to three case studies will demonstrate its feasibility; at the same time this will identify the best practices which will serve as reference for new projects, thereby assisting the development of the tool. PMID:24592171

  18. The evolution of the sustainability assessment tool SBToolPT: from buildings to the built environment.

    PubMed

    Castanheira, Guilherme; Bragança, Luís

    2014-01-01

    This paper analyses the current trends in sustainability assessment. After about 15 years from the launch of sustainability assessment tools, focused on buildings evaluation, the paradigm of sustainability assessment tools is changing from the building scale to the built environment scale. Currently European cities and cities around the world are concerned with sustainable development, as well as its evolution. Cities seek a way to adapt to contemporary changes, in order to meet the required needs and ensure population's well-being. Considering this, the new generations of sustainability assessment tools are being developed to be used to guide and help cities and urban areas to become more sustainable. Following the trend of the most important sustainability assessment tools, the sustainability assessment tool SBTool(PT) is also developing its version for assessing the sustainability of the built environment, namely, the urban planning projects and the urban regeneration projects, to be developed in Portugal, the SBTool(PT)-UP. The application of the methodology to three case studies will demonstrate its feasibility; at the same time this will identify the best practices which will serve as reference for new projects, thereby assisting the development of the tool.

  19. Microbial Risk Assessment

    NASA Technical Reports Server (NTRS)

    Ott, C. M.; Mena, K. D.; Nickerson, C.A.; Pierson, D. L.

    2009-01-01

    Historically, microbiological spaceflight requirements have been established in a subjective manner based upon expert opinion of both environmental and clinical monitoring results and the incidence of disease. The limited amount of data, especially from long-duration missions, has created very conservative requirements based primarily on the concentration of microorganisms. Periodic reevaluations of new data from later missions have allowed some relaxation of these stringent requirements. However, the requirements remain very conservative and subjective in nature, and the risk of crew illness due to infectious microorganisms is not well defined. The use of modeling techniques for microbial risk has been applied in the food and potable water industries and has exceptional potential for spaceflight applications. From a productivity standpoint, this type of modeling can (1) decrease unnecessary costs and resource usage and (2) prevent inadequate or inappropriate data for health assessment. In addition, a quantitative model has several advantages for risk management and communication. By identifying the variable components of the model and the knowledge associated with each component, this type of modeling can: (1) Systematically identify and close knowledge gaps, (2) Systematically identify acceptable and unacceptable risks, (3) Improve communication with stakeholders as to the reasons for resource use, and (4) Facilitate external scientific approval of the NASA requirements. The modeling of microbial risk involves the evaluation of several key factors including hazard identification, crew exposure assessment, dose-response assessment, and risk characterization. Many of these factors are similar to conditions found on Earth; however, the spaceflight environment is very specialized as the inhabitants live in a small, semi-closed environment that is often dependent on regenerative life support systems. To further complicate modeling efforts, microbial dose

  20. Depth Dose Distribution Study within a Phantom Torso after Irradiation with a Simulated Solar Particle Event at NSRL

    NASA Technical Reports Server (NTRS)

    Berger, Thomas; Matthiae, Daniel; Koerner, Christine; George, Kerry; Rhone, Jordan; Cucinotta, Francis; Reitz, Guenther

    2010-01-01

    The adequate knowledge of the radiation environment and the doses incurred during a space mission is essential for estimating an astronaut's health risk. The space radiation environment is complex and variable, and exposures inside the spacecraft and the astronaut's body are compounded by the interactions of the primary particles with the atoms of the structural materials and with the body itself Astronauts' radiation exposures are measured by means of personal dosimetry, but there remains substantial uncertainty associated with the computational extrapolation of skin dose to organ dose, which can lead to over- or underestimation of the health risk. Comparisons of models to data showed that the astronaut's Effective dose (E) can be predicted to within about a +10% accuracy using space radiation transport models for galactic cosmic rays (GCR) and trapped radiation behind shielding. However for solar particle event (SPE) with steep energy spectra and for extra-vehicular activities on the surface of the moon where only tissue shielding is present, transport models predict that there are large differences in model assumptions in projecting organ doses. Therefore experimental verification of SPE induced organ doses may be crucial for the design of lunar missions. In the research experiment "Depth dose distribution study within a phantom torso" at the NASA Space Radiation Laboratory (NSRL) at BNL, Brookhaven, USA the large 1972 SPE spectrum was simulated using seven different proton energies from 50 up to 450 MeV. A phantom torso constructed of natural bones and realistic distributions of human tissue equivalent materials, which is comparable to the torso of the MATROSHKA phantom currently on the ISS, was equipped with a comprehensive set of thermoluminescence detectors and human cells. The detectors are applied to assess the depth dose distribution and radiation transport codes (e.g. GEANT4) are used to assess the radiation field and interactions of the radiation field

  1. The use of ESR spectroscopy for the identification and dose assessment of irradiated pink shrimp (Parapenaeus longirostris) from Turkey

    NASA Astrophysics Data System (ADS)

    Aydaş, Canan; Tepe Çam, Semra; Engin, Birol; Aydın, Talat; Polat, Mustafa

    2013-03-01

    Turkish pink shrimp (Parapenaeus longirostris) samples were studied by electron spin resonance (ESR) spectroscopy for identification and dose assessment purposes. In this work, the calcified shells of shrimps were used as a sample material. Before irradiation, all shrimp shell samples exhibit one weak ESR singlet with a g-factor of 2.0047. After irradiation, all samples exhibit two asymmetric ESR signal components centered at g-values of 2.0013 and 1.9959. The dose-response curves of the samples exposed to gamma radiations were found to be described well by a single saturation exponential function. Variation of ESR signal intensity of irradiated samples at room and-20 °C temperatures with time in a long-term showed that free radicals responsible from the ESR spectrum of shrimp shells were not stable but still detectable after 87 days. Also, the kinetic behavior of signal at g=2.0013 was studied and the additive dose method was used to evaluate the dose in the product.

  2. Allometric methodology for the assessment of radon exposures to terrestrial wildlife.

    PubMed

    Vives i Batlle, J; Copplestone, D; Jones, S R

    2012-06-15

    A practical approach to calculate (222)Rn daughter dose rates to terrestrial wildlife is presented. The method scales allometrically the relevant parameters for respiration in different species of wildlife, allowing inter-species calculation of the dose per unit radon concentration in air as simple base-and-exponent power functions of the mass. For plants, passive gas exchange through the leaf surface is assumed, also leading to specific power relationships with mass. The model generates conservative predictions in which the main contributor to the dose rate of target tissues of the respiratory system is from α radiation arising from (222)Rn daughters. Tabulated (222)Rn DPURn values are given for 69 species used by the England & Wales Environment Agency for habitats assessments. The approach is then applied to assess the authorised discharges of (222)Rn from sites in England, demonstrating that, from a whole-body dose perspective, the biota considered are protected from effects at the population level. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. 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.

  4. Space Environment Effects on Materials : An Overview

    NASA Technical Reports Server (NTRS)

    Garrett, Henry B.

    2006-01-01

    A general overview on the space environment and its effects on materials is presented. The topics include: 1) Impact of Space Effects on Spacecraft Costs; 2) Space Environment Effects on Spacecraft by Source; 3) Primary Source of Space Effects: The Sun; 4) The Earth's Environment; 5) Trapped Radiation Belts; 6) Aurora Are Everywhere; 7) Spacecraft Interactions; 8) Atmospheric Effects; 9) Contaminant Effects on Materials; 10) Meteoroid/Debris Effects on Materials; 11) Spacecraft Surface Charging; 12) Surface Discharge Effects; 13) Internal Electrostatic Discharge--Satellite Killer; 14) Plasma Interactions DS-1 Ion Engines; 15) Radiation Effects on Spacecraft Systems and Materials; 16) Total Ionizing Dose Effects Total Ionizing Dose Effects; 17) Man-Made Sources of Space Effects Man-Made Sources of Space Effects; and 18) Space Environments Versus Interactions.

  5. Space radiation absorbed dose distribution in a human phantom

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Atwell, W.; Badavi, F. F.; Yang, T. C.; Cleghorn, T. F.

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  6. New Approach to Total Dose Specification for Spacecraft Electronics

    NASA Technical Reports Server (NTRS)

    Xapsos, Michael

    2017-01-01

    Variability of the space radiation environment is investigated with regard to total dose specification for spacecraft electronics. It is shown to have a significant impact. A new approach is developed for total dose requirements that replaces the radiation design margin concept with failure probability during a mission.

  7. 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.

  8. Analysis of Transcriptomic Dose Response Data in the ...

    EPA Pesticide Factsheets

    Slide presentation at the HESI-HEALTH Canada-McGill Workshop on Transcriptomic Dose Response Data in the Context of Chemical Risk Assessment Slide presentation at the HESI-HEALTH Canada-McGill Workshop on Transcriptomic Dose Response Data in the Context of Chemical Risk Assessment

  9. Dual-energy computed tomography of the head: a phantom study assessing axial dose distribution, eye lens dose, and image noise level

    NASA Astrophysics Data System (ADS)

    Matsubara, Kosuke; Kawashima, Hiroki; Hamaguchi, Takashi; Takata, Tadanori; Kobayashi, Masanao; Ichikawa, Katsuhiro; Koshida, Kichiro

    2016-03-01

    The aim of this study was to propose a calibration method for small dosimeters to measure absorbed doses during dual- source dual-energy computed tomography (DECT) and to compare the axial dose distribution, eye lens dose, and image noise level between DE and standard, single-energy (SE) head CT angiography. Three DE (100/Sn140 kVp 80/Sn140 kVp, and 140/80 kVp) and one SE (120 kVp) acquisitions were performed using a second-generation dual-source CT device and a female head phantom, with an equivalent volumetric CT dose index. The axial absorbed dose distribution at the orbital level and the absorbed doses for the eye lens were measured using radiophotoluminescent glass dosimeters. CT attenuation numbers were obtained in the DE composite images and the SE images of the phantom at the orbital level. The doses absorbed at the orbital level and in the eye lens were lower and standard deviations for the CT attenuation numbers were slightly higher in the DE acquisitions than those in the SE acquisition. The anterior surface dose was especially higher in the SE acquisition than that in the DE acquisitions. Thus, DE head CT angiography can be performed with a radiation dose lower than that required for a standard SE head CT angiography, with a slight increase in the image noise level. The 100/Sn140 kVp acquisition revealed the most balanced axial dose distribution. In addition, our proposed method was effective for calibrating small dosimeters to measure absorbed doses in DECT.

  10. Comparative Assessment of a Single Dose and a 2-dose Vaccination Series of a Quadrivalent Meningococcal CRM-conjugate Vaccine (MenACWY-CRM) in Children 2-10 Years of Age.

    PubMed

    Johnston, William; Essink, Brandon; Kirstein, Judith; Forleo-Neto, Eduardo; Percell, Sandra; Han, Linda; Keshavan, Pavitra; Smolenov, Igor

    2016-01-01

    We compared the immunogenicity, safety and 1-year antibody persistence of a single-dose and a 2-dose series of a licensed meningococcal ACWY-CRM conjugate vaccine (MenACWY-CRM) in 2- to 10-year-old children. In this phase III, multicenter, observer-blind study, children aged 2-5 years (n = 359) and 6-10 years (n = 356) were randomized 1:1 to receive 2 doses of MenACWY-CRM (ACWY2) or 1 dose of placebo followed by 1 dose of MenACWY-CRM (ACWY1), 2 months apart. Immunogenicity was measured using serum bactericidal activity with human complement (hSBA). Primary outcomes were to assess the immunologic noninferiority and superiority of ACWY2 versus ACWY1. One-month after the second dose, the hSBA seroresponse in ACWY2 was noninferior to ACWY1 for all 4 serogroups, in both age cohorts, and was superior for serogroups C and Y in the 2- to 5-year-old age cohort and for serogroup Y in the 6- to 10-year-old age cohort. Overall, 90%-99% of subjects in ACWY2 and 65%-96% in ACWY1 had hSBA titers ≥ 8; geometric mean titers were 1.8- to 6.4-fold higher in ACWY2 than ACWY1 across serogroups. At 1 year postvaccination, geometric mean titers declined, and the differences between ACWY2 and ACWY1 remained significant for serogroups A and C in the 2- to 5-year-old age cohort and for serogroups C and Y in the 6- to 10-year-old age cohort. The safety profile of MenACWY-CRM was similar in both groups. The single dose and 2-dose MenACWY-CRM series were immunogenic and well tolerated. Although antibody responses were greater after 2 doses, especially in the 2- to 5-year-old age cohort, this difference was less pronounced at 1 year postvaccination.

