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Sample records for dose statistics resulting

  1. Estimation of thyroid radiation doses for the hanford thyroid disease study: results and implications for statistical power of the epidemiological analyses.

    PubMed

    Kopecky, Kenneth J; Davis, Scott; Hamilton, Thomas E; Saporito, Mark S; Onstad, Lynn E

    2004-07-01

    Residents of eastern Washington, northeastern Oregon, and western Idaho were exposed to I released into the atmosphere from operations at the Hanford Nuclear Site from 1944 through 1972, especially in the late 1940's and early 1950's. This paper describes the estimated doses to the thyroid glands of the 3,440 evaluable participants in the Hanford Thyroid Disease Study, which investigated whether thyroid morbidity was increased in people exposed to radioactive iodine from Hanford during 1944-1957. The participants were born during 1940-1946 to mothers living in Benton, Franklin, Walla Walla, Adams, Okanogan, Ferry, or Stevens Counties in Washington State. Whenever possible someone with direct knowledge of the participant's early life (preferably the participant's mother) was interviewed about the participant's individual dose-determining characteristics (residence history, sources and quantities of food, milk, and milk products consumed, production and processing techniques for home-grown food and milk products). Default information was used if no interview respondent was available. Thyroid doses were estimated using the computer program Calculation of Individual Doses from Environmental Radionuclides (CIDER) developed by the Hanford Environmental Dose Reconstruction Project. CIDER provided 100 sets of doses to represent uncertainty of the estimates. These sets were not generated independently for each participant, but reflected the effects of uncertainties in characteristics shared by participants. Estimated doses (medians of each participant's 100 realizations) ranged from 0.0029 mGy to 2823 mGy, with mean and median of 174 and 97 mGy, respectively. The distribution of estimated doses provided the Hanford Thyroid Disease Study with sufficient statistical power to test for dose-response relationships between thyroid outcomes and exposure to Hanford's I.

  2. [Results of statistical analysis of the dynamics of ionizing radiation dose fields in the service module of the International Space Station in 2000-2012].

    PubMed

    Mitrikas, V G

    2014-01-01

    The on-going 24th solar cycle (SC) is distinguished from the previous ones by low activity. On the contrary, levels of proton fluxes from galactic cosmic rays (GCR) are high, which increases the proton flow striking the Earth's radiation belts (ERB). Therefore, at present the absorbed dose from ERB protons should be calculated with consideration of the tangible increase of protons intensity built into the model descriptions based on experimental measurements during the minimum between cycles 19 and 20, and the cycle 21 maximum. The absorbed dose from GCR and ERB protons copies galactic protons dynamics, while the ERB electrons dose copies SC dynamics. The major factors that determine the absorbed dose value are SC phase, ISS orbital altitude and shielding of the dosimeter readings of which are used in analysis. The paper presents the results of dynamic analysis of absorbed doses measured by a variety of dosimeters, namely, R-16 (2 ionization chambers), DB8-1, DB8-2, DB8-3, DB8-4 as a function of ISS orbit altitude and SC phase. The existence of annual variation in the absorbed dose dynamics has been confirmed; several additional variations with the periods of 17 and 52 months have been detected. Modulation of absorbed dose variations by the SC and GCR amplitudes has been demonstrated.

  3. Ideas for Effective Communication of Statistical Results

    DOE PAGES

    Anderson-Cook, Christine M.

    2015-03-01

    Effective presentation of statistical results to those with less statistical training, including managers and decision-makers requires planning, anticipation and thoughtful delivery. Here are several recommendations for effectively presenting statistical results.

  4. Ideas for Effective Communication of Statistical Results

    SciTech Connect

    Anderson-Cook, Christine M.

    2015-03-01

    Effective presentation of statistical results to those with less statistical training, including managers and decision-makers requires planning, anticipation and thoughtful delivery. Here are several recommendations for effectively presenting statistical results.

  5. Reporting Statistical Results in Medical Journals.

    PubMed

    Arifin, Wan Nor; Sarimah, Abdullah; Norsa'adah, Bachok; Najib Majdi, Yaacob; Siti-Azrin, Ab Hamid; Kamarul Imran, Musa; Aniza, Abd Aziz; Naing, Lin

    2016-09-01

    Statistical editors of the Malaysian Journal of Medical Sciences (MJMS) must go through many submitted manuscripts, focusing on the statistical aspect of the manuscripts. However, the editors notice myriad styles of reporting the statistical results, which are not standardised among the authors. This could be due to the lack of clear written instructions on reporting statistics in the guidelines for authors. The aim of this editorial is to briefly outline reporting methods for several important and common statistical results. It will also address a number of common mistakes made by the authors. The editorial will serve as a guideline for authors aiming to publish in the MJMS as well as in other medical journals.

  6. Statistical literacy and sample survey results

    NASA Astrophysics Data System (ADS)

    McAlevey, Lynn; Sullivan, Charles

    2010-10-01

    Sample surveys are widely used in the social sciences and business. The news media almost daily quote from them, yet they are widely misused. Using students with prior managerial experience embarking on an MBA course, we show that common sample survey results are misunderstood even by those managers who have previously done a statistics course. In general, they fare no better than managers who have never studied statistics. There are implications for teaching, especially in business schools, as well as for consulting.

  7. Statistical Literacy and Sample Survey Results

    ERIC Educational Resources Information Center

    McAlevey, Lynn; Sullivan, Charles

    2010-01-01

    Sample surveys are widely used in the social sciences and business. The news media almost daily quote from them, yet they are widely misused. Using students with prior managerial experience embarking on an MBA course, we show that common sample survey results are misunderstood even by those managers who have previously done a statistics course. In…

  8. Statistical Literacy and Sample Survey Results

    ERIC Educational Resources Information Center

    McAlevey, Lynn; Sullivan, Charles

    2010-01-01

    Sample surveys are widely used in the social sciences and business. The news media almost daily quote from them, yet they are widely misused. Using students with prior managerial experience embarking on an MBA course, we show that common sample survey results are misunderstood even by those managers who have previously done a statistics course. In…

  9. Statistical characterization of radiation doses from external exposures and relevant contributors in Fukushima prefecture.

    PubMed

    Takahara, Shogo; Abe, Tatsuya; Iijima, Masashi; Shimada, Kazumasa; Shiratori, Yoshitake

    2014-10-01

    In areas contaminated by radioactive materials, well designed dose assessment is necessary in order to protect people from radiation exposure and manage the exposure situation appropriately. Probabilistic dose assessment is a useful method for providing a more complete characterization of information on dose distributions in the population and requires statistically characterized data on pathway-relevant contributors. The objective of this paper is to determine statistical features of contributors to external exposures, as well as to identify causes of variabilities of individual doses to the populations living in areas contaminated by the Fukushima Daiichi Nuclear Power Plant accident. To achieve these objectives, measurements of individual doses and ambient dose rates, as well as surveys of behavioral patterns, were performed between February and April 2012. These were made with the cooperation of indoor workers, outdoor workers, and pensioners living in Fukushima prefecture. On the basis of these results, statistical analyses were performed in order to identify variabilities of contributors. In addition, a multi-regression analysis was done to explore a significant relationship between individual doses and relevant contributors. Results showed that the ambient dose equivalent rate also distributed with lognormal form, and it had variabilities attributable to the spatial distribution of deposited radionuclides. The distribution form of time spent outdoors depends on the characteristics of occupation, and the distributions for indoor workers and outdoor workers were lognormal and normal, respectively. Results of a multiple-regression analysis suggested that such variabilities of contributors give rise to significant differences in individual doses among the populations.

  10. CALUX measurements: statistical inferences for the dose-response curve.

    PubMed

    Elskens, M; Baston, D S; Stumpf, C; Haedrich, J; Keupers, I; Croes, K; Denison, M S; Baeyens, W; Goeyens, L

    2011-09-30

    Chemical Activated LUciferase gene eXpression [CALUX] is a reporter gene mammalian cell bioassay used for detection and semi-quantitative analyses of dioxin-like compounds. CALUX dose-response curves for 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] are typically smooth and sigmoidal when the dose is portrayed on a logarithmic scale. Non-linear regression models are used to calibrate the CALUX response versus TCDD standards and to convert the sample response into Bioanalytical EQuivalents (BEQs). Several complications may arise in terms of statistical inference, specifically and most important is the uncertainty assessment of the predicted BEQ. This paper presents the use of linear calibration functions based on Box-Cox transformations to overcome the issue of uncertainty assessment. Main issues being addressed are (i) confidence and prediction intervals for the CALUX response, (ii) confidence and prediction intervals for the predicted BEQ-value, and (iii) detection/estimation capabilities for the sigmoid and linearized models. Statistical comparisons between different calculation methods involving inverse prediction, effective concentration ratios (ECR(20-50-80)) and slope ratio were achieved with example datasets in order to provide guidance for optimizing BEQ determinations and expand assay performance with the recombinant mouse hepatoma CALUX cell line H1L6.1c3.

  11. The analysis of dose-response curve from bioassays with quantal response: Deterministic or statistical approaches?

    PubMed

    Mougabure-Cueto, G; Sfara, V

    2016-04-25

    Dose-response relations can be obtained from systems at any structural level of biological matter, from the molecular to the organismic level. There are two types of approaches for analyzing dose-response curves: a deterministic approach, based on the law of mass action, and a statistical approach, based on the assumed probabilities distribution of phenotypic characters. Models based on the law of mass action have been proposed to analyze dose-response relations across the entire range of biological systems. The purpose of this paper is to discuss the principles that determine the dose-response relations. Dose-response curves of simple systems are the result of chemical interactions between reacting molecules, and therefore are supported by the law of mass action. In consequence, the shape of these curves is perfectly sustained by physicochemical features. However, dose-response curves of bioassays with quantal response are not explained by the simple collision of molecules but by phenotypic variations among individuals and can be interpreted as individual tolerances. The expression of tolerance is the result of many genetic and environmental factors and thus can be considered a random variable. In consequence, the shape of its associated dose-response curve has no physicochemical bearings; instead, they are originated from random biological variations. Due to the randomness of tolerance there is no reason to use deterministic equations for its analysis; on the contrary, statistical models are the appropriate tools for analyzing these dose-response relations. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. NLO error propagation exercise: statistical results

    SciTech Connect

    Pack, D.J.; Downing, D.J.

    1985-09-01

    Error propagation is the extrapolation and cumulation of uncertainty (variance) above total amounts of special nuclear material, for example, uranium or /sup 235/U, that are present in a defined location at a given time. The uncertainty results from the inevitable inexactness of individual measurements of weight, uranium concentration, /sup 235/U enrichment, etc. The extrapolated and cumulated uncertainty leads directly to quantified limits of error on inventory differences (LEIDs) for such material. The NLO error propagation exercise was planned as a field demonstration of the utilization of statistical error propagation methodology at the Feed Materials Production Center in Fernald, Ohio from April 1 to July 1, 1983 in a single material balance area formed specially for the exercise. Major elements of the error propagation methodology were: variance approximation by Taylor Series expansion; variance cumulation by uncorrelated primary error sources as suggested by Jaech; random effects ANOVA model estimation of variance effects (systematic error); provision for inclusion of process variance in addition to measurement variance; and exclusion of static material. The methodology was applied to material balance area transactions from the indicated time period through a FORTRAN computer code developed specifically for this purpose on the NLO HP-3000 computer. This paper contains a complete description of the error propagation methodology and a full summary of the numerical results of applying the methodlogy in the field demonstration. The error propagation LEIDs did encompass the actual uranium and /sup 235/U inventory differences. Further, one can see that error propagation actually provides guidance for reducing inventory differences and LEIDs in future time periods.

  13. Ultralow dose computed tomography attenuation correction for pediatric PET CT using adaptive statistical iterative reconstruction

    SciTech Connect

    Brady, Samuel L.; Shulkin, Barry L.

    2015-02-15

    Purpose: To develop ultralow dose computed tomography (CT) attenuation correction (CTAC) acquisition protocols for pediatric positron emission tomography CT (PET CT). Methods: A GE Discovery 690 PET CT hybrid scanner was used to investigate the change to quantitative PET and CT measurements when operated at ultralow doses (10–35 mA s). CT quantitation: noise, low-contrast resolution, and CT numbers for 11 tissue substitutes were analyzed in-phantom. CT quantitation was analyzed to a reduction of 90% volume computed tomography dose index (0.39/3.64; mGy) from baseline. To minimize noise infiltration, 100% adaptive statistical iterative reconstruction (ASiR) was used for CT reconstruction. PET images were reconstructed with the lower-dose CTAC iterations and analyzed for: maximum body weight standardized uptake value (SUV{sub bw}) of various diameter targets (range 8–37 mm), background uniformity, and spatial resolution. Radiation dose and CTAC noise magnitude were compared for 140 patient examinations (76 post-ASiR implementation) to determine relative dose reduction and noise control. Results: CT numbers were constant to within 10% from the nondose reduced CTAC image for 90% dose reduction. No change in SUV{sub bw}, background percent uniformity, or spatial resolution for PET images reconstructed with CTAC protocols was found down to 90% dose reduction. Patient population effective dose analysis demonstrated relative CTAC dose reductions between 62% and 86% (3.2/8.3–0.9/6.2). Noise magnitude in dose-reduced patient images increased but was not statistically different from predose-reduced patient images. Conclusions: Using ASiR allowed for aggressive reduction in CT dose with no change in PET reconstructed images while maintaining sufficient image quality for colocalization of hybrid CT anatomy and PET radioisotope uptake.

  14. Dose impact in radiographic lung injury following lung SBRT: Statistical analysis and geometric interpretation

    SciTech Connect

    Yu, Victoria; Kishan, Amar U.; Cao, Minsong; Low, Daniel; Lee, Percy; Ruan, Dan

    2014-03-15

    been demonstrated. Bimodal behavior was observed in the dose distribution of lung injury after SBRT. Novel statistical and geometrical analysis has shown that the systematically quantified low-dose peak at approximately 35 Gy, or 70% prescription dose, is a good indication of a critical dose for injury. The determined critical dose of 35 Gy resembles the critical dose volume limit of 30 Gy for ipsilateral bronchus in RTOG 0618 and results from previous studies. The authors seek to further extend this improved analysis method to a larger cohort to better understand the interpatient variation in radiographic lung injury dose response post-SBRT.

  15. Statistical analysis of nanoparticle dosing in a dynamic cellular system

    NASA Astrophysics Data System (ADS)

    Summers, Huw D.; Rees, Paul; Holton, Mark D.; Rowan Brown, M.; Chappell, Sally C.; Smith, Paul J.; Errington, Rachel J.

    2011-03-01

    The delivery of nanoparticles into cells is important in therapeutic applications and in nanotoxicology. Nanoparticles are generally targeted to receptors on the surfaces of cells and internalized into endosomes by endocytosis, but the kinetics of the process and the way in which cell division redistributes the particles remain unclear. Here we show that the chance of success or failure of nanoparticle uptake and inheritance is random. Statistical analysis of nanoparticle-loaded endosomes indicates that particle capture is described by an over-dispersed Poisson probability distribution that is consistent with heterogeneous adsorption and internalization. Partitioning of nanoparticles in cell division is random and asymmetric, following a binomial distribution with mean probability of 0.52-0.72. These results show that cellular targeting of nanoparticles is inherently imprecise due to the randomness of nature at the molecular scale, and the statistical framework offers a way to predict nanoparticle dosage for therapy and for the study of nanotoxins.

  16. T1 VSAT Fade Compensation Statistical Results

    NASA Technical Reports Server (NTRS)

    Johnson, Sandra K.; Acosta, Roberto; Ugweje, Oke

    2000-01-01

    New satellite communication systems are steadily seeking to use higher frequency bands to accommodate the requirements for additional capacity. At these higher frequencies, propagation impairments that did not significantly affect the signal at lower frequencies begin to have considerable impact. In Ka-band. the next logical commercial frequency band to be used for satellite communication, attenuation of the signal due to rain is a primary concern. An experimental satellite built by NASA, the Advanced Communication Technology Satellite (ACTS). launched in September 1993, is the first U.S. communication satellite operating in the Ka-band. In addition to higher carrier frequencies, a number of other new technologies, including on-board baseband processing. multiple beam antennas, and rain fade detection and compensation techniques, were designed into the ACTS. Verification experiments have been conducted since the launch to characterize the new technologies. The focus of this paper is to characterize the method used by the ACTS TI Very Small Aperture Terminal (TI VSAT) ground stations in detecting the presence of fade in the communication signal and to adaptively compensate for it by the addition of burst rate reduction and forward error correction. Measured data obtained from the ACTS program was used to validate the compensation technique. A software process was developed and demonstrated to statistically characterize the increased availability achieved by the compensation techniques in terms of the bit error rate time enhancement factor. Several improvements to the ACTS technique are discussed and possible implementations for future Ka band system are offered.

  17. Statistical strategies for averaging EC50 from multiple dose-response experiments.

    PubMed

    Jiang, Xiaoqi; Kopp-Schneider, Annette

    2015-11-01

    In most dose-response studies, repeated experiments are conducted to determine the EC50 value for a chemical, requiring averaging EC50 estimates from a series of experiments. Two statistical strategies, the mixed-effect modeling and the meta-analysis approach, can be applied to estimate average behavior of EC50 values over all experiments by considering the variabilities within and among experiments. We investigated these two strategies in two common cases of multiple dose-response experiments in (a) complete and explicit dose-response relationships are observed in all experiments and in (b) only in a subset of experiments. In case (a), the meta-analysis strategy is a simple and robust method to average EC50 estimates. In case (b), all experimental data sets can be first screened using the dose-response screening plot, which allows visualization and comparison of multiple dose-response experimental results. As long as more than three experiments provide information about complete dose-response relationships, the experiments that cover incomplete relationships can be excluded from the meta-analysis strategy of averaging EC50 estimates. If there are only two experiments containing complete dose-response information, the mixed-effects model approach is suggested. We subsequently provided a web application for non-statisticians to implement the proposed meta-analysis strategy of averaging EC50 estimates from multiple dose-response experiments.

  18. Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

    SciTech Connect

    Tao, Yinghua; Chen, Guang-Hong; Hacker, Timothy A.; Raval, Amish N.; Van Lysel, Michael S.; Speidel, Michael A.

    2014-07-15

    Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan was performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937

  19. Low dose dynamic CT myocardial perfusion imaging using a statistical iterative reconstruction method

    PubMed Central

    Tao, Yinghua; Chen, Guang-Hong; Hacker, Timothy A.; Raval, Amish N.; Van Lysel, Michael S.; Speidel, Michael A.

    2014-01-01

    Purpose: Dynamic CT myocardial perfusion imaging has the potential to provide both functional and anatomical information regarding coronary artery stenosis. However, radiation dose can be potentially high due to repeated scanning of the same region. The purpose of this study is to investigate the use of statistical iterative reconstruction to improve parametric maps of myocardial perfusion derived from a low tube current dynamic CT acquisition. Methods: Four pigs underwent high (500 mA) and low (25 mA) dose dynamic CT myocardial perfusion scans with and without coronary occlusion. To delineate the affected myocardial territory, an N-13 ammonia PET perfusion scan was performed for each animal in each occlusion state. Filtered backprojection (FBP) reconstruction was first applied to all CT data sets. Then, a statistical iterative reconstruction (SIR) method was applied to data sets acquired at low dose. Image voxel noise was matched between the low dose SIR and high dose FBP reconstructions. CT perfusion maps were compared among the low dose FBP, low dose SIR and high dose FBP reconstructions. Numerical simulations of a dynamic CT scan at high and low dose (20:1 ratio) were performed to quantitatively evaluate SIR and FBP performance in terms of flow map accuracy, precision, dose efficiency, and spatial resolution. Results: Forin vivo studies, the 500 mA FBP maps gave −88.4%, −96.0%, −76.7%, and −65.8% flow change in the occluded anterior region compared to the open-coronary scans (four animals). The percent changes in the 25 mA SIR maps were in good agreement, measuring −94.7%, −81.6%, −84.0%, and −72.2%. The 25 mA FBP maps gave unreliable flow measurements due to streaks caused by photon starvation (percent changes of +137.4%, +71.0%, −11.8%, and −3.5%). Agreement between 25 mA SIR and 500 mA FBP global flow was −9.7%, 8.8%, −3.1%, and 26.4%. The average variability of flow measurements in a nonoccluded region was 16.3%, 24.1%, and 937

  20. Adaptive dose finding based on t-statistic for dose-response trials.

    PubMed

    Ivanova, Anastasia; Bolognese, James A; Perevozskaya, Inna

    2008-05-10

    The goals of phase II dose-response studies are to prove that the treatment is effective and to choose the dose for further development. Randomized designs with equal allocation to either a high dose and placebo or to each of several doses and placebo are typically used. However, in trials where response is observed relatively quickly, adaptive designs might offer an advantage over equal allocation. We propose an adaptive design for dose-response trials that concentrates the allocation of subjects in one or more areas of interest, for example, near a minimum clinically important effect level, or near some maximal effect level, and also allows for the possibility to stop the trial early if needed. The proposed adaptive design yields higher power to detect a dose-response relationship, higher power in comparison with placebo, and selects the correct dose more frequently compared with a corresponding randomized design with equal allocation to doses.

  1. Fewer doses of HPV vaccine result in immune response similar to three-dose regimen

    Cancer.gov

    NCI scientists report that two doses of a human papillomavirus (HPV) vaccine, trademarked as Cervarix, resulted in similar serum antibody levels against two of the most carcinogenic types of HPV (16 and 18), compared to a standard three dose regimen.

  2. Fewer doses of HPV vaccine result in immune response similar to three-dose regimen

    Cancer.gov

    NCI scientists report that two doses of a human papillomavirus (HPV) vaccine, trademarked as Cervarix, resulted in similar serum antibody levels against two of the most carcinogenic types of HPV (16 and 18), compared to a standard three dose regimen.

  3. Appropriate statistical methods to compare dose responses of methionine sources.

    PubMed

    Kratzer, D D; Littell, R C

    2006-05-01

    Two sources of methionine (Met) activity are frequently used in commercial feed formulation: DL-2-hydroxy-4-(methylthio) butanoic acid (HMTBA), most commonly available as an 88% solution with 12% water; and DL-methionine (DLM, 99% powder). Despite the fact that both compounds have been in commercial use for over 50 yr, controversy and confusion remain with respect to their relative bioefficacy (RBE). This paper presents a review of the use of a nonlinear common plateau asymptotic regression technique (NLCPAR) that has been used to compare the 2 Met sources with particular emphasis on the validity of the basic assumptions of that model. The thesis of this paper is that the controversy is due, at least in part, to the misapplication of this regression technique to estimate the RBE of HMTBA and DLM. The NLCPAR model is a bioassay with the key dependent assumptions that HMTBA is a dilution of DLM, and that each follows dose-response curves of the same form and approach a common plateau. Because both provide Met activity, it may be considered reasonable to accept these assumptions; however, specifically testing them demonstrated that the assumption of a common dose-response is not supported by data. The common plateau assumption was tested with an alternative approach of fitting nonlinear separate plateaus asymptotic regression (NLSPAR) to a set of 13 published broiler studies in which the NLCPAR model had been used to estimate RBE of HMTBA and DLM. The hypothesis of a common plateau was rejected (P < 0.01), meaning that the conclusion that HMTBA had lower bioefficacy than DLM based on the NLCPAR methodology was not valid. An example using published data demonstrated that the NLSPAR model was a significantly better fit than the NLCPAR model, and showed that HMTBA and DLM followed different dose responses. Consequently, there was no single value for RBE for the entire dose range; rather, the RBE of the 2 compounds varied with use level. The evidence presented here

  4. Statistical distributions of ultra-low dose CT sinograms and their fundamental limits

    NASA Astrophysics Data System (ADS)

    Lee, Tzu-Cheng; Zhang, Ruoqiao; Alessio, Adam M.; Fu, Lin; De Man, Bruno; Kinahan, Paul E.

    2017-03-01

    Low dose CT imaging is typically constrained to be diagnostic. However, there are applications for even lowerdose CT imaging, including image registration across multi-frame CT images and attenuation correction for PET/CT imaging. We define this as the ultra-low-dose (ULD) CT regime where the exposure level is a factor of 10 lower than current low-dose CT technique levels. In the ULD regime it is possible to use statistically-principled image reconstruction methods that make full use of the raw data information. Since most statistical based iterative reconstruction methods are based on the assumption of that post-log noise distribution is close to Poisson or Gaussian, our goal is to understand the statistical distribution of ULD CT data with different non-positivity correction methods, and to understand when iterative reconstruction methods may be effective in producing images that are useful for image registration or attenuation correction in PET/CT imaging. We first used phantom measurement and calibrated simulation to reveal how the noise distribution deviate from normal assumption under the ULD CT flux environment. In summary, our results indicate that there are three general regimes: (1) Diagnostic CT, where post-log data are well modeled by normal distribution. (2) Lowdose CT, where normal distribution remains a reasonable approximation and statistically-principled (post-log) methods that assume a normal distribution have an advantage. (3) An ULD regime that is photon-starved and the quadratic approximation is no longer effective. For instance, a total integral density of 4.8 (ideal pi for 24 cm of water) for 120kVp, 0.5mAs of radiation source is the maximum pi value where a definitive maximum likelihood value could be found. This leads to fundamental limits in the estimation of ULD CT data when using a standard data processing stream

  5. Statistical analysis of dose heterogeneity in circulating blood: Implications for sequential methods of total body irradiation

    SciTech Connect

    Molloy, Janelle A.

    2010-11-15

    Purpose: Improvements in delivery techniques for total body irradiation (TBI) using Tomotherapy and intensity modulated radiation therapy have been proven feasible. Despite the promise of improved dose conformality, the application of these ''sequential'' techniques has been hampered by concerns over dose heterogeneity to circulating blood. The present study was conducted to provide quantitative evidence regarding the potential clinical impact of this heterogeneity. Methods: Blood perfusion was modeled analytically as possessing linear, sinusoidal motion in the craniocaudal dimension. The average perfusion period for human circulation was estimated to be approximately 78 s. Sequential treatment delivery was modeled as a Gaussian-shaped dose cloud with a 10 cm length that traversed a 183 cm patient length at a uniform speed. Total dose to circulating blood voxels was calculated via numerical integration and normalized to 2 Gy per fraction. Dose statistics and equivalent uniform dose (EUD) were calculated for relevant treatment times, radiobiological parameters, blood perfusion rates, and fractionation schemes. The model was then refined to account for random dispersion superimposed onto the underlying periodic blood flow. Finally, a fully stochastic model was developed using binomial and trinomial probability distributions. These models allowed for the analysis of nonlinear sequential treatment modalities and treatment designs that incorporate deliberate organ sparing. Results: The dose received by individual blood voxels exhibited asymmetric behavior that depended on the coherence among the blood velocity, circulation phase, and the spatiotemporal characteristics of the irradiation beam. Heterogeneity increased with the perfusion period and decreased with the treatment time. Notwithstanding, heterogeneity was less than {+-}10% for perfusion periods less than 150 s. The EUD was compromised for radiosensitive cells, long perfusion periods, and short treatment times

  6. Statistical variability and confidence intervals for planar dose QA pass rates

    SciTech Connect

    Bailey, Daniel W.; Nelms, Benjamin E.; Attwood, Kristopher; Kumaraswamy, Lalith; Podgorsak, Matthew B.