  11. Human Health Risk Assessment (HHRA) for environmental development and transfer of antibiotic resistance.

    PubMed

    Ashbolt, Nicholas J; Amézquita, Alejandro; Backhaus, Thomas; Borriello, Peter; Brandt, Kristian K; Collignon, Peter; Coors, Anja; Finley, Rita; Gaze, William H; Heberer, Thomas; Lawrence, John R; Larsson, D G Joakim; McEwen, Scott A; Ryan, James J; Schönfeld, Jens; Silley, Peter; Snape, Jason R; Van den Eede, Christel; Topp, Edward

    2013-09-01

    Only recently has the environment been clearly implicated in the risk of antibiotic resistance to clinical outcome, but to date there have been few documented approaches to formally assess these risks. We examined possible approaches and sought to identify research needs to enable human health risk assessments (HHRA) that focus on the role of the environment in the failure of antibiotic treatment caused by antibiotic-resistant pathogens. The authors participated in a workshop held 4-8 March 2012 in Québec, Canada, to define the scope and objectives of an environmental assessment of antibiotic-resistance risks to human health. We focused on key elements of environmental-resistance-development "hot spots," exposure assessment (unrelated to food), and dose response to characterize risks that may improve antibiotic-resistance management options. Various novel aspects to traditional risk assessments were identified to enable an assessment of environmental antibiotic resistance. These include a) accounting for an added selective pressure on the environmental resistome that, over time, allows for development of antibiotic-resistant bacteria (ARB); b) identifying and describing rates of horizontal gene transfer (HGT) in the relevant environmental "hot spot" compartments; and c) modifying traditional dose-response approaches to address doses of ARB for various health outcomes and pathways. We propose that environmental aspects of antibiotic-resistance development be included in the processes of any HHRA addressing ARB. Because of limited available data, a multicriteria decision analysis approach would be a useful way to undertake an HHRA of environmental antibiotic resistance that informs risk managers.

  12. The Fukushima releases: an inverse modelling approach to assess the source term by using gamma dose rate observations

    NASA Astrophysics Data System (ADS)

    Saunier, Olivier; Mathieu, Anne; Didier, Damien; Tombette, Marilyne; Quélo, Denis; Winiarek, Victor; Bocquet, Marc

    2013-04-01

    The Chernobyl nuclear accident and more recently the Fukushima accident highlighted that the largest source of error on consequences assessment is the source term estimation including the time evolution of the release rate and its distribution between radioisotopes. Inverse modelling methods have proved to be efficient to assess the source term due to accidental situation (Gudiksen, 1989, Krysta and Bocquet, 2007, Stohl et al 2011, Winiarek et al 2012). These methods combine environmental measurements and atmospheric dispersion models. They have been recently applied to the Fukushima accident. Most existing approaches are designed to use air sampling measurements (Winiarek et al, 2012) and some of them use also deposition measurements (Stohl et al, 2012, Winiarek et al, 2013). During the Fukushima accident, such measurements are far less numerous and not as well distributed within Japan than the dose rate measurements. To efficiently document the evolution of the contamination, gamma dose rate measurements were numerous, well distributed within Japan and they offered a high temporal frequency. However, dose rate data are not as easy to use as air sampling measurements and until now they were not used in inverse modelling approach. Indeed, dose rate data results from all the gamma emitters present in the ground and in the atmosphere in the vicinity of the receptor. They do not allow one to determine the isotopic composition or to distinguish the plume contribution from wet deposition. The presented approach proposes a way to use dose rate measurement in inverse modeling approach without the need of a-priori information on emissions. The method proved to be efficient and reliable when applied on the Fukushima accident. The emissions for the 8 main isotopes Xe-133, Cs-134, Cs-136, Cs-137, Ba-137m, I-131, I-132 and Te-132 have been assessed. The Daiichi power plant events (such as ventings, explosions…) known to have caused atmospheric releases are well identified in

  13. Assessment of radiation doses from residential smoke detectors that contain americium-241

    NASA Astrophysics Data System (ADS)

    Odonnell, F. R.; Etnier, E. L.; Holton, G. A.; Travis, C. C.

    1981-10-01

    External dose equivalents and internal dose commitments were estimated for individuals and populations from annual distribution, use, and disposal of 10 million ionization chamber smoke detectors that contain 110 kBq americium-241 each. Under exposure scenarios developed for normal distribution, use, and disposal using the best available information, annual external dose equivalents to average individuals were estimated to range from 4 fSv to 20 nSv for total body and from 7 fSv to 40 nSv for bone. Internal dose commitments to individuals under post disposal scenarios were estimated to range from 0.006 to 80 micro-Sv (0.0006 to 8 mrem) to total body and from 0.06 to 800 micro-Sv to bone. The total collective dose (the sum of external dose equivalents and 50-year internal dose commitments) for all individuals involved with distribution, use, or disposal of 10 million smoke detectors was estimated to be about 0.38 person-Sv (38 person-rem) to total body and 00 ft squared.

  14. An Assessment of Normalized Difference Skin Index Robustness in Aquatic Environments

    DTIC Science & Technology

    2014-03-27

    Index NDSI Normalized Difference Skin Index NDVI Normalized Difference Vegetation Index NIR Near-Infrared SAR Search and Rescue SERG Sensors... Vegetation and water-bearing objects with high scatter tend to have NDSI values similar to human skin , potentially causing false positives in certain...AN ASSESSMENT OF NORMALIZED DIFFERENCE SKIN INDEX ROBUSTNESS IN AQUATIC ENVIRONMENTS THESIS Alice W. Chan, First Lieutenant, USAF AFIT-ENG-14-M-17

  15. Radiation and Plasma Environments for Lunar Missions

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Edwards, David L.; Altstatt, Richard L.; Diekmann, Anne M.; Blackwell, William C., Jr.; Harine, Katherine J.

    2006-01-01

    Space system design for lunar orbit and extended operations on the lunar surface requires analysis of potential system vulnerabilities to plasma and radiation environments to minimize anomalies and assure that environmental failures do not occur during the mission. Individual environments include the trapped particles in Earth s radiation belts, solar energetic particles and galactic cosmic rays, plasma environments encountered in transit to the moon and on the lunar surface (solar wind, terrestrial magnetosheath and magnetotail, and lunar photoelectrons), and solar ultraviolet and extreme ultraviolet photons. These are the plasma and radiation environments which contribute to a variety of effects on space systems including total ionizing dose and dose rate effects in electronics, degradation of materials in the space environment, and charging of spacecraft and lunar dust. This paper provides a survey of the relevant charged particle and photon environments of importance to lunar mission design ranging from the lowest (approx.few 10 s eV) photoelectron energies to the highest (approx.GeV) cosmic ray energies.

  16. Myocardial viability assessment after acute myocardial infarction: low-dose dobutamine echocardiography versus rest-redistribution thallium-201 SPECT.

    PubMed

    Castini, D; Bestetti, A; Garbin, M; Di Leo, C; Bigi, R; Sponzilli, C; Concardi, G; Gioventù, M; Tarolo, G L; Lombardi, F; Fiorentini, C

    1999-09-01

    The presence of tissue viability is of great importance in the prognostic work-up of patients recovering from acute myocardial infarction. However, uncertainty still exists concerning the optimal tool for its assessment. The present study was undertaken in order to compare low-dose dobutamine echocardiography and rest-redistribution thallium SPECT for predicting late improvement of regional left ventricular function after acute myocardial infarction. Fifteen patients undergoing coronary angiography, low-dose dobutamine echocardiography and rest-redistribution thallium SPECT after thrombolyzed anterior acute myocardial infarction were studied. A 3 month follow-up echocardiogram was performed in all patients and 9 underwent coronary revascularization. A significant (> or = 70%) residual stenosis of the infarct-related artery was present in 14 patients, whilst a total occlusion was observed in 1. At 3 month follow-up, 41% of the dyssynergic segments improved. The sensitivity, specificity and accuracy for late wall motion improvement was 61, 89 and 77% for low-dose dobutamine echocardiography and, respectively, 76, 45 and 58% for rest-redistribution thallium SPECT. Tissue viability was detected in 65 and 31% of dyssynergic segments by rest-redistribution thallium SPECT and low-dose dobutamine echocardiography, respectively (p < 0.001). The agreement between the two techniques was 48%. Low-dose dobutamine echocardiography is more accurate than rest-redistribution thallium SPECT for predicting 3 month wall motion improvement in patients with acute anterior myocardial infarction, mainly due to its significantly better specificity.

  17. Workshop on an Assessment of Gas-Side Fouling in Fossil Fuel Exhaust Environments

    NASA Technical Reports Server (NTRS)

    Marner, W. J. (Editor); Webb, R. L. (Editor)

    1982-01-01

    The state of the art of gas side fouling in fossil fuel exhaust environments was assessed. Heat recovery applications were emphasized. The deleterious effects of gas side fouling including increased energy consumption, increased material losses, and loss of production were identified.

  18. Medical Students' Perception of Their Educational Environment and Quality of Life: Is There a Positive Association?

    PubMed

    Enns, Sylvia Claassen; Perotta, Bruno; Paro, Helena B; Gannam, Silmar; Peleias, Munique; Mayer, Fernanda Brenneisen; Santos, Itamar Souza; Menezes, Marta; Senger, Maria Helena; Barelli, Cristiane; Silveira, Paulo S P; Martins, Milton A; Zen Tempski, Patricia

    2016-03-01

    To assess perceptions of educational environment of students from 22 Brazilian medical schools and to study the association between these perceptions and quality of life (QoL) measures. The authors performed a multicenter study (August 2011 to August 2012), examining students' views both of (1) educational environment using the Dundee Ready Education Environment Measure (DREEM) and (2) QoL using the World Health Organization Quality of Life Assessment, abbreviated version (WHOQOL-BREF). They also examined students' self-assessment of their overall QoL and medical-school-related QoL (MSQoL). The authors classified participants' perceptions into four quartiles according to DREEM total score, overall QoL, and MSQoL. Of 1,650 randomly selected students, 1,350 (81.8%) completed the study. The mean total DREEM score was 119.4 (standard deviation = 27.1). Higher total DREEM scores were associated with higher overall QoL and MSQoL scores (P < .001 for all comparisons) and younger ages (P < .001). Mean overall QoL scores were higher than MSQoL scores (mean difference, 1.35; 95% confidence interval [CI] 1.28-1.43; P < .001). Multinomial regression models showed significant dose-response patterns: Higher DREEM quartile scores were associated with better QoL. The psychological health domain of WHOQOL-BREF was most closely associated with DREEM scores (odds ratio 4.70; 95% CI = 3.80-5.81). The authors observed a positive association between QoL measures and DREEM scores. This association had a dose-response effect, independent of age, sex, and year of medical training, showing that educational environment appears to be an important moderator of medical student QoL.

  19. Diagnostic Doses of Insecticides for Adult Aedes aegypti to Assess Insecticide Resistance in Cuba.

    PubMed

    Rodríguez, María Magdalena; Crespo, Ariel; Hurtado, Daymi; Fuentes, Ilario; Rey, Jorge; Bisset, Juan Andrés

    2017-06-01

    The objective of this study was to determine diagnostic doses (DDs) of 5 insecticides for the Rockefeller susceptible strain of Aedes aegypti , using the Centers for Disease Control and Prevention (CDC) bottle bioassay as a tool for monitoring insecticide resistance in the Cuban vector control program. The 30-min DD values determined in this study were 13.5 μg/ml, 6.5 μg/ml, 6 μg/ml, 90.0 μg/ml, and 15.0 μg/ml for cypermethrin, deltamethrin, lambda-cyhalothrin, chlorpyrifos, and propoxur, respectively. To compare the reliability of CDC bottle bioassay with the World Health Organization susceptible test, 3 insecticide-resistant strains were evaluated for deltamethrin and lambda-cyhalothrin. Results showed that the bottles can be used effectively from 21 to 25 days after treatment and reused up to 4 times, depending on the storage time. The CDC bottle bioassay is an effective tool to assess insecticide resistance in field populations of Ae. aegypti in Cuba and can be incorporated into vector management programs using the diagnostic doses determined in this study.

  20. Participatory Formative Assessment in an Environment of High-Stakes Testing: An Autoethnography

    ERIC Educational Resources Information Center

    Johnson, Karin Pogna

    2011-01-01

    The purpose of this study was to describe my experiences as a campus principal in facilitating the use of participatory formative assessment (PFA) in an environment of accountability and high-stakes testing. The methodology I employed was autoethnography (Chang, 2008; Ellis, 2004; Reed-Danahay, 1997; Stinson, 2009). I kept journals over a period…

  1. Assessing changes in HIV-related legal and policy environments: Lessons learned from a multi-country evaluation.

    PubMed

    Ferguson, Laura; Nicholson, Alexandra; Henry, Ian; Saha, Amitrajit; Sellers, Tilly; Gruskin, Sofia

    2018-01-01

    There is growing recognition in the health community that the legal environment-including laws, policies, and related procedures-impacts vulnerability to HIV and access to HIV-related services both positively and negatively. Assessing changes in the legal environment and how these affect HIV-related outcomes, however, is challenging, and understanding of appropriate methodologies nascent. We conducted an evaluation of a UNDP project designed to strengthen legal environments to support the human rights of key populations, in particular LGBT populations, women and girls, affected by HIV in sub-Saharan Africa. We analyzed data on activities designed to improve legal environments through a systematic document review and 53 qualitative interviews. The project made substantial strides towards legal change in many places, and examples provide broader lessons for work in this area. Two core pillars appear fundamental: a government-led participatory assessment of the legal environment, and building the capacity of those impacted by and engaged in this work. Systematic attention to human rights is vital: it can help open new spaces for dialogue among diverse stakeholders, foster new collaborations, and ensure local ownership, nuanced understanding of the political landscape, attention to marginalized populations, and accountability for (in)action. Entry points for effecting legal change go beyond "HIV laws" to also include other laws, national policies and strategies. Conducting legal environment assessments, multi-stakeholder dialogues, action planning and related activities, alongside capacity building, can contribute to changes in knowledge and attitudes directly relevant to reforming laws that are found to be harmful. Shorter-term goals along the causal pathway to legal change (e.g. changes in policy) can constitute interim markers of success, and recognition of these can maintain momentum. Increasing understanding of progress towards changes in the legal environment

  2. Avoiding Pitfalls in the Use of the Benchmark Dose Approach to Chemical Risk Assessments; Some Illustrative Case Studies (Presentation)

    EPA Science Inventory

    The USEPA's benchmark dose software (BMDS) version 1.2 has been available over the Internet since April, 2000 (epa.gov/ncea/bmds.htm), and has already been used in risk assessments of some significant environmental pollutants (e.g., diesel exhaust, dichloropropene, hexachlorocycl...

  3. Occupational radiation doses during interventional procedures

    NASA Astrophysics Data System (ADS)

    Nuraeni, N.; Hiswara, E.; Kartikasari, D.; Waris, A.; Haryanto, F.

    2016-03-01

    Digital subtraction angiography (DSA) is a type of fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. The use of DSA procedures has been increased quite significantly in the Radiology departments in various cities in Indonesia. Various reports showed that both patients and medical staff received a noticeable radiation dose during the course of this procedure. A study had been carried out to measure these doses among interventionalist, nurse and radiographer. The results show that the interventionalist and the nurse, who stood quite close to the X-ray beams compared with the radiographer, received radiation higher than the others. The results also showed that the radiation dose received by medical staff were var depending upon the duration and their position against the X-ray beams. Compared tothe dose limits, however, the radiation dose received by all these three medical staff were still lower than the limits.

  4. Kodak EDR2 film for patient skin dose assessment in cardiac catheterization procedures.

    PubMed

    Morrell, R E; Rogers, A T

    2006-07-01

    Patient skin doses were measured using Kodak EDR2 film for 20 coronary angiography (CA) and 32 percutaneous transluminal coronary angioplasty (PTCA) procedures. For CA, all skin doses were well below 1 Gy. However, 23% of PTCA patients received skin doses of 1 Gy or more. Dose-area product (DAP) was also recorded and was found to be an inadequate indicator of maximum skin dose. Practical compliance with ICRP recommendations requires a robust method for skin dosimetry that is more accurate than DAP and is applicable over a wider dose range than EDR2 film.

  5. Assessment of radiation doses from residential smoke detectors that contain americium-241

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    O'Donnell, F.R.; Etnier, E.L.; Holton, G.A.

    1981-10-01

    External dose equivalents and internal dose commitments were estimated for individuals and populations from annual distribution, use, and disposal of 10 million ionization chamber smoke detectors that contain 110 kBq (3 ..mu..Ci) americium-241 each. Under exposure scenarios developed for normal distribution, use, and disposal using the best available information, annual external dose equivalents to average individuals were estimated to range from 4 fSv (0.4 prem) to 20 nSv (2 ..mu..rem) for total body and from 7 fSv to 40 nSv for bone. Internal dose commitments to individuals under post disposal scenarios were estimated to range from 0.006 to 80 ..mu..Svmore » (0.0006 to 8 mrem) to total body and from 0.06 to 800 ..mu..Sv to bone. The total collective dose (the sum of external dose equivalents and 50-year internal dose commitments) for all individuals involved with distribution, use, or disposal of 10 million smoke detectors was estimated to be about 0.38 person-Sv (38 person-rem) to total body and 00 ft/sup 2/).« less

  6. 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

  7. Assessment of simulated high-dose partial-body irradiation by PCC-R assay.

    PubMed

    Romero, Ivonne; García, Omar; Lamadrid, Ana I; Gregoire, Eric; González, Jorge E; Morales, Wilfredo; Martin, Cécile; Barquinero, Joan-Francesc; Voisin, Philippe

    2013-09-01

    The estimation of the dose and the irradiated fraction of the body is important information in the primary medical response in case of a radiological accident. The PCC-R assay has been developed for high-dose estimations, but little attention has been given to its applicability for partial-body irradiations. In the present work we estimated the doses and the percentage of the irradiated fraction in simulated partial-body radiation exposures at high doses using the PCC-R assay. Peripheral whole blood of three healthy donors was exposed to doses from 0-20 Gy, with ⁶⁰Co gamma radiation. To simulate partial body irradiations, irradiated and non-irradiated blood was mixed to obtain proportions of irradiated blood from 10-90%. Lymphocyte cultures were treated with Colcemid and Calyculin-A before harvest. Conventional and triage scores were performed for each dose, proportion of irradiated blood and donor. The Papworth's u test was used to evaluate the PCC-R distribution per cell. A dose-response relationship was fitted according to the maximum likelihood method using the frequencies of PCC-R obtained from 100% irradiated blood. The dose to the partially irradiated blood was estimated using the Contaminated Poisson method. A new D₀ value of 10.9 Gy was calculated and used to estimate the initial fraction of irradiated cells. The results presented here indicate that by PCC-R it is possible to distinguish between simulated partial- and whole-body irradiations by the u-test, and to accurately estimate the dose from 10-20 Gy, and the initial fraction of irradiated cells in the interval from 10-90%.

  8. APPLICATION AND USE OF DOSE ESTIMATING EXPOSURE MODEL (DEEM) FOR ROUTE TO ROUTE DOSE COMPARISONS AFTER EXPOSURE TO TRICHLOROETHYLENE (TCE)

    EPA Science Inventory

    Route-to-route extrapolations are a crucial step in many risk assessments. Often the doses which result In toxicological end points in one route must be compared with doses resulting from typical environmental exposures by another route. In this case we used EPA's Dose Estimati...

  9. Assessment of RF exposures from emerging wireless communication technologies in different environments.

    PubMed

    Joseph, Wout; Verloock, Leen; Goeminne, Francis; Vermeeren, Gönter; Martens, Luc

    2012-02-01

    In situ electromagnetic (EM) radio frequency (RF) exposure to base stations of emerging wireless technologies is assessed at 311 locations, 68 indoor and 243 outdoor, spread over 35 areas in three European countries (Belgium, The Netherlands, and Sweden) by performing narrowband spectrum analyzer measurements. The locations are selected to characterize six different environmental categories (rural, residential, urban, suburban, office, and industrial). The maximal total field value was measured in a residential environment and equal to 3.9 V m(-1), mainly due to GSM900 signals. Exposure ratios for maximal electric field values, with respect to ICNIRP reference levels, range from 0.5% (WiMAX) to 9.3% (GSM900) for the 311 measurement locations. Exposure ratios for total field values vary from 3.1% for rural environments to 9.4% for residential environments. Exposures are lognormally distributed and are the lowest in rural environments and the highest in urban environments. Highest median exposures were obtained in urban environments (0.74 V m(-1)), followed by office (0.51 V m(-1)), industrial (0.49 V m(-1)), suburban (0.46 V m(-1)), residential (0.40 V m(-1)), and rural (0.09 V m(-1)) environments. The average contribution to the total electric field is more than 60% for GSM. Except for the rural environment, average contributions of UMTS-HSPA are more than 3%. Contributions of the emerging technologies LTE and WiMAX are on average less than 1%. The dominating outdoor source is GSM900 (95 percentile of 1.9 V m(-1)), indoor DECT dominates (95 percentile of 1.5 V m(-1)).

  10. Internal dose assessment of 210Po using biokinetic modeling and urinary excretion measurement

    PubMed Central

    Gerstmann, Udo; Giussani, Augusto; Oeh, Uwe; Paretzke, Herwig G.

    2007-01-01

    The mysterious death of Mr. Alexander Litvinenko who was most possibly poisoned by Polonium-210 (210Po) in November 2006 in London attracted the attention of the public to the kinetics, dosimetry and the risk of this high radiotoxic isotope in the human body. In the present paper, the urinary excretion of seven persons who were possibly exposed to traces of 210Po was monitored. The values measured in the GSF Radioanalytical Laboratory are in the range of natural background concentration. To assess the effective dose received by those persons, the time-dependence of the organ equivalent dose and the effective dose after acute ingestion and inhalation of 210Po were calculated using the biokinetic model for polonium (Po) recommended by the International Commission on Radiological Protection (ICRP) and the one recently published by Leggett and Eckerman (L&E). The daily urinary excretion to effective dose conversion factors for ingestion and inhalation were evaluated based on the ICRP and L&E models for members of the public. The ingestion (inhalation) effective dose per unit intake integrated over one day is 1.7 × 10−8 (1.4 × 10−7) Sv Bq−1, 2.0 × 10−7 (9.6 × 10−7) Sv Bq−1 over 10 days, 5.2 × 10−7 (2.0 × 10−6) Sv Bq−1 over 30 days and 1.0 × 10−6 (3.0 × 10−6) Sv Bq−1 over 100 days. The daily urinary excretions after acute ingestion (inhalation) of 1 Bq of 210Po are 1.1 × 10−3 (1.0 × 10−4) on day 1, 2.0 × 10−3 (1.9 × 10−4) on day 10, 1.3 × 10−3 (1.7 × 10−4) on day 30 and 3.6 × 10−4 (8.3 × 10−5) Bq d−1 on day 100, respectively. The resulting committed effective doses range from 2.1 × 10−3 to 1.7 × 10−2 mSv by an assumption of ingestion and from 5.5 × 10−2 to 4.5 × 10−1 mSv by inhalation. For the case of Mr. Litvinenko, the mean organ absorbed dose as a function of time was calculated using both the above stated models. The red bone marrow, the

  11. 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....

  12. Radioiodine in the Savannah River Site environment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kantelo, M.V.; Bauer, L.R.; Marter, W.L.

    1993-01-15

    Radioiodine, which is the collective term for all radioactive isotopes of the element iodine, is formed at the Savannah River Site (SRS) principally as a by-product of nuclear reactor operations. Part of the radioiodine is released to the environment during reactor and reprocessing operations at the site. The purpose of this report is to provide an introduction to radioiodine production and disposition, its status in the environment, and the radiation dose and health risks as a consequence of its release to the environment around the Savannah River Plant. A rigorous dose reconstruction study is to be completed by thee Centermore » for Disease Control during the 1990s.« less

  13. Development of an Instrument for Assessing Senior High School Students' Preferred and Perceived Laboratory Classroom Environment

    ERIC Educational Resources Information Center

    Hsiao, Chien-Hua; Wu, Ying-Tien; Lin, Chung-Yen; Wong, Terrence William; Fu, Hsieh-Hai; Yeh, Ting-Kuang; Chang, Chung-Yen

    2014-01-01

    This study aimed to develop an instrument, named the inquiry-based laboratory classroom environment instrument (ILEI), for assessing senior high-school science students' preferred and perceived laboratory environment. A total of 262 second-year students, from a senior-high school in Taiwan, were recruited for this study. Four stages were included…

  14. International Arctic Seas Assessment Project.

    PubMed

    Sjöblom, K L; Salo, A; Bewers, J M; Cooper, J; Dyer, R S; Lynn, N M; Mount, M E; Povinec, P P; Sazykina, T G; Schwarz, J; Scott, E M; Sivintsev, Y V; Tanner, J E; Warden, J M; Woodhead, D

    1999-09-30

    The International Atomic Energy Agency responded to the news that the former Soviet Union had dumped radioactive wastes in the shallow waters of the Arctic Seas, by launching the International Arctic Seas Assessment Project in 1993. The project had two objectives: to assess the risks to human health and to the environment associated with the radioactive wastes dumped in the Kara and Barents Seas; and to examine possible remedial actions related to the dumped wastes and to advise on whether they are necessary and justified. The current radiological situation in the Arctic waters was examined to assess whether there is any evidence for releases from the dumped waste. Potential future releases from the dumped wastes were predicted, concentrating on the high-level waste objects containing the major part of the radionuclide inventory of the wastes. Environmental transport of released radionuclides was modelled and the associated radiological impact on humans and the biota was assessed. The feasibility, costs and benefits of possible remedial measures applied to a selected high-level waste object were examined. Releases from identified dumped objects were found to be small and localised to the immediate vicinity of the dumping sites. Projected future annual doses to members of the public in typical local population groups were very small, less than 1 microSv--corresponding to a trivial risk. Projected future doses to a hypothetical group of military personnel patrolling the foreshore of the fjords in which wastes have been dumped were higher, up to 4 mSv/year, which still is of the same order as the average annual natural background dose. Moreover, since any of the proposed remedial actions were estimated to cost several million US$ to implement, remediation was not considered justified on the basis of potentially removing a collective dose of 10 man Sv. Doses calculated to marine fauna were insignificant, orders of magnitude below those at which detrimental effects on

  15. Assessing a VR-based learning environment for anatomy education.

    PubMed

    Hoffman, H; Murray, M; Hettinger, L; Viirre, E

    1998-01-01

    The purpose of the research proposed herein is to develop an empirical, methodological tool for the assessment of visual depth perception in virtual environments (VEs). Our goal is to develop and employ a behaviorally-based method for assessing the impact of VE design features on the perception of visual depth as indexed by the performance of fundamental perceptual-motor activities. Specifically, in this experiment we will assess the affect of two dimensions of VE system design--(1) viewing condition or "level of immersion", and (2) layout/design of the VE--on the performance of an engaging, game-like task. The characteristics of the task to be employed are as follows--(1) it places no demands on cognition in the form of problem solving, retrieval of previously learned information, or other analytic activity in order to assure that (2) variations in task performance can be exclusively attributed to the extent to which the experimental factors influence visual depth perception. Subjects' performance will be assessed in terms of the speed and accuracy of task performance, as well as underlying dimensions of performance such as workload, fatigue, and physiological well being (i.e., cybersickness). The results of this experiment will provide important information on the effect of VE immersion and other VE design issues on human perception and performance. Further development, refinement, and validation of this behaviorally-based methodology will be pursued to provide user-centered design criteria for the design and use of VE systems.