    2011-11-15

    techniques. Results: For the prostate and head/neck cases studied, the pass rates obtained with gamma analysis of high density dose planes were 2%-5% higher than respective %/DTA composite analysis on average (ranging as high as 11%), depending on tolerances and normalization. Meanwhile, the pass rates obtained via local normalization were 2%-12% lower than with global maximum normalization on average (ranging as high as 27%), depending on tolerances and calculation method. Repositioning of simulated low-density sampled grids leads to a distribution of possible pass rates for each measured/calculated dose plane pair. These distributions can be predicted using a binomial distribution in order to establish confidence intervals that depend largely on the sampling density and the observed pass rate (i.e., the degree of difference between measured and calculated dose). These results can be extended to apply to 3D arrays of detectors, as well. Conclusions: Dose plane QA analysis can be greatly affected by choice of calculation metric and user-defined parameters, and so all pass rates should be reported with a complete description of calculation method. Pass rates for low-density arrays are subject to statistical uncertainty (vs. the high-density pass rate), but these sampling errors can be modeled using statistical confidence intervals derived from the sampled pass rate and detector density. Thus, pass rates for low-density array measurements should be accompanied by a confidence interval indicating the uncertainty of each pass rate.

  7. BENCHMARKING UPGRADED HOTSPOT DOSE CALCULATIONS AGAINST MACCS2 RESULTS

    SciTech Connect

    Brotherton, Kevin

    2009-04-30

    The radiological consequence of interest for a documented safety analysis (DSA) is the centerline Total Effective Dose Equivalent (TEDE) incurred by the Maximally Exposed Offsite Individual (MOI) evaluated at the 95th percentile consequence level. An upgraded version of HotSpot (Version 2.07) has been developed with the capabilities to read site meteorological data and perform the necessary statistical calculations to determine the 95th percentile consequence result. These capabilities should allow HotSpot to join MACCS2 (Version 1.13.1) and GENII (Version 1.485) as radiological consequence toolbox codes in the Department of Energy (DOE) Safety Software Central Registry. Using the same meteorological data file, scenarios involving a one curie release of {sup 239}Pu were modeled in both HotSpot and MACCS2. Several sets of release conditions were modeled, and the results compared. In each case, input parameter specifications for each code were chosen to match one another as much as the codes would allow. The results from the two codes are in excellent agreement. Slight differences observed in results are explained by algorithm differences.

  8. Modern Statistical Graphs that Provide Insight in Research Results

    USDA-ARS?s Scientific Manuscript database

    Modern statistical graphics offer insight in assessing the results of many common statistical analyses. These ideas, however, are rarely employed in agronomic research articles. This work presents several commonly used graphs, offers one or more alternatives for each, and provides the reasons for pr...

  9. Reviewer Bias for Statistically Significant Results: A Reexamination.

    ERIC Educational Resources Information Center

    Fagley, N. S.; McKinney, I. Jean

    1983-01-01

    Reexamines the article by Atkinson, Furlong, and Wampold (1982) and questions their conclusion that reviewers were biased toward statistically significant results. A statistical power analysis shows the power of their bogus study was low. Low power in a study reporting nonsignificant findings is a valid reason for recommending not to publish.…

  10. The estimation of the measurement results with using statistical methods

    NASA Astrophysics Data System (ADS)

    Velychko, O.; Gordiyenko, T.

    2015-02-01

    The row of international standards and guides describe various statistical methods that apply for a management, control and improvement of processes with the purpose of realization of analysis of the technical measurement results. The analysis of international standards and guides on statistical methods estimation of the measurement results recommendations for those applications in laboratories is described. For realization of analysis of standards and guides the cause-and-effect Ishikawa diagrams concerting to application of statistical methods for estimation of the measurement results are constructed.

  11. Indonesia: statistical sampling technique in validation of radiation sterilisation dose of biological tissue.

    PubMed

    Hilmy, N; Basril, A; Febrida, A

    2003-01-01

    The aim of the work is to find the best solution for statistical sampling technique in validation of radiation sterilization dose (RSD) for biological tissues, according to ISO standard. As a model for sampling are biological tissues retrieved from one cadaver donor which consist of frozen bone grafts (18 packets), lyophilized allografts (68 packets) and demineralized bone powder grafts (40 packets). The size and type of products vary from long bones, cancellous chips to bone powders, tendons and facia lata, that make the number of bioburden per product could not be treated equally. Frozen samples could not be considered as the same production batch with lyophilized samples, because of different processing and irradiation temperature. The minimum number of uniformed samples needed for validation per production batch size, according to ISO 13409, is from 20 to 79 and 20 of them will be used for the test sample size, i.e. 10 for bio-burden determination and the remaining 10 for verification dose. Based on the number of uniformed grafts, statistical sampling can be carried out on lyophilized and demineralized bone grafts, but not on frozen bone grafts. Bioburden determinations were carried out and validated according to ISO 11737-1. Results of average bioburden determination (cfu/per packet), using sample item portion (SIP) = 1, are 5 cfu/packet for lyophilized bone grafts and 4 cfu/packet for demineralized bone powder grafts. Verification doses obtained were 2.40 kGy for lyophilized grafts and 2.24 kGy for demineralized bone powder grafts. The results of verification dose were accepted and the RSD of 25 kGy is substantiated It can be concluded that a statistical sampling technique can be applied if all the grafts produced in the same process such as lyophilized, demineralized as well as frozen are assumed to be in one production batch regardless of sample uniformity such as size, type and weight; for this ISO 13409 can be applied for the validation of RSD.

  12. Statistical image reconstruction for low-dose CT using nonlocal means-based regularization.

    PubMed

    Zhang, Hao; Ma, Jianhua; Wang, Jing; Liu, Yan; Lu, Hongbing; Liang, Zhengrong

    2014-09-01

    Low-dose computed tomography (CT) imaging without sacrifice of clinical tasks is desirable due to the growing concerns about excessive radiation exposure to the patients. One common strategy to achieve low-dose CT imaging is to lower the milliampere-second (mAs) setting in data scanning protocol. However, the reconstructed CT images by the conventional filtered back-projection (FBP) method from the low-mAs acquisitions may be severely degraded due to the excessive noise. Statistical image reconstruction (SIR) methods have shown potentials to significantly improve the reconstructed image quality from the low-mAs acquisitions, wherein the regularization plays a critical role and an established family of regularizations is based on the Markov random field (MRF) model. Inspired by the success of nonlocal means (NLM) in image processing applications, in this work, we propose to explore the NLM-based regularization for SIR to reconstruct low-dose CT images from low-mAs acquisitions. Experimental results with both digital and physical phantoms consistently demonstrated that SIR with the NLM-based regularization can achieve more gains than SIR with the well-known Gaussian MRF regularization or the generalized Gaussian MRF regularization and the conventional FBP method, in terms of image noise reduction and resolution preservation.

  13. Statistical image reconstruction for low-dose CT using nonlocal means-based regularization

    PubMed Central

    Zhang, Hao; Ma, Jianhua; Wang, Jing; Liu, Yan; Lu, Hongbing

    2014-01-01

    Low-dose computed tomography (CT) imaging without sacrifice of clinical tasks is desirable due to the growing concerns about excessive radiation exposure to the patients. One common strategy to achieve low-dose CT imaging is to lower the milliampere-second (mAs) setting in data scanning protocol. However, the reconstructed CT images by the conventional filtered back-projection (FBP) method from the low-mAs acquisitions may be severely degraded due to the excessive noise. Statistical image reconstruction (SIR) methods have shown potentials to significantly improve the reconstructed image quality from the low-mAs acquisitions, wherein the regularization plays a critical role and an established family of regularizations is based on the Markov random field (MRF) model. Inspired by the success of nonlocal means (NLM) in image processing applications, in this work, we propose to explore the NLM-based regularization for SIR to reconstruct low-dose CT images from low-mAs acquisitions. Experimental results with both digital and physical phantoms consistently demonstrated that SIR with the NLM-based regularization can achieve more gains than SIR with the well-known Gaussian MRF regularization or the generalized Gaussian MRF regularization and the conventional FBP method, in terms of image noise reduction and resolution preservation. PMID:24881498

  14. Quality Control of High-Dose-Rate Brachytherapy: Treatment Delivery Analysis Using Statistical Process Control

    SciTech Connect

    Able, Charles M.; Bright, Megan; Frizzell, Bart

    2013-03-01

    Purpose: Statistical process control (SPC) is a quality control method used to ensure that a process is well controlled and operates with little variation. This study determined whether SPC was a viable technique for evaluating the proper operation of a high-dose-rate (HDR) brachytherapy treatment delivery system. Methods and Materials: A surrogate prostate patient was developed using Vyse ordnance gelatin. A total of 10 metal oxide semiconductor field-effect transistors (MOSFETs) were placed from prostate base to apex. Computed tomography guidance was used to accurately position the first detector in each train at the base. The plan consisted of 12 needles with 129 dwell positions delivering a prescribed peripheral dose of 200 cGy. Sixteen accurate treatment trials were delivered as planned. Subsequently, a number of treatments were delivered with errors introduced, including wrong patient, wrong source calibration, wrong connection sequence, single needle displaced inferiorly 5 mm, and entire implant displaced 2 mm and 4 mm inferiorly. Two process behavior charts (PBC), an individual and a moving range chart, were developed for each dosimeter location. Results: There were 4 false positives resulting from 160 measurements from 16 accurately delivered treatments. For the inaccurately delivered treatments, the PBC indicated that measurements made at the periphery and apex (regions of high-dose gradient) were much more sensitive to treatment delivery errors. All errors introduced were correctly identified by either the individual or the moving range PBC in the apex region. Measurements at the urethra and base were less sensitive to errors. Conclusions: SPC is a viable method for assessing the quality of HDR treatment delivery. Further development is necessary to determine the most effective dose sampling, to ensure reproducible evaluation of treatment delivery accuracy.

  15. The (mis)reporting of statistical results in psychology journals.

    PubMed

    Bakker, Marjan; Wicherts, Jelte M

    2011-09-01

    In order to study the prevalence, nature (direction), and causes of reporting errors in psychology, we checked the consistency of reported test statistics, degrees of freedom, and p values in a random sample of high- and low-impact psychology journals. In a second study, we established the generality of reporting errors in a random sample of recent psychological articles. Our results, on the basis of 281 articles, indicate that around 18% of statistical results in the psychological literature are incorrectly reported. Inconsistencies were more common in low-impact journals than in high-impact journals. Moreover, around 15% of the articles contained at least one statistical conclusion that proved, upon recalculation, to be incorrect; that is, recalculation rendered the previously significant result insignificant, or vice versa. These errors were often in line with researchers' expectations. We classified the most common errors and contacted authors to shed light on the origins of the errors.

  16. Quality control of high-dose-rate brachytherapy: treatment delivery analysis using statistical process control.

    PubMed

    Able, Charles M; Bright, Megan; Frizzell, Bart

    2013-03-01

    Statistical process control (SPC) is a quality control method used to ensure that a process is well controlled and operates with little variation. This study determined whether SPC was a viable technique for evaluating the proper operation of a high-dose-rate (HDR) brachytherapy treatment delivery system. A surrogate prostate patient was developed using Vyse ordnance gelatin. A total of 10 metal oxide semiconductor field-effect transistors (MOSFETs) were placed from prostate base to apex. Computed tomography guidance was used to accurately position the first detector in each train at the base. The plan consisted of 12 needles with 129 dwell positions delivering a prescribed peripheral dose of 200 cGy. Sixteen accurate treatment trials were delivered as planned. Subsequently, a number of treatments were delivered with errors introduced, including wrong patient, wrong source calibration, wrong connection sequence, single needle displaced inferiorly 5 mm, and entire implant displaced 2 mm and 4 mm inferiorly. Two process behavior charts (PBC), an individual and a moving range chart, were developed for each dosimeter location. There were 4 false positives resulting from 160 measurements from 16 accurately delivered treatments. For the inaccurately delivered treatments, the PBC indicated that measurements made at the periphery and apex (regions of high-dose gradient) were much more sensitive to treatment delivery errors. All errors introduced were correctly identified by either the individual or the moving range PBC in the apex region. Measurements at the urethra and base were less sensitive to errors. SPC is a viable method for assessing the quality of HDR treatment delivery. Further development is necessary to determine the most effective dose sampling, to ensure reproducible evaluation of treatment delivery accuracy. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Characterization of adaptive statistical iterative reconstruction algorithm for dose reduction in CT: A pediatric oncology perspective

    SciTech Connect

    Brady, S. L.; Yee, B. S.; Kaufman, R. A.

    2012-09-15

    Purpose: This study demonstrates a means of implementing an adaptive statistical iterative reconstruction (ASiR Trade-Mark-Sign ) technique for dose reduction in computed tomography (CT) while maintaining similar noise levels in the reconstructed image. The effects of image quality and noise texture were assessed at all implementation levels of ASiR Trade-Mark-Sign . Empirically derived dose reduction limits were established for ASiR Trade-Mark-Sign for imaging of the trunk for a pediatric oncology population ranging from 1 yr old through adolescence/adulthood. Methods: Image quality was assessed using metrics established by the American College of Radiology (ACR) CT accreditation program. Each image quality metric was tested using the ACR CT phantom with 0%-100% ASiR Trade-Mark-Sign blended with filtered back projection (FBP) reconstructed images. Additionally, the noise power spectrum (NPS) was calculated for three common reconstruction filters of the trunk. The empirically derived limitations on ASiR Trade-Mark-Sign implementation for dose reduction were assessed using (1, 5, 10) yr old and adolescent/adult anthropomorphic phantoms. To assess dose reduction limits, the phantoms were scanned in increments of increased noise index (decrementing mA using automatic tube current modulation) balanced with ASiR Trade-Mark-Sign reconstruction to maintain noise equivalence of the 0% ASiR Trade-Mark-Sign image. Results: The ASiR Trade-Mark-Sign algorithm did not produce any unfavorable effects on image quality as assessed by ACR criteria. Conversely, low-contrast resolution was found to improve due to the reduction of noise in the reconstructed images. NPS calculations demonstrated that images with lower frequency noise had lower noise variance and coarser graininess at progressively higher percentages of ASiR Trade-Mark-Sign reconstruction; and in spite of the similar magnitudes of noise, the image reconstructed with 50% or more ASiR Trade-Mark-Sign presented a more

  18. SU-E-T-16: Statistical Variability and Confidence Intervals for Planar Dose QA Pass Rates.

    PubMed

    Bailey, D; Nelms, B; Kumaraswamy, L; Attwood, K; Podgorsak, M

    2012-06-01

    The most common metric for comparing measured to calculated dose planes is a pass rate generated using percent difference, distance-to-agreement (DTA), or some combination of the two (e.g. gamma evaluation). The grid of analyzed points often corresponds to a dosimeter array with low areal-density of point detectors. This work examines the statistical uncertainty of planar dose comparison pass rates and proposes methods for establishing confidence intervals for pass rates obtained with low detector-density arrays. Absolute dose planes were acquired via EPID for twenty intensity-modulated fields of varying complexity. Matching calculated dose planes were created via treatment planning system. Pass rates for each dose plane pair (centered to CAX) were calculated with various %/DTA composite analysis techniques. Software was designed to selectively sample the high-density EPID matrix to simulate many low-density measured grids, each representing a different alignment with respect to CAX. Simulations were repeated (100 positional iterations per field) using grids of varying detector-densities and both random and orthogonal point-detector orientation. For each simulation, pass rates were calculated with various composite analysis techniques. Repositioning simulated low-density grids leads to a distribution of possible pass rates for each measured/calculated dose plane pair, independent of whether the detector grid is random or uniform. Distributions can be predicted using a binomial distribution by which a confidence interval (function of sampling density and observed pass rate) is approximated for each pass rate. For example, 95% confidence intervals for IMRT pass rates (2%,2mm) average +/-5.3% and +/-3.8% with 1-detector/cm(2) and 2-detector/cm(2) grids, respectively. Pass rates for low-density array measurements are not absolute and should be reported with both a full description of calculation method and confidence intervals quantifying their uncertainty. Results

  19. STATISTICAL ANALYSIS OF TANK 19F FLOOR SAMPLE RESULTS

    SciTech Connect

    Harris, S.

    2010-09-02

    Representative sampling has been completed for characterization of the residual material on the floor of Tank 19F as per the statistical sampling plan developed by Harris and Shine. Samples from eight locations have been obtained from the tank floor and two of the samples were archived as a contingency. Six samples, referred to in this report as the current scrape samples, have been submitted to and analyzed by SRNL. This report contains the statistical analysis of the floor sample analytical results to determine if further data are needed to reduce uncertainty. Included are comparisons with the prior Mantis samples results to determine if they can be pooled with the current scrape samples to estimate the upper 95% confidence limits (UCL95%) for concentration. Statistical analysis revealed that the Mantis and current scrape sample results are not compatible. Therefore, the Mantis sample results were not used to support the quantification of analytes in the residual material. Significant spatial variability among the current scrape sample results was not found. Constituent concentrations were similar between the North and South hemispheres as well as between the inner and outer regions of the tank floor. The current scrape sample results from all six samples fall within their 3-sigma limits. In view of the results from numerous statistical tests, the data were pooled from all six current scrape samples. As such, an adequate sample size was provided for quantification of the residual material on the floor of Tank 19F. The uncertainty is quantified in this report by an UCL95% on each analyte concentration. The uncertainty in analyte concentration was calculated as a function of the number of samples, the average, and the standard deviation of the analytical results. The UCL95% was based entirely on the six current scrape sample results (each averaged across three analytical determinations).

  20. STATISTICAL ANALYSIS OF TANK 18F FLOOR SAMPLE RESULTS

    SciTech Connect

    Harris, S.

    2010-09-02

    Representative sampling has been completed for characterization of the residual material on the floor of Tank 18F as per the statistical sampling plan developed by Shine [1]. Samples from eight locations have been obtained from the tank floor and two of the samples were archived as a contingency. Six samples, referred to in this report as the current scrape samples, have been submitted to and analyzed by SRNL [2]. This report contains the statistical analysis of the floor sample analytical results to determine if further data are needed to reduce uncertainty. Included are comparisons with the prior Mantis samples results [3] to determine if they can be pooled with the current scrape samples to estimate the upper 95% confidence limits (UCL{sub 95%}) for concentration. Statistical analysis revealed that the Mantis and current scrape sample results are not compatible. Therefore, the Mantis sample results were not used to support the quantification of analytes in the residual material. Significant spatial variability among the current sample results was not found. Constituent concentrations were similar between the North and South hemispheres as well as between the inner and outer regions of the tank floor. The current scrape sample results from all six samples fall within their 3-sigma limits. In view of the results from numerous statistical tests, the data were pooled from all six current scrape samples. As such, an adequate sample size was provided for quantification of the residual material on the floor of Tank 18F. The uncertainty is quantified in this report by an upper 95% confidence limit (UCL{sub 95%}) on each analyte concentration. The uncertainty in analyte concentration was calculated as a function of the number of samples, the average, and the standard deviation of the analytical results. The UCL{sub 95%} was based entirely on the six current scrape sample results (each averaged across three analytical determinations).

  1. Planck 2015 results. XVI. Isotropy and statistics of the CMB

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Akrami, Y.; Aluri, P. K.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Basak, S.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Casaponsa, B.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Contreras, D.; Couchot, F.; Coulais, A.; Crill, B. P.; Cruz, M.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F.-X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Fantaye, Y.; Fergusson, J.; Fernandez-Cobos, R.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Frolov, A.; Galeotta, S.; Galli, S.; Ganga, K.; Gauthier, C.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huang, Z.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kim, J.; Kisner, T. S.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; Liu, H.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Marinucci, D.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mikkelsen, K.; Mitra, S.; Miville-Deschênes, M.-A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Pant, N.; Paoletti, D.; Pasian, F.; Patanchon, G.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Popa, L.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Rotti, A.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Souradeep, T.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Trombetti, T.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Yvon, D.; Zacchei, A.; Zibin, J. P.; Zonca, A.

    2016-09-01

    We test the statistical isotropy and Gaussianity of the cosmic microwave background (CMB) anisotropies using observations made by the Planck satellite. Our results are based mainly on the full Planck mission for temperature, but also include some polarization measurements. In particular, we consider the CMB anisotropy maps derived from the multi-frequency Planck data by several component-separation methods. For the temperature anisotropies, we find excellent agreement between results based on these sky maps over both a very large fraction of the sky and a broad range of angular scales, establishing that potential foreground residuals do not affect our studies. Tests of skewness, kurtosis, multi-normality, N-point functions, and Minkowski functionals indicate consistency with Gaussianity, while a power deficit at large angular scales is manifested in several ways, for example low map variance. The results of a peak statistics analysis are consistent with the expectations of a Gaussian random field. The "Cold Spot" is detected with several methods, including map kurtosis, peak statistics, and mean temperature profile. We thoroughly probe the large-scale dipolar power asymmetry, detecting it with several independent tests, and address the subject of a posteriori correction. Tests of directionality suggest the presence of angular clustering from large to small scales, but at a significance that is dependent on the details of the approach. We perform the first examination of polarization data, finding the morphology of stacked peaks to be consistent with the expectations of statistically isotropic simulations. Where they overlap, these results are consistent with the Planck 2013 analysis based on the nominal mission data and provide our most thorough view of the statistics of the CMB fluctuations to date.

  2. Planck 2015 results: XVI. Isotropy and statistics of the CMB

    DOE PAGES

    Ade, P. A. R.; Aghanim, N.; Akrami, Y.; ...

    2016-09-20

    In this paper, we test the statistical isotropy and Gaussianity of the cosmic microwave background (CMB) anisotropies using observations made by the Planck satellite. Our results are based mainly on the full Planck mission for temperature, but also include some polarization measurements. In particular, we consider the CMB anisotropy maps derived from the multi-frequency Planck data by several component-separation methods. For the temperature anisotropies, we find excellent agreement between results based on these sky maps over both a very large fraction of the sky and a broad range of angular scales, establishing that potential foreground residuals do not affect ourmore » studies. Tests of skewness, kurtosis, multi-normality, N-point functions, and Minkowski functionals indicate consistency with Gaussianity, while a power deficit at large angular scales is manifested in several ways, for example low map variance. The results of a peak statistics analysis are consistent with the expectations of a Gaussian random field. The “Cold Spot” is detected with several methods, including map kurtosis, peak statistics, and mean temperature profile. We thoroughly probe the large-scale dipolar power asymmetry, detecting it with several independent tests, and address the subject of a posteriori correction. Tests of directionality suggest the presence of angular clustering from large to small scales, but at a significance that is dependent on the details of the approach. We perform the first examination of polarization data, finding the morphology of stacked peaks to be consistent with the expectations of statistically isotropic simulations. Finally, where they overlap, these results are consistent with the Planck 2013 analysis based on the nominal mission data and provide our most thorough view of the statistics of the CMB fluctuations to date.« less

  3. Characterization of statistical prior image constrained compressed sensing (PICCS): II. Application to dose reduction

    SciTech Connect

    Lauzier, Pascal Theriault; Chen Guanghong

    2013-02-15

    Purpose: The ionizing radiation imparted to patients during computed tomography exams is raising concerns. This paper studies the performance of a scheme called dose reduction using prior image constrained compressed sensing (DR-PICCS). The purpose of this study is to characterize the effects of a statistical model of x-ray detection in the DR-PICCS framework and its impact on spatial resolution. Methods: Both numerical simulations with known ground truth and in vivo animal dataset were used in this study. In numerical simulations, a phantom was simulated with Poisson noise and with varying levels of eccentricity. Both the conventional filtered backprojection (FBP) and the PICCS algorithms were used to reconstruct images. In PICCS reconstructions, the prior image was generated using two different denoising methods: a simple Gaussian blur and a more advanced diffusion filter. Due to the lack of shift-invariance in nonlinear image reconstruction such as the one studied in this paper, the concept of local spatial resolution was used to study the sharpness of a reconstructed image. Specifically, a directional metric of image sharpness, the so-called pseudopoint spread function (pseudo-PSF), was employed to investigate local spatial resolution. Results: In the numerical studies, the pseudo-PSF was reduced from twice the voxel width in the prior image down to less than 1.1 times the voxel width in DR-PICCS reconstructions when the statistical model was not included. At the same noise level, when statistical weighting was used, the pseudo-PSF width in DR-PICCS reconstructed images varied between 1.5 and 0.75 times the voxel width depending on the direction along which it was measured. However, this anisotropy was largely eliminated when the prior image was generated using diffusion filtering; the pseudo-PSF width was reduced to below one voxel width in that case. In the in vivo study, a fourfold improvement in CNR was achieved while qualitatively maintaining sharpness

  4. Some results of solving statistical-equilibrium equations

    NASA Astrophysics Data System (ADS)

    Damdin, Batmunkh

    2015-08-01

    For the analysis of the profile of the spectral lines of atoms and ions is a system of several equations. Some of these equations are the statistical-equilibrium equations. In this paper we present some results of the solution of the statistical-equilibrium equations for hydrogen lines formed in the solar atmosphere. In solving these equations was considered a macroscopic motion of the plasma. Term, which describes the movement is taken into account in the equation iteratively. Specific calculations are performed on a model of the hydrogen atom with eight levels and continuum at different intensities of radiation in the solar flare. Source functions for the Lyman and Balmer, which are determined by the departure coefficients, is changing because of macroscopic velocity and also of the electron beam, and therefore could be possibly affect the profile of the lines.

  5. Adaptive Statistical Iterative Reconstruction-Applied Ultra-Low-Dose CT with Radiography-Comparable Radiation Dose: Usefulness for Lung Nodule Detection.