  16. The relevance of image quality indices for dose optimization in abdominal multi-detector row CT in children: experimental assessment with pediatric phantoms

    NASA Astrophysics Data System (ADS)

    Brisse, H. J.; Brenot, J.; Pierrat, N.; Gaboriaud, G.; Savignoni, A.; DeRycke, Y.; Neuenschwander, S.; Aubert, B.; Rosenwald, J.-C.

    2009-04-01

    This study assessed and compared various image quality indices in order to manage the dose of pediatric abdominal MDCT protocols and to provide guidance on dose reduction. PMMA phantoms representing average body diameters at birth, 1 year, 5 years, 10 years and 15 years of age were scanned in a four-channel MDCT with a standard pediatric abdominal CT protocol. Image noise (SD, standard deviation of CT number), noise derivative (ND, derivative of the function of noise with respect to dose) and contrast-to-noise ratio (CNR) were measured. The 'relative' low-contrast detectability (rLCD) was introduced as a new quantity to adjust LCD to the various phantom diameters on the basis of the LCD1% assessed in a Catphan® phantom and a constant central absorbed dose. The required variations of CTDIvol16 with respect to phantom size were analyzed in order to maintain each image quality index constant. The use of a fixed SD or CNR level leads to major dose ratios between extreme patient sizes (factor 22.7 to 44 for SD, 31.7 to 51.5 for CNR2.8%), whereas fixed ND and rLCD result in acceptable dose ratios ranging between factors of 2.9 and 3.9 between extreme phantom diameters. For a 5-9 mm rLCD1%, adjusted ND values range between -0.84 and -0.11 HU mGy-1. Our data provide guidance on dose reduction on the basis of patient dimensions and the required rLCD (e.g., to get a constant 7 mm rLCD1% for abdominal diameters of 10, 13, 16, 20 and 25 cm, tube current-time product should be adjusted in order to obtain CTDIvol16 values of 6.2, 7.2, 8.8, 11.6 and 17.7 mGy, respectively).

  17. Assessment of Mean Glandular Dose in Mammography System with Different Anode-Filter Combinations Using MCNP Code.

    PubMed

    Gholamkar, Lida; Mowlavi, Ali Asghar; Sadeghi, Mahdi; Athari, Mitra

    2016-10-01

    X-ray mammography is one of the general methods for early detection of breast cancer. Since glandular tissue in the breast is sensitive to radiation and it increases the risk of cancer, the given dose to the patient is very important in mammography. The aim of this study was to determine the average absorbed dose of X-ray radiation in the glandular tissue of the breast during mammography examinations as well as investigating factors that influence the mean glandular dose (MGD). One of the precise methods for determination of MGD absorbed by the breast is Monte Carlo simulation method which is widely used to assess the dose. We studied some different X-ray sources and exposure factors that affect the MGD. "Midi-future" digital mammography system with amorphous-selenium detector was simulated using the Monte Carlo N-particle extended (MCNPX) code. Different anode/filter combinations such as tungsten/silver (W/Ag), tungsten/rhodium (W/Rh), and rhodium/aluminium (Rh/Al) were simulated in this study. The voltage of X-ray tube ranged from 24 kV to 32 kV with 2 kV intervals and the breast phantom thickness ranged from 3 to 8 cm, and glandular fraction g varied from 10% to 100%. MGD was measured for different anode/filter combinations and the effects of changing tube voltage, phantom thickness, combination and glandular breast tissue on MGD were studied. As glandular g and X-ray tube voltage increased, the breast dose increased too, and the increase of breast phantom thickness led to the decrease of MGD. The obtained results for MGD were consistent with the result of Boone et al. that was previously reported. By comparing the results, we saw that W/Rh anode/filter combination is the best choice in breast mammography imaging because of the lowest delivered dose in comparison with W/Ag and Rh/Al. Moreover, breast thickness and g value have significant effects on MGD.

  18. Assessment of Mean Glandular Dose in Mammography System with Different Anode-Filter Combinations Using MCNP Code

    PubMed Central

    Gholamkar, Lida; Mowlavi, Ali Asghar; Sadeghi, Mahdi; Athari, Mitra

    2016-01-01

    Background X-ray mammography is one of the general methods for early detection of breast cancer. Since glandular tissue in the breast is sensitive to radiation and it increases the risk of cancer, the given dose to the patient is very important in mammography. Objectives The aim of this study was to determine the average absorbed dose of X-ray radiation in the glandular tissue of the breast during mammography examinations as well as investigating factors that influence the mean glandular dose (MGD). One of the precise methods for determination of MGD absorbed by the breast is Monte Carlo simulation method which is widely used to assess the dose. Materials and Methods We studied some different X-ray sources and exposure factors that affect the MGD. “Midi-future” digital mammography system with amorphous-selenium detector was simulated using the Monte Carlo N-particle extended (MCNPX) code. Different anode/filter combinations such as tungsten/silver (W/Ag), tungsten/rhodium (W/Rh), and rhodium/aluminium (Rh/Al) were simulated in this study. The voltage of X-ray tube ranged from 24 kV to 32 kV with 2 kV intervals and the breast phantom thickness ranged from 3 to 8 cm, and glandular fraction g varied from 10% to 100%. Results MGD was measured for different anode/filter combinations and the effects of changing tube voltage, phantom thickness, combination and glandular breast tissue on MGD were studied. As glandular g and X-ray tube voltage increased, the breast dose increased too, and the increase of breast phantom thickness led to the decrease of MGD. The obtained results for MGD were consistent with the result of Boone et al. that was previously reported. Conclusion By comparing the results, we saw that W/Rh anode/filter combination is the best choice in breast mammography imaging because of the lowest delivered dose in comparison with W/Ag and Rh/Al. Moreover, breast thickness and g value have significant effects on MGD. PMID:27895876

  19. Assessment of thermal environments: working conditions in the portuguese glass industry

    PubMed Central

    OLIVEIRA, A. Virgílio M.; GASPAR, Adélio R.; RAIMUNDO, António M.; QUINTELA, Divo A.

    2017-01-01

    The objective of the present contribution is to assess the exposure to hot thermal environments in the Portuguese glass industry. For this purpose a field survey was carried out and the measurements took place in industrial units - five industries and nineteen workplaces were considered–so all the results are based on real working conditions. In order to assess the level of heat exposure the Wet Bulb Globe Temperature (WBGT) index and the Predicted Heat Strain (PHS) model, defined in ISO Standards 7243 (1989) and 7933 (2004), respectively, were used. According to the WBGT index, the results show that almost 80% of the workplaces under analysis are prone to heat stress conditions. If the PHS model is considered, the results highlight that the predicted and the maximum sweat rates present equal values in about 40% of the workplaces. In addition, in almost 25% of the workplaces the estimated rectal temperature was higher than 38°C, just for an exposure period of one hour. Thus, the present study brings to light the characteristics of the glass industry in terms of the occupational exposure to hot environments and places this activity sector as one of the most difficult to deal with. PMID:28824045

  20. EPR/PTFE dosimetry for test reactor environments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vehar, D.W.; Griffin, P.J.; Quirk, T.J.

    2011-07-01

    The use of Electron Paramagnetic Resonance (EPR) spectroscopy with materials such as alanine is well established as a technique for measurement of ionizing radiation absorbed dose in photon and electron fields such as Co-60, high-energy bremsstrahlung and electron-beam fields [1]. In fact, EPR/Alanine dosimetry has become a routine transfer standard for national standards bodies such as NIST and NPL. In 1992 the Radiation Metrology Laboratory (RML) at Sandia National Laboratories implemented EPR/Alanine capabilities for use in routine and calibration activities at its Co-60 and pulsed-power facilities. At that time it also investigated the usefulness of the system for measurement ofmore » absorbed dose in the mixed neutron/photon environments of reactors such as the Sandia Pulsed Reactor and the Annular Core Research Reactor used for hardness testing of electronics. The RML concluded that the neutron response of alanine was a sufficiently high fraction of the overall dosimeter response that the resulting uncertainties in the photon dose would be unacceptably large for silicon-device testing. However, it also suggested that non-hydrogenous materials such as polytetrafluoroethylene (PTFE) would exhibit smaller neutron response and might be useful in mixed environments. Preliminary research with PTFE in photon environments indicated considerable promise, but further development was not pursued at that time. Because of renewed interest in absorbed dose measurements that could better define the individual contributions of photon and neutron components to the overall dose delivered to a test object, the RML has re-initiated the development of an EPR/PTFE dosimetry system. This effort consists of three stages: 1) Identification of PTFE materials that may be suitable for dosimetry applications. It was speculated that the inconsistency of EPR signatures in the earlier samples may have been due to variability in PTFE manufacturing processes. 2) Characterization of

  1. Mechanism-based risk assessment strategy for drug-induced cholestasis using the transcriptional benchmark dose derived by toxicogenomics.

    PubMed

    Kawamoto, Taisuke; Ito, Yuichi; Morita, Osamu; Honda, Hiroshi

    2017-01-01

    Cholestasis is one of the major causes of drug-induced liver injury (DILI), which can result in withdrawal of approved drugs from the market. Early identification of cholestatic drugs is difficult due to the complex mechanisms involved. In order to develop a strategy for mechanism-based risk assessment of cholestatic drugs, we analyzed gene expression data obtained from the livers of rats that had been orally administered with 12 known cholestatic compounds repeatedly for 28 days at three dose levels. Qualitative analyses were performed using two statistical approaches (hierarchical clustering and principle component analysis), in addition to pathway analysis. The transcriptional benchmark dose (tBMD) and tBMD 95% lower limit (tBMDL) were used for quantitative analyses, which revealed three compound sub-groups that produced different types of differential gene expression; these groups of genes were mainly involved in inflammation, cholesterol biosynthesis, and oxidative stress. Furthermore, the tBMDL values for each test compound were in good agreement with the relevant no observed adverse effect level. These results indicate that our novel strategy for drug safety evaluation using mechanism-based classification and tBMDL would facilitate the application of toxicogenomics for risk assessment of cholestatic DILI.

  2. A study of fault prediction and reliability assessment in the SEL environment

    NASA Technical Reports Server (NTRS)

    Basili, Victor R.; Patnaik, Debabrata

    1986-01-01

    An empirical study on estimation and prediction of faults, prediction of fault detection and correction effort, and reliability assessment in the Software Engineering Laboratory environment (SEL) is presented. Fault estimation using empirical relationships and fault prediction using curve fitting method are investigated. Relationships between debugging efforts (fault detection and correction effort) in different test phases are provided, in order to make an early estimate of future debugging effort. This study concludes with the fault analysis, application of a reliability model, and analysis of a normalized metric for reliability assessment and reliability monitoring during development of software.

  3. Safety assessment and single-dose toxicokinetics of the flavouring agent myricitrin in Sprague-Dawley rats.

    PubMed

    Maronpot, Robert R; Koyanagi, Mihoko; Davis, Jeffrey; Recio, Leslie; Marbury, Dean; Boyle, Molly; Hayashi, Shim-mo

    2015-01-01

    Myricitrin, a flavonol rhamnoside of myricetin extracted from the Chinese bayberry (Myrica rubra Siebold) plant, has been used in Japan since 1992 as a flavour modifier in snack foods, dairy products, and beverages. It is affirmed as generally recognised as safe (GRAS) by the US Flavour and Extract Manufacturer Association (FEMA) and is considered safe by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) at current estimated dietary exposures. In anticipation of expanded marketing, 97% pure myricitrin was fed to male and female Sprague-Dawley rats at dietary concentrations of 0.5%, 1.5% and 5.0% in a 90-day toxicity study. There was increased food consumption and decreased body weight gain in males exposed to 5% myricitrin. Blood values were within laboratory reference ranges except for mean increases in basophils in low- and high-dose males and serum phosphorus in high-dose males. In the absence of abnormal clinical or histopathological changes, these changes are not considered adverse. Based on the 90-day rat toxicity study, the no observed adverse effect level (NOAEL) is 2926 mg kg(-1) day(-1) in males and 3197 mg kg(-1) day(-1) in females. Gavage administration of myricitrin resulted in blood levels of myricitrin within 1 h after single oral doses of 250, 500 or 1000 mg kg(-1) body weight, indicating direct absorption of the glycosylated form of this flavonoid. Blood levels of myricetin, a metabolite of myricitrin, were not present in rats dosed orally with 1.6 mg kg(-1) myricetin, but were present only at 12 or 24 h in one of five, in three of five, and in four of five rats dosed with 250, 500 and 1000 mg myricitrin kg(-1) body weight, respectively, possibly a result of hepatic conversion of myricitrin to myricetin and enterohepatic recirculation of the resulting myricetin. The current studies further support prior safety assessments of myricitrin as a food flavouring.

  4. Statistic and dosimetric criteria to assess the shift of the prescribed dose for lung radiotherapy plans when integrating point kernel models in medical physics: are we ready?

    PubMed

    Chaikh, Abdulhamid; Balosso, Jacques

    2016-12-01

    To apply the statistical bootstrap analysis and dosimetric criteria's to assess the change of prescribed dose (PD) for lung cancer to maintain the same clinical results when using new generations of dose calculation algorithms. Nine lung cancer cases were studied. For each patient, three treatment plans were generated using exactly the same beams arrangements. In plan 1, the dose was calculated using pencil beam convolution (PBC) algorithm turning on heterogeneity correction with modified batho (PBC-MB). In plan 2, the dose was calculated using anisotropic analytical algorithm (AAA) and the same PD, as plan 1. In plan 3, the dose was calculated using AAA with monitor units (MUs) obtained from PBC-MB, as input. The dosimetric criteria's include MUs, delivered dose at isocentre (Diso) and calculated dose to 95% of the target volume (D95). The bootstrap method was used to assess the significance of the dose differences and to accurately estimate the 95% confidence interval (95% CI). Wilcoxon and Spearman's rank tests were used to calculate P values and the correlation coefficient (ρ). Statistically significant for dose difference was found using point kernel model. A good correlation was observed between both algorithms types, with ρ>0.9. Using AAA instead of PBC-MB, an adjustment of the PD in the isocentre is suggested. For a given set of patients, we assessed the need to readjust the PD for lung cancer using dosimetric indices and bootstrap statistical method. Thus, if the goal is to keep on with the same clinical results, the PD for lung tumors has to be adjusted with AAA. According to our simulation we suggest to readjust the PD by 5% and an optimization for beam arrangements to better protect the organs at risks (OARs).

  5. NOAEL-dose of a neonicotinoid pesticide, clothianidin, acutely induce anxiety-related behavior with human-audible vocalizations in male mice in a novel environment.

    PubMed

    Hirano, Tetsushi; Yanai, Shogo; Takada, Tadashi; Yoneda, Naoki; Omotehara, Takuya; Kubota, Naoto; Minami, Kiichi; Yamamoto, Anzu; Mantani, Youhei; Yokoyama, Toshifumi; Kitagawa, Hiroshi; Hoshi, Nobuhiko

    2018-01-05

    Neonicotinoids are novel systemic pesticides acting as agonists on the nicotinic acetylcholine receptors (nAChRs) of insects. Experimental studies have revealed that neonicotinoids pose potential risks for the nervous systems of non-target species, but the brain regions responsible for their behavioral effects remain incompletely understood. This study aimed to assess the neurobehavioral effects of clothianidin (CTD), a later neonicotinoid developed in 2001 and widely used worldwide, and to explore the target regions of neonicotinoids in the mammalian brain. A single-administration of 5 or 50mg/kg CTD to male C57BL/6N mice at or below the no-observed-adverse-effect level (NOAEL) induced an acute increase in anxiety during the elevated plus-maze test. In addition, mice in the CTD-administered group spontaneously emitted human-audible vocalizations (4-16kHz), which are behavioral signs of aversive emotions, and showed increased numbers of c-fos immunoreactive cells in the paraventricular thalamic nucleus and dentate gyrus of the hippocampus. In conclusion, mice exposed to NOAEL-dose CTD would be rendered vulnerable to a novel environment via the activation of thalamic and hippocampal regions related to stress responses. These findings should provide critical insight into the neurobehavioral effects of neonicotinoids on mammals. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Evaluation of the Comet Assay for Assessing the Dose-Response Relationship of DNA Damage Induced by Ionizing Radiation

    PubMed Central

    Wang, Yan; Xu, Chang; Du, Li Qing; Cao, Jia; Liu, Jian Xiang; Su, Xu; Zhao, Hui; Fan, Fei-Yue; Wang, Bing; Katsube, Takanori; Fan, Sai Jun; Liu, Qiang

    2013-01-01

    Dose- and time-response curves were combined to assess the potential of the comet assay in radiation biodosimetry. The neutral comet assay was used to detect DNA double-strand breaks in lymphocytes caused by γ-ray irradiation. A clear dose-response relationship with DNA double-strand breaks using the comet assay was found at different times after irradiation (p < 0.001). A time-response relationship was also found within 72 h after irradiation (p < 0.001). The curves for DNA double-strand breaks and DNA repair in vitro of human lymphocytes presented a nice model, and a smooth, three-dimensional plane model was obtained when the two curves were combined. PMID:24240807

  7. A correlation study of eye lens dose and personal dose equivalent for interventional cardiologists.

    PubMed

    Farah, J; Struelens, L; Dabin, J; Koukorava, C; Donadille, L; Jacob, S; Schnelzer, M; Auvinen, A; Vanhavere, F; Clairand, I

    2013-12-01

    This paper presents the dosimetry part of the European ELDO project, funded by the DoReMi Network of Excellence, in which a method was developed to estimate cumulative eye lens doses for past practices based on personal dose equivalent values, H(p)(10), measured above the lead apron at several positions at the collar, chest and waist levels. Measurement campaigns on anthropomorphic phantoms were carried out in typical interventional settings considering different tube projections and configurations, beam energies and filtration, operator positions and access routes and using both mono-tube and biplane X-ray systems. Measurements showed that eye lens dose correlates best with H(p)(10) measured on the left side of the phantom at the level of the collar, although this correlation implicates high spreads (41 %). Nonetheless, for retrospective dose assessment, H(p)(10) records are often the only option for eye dose estimates and the typically used chest left whole-body dose measurement remains useful.

  8. Dose-response assessment for influenza A virus based on data sets of infection with its live attenuated reassortants.

    PubMed

    Watanabe, Toru; Bartrand, Timothy A; Omura, Tatsuo; Haas, Charles N

    2012-03-01

    Reported data sets on infection of volunteers challenged with wild-type influenza A virus at graded doses are few. Alternatively, we aimed at developing a dose-response assessment for this virus based on the data sets for its live attenuated reassortants. Eleven data sets for live attenuated reassortants that were fit to beta-Poisson and exponential dose-response models. Dose-response relationships for those reassortants were characterized by pooling analysis of the data sets with respect to virus subtype (H1N1 or H3N2), attenuation method (cold-adapted or avian-human gene reassortment), and human age (adults or children). Furthermore, by comparing the above data sets to a limited number of reported data sets for wild-type virus, we quantified the degree of attenuation of wild-type virus with gene reassortment and estimated its infectivity. As a result, dose-response relationships of all reassortants were best described by a beta-Poisson model. Virus subtype and human age were significant factors determining the dose-response relationship, whereas attenuation method affected only the relationship of H1N1 virus infection to adults. The data sets for H3N2 wild-type virus could be pooled with those for its reassortants on the assumption that the gene reassortment attenuates wild-type virus by at least 63 times and most likely 1,070 times. Considering this most likely degree of attenuation, 10% infectious dose of H3N2 wild-type virus for adults was estimated at 18 TCID50 (95% CI = 8.8-35 TCID50). The infectivity of wild-type H1N1 virus remains unknown as the data set pooling was unsuccessful. © 2011 Society for Risk Analysis.

  9. Development of the voxel computational phantoms of pediatric patients and their application to organ dose assessment

    NASA Astrophysics Data System (ADS)

    Lee, Choonik

    A series of realistic voxel computational phantoms of pediatric patients were developed and then used for the radiation risk assessment for various exposure scenarios. The high-resolution computed tomographic images of live patients were utilized for the development of the five voxel phantoms of pediatric patients, 9-month male, 4-year female, 8-year female, 11-year male, and 14-year male. The phantoms were first developed as head and torso phantoms and then extended into whole body phantoms by utilizing computed tomographic images of a healthy adult volunteer. The whole body phantom series was modified to have the same anthropometrics with the most recent reference data reported by the international commission on radiological protection. The phantoms, named as the University of Florida series B, are the first complete set of the pediatric voxel phantoms having reference organ masses and total heights. As part of the dosimetry study, the investigation on skeletal tissue dosimetry methods was performed for better understanding of the radiation dose to the active bone marrow and bone endosteum. All of the currently available methodologies were inter-compared and benchmarked with the paired-image radiation transport model. The dosimetric characteristics of the phantoms were investigated by using Monte Carlo simulation of the broad parallel beams of external phantom in anterior-posterior, posterior-anterior, left lateral, right lateral, rotational, and isotropic angles. Organ dose conversion coefficients were calculated for extensive photon energies and compared with the conventional stylized pediatric phantoms of Oak Ridge National Laboratory. The multi-slice helical computed tomography exams were simulated using Monte Carlo simulation code for various exams protocols, head, chest, abdomen, pelvis, and chest-abdomen-pelvis studies. Results have found realistic estimates of the effective doses for frequently used protocols in pediatric radiology. The results were very

  10. Diagnostic doses and times for Phlebotomus papatasi and Lutzomyia longipalpis sand flies (Diptera: Psychodidae: Phlebotominae) using the CDC bottle bioassay to assess insecticide resistance.

    PubMed

    Denlinger, David S; Creswell, Joseph A; Anderson, J Laine; Reese, Conor K; Bernhardt, Scott A

    2016-04-15

    Insecticide resistance to synthetic chemical insecticides is a worldwide concern in phlebotomine sand flies (Diptera: Psychodidae), the vectors of Leishmania spp. parasites. The CDC bottle bioassay assesses resistance by testing populations against verified diagnostic doses and diagnostic times for an insecticide, but the assay has been used limitedly with sand flies. The objective of this study was to determine diagnostic doses and diagnostic times for laboratory Lutzomyia longipalpis (Lutz & Nieva) and Phlebotomus papatasi (Scopoli) to ten insecticides, including pyrethroids, organophosphates, carbamates, and DDT, that are used worldwide to control vectors. Bioassays were conducted in 1,000-ml glass bottles each containing 10-25 sand flies from laboratory colonies of L. longipalpis or P. papatasi. Four pyrethroids, three organophosphates, two carbamates and one organochlorine, were evaluated. A series of concentrations were tested for each insecticide, and four replicates were conducted for each concentration. Diagnostic doses were determined only during the exposure bioassay for the organophosphates and carbamates. For the pyrethroids and DDT, diagnostic doses were determined for both the exposure bioassay and after a 24-hour recovery period. Both species are highly susceptible to the carbamates as their diagnostic doses are under 7.0 μg/ml. Both species are also highly susceptible to DDT during the exposure assay as their diagnostic doses are 7.5 μg/ml, yet their diagnostic doses for the 24-h recovery period are 650.0 μg/ml for Lu. longipalpis and 470.0 μg/ml for P. papatasi. Diagnostic doses and diagnostic times can now be incorporated into vector management programs that use the CDC bottle bioassay to assess insecticide resistance in field populations of Lu. longipalpis and P. papatasi. These findings provide initial starting points for determining diagnostic doses and diagnostic times for other sand fly vector species and wild populations using the CDC

  11. [Methodology for an assessment of derived radiation levels for agrocenoses].

    PubMed

    Udalova, A A; Ul'ianenko, L N; Aleksakhin, R M; Geras'kin, S A; Filipas, A S

    2010-01-01

    Radiation protection of agrarian ecosystems should be considered as an integral part of a system for radiation protection of environment, with a special concern to agroecosystems' features. A methodology is proposed for an assessment of maximum permissible doses of radiation impact for agrocenoses based on an unified analysis of available data about effects of radiation in cultivated plants. It is considered as a component of radiation protection system for agricultural ecosystems. Critical doses and dose rates are estimated for crops under different exposure situations. It is shown that doses that could result in decreasing indexes of productivity and survival for main crops below 50% are unlikely up to 170-200 Gy and 15-17 Gy at an acute exposure of dormant seeds and vegetative plants, correspondingly. At chronic exposure, above 10% loss of productivity in crops is not expected at dose rates below 3-10 mGy/h.

  12. [Diagnosis of cerebral metastasis with standard dose gadobutrol vs. a high dose protocol. Intraindividual evaluation of a phase II high dose study].