    PubMed

    Yoon, Hyun Jung; Chung, Myung Jin; Hwang, Hye Sun; Moon, Jung Won; Lee, Kyung Soo

    2015-01-01

    To assess the performance of adaptive statistical iterative reconstruction (ASIR)-applied ultra-low-dose CT (ULDCT) in detecting small lung nodules. Thirty patients underwent both ULDCT and standard dose CT (SCT). After determining the reference standard nodules, five observers, blinded to the reference standard reading results, independently evaluated SCT and both subsets of ASIR- and filtered back projection (FBP)-driven ULDCT images. Data assessed by observers were compared statistically. Converted effective doses in SCT and ULDCT were 2.81 ± 0.92 and 0.17 ± 0.02 mSv, respectively. A total of 114 lung nodules were detected on SCT as a standard reference. There was no statistically significant difference in sensitivity between ASIR-driven ULDCT and SCT for three out of the five observers (p = 0.678, 0.735, < 0.01, 0.038, and < 0.868 for observers 1, 2, 3, 4, and 5, respectively). The sensitivity of FBP-driven ULDCT was significantly lower than that of ASIR-driven ULDCT in three out of the five observers (p < 0.01 for three observers, and p = 0.064 and 0.146 for two observers). In jackknife alternative free-response receiver operating characteristic analysis, the mean values of figure-of-merit (FOM) for FBP, ASIR-driven ULDCT, and SCT were 0.682, 0.772, and 0.821, respectively, and there were no significant differences in FOM values between ASIR-driven ULDCT and SCT (p = 0.11), but the FOM value of FBP-driven ULDCT was significantly lower than that of ASIR-driven ULDCT and SCT (p = 0.01 and 0.00). Adaptive statistical iterative reconstruction-driven ULDCT delivering a radiation dose of only 0.17 mSv offers acceptable sensitivity in nodule detection compared with SCT and has better performance than FBP-driven ULDCT.

  6. The adaptive statistical iterative reconstruction-V technique for radiation dose reduction in abdominal CT: comparison with the adaptive statistical iterative reconstruction technique.

    PubMed

    Kwon, Heejin; Cho, Jinhan; Oh, Jongyeong; Kim, Dongwon; Cho, Junghyun; Kim, Sanghyun; Lee, Sangyun; Lee, Jihyun

    2015-10-01

    To investigate whether reduced radiation dose abdominal CT images reconstructed with adaptive statistical iterative reconstruction V (ASIR-V) compromise the depiction of clinically competent features when compared with the currently used routine radiation dose CT images reconstructed with ASIR. 27 consecutive patients (mean body mass index: 23.55 kg m(-2) underwent CT of the abdomen at two time points. At the first time point, abdominal CT was scanned at 21.45 noise index levels of automatic current modulation at 120 kV. Images were reconstructed with 40% ASIR, the routine protocol of Dong-A University Hospital. At the second time point, follow-up scans were performed at 30 noise index levels. Images were reconstructed with filtered back projection (FBP), 40% ASIR, 30% ASIR-V, 50% ASIR-V and 70% ASIR-V for the reduced radiation dose. Both quantitative and qualitative analyses of image quality were conducted. The CT dose index was also recorded. At the follow-up study, the mean dose reduction relative to the currently used common radiation dose was 35.37% (range: 19-49%). The overall subjective image quality and diagnostic acceptability of the 50% ASIR-V scores at the reduced radiation dose were nearly identical to those recorded when using the initial routine-dose CT with 40% ASIR. Subjective ratings of the qualitative analysis revealed that of all reduced radiation dose CT series reconstructed, 30% ASIR-V and 50% ASIR-V were associated with higher image quality with lower noise and artefacts as well as good sharpness when compared with 40% ASIR and FBP. However, the sharpness score at 70% ASIR-V was considered to be worse than that at 40% ASIR. Objective image noise for 50% ASIR-V was 34.24% and 46.34% which was lower than 40% ASIR and FBP. Abdominal CT images reconstructed with ASIR-V facilitate radiation dose reductions of to 35% when compared with the ASIR. This study represents the first clinical research experiment to use ASIR-V, the newest version of

  7. Statistical Analysis of NAS Parallel Benchmarks and LINPACK Results

    NASA Technical Reports Server (NTRS)

    Meuer, Hans-Werner; Simon, Horst D.; Strohmeier, Erich; Lasinski, T. A. (Technical Monitor)

    1994-01-01

    In the last three years extensive performance data have been reported for parallel machines both based on the NAS Parallel Benchmarks, and on LINPACK. In this study we have used the reported benchmark results and performed a number of statistical experiments using factor, cluster, and regression analyses. In addition to the performance results of LINPACK and the eight NAS parallel benchmarks, we have also included peak performance of the machine, and the LINPACK n and n(sub 1/2) values. Some of the results and observations can be summarized as follows: 1) All benchmarks are strongly correlated with peak performance. 2) LINPACK and EP have each a unique signature. 3) The remaining NPB can grouped into three groups as follows: (CG and IS), (LU and SP), and (MG, FT, and BT). Hence three (or four with EP) benchmarks are sufficient to characterize the overall NPB performance. Our poster presentation will follow a standard poster format, and will present the data of our statistical analysis in detail.

  8. Full dose reduction potential of statistical iterative reconstruction for head CT protocols in a predominantly pediatric population

    PubMed Central

    Mirro, Amy E.; Brady, Samuel L.; Kaufman, Robert. A.

    2016-01-01

    Purpose To implement the maximum level of statistical iterative reconstruction that can be used to establish dose-reduced head CT protocols in a primarily pediatric population. Methods Select head examinations (brain, orbits, sinus, maxilla and temporal bones) were investigated. Dose-reduced head protocols using an adaptive statistical iterative reconstruction (ASiR) were compared for image quality with the original filtered back projection (FBP) reconstructed protocols in phantom using the following metrics: image noise frequency (change in perceived appearance of noise texture), image noise magnitude, contrast-to-noise ratio (CNR), and spatial resolution. Dose reduction estimates were based on computed tomography dose index (CTDIvol) values. Patient CTDIvol and image noise magnitude were assessed in 737 pre and post dose reduced examinations. Results Image noise texture was acceptable up to 60% ASiR for Soft reconstruction kernel (at both 100 and 120 kVp), and up to 40% ASiR for Standard reconstruction kernel. Implementation of 40% and 60% ASiR led to an average reduction in CTDIvol of 43% for brain, 41% for orbits, 30% maxilla, 43% for sinus, and 42% for temporal bone protocols for patients between 1 month and 26 years, while maintaining an average noise magnitude difference of 0.1% (range: −3% to 5%), improving CNR of low contrast soft tissue targets, and improving spatial resolution of high contrast bony anatomy, as compared to FBP. Conclusion The methodology in this study demonstrates a methodology for maximizing patient dose reduction and maintaining image quality using statistical iterative reconstruction for a primarily pediatric population undergoing head CT examination. PMID:27056425

  9. Ventilatory effects of low-dose paraoxon result from central muscarinic effects

    SciTech Connect

    Houze, Pascal; Pronzola, Laetita; Kayouka, Maya; Villa, Antoine; Debray, Marcel; Baud, Frederic J.

    2008-12-01

    Paraoxon induces respiratory toxicity. Atropine completely reversed parathion- and paraoxon-induced respiratory toxicity. The aim of this study was to assess the peripheral or central origin of ventilatory effects of low-dose paraoxon. Male Sprague-Dawley rats were given paraoxon 0.215 mg/kg subcutaneously and treated with either atropine (10 mg/kg sc) or ascending doses of methylatropine of 5.42 (equimolar to that of atropine), 54.2, and 542 mg/kg administered subcutaneously 30 min after paraoxon. Ventilation at rest was assessed using whole-body plethysmography and rat temperature using infra-red telemetry. Results are expressed as mean {+-} SE. Statistical analysis used two-way ANOVA for repeated measurements. Paraoxon induced a significant decrease in temperature 30 min after injection lasting the 90 min of the study period. This effect was partially corrected by atropine, but not by methylatropine whatever the dose. Paraoxon induced a decrease in respiratory rate resulting from an increase in expiratory time associated with an increase in tidal volume. Atropine completely reversed the ventilatory effects of low-dose paraoxon while the equimolar dose of methylatropine had no significant effects. The 54.2 and 542 mg/kg doses of methylatropine had no significant effects. Atropine crosses the blood-brain barrier and reverses peripheral and central muscarinic effects. In contrast, methylatropine does not cross the blood-brain barrier. Atropine completely reversed the ventilatory effects of low-dose paraoxon, while methylatropine had no significant effects at doses up to 100-fold the equimolar dose of atropine. We conclude that the ventilatory effects of low-dose paraoxon are mediated by disrupted muscarinic signaling in the central nervous system.

  10. Sharing brain mapping statistical results with the neuroimaging data model.

    PubMed

    Maumet, Camille; Auer, Tibor; Bowring, Alexander; Chen, Gang; Das, Samir; Flandin, Guillaume; Ghosh, Satrajit; Glatard, Tristan; Gorgolewski, Krzysztof J; Helmer, Karl G; Jenkinson, Mark; Keator, David B; Nichols, B Nolan; Poline, Jean-Baptiste; Reynolds, Richard; Sochat, Vanessa; Turner, Jessica; Nichols, Thomas E

    2016-12-06

    Only a tiny fraction of the data and metadata produced by an fMRI study is finally conveyed to the community. This lack of transparency not only hinders the reproducibility of neuroimaging results but also impairs future meta-analyses. In this work we introduce NIDM-Results, a format specification providing a machine-readable description of neuroimaging statistical results along with key image data summarising the experiment. NIDM-Results provides a unified representation of mass univariate analyses including a level of detail consistent with available best practices. This standardized representation allows authors to relay methods and results in a platform-independent regularized format that is not tied to a particular neuroimaging software package. Tools are available to export NIDM-Result graphs and associated files from the widely used SPM and FSL software packages, and the NeuroVault repository can import NIDM-Results archives. The specification is publically available at: http://nidm.nidash.org/specs/nidm-results.html.

  11. Sharing brain mapping statistical results with the neuroimaging data model

    PubMed Central

    Maumet, Camille; Auer, Tibor; Bowring, Alexander; Chen, Gang; Das, Samir; Flandin, Guillaume; Ghosh, Satrajit; Glatard, Tristan; Gorgolewski, Krzysztof J.; Helmer, Karl G.; Jenkinson, Mark; Keator, David B.; Nichols, B. Nolan; Poline, Jean-Baptiste; Reynolds, Richard; Sochat, Vanessa; Turner, Jessica; Nichols, Thomas E.

    2016-01-01

    Only a tiny fraction of the data and metadata produced by an fMRI study is finally conveyed to the community. This lack of transparency not only hinders the reproducibility of neuroimaging results but also impairs future meta-analyses. In this work we introduce NIDM-Results, a format specification providing a machine-readable description of neuroimaging statistical results along with key image data summarising the experiment. NIDM-Results provides a unified representation of mass univariate analyses including a level of detail consistent with available best practices. This standardized representation allows authors to relay methods and results in a platform-independent regularized format that is not tied to a particular neuroimaging software package. Tools are available to export NIDM-Result graphs and associated files from the widely used SPM and FSL software packages, and the NeuroVault repository can import NIDM-Results archives. The specification is publically available at: http://nidm.nidash.org/specs/nidm-results.html. PMID:27922621

  12. Standard error of inverse prediction for dose-response relationship: approximate and exact statistical inference.

    PubMed

    Demidenko, Eugene; Williams, Benjamin B; Flood, Ann Barry; Swartz, Harold M

    2013-05-30

    This paper develops a new metric, the standard error of inverse prediction (SEIP), for a dose-response relationship (calibration curve) when dose is estimated from response via inverse regression. SEIP can be viewed as a generalization of the coefficient of variation to regression problem when x is predicted using y-value. We employ nonstandard statistical methods to treat the inverse prediction, which has an infinite mean and variance due to the presence of a normally distributed variable in the denominator. We develop confidence intervals and hypothesis testing for SEIP on the basis of the normal approximation and using the exact statistical inference based on the noncentral t-distribution. We derive the power functions for both approaches and test them via statistical simulations. The theoretical SEIP, as the ratio of the regression standard error to the slope, is viewed as reciprocal of the signal-to-noise ratio, a popular measure of signal processing. The SEIP, as a figure of merit for inverse prediction, can be used for comparison of calibration curves with different dependent variables and slopes. We illustrate our theory with electron paramagnetic resonance tooth dosimetry for a rapid estimation of the radiation dose received in the event of nuclear terrorism.

  13. Impact of adaptive statistical iterative reconstruction on radiation dose in evaluation of trauma patients

    PubMed Central

    Maxfield, Mark W.; Schuster, Kevin M.; McGillicuddy, Edward A.; Young, Calvin J.; Ghita, Monica; Bokhari, S.A. Jamal; Oliva, Isabel B.; Brink, James A.; Davis, Kimberly A.

    2013-01-01

    BACKGROUND A recent study showed that computed tomographic (CT) scans contributed 93% of radiation exposure of 177 patients admitted to our Level I trauma center. Adaptive statistical iterative reconstruction (ASIR) is an algorithm that reduces the noise level in reconstructed images and therefore allows the use of less ionizing radiation during CT scans without significantly affecting image quality. ASIR was instituted on all CT scans performed on trauma patients in June 2009. Our objective was to determine if implementation of ASIR reduced radiation dose without compromising patient outcomes. METHODS We identified 300 patients activating the trauma system before and after the implementation of ASIR imaging. After applying inclusion criteria, 245 charts were reviewed. Baseline demographics, presenting characteristics, number of delayed diagnoses, and missed injuries were recorded. The postexamination volume CT dose index (CTDIvol) and dose-length product (DLP)reported by the scanner for CT scans of the chest, abdomen, and pelvis and CT scans of the brain and cervical spine were recorded. Subjective image quality was compared between the two groups. RESULTS For CT scans of the chest, abdomen, and pelvis, the mean CTDIvol(17.1 mGy vs. 14.2 mGy; p < 0.001) and DLP (1,165 mGy·cm vs. 1,004 mGy·cm; p < 0.001) was lower for studies performed with ASIR. For CT scans of the brain and cervical spine, the mean CTDIvol(61.7 mGy vs. 49.6 mGy; p < 0.001) and DLP (1,327 mGy·cm vs. 1,067 mGy·cm; p < 0.001) was lower for studies performed with ASIR. There was no subjective difference in image quality between ASIR and non-ASIR scans. All CT scans were deemed of good or excellent image quality. There were no delayed diagnoses or missed injuries related to CT scanning identified in either group. CONCLUSION Implementation of ASIR imaging for CT scans performed on trauma patients led to a nearly 20% reduction in ionizing radiation without compromising outcomes or image quality

  14. Statistics

    Cancer.gov

    Links to sources of cancer-related statistics, including the Surveillance, Epidemiology and End Results (SEER) Program, SEER-Medicare datasets, cancer survivor prevalence data, and the Cancer Trends Progress Report.

  15. The geomagnetic storms of 2015: Statistical analysis and forecasting results

    NASA Astrophysics Data System (ADS)

    Paouris, Evangelos; Gerontidou, Maria; Mavromichalaki, Helen

    2016-04-01

    The year 2015 was characterized by long geomagnetic quiet periods with a lot of geomagnetically active breaks although it is on the declining phase of the current solar cycle. As a result a number of geomagnetic storms in the G1 up to G4 scale were noticed. In this work the characteristics of these geomagnetic storms like the scale level, the origin of the storm (CME or CIR) and the duration have been studied. Furthermore, a statistical analysis of these events and a comparative study of the forecasting and the actual geomagnetic conditions are performed using data from the NOAA space weather forecasting center and from the Athens Space Weather Forecasting Center as well. These forecasting centers estimate and provide every day the geomagnetic conditions for the upcoming days giving the values of the geomagnetic index Ap. The forecasting values of Ap index for the year 2015 from these two centers and their comparison in terms of the actual values are discussed.

  16. Planck 2013 results. XXIII. Isotropy and statistics of the CMB

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Bartolo, N.; Battaner, E.; Battye, R.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R. C.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Cruz, M.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Fantaye, Y.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Frommert, M.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Hansen, M.; Hanson, D.; Harrison, D. L.; Helou, G.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kim, J.; Kisner, T. S.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leahy, J. P.; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Mangilli, A.; Marinucci, D.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McEwen, J. D.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mikkelsen, K.; Mitra, S.; Miville-Deschênes, M.-A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Peiris, H. V.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pogosyan, D.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Racine, B.; Räth, C.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rotti, A.; Roudier, G.; Rubiño-Martín, J. A.; Ruiz-Granados, B.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Souradeep, T.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutter, P.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Türler, M.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Varis, J.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; White, M.; Wilkinson, A.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-11-01

    The two fundamental assumptions of the standard cosmological model - that the initial fluctuations are statistically isotropic and Gaussian - are rigorously tested using maps of the cosmic microwave background (CMB) anisotropy from the Planck satellite. The detailed results are based on studies of four independent estimates of the CMB that are compared to simulations using a fiducial ΛCDM model and incorporating essential aspects of the Planck measurement process. Deviations from isotropy have been found and demonstrated to be robust against component separation algorithm, mask choice, and frequency dependence. Many of these anomalies were previously observed in the WMAP data, and are now confirmed at similar levels of significance (about 3σ). However, we find little evidence of non-Gaussianity, with the exception of a few statistical signatures that seem to be associated with specific anomalies. In particular, we find that the quadrupole-octopole alignment is also connected to a low observed variance in the CMB signal. A power asymmetry is now found to persist on scales corresponding to about ℓ = 600 and can be described in the low-ℓ regime by a phenomenological dipole modulation model. However, any primordial power asymmetry is strongly scale-dependent and does not extend toarbitrarily small angular scales. Finally, it is plausible that some of these features may be reflected in the angular power spectrum of the data, which shows a deficit of power on similar scales. Indeed, when the power spectra of two hemispheres defined by a preferred direction are considered separately, one shows evidence of a deficit in power, while its opposite contains oscillations between odd and even modes that may be related to the parity violation and phase correlations also detected in the data. Although these analyses represent a step forward in building an understanding of the anomalies, a satisfactory explanation based on physically motivated models is still lacking.

  17. STATISTICAL ANALYSIS OF TANK 5 FLOOR SAMPLE RESULTS

    SciTech Connect

    Shine, E.

    2012-03-14

    Sampling has been completed for the characterization of the residual material on the floor of Tank 5 in the F-Area Tank Farm at the Savannah River Site (SRS), near Aiken, SC. The sampling was performed by Savannah River Remediation (SRR) LLC using a stratified random sampling plan with volume-proportional compositing. The plan consisted of partitioning the residual material on the floor of Tank 5 into three non-overlapping strata: two strata enclosed accumulations, and a third stratum consisted of a thin layer of material outside the regions of the two accumulations. Each of three composite samples was constructed from five primary sample locations of residual material on the floor of Tank 5. Three of the primary samples were obtained from the stratum containing the thin layer of material, and one primary sample was obtained from each of the two strata containing an accumulation. This report documents the statistical analyses of the analytical results for the composite samples. The objective of the analysis is to determine the mean concentrations and upper 95% confidence (UCL95) bounds for the mean concentrations for a set of analytes in the tank residuals. The statistical procedures employed in the analyses were consistent with the Environmental Protection Agency (EPA) technical guidance by Singh and others [2010]. Savannah River National Laboratory (SRNL) measured the sample bulk density, nonvolatile beta, gross alpha, radionuclide, inorganic, and anion concentrations three times for each of the composite samples. The analyte concentration data were partitioned into three separate groups for further analysis: analytes with every measurement above their minimum detectable concentrations (MDCs), analytes with no measurements above their MDCs, and analytes with a mixture of some measurement results above and below their MDCs. The means, standard deviations, and UCL95s were computed for the analytes in the two groups that had at least some measurements above their

  18. Statistical Analysis of Tank 5 Floor Sample Results

    SciTech Connect

    Shine, E. P.

    2013-01-31

    Sampling has been completed for the characterization of the residual material on the floor of Tank 5 in the F-Area Tank Farm at the Savannah River Site (SRS), near Aiken, SC. The sampling was performed by Savannah River Remediation (SRR) LLC using a stratified random sampling plan with volume-proportional compositing. The plan consisted of partitioning the residual material on the floor of Tank 5 into three non-overlapping strata: two strata enclosed accumulations, and a third stratum consisted of a thin layer of material outside the regions of the two accumulations. Each of three composite samples was constructed from five primary sample locations of residual material on the floor of Tank 5. Three of the primary samples were obtained from the stratum containing the thin layer of material, and one primary sample was obtained from each of the two strata containing an accumulation. This report documents the statistical analyses of the analytical results for the composite samples. The objective of the analysis is to determine the mean concentrations and upper 95% confidence (UCL95) bounds for the mean concentrations for a set of analytes in the tank residuals. The statistical procedures employed in the analyses were consistent with the Environmental Protection Agency (EPA) technical guidance by Singh and others [2010]. Savannah River National Laboratory (SRNL) measured the sample bulk density, nonvolatile beta, gross alpha, and the radionuclide1, elemental, and chemical concentrations three times for each of the composite samples. The analyte concentration data were partitioned into three separate groups for further analysis: analytes with every measurement above their minimum detectable concentrations (MDCs), analytes with no measurements above their MDCs, and analytes with a mixture of some measurement results above and below their MDCs. The means, standard deviations, and UCL95s were computed for the analytes in the two groups that had at least some measurements

  19. Statistical Analysis Of Tank 5 Floor Sample Results

    SciTech Connect

    Shine, E. P.

    2012-08-01

    Sampling has been completed for the characterization of the residual material on the floor of Tank 5 in the F-Area Tank Farm at the Savannah River Site (SRS), near Aiken, SC. The sampling was performed by Savannah River Remediation (SRR) LLC using a stratified random sampling plan with volume-proportional compositing. The plan consisted of partitioning the residual material on the floor of Tank 5 into three non-overlapping strata: two strata enclosed accumulations, and a third stratum consisted of a thin layer of material outside the regions of the two accumulations. Each of three composite samples was constructed from five primary sample locations of residual material on the floor of Tank 5. Three of the primary samples were obtained from the stratum containing the thin layer of material, and one primary sample was obtained from each of the two strata containing an accumulation. This report documents the statistical analyses of the analytical results for the composite samples. The objective of the analysis is to determine the mean concentrations and upper 95% confidence (UCL95) bounds for the mean concentrations for a set of analytes in the tank residuals. The statistical procedures employed in the analyses were consistent with the Environmental Protection Agency (EPA) technical guidance by Singh and others [2010]. Savannah River National Laboratory (SRNL) measured the sample bulk density, nonvolatile beta, gross alpha, and the radionuclide, elemental, and chemical concentrations three times for each of the composite samples. The analyte concentration data were partitioned into three separate groups for further analysis: analytes with every measurement above their minimum detectable concentrations (MDCs), analytes with no measurements above their MDCs, and analytes with a mixture of some measurement results above and below their MDCs. The means, standard deviations, and UCL95s were computed for the analytes in the two groups that had at least some measurements

  20. Evaluation of statistical tools used in short-term repeated dose administration toxicity studies with rodents.

    PubMed

    Kobayashi, Katsumi; Pillai, K Sadasivan; Sakuratani, Yuki; Abe, Takemaru; Kamata, Eiichi; Hayashi, Makoto

    2008-02-01

    In order to know the different statistical tools used to analyze the data obtained from twenty-eight-day repeated dose oral toxicity studies with rodents and the impact of these statistical tools on interpretation of data obtained from the studies, study reports of 122 numbers of twenty-eight-day repeated dose oral toxicity studies conducted in rats were examined. It was found that both complex and easy routes of decision trees were followed for the analysis of the quantitative data. These tools include Scheffe's test, non-parametric type Dunnett's and Scheffe's tests with very low power. Few studies used the non-parametric Dunnett type test and Mann-Whitney's U test. Though Chi-square and Fisher's tests are widely used for analysis of qualitative data, their sensitivity to detect a treatment-related effect is questionable. Mann-Whitney's U test has better sensitivity to analyze qualitative data than the chi-square and Fisher's tests. We propose Dunnett's test for analysis of quantitative data obtained from twenty-eight-day repeated dose oral toxicity tests and for qualitative data, Mann-Whitney's U test. For both tests, one-sided test with p=0.05 may be applied.

  1. Statistical methods for clinical verification of dose response parameters related to esophageal stricture and AVM obliteration from radiotherapy

    NASA Astrophysics Data System (ADS)

    Mavroidis, Panayiotis; Lind, Bengt K.; Theodorou, Kyriaki; Laurell, Göran; Fernberg, Jan-Olof; Lefkopoulos, Dimitrios; Kappas, Constantin; Brahme, Anders

    2004-08-01

    The purpose of this work is to provide some statistical methods for evaluating the predictive strength of radiobiological models and the validity of dose-response parameters for tumour control and normal tissue complications. This is accomplished by associating the expected complication rates, which are calculated using different models, with the clinical follow-up records. These methods are applied to 77 patients who received radiation treatment for head and neck cancer and 85 patients who were treated for arteriovenous malformation (AVM). The three-dimensional dose distribution delivered to esophagus and AVM nidus and the clinical follow-up results were available for each patient. Dose-response parameters derived by a maximum likelihood fitting were used as a reference to evaluate their compatibility with the examined treatment methodologies. The impact of the parameter uncertainties on the dose-response curves is demonstrated. The clinical utilization of the radiobiological parameters is illustrated. The radiobiological models (relative seriality and linear Poisson) and the reference parameters are validated to prove their suitability in reproducing the treatment outcome pattern of the patient material studied (through the probability of finding a worse fit, area under the ROC curve and khgr2 test). The analysis was carried out for the upper 5 cm of the esophagus (proximal esophagus) where all the strictures are formed, and the total volume of AVM. The estimated confidence intervals of the dose-response curves appear to have a significant supporting role on their clinical implementation and use.

  2. Reducing statistical uncertainties in simulated organ doses of phantoms immersed in water

    SciTech Connect

    Hiller, Mauritius M.; Veinot, Kenneth G.; Easterly, Clay E.; Hertel, Nolan E.; Eckerman, Keith F.; Bellamy, Michael B.

    2016-08-13

    In this study, methods are addressed to reduce the computational time to compute organ-dose rate coefficients using Monte Carlo techniques. Several variance reduction techniques are compared including the reciprocity method, importance sampling, weight windows and the use of the ADVANTG software package. For low-energy photons, the runtime was reduced by a factor of 105 when using the reciprocity method for kerma computation for immersion of a phantom in contaminated water. This is particularly significant since impractically long simulation times are required to achieve reasonable statistical uncertainties in organ dose for low-energy photons in this source medium and geometry. Although the MCNP Monte Carlo code is used in this paper, the reciprocity technique can be used equally well with other Monte Carlo codes.

  3. Reducing statistical uncertainties in simulated organ doses of phantoms immersed in water

    DOE PAGES

    Hiller, Mauritius M.; Veinot, Kenneth G.; Easterly, Clay E.; ...

    2016-08-13

    In this study, methods are addressed to reduce the computational time to compute organ-dose rate coefficients using Monte Carlo techniques. Several variance reduction techniques are compared including the reciprocity method, importance sampling, weight windows and the use of the ADVANTG software package. For low-energy photons, the runtime was reduced by a factor of 105 when using the reciprocity method for kerma computation for immersion of a phantom in contaminated water. This is particularly significant since impractically long simulation times are required to achieve reasonable statistical uncertainties in organ dose for low-energy photons in this source medium and geometry. Although themore » MCNP Monte Carlo code is used in this paper, the reciprocity technique can be used equally well with other Monte Carlo codes.« less

  4. Model-based iterative reconstruction in ultra-low-dose pediatric chest CT: comparison with adaptive statistical iterative reconstruction.

    PubMed

    Kim, Hae Jin; Yoo, So-Young; Jeon, Tae Yeon; Kim, Ji Hye

    2016-01-01

    To evaluate image quality and dose reduction of ultra-low-dose pediatric chest CT reconstructed with model-based iterative reconstruction (MBIR), as compared with adaptive statistical iterative reconstruction (ASIR). Fifty-seven patients (mean age 14 years, M:F=31:26) who underwent ultra-low-dose chest CT reconstructed with both MBIR and ASIR were enrolled in the study. The subjective and objective image qualities of both reconstruction techniques were assessed by 3 radiologists, and compared using statistical analysis. We also evaluated radiation dose of ultra-low-dose chest CT as well as degree of dose reduction in comparison to the prior CT (either standard dose or reduced dose protocol) available in 36 patients. The image quality of MBIR was superior to ASIR both subjectively and objectively. While MBIR showed preserved diagnostic acceptability in 100%, ASIR showed 92% at mean 0.31 mSv (range, 0.13-0.57 mSv) ultra-low-dose CT. In the 36 patients who underwent the prior CT, mean decrease in size-specific dose estimate (SSDE) and dose length product (DLP) at ultra-low-dose CT was 88% (range, 34% - 98%) and 86% (range,42% - 99%), respectively. MBIR significantly improves image quality, as compared to ASIR. Furthermore, MBIR facilitates diagnostically acceptable ultra-low-dose chest CT with nearly 90% less radiation. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Deriving dose limits for warnings in electronic prescribing systems: statistical analysis of prescription data at University Hospital Birmingham, UK.

    PubMed

    Coleman, Jamie J; Hodson, James; Ferner, Robin E

    2012-04-01

    : Electronic decision support can reduce medication errors, and dose-range checking is one element of that support. : The aim of this study was to design an approach to setting upper dose warning limits in electronic prescribing systems where there are historical data on dosing. : We used historical data on 56 drug-form combinations for which over 100 prescriptions had been issued between 1 June 2009 and 31 May 2010 in a bespoke electronic prescribing system at University Hospital Birmingham, UK. First, two experts derived dose limits for each drug-form combination, then the drugs were randomly divided into a training set and a test set. A variation of the 'Nearest Rank' approach to estimate statistical limits was used to derive the percentile with the optimal sensitivity and specificity. : For the 28 drug-form combinations in the test set, the 86th percentile of dose gave a mean sensitivity of 95.3% and a mean specificity of 97.9% for warning limits, representing the highest reasonable dose; the 96th percentile gave a mean sensitivity of 90.2% and mean specificity of 99.5% for disallow limits, beyond which no dose should be prescribed. : Dosing decision support within electronic prescribing systems can be derived by statistical analysis of historical prescription data. We advocate a combined theoretical and statistical derivation of dose checking rules in order to ensure that prescribers are alerted appropriately to potentially toxic doses.

  6. Rigorous results of nonequilibrium statistical physics and their experimental verification

    NASA Astrophysics Data System (ADS)

    Pitaevskii, Lev P.

    2011-06-01

    Rigorous relations of nonequilibrium statistical physics are discussed. An arbitrary system brought into a strongly nonequilibrium state by an external time-dependent impact is considered. Based on the Hamiltonian formalism of classical mechanics, the Bochkov-Kuzovlev equality, the Jarzynski equality, and Crooks reversal relations valid for fluctuations in the work done on a system are derived. Verification of these equalities in mechanical experiments with a torsion pendulum and biological objects (folded ribonucleic acids) is described.

  7. Some Results in Noise Filtering by Use of Local Statistics.

    DTIC Science & Technology

    1981-01-30

    address: Dept. of Automation, Tsinghua University , Beijing, People’s Republic of China. J**Iermanent address: Beijing Institute of Posts and...IN NCISE FILTERING BY USE CGF LOCAL STATISTICS F. F. Yan* P. F. Li** Department of Electrical Engineering Southeastern assachusetts University North...experimental study an uniform noise (G =300) was added. *Permanent Address: Dept. of Automation, TsinhIka University Beijing, People’s Republic of China

  8. Comparison of Nine Statistical Model Based Warfarin Pharmacogenetic Dosing Algorithms Using the Racially Diverse International Warfarin Pharmacogenetic Consortium Cohort Database.

    PubMed

    Liu, Rong; Li, Xi; Zhang, Wei; Zhou, Hong-Hao

    2015-01-01

    Multiple linear regression (MLR) and machine learning techniques in pharmacogenetic algorithm-based warfarin dosing have been reported. However, performances of these algorithms in racially diverse group have never been objectively evaluated and compared. In this literature-based study, we compared the performances of eight machine learning techniques with those of MLR in a large, racially-diverse cohort. MLR, artificial neural network (ANN), regression tree (RT), multivariate adaptive regression splines (MARS), boosted regression tree (BRT), support vector regression (SVR), random forest regression (RFR), lasso regression (LAR) and Bayesian additive regression trees (BART) were applied in warfarin dose algorithms in a cohort from the International Warfarin Pharmacogenetics Consortium database. Covariates obtained by stepwise regression from 80% of randomly selected patients were used to develop algorithms. To compare the performances of these algorithms, the mean percentage of patients whose predicted dose fell within 20% of the actual dose (mean percentage within 20%) and the mean absolute error (MAE) were calculated in the remaining 20% of patients. The performances of these techniques in different races, as well as the dose ranges of therapeutic warfarin were compared. Robust results were obtained after 100 rounds of resampling. BART, MARS and SVR were statistically indistinguishable and significantly out performed all the other approaches in the whole cohort (MAE: 8.84-8.96 mg/week, mean percentage within 20%: 45.88%-46.35%). In the White population, MARS and BART showed higher mean percentage within 20% and lower mean MAE than those of MLR (all p values < 0.05). In the Asian population, SVR, BART, MARS and LAR performed the same as MLR. MLR and LAR optimally performed among the Black population. When patients were grouped in terms of warfarin dose range, all machine learning techniques except ANN and LAR showed significantly higher mean percentage within 20

  9. Patient-specific minimum-dose imaging protocols for statistical image reconstruction in C-arm cone-beam CT using correlated noise injection

    NASA Astrophysics Data System (ADS)

    Wang, A. S.; Stayman, J. W.; Otake, Y.; Khanna, A. J.; Gallia, G. L.; Siewerdsen, J. H.

    2014-03-01

    Purpose: A new method for accurately portraying the impact of low-dose imaging techniques in C-arm cone-beam CT (CBCT) is presented and validated, allowing identification of minimum-dose protocols suitable to a given imaging task on a patient-specific basis in scenarios that require repeat intraoperative scans. Method: To accurately simulate lower-dose techniques and account for object-dependent noise levels (x-ray quantum noise and detector electronics noise) and correlations (detector blur), noise of the proper magnitude and correlation was injected into the projections from an initial CBCT acquired at the beginning of a procedure. The resulting noisy projections were then reconstructed to yield low-dose preview (LDP) images that accurately depict the image quality at any level of reduced dose in both filtered backprojection and statistical image reconstruction. Validation studies were conducted on a mobile C-arm, with the noise injection method applied to images of an anthropomorphic head phantom and cadaveric torso across a range of lower-dose techniques. Results: Comparison of preview and real CBCT images across a full range of techniques demonstrated accurate noise magnitude (within ~5%) and correlation (matching noise-power spectrum, NPS). Other image quality characteristics (e.g., spatial resolution, contrast, and artifacts associated with beam hardening and scatter) were also realistically presented at all levels of dose and across reconstruction methods, including statistical reconstruction. Conclusion: Generating low-dose preview images for a broad range of protocols gives a useful method to select minimum-dose techniques that accounts for complex factors of imaging task, patient-specific anatomy, and observer preference. The ability to accurately simulate the influence of low-dose acquisition in statistical reconstruction provides an especially valuable means of identifying low-dose limits in a manner that does not rely on a model for the nonlinear

  10. Austrian results from Matroshka poncho and organ dose determination

    NASA Astrophysics Data System (ADS)

    Hajek, M.; Bergmann, R.; Fugger, M.; Vana, N.

    Cosmic rays in low-earth orbits LEO primarily consist of high-energy charged particles originating from galactic cosmic radiation GCR energetic solar particle events SPE and trapped radiation belts These radiations of high linear energy transfer LET generally inflict greater biological damage than that resulting from typical terrestrial radiation hazards Particle and energy spectra are attenuated in interaction processes within shielding structures and within the human body Reliable assessment of health risks to astronaut crews is pivotal in the design of future expeditions into interplanetary space and requires knowledge of absorbed radiation doses in critical radiosensitive organs and tissues The European Space Agency ESA Matroshka experiment---conducted under the aegis of the German Aerospace Center DLR ---is aimed at simulating an astronaut s body during extravehicular activities EVA Matroshka basically consists of a human phantom torso attached to a base structure and covered with a protective carbon-fibre container acting as a spacesuit model The phantom is divided into 33 tissue-equivalent polyurethane slices of specific density for tissue and organs Natural bones are embedded Channels and cut-outs enable accommodation of active and passive radiation monitors The torso is dressed by a skin-equivalent poncho which is also designed for dosimeter integration The phantom houses in total 7 active and more than 6000 passive radiation sensors Thereof the Atomic Institute of the Austrian Universities ATI provided more than

  11. MDCT arthrography of the hip: value of the adaptive statistical iterative reconstruction technique and potential for radiation dose reduction.

    PubMed

    Tobalem, Frank; Dugert, Eric; Verdun, Francis R; Dunet, Vincent; Ott, Julien G; Rudiger, Hannes A; Cherix, Stephane; Meuli, Reto; Becce, Fabio

    2014-12-01

    The purpose of this article is to assess the effect of the adaptive statistical iterative reconstruction (ASIR) technique on image quality in hip MDCT arthrography and to evaluate its potential for reducing radiation dose. Thirty-seven patients examined with hip MDCT arthrography were prospectively randomized into three different protocols: one with a regular dose (volume CT dose index [CTDIvol], 38.4 mGy) and two with a reduced dose (CTDIvol, 24.6 or 15.4 mGy). Images were reconstructed using filtered back projection (FBP) and four increasing percentages of ASIR (30%, 50%, 70%, and 90%). Image noise and contrast-to-noise ratio (CNR) were measured. Two musculoskeletal radiologists independently evaluated several anatomic structures and image quality parameters using a 4-point scale. They also jointly assessed acetabular labrum tears and articular cartilage lesions. With decreasing radiation dose level, image noise statistically significantly increased (p=0.0009) and CNR statistically significantly decreased (p=0.001). We also found a statistically significant reduction in noise (p=0.0001) and increase in CNR (p≤0.003) with increasing percentage of ASIR; in addition, we noted statistically significant increases in image quality scores for the labrum and cartilage, subchondral bone, overall diagnostic quality (up to 50% ASIR), and subjective noise (p≤0.04), and statistically significant reductions for the trabecular bone and muscles (p≤0.03). Regardless of the radiation dose level, there were no statistically significant differences in the detection and characterization of labral tears (n=24; p=1) and cartilage lesions (n=40; p≥0.89) depending on the ASIR percentage. The use of up to 50% ASIR in hip MDCT arthrography helps to reduce radiation dose by approximately 35-60%, while maintaining diagnostic image quality comparable to that of a regular-dose protocol using FBP.

  12. Characterization of statistical prior image constrained compressed sensing (PICCS): II. Application to dose reduction.

    PubMed

    Lauzier, Pascal Theriault; Chen, Guang-Hong

    2013-02-01

    The ionizing radiation imparted to patients during computed tomography exams is raising concerns. This paper studies the performance of a scheme called dose reduction using prior image constrained compressed sensing (DR-PICCS). The purpose of this study is to characterize the effects of a statistical model of x-ray detection in the DR-PICCS framework and its impact on spatial resolution. Both numerical simulations with known ground truth and in vivo animal dataset were used in this study. In numerical simulations, a phantom was simulated with Poisson noise and with varying levels of eccentricity. Both the conventional filtered backprojection (FBP) and the PICCS algorithms were used to reconstruct images. In PICCS reconstructions, the prior image was generated using two different denoising methods: a simple Gaussian blur and a more advanced diffusion filter. Due to the lack of shift-invariance in nonlinear image reconstruction such as the one studied in this paper, the concept of local spatial resolution was used to study the sharpness of a reconstructed image. Specifically, a directional metric of image sharpness, the so-called pseudopoint spread function (pseudo-PSF), was employed to investigate local spatial resolution. In the numerical studies, the pseudo-PSF was reduced from twice the voxel width in the prior image down to less than 1.1 times the voxel width in DR-PICCS reconstructions when the statistical model was not included. At the same noise level, when statistical weighting was used, the pseudo-PSF width in DR-PICCS reconstructed images varied between 1.5 and 0.75 times the voxel width depending on the direction along which it was measured. However, this anisotropy was largely eliminated when the prior image was generated using diffusion filtering; the pseudo-PSF width was reduced to below one voxel width in that case. In the in vivo study, a fourfold improvement in CNR was achieved while qualitatively maintaining sharpness; images also had a

  13. Dose coverage calculation using a statistical shape model—applied to cervical cancer radiotherapy

    NASA Astrophysics Data System (ADS)

    Tilly, David; van de Schoot, Agustinus J. A. J.; Grusell, Erik; Bel, Arjan; Ahnesjö, Anders

    2017-05-01

    A comprehensive methodology for treatment simulation and evaluation of dose coverage probabilities is presented where a population based statistical shape model (SSM) provide samples of fraction specific patient geometry deformations. The learning data consists of vector fields from deformable image registration of repeated imaging giving intra-patient deformations which are mapped to an average patient serving as a common frame of reference. The SSM is created by extracting the most dominating eigenmodes through principal component analysis of the deformations from all patients. The sampling of a deformation is thus reduced to sampling weights for enough of the most dominating eigenmodes that describe the deformations. For the cervical cancer patient datasets in this work, we found seven eigenmodes to be sufficient to capture 90% of the variance in the deformations of the, and only three eigenmodes for stability in the simulated dose coverage probabilities. The normality assumption of the eigenmode weights was tested and found relevant for the 20 most dominating eigenmodes except for the first. Individualization of the SSM is demonstrated to be improved using two deformation samples from a new patient. The probabilistic evaluation provided additional information about the trade-offs compared to the conventional single dataset treatment planning.

  14. Dose coverage calculation using a statistical shape model-applied to cervical cancer radiotherapy.

    PubMed

    Tilly, David; van de Schoot, Agustinus J A J; Grusell, Erik; Bel, Arjan; Ahnesjö, Anders

    2017-05-21

    A comprehensive methodology for treatment simulation and evaluation of dose coverage probabilities is presented where a population based statistical shape model (SSM) provide samples of fraction specific patient geometry deformations. The learning data consists of vector fields from deformable image registration of repeated imaging giving intra-patient deformations which are mapped to an average patient serving as a common frame of reference. The SSM is created by extracting the most dominating eigenmodes through principal component analysis of the deformations from all patients. The sampling of a deformation is thus reduced to sampling weights for enough of the most dominating eigenmodes that describe the deformations. For the cervical cancer patient datasets in this work, we found seven eigenmodes to be sufficient to capture 90% of the variance in the deformations of the, and only three eigenmodes for stability in the simulated dose coverage probabilities. The normality assumption of the eigenmode weights was tested and found relevant for the 20 most dominating eigenmodes except for the first. Individualization of the SSM is demonstrated to be improved using two deformation samples from a new patient. The probabilistic evaluation provided additional information about the trade-offs compared to the conventional single dataset treatment planning.

  15. Fewer doses of HPV vaccine result in immune response similar to three-dose regimen | Division of Cancer Prevention

    Cancer.gov

    NCI scientists report that two doses of a human papillomavirus (HPV) vaccine, trademarked as Cervarix, resulted in similar serum antibody levels against two of the most carcinogenic types of HPV (16 and 18), compared to a standard three dose regimen. Among women who received only one dose, antibody levels were also high and remained stable four years after vaccination. The results suggest that fewer doses of an HPV vaccine may confer necessary long-term protection against new infection and appeared Nov. 4, 2013, in Cancer Prevention Research... |

  16. Cryptosporidium Infection Risk: Results of New Dose-Response Modeling.

    PubMed

    Messner, Michael J; Berger, Philip

    2016-10-01

    Cryptosporidium human dose-response data from seven species/isolates are used to investigate six models of varying complexity that estimate infection probability as a function of dose. Previous models attempt to explicitly account for virulence differences among C. parvum isolates, using three or six species/isolates. Four (two new) models assume species/isolate differences are insignificant and three of these (all but exponential) allow for variable human susceptibility. These three human-focused models (fractional Poisson, exponential with immunity and beta-Poisson) are relatively simple yet fit the data significantly better than the more complex isolate-focused models. Among these three, the one-parameter fractional Poisson model is the simplest but assumes that all Cryptosporidium oocysts used in the studies were capable of initiating infection. The exponential with immunity model does not require such an assumption and includes the fractional Poisson as a special case. The fractional Poisson model is an upper bound of the exponential with immunity model and applies when all oocysts are capable of initiating infection. The beta Poisson model does not allow an immune human subpopulation; thus infection probability approaches 100% as dose becomes huge. All three of these models predict significantly (>10x) greater risk at the low doses that consumers might receive if exposed through drinking water or other environmental exposure (e.g., 72% vs. 4% infection probability for a one oocyst dose) than previously predicted. This new insight into Cryptosporidium risk suggests additional inactivation and removal via treatment may be needed to meet any specified risk target, such as a suggested 10(-4) annual risk of Cryptosporidium infection.

  17. Statistical microeconomics and commodity prices: theory and empirical results.

    PubMed

    Baaquie, Belal E

    2016-01-13

    A review is made of the statistical generalization of microeconomics by Baaquie (Baaquie 2013 Phys. A 392, 4400-4416. (doi:10.1016/j.physa.2013.05.008)), where the market price of every traded commodity, at each instant of time, is considered to be an independent random variable. The dynamics of commodity market prices is given by the unequal time correlation function and is modelled by the Feynman path integral based on an action functional. The correlation functions of the model are defined using the path integral. The existence of the action functional for commodity prices that was postulated to exist in Baaquie (Baaquie 2013 Phys. A 392, 4400-4416. (doi:10.1016/j.physa.2013.05.008)) has been empirically ascertained in Baaquie et al. (Baaquie et al. 2015 Phys. A 428, 19-37. (doi:10.1016/j.physa.2015.02.030)). The model's action functionals for different commodities has been empirically determined and calibrated using the unequal time correlation functions of the market commodity prices using a perturbation expansion (Baaquie et al. 2015 Phys. A 428, 19-37. (doi:10.1016/j.physa.2015.02.030)). Nine commodities drawn from the energy, metal and grain sectors are empirically studied and their auto-correlation for up to 300 days is described by the model to an accuracy of R(2)>0.90-using only six parameters.

  18. Comparison between Pre-log and Post-log Statistical Models in Ultra-Low-Dose CT Reconstruction.

    PubMed

    Fu, Lin; Lee, Tzu-Cheng; Kim, Soo Mee; Alessio, Adam; Kinahan, Paul; Chang, Zhiqian; Sauer, Ken; Kalra, Mannudeep; De Man, Bruno

    2016-11-09

    X-ray detectors in clinical computed tomography (CT) usually operate in current-integrating mode. Their complicated signal statistics often lead to intractable likelihood functions for practical use in model-based image reconstruction (MBIR). It is therefore desirable to design simplified statistical models without losing the essential factors. Depending on whether the CT transmission data are logarithmically transformed, pre-log and post-log models are two major categories of choices in CT MBIR. Both being approximations, it remains an open question whether one model can notably improve image quality over the other on real scanners. In this study, we develop and compare several pre-log and post-log MBIR algorithms under a unified framework. Their reconstruction accuracy based on simulation and clinical datasets are evaluated. The results show that pre-log MBIR can achieve notably better quantitative accuracy than post-log MBIR in ultra-low-dose CT, although in less extreme cases, post-log MBIR with handcrafted pre-processing remains a competitive alternative. Pre-log MBIR could play a growing role in emerging ultra-low-dose CT applications.

  19. Imprecision in predicted dose from /sup 137/Cs resulting from biological variability

    SciTech Connect

    Dunning, D.E. Jr.; Schwarz, G.

    1981-01-01

    The variability of observed values of human metabolic and physiological characteristics which influence estimates of dose from ingestion of a unit of Cesium-137 activity, and the subsequent predicted total-body dose commitment is analyzed. The analysis is based on extensive literature review and statistical comparison of parameter variability, correlation and reliability. (PSB)

  20. Explanation of Two Anomalous Results in Statistical Mediation Analysis

    ERIC Educational Resources Information Center

    Fritz, Matthew S.; Taylor, Aaron B.; MacKinnon, David P.

    2012-01-01

    Previous studies of different methods of testing mediation models have consistently found two anomalous results. The first result is elevated Type I error rates for the bias-corrected and accelerated bias-corrected bootstrap tests not found in nonresampling tests or in resampling tests that did not include a bias correction. This is of special…

  1. Explanation of Two Anomalous Results in Statistical Mediation Analysis

    ERIC Educational Resources Information Center

    Fritz, Matthew S.; Taylor, Aaron B.; MacKinnon, David P.

    2012-01-01

    Previous studies of different methods of testing mediation models have consistently found two anomalous results. The first result is elevated Type I error rates for the bias-corrected and accelerated bias-corrected bootstrap tests not found in nonresampling tests or in resampling tests that did not include a bias correction. This is of special…

  2. Evaluating Replicability of Regression Results Using the Jackknife Statistic.

    ERIC Educational Resources Information Center

    Yoon, Jina

    Contrary to popular opinion, significance testing does not inform the researcher of the likelihood of the replication of results from current research findings. Result replicability has been ignored by researchers because of an overreliance on significance testing. Several alternatives have been offered to provide the researcher with more…

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

    SciTech Connect

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

    2016-05-15

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

  4. SU-E-I-86: Ultra-Low Dose Computed Tomography Attenuation Correction for Pediatric PET CT Using Adaptive Statistical Iterative Reconstruction (ASiR™)

    SciTech Connect

    Brady, S; Shulkin, B

    2015-06-15

    Purpose: To develop ultra-low dose computed tomography (CT) attenuation correction (CTAC) acquisition protocols for pediatric positron emission tomography CT (PET CT). Methods: A GE Discovery 690 PET CT hybrid scanner was used to investigate the change to quantitative PET and CT measurements when operated at ultra-low doses (10–35 mAs). CT quantitation: noise, low-contrast resolution, and CT numbers for eleven tissue substitutes were analyzed in-phantom. CT quantitation was analyzed to a reduction of 90% CTDIvol (0.39/3.64; mGy) radiation dose from baseline. To minimize noise infiltration, 100% adaptive statistical iterative reconstruction (ASiR) was used for CT reconstruction. PET images were reconstructed with the lower-dose CTAC iterations and analyzed for: maximum body weight standardized uptake value (SUVbw) of various diameter targets (range 8–37 mm), background uniformity, and spatial resolution. Radiation organ dose, as derived from patient exam size specific dose estimate (SSDE), was converted to effective dose using the standard ICRP report 103 method. Effective dose and CTAC noise magnitude were compared for 140 patient examinations (76 post-ASiR implementation) to determine relative patient population dose reduction and noise control. Results: CT numbers were constant to within 10% from the non-dose reduced CTAC image down to 90% dose reduction. No change in SUVbw, background percent uniformity, or spatial resolution for PET images reconstructed with CTAC protocols reconstructed with ASiR and down to 90% dose reduction. Patient population effective dose analysis demonstrated relative CTAC dose reductions between 62%–86% (3.2/8.3−0.9/6.2; mSv). Noise magnitude in dose-reduced patient images increased but was not statistically different from pre dose-reduced patient images. Conclusion: Using ASiR allowed for aggressive reduction in CTAC dose with no change in PET reconstructed images while maintaining sufficient image quality for co

  5. SU-F-BRB-10: A Statistical Voxel Based Normal Organ Dose Prediction Model for Coplanar and Non-Coplanar Prostate Radiotherapy

    SciTech Connect

    Tran, A; Yu, V; Nguyen, D; Woods, K; Low, D; Sheng, K

    2015-06-15

    Purpose: Knowledge learned from previous plans can be used to guide future treatment planning. Existing knowledge-based treatment planning methods study the correlation between organ geometry and dose volume histogram (DVH), which is a lossy representation of the complete dose distribution. A statistical voxel dose learning (SVDL) model was developed that includes the complete dose volume information. Its accuracy of predicting volumetric-modulated arc therapy (VMAT) and non-coplanar 4π radiotherapy was quantified. SVDL provided more isotropic dose gradients and may improve knowledge-based planning. Methods: 12 prostate SBRT patients originally treated using two full-arc VMAT techniques were re-planned with 4π using 20 intensity-modulated non-coplanar fields to a prescription dose of 40 Gy. The bladder and rectum voxels were binned based on their distances to the PTV. The dose distribution in each bin was resampled by convolving to a Gaussian kernel, resulting in 1000 data points in each bin that predicted the statistical dose information of a voxel with unknown dose in a new patient without triaging information that may be collectively important to a particular patient. We used this method to predict the DVHs, mean and max doses in a leave-one-out cross validation (LOOCV) test and compared its performance against lossy estimators including mean, median, mode, Poisson and Rayleigh of the voxelized dose distributions. Results: SVDL predicted the bladder and rectum doses more accurately than other estimators, giving mean percentile errors ranging from 13.35–19.46%, 4.81–19.47%, 22.49–28.69%, 23.35–30.5%, 21.05–53.93% for predicting mean, max dose, V20, V35, and V40 respectively, to OARs in both planning techniques. The prediction errors were generally lower for 4π than VMAT. Conclusion: By employing all dose volume information in the SVDL model, the OAR doses were more accurately predicted. 4π plans are better suited for knowledge-based planning than

  6. Statistical Differences in Time-Distance Helioseismology Results

    NASA Astrophysics Data System (ADS)

    Hess Webber, Shea A.; Pesnell, William D.; Duvall, Thomas; Cameron, Robert; Birch, A. C.

    2016-05-01

    Time-distance helioseismology studies phase correlations in solar wave modes. We use these techniques to investigate the phase differences in f-mode wave propagation within a coronal hole feature and without. We isolate the coronal hole boundary location using edge detection techniques on SDO AIA data. We then use this location information to inform the analysis of the corresponding HMI time-distance velocity tracked data product, provided by Stanford's JSOC archive. We look at time-distance results inside the coronal hole, outside the coronal hole, the coronal hole data as a whole, and an independent quiet sun region. We use Student's t-Test to evaluate the significance of the differences between the various regions.