    PubMed

    Vogl, T J; Friebe, C E; Balzer, T; Mack, M G; Steiner, S; Schedel, H; Pegios, W; Lanksch, W; Banzer, D; Felix, R

    1995-08-01

    To assess the effectiveness and safety of normal and high doses of Gadobutrol versus a standard dose of Gadolinium DTPA in the MR evaluation of patients with brain metastases. In a clinical phase-II study 20 patients who had been diagnosed as having brain metastases with CT or MRT were studied prospectively with Gadobutrol, a new nonionic, low osmolality contrast agent. Each patient received an initial injection of 0.1 mmol/kg body weight and an additional dose of 0.2 mmol/kg Gadobutrol 10 min later. Spin-echo images were obtained before and after the two applications of Gadobutrol. Dynamic scanning (Turbo-FLASH) was performed for 3 min after each injection of the contrast agent. Both quantitative and qualitative data were intraindividually evaluated. The primary tumor was a bronchial carcinoma in 11 cases; in 9 other cases there were different primary tumors. Forty-eight hours after the use of Gadobutrol there were no adverse signs in the clinical examination, vital signs or blood and urine chemistry. Statistical analysis (Friedman test and Wilcoxon test) of the C/N ratios between tumor and white matter, percentage enhancement, and visual assessment rating revealed statistically significant superiority of high-dose Gadobutrol injection in comparison to the standard dose. The percentage enhancement increased on average from 104% after 0.1 mmol/kg to 162% after 0.3 mmol/kg Gadobutrol. Qualitative delineation and contrast of the lesions increased significantly. The use of high-dose Gadobutrol improved the detection of 36 additional lesions in 6 patients. The first in vivo results prove the excellent contrast capacity of the nonionic contrast agent Gadobutrol for the diagnosis of intracerebral metastases.

  13. [Assessment of the impact of psycho-social environment on toddlers' physical and neuropsychic development].

    PubMed

    Petrariu, F D; Gavăt, Viorica; Amarandei, Magda Elena

    2007-01-01

    Psycho-social environment is influencing directly toddler's development, with a major impact in the first three years of life. Family is the first social environment for the infant, and later for toddler, and depending to the quality of this relation will evolve the adult. To assess the impact of psycho-social environment on the toddler's development. We have analyzed by using a questionnaire a number of 200 families, in order to assess their level of environmental risk and to correlate it with the toddlers' development. The highest risk scores were obtained by families who sent the toddler in a foster home, followed by the families who use a day care center, and at last by the families where toddler remains in the family's home till he is 3 years old. 51.66% of the toddlers who goes in a day care center and 85% of the toddlers who are sent to foster home are exposed to a relative risk lower by 2.7 times to be retarded compared to the situation of remaining in the natural home. On the other hand, in family environment with a mild risk there are significant more disharmonic children than in the families with a lower risk score (p = 0.0452). The toddler's chances to evolve, by physical perspective, negatively in institutional environment are significantly higher if he comes from a family with mild risk score than in a family with a lower risk score (p = 0.0157). In every life environment where lives a toddler, confronted with specific problems, should take immediate action the general practitioner, the child development specialist and the environmental health expert, in a coordinate manner, to identify and correct all the aspects who may disturb the normal evolution of the toddler's growth and development.

  14. Gene–environment interaction in tobacco-related cancers

    PubMed Central

    Taioli, Emanuela

    2008-01-01

    This review summarizes the carcinogenic effects of tobacco smoke and the basis for interaction between tobacco smoke and genetic factors. Examples of published papers on gene–tobacco interaction and cancer risk are presented. The assessment of gene–environment interaction in tobacco-related cancers has been more complex than originally expected for several reasons, including the multiplicity of genes involved in tobacco metabolism, the numerous substrates metabolized by the relevant genes and the interaction of smoking with other metabolic pathways. Future studies on gene–environment interaction and cancer risk should include biomarkers of smoking dose, along with markers of quantitative historical exposure to tobacco. Epigenetic studies should be added to classic genetic analyses, in order to better understand gene–environmental interaction and individual susceptibility. Other metabolic pathways in competition with tobacco genetic metabolism/repair should be incorporated in epidemiological studies to generate a more complete picture of individual cancer risk associated with environmental exposure to carcinogens. PMID:18550573

  15. Using Social Simulations to Assess and Train Potential Leaders to Make Effective Decisions in Turbulent Environments

    ERIC Educational Resources Information Center

    Hunsaker, L. Phillip

    2007-01-01

    Purpose: The purpose of this paper is to describe two social simulations created to assess leadership potential and train leaders to make effective decisions in turbulent environments. One is set in the novel environment of a lunar moon colony and the other is a military combat command. The research generated from these simulations for assessing…

  16. SU-E-J-101: Retroactive Calculation of TLD and Film Dose in Anthropomorphic Phantom as Assessment of Updated TPS Performance

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alkhatib, H; Oves, S

    Purpose: To demonstrate a quick and comprehensive method verifying the accuracy of the updated dose model by recalculating dose distribution in an anthropomorphic phantom with a new version of the TPS and comparing the results to measured values. Methods: CT images and IMRT plan of an RPC anthropomorphic head phantom, previously calculated by Pinnacle 9.0, was re-computed using Pinnacle 9.2 and 9.6. The dosimeters within the phantom include four TLD capsules representing a primary PTV, two TLD capsules representing a secondary PTV, and two TLD capsules representing an organ at risk. Also included were three sheets of Gafchromic film. Performancemore » of the updated TPS version was assessed by recalculating point doses and dose profiles corresponding to TLD and film position respectively and then comparing the results to reported values by the RPC. Results: Comparing calculated doses to reported measured doses from the RPC yielded an average disagreement of 1.48%, 2.04% and 2.10% for versions 9.0, 9.2, 9.6 respectively. Computed doses points all meet the RPC's passing criteria with the exception of the point representing the superior organ at risk in version 9.6. However, qualitative analysis of the recalculated dose profiles showed improved agreement with those of the RPC, especially in the penumbra region. Conclusion: This work has demonstrated the calculation results of Pinnacle 9.2 and 9.6 vs 9.0 version. Additionally, this study illustrates a method for the user to gain confidence upgrade to a newer version of the treatment planning system.« less

  17. High- to low-dose extrapolation: critical determinants involved in the dose response of carcinogenic substances.

    PubMed

    Swenberg, J A; Richardson, F C; Boucheron, J A; Deal, F H; Belinsky, S A; Charbonneau, M; Short, B G

    1987-12-01

    Recent investigations on mechanism of carcinogenesis have demonstrated important quantitative relationships between the induction of neoplasia, the molecular dose of promutagenic DNA adducts and their efficiency for causing base-pair mismatch, and the extent of cell proliferation in target organ. These factors are involved in the multistage process of carcinogenesis, including initiation, promotion, and progression. The molecular dose of DNA adducts can exhibit supralinear, linear, or sublinear relationships to external dose due to differences in absorption, biotransformation, and DNA repair at high versus low doses. In contrast, increased cell proliferation is a common phenomena that is associated with exposures to relatively high doses of toxic chemicals. As such, it enhances the carcinogenic response at high doses, but has little effect at low doses. Since data on cell proliferation can be obtained for any exposure scenario and molecular dosimetry studies are beginning to emerge on selected chemical carcinogens, methods are needed so that these critical factors can be utilized in extrapolation from high to low doses and across species. The use of such information may provide a scientific basis for quantitative risk assessment.

  18. APPLICATION OF THE EXPOSURE DOSE ESTIMATING MODEL (ERDEM) TO ASSESSMENT OF DERMAL EXPOSURE IN THE RAT TO MALATHION

    EPA Science Inventory

    APPLICATION OF THE EXPOSURE DOSE ESTIMATING MODEL (ERDEM) TO ASSESSMENT OF DERMAL EXPOSURE IN THE RAT TO MALATHION.
    Evans, M.V1., Power, F.W2., Dary, C.C2., Tornero-Velez, R2., and Blancato, J.N2.
    1 NHEERL, US EPA, ORD, ETD, RTP, NC; 2 NERL, US EPA, ORD, EDRB, LV, NV
    Re...

  19. In vitro and in vivo assessment of platelet function in healthy dogs during administration of a low-dose aspirin regimen.

    PubMed

    Haines, Jillian M; Thomason, John M; Seage, Eileen C; Wills, Robert W; Bulla, Camilo; Lunsford, Kari V; Mackin, Andrew J

    2016-02-01

    To assess the in vitro and in vivo platelet function of healthy dogs during administration of a low-dose aspirin regimen. 16 dogs. Dogs received aspirin (1 mg/kg, PO, q 24 h) for 7 days. Blood and urine samples were collected before (day 1; baseline) and on days 3 and 7 of the low-dose aspirin regimen. Platelet function was evaluated by use of turbidimetric and conventional impedance aggregometry, multiple-electrode impedance aggregometry, a platelet function analyzer (PFA), and determination of urine 11-dehydro-thromboxane B2 concentration. Turbidimetric aggregometry results were compared with the results obtained by the other 4 methods. Fourteen days after cessation of aspirin, platelet-rich plasma was incubated with acetylsalicylic acid and platelet function was assessed by turbidimetric aggregometry to determine whether this technique could accurately identify dogs that responded to the low-dose aspirin regimen. Of the 16 dogs, 13 had turbidimetric and conventional impedance aggregometry results that were decreased by > 25% from baseline on days 3 and 7, and 4 and 7 dogs had PFA closure times > 300 seconds on days 3 and 7, respectively. The median urine 11-dehydro-thromboxane B2 concentration-to-creatinine concentration ratio decreased by 49% between days 1 and 7. Turbidimetric aggregometry results were correlated with conventional impedance aggregometry results. There was poor agreement between the turbidimetric aggregometry and PFA results. The multiple-electrode impedance aggregometry protocol failed to reliably detect aspirin-induced platelet dysfunction. In vitro incubation of platelet-rich plasma with acetylsalicylic acid followed by turbidimetric aggregometry did not predict whether dogs responded to the low-dose aspirin regimen. Results indicated that the response to a low-dose aspirin regimen varied among healthy dogs.

  20. Comparison of the Current Center of Site Annual Neshap Dose Modeling at the Savannah River Site with Other Assessment Methods.

    PubMed

    Minter, Kelsey M; Jannik, G Timothy; Stagich, Brooke H; Dixon, Kenneth L; Newton, Joseph R

    2018-04-01

    The U.S. Environmental Protection Agency (EPA) requires the use of the model CAP88 to estimate the total effective dose (TED) to an offsite maximally exposed individual (MEI) for demonstrating compliance with 40 CFR 61, Subpart H: The National Emission Standards for Hazardous Air Pollutants (NESHAP) regulations. For NESHAP compliance at the Savannah River Site (SRS), the EPA, the U.S. Department of Energy (DOE), South Carolina's Department of Health and Environmental Control, and SRS approved a dose assessment method in 1991 that models all radiological emissions as if originating from a generalized center of site (COS) location at two allowable stack heights (0 m and 61 m). However, due to changes in SRS missions, radiological emissions are no longer evenly distributed about the COS. An area-specific simulation of the 2015 SRS radiological airborne emissions was conducted to compare to the current COS method. The results produced a slightly higher dose estimate (2.97 × 10 mSv vs. 2.22 × 10 mSv), marginally changed the overall MEI location, and noted that H-Area tritium emissions dominated the dose. Thus, an H-Area dose model was executed as a potential simplification of the area-specific simulation by adopting the COS methodology and modeling all site emissions from a single location in H-Area using six stack heights that reference stacks specific to the tritium production facilities within H-Area. This "H-Area Tritium Stacks" method produced a small increase in TED estimates (3.03 × 10 mSv vs. 2.97 × 10 mSv) when compared to the area-specific simulation. This suggests that the current COS method is still appropriate for demonstrating compliance with NESHAP regulations but that changing to the H-Area Tritium Stacks assessment method may now be a more appropriate representation of operations at SRS.

  1. Assessing the Nexus of Built, Natural, and Social Environments and Public Health Outcomes

    NASA Astrophysics Data System (ADS)

    Archer, R.; Alexander, S.; Douglas, J.

    2017-12-01

    This study investigates community-related environmental justice concerns and chemical and non-chemical health stressors from built, natural, and social environments in Southeast Los Angeles (SELA) County and East Oakland, California. The geographical distribution of health outcomes is related to the built and natural environments, as well as impacts from the social environment. A holistic systems view is important in assessing healthy behaviors within a community, because they do not occur in isolation. Geospatial analysis will be performed to integrate a total environment framework and explore the spatial patterns of exposure to chemical and non-chemical stressors and access to health-promoting environments. Geographic Information Systems (GIS) analysis using primary and secondary existing data will be performed to determine how social environments impact exposure to chemical health stressors and access to health-promoting built and natural environments. This project will develop a comprehensive list of health-promoting built and natural environments (e.g., parks and community gardens) and polluting sites (e.g., shipping ports and sources of pollution not included in federal regulatory databases) in East Oakland and SELA. California Department of Public Health and U.S. Decennial Census data will also be included for geospatial analysis to overlay the distribution of air pollution-related morbidities (e.g. asthma, diabetes, and cancer) and access to health-promoting built and natural environments and related community assets, exposure to polluting industries, social disorganization, and public health outcomes in the target areas. This research will help identify the spatial and temporal distribution and cumulative impacts of critical pollution hotspots causing community environmental health impacts. The research team will also map how social environments impact exposure to chemical health stressors and access to health-promoting built and natural environments. The

  2. QSIA--A Web-Based Environment for Learning, Assessing and Knowledge Sharing in Communities

    ERIC Educational Resources Information Center

    Rafaeli, Sheizaf; Barak, Miri; Dan-Gur, Yuval; Toch, Eran

    2004-01-01

    This paper describes a Web-based and distributed system named QSIA that serves as an environment for learning, assessing and knowledge sharing. QSIA--Questions Sharing and Interactive Assignments--offers a unified infrastructure for developing, collecting, managing and sharing of knowledge items. QSIA enhances collaboration in authoring via online…

  3. Thyroid Dose During Neurointerventional Procedures: Does Lead Shielding Reduce the Dose?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shortt, C. P.; Fanning, N. F.; Malone, L.