  7. Monte Carlo dose calculations and radiobiological modelling: analysis of the effect of the statistical noise of the dose distribution on the probability of tumour control.

    PubMed

    Buffa, F M; Nahum, A E

    2000-10-01

    The aim of this work is to investigate the influence of the statistical fluctuations of Monte Carlo (MC) dose distributions on the dose volume histograms (DVHs) and radiobiological models, in particular the Poisson model for tumour control probability (tcp). The MC matrix is characterized by a mean dose in each scoring voxel, d, and a statistical error on the mean dose, sigma(d); whilst the quantities d and sigma(d) depend on many statistical and physical parameters, here we consider only their dependence on the phantom voxel size and the number of histories from the radiation source. Dose distributions from high-energy photon beams have been analysed. It has been found that the DVH broadens when increasing the statistical noise of the dose distribution, and the tcp calculation systematically underestimates the real tumour control value, defined here as the value of tumour control when the statistical error of the dose distribution tends to zero. When increasing the number of energy deposition events, either by increasing the voxel dimensions or increasing the number of histories from the source, the DVH broadening decreases and tcp converges to the 'correct' value. It is shown that the underestimation of the tcp due to the noise in the dose distribution depends on the degree of heterogeneity of the radiobiological parameters over the population; in particular this error decreases with increasing the biological heterogeneity, whereas it becomes significant in the hypothesis of a radiosensitivity assay for single patients, or for subgroups of patients. It has been found, for example, that when the voxel dimension is changed from a cube with sides of 0.5 cm to a cube with sides of 0.25 cm (with a fixed number of histories of 10(8) from the source), the systematic error in the tcp calculation is about 75% in the homogeneous hypothesis, and it decreases to a minimum value of about 15% in a case of high radiobiological heterogeneity. The possibility of using the error

  8. Bronchoscopic phototherapy at comparable dose rates: Early results

    SciTech Connect

    Pass, H.I.; Delaney, T.; Smith, P.D.; Bonner, R.; Russo, A.

    1989-05-01

    Photodynamic therapy is a recently introduced treatment for surface malignancies. Since January 1987, 10 patients with endobronchial neoplasms have had bronchoscopic photodynamic therapy at similar dose rates (400 mW/cm) for total atelectasis (2), carinal narrowing with respiratory insufficiency (2), or partial obstruction without collapse (4). Two patients underwent photodynamic therapy as a preliminary to immunotherapy. Histologies included endobronchial metastases (colon, ovary, melanoma, and sarcoma, 1 each; and renal cell, 3) and primary lung cancer (3). The 2 patients with total atelectasis had complete reexpansion after photodynamic therapy, which permitted eventual sleeve lobectomy in 1. Carinal narrowing was ameliorated in the 2 patients seen with inspiratory stridor, thereby permitting hospital discharge. Endoscopically resected fragments after photodynamic therapy exhibited avascular necrosis. These data support further controlled studies of photodynamic therapy by thoracic surgical oncologists to define its limitations as well as to improve and expand its efficacy as a palliative or surgical adjuvant.

  9. Dose-response relationships and extrapolation in toxicology - Mechanistic and statistical considerations

    EPA Science Inventory

    Controversy on toxicological dose-response relationships and low-dose extrapolation of respective risks is often the consequence of misleading data presentation, lack of differentiation between types of response variables, and diverging mechanistic interpretation. In this chapter...

  10. Dose-response relationships and extrapolation in toxicology - Mechanistic and statistical considerations

    EPA Science Inventory

    Controversy on toxicological dose-response relationships and low-dose extrapolation of respective risks is often the consequence of misleading data presentation, lack of differentiation between types of response variables, and diverging mechanistic interpretation. In this chapter...

  11. Quantitative and qualitative comparison of standard-dose and low-dose pediatric head computed tomography: a retrospective study assessing the effect of adaptive statistical iterative reconstruction.

    PubMed

    Kilic, Koray; Erbas, Gonca; Guryildirim, Melike; Konus, Oznur Leman; Arac, Mehmet; Ilgit, Erhan; Isik, Sedat

    2013-01-01

    Our aim was to assess the effect of adaptive statistical iterative reconstruction (ASIR) on pediatric head computed tomography (CT) examinations. We retrospectively reviewed 305 pediatric head CT examinations. The study population consisted of standard dose (STD, n = 152) examinations reconstructed with filtered back projection and low dose (LD, n = 153) examinations reconstructed with 30% (LD30) and 0% (LD0) ASIR. We compared groups by means of radiation dose, noise measures, and visual grading. Student t test, 1-way analysis of variance test, and Mann-Whitney U test were used for statistical analysis. The dose in the LD30 group was significantly lower (29%) than that in the STD group (P < 0.001). The noise in the white matter (P < 0.001), SNR (P < 0.001), and subjective image noise (P = 0.044) was significantly better in the STD group than those in the LD30 group. There was no significant difference between LD30 and STD groups in the sharpness (P = 0.141), diagnostic acceptability (P = 0.079), and artifacts (P = 0.750) and contrast-to-noise ratio (P = 0.718). In conclusion, we found that a blend of 30% ASIR in a 16-slice multidetector CT produces diagnostically acceptable pediatric head CT examinations with a 29% less dose.

  12. Statistical analysis plan for evaluating low‐ vs. standard‐dose alteplase in the ENhanced Control of Hypertension and Thrombolysis strokE stuDy (ENCHANTED)

    PubMed Central

    Woodward, Mark; Arima, Hisatomi; Chen, Xiaoying; Lindley, Richard I.; Wang, Xia; Chalmers, John

    2015-01-01

    Background The ENhanced Control of Hypertension And Thrombolysis strokE stuDy trial is a 2 × 2 quasi‐factorial active‐comparison, prospective, randomized, open, blinded endpoint clinical trial that is evaluating in thrombolysis‐eligible acute ischemic stroke patients whether: (1) low‐dose (0·6 mg/kg body weight) intravenous alteplase has noninferior efficacy and lower risk of symptomatic intracerebral hemorrhage compared with standard‐dose (0·9 mg/kg body weight) intravenous alteplase; and (2) early intensive blood pressure lowering (systolic target 130–140 mmHg) has superior efficacy and lower risk of any intracerebral hemorrhage compared with guideline‐recommended blood pressure control (systolic target <180 mmHg). Objective To outline in detail the predetermined statistical analysis plan for the ‘alteplase dose arm’ of the study. Methods All data collected by participating researchers will be reviewed and formally assessed. Information pertaining to the baseline characteristics of patients, their process of care, and the delivery of treatments will be classified, and for each item, appropriate descriptive statistical analyses are planned with appropriate comparisons made between randomized groups. For the trial outcomes, the most appropriate statistical comparisons to be made between groups are planned and described. Results A statistical analysis plan was developed for the results of the alteplase dose arm of the study that is transparent, available to the public, verifiable, and predetermined before completion of data collection. Conclusions We have developed a predetermined statistical analysis plan for the ENhanced Control of Hypertension And Thrombolysis strokE stuDy alteplase dose arm which is to be followed to avoid analysis bias arising from prior knowledge of the study findings. PMID:26283139

  13. An empirical approach to sufficient similarity in dose-responsiveness: Utilization of statistical distance as a similarity measure.

    EPA Science Inventory

    Using statistical equivalence testing logic and mixed model theory an approach has been developed, that extends the work of Stork et al (JABES,2008), to define sufficient similarity in dose-response for chemical mixtures containing the same chemicals with different ratios ...

  14. An empirical approach to sufficient similarity in dose-responsiveness: Utilization of statistical distance as a similarity measure.

    EPA Science Inventory

    Using statistical equivalence testing logic and mixed model theory an approach has been developed, that extends the work of Stork et al (JABES,2008), to define sufficient similarity in dose-response for chemical mixtures containing the same chemicals with different ratios ...

  15. [Accelerated partial breast irradiation using interstitial high dose rate brachytherapy: preliminary clinical and dosimetric results after 61 patients].

    PubMed

    Hannoun-Levi, J-M; Ferré, M; Raoust, I; Lallement, M; Flipo, B; Ettore, F; Marcié, S

    2008-11-01

    Among all the accelerated and partial breast irradiation (APBI) techniques, low then high dose rate, interstitial brachytherapy (HDIB) was the first to be used in this field. This study presents the preliminary clinical and dosimetric results of the APBI using HDIB, performed in Antoine Lacassagne Cancer Center of Nice. From June 2004 to March 2008, 61 patients (37 primary tumors and 24 second conservative treatments after local recurrence) presenting with T1-2 pN0 non-lobular invasive breast carcinoma, underwent lumpectomy with sentinel lymph node dissection and intraoperative tube placement for HDIB. Dose distribution analysis, using dose-volume histograms, was achieved based on a postoperative CT scan. A comparative dosimetric study was performed between optimized (O) and non-optimized (NO) dose distribution. Then, based on conformal index calculation, a novel index was proposed taking into account not only the conformity but also the homogeneity of HDIB implant. An analysis of dose gradient impact on HDIB biological equivalence dose was also conducted. Statistical analysis used T test confirmed by Wilcoxon test for cohort including less than 30 patients. The comparative dosimetric analysis between O and NO dose distributions shown that conformity indexes (conformal index, conformal number, and D90%) were significantly increased after optimization. Improving conformity leads to increasing hyperdosage volumes (V150% and V200%). A new index named conformity and homogeneity index (CHI) including V150% values, modified the conformal index. A total dose of 34 Gy, delivered through HDIB in 10 fractions over five days was biologically equivalent to 41.93 Gy assuming alpha/beta = 4 Gy and 75.76 Gy if the dose gradient was considered in the calculation. HDIB is considered as one of the best IPAS technique. HDIB allows dose distribution optimization, skin spearing and accurate clinical target volume definition. Furthermore, HDIB dose gradient could play a key role for

  16. Potential dose distributions at proposed surface radioactvity clearance levels resulting from occupational scenarios.

    SciTech Connect

    Kamboj, S.; Yu, C.; Rabovsky, J.

    2011-08-02

    The purpose of this report is to evaluate the potential dose distribution resulting from surface radioactivity, using occupational radiation exposure scenarios. The surface radioactivity clearance values considered in this analysis may ultimately replace those currently specified in the U.S. Department of Energy (DOE) requirements and guidance for radiological protection of workers, the public and the environment. The surface contamination values apply to radioactive contamination deposited on a surface (i.e., not incorporated into the interior of the material). For these calculations, the dose coefficients for intake of radionuclides were taken from ICRP Publication 68 (ICRP 1994), and external exposure dose coefficients were taken from the compact disc (CD) that accompanied Federal Guidance Report (FGR) 13 (Eckerman et al. 1999). The ICRP Publication 68 dose coefficients were based on ICRP Publication 60 (ICRP 1990) and were used specifically for worker dose calculations. The calculated dose in this analysis is the 'effective dose' (ED), rather than the 'effective dose equivalent' (EDE).

  17. Adaptive Statistical Iterative Reconstruction-V Versus Adaptive Statistical Iterative Reconstruction: Impact on Dose Reduction and Image Quality in Body Computed Tomography.

    PubMed

    Gatti, Marco; Marchisio, Filippo; Fronda, Marco; Rampado, Osvaldo; Faletti, Riccardo; Bergamasco, Laura; Ropolo, Roberto; Fonio, Paolo

    2017-09-20

    The aim of this study was to evaluate the impact on dose reduction and image quality of the new iterative reconstruction technique: adaptive statistical iterative reconstruction (ASIR-V). Fifty consecutive oncologic patients acted as case controls undergoing during their follow-up a computed tomography scan both with ASIR and ASIR-V. Each study was analyzed in a double-blinded fashion by 2 radiologists. Both quantitative and qualitative analyses of image quality were conducted. Computed tomography scanner radiation output was 38% (29%-45%) lower (P < 0.0001) for the ASIR-V examinations than for the ASIR ones. The quantitative image noise was significantly lower (P < 0.0001) for ASIR-V. Adaptive statistical iterative reconstruction-V had a higher performance for the subjective image noise (P = 0.01 for 5 mm and P = 0.009 for 1.25 mm), the other parameters (image sharpness, diagnostic acceptability, and overall image quality) being similar (P > 0.05). Adaptive statistical iterative reconstruction-V is a new iterative reconstruction technique that has the potential to provide image quality equal to or greater than ASIR, with a dose reduction around 40%.

  18. Current Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

    NASA Technical Reports Server (NTRS)

    Cochran, Donna J.; Kniffin, Scott D.; LaBel, Kenneth A.; OBryan, Martha V.; Reed, Robert A.; Ladbury, Ray L.; Howard, James W., Jr.; Poivey, Christian; Buchner, Stephen P.; Marshall, Cheryl J.

    2004-01-01

    We present data on the vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage. Devices tested include optoelectronics, digital, analog, linear bipolar devices, hybrid devices, Analog-to-Digital Converters (ADCs), and Digital-to-Analog Converters (DACS), among others.

  19. Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

    NASA Technical Reports Server (NTRS)

    Cochran, Donna J.; Kniffin, Scott D.; LaBel, Kenneth A.; OBryan, Martha V.; Reed, Robert A.; Ladbury, Ray L.; Howard, James W., Jr.; Poivey, Christian; Buchner, Stephen P.; Marshall, Cheryl J.

    2003-01-01

    We present data on the vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage. Devices tested include optoelectronics, digital, analog, linear bipolar devices, hybrid devices, Analog-to-Digital Converters (ADCs), and Digital-to-Analog Converters (DACs), among others.

  20. Recent Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

    NASA Technical Reports Server (NTRS)

    Cochran, Donna J.; Buchner, Stephen P.; Irwin, Tim L.; LaBel, Kenneth A.; Marshall, Cheryl J.; Reed, Robert A.; Sanders, Anthony B.; Hawkins, Donald K.; Flanigan, Ryan J.; Cox, Stephen R.

    2005-01-01

    We present data on the vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage. Devices tested include optoelectronics, digital, analog, linear bipolar devices, hybrid devices, Analog-to- Digital Converters (ADCs), and Digital-to-Analog Converters (DACs), among others. T

  1. Recommendations for describing statistical studies and results in general readership science and engineering journals.

    PubMed

    Gardenier, John S

    2012-12-01

    This paper recommends how authors of statistical studies can communicate to general audiences fully, clearly, and comfortably. The studies may use statistical methods to explore issues in science, engineering, and society or they may address issues in statistics specifically. In either case, readers without explicit statistical training should have no problem understanding the issues, the methods, or the results at a non-technical level. The arguments for those results should be clear, logical, and persuasive. This paper also provides advice for editors of general journals on selecting high quality statistical articles without the need for exceptional work or expense. Finally, readers are also advised to watch out for some common errors or misuses of statistics that can be detected without a technical statistical background.

  2. Dose-Volume Parameters of the Corpora Cavernosa Do Not Correlate With Erectile Dysfunction After External Beam Radiotherapy for Prostate Cancer: Results From a Dose-Escalation Trial

    SciTech Connect

    Wielen, Gerard J. van der Hoogeman, Mischa S.; Dohle, Gert R.; Putten, Wim L.J. van; Incrocci, Luca

    2008-07-01

    Purpose: To analyze the correlation between dose-volume parameters of the corpora cavernosa and erectile dysfunction (ED) after external beam radiotherapy (EBRT) for prostate cancer. Methods and Materials: Between June 1997 and February 2003, a randomized dose-escalation trial comparing 68 Gy and 78 Gy was conducted. Patients at our institute were asked to participate in an additional part of the trial evaluating sexual function. After exclusion of patients with less than 2 years of follow-up, ED at baseline, or treatment with hormonal therapy, 96 patients were eligible. The proximal corpora cavernosa (crura), the superiormost 1-cm segment of the crura, and the penile bulb were contoured on the planning computed tomography scan and dose-volume parameters were calculated. Results: Two years after EBRT, 35 of the 96 patients had developed ED. No statistically significant correlations between ED 2 years after EBRT and dose-volume parameters of the crura, the superiormost 1-cm segment of the crura, or the penile bulb were found. The few patients using potency aids typically indicated to have ED. Conclusion: No correlation was found between ED after EBRT for prostate cancer and radiation dose to the crura or penile bulb. The present study is the largest study evaluating the correlation between ED and radiation dose to the corpora cavernosa after EBRT for prostate cancer. Until there is clear evidence that sparing the penile bulb or crura will reduce ED after EBRT, we advise to be careful in sparing these structures, especially when this involves reducing treatment margins.

  3. Crop identification technology assessment for remote sensing. (CITARS) Volume 9: Statistical analysis of results

    NASA Technical Reports Server (NTRS)

    Davis, B. J.; Feiveson, A. H.

    1975-01-01

    Results are presented of CITARS data processing in raw form. Tables of descriptive statistics are given along with descriptions and results of inferential analyses. The inferential results are organized by questions which CITARS was designed to answer.

  4. A method of estimating conceptus doses resulting from multidetector CT examinations during all stages of gestation

    SciTech Connect

    Damilakis, John; Tzedakis, Antonis; Perisinakis, Kostas; Papadakis, Antonios E.

    2010-12-15

    Purpose: Current methods for the estimation of conceptus dose from multidetector CT (MDCT) examinations performed on the mother provide dose data for typical protocols with a fixed scan length. However, modified low-dose imaging protocols are frequently used during pregnancy. The purpose of the current study was to develop a method for the estimation of conceptus dose from any MDCT examination of the trunk performed during all stages of gestation. Methods: The Monte Carlo N-Particle (MCNP) radiation transport code was employed in this study to model the Siemens Sensation 16 and Sensation 64 MDCT scanners. Four mathematical phantoms were used, simulating women at 0, 3, 6, and 9 months of gestation. The contribution to the conceptus dose from single simulated scans was obtained at various positions across the phantoms. To investigate the effect of maternal body size and conceptus depth on conceptus dose, phantoms of different sizes were produced by adding layers of adipose tissue around the trunk of the mathematical phantoms. To verify MCNP results, conceptus dose measurements were carried out by means of three physical anthropomorphic phantoms, simulating pregnancy at 0, 3, and 6 months of gestation and thermoluminescence dosimetry (TLD) crystals. Results: The results consist of Monte Carlo-generated normalized conceptus dose coefficients for single scans across the four mathematical phantoms. These coefficients were defined as the conceptus dose contribution from a single scan divided by the CTDI free-in-air measured with identical scanning parameters. Data have been produced to take into account the effect of maternal body size and conceptus position variations on conceptus dose. Conceptus doses measured with TLD crystals showed a difference of up to 19% compared to those estimated by mathematical simulations. Conclusions: Estimation of conceptus doses from MDCT examinations of the trunk performed on pregnant patients during all stages of gestation can be made

  5. Low dose alpha interferon therapy can be effective in chronic active hepatitis C. Results of a multicentre, randomised trial.

    PubMed Central

    Sánchez-Tapias, J M; Forns, X; Ampurdanés, S; Titó, L; Planas, R; Viver, J M; Acero, D; Torres, M; Mas, P; Morillas, R; Forné, M; Espinós, J; Llovet, J M; Costa, J; Olmedo, E; López-Labrador, F X; Jiménez de Anta, M T; Rodés, J

    1996-01-01

    BACKGROUND--There is some controversy concerning the efficacy of low dose alpha interferon therapy in chronic hepatitis C. AIMS--To evaluate the effectiveness of treatment with low doses of alpha interferon in chronic hepatitis C. PATIENTS--One hundred and forty one patients with anti-HCV positive chronic active hepatitis C from six hospitals were enrolled in the study. METHODS--Patients were randomised to treatment with 5 MU (group A) or 1.5 MU (group B) injections. The dose was reduced in responders from group A or increased in non-responders from group B to maintain treatment with the minimal effective dose. Patients were treated for 48 weeks and followed up for 24 additional weeks with no treatment. Normalisation of alanine aminotransferase (ALT) was used to evaluate response. RESULTS--A sustained response was seen in eight patients from group A (12%) and in 15 (21%) from group B. This difference was not statistically significant. Increasing the dose of interferon led to sustained response in only five of 58 patients (9%) from group B who did not respond to 1.5 MU injections. In contrast, 15 of 21 patients (71%) in whom ALT remained normal with 1.5 MU injections developed a sustained response. By multivariate analysis sustained response seemed associated with young age and was more frequent in patients with genotype 3 HCV infection. Sustained response was preceded by a rapid normalisation of ALT and was inversely related to the amount of alpha interferon necessary to maintain ALT at low values during treatment. CONCLUSIONS--Some patients with chronic hepatitis C are very sensitive to alpha interferon and can be successfully treated with low doses. Treatment with higher doses may be effective in a minority of patients who do not respond to low doses. PMID:8707096

  6. Can use of adaptive statistical iterative reconstruction reduce radiation dose in unenhanced head CT? An analysis of qualitative and quantitative image quality

    PubMed Central

    Heggen, Kristin Livelten; Pedersen, Hans Kristian; Andersen, Hilde Kjernlie; Martinsen, Anne Catrine T

    2016-01-01

    Background Iterative reconstruction can reduce image noise and thereby facilitate dose reduction. Purpose To evaluate qualitative and quantitative image quality for full dose and dose reduced head computed tomography (CT) protocols reconstructed using filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR). Material and Methods Fourteen patients undergoing follow-up head CT were included. All patients underwent full dose (FD) exam and subsequent 15% dose reduced (DR) exam, reconstructed using FBP and 30% ASIR. Qualitative image quality was assessed using visual grading characteristics. Quantitative image quality was assessed using ROI measurements in cerebrospinal fluid (CSF), white matter, peripheral and central gray matter. Additionally, quantitative image quality was measured in Catphan and vendor’s water phantom. Results There was no significant difference in qualitative image quality between FD FBP and DR ASIR. Comparing same scan FBP versus ASIR, a noise reduction of 28.6% in CSF and between −3.7 and 3.5% in brain parenchyma was observed. Comparing FD FBP versus DR ASIR, a noise reduction of 25.7% in CSF, and −7.5 and 6.3% in brain parenchyma was observed. Image contrast increased in ASIR reconstructions. Contrast-to-noise ratio was improved in DR ASIR compared to FD FBP. In phantoms, noise reduction was in the range of 3 to 28% with image content. Conclusion There was no significant difference in qualitative image quality between full dose FBP and dose reduced ASIR. CNR improved in DR ASIR compared to FD FBP mostly due to increased contrast, not reduced noise. Therefore, we recommend using caution if reducing dose and applying ASIR to maintain image quality. PMID:27583169

  7. Application of a statistical software package for analysis of large patient dose data sets obtained from RIS.

    PubMed

    Fazakerley, J; Charnock, P; Wilde, R; Jones, R; Ward, M

    2010-01-01

    For the purpose of patient dose audit, clinical audit and radiology workload analysis, data from Radiology Information Systems (RIS) at many hospitals are collected using a database and the analysis was automated using a statistical package and Visual Basic coding. The database is a Structured Query Language database, which can be queried using an off-the-shelf statistical package, Statistica. Macros were created to automatically format the data to a consistent format between different hospitals ready for analysis. These macros can also be used to automate further analysis such as detailing mean kV, mAs and entrance surface dose per room and per gender. Standard deviation and standard error of the mean are also generated. Graphs can also be generated to illustrate the trends in doses between different variables such as room and gender. Collectively, this information can be used to generate a report. A process that once could take up to 1 d to complete now takes around 1 h. A major benefit in providing the service to hospital trusts is that less resource is now required to report on RIS data, making the possibility of continuous dose audit more likely. Time that was spent on sorting through data can now be spent on improving the analysis to provide benefit to the customer. Using data sets from RIS is a good way to perform dose audits as the huge numbers of data available provide the bases for very accurate analysis. Using macros written in Statistica Visual Basic has helped sort and consistently analyse these data. Being able to analyse by exposure factors has provided a more detailed report to the customer.

  8. 42 CFR 82.25 - When will NIOSH report dose reconstruction results, and to whom?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false When will NIOSH report dose reconstruction results, and to whom? 82.25 Section 82.25 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES METHODS FOR CONDUCTING DOSE...

  9. Results of monte carlo calculations of neutron spectra and doses outside the BDMS shielding

    SciTech Connect

    Radev, R P; Hall, J M

    2000-10-16

    A set of Monte Carlo calculations of the neutron dose rates and neutron spectra outside Blend Down Monitoring System (BDMS) shielding were performed with U.S. and Russian neutron fluence-to-dose conversion coefficients. The purpose of these calculations was to facilitate the proper interpretation of the dose rate measurements from rem meters outside the BDMS shielding. An accurate determination of the dose rate is of particular interest so that dose rate can be compared with the applicable regulatory limit. The calculations show that the neutrons outside the BDMS shielding are significantly reduced in energy, i.e. the spectrum is shifted (moderated) towards the lower energies and contains significantly larger amount of neutrons in the energy range below 100 keV. The result of these calculations indicates that the dose measurement for the BDMS neutrons is overestimated from 25% to 55% depending on the location around BDMS when using either Russian or U.S. dose conversion coefficients. For an accurate neutron dose determination the application of an appropriate correcting factor to the neutron dose measurement is necessary.

  10. Biological efficacy of low versus medium dose aspirin after coronary surgery: results from a randomized trial [NCT00262275

    PubMed Central

    Lim, Eric; Cornelissen, Jacqueline; Routledge, Tom; Ali, Ayyaz; Kirtland, Stephen; Sharples, Linda; Sheridan, Kate; Bellm, Sarah; Munday, Helen; Large, Stephen

    2006-01-01

    Background The beneficial effect of aspirin after coronary surgery is established; however, a recent study reported the inability of low doses (100 mg) to inhibit postoperative platelet function. We conducted a double-blind randomised trial to establish the efficacy of low dose aspirin and to compare it against medium dose aspirin. Methods Patients undergoing coronary surgery were invited to participate and consenting patients were randomised to 100 mg or 325 mg of aspirin daily for 5 days. Our primary outcome was the difference in platelet aggregation (day 5 – baseline) using 1 μg/ml of collagen. Secondary outcomes were differences in EC50 of collagen, ADP and epinephrine (assessed using the technique of Born). Results From September 2002 to April 2004, 72 patients were randomised; 3 patients discontinued, leaving 35 and 34 in the low and medium dose aspirin arms respectively. The mean aggregation (using 1.1 μg/ml of collagen) was reduced in both the medium and low dose aspirin arms by 37% and 36% respectively. The baseline adjusted difference (low – medium) was 6% (95% CI -3 to 14; p = 0.19). The directions of the results for the differences in EC50 (low – medium) were consistent for collagen, ADP and epinephrine at -0.07 (-0.53 to 0.40), -0.08 (-0.28 to 0.11) and -4.41 (-10.56 to 1.72) respectively, but none were statistically significant. Conclusion Contrary to recent findings, low dose aspirin is effective and medium dose aspirin did not prove superior for inhibiting platelet aggregation after coronary surgery. PMID:16716214

  11. Patient doses in CT examinations in 18 countries: initial results from International Atomic Energy Agency projects.

    PubMed

    Muhogora, W E; Ahmed, N A; Beganovic, A; Benider, A; Ciraj-Bjelac, O; Gershan, V; Gershkevitsh, E; Grupetta, E; Kharita, M H; Manatrakul, N; Milakovic, M; Ohno, K; Ben Omrane, L; Ptacek, J; Schandorf, C; Shabaan, M S; Stoyanov, D; Toutaoui, N; Wambani, J S; Rehani, M M

    2009-09-01

    The purpose of this prospective study at 73 facilities in 18 countries in Africa, Asia and Eastern Europe was to investigate if the CT doses to adult patients in developing countries are higher than international standards. The dose assessment was performed in terms of weighted computed tomography dose index (CTDIw) and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. Except in one case, the mean CTDIw values were below diagnostic reference level (DRL) while for DLP, 17 % of situations were above DRLs. The resulting CT images were of adequate quality for diagnosis. The CTDIw and DLP data presented herein are largely similar to those from two recent national surveys. The study has shown a stronger need to create awareness and training of radiology personnel as well as monitoring of radiation doses in many developing countries so as to conform to the ALARA principle.

  12. Estimation of the committed radiation dose resulting from gamma radionuclides ingested with food.

    PubMed

    Godyń, Piotr; Dołhańczuk-Śródka, Agnieszka; Ziembik, Zbigniew; Moliszewska, Ewa

    The objective of the study was to estimate the value of the radiation dose absorbed in consequence of consumption of popular food products for individual age groups. Potatoes, corn and sugar beet were selected for the study. Edible parts of these plants were collected in experimental fields of the KWS Lochów Polska Sp. z o.o. seeding company in Kondratowice (Poland). On the basis of the obtained study results, it can be stated that in consequence of consumption of the selected food products, people may receive increased doses from both natural and artificial radioactive isotopes. The doses calculated for several age groups do not show any health hazards in consequence of consumption of the tested food. One of the determined radionuclides was (137)Cs; however, its presence in the absorbed dose is lower than the doses from natural radioactive isotopes, in particular (40)K.

  13. Test Results of Total Ionizing Dose Conducted at the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Rivas, Rosa M.; Johnston, Allan H.; Miyahira, Tetsuo F.; Rax, Bernard G.; Wiedeman, Michael D.

    2004-01-01

    This paper reports recent Total Ionizing Dose (TID) test results obtained at JPL. Several device samples were analyzed exhibiting significant failure levels and ELDRS effects under biased and unbiased condition.

  14. Test Results of Total Ionizing Dose Conducted at the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Rivas, Rosa M.; Johnston, Allan H.; Miyahira, Tetsuo F.; Rax, Bernard G.; Wiedeman, Michael D.

    2004-01-01

    This paper reports recent Total Ionizing Dose (TID) test results obtained at JPL. Several device samples were analyzed exhibiting significant failure levels and ELDRS effects under biased and unbiased condition.

  15. Calculating the peak skin dose resulting from fluoroscopically guided interventions. Part I: Methods.

    PubMed

    Jones, A Kyle; Pasciak, Alexander S

    2011-11-15

    While direct measurement of the peak skin dose resulting from a fluoroscopically-guided procedure is possible, the decision must be made a priori at additional cost and time. It is most often the case that the need for accurate knowledge of the peak skin dose is realized only after a procedure has been completed, or after a suspected reaction has been discovered. Part I of this review article discusses methods for calculating the peak skin dose across a range of clinical scenarios. In some cases, a wealth of data are available, while in other cases few data are available and additional data must be measured in order to estimate the peak skin dose. Data may be gathered from a dose report, the DICOM headers of images, or from staff and physician interviews. After data are gathered, specific steps must be followed to convert dose metrics, such as the reference point air kerma (K(a,r)) or the kerma area product (KAP), into peak skin dose. These steps require knowledge of other related factors, such as the f-factor and the backscatter factor, tables of which are provided in this manuscript. Sources of error and the impact of these errors on the accuracy of the final estimate of the peak skin dose are discussed.

  16. Dosimetric study of the effective doses resulting during dental X-ray and panoramic radiography

    NASA Astrophysics Data System (ADS)

    Shousha, Hany A.; Abd-El Hafez, A. I.; Ahmad, Fawzia

    2011-01-01

    The panoramic image is one of the most commonly used radiographic examinations in dentistry, owing to its low dose and large area for evaluation, including bone and teeth in the same image. Although digital images are usually reported to deliver a lower radiation dose to the patient, conventional images are still available, especially in countries where digital systems are not widely economically available. Dentists should weigh the benefits of dental radiographs against the consequences of increasing a patient's exposure to radiation, the effects of which accumulate from multiple sources over time. The "as low as reasonably achievable" principle should be followed to minimize the exposure to radiation. The purpose of this investigation is to measure the absorbed radiation doses at 12 anatomical sites of a Rando-phantom and calculate the effective doses result from a full-mouth survey and panoramic radiography. Organ-absorbed doses are measured using thermoluminescent dosimeters (TLD 100) and effective organ doses (μ Sv) are estimated according to the International Commission on Radiological Protection in 2007. The total effective dose results from the panoramic imaging system have so far been below those obtained using the full-mouth survey technique used in intra-oral radiographic examination.

  17. The effective dose result of 18F-FDG PET-CT paediatric patients

    NASA Astrophysics Data System (ADS)

    Hussin, D.; Said, M. A.; Ali, N. S.; Tajuddin, A. A.; Zainon, R.

    2017-05-01

    Paediatric patient received high exposure from both CT and PET examination. Automatic Exposure Control (AEC) is important in CT dose reduction. This study aimed to compare the effective dose obtained from PET-CT scanner with and without the use of AEC function. In this study, 68 patients underwent PET-CT examination without the use of AEC function, while 25 patients used the AEC function during the examination. Patients involved in this study were between 2 to 15 years old with varies of malignancies and epilepsy diseases. The effective dose obtained from PET and CT examinations was calculated based on recommendation from International Commission on Radiological Protection (ICRP) Publication 106 and ICRP publication 102. The outcome of this study shows that the radiation dose was reduced up to 20% with the use of AEC function. The mean average of effective dose result obtained from PET and CT examinations without the use of AEC and AEC function were found to be as 6.67 mSv, 6.77 mSv, 6.03mSv and 4.96 mSv respectively. Where total effective dose result of PET-CT with non-AEC and AEC were found to be 13.44 mSv and 10.99 mSv respectively. Conclusion of this study is, the installation of AEC function in PET-CT machine does play important role in CT dose reduction especially for paediatric patient.

  18. Statistical simulations to estimate motion-inclusive dose-volume histograms for prediction of rectal morbidity following radiotherapy

    PubMed Central

    THOR, MARIA; APTE, ADITYA; DEASY, JOSEPH O.; MUREN, LUDVIG PAUL

    2016-01-01

    Background and purpose Internal organ motion over a course of radiotherapy (RT) leads to uncertainties in the actual delivered dose distributions. In studies predicting RT morbidity, the single estimate of the delivered dose provided by the treatment planning computed tomography (pCT) is typically assumed to be representative of the dose distribution throughout the course of RT. In this paper, a simple model for describing organ motion is introduced, and is associated to late rectal morbidity data, with the aim of improving morbidity prediction. Material and methods Organ motion was described by normally distributed translational motion, with its magnitude characterised by the standard deviation (SD) of this distribution. Simulations of both isotropic and anisotropic (anterior-posterior only) motion patterns were performed, as were random, systematic or combined random and systematic motion. The associations between late rectal morbidity and motion-inclusive delivered dose-volume histograms (dDVHs) were quantified using Spearman's rank correlation coefficient (Rs) in a series of 232 prostate cancer patients, and were compared to the associations obtained with the static/planned DVH (pDVH). Results For both isotropic and anisotropic motion, different associations with rectal morbidity were seen with the dDVHs relative to the pDVHs. The differences were most pronounced in the mid-dose region (40–60 Gy). The associations were dependent on the applied motion patterns, with the strongest association with morbidity obtained by applying random motion with an SD in the range 0.2–0.8 cm. Conclusion In this study we have introduced a simple model for describing organ motion occurring during RT. Differing and, for some cases, stronger dose-volume dependencies were found between the motion-inclusive dose distributions and rectal morbidity as compared to the associations with the planned dose distributions. This indicates that rectal organ motion during RT influences the

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

    SciTech Connect

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

    2016-09-01

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

  20. A survey of patient doses from conventional diagnostic radiology examinations: first results from Serbia and Montenegro.

    PubMed

    Ciraj, Olivera; Kosutic, Dusko; Kovacevic, Milojko; Markovic, Srpko

    Diagnostic reference levels provide framework to reduce variability. The aim of this study is to establish, for the first time, a baseline for national diagnostic reference levels in Serbia and Montenegro for the most common X-ray examination types. Measurements of patient dose using kerma-area product meter and entrance surface air kerma assessment were performed on at least ten patients for each examination type, in each of 16 randomly selected hospitals in Serbia and Montenegro, so that a total of 3,026 procedures for nine different examination categories were included in the survey. Exposure settings and individual data were recorded for each patient. Mean, median and third quartile values of patient doses are reported. Results have shown wide variation of mean hospital doses, with factor of four for barium enema to 23 for thoracic spine radiography. Entrance surface air kerma were compared with previously published diagnostic reference levels (DRL) proposed by Commission of European Communities (CEC). Doses for all studied examination types except chest radiography were within European DRL. The reasons for dose variation are discussed. Survey data are aimed to help in development of an on-going national quality assurance and quality control programme in diagnostic radiology. The findings emphasize the importance of regular patient dose measurement to ensure that patient doses are kept as low as reasonable achievable.

  1. Online training on the safe use of fluoroscopy can result in a significant decrease in patient dose.

    PubMed

    Frederick-Dyer, Katherine C; Faulkner, Austin R; Chang, Ted T; Heidel, R Eric; Pasciak, Alexander S

    2013-10-01

    Concerns over medical radiation exposure have received national press in recent years, and training in the appropriate use of radiation has become an essential component of every radiology residency program. Appropriate training is particularly important in fluoroscopy because it is commonly used by inexperienced radiology residents and has the potential to impart relatively high patient radiation doses. In an effort to minimize the radiation doses received by patients, our institution has recently initiated an online training program in the safe use of fluoroscopy. This course is required and must be completed by new radiology residents before their first fluoroscopy rotation. The goal of this study was to determine if the use of an online course in the safe use of fluoroscopy could result in decreased patient dose without affecting diagnostic quality. Four years of retrospective procedural data for residents performing gastrointestinal and genitourinary fluoroscopic procedures without specialized training were reviewed. Incoming residents took an American Medical Association-accredited online training program in the safe use of fluoroscopy the week before their first fluoroscopy rotation. Patient dose and diagnostic quality data, inferred from the frequency of attending physician intervention necessary to complete the procedure, were collected for all exams performed by the new group of residents after completion of the training course. This was then compared to data from prior classes and stratified by procedure type. Statistically significant reductions in both average fluoroscopy time (FT) or dose-area-product (DAP) were found for many of the fluoroscopic procedures performed by residents who participated in the online fluoroscopy training program. Specifically, statistically significant reductions in FT for barium enema, cystogram, defecogram, and esophagram procedures (P < .001) were found. Esophagram and upper gastrointestinal studies were completed with a

  2. A graphical user interface (GUI) toolkit for the calculation of three-dimensional (3D) multi-phase biological effective dose (BED) distributions including statistical analyses.

    PubMed

    Kauweloa, Kevin I; Gutierrez, Alonso N; Stathakis, Sotirios; Papanikolaou, Niko; Mavroidis, Panayiotis

    2016-07-01

    A toolkit has been developed for calculating the 3-dimensional biological effective dose (BED) distributions in multi-phase, external beam radiotherapy treatments such as those applied in liver stereotactic body radiation therapy (SBRT) and in multi-prescription treatments. This toolkit also provides a wide range of statistical results related to dose and BED distributions. MATLAB 2010a, version 7.10 was used to create this GUI toolkit. The input data consist of the dose distribution matrices, organ contour coordinates, and treatment planning parameters from the treatment planning system (TPS). The toolkit has the capability of calculating the multi-phase BED distributions using different formulas (denoted as true and approximate). Following the calculations of the BED distributions, the dose and BED distributions can be viewed in different projections (e.g. coronal, sagittal and transverse). The different elements of this toolkit are presented and the important steps for the execution of its calculations are illustrated. The toolkit is applied on brain, head & neck and prostate cancer patients, who received primary and boost phases in order to demonstrate its capability in calculating BED distributions, as well as measuring the inaccuracy and imprecision of the approximate BED distributions. Finally, the clinical situations in which the use of the present toolkit would have a significant clinical impact are indicated. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Study designs, use of statistical tests, and statistical analysis software choice in 2015: Results from two Pakistani monthly Medline indexed journals.

    PubMed

    Shaikh, Masood Ali

    2017-09-01

    Assessment of research articles in terms of study designs used, statistical tests applied and the use of statistical analysis programmes help determine research activity profile and trends in the country. In this descriptive study, all original articles published by Journal of Pakistan Medical Association (JPMA) and Journal of the College of Physicians and Surgeons Pakistan (JCPSP), in the year 2015 were reviewed in terms of study designs used, application of statistical tests, and the use of statistical analysis programmes. JPMA and JCPSP published 192 and 128 original articles, respectively, in the year 2015. Results of this study indicate that cross-sectional study design, bivariate inferential statistical analysis entailing comparison between two variables/groups, and use of statistical software programme SPSS to be the most common study design, inferential statistical analysis, and statistical analysis software programmes, respectively. These results echo previously published assessment of these two journals for the year 2014.

  4. A Bayesian analysis of uncertainties on lung doses resulting from occupational exposures to uranium.

    PubMed

    Puncher, M; Birchall, A; Bull, R K

    2013-09-01

    In a recent epidemiological study, Bayesian estimates of lung doses were calculated in order to determine a possible association between lung dose and lung cancer incidence resulting from occupational exposures to uranium. These calculations, which produce probability distributions of doses, used the human respiratory tract model (HRTM) published by the International Commission on Radiological Protection (ICRP) with a revised particle transport clearance model. In addition to the Bayesian analyses, point estimates (PEs) of doses were also provided for that study using the existing HRTM as it is described in ICRP Publication 66. The PEs are to be used in a preliminary analysis of risk. To explain the differences between the PEs and Bayesian analysis, in this paper the methodology was applied to former UK nuclear workers who constituted a subset of the study cohort. The resulting probability distributions of lung doses calculated using the Bayesian methodology were compared with the PEs obtained for each worker. Mean posterior lung doses were on average 8-fold higher than PEs and the uncertainties on doses varied over a wide range, being greater than two orders of magnitude for some lung tissues. It is shown that it is the prior distributions of the parameters describing absorption from the lungs to blood that are responsible for the large difference between posterior mean doses and PEs. Furthermore, it is the large prior uncertainties on these parameters that are mainly responsible for the large uncertainties on lung doses. It is concluded that accurate determination of the chemical form of inhaled uranium, as well as the absorption parameter values for these materials, is important for obtaining unbiased estimates of lung doses from occupational exposures to uranium for epidemiological studies. Finally, it should be noted that the inferences regarding the PEs described here apply only to the assessments of cases provided for the epidemiological study, where central

  5. Interpreting Statistical Significance Test Results: A Proposed New "What If" Method.

    ERIC Educational Resources Information Center

    Kieffer, Kevin M.; Thompson, Bruce

    As the 1994 publication manual of the American Psychological Association emphasized, "p" values are affected by sample size. As a result, it can be helpful to interpret the results of statistical significant tests in a sample size context by conducting so-called "what if" analyses. However, these methods can be inaccurate…

  6. Almost all articles on cancer prognostic markers report statistically significant results.

    PubMed

    Kyzas, Panayiotis A; Denaxa-Kyza, Despina; Ioannidis, John P A

    2007-11-01

    We aimed to understand the extent of the pursuit for statistically significant results in the prognostic literature of cancer. We evaluated 340 articles included in prognostic marker meta-analyses (Database 1) and 1575 articles on cancer prognostic markers published in 2005 (Database 2). For each article, we examined whether the abstract reported any statistically significant prognostic effect for any marker and any outcome ('positive' articles). 'Negative' articles were further examined for statements made by the investigators to overcome the absence of prognostic statistical significance. We also examined how the articles of Database 1 had presented the relative risks that were included in the respective meta-analyses. 'Positive' prognostic articles comprised 90.6% and 95.8% in Databases 1 and 2, respectively. Most of the 'negative' prognostic articles claimed significance for other analyses, expanded on non-significant trends or offered apologies that were occasionally remote from the original study aims. Only five articles in Database 1 (1.5%) and 21 in Database 2 (1.3%) were fully 'negative' for all presented results in the abstract and without efforts to expand on non-significant trends or to defend the importance of the marker with other arguments. Of the statistically non-significant relative risks in the meta-analyses, 25% had been presented as statistically significant in the primary papers using different analyses compared with the respective meta-analysis. We conclude that almost all articles on cancer prognostic marker studies highlight some statistically significant results. Under strong reporting bias, statistical significance loses its discriminating ability for the importance of prognostic markers.

  7. Up-dosing with bilastine results in improved effectiveness in cold contact urticaria

    PubMed Central

    Krause, K; Spohr, A; Zuberbier, T; Church, M K; Maurer, M

    2013-01-01

    Background Cold contact urticaria (CCU) is characterized by itchy wheal and flare responses due to the release of histamine and other pro-inflammatory mediators after exposure to cold. The treatment of choice is nonsedating antihistamines, dosages of which may be increased up to fourfold if standard doses are ineffective. Here, we assess the effects of a standard 20 mg dose and up-dosing to 40 and 80 mg of bilastine in reducing the symptoms of CCU and inflammatory mediator release following cold challenge. Methods Twenty patients with CCU were included in this randomized, crossover, double-blind, placebo-controlled 12-week study. They received placebo, 20, 40 or 80 mg of bilastine daily each for 7 days with 14-day washout periods. The primary readout was change in critical temperature thresholds (CTT). Secondary readouts were changes in pruritus, levels of histamine IL-6, IL-8 and TNF-α collected by skin microdialysis and safety and tolerability of bilastine. Results Bilastine 20 mg was highly effective (P < 0.0001) in reducing CTT. Up-dosing to 80 mg significantly (P < 0.04) increased its effectiveness. At this dose, 19 of 20 (95%) patients responded to treatment, with 12 of 20 (60%) becoming symptom free. Only one patient was refractory to treatment. Microdialysis levels of histamine, IL-6 and IL-8 assessed 1–3 h after cold challenge were significantly (P < 0.05) decreased following up-dosing with 80 mg bilastine. Bilastine treat-ment was well tolerated without evidence of increased sedation with dose escala-tion. Conclusions Bilastine was effective in reducing the symptoms of patients with CCU. Increased efficacy of bilastine with fourfold up-dosing was without sedation and supports urticaria treatment guidelines. PMID:23742030

  8. Impact of the Adaptive Statistical Iterative Reconstruction Technique on Radiation Dose and Image Quality in Bone SPECT/CT.

    PubMed

    Sibille, Louis; Chambert, Benjamin; Alonso, Sandrine; Barrau, Corinne; D'Estanque, Emmanuel; Al Tabaa, Yassine; Collombier, Laurent; Demattei, Christophe; Kotzki, Pierre-Olivier; Boudousq, Vincent

    2016-07-01

    The purpose of this study was to compare a routine bone SPECT/CT protocol using CT reconstructed with filtered backprojection (FBP) with an optimized protocol using low-dose CT images reconstructed with adaptive statistical iterative reconstruction (ASiR). In this prospective study, enrolled patients underwent bone SPECT/CT, with 1 SPECT acquisition followed by 2 randomized CT acquisitions: FBP CT (FBP; noise index, 25) and ASiR CT (70% ASiR; noise index, 40). The image quality of both attenuation-corrected SPECT and CT images was visually (5-point Likert scale, 2 interpreters) and quantitatively (contrast ratio [CR] and signal-to-noise ratio [SNR]) estimated. The CT dose index volume, dose-length product, and effective dose were compared. Seventy-five patients were enrolled in the study. Quantitative attenuation-corrected SPECT evaluation showed no inferiority for contrast ratio and SNR issued from FBP CT or ASiR CT (respectively, 13.41 ± 7.83 vs. 13.45 ± 7.99 and 2.33 ± 0.83 vs. 2.32 ± 0.84). Qualitative image analysis showed no difference between attenuation-corrected SPECT images issued from FBP CT or ASiR CT for both interpreters (respectively, 3.5 ± 0.6 vs. 3.5 ± 0.6 and 3.6 ± 0.5 vs. 3.6 ± 0.5). Quantitative CT evaluation showed no inferiority for SNR between FBP and ASiR CT images (respectively, 0.93 ± 0.16 and 1.07 ± 0.17). Qualitative image analysis showed no quality difference between FBP and ASiR CT images for both interpreters (respectively, 3.8 ± 0.5 vs. 3.6 ± 0.5 and 4.0 ± 0.1 vs. 4.0 ± 0.2). Mean CT dose index volume, dose-length product, and effective dose for ASiR CT (3.0 ± 2.0 mGy, 148 ± 85 mGy⋅cm, and 2.2 ± 1.3 mSv) were significantly lower than for FBP CT (8.5 ± 3.7 mGy, 365 ± 160 mGy⋅cm, and 5.5 ± 2.4 mSv). The use of 70% ASiR blending in bone SPECT/CT can reduce the CT radiation dose by 60%, with no sacrifice in attenuation-corrected SPECT and CT image quality, compared with the conventional protocol using FBP CT

  9. Preliminary results of radiation dose escalation for locally advanced nasopharyngeal carcinoma

    SciTech Connect

    Kwong, Dora L.W. . E-mail: dlwkwong@hkucc.hku.hk; Sham, Jonathan S.T.; Leung, Lucullus H.T.; Cheng, Ashley C.K.; Ng, W.M.; Kwong, Philip W.K.; Lui, W.M.; Yau, C.C.; Wu, P.M.; Wei, William; Au, Gordon

    2006-02-01

    Purpose: To study the safety and efficacy of dose escalation in tumor for locally advanced nasopharyngeal carcinoma (NPC). Methods and Materials: From September 2000 to June 2004, 50 patients with T3-T4 NPC were treated with intensity-modulated radiotherapy (IMRT). Fourteen patients had Stage III and 36 patients had Stage IVA-IVB disease. The prescribed dose was 76 Gy to gross tumor volume (GTV), 70 Gy to planning target volume (PTV), and 72 Gy to enlarged neck nodes (GTVn). All doses were given in 35 fractions over 7 weeks. Thirty-four patients also had concurrent cisplatin and induction or adjuvant PF (cisplatin and 5-fluorouracil). Results: The average mean dose achieved in GTV, GTVn, and PTV were 79.5 Gy, 75.3 Gy, and 74.6 Gy, respectively. The median follow-up was 25 months, with 4 recurrences: 2 locoregional and 2 distant failures. All patients with recurrence had IMRT alone without chemotherapy. The 2-year locoregional control rate, distant metastases-free and disease-free survivals were 95.7%, 94.2%, and 93.1%, respectively. One treatment-related death caused by adjuvant chemotherapy occurred. The 2-year overall survival was 92.1%. Conclusions: Dose escalation to 76 Gy in tumor is feasible with T3-T4 NPC and can be combined with chemotherapy. Initial results showed good local control and survival.

  10. The antidepressant effect of sertraline is not enhanced by dose titration: results from an outpatient clinical trial.

    PubMed

    Schweizer, E; Rynn, M; Mandos, L A; Demartinis, N; García-España, F; Rickels, K

    2001-05-01

    A previous report suggested that 5 weeks of continued treatment with 20 mg of fluoxetine was approximately as effective as double-blind titration to a dose of 60 mg in patients who had failed to respond to 3 weeks of initial treatment at 20 mg. The current study was undertaken to evaluate whether 150 mg of sertraline was any more effective than 50 mg in treating depressed patients who were non-responders at 3 weeks. Ninety-one outpatients with DSM-IV major depressive disorder who had a 17-item Hamilton Depression Rating Scale (HAM-D) score > or = 18 were treated with open label sertraline for 3 weeks. Patients who did not achieve remission (defined as 17-item HAM-D total score < or = 8 by week 3) were then randomized to 5 more weeks of double-blind treatment with either 50 mg of sertraline or immediate titration to 150 mg of sertraline. Efficacy was assessed at each visit with the HAM-D, Clinical Global Impressions (CGI)-severity and improvement scale, and the Hopkins Symptom Checklist. There were no significant between-group differences in clinical or demographic features at baseline for the three treatment groups. After 3 weeks of open-label treatment, 16 patients were not randomized, of whom 11 (69%) met responder criteria. The remaining patients were randomized, double-blind, to 50 mg of sertraline (n = 37; HAM-D = 19.2 +/- 5.0) or 150 mg of sertraline (n = 38; HAM-D = 18.4 +/- 5.0). PROC-Mixed analyses found no significant difference in slopes for any outcome measure when comparing 50 mg and 150 mg sertraline treatment groups. At week 8 (LOCF), the overall remission rate (HAM-D < or = 8) for 3-week non-responders was 40%, with no statistically significant between-group difference for the 50 mg versus 150 mg doses of sertraline (P > 0.10). A completer analysis yielded similar results. Adverse events were mostly mild on both doses of sertraline and led to few treatment discontinuations. The results suggest that for most patients continued treatment with 50 mg

  11. Use of the Jackknife Statistic To Establish the External Validity of Discriminant Analysis Results.

    ERIC Educational Resources Information Center

    Daniel, Larry G.

    That the jackknifing technique is superior to traditional techniques for assessing the external validity of statistical results of discriminant analysis is defended. Traditional approaches assessed include: (1) the empirical method, in which the discriminant function coefficients (DFCs) obtained in a given analysis are applied to predict group…

  12. Statistical evaluation of characteristic SDDLV-induced stress resultants to discriminate between undamaged and damaged elements

    NASA Astrophysics Data System (ADS)

    Hansen, L. M.; Johansen, R. J.; Ulriksen, M. D.; Tcherniak, D.; Damkilde, L.

    2015-07-01

    The stochastic dynamic damage location vector (SDDLV) method utilizes the vectors from the kernel of a damaged-induced transfer function matrix change to localize damages in a structure. The kernel vectors associated with the lowest singular values are converted into static pseudo-loads and applied alternately to an undamaged reference model with known stiffness matrix, hereby, theoretically, yielding characteristic stress resultants approaching zero in the damaged elements. At present, the discrimination between potentially damaged elements and undamaged ones is typically conducted on the basis of modified characteristic stress resultants, which are compared to a pre-defined tolerance value, without any thorough statistical evaluation. In the present paper, it is tested whether three widely-used statistical pattern-recognition-based damage-detection methods can provide an effective statistical evaluation of the characteristic stress resultants, hence facilitating general discrimination between damaged and undamaged elements. The three detection methods in question enable outlier analysis on the basis of, respectively, Euclidian distance, Hotelling's T2 statistics, and Mahalanobis distance. The study of the applicability of these methods is based on experimentally obtained accelerations of a cantilevered residential-sized wind turbine blade subjected to an unmeasured multi-impulse load. The characteristic stress resultants are derived by applying the static pseudo-loads to a representative finite element (FE) model of the actual blade.