    2007-09-15

    Purpose. To assess radiation dose to the thyroid in patients undergoing neurointerventional procedures and to evaluate dose reduction to the thyroid by lead shielding. Methods and Materials. A randomized patient study was undertaken to evaluate the dose reduction by thyroid lead shields and assess their practicality in a clinical setting. Sixty-five patients attending for endovascular treatment of arteriovenous malformations (AVMs) and aneurysms were randomized into one of 2 groups a) No Thyroid Shield and b) Thyroid Lead Shield. Two thermoluminescent dosimeters (TLDs) were placed over the thyroid gland (1 on each side) at constant positions on each patient in bothmore » groups. A thyroid lead shield (Pb eq. 0.5 mm) was placed around the neck of patients in the thyroid lead shield group after the neurointerventional radiologist had obtained satisfactory working access above the neck. The total dose-area-product (DAP) value, number and type of digital subtraction angiography (DSA) runs and fluoroscopy time were recorded for all patients. Results. Of the 72 patients who initially attended for neurointerventional procedures, 7 were excluded due to failure to consent or because of procedures involving access to the external carotid circulation. Of the remaining 65 who were randomized, a further 9 were excluded due to; procedureabandonment, unfeasible shield placement or shield interference with the procedure. Patient demographics included mean age of 47.9 yrs (15-74), F:M=1.4:1. Mean fluoroscopy time was 25.9 min. Mean DAP value was 13,134.8 cGy.cm{sup 2} and mean number of DSA runs was 13.4. The mean relative thyroid doses were significantly different (p< 0.001) between the unshielded (7.23 mSv/cGy2 x 105) and shielded groups (3.77 mSv/cGy2 x 105). A mean thyroid dose reduction of 48% was seen in the shielded group versus the unshielded group. Conclusion. Considerable doses to the thyroid are incurred during neurointerventional procedures, highlighting the need for

  4. Dual-resolution dose assessments for proton beamlet using MCNPX 2.6.0

    NASA Astrophysics Data System (ADS)

    Chao, T. C.; Wei, S. C.; Wu, S. W.; Tung, C. J.; Tu, S. J.; Cheng, H. W.; Lee, C. C.

    2015-11-01

    The purpose of this study is to access proton dose distribution in dual resolution phantoms using MCNPX 2.6.0. The dual resolution phantom uses higher resolution in Bragg peak, area near large dose gradient, or heterogeneous interface and lower resolution in the rest. MCNPX 2.6.0 was installed in Ubuntu 10.04 with MPI for parallel computing. FMesh1 tallies were utilized to record the energy deposition which is a special designed tally for voxel phantoms that converts dose deposition from fluence. 60 and 120 MeV narrow proton beam were incident into Coarse, Dual and Fine resolution phantoms with pure water, water-bone-water and water-air-water setups. The doses in coarse resolution phantoms are underestimated owing to partial volume effect. The dose distributions in dual or high resolution phantoms agreed well with each other and dual resolution phantoms were at least 10 times more efficient than fine resolution one. Because the secondary particle range is much longer in air than in water, the dose of low density region may be under-estimated if the resolution or calculation grid is not small enough.

  5. The effectiveness of environment assessment tools to guide refurbishment of Australian residential aged care facilities: A systematic review.

    PubMed

    Neylon, Samantha; Bulsara, Caroline; Hill, Anne-Marie

    2017-06-01

    To determine applicability of environment assessment tools in guiding minor refurbishments of Australian residential aged care facilities. Studies conducted in residential aged care settings using assessment tools which address the physical environment were eligible for inclusion in a systematic review. Given these studies are limited, tools which have not yet been utilised in research settings were also included. Tools were analysed using a critical appraisal screen. Forty-three publications met the inclusion criteria. Ten environment assessment tools were identified, of which four addressed all seven minor refurbishment domains of lighting, colour and contrast, sound, flooring, furniture, signage and way finding. Only one had undergone reliability and validity testing. There are four tools which may be suitable to use for minor refurbishment of Australian residential aged care facilities. Data on their reliability, validity and quality are limited. © 2017 AJA Inc.

  6. Physics must join with biology in better assessing risk from low-dose irradiation.

    PubMed

    Feinendegen, L E; Neumann, R D

    2005-01-01

    This review summarises the complex response of mammalian cells and tissues to low doses of ionising radiation. This thesis encompasses induction of DNA damage, and adaptive protection against both renewed damage and against propagation of damage from the basic level of biological organisation to the clinical expression of detriment. The induction of DNA damage at low radiation doses apparently is proportional to absorbed dose at the physical/chemical level. However, any propagation of such damage to higher levels of biological organisation inherently follows a sigmoid function. Moreover, low-dose-induced inhibition of damage propagation is not linear, but instead follows a dose-effect function typical for adaptive protection, after an initial rapid rise it disappears at doses higher than approximately 0.1-0.2 Gy to cells. The particular biological response duality at low radiation doses precludes the validity of the linear-no-threshold hypothesis in the attempt to relate absorbed dose to cancer. In fact, theory and observation support not only a lower cancer incidence than expected from the linear-no-threshold hypothesis, but also a reduction of spontaneously occurring cancer, a hormetic response, in the healthy individual.

  7. MODELING THE VARIATIONS OF DOSE RATE MEASURED BY RAD DURING THE FIRST MSL MARTIAN YEAR: 2012–2014

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Guo, Jingnan; Wimmer-Schweingruber, Robert F.; Heber, Bernd

    2015-09-01

    The Radiation Assessment Detector (RAD), on board Mars Science Laboratory’s (MSL) rover Curiosity, measures the energy spectra of both energetic charged and neutral particles along with the radiation dose rate at the surface of Mars. With these first-ever measurements on the Martian surface, RAD observed several effects influencing the galactic cosmic-ray (GCR) induced surface radiation dose concurrently: (a) short-term diurnal variations of the Martian atmospheric pressure caused by daily thermal tides, (b) long-term seasonal pressure changes in the Martian atmosphere, and (c) the modulation of the primary GCR flux by the heliospheric magnetic field, which correlates with long-term solar activitymore » and the rotation of the Sun. The RAD surface dose measurements, along with the surface pressure data and the solar modulation factor, are analyzed and fitted to empirical models that quantitatively demonstrate how the long-term influences ((b) and (c)) are related to the measured dose rates. Correspondingly, we can estimate dose rate and dose equivalents under different solar modulations and different atmospheric conditions, thus allowing empirical predictions of the Martian surface radiation environment.« less

  8. Fast method for in-flight estimation of total dose from protons and electrons using RADE Minstrument on JUICE

    NASA Astrophysics Data System (ADS)

    Hajdas, Wojtek; Mrigakshi, Alankrita; Xiao, Hualin

    2017-04-01

    The primary concern of the ESA JUICE mission to Jupiter is the harsh particle radiation environment. Ionizing particles introduce radiation damage by total dose effects, displacement damages or single events effects. Therefore, both the total ionizing dose and the displacement damage equivalent fluence must be assessed to alert spacecraft and its payload as well as to quantify radiation levels for the entire mission lifetime. We present a concept and implementations steps for simplified method used to compute in flight a dose rate and total dose caused by protons. We also provide refinement of the method previously developed for electrons. The dose rates values are given for predefined active volumes located behind layers of materials with known thickness. Both methods are based on the electron and proton flux measurements provided by the Electron and Proton Detectors inside the Radiation Hard Electron Monitor (RADEM) located on-board of JUICE. The trade-off between method accuracy and programming limitations for in-flight computations are discussed. More comprehensive and precise dose rate computations based on detailed analysis of all stack detectors will be made during off-line data processing. It will utilize full spectral unfolding from all RADEM detector subsystems.

  9. Effects of Low-Dose and Very Low-Dose Ketamine among Patients with Major Depression: a Systematic Review and Meta-Analysis.

    PubMed

    Xu, Ying; Hackett, Maree; Carter, Gregory; Loo, Colleen; Gálvez, Verònica; Glozier, Nick; Glue, Paul; Lapidus, Kyle; McGirr, Alexander; Somogyi, Andrew A; Mitchell, Philip B; Rodgers, Anthony

    2016-04-01

    Several recent trials indicate low-dose ketamine produces rapid antidepressant effects. However, uncertainty remains in several areas: dose response, consistency across patient groups, effects on suicidality, and possible biases arising from crossover trials. A systematic search was conducted for relevant randomized trials in Medline, Embase, and PsycINFO databases up to August 2014. The primary endpoints were change in depression scale scores at days 1, 3 and 7, remission, response, suicidality, safety, and tolerability. Data were independently abstracted by 2 reviewers. Where possible, unpublished data were obtained on treatment effects in the first period of crossover trials. Nine trials were identified, including 201 patients (52% female, mean age 46 years). Six trials assessed low-dose ketamine (0.5 mg/kg i.v.) and 3 tested very low-dose ketamine (one trial assessed 50 mg intra-nasal spray, another assessed 0.1-0.4 mg/kg i.v., and another assessed 0.1-0.5 mg/kg i.v., intramuscular, or s.c.). At day 3, the reduction in depression severity score was less marked in the very low-dose trials (P homogeneity <.05) and among bipolar patients. In analyses excluding the second period of crossover trials, response rates at day 7 were increased with ketamine (relative risk 3.4, 95% CI 1.6-7.1, P=.001), as were remission rates (relative risk 2.6, CI 1.2-5.7, P=.02). The absolute benefits were large, with day 7 remission rates of 24% vs 6% (P=.02). Seven trials provided unpublished data on suicidality item scores, which were reduced on days 1 and 3 (both P<.01) but not day 7. Low-dose ketamine appears more effective than very low dose. There is substantial heterogeneity in clinical response, with remission among one-fifth of patients at 1 week but most others having benefits that are less durable. Larger, longer term parallel group trials are needed to determine if efficacy can be extended and to further assess safety. © The Author 2015. Published by Oxford University

  10. Effects of Low-Dose and Very Low-Dose Ketamine among Patients with Major Depression: a Systematic Review and Meta-Analysis

    PubMed Central

    Xu, Ying; Hackett, Maree; Carter, Gregory; Gálvez, Verònica; Glozier, Nick; Glue, Paul; Lapidus, Kyle; McGirr, Alexander; Somogyi, Andrew A.; Mitchell, Philip B.; Rodgers, Anthony

    2016-01-01

    Background: Several recent trials indicate low-dose ketamine produces rapid antidepressant effects. However, uncertainty remains in several areas: dose response, consistency across patient groups, effects on suicidality, and possible biases arising from crossover trials. Methods: A systematic search was conducted for relevant randomized trials in Medline, Embase, and PsycINFO databases up to August 2014. The primary endpoints were change in depression scale scores at days 1, 3 and 7, remission, response, suicidality, safety, and tolerability. Data were independently abstracted by 2 reviewers. Where possible, unpublished data were obtained on treatment effects in the first period of crossover trials. Results: Nine trials were identified, including 201 patients (52% female, mean age 46 years). Six trials assessed low-dose ketamine (0.5mg/kg i.v.) and 3 tested very low-dose ketamine (one trial assessed 50mg intra-nasal spray, another assessed 0.1–0.4mg/kg i.v., and another assessed 0.1–0.5mg/kg i.v., intramuscular, or s.c.). At day 3, the reduction in depression severity score was less marked in the very low-dose trials (P homogeneity <.05) and among bipolar patients. In analyses excluding the second period of crossover trials, response rates at day 7 were increased with ketamine (relative risk 3.4, 95% CI 1.6–7.1, P=.001), as were remission rates (relative risk 2.6, CI 1.2–5.7, P=.02). The absolute benefits were large, with day 7 remission rates of 24% vs 6% (P=.02). Seven trials provided unpublished data on suicidality item scores, which were reduced on days 1 and 3 (both P<.01) but not day 7. Conclusion: Low-dose ketamine appears more effective than very low dose. There is substantial heterogeneity in clinical response, with remission among one-fifth of patients at 1 week but most others having benefits that are less durable. Larger, longer term parallel group trials are needed to determine if efficacy can be extended and to further assess safety. PMID

  11. 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.

  12. Dose distribution for dental cone beam CT and its implication for defining a dose index

    PubMed Central

    Pauwels, R; Theodorakou, C; Walker, A; Bosmans, H; Jacobs, R; Horner, K; Bogaerts, R

    2012-01-01

    Objectives To characterize the dose distribution for a range of cone beam CT (CBCT) units, investigating different field of view sizes, central and off-axis geometries, full or partial rotations of the X-ray tube and different clinically applied beam qualities. The implications of the dose distributions on the definition and practicality of a CBCT dose index were assessed. Methods Dose measurements on CBCT devices were performed by scanning cylindrical head-size water and polymethyl methacrylate phantoms, using thermoluminescent dosemeters, a small-volume ion chamber and radiochromic films. Results It was found that the dose distribution can be asymmetrical for dental CBCT exposures throughout a homogeneous phantom, owing to an asymmetrical positioning of the isocentre and/or partial rotation of the X-ray source. Furthermore, the scatter tail along the z-axis was found to have a distinct shape, generally resulting in a strong drop (90%) in absorbed dose outside the primary beam. Conclusions There is no optimal dose index available owing to the complicated exposure geometry of CBCT and the practical aspects of quality control measurements. Practical validation of different possible dose indices is needed, as well as the definition of conversion factors to patient dose. PMID:22752320

  13. [Criteria for assessing severely hot environments: from the WBGT index to the PHS (predicted heat strain) model].