  13. Measuring Classroom Management Expertise (CME) of Teachers: A Video-Based Assessment Approach and Statistical Results

    ERIC Educational Resources Information Center

    König, Johannes

    2015-01-01

    The study aims at developing and exploring a novel video-based assessment that captures classroom management expertise (CME) of teachers and for which statistical results are provided. CME measurement is conceptualized by using four video clips that refer to typical classroom management situations in which teachers are heavily challenged…

  14. Using the Descriptive Bootstrap to Evaluate Result Replicability (Because Statistical Significance Doesn't)

    ERIC Educational Resources Information Center

    Spinella, Sarah

    2011-01-01

    As result replicability is essential to science and difficult to achieve through external replicability, the present paper notes the insufficiency of null hypothesis statistical significance testing (NHSST) and explains the bootstrap as a plausible alternative, with a heuristic example to illustrate the bootstrap method. The bootstrap relies on…

  15. Reporting of statistically significant results at ClinicalTrials.gov for completed superiority randomized controlled trials.

    PubMed

    Dechartres, Agnes; Bond, Elizabeth G; Scheer, Jordan; Riveros, Carolina; Atal, Ignacio; Ravaud, Philippe

    2016-11-30

    Publication bias and other reporting bias have been well documented for journal articles, but no study has evaluated the nature of results posted at ClinicalTrials.gov. We aimed to assess how many randomized controlled trials (RCTs) with results posted at ClinicalTrials.gov report statistically significant results and whether the proportion of trials with significant results differs when no treatment effect estimate or p-value is posted. We searched ClinicalTrials.gov in June 2015 for all studies with results posted. We included completed RCTs with a superiority hypothesis and considered results for the first primary outcome with results posted. For each trial, we assessed whether a treatment effect estimate and/or p-value was reported at ClinicalTrials.gov and if yes, whether results were statistically significant. If no treatment effect estimate or p-value was reported, we calculated the treatment effect and corresponding p-value using results per arm posted at ClinicalTrials.gov when sufficient data were reported. From the 17,536 studies with results posted at ClinicalTrials.gov, we identified 2823 completed phase 3 or 4 randomized trials with a superiority hypothesis. Of these, 1400 (50%) reported a treatment effect estimate and/or p-value. Results were statistically significant for 844 trials (60%), with a median p-value of 0.01 (Q1-Q3: 0.001-0.26). For the 1423 trials with no treatment effect estimate or p-value posted, we could calculate the treatment effect and corresponding p-value using results reported per arm for 929 (65%). For 494 trials (35%), p-values could not be calculated mainly because of insufficient reporting, censored data, or repeated measurements over time. For the 929 trials we could calculate p-values, we found statistically significant results for 342 (37%), with a median p-value of 0.19 (Q1-Q3: 0.005-0.59). Half of the trials with results posted at ClinicalTrials.gov reported a treatment effect estimate and/or p-value, with significant

  16. Dosing of chemotherapy in obese and cachectic patients: results of a national survey.

    PubMed

    Anglada-Martínez, Helena; Riu-Viladoms, Gisela; do Pazo-Oubiña, Fernando; Molas-Ferrer, Gloria; Mangues-Bafalluy, Irene; Codina-Jané, Carles; Creus-Baró, Natàlia

    2014-06-01

    It is not unusual to find obese and cachectic patients in the hematology oncology setting. However, information on dosage in these groups is scarce. The objectives of our study were to explore the dosing strategies applied in the treatment of obese and cachectic cancer patients and to determine whether these strategies are applied in clinical trials. Members of the Spanish Group for the Development of Hematology-Oncology Pharmacy (GEDEFO). We invited all cancer hospital pharmacists to participate in a survey. Descriptive statistics of the dosing strategies approaches. We invited 159 eligible hospitals to participate, and 38 responded to the survey. A total of 50 surveys were received: different strategies were applied by different physicians from the same hospital and by hematology and oncology departments. Body mass index was used to define obesity and cachexia in 40 and 30 % of the cases, respectively. Capping the body surface area (BSA) was the approach most commonly followed (64.1 %) in obese patients, whereas no specific approach was adopted in cachectic patients. In hematology patients, the BSA calculation was based on ideal body weight or adjusted body weight in 16.0 % of cases (n = 2) and 50.0 % of cases (n = 6), respectively; in oncology patients, use of adjusted or ideal body weight was negligible. Actual body weight was the main approach in obese patients (35 surveys) and cachectic patients (48 surveys). Creatinine clearance was assessed mainly using the Cockcroft and Gault equation (around 76.0 % of responses). As for clinical trials, 64.1 % of the respondents (n = 25 hospitals) considered the criteria from each clinical trial individually. Dose adjustments are more frequent in obese patients than in cachectic patients. In cancer oncology patients, dose is adjusted mainly by hematology and hematopoietic cell transplant teams. Capping BSA is the most frequent strategy, followed by calculating actual body weight.

  17. Preliminary Results of Indoor Radon/thoron Concentrations and Terrestrial Gamma Doses in Gejiu, Yunnan, China

    SciTech Connect

    Ishikawa, Tetsuo; Tokonami, Shinji; Kobayashi, Yosuke; Yoshinaga, Shinji; Sun Quafu; Min Xiangdong

    2008-08-07

    A preliminary survey on indoor radon/thoron and external gamma ray dose rate was conducted for houses in Gejiu city and its neighboring village in Yunnan Province, China. As a result of the radon/thoron measurements for about 50 houses, very high thoron concentrations were found in some hoses (maximum: 7,900 Bq/m{sup 3}). The mean annual dose from thoron decay products was estimated to be larger than that from radon decay products (2.9 mSv vs. 1.6 mSv). Further dosimetric and epidemiological studies are needed to investigate the possible effects of radon and thoron.

  18. 42 CFR 82.4 - How Will DOL Use the Results of the NIOSH Dose Reconstructions?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES METHODS FOR CONDUCTING DOSE RECONSTRUCTION UNDER... reconstruction results together with information on cancer diagnosis and other personal information provided to... probability that the cancer of the covered employee was caused by radiation exposure at a covered facility...

  19. Planck 2015 results: XVI. Isotropy and statistics of the CMB

    SciTech Connect

    Ade, P. A. R.; Aghanim, N.; Akrami, Y.; Aluri, P. K.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Basak, S.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J. -P.; Bersanelli, M.; Bielewicz, P.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J. -F.; Casaponsa, B.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Contreras, D.; Couchot, F.; Coulais, A.; Crill, B. P.; Cruz, M.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F. -X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Fantaye, Y.; Fergusson, J.; Fernandez-Cobos, R.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Frolov, A.; Galeotta, S.; Galli, S.; Ganga, K.; Gauthier, C.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huang, Z.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kim, J.; Kisner, T. S.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J. -M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; Liu, H.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Marinucci, D.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mikkelsen, K.; Mitra, S.; Miville-Deschênes, M. -A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Pant, N.; Paoletti, D.; Pasian, F.; Patanchon, G.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Popa, L.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J. -L.; Rachen, J. P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Rotti, A.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Souradeep, T.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A. -S.; Sygnet, J. -F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Trombetti, T.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Yvon, D.; Zacchei, A.; Zibin, J. P.; Zonca, A.

    2016-09-20

    In this paper, we test the statistical isotropy and Gaussianity of the cosmic microwave background (CMB) anisotropies using observations made by the Planck satellite. Our results are based mainly on the full Planck mission for temperature, but also include some polarization measurements. In particular, we consider the CMB anisotropy maps derived from the multi-frequency Planck data by several component-separation methods. For the temperature anisotropies, we find excellent agreement between results based on these sky maps over both a very large fraction of the sky and a broad range of angular scales, establishing that potential foreground residuals do not affect our studies. Tests of skewness, kurtosis, multi-normality, N-point functions, and Minkowski functionals indicate consistency with Gaussianity, while a power deficit at large angular scales is manifested in several ways, for example low map variance. The results of a peak statistics analysis are consistent with the expectations of a Gaussian random field. The “Cold Spot” is detected with several methods, including map kurtosis, peak statistics, and mean temperature profile. We thoroughly probe the large-scale dipolar power asymmetry, detecting it with several independent tests, and address the subject of a posteriori correction. Tests of directionality suggest the presence of angular clustering from large to small scales, but at a significance that is dependent on the details of the approach. We perform the first examination of polarization data, finding the morphology of stacked peaks to be consistent with the expectations of statistically isotropic simulations. Finally, where they overlap, these results are consistent with the Planck 2013 analysis based on the nominal mission data and provide our most thorough view of the statistics of the CMB fluctuations to date.

  20. Radiation doses resulting from variations in spent fuel/waste management systems without Monitored Retrievable Storage

    SciTech Connect

    Schneider, K.J.; Pelto, P.J.; Lavender, J.C.; Daling, P.M.; Fecht, B.A.

    1987-02-01

    This paper presents results of analyses of radiological dose impacts on the public and the workers of nine potential transportation-related changes in the operation of a hypothetical high-level waste management system that does not include a Monitored Retrievable Storage (MRS) facility. The analyses were performed for the US Department of Energy (DOE) to determine if some of the benefits proposed for the improved performance waste management system (one with an MRS facility) could also benefit the authorized system (one without an MRS facility). The study showed that most of the alternatives evaluated would reduce the radiation doses to the public and the workers. Of the alternatives evaluated, the primary means for reducing these radiation doses is to increase the capacity of the transportation casks.

  1. High-Dose-Rate Prostate Brachytherapy Consistently Results in High Quality Dosimetry

    SciTech Connect

    White, Evan C.; Kamrava, Mitchell R.; Demarco, John; Park, Sang-June; Wang, Pin-Chieh; Kayode, Oluwatosin; Steinberg, Michael L.; Demanes, D. Jeffrey

    2013-02-01

    Purpose: We performed a dosimetry analysis to determine how well the goals for clinical target volume coverage, dose homogeneity, and normal tissue dose constraints were achieved with high-dose-rate (HDR) prostate brachytherapy. Methods and Materials: Cumulative dose-volume histograms for 208 consecutively treated HDR prostate brachytherapy implants were analyzed. Planning was based on ultrasound-guided catheter insertion and postoperative CT imaging; the contoured clinical target volume (CTV) was the prostate, a small margin, and the proximal seminal vesicles. Dosimetric parameters analyzed for the CTV were D90, V90, V100, V150, and V200. Dose to the urethra, bladder, bladder balloon, and rectum were evaluated by the dose to 0.1 cm{sup 3}, 1 cm{sup 3}, and 2 cm{sup 3} of each organ, expressed as a percentage of the prescribed dose. Analysis was stratified according to prostate size. Results: The mean prostate ultrasound volume was 38.7 {+-} 13.4 cm{sup 3} (range: 11.7-108.6 cm{sup 3}). The mean CTV was 75.1 {+-} 20.6 cm{sup 3} (range: 33.4-156.5 cm{sup 3}). The mean D90 was 109.2% {+-} 2.6% (range: 102.3%-118.4%). Ninety-three percent of observed D90 values were between 105 and 115%. The mean V90, V100, V150, and V200 were 99.9% {+-} 0.05%, 99.5% {+-} 0.8%, 25.4% {+-} 4.2%, and 7.8% {+-} 1.4%. The mean dose to 0.1 cm{sup 3}, 1 cm{sup 3}, and 2 cm{sup 3} for organs at risk were: Urethra: 107.3% {+-} 3.0%, 101.1% {+-} 14.6%, and 47.9% {+-} 34.8%; bladder wall: 79.5% {+-} 5.1%, 69.8% {+-} 4.9%, and 64.3% {+-} 5.0%; bladder balloon: 70.3% {+-} 6.8%, 59.1% {+-} 6.6%, and 52.3% {+-} 6.2%; rectum: 76.3% {+-} 2.5%, 70.2% {+-} 3.3%, and 66.3% {+-} 3.8%. There was no significant difference between D90 and V100 when stratified by prostate size. Conclusions: HDR brachytherapy allows the physician to consistently achieve complete prostate target coverage and maintain normal tissue dose constraints for organs at risk over a wide range of target volumes.

  2. A statistical comparison of impact and ambient testing results from the Alamosa Canyon Bridge

    SciTech Connect

    Doebling, S.W.; Farrar, C.R.; Cornwell, P.

    1996-12-31

    In this paper, the modal properties of the Alamosa Canyon Bridge obtained using ambient data are compared to those obtained from impact hammer vibration tests. Using ambient sources of excitation to determine the modal characteristics of large civil engineering structures is desirable for several reasons. The forced vibration testing of such structures generally requires a large amount of specialized equipment and trained personnel making the tests quite expensive. Also, an automated health monitoring system for a large civil structure will most likely use ambient excitation. A modal identification procedure based on a statistical Monte Carlo analysis using the Eigensystem Realization Algorithm is used to compute the modal parameters and their statistics. The results show that for most of the measured modes, the differences between the modal frequencies of the ambient and hammer data sets are statistically significant. However, the differences between the corresponding damping ratio results are not statistically significant. Also, one of the modes identified from the hammer test data was not identifiable from the ambient data set.

  3. Variation in CT pediatric head examination radiation dose: results from a national survey.

    PubMed

    Kanal, Kalpana M; Graves, Janessa M; Vavilala, Monica S; Applegate, Kimberly E; Jarvik, Jeffrey G; Rivara, Frederick P

    2015-03-01

    OBJECTIVE. The purpose of this article is to examine the variation in radiation dose, CT dose index volume (CTDIvol), and dose-length product (DLP) for pediatric head CT examinations as a function of hospital characteristics across the United States. MATERIALS AND METHODS. A survey inquiring about hospital information, CT scanners, pediatric head examination protocol, CTDIvol, and DLP was mailed to a representative sample of U.S. hospitals. Follow-up mailings were sent to nonrespondents. Descriptive characteristics of respondents and nonrespondents were compared using design-based Pearson chi-square tests. Dose estimates were compared across hospital characteristics using Bonferroni-adjusted Wald test. Hospital-level factors associated with dose estimates were evaluated using multiple linear regressions and modified Poisson regression models. RESULTS. Surveys were sent out to 751 hospitals; 292 responded to the survey, of which 253 were eligible (35.5% response rate, calculated as number of hospitals who completed surveys [n = 253] divided by sum of number who were eligible and initially consented [n = 712] plus estimated number who were eligible among those who refused [n = 1]). Most respondents reported using MDCT scanners (99.2%) and having a dedicated pediatric head CT protocol (93%). Estimated mean reported CTDIvol values were 27.3 mGy (95% CI, 24.4-30.1 mGy), and DLP values were 390.9 mGy × cm (95% CI, 346.6-435.1 mGy × cm). These values did not vary significantly by region, trauma level, teaching status, CT accreditation, number of CT scanners, or report of a dedicated pediatric CT protocol. However, estimated CTDIvol reported by children's hospitals was 19% lower than that reported by general hospitals (p < 0.01). CONCLUSION. Most hospitals (82%) report doses that meet American College of Radiology accreditation levels. However, [corrected] the mean CTDI(vol) at children's hospitals was approximately 7 mGy (21%, adjusted for covariates), lower than that

  4. New Statistical Results on the Angular Distribution of Gamma-Ray Bursts

    SciTech Connect

    Balazs, Lajos G.; Horvath, Istvan; Vavrek, Roland

    2008-05-22

    We presented the results of several statistical tests of the randomness in the angular sky-distribution of gamma-ray bursts in BATSE Catalog. Thirteen different tests were presented based on Voronoi tesselation, Minimal spanning tree and Multifractal spectrum for five classes (short1, short2, intermediate, long1, long2) of gamma-ray bursts, separately. The long1 and long2 classes are distributed randomly. The intermediate subclass, in accordance with the earlier results of the authors, is distributed non-randomly. Concerning the short subclass earlier statistical tests also suggested some departure from the random distribution, but not on a high enough confidence level. The new tests presented in this article suggest also non-randomness here.

  5. Electron Attachment to SF(6) Under Well Defined Conditions: Comparison of Statistical Modeling Results to Experiments

    DTIC Science & Technology

    2007-08-01

    Avogadro constant , EA is the electron affinity (at 0 K, by definition), AS" is the entropy change due to electron attachment at temperature T, and...measure rate constants for electron attachment to SF6 and thermal detachment from SF6’. In a recent series of papers, these results were combined...hexafluoride Statistical theory Rate constants 16. SECURITY CLASSIFICATION OF: a. REPORT UNCL b. ABSTRACT UNCL c. THIS PAGE UNCL 17. LIMITATION OF

  6. Variability analysis of AGN: a review of results using new statistical criteria

    NASA Astrophysics Data System (ADS)

    Zibecchi, L.; Andruchow, I.; Cellone, S. A.; Romero, G. E.; Combi, J. A.

    We present here a re-analysis of the variability results of a sample of active galactic nuclei (AGN), which have been observed on several sessions with the 2.15 m "Jorge Sahade" telescope (CASLEO), San Juan, Argentina, and whose results are published (Romero et al. 1999, 2000, 2002; Cellone et al. 2000). The motivation for this new analysis is the implementation, dur- ing the last years, of improvements in the statistical criteria applied, taking quantitatively into account the incidence of the photometric errors (Cellone et al. 2007). This work is framed as a first step in an integral study on the statistical estimators of AGN variability. This study is motivated by the great diversity of statistical tests that have been proposed to analyze the variability of these objects. Since we note that, in some cases, the results of the object variability depend on the test used, we attempt to make a com- parative study of the various tests and analyze, under the given conditions, which of them is the most efficient and reliable.

  7. Results of comparative assessment of US and Foreign Nuclear Power Plant dose experience and dose reduction programs

    SciTech Connect

    Baum, J.W.; Horan, J.R.; Dionne, B.J.

    1984-01-01

    Based on data evaluated to date it is clear that US plants have higher collective dose equivalents per reactor and per MW-y generated than most other countries. Factors which contribute to low doses include: (1) minimization of cobalt in primary system components exposed to water, (2) careful control of primary system oxygen and pH, (3) good primary system water purity to minimize corrosion product formation, (4) careful plant design, layout and component segration and shielding, (5) management interest and commitment, (6) minimum number of workers and in-depth worker training, (7) use of special tools, and (8) plant standardization. It should be pointed out that reductions in exposure are more difficult and costly in plants already built and operating. The cost-effectiveness of dose reduction efforts at US plants should be carefully evaluated before recommendations are made concerning existing plants.

  8. GPA: a statistical approach to prioritizing GWAS results by integrating pleiotropy and annotation.

    PubMed

    Chung, Dongjun; Yang, Can; Li, Cong; Gelernter, Joel; Zhao, Hongyu

    2014-11-01

    Results from Genome-Wide Association Studies (GWAS) have shown that complex diseases are often affected by many genetic variants with small or moderate effects. Identifications of these risk variants remain a very challenging problem. There is a need to develop more powerful statistical methods to leverage available information to improve upon traditional approaches that focus on a single GWAS dataset without incorporating additional data. In this paper, we propose a novel statistical approach, GPA (Genetic analysis incorporating Pleiotropy and Annotation), to increase statistical power to identify risk variants through joint analysis of multiple GWAS data sets and annotation information because: (1) accumulating evidence suggests that different complex diseases share common risk bases, i.e., pleiotropy; and (2) functionally annotated variants have been consistently demonstrated to be enriched among GWAS hits. GPA can integrate multiple GWAS datasets and functional annotations to seek association signals, and it can also perform hypothesis testing to test the presence of pleiotropy and enrichment of functional annotation. Statistical inference of the model parameters and SNP ranking is achieved through an EM algorithm that can handle genome-wide markers efficiently. When we applied GPA to jointly analyze five psychiatric disorders with annotation information, not only did GPA identify many weak signals missed by the traditional single phenotype analysis, but it also revealed relationships in the genetic architecture of these disorders. Using our hypothesis testing framework, statistically significant pleiotropic effects were detected among these psychiatric disorders, and the markers annotated in the central nervous system genes and eQTLs from the Genotype-Tissue Expression (GTEx) database were significantly enriched. We also applied GPA to a bladder cancer GWAS data set with the ENCODE DNase-seq data from 125 cell lines. GPA was able to detect cell lines that are

  9. GPA: A Statistical Approach to Prioritizing GWAS Results by Integrating Pleiotropy and Annotation

    PubMed Central

    Li, Cong; Gelernter, Joel; Zhao, Hongyu

    2014-01-01

    Results from Genome-Wide Association Studies (GWAS) have shown that complex diseases are often affected by many genetic variants with small or moderate effects. Identifications of these risk variants remain a very challenging problem. There is a need to develop more powerful statistical methods to leverage available information to improve upon traditional approaches that focus on a single GWAS dataset without incorporating additional data. In this paper, we propose a novel statistical approach, GPA (Genetic analysis incorporating Pleiotropy and Annotation), to increase statistical power to identify risk variants through joint analysis of multiple GWAS data sets and annotation information because: (1) accumulating evidence suggests that different complex diseases share common risk bases, i.e., pleiotropy; and (2) functionally annotated variants have been consistently demonstrated to be enriched among GWAS hits. GPA can integrate multiple GWAS datasets and functional annotations to seek association signals, and it can also perform hypothesis testing to test the presence of pleiotropy and enrichment of functional annotation. Statistical inference of the model parameters and SNP ranking is achieved through an EM algorithm that can handle genome-wide markers efficiently. When we applied GPA to jointly analyze five psychiatric disorders with annotation information, not only did GPA identify many weak signals missed by the traditional single phenotype analysis, but it also revealed relationships in the genetic architecture of these disorders. Using our hypothesis testing framework, statistically significant pleiotropic effects were detected among these psychiatric disorders, and the markers annotated in the central nervous system genes and eQTLs from the Genotype-Tissue Expression (GTEx) database were significantly enriched. We also applied GPA to a bladder cancer GWAS data set with the ENCODE DNase-seq data from 125 cell lines. GPA was able to detect cell lines that are

  10. Probabilistic dose-response modeling: case study using dichloromethane PBPK model results.

    PubMed

    Marino, Dale J; Starr, Thomas B

    2007-12-01

    A revised assessment of dichloromethane (DCM) has recently been reported that examines the influence of human genetic polymorphisms on cancer risks using deterministic PBPK and dose-response modeling in the mouse combined with probabilistic PBPK modeling in humans. This assessment utilized Bayesian techniques to optimize kinetic variables in mice and humans with mean values from posterior distributions used in the deterministic modeling in the mouse. To supplement this research, a case study was undertaken to examine the potential impact of probabilistic rather than deterministic PBPK and dose-response modeling in mice on subsequent unit risk factor (URF) determinations. Four separate PBPK cases were examined based on the exposure regimen of the NTP DCM bioassay. These were (a) Same Mouse (single draw of all PBPK inputs for both treatment groups); (b) Correlated BW-Same Inputs (single draw of all PBPK inputs for both treatment groups except for bodyweights (BWs), which were entered as correlated variables); (c) Correlated BW-Different Inputs (separate draws of all PBPK inputs for both treatment groups except that BWs were entered as correlated variables); and (d) Different Mouse (separate draws of all PBPK inputs for both treatment groups). Monte Carlo PBPK inputs reflect posterior distributions from Bayesian calibration in the mouse that had been previously reported. A minimum of 12,500 PBPK iterations were undertaken, in which dose metrics, i.e., mg DCM metabolized by the GST pathway/L tissue/day for lung and liver were determined. For dose-response modeling, these metrics were combined with NTP tumor incidence data that were randomly selected from binomial distributions. Resultant potency factors (0.1/ED(10)) were coupled with probabilistic PBPK modeling in humans that incorporated genetic polymorphisms to derive URFs. Results show that there was relatively little difference, i.e., <10% in central tendency and upper percentile URFs, regardless of the case

  11. Long-term results of breast cancer irradiation treatment with low-dose-rate external irradiation

    SciTech Connect

    Pierquin, Bernard; Tubiana, Maurice . E-mail: maurice.tubiana@biomedicale.univ-paris5.fr; Pan, Camille; Lagrange, Jean-Leon; Calitchi, Elie; Otmezguine, Yves

    2007-01-01

    Purpose: The aim of this study was to assess beam therapy with low-dose-rate (LDR) external irradiation in a group of patients with breast cancer. Methods and Materials: This trial compared, from 1986 to 1989, patients with advanced breast cancer treated either by conventional fractionation or low-dose-rate (LDR) external radiotherapy (dose-rate 15 mGy/min, 5 sessions of 9 Gy delivered on 5 consecutive days). Results: A total of 21 patients were included in the fractionated therapy arm. At follow-up 15 years after treatment, 7 local recurrences had occurred, 3 patients had died of cancer, 18 patients were alive, 10 were without evidence of disease, and 6 had evidence of disease. A total of 22 patients had been included in the LDR arm of the study. Of these, 11 had received a dose of 45 Gy; thereafter, in view of severe local reactions, the dose was reduced to 35 Gy. There was no local recurrence in patients who had received 45 Gy, although there were 2 local recurrences among the 11 patients after 35 Gy. The sequelae were severe in patients who received 45 Gy but were comparable to those observed in patients treated by fractionated radiotherapy who received 35 Gy. The higher efficacy of tumor control in patients treated by LDR irradiation as well as the lower tolerance of normal tissue are probably related to the lack of repopulation. Conclusion: Although the patient numbers in this study are limited, based on our study results we conclude that the data for LDR irradiation are encouraging and that further investigation is warranted.

  12. Results of Dose Control and Measurement Plans Appliedfor SPEAR3 Commissioning Year (FY04)

    SciTech Connect

    Khater, Hesham; Liu, James; Prinz, Alyssa; Allan, Jim; Rokni, Sayed; /SLAC

    2007-02-12

    Dose control and measurement plans for the SPEAR3 Booster and storage ring have taken place during the SPEAR3 commissioning. The initial commissioning period (SPEAR3 start-up) covered the time period from the beginning of November 2003 to the early part of March 2004. The period from the beginning of March to the beginning of August 2004 has been mostly dedicated to the scientific program. The initial commissioning period was characterized with frequent injection and significantly higher losses. In comparison, the scientific program period was characterized with more stable beam operation with limited number of injections per day and lower beam losses. Three types of dose measurements, passive, active and special measurements, were implemented around the SPEAR3 Booster and storage ring. Based on the expected radiation hazards, several dose control measures were adopted at several stages of the commissioning. In the early stages of commissioning, areas within 4.5 m from the walls of the Booster and storage ring were designated as Radiation Areas (RA). Areas outside RA were classified as Radiologically Controlled Area (RCA). Access to these areas required less training than the radiation areas. A monthly review of the accelerator operation conditions and radiation measurement results were used to determine the changes needed for the RA classification status and associated dose control measures.