    PubMed

    d'Ambrosio, Francesca Romana; Palella, B I; Riccio, G; Alfano, G

    2004-01-01

    The present study deals with the main methods for assessment of hot environments: i.e., WBGT, SWreq and PHS. It is stressed how the WBGT index, which is strictly empirical, although a very practical tool for the assessment of the hot environments, can only be used for a rough evaluation of heat stress, and especially for a not very high metabolic rate (M<175 W/m2). On the contrary, the SWreq method, which is based on both subject-environment heat exchange and the effect of clothing, allows a better assessment of the work situation with a general reduction of the exposure limits with respect to WBGT, especially in non-uniform environments (ta not equal to tr). However, it should be noted that application of SWreq is required by the ISO standard 7243 when the WBGT limit values are exceeded. In this study interest was extensively focused on the "Predicted Heat Strain" method, highlighting via a special software the differences in heat stress assessment related to this new approach, which will be adopted by the ISO in the next revision of standard 7933. The PHS method, unlike SWreq, allows the prediction of the time-response of the main physiological variables of interest (i.e., skin temperature, core temperature and sweat rate). Moreover thanks to better modelling of heat exchanges, the PHS method allows account to be taken of both movement and clothing effects, resulting in even more reduced exposure.

  14. A comparison of independently conducted dose assessments to determine compliance and resettlement options for the people of Rongelap Atoll.

    PubMed

    Simon, S L; Robison, W L; Thorne, M C; Toburen, L H; Franke, B; Baverstock, K F; Pettingill, H J

    1997-07-01

    Rongelap Island was the home of Marshallese people numbering less than 120 in 1954; 67 were on the island and severely exposed to radioactive fallout from an atomic weapons test in March of that year. Those resident on Rongelap were evacuated 50 h after the test, returned 3 y later, then voluntarily left their home island in 1985 due to their ongoing fear of radiation exposure from residual radioactive contamination. Following international negotiations in 1991, a Memorandum of Understanding (MOU) was signed in early 1992 between the Republic of the Marshall Islands Government, the Rongelap Atoll Local Government, the U.S. Department of Energy, and the U.S. Department of the Interior. In this MOU it was agreed that the Republic of the Marshall Islands, with the aid of the U.S. Department of Energy, would carry out independent dose assessments for the purpose of assisting and advising the Rongelap community on radiological issues related to a safe resettlement of Rongelap. The MOU enacted two action levels which were agreed to be used to establish whether mitigation should be considered as a condition for resettlement of Rongelap Island: (1) no individual should receive an annual dose in the future of 1 mSv or more, above that from natural background radiation, assuming that his/her diet consists of only locally produced foods, and (2) the total surface soil concentration of plutonium and other transuranic elements must be less than 629 Bq kg(-1) (averaged over the top 5 cm). Environmental radiological data and dietary information were collected over two years (1992-1993) for the purpose of predicting future potential doses to Rongelapese who might resettle. In 1994, four independent assessments were reported, including one from each of the following entities: Marshall Islands Nationwide Radiological Study; Lawrence Livermore National Laboratory; an independent advisor from the United Kingdom (MCT); and a committee of the National Research Council. All four

  15. Radiation Environment Effects on Spacecraft

    NASA Technical Reports Server (NTRS)

    Ladbury, Ray.

    2017-01-01

    Space poses a variety of radiation hazards. These hazards pose different risks for different missions depending on the mission environment, duration and requirements. This presentation presents a brief look at several radiation related hazards, including destructive and nondestructive Single-Event Effect, Total Ionizing Dose, Displacement Damage and Spacecraft Charging. The temporal and spatial characteristics for the environments of concern for each are considered.

  16. Effects of high-dose fenfluramine treatment on monoamine uptake sites in rat brain: Assessment using quantitative autoradiography

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Appel, N.M.; Mitchell, W.M.; Contrera, J.F.

    1990-01-01

    Fenfluramine is an amphetamine derivative that in humans is used primarily as an anorectic agent in the treatment of obesity. In rats, subchronic high-dose d,l-fenfluramine treatment (24 mg/kg subcutaneously, twice daily for 4 days) causes long-lasting decreases in brain serotonin (5HT), its metabolite 5-hydroxyindoleacetic acid, and high-affinity 5HT uptake sites. Moreover, this high-dose treatment regimen causes both selective long-lasting decreases in fine-caliber 5HT-immunoreactive axons and appearance of other 5HT-immunoreactive axons with morphology characteristic of degenerating axons. Determination of the potential neurotoxic effects of fenfluramine treatment using immunohistochemistry is limited from the perspectives that staining is difficult to quantify and thatmore » it relies on presence of the antigen (in this case 5HT), and the 5HT-depleting effects of fenfluramine are well known. In the present study, we used quantitative in vitro autoradiography to assess, in detail, the density and regional distribution of (3H)paroxetine-labeled 5HT and (3H)mazindol-labeled catecholamine uptake sites in response to the high-dose fenfluramine treatment described above. Because monoamine uptake sites are concentrated on monoamine-containing nerve terminals, decreases in uptake site density would provide a quantitative assessment of potential neurotoxicity resulting from this fenfluramine treatment regimen. Marked decreases in densities of (3H)paroxetine-labeled 5HT uptake sites occurred in brain regions in which fenfluramine treatment decreased the density of 5HT-like immunostaining when compared to saline-treated control rats. These included cerebral cortex, caudate putamen, hippocampus, thalamus, and medial hypothalamus.« less

  17. Assessing alcohol intake & its dose-dependent effects on liver enzymes by 24-h recall and questionnaire using NHANES 2001-2010 data

    DOE PAGES

    Agarwal, Sanjiv; Fulgoni, III, Victor L.; Lieberman, Harris R.

    2016-06-22

    Alcohol is a significant component of the diet with dose-dependent risks and benefits. High doses of alcohol damage the liver and early symptoms of liver disease include changes in routinely assessed liver enzymes. Less is known regarding the mechanisms responsible for the benefits of moderate alcohol consumption, including their effects on the liver. The objectives of this study were to examine alcohol’s dose-dependent effects on markers of liver function (alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyl transferase (GGT), and bilirubin), as well as to compare the different methods of assessing alcohol intake using NHANES 2001–2010 adultmore » data (N =24,807). Three methods were used to estimate alcohol intake from all volunteers: 24-h recall; the National Cancer Institute (NCI) method of usual intake; and a specific alcohol intake questionnaire. Mean alcohol intake by 24-h recall, NCI method and questionnaire was 41.0 ± 0.8 g/d, 10.9 ± 0.2 g/d and 11.0 ± 0.2 g/d, respectively. Alcohol consumers had significantly lower levels of ALP and higher levels of AST, GGT and bilirubin compared to non-consumers (P < 0.01) and activities of ALT, AST, and GGT increased and of ALP decreased as alcohol intake increased, regardless of intake assessment method used. The most sensitive measure of alcohol consumption was GGT. Since alcohol had a graded linear effect on several liver enzymes, including at low and moderate doses, benefits as well as risks of alcohol intake may be related to liver function. In conclusion, since the NCI method and alcohol questionnaire yielded very similar alcohol intake estimates, this study cross-validated these methods and demonstrated the robustness of the NCI method for estimating intake of irregularly consumed foods.« less

  18. Assessing alcohol intake & its dose-dependent effects on liver enzymes by 24-h recall and questionnaire using NHANES 2001-2010 data

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Agarwal, Sanjiv; Fulgoni, III, Victor L.; Lieberman, Harris R.

    Alcohol is a significant component of the diet with dose-dependent risks and benefits. High doses of alcohol damage the liver and early symptoms of liver disease include changes in routinely assessed liver enzymes. Less is known regarding the mechanisms responsible for the benefits of moderate alcohol consumption, including their effects on the liver. The objectives of this study were to examine alcohol’s dose-dependent effects on markers of liver function (alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyl transferase (GGT), and bilirubin), as well as to compare the different methods of assessing alcohol intake using NHANES 2001–2010 adultmore » data (N =24,807). Three methods were used to estimate alcohol intake from all volunteers: 24-h recall; the National Cancer Institute (NCI) method of usual intake; and a specific alcohol intake questionnaire. Mean alcohol intake by 24-h recall, NCI method and questionnaire was 41.0 ± 0.8 g/d, 10.9 ± 0.2 g/d and 11.0 ± 0.2 g/d, respectively. Alcohol consumers had significantly lower levels of ALP and higher levels of AST, GGT and bilirubin compared to non-consumers (P < 0.01) and activities of ALT, AST, and GGT increased and of ALP decreased as alcohol intake increased, regardless of intake assessment method used. The most sensitive measure of alcohol consumption was GGT. Since alcohol had a graded linear effect on several liver enzymes, including at low and moderate doses, benefits as well as risks of alcohol intake may be related to liver function. In conclusion, since the NCI method and alcohol questionnaire yielded very similar alcohol intake estimates, this study cross-validated these methods and demonstrated the robustness of the NCI method for estimating intake of irregularly consumed foods.« less

  19. Modulation of Distinct Asthmatic Phenotypes in Mice by Dose-Dependent Inhalation of Microbial Products

    PubMed Central

    Whitehead, Gregory S.; Thomas, Seddon Y.

    2013-01-01

    Background: Humans with asthma display considerable heterogeneity with regard to T helper (Th) 2–associated eosinophilic and Th17-associated neutrophilic inflammation, but the impact of the environment on these different forms of asthma is poorly understood. Objective: We studied the nature and longevity of asthma-like responses triggered by inhalation of allergen together with environmentally relevant doses of inhaled lipopolysaccharide (LPS). Methods: Ovalbumin (OVA) was instilled into the airways of mice together with a wide range of LPS doses. Following a single OVA challenge, or multiple challenges, animals were assessed for pulmonary cytokine production, airway inflammation, and airway hyperresponsiveness (AHR). Results: Mice instilled with OVA together with very low doses (≤ 10–3 μg) of LPS displayed modest amounts of Th2 cytokines, with associated airway eosinophilia and AHR after a single challenge, and these responses were sustained after multiple OVA challenges. When the higher but still environmentally relevant dose of 10–1 μg LPS was used, mice initially displayed similar Th2 responses, as well as Th17-associated neutrophilia. After multiple OVA challenges, however, the 10–1 μg LPS animals also accumulated large numbers of allergen-specific T regulatory (Treg) cells with high levels of inducible co-stimulatory molecule (ICOS). As a result, asthma-like features in these mice were shorter-lived than in mice sensitized using lower doses of LPS. Conclusions: The nature and longevity of Th2, Th17, and Treg immune responses to inhaled allergen are dependent on the quantity of LPS inhaled at the time of allergic sensitization. These findings might account in part for the heterogeneity of inflammatory infiltrates seen in lungs of asthmatics. Citation: Whitehead GS, Thomas SY, Cook DN. 2014. Modulation of distinct asthmatic phenotypes in mice by dose-dependent inhalation of microbial products. Environ Health Perspect 122:34–42;

  20. Depth dose distribution study within a phantom torso after irradiation with a simulated Solar Particle Event at NSRL

    NASA Astrophysics Data System (ADS)

    Berger, Thomas; Matthiä, Daniel; Koerner, Christine; George, Kerry; Rhone, Jordan; Cucinotta, Francis A.; Reitz, Guenther

    The adequate knowledge of the radiation environment and the doses incurred during a space mission is essential for estimating an astronaut's health risk. The space radiation environment is complex and variable, and exposures inside the spacecraft and the astronaut's body are com-pounded by the interactions of the primary particles with the atoms of the structural materials and with the body itself. Astronauts' radiation exposures are measured by means of personal dosimetry, but there remains substantial uncertainty associated with the computational extrap-olation of skin dose to organ dose, which can lead to over-or under-estimation of the health risk. Comparisons of models to data showed that the astronaut's Effective dose (E) can be pre-dicted to within about a +10In the research experiment "Depth dose distribution study within a phantom torso" at the NASA Space Radiation Laboratory (NSRL) at BNL, Brookhaven, USA the large 1972 SPE spectrum was simulated using seven different proton energies from 50 up to 450 MeV. A phantom torso constructed of natural bones and realistic distributions of human tissue equivalent materials, which is comparable to the torso of the MATROSHKA phantom currently on the ISS, was equipped with a comprehensive set of thermoluminescence detectors and human cells. The detectors are applied to assess the depth dose distribution and radiation transport codes (e.g. GEANT4) are used to assess the radiation field and interactions of the radiation field with the phantom torso. Lymphocyte cells are strategically embedded at selected locations at the skin and internal organs and are processed after irradiation to assess the effects of shielding on the yield of chromosome damage. The first focus of the pre-sented experiment is to correlate biological results with physical dosimetry measurements in the phantom torso. Further on the results of the passive dosimetry using the anthropomorphic phantoms represent the best tool to generate reliable to