  13. Higher Chest Wall Dose Results in Improved Locoregional Outcome in Patients Receiving Postmastectomy Radiation

    SciTech Connect

    Panoff, Joseph E.; Takita, Cristiane; Hurley, Judith; Reis, Isildinha M.; Zhao, Wei; Rodgers, Steven E.; Gunaseelan, Vijayalakshmi; Wright, Jean L.

    2012-03-01

    Purpose: Randomized trials demonstrating decreased locoregional recurrence (LRR) and improved overall survival (OS) in women receiving postmastectomy radiation therapy (PMRT) used up to 50 Gy to the chest wall (CW), but in practice, many centers boost the CW dose to {>=}60 Gy, despite lack of data supporting this approach. We evaluated the relationship between CW dose and clinical outcome. Methods and Materials: We retrospectively reviewed medical records of 582 consecutively treated patients who received PMRT between January 1999 and December 2009. We collected data on patient, disease, treatment characteristics, and outcomes of LRR, progression-free survival (PFS) and OS. Results: Median follow-up from the date of diagnosis was 44.7 months. The cumulative 5-year incidence of LRR as first site of failure was 6.2%. CW dose for 7% (43 patients) was {<=}50.4 Gy (range, 41.4-50.4 Gy) and 93% received >50.4 Gy (range, 52.4-74.4 Gy). A CW dose of >50.4 Gy vs. {<=}50.4 Gy was associated with lower incidence of LRR, a 60-month rate of 5.7% (95% confidence interval [CI], 3.7-8.2) vs. 12.7% (95% CI, 4.5-25.3; p = 0.054). Multivariate hazard ratio (HR) for LRR controlling for race, receptor status, and stage was 2.62 (95% CI, 1.02-7.13; p = 0.042). All LRR in the low-dose group occurred in patients receiving 50 to 50.4 Gy. Lower CW dose was associated with worse PFS (multivariate HR, 2.73; 95% CI, 1.64-4.56; p < 0.001) and OS (multivariate HR, 3.88; 95% CI, 2.16-6.99; p < 0.001). Conclusions: The addition of a CW boost above 50.4 Gy resulted in improved locoregional control and survival in this cohort patients treated with PMRT for stage II-III breast cancer. The addition of a CW boost to standard-dose PMRT is likely to benefit selected high-risk patients. The optimal technique, target volume, and patient selection criteria are unknown. The use of a CW boost should be studied prospectively, as has been done in the setting of breast conservation.

  14. Quarter regular dose non-enhanced CT for urinary stone: added value of adaptive statistical iterative reconstruction.

    PubMed

    Kim, Seung Ho; Baek, Soo Heui; Yoon, Jung-Hee; Lim, Yun-Jung; Baek, Hye Jin; Kim, Seon-Jeong; Eun, Choong Ki

    2014-11-01

    As urinary stone diseases are common in young adults and have a high recurrence rate, repetitive computed tomography (CT) scans would increase the radiation hazard. Therefore, CT radiation dose reduction is needed in the diagnosis of urinary stones. To prospectively evaluate the added value of adaptive statistical iterative reconstruction (ASIR) applied to half-dose (HDCT) and quarter regular dose non-enhanced CT (QDCT) for the detection of urinary stones. One hundred and twelve consecutive patients who presented with acute flank pain and had clinically suspected urinary stones were initially eligible. All patients underwent non-enhanced CT that consisted of HDCT (120 kVp, 100 mAs) and QDCT (120 kVp, 40 mAs). The images were reconstructed separately with a 50% ASIR blending ratio. Two radiologists independently performed a 2-week interval reading to detect urinary stones on a per stone basis (size ≥1 mm) from the QDCT images to the ASIR applied images. Two weeks later, the HDCT images were analyzed in the same manner. The CT image noise was measured for each image set. The sensitivity for urinary stone detection for each set was compared using the McNemar test. A total of 114 urinary stones were found in 48 patients (37 men, 11 women; mean age, 46 years; range, 19-71 years). After applying ASIR to the QDCT images, the sensitivity increased from 70% to 80% for reader 1 and from 69% to 82% for reader 2 (P = 0.001, respectively). However, in the HDCT images, the sensitivity was unchanged for both readers (reader 1, 87%; reader 2, 89%). The measured noise significantly decreased from 40.2 to 27.7 after applying ASIR to the QDCT images and from 25.1 to 17.6 after applying ASIR to the HDCT images (P = 0.001 for both). Although ASIR showed no added diagnostic value for HDCT images, it improved the sensitivity for the detection of urinary stones based on QDCT images. © The Foundation Acta Radiologica 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  15. Statistical tools for dose individualization of mycophenolic acid and tacrolimus co-administered during the first month after renal transplantation.

    PubMed

    Musuamba, Flora T; Mourad, Michel; Haufroid, Vincent; De Meyer, Martine; Capron, Arnaud; Delattre, Isabelle K; Verbeeck, Roger K; Wallemacq, Pierre

    2013-05-01

    To predict simultaneously the area under the concentration-time curve during one dosing interval [AUC(0,12 h)] for mycophenolic acid (MPA) and tacrolimus (TAC), when concomitantly used during the first month after transplantation, based on common blood samples. Data were from two different sources, real patient pharmacokinetic (PK) profiles from 65 renal transplant recipients and 9000 PK profiles simulated from previously published models on MPA or TAC in the first month after transplantation. Multiple linear regression (MLR) and Bayesian estimation using optimal samples were performed to predict MPA and TAC AUC(0,12 h) based on two concentrations. The following models were retained: AUC(0,12 h) = 16.5 + 4.9 × C1.5 + 6.7 × C3.5 (r(2) = 0.82, rRMSE = 9%, with simulations and r(2) = 0.66, rRMSE = 24%, with observed data) and AUC(0,12 h) = 24.3 + 5.9 × C1.5 + 12.2 × C3.5 (r(2) = 0.94, rRMSE = 12.3%, with simulations r(2) = 0.74, rRMSE = 15%, with observed data) for MPA and TAC, respectively. In addition, bayesian estimators were developed including parameter values from final models and values of concentrations at 1.5 and 3.5 h after dose. Good agreement was found between predicted and reference AUC(0,12 h) values: r(2) = 0.90, rRMSE = 13% and r(2) = 0.97, rRMSE = 5% with simulations for MPA and TAC, respectively and r(2) = 0.75, rRMSE = 11% and r(2) = 0.83, rRMSE = 7% with observed data for MPA and TAC, respectively. Statistical tools were developed for simultaneous MPA and TAC therapeutic drug monitoring. They can be incorporated in computer programs for patient dose individualization. © 2012 The Authors. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

  16. SU-E-J-204: Radiation Dose to Patients Resulting From Image Guidance Procedures and AAPM TG-180 Update

    SciTech Connect

    Ding, G; Alaei, P

    2014-06-01

    Purpose: Image-guided radiation therapy (IGRT) is the new paradigm for patient positioning and target localization in radiotherapy. Daily imaging procedures add additional dose to the patient's treatment volume and normal tissues and may expose the organs at risk to unaccounted doses. This presentation is to update the progress of AAPM TG-180 which aims to provide strategies to quantify and account the dose from both MV and kV imaging in patient treatment planning. Methods: Our current knowledge on image guidance dose is presented. A summary of doses from image guidance procedures delivered to patients in relationship with therapeutic doses is given. Different techniques in reducing the image guidance dose are summarized. Typical organ doses resulting from different image acquisition procedures used in IGRT are tabulated. Results: Many techniques to reduce the imaging doses are available in clinical applications. There are large variations between dose to bone and dose to soft tissues for x-rays at kilovoltage energy range. Methods for clinical implementation of accounting for the imaging dose from an imaging procedure are available. Beam data from imaging systems can be generated by combining Monte Carlo simulations and experimental measurements for commissioning imaging beams in the treatment planning. Conclusion: The current treatment planning systems are not yet equipped to perform patient specific dose calculations resulting from kV imaging procedures. The imaging dose from current kV image devices has been significantly reduced and is generally much less than that resulting from MV. Because the magnitude of kV imaging dose is significantly low and the variation between patients is modest, it is feasible to estimate dose based on imaging producers or protocols using tabulated values which provides an alternative to accomplish the task of accounting and reporting imaging doses.

  17. [Statistical comparison of independent validation results for near infrared spectroscopy models predicting calorific value of straw].

    PubMed

    Huang, Cai-jin; Liu, Xian; Yang, Zeng-ling; Han, Lu-jia

    2009-05-01

    Two hundred and twenty-two straw samples, consisting of 170 rice straw samples and 50 wheat straw samples, were collected from 24 provinces of China. Near infrared spectroscopy (NIRS)was applied to build quantitative models for calorific value of straw combining the use of principal component regression (PCR), partial least square regression (PLS)and modified partial least square regression (MPLS). Different scatter correction methods and derivative treatments were adopted to help improve the accuracy of NIRS models. A total of 54 NIRS models were obtained and independent validations were conducted using the same validation set of samples. A statistical comparison of independent validation results was then introduced to evaluate whether the models perform significantly. Bias and bias corrected standard error of prediction (SEP(C)), which are the mean and the standard deviation of the prediction residuals respectively, were compared by the proposed statistical procedures. It was concluded that near infrared spectroscopy was able to predict the calorific value of straw samples rapidly and accurately, with resulting SEP(C)s between 134 and 178 J x g(-1); statistical comparison of biases and SEP(C)s was a reasonable and efficient way to compare spectral pre-processing methods, and select NIRS models predicting calorific value of straw.

  18. Statistics of interacting networks with extreme preferred degrees: Simulation results and theoretical approaches

    NASA Astrophysics Data System (ADS)

    Liu, Wenjia; Schmittmann, Beate; Zia, R. K. P.

    2012-02-01

    Network studies have played a central role for understanding many systems in nature - e.g., physical, biological, and social. So far, much of the focus has been the statistics of networks in isolation. Yet, many networks in the world are coupled to each other. Recently, we considered this issue, in the context of two interacting social networks. In particular, We studied networks with two different preferred degrees, modeling, say, introverts vs. extroverts, with a variety of ``rules for engagement.'' As a first step towards an analytically accessible theory, we restrict our attention to an ``extreme scenario'': The introverts prefer zero contacts while the extroverts like to befriend everyone in the society. In this ``maximally frustrated'' system, the degree distributions, as well as the statistics of cross-links (between the two groups), can depend sensitively on how a node (individual) creates/breaks its connections. The simulation results can be reasonably well understood in terms of an approximate theory.

  19. Activation of hip prostheses in high energy radiotherapy and resultant dose to nearby tissue.

    PubMed

    Keehan, Stephanie; Smith, Ryan L; Millar, Jeremy; Esser, Max; Taylor, Michael L; Lonski, Peta; Kron, Tomas; Franich, Rick D

    2017-03-01

    High energy radiotherapy can produce contaminant neutrons through the photonuclear effect. Patients receiving external beam radiation therapy to the pelvis may have high-density hip prostheses. Metallic materials such as those in hip prostheses, often have high cross-sections for neutron interaction. In this study, Thackray (UK) prosthetic hips have been irradiated by 18 MV radiotherapy beams to evaluate the additional dose to patients from the activation products. Hips were irradiated in- and out-of field at various distances from the beam isocenter to assess activation caused in-field by photo-activation, and neutron activation which occurs both in and out-of-field. NaI(Tl) scintillator detectors were used to measure the subsequent gamma-ray emissions and their half-lives. High sensitivity Mg, Cu, P doped LiF thermoluminescence dosimeter chips (TLD-100H) were used to measure the subsequent dose at the surface of a prosthesis over the 12 h following an in-field irradiation of 10,000 MU to a hip prosthesis located at the beam isocenter in a water phantom. (53) Fe, (56) Mn, and (52) V were identified within the hip following irradiation by radiotherapy beams. The dose measured at the surface of a prosthesis following irradiation in a water phantom was 0.20 mGy over 12 h. The dose at the surface of prostheses irradiated to 200 MU was below the limit of detection (0.05 mGy) of the TLD100H. Prosthetic hips are activated by incident photons and neutrons in high energy radiotherapy, however, the dose resulting from activation is very small. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  20. 42 CFR 82.26 - How will NIOSH report dose reconstruction results?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES METHODS FOR CONDUCTING DOSE RECONSTRUCTION UNDER... dose reconstruction, justification for the decision, and if possible, a quantitative estimate of...

  1. 42 CFR 82.26 - How will NIOSH report dose reconstruction results?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES METHODS FOR CONDUCTING DOSE RECONSTRUCTION UNDER... dose reconstruction, justification for the decision, and if possible, a quantitative estimate of...

  2. 42 CFR 82.26 - How will NIOSH report dose reconstruction results?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES METHODS FOR CONDUCTING DOSE RECONSTRUCTION UNDER... dose reconstruction, justification for the decision, and if possible, a quantitative estimate of...

  3. 42 CFR 82.26 - How will NIOSH report dose reconstruction results?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES METHODS FOR CONDUCTING DOSE RECONSTRUCTION UNDER... dose reconstruction, justification for the decision, and if possible, a quantitative estimate of...

  4. Estimating the Error in Statistical HAMR Object Populations Resulting from Simplified Radiation Pressure Modeling

    NASA Astrophysics Data System (ADS)

    Flegel, S.; Vörsmann, P.; Wiedemann, C.; Kebschull, C.; Braun, V.; Möckel, M.; Gelhaus, J.; Krag, H.; Klinkrad, H.

    2012-09-01

    The high-area-to-mass ratio (HAMR) object population in ESA's MASTER-2009 software (Meteoroid and Space Debris Terrestrial Environment Reference) is dominated by Multi-Layer Insulation debris at large sizes. The underlying model employs two independent mechanisms whereby Multi-Layer Insulation debris is created. These mechanisms are fragmentation events on the one hand and a deterioration process leading to the continuous release of larger objects on the other hand. All debris source models used to create the MASTER debris population rely on a semi-analytical propagator to model the major secular and long periodic orbit perturbations. The orbit parameters of HAMR objects are highly susceptive to radiation pressure effects which can result in fast secular and periodic changes for area-to-mass ratios above about 1 square meter per kilogram. The implementation of radiation pressure in this propagator is limited to the effects of solar irradiation on a spherical object and using a cylindrical Earth shadow. The current paper discusses the applicability of such a simplified theory to large statistical HAMR object populations where the main objective is not to predict the exact future location of a single object but rather to give a correct representation of the overall distribution of all HAMR objects. The basis for the current study is given by a numerical propagator which is supported by published observation results. Initially, the effects of object orientation, Earth albedo and thermal radiation on the orbit evolution are discussed. Results from published observations and simulation results give insight into the validity of the implemented model. Fundamental differences between the orbit prediction of this refined numerical propagator and the semi-analytical propagator are looked at with a view towards large statistical populations. To this end, a plausible, statistical, population of HAMR objects is propagated over an extended time period using both propagation

  5. No difference found in time to publication by statistical significance of trial results: a methodological review

    PubMed Central

    Jefferson, L; Cooper, E; Hewitt, C; Torgerson, T; Cook, L; Tharmanathan, P; Cockayne, S; Torgerson, D

    2016-01-01

    Objective Time-lag from study completion to publication is a potential source of publication bias in randomised controlled trials. This study sought to update the evidence base by identifying the effect of the statistical significance of research findings on time to publication of trial results. Design Literature searches were carried out in four general medical journals from June 2013 to June 2014 inclusive (BMJ, JAMA, the Lancet and the New England Journal of Medicine). Setting Methodological review of four general medical journals. Participants Original research articles presenting the primary analyses from phase 2, 3 and 4 parallel-group randomised controlled trials were included. Main outcome measures Time from trial completion to publication. Results The median time from trial completion to publication was 431 days (n = 208, interquartile range 278–618). A multivariable adjusted Cox model found no statistically significant difference in time to publication for trials reporting positive or negative results (hazard ratio: 0.86, 95% CI 0.64 to 1.16, p = 0.32). Conclusion In contrast to previous studies, this review did not demonstrate the presence of time-lag bias in time to publication. This may be a result of these articles being published in four high-impact general medical journals that may be more inclined to publish rapidly, whatever the findings. Further research is needed to explore the presence of time-lag bias in lower quality studies and lower impact journals. PMID:27757242

  6. Results of 1 year of clinical experience with independent dose calculation software for VMAT fields

    PubMed Central

    Colodro, Juan Fernando Mata; Berna, Alfredo Serna; Puchades, Vicente Puchades; Amores, David Ramos; Baños, Miguel Alcaraz

    2014-01-01

    It is widely accepted that a redundant independent dose calculation (RIDC) must be included in any treatment planning verification procedure. Specifically, volumetric modulated arc therapy (VMAT) technique implies a comprehensive quality assurance (QA) program in which RIDC should be included. In this paper, the results obtained in 1 year of clinical experience are presented. Eclipse from Varian is the treatment planning system (TPS), here in use. RIDC were performed with the commercial software; Diamond® (PTW) which is capable of calculating VMAT fields. Once the plan is clinically accepted, it is exported via Digital Imaging and Communications in Medicine (DICOM) to RIDC, together with the body contour, and then a point dose calculation is performed, usually at the isocenter. A total of 459 plans were evaluated. The total average deviation was -0.3 ± 1.8% (one standard deviation (1SD)). For higher clearance the plans were grouped by location in: Prostate, pelvis, abdomen, chest, head and neck, brain, stereotactic radiosurgery, lung stereotactic body radiation therapy, and miscellaneous. The highest absolute deviation was -0.8 ± 1.5% corresponding to the prostate. A linear fit between doses calculated by RIDC and by TPS produced a correlation coefficient of 0.9991 and a slope of 1.0023. These results are very close to those obtained in the validation process. This agreement led us to consider this RIDC software as a valuable tool for QA in VMAT plans. PMID:25525309

  7. Results of 1 year of clinical experience with independent dose calculation software for VMAT fields.

    PubMed

    Colodro, Juan Fernando Mata; Berna, Alfredo Serna; Puchades, Vicente Puchades; Amores, David Ramos; Baños, Miguel Alcaraz

    2014-10-01

    It is widely accepted that a redundant independent dose calculation (RIDC) must be included in any treatment planning verification procedure. Specifically, volumetric modulated arc therapy (VMAT) technique implies a comprehensive quality assurance (QA) program in which RIDC should be included. In this paper, the results obtained in 1 year of clinical experience are presented. Eclipse from Varian is the treatment planning system (TPS), here in use. RIDC were performed with the commercial software; Diamond(®) (PTW) which is capable of calculating VMAT fields. Once the plan is clinically accepted, it is exported via Digital Imaging and Communications in Medicine (DICOM) to RIDC, together with the body contour, and then a point dose calculation is performed, usually at the isocenter. A total of 459 plans were evaluated. The total average deviation was -0.3 ± 1.8% (one standard deviation (1SD)). For higher clearance the plans were grouped by location in: Prostate, pelvis, abdomen, chest, head and neck, brain, stereotactic radiosurgery, lung stereotactic body radiation therapy, and miscellaneous. The highest absolute deviation was -0.8 ± 1.5% corresponding to the prostate. A linear fit between doses calculated by RIDC and by TPS produced a correlation coefficient of 0.9991 and a slope of 1.0023. These results are very close to those obtained in the validation process. This agreement led us to consider this RIDC software as a valuable tool for QA in VMAT plans.

  8. Novel, single-dose, topical treatment of tinea pedis using terbinafine: results of a dose-finding clinical trial.

    PubMed

    de Chauvin, Martine Feuilhade; Viguié-Vallanet, Claude; Kienzler, Jean-Luc; Larnier, Catherine

    2008-01-01

    Tinea pedis is the most common dermatophytosis requiring topical antifungals for at least 1-4 weeks. To determine the effectiveness of a novel topical single dose formulation of terbinafine (film forming solution-FFS) in the treatment of tinea pedis, 344 outpatients from 43 dermatological centres in France and Bulgaria suffering from tinea pedis with possible extension to soles confirmed by mycological examination (direct and culture) were evaluated for efficacy of terbinafine 1%, 5%, 10% FFS in a randomised double blind vehicle controlled parallel group dose finding study. Evaluations were carried out at baseline, 1 and 6 weeks after a single application of FFS. Effective treatment rate based on negative mycology (direct and culture) and minimal signs and symptoms (two or less with only mild recorded) was measured at week 6. Effective treatment rates at week 6 with terbinafine 1%, 5% and 10% FFS were 66%, 70%, 61% compared with 18% with placebo. All three active preparations were shown to be significantly superior to placebo (P < 0.001). Terbinafine 1% and 5% FFS were shown to be non-inferior to terbinafine 10% FFS. Terbinafine 1% FFS is an effective, safe dose for the treatment of tinea pedis. This novel product represents a significant advance with the enhanced compliance and convenience that it offers.

  9. EPA/NMED/LANL 1998 water quality results: Statistical analysis and comparison to regulatory standards

    SciTech Connect

    B. Gallaher; T. Mercier; P. Black; K. Mullen

    2000-02-01

    Four governmental agencies conducted a round of groundwater, surface water, and spring water sampling at the Los Alamos National Laboratory during 1998. Samples were split among the four parties and sent to independent analytical laboratories. Results from three of the agencies were available for this study. Comparisons of analytical results that were paired by location and date were made between the various analytical laboratories. The results for over 50 split samples analyzed for inorganic chemicals, metals, and radionuclides were compared. Statistical analyses included non-parametric (sign test and signed-ranks test) and parametric (paired t-test and linear regression) methods. The data pairs were tested for statistically significant differences, defined by an observed significance level, or p-value, less than 0.05. The main conclusion is that the laboratories' performances are similar across most of the analytes that were measured. In some 95% of the laboratory measurements there was agreement on whether contaminant levels exceeded regulatory limits. The most significant differences in performance were noted for the radioactive suite, particularly for gross alpha particle activity and Sr-90.

  10. Lung cancer screening - Low dose CT for lung cancer screening: recent trial results and next steps.

    PubMed

    O'Dowd, Emma L; Baldwin, David R

    2017-07-27

    Screening for lung cancer using low-dose computed tomography has already been implemented in North America following the results of the National Lung Screening Trial. Outside North America, clinicians and researchers are addressing issues that may have a major impact on the success of screening programmes by reviewing results of existing trials and by designing new research and pilot programmes. This review summarises the work that has been done to try to answer the remaining questions and highlights potential barriers which may affect screening uptake and cost effectiveness.

  11. Dual effects of phytoestrogens result in u-shaped dose-response curves.

    PubMed Central

    Almstrup, Kristian; Fernández, Mariana F; Petersen, Jørgen H; Olea, Nicolas; Skakkebaek, Niels E; Leffers, Henrik

    2002-01-01

    Endocrine disruptors can affect the endocrine system without directly interacting with receptors, for example, by interfering with the synthesis or metabolism of steroid hormones. The aromatase that converts testosterone to 17beta-estradiol is a possible target. In this paper we describe an assay that simultaneously detects aromatase inhibition and estrogenicity. The principle is similar to that of other MCF-7 estrogenicity assays, but with a fixed amount of testosterone added. The endogenous aromatase activity in MCF-7 cells converts some of the testosterone to 17beta-estradiol, which is assayed by quantifying differences in the expression level of the estrogen-induced pS2 mRNA. Potential aromatase inhibitors can be identified by a dose-dependent reduction in the pS2 mRNA expression level after exposure to testosterone and the test compound. Using this assay, we have investigated several compounds, including synthetic chemicals and phytoestrogens, for aromatase inhibition. The phytoestrogens, except genistein, were aromatase inhibitors at low concentrations (< 1 micro M) but estrogenic at higher concentrations (greater than or equal to 1 micro M), resulting in U-shaped dose-response curves. None of the tested synthetic chemicals were aromatase inhibitors. The low-dose aromatase inhibition distinguished phytoestrogens from other estrogenic compounds and may partly explain reports about antiestrogenic properties of phytoestrogens. Aromatase inhibition may play an important role in the protective effects of phytoestrogens against breast cancer. PMID:12153753

  12. Statistical analysis of aquifer-test results for nine regional aquifers in Louisiana

    USGS Publications Warehouse

    Martin, Angel; Early, D.A.

    1987-01-01

    This report, prepared as part of the Gulf Coast Regional Aquifer-System Analysis project, presents a compilation, summarization, and statistical analysis of aquifer-test results for nine regional aquifers in Louisiana. These are from youngest to oldest: The alluvial, Pleistocene, Evangeline, Jasper, Catahoula, Cockfield, Sparta, Carrizo, and Wilcox aquifers. Approximately 1,500 aquifer tests in U.S. Geological Survey files in Louisiana were examined and 1,001 were input to a computer file. Analysis of the aquifer test results and plots that describe aquifer hydraulic characteristics were made for each regional aquifer. Results indicate that, on the average, permeability (hydraulic conductivity) generally tends to decrease from the youngest aquifers to the oldest. The most permeable aquifers in Louisiana are the alluvial and Pleistocene aquifers; whereas, the least permeable are the Carrizo and Wilcox aquifers. (Author 's abstract)

  13. Slowing the increase in the population dose resulting from CT scans.

    PubMed

    Brenner, D J

    2010-12-01

    The annual number of CT scans in the U.S. is now over 70 million. The concern is that organ doses from CT are typically far larger than those from conventional X-ray examinations, and there is epidemiological evidence of a small but significant increased cancer risk at typical CT doses. Because CT is a superb diagnostic tool and because individual CT risks are small, when a CT scan is clinically indicated, the CT benefit/risk balance is by far in the patient's favor. Nevertheless, CT should operate under the ALARA (As Low As Reasonably Achievable) principle, and opportunities exist to reduce the significant population dose associated with CT without compromising patient care. The first opportunity is to reduce the dose per scan, and improved technology has much potential here. The second opportunity is selective replacement of CT with other modalities, such as for many head and spinal examinations (with MRI), and for diagnosing appendicitis (selective use of ultrasound + CT). Finally, a fraction of CT scans could be avoided entirely, as indicated by CT decision rules: Clinical decision rules for CT use represent a powerful approach for slowing down the increase in CT use, because they have the potential to overcome some of the major factors that result in some CT scans being undertaken when they are potentially not clinically helpful. In the U.S. and potentially elsewhere, legislative approaches are a possible option, to improve quality control and reduce clinically unneeded CT use, and it is also possible that upcoming changes in heath care economics will tend to slow the increase in such CT use.

  14. Parameter sampling capabilities of sequential and simultaneous data assimilation: II. Statistical analysis of numerical results

    NASA Astrophysics Data System (ADS)

    Fossum, Kristian; Mannseth, Trond

    2014-11-01

    We assess and compare parameter sampling capabilities of one sequential and one simultaneous Bayesian, ensemble-based, joint state-parameter (JS) estimation method. In the companion paper, part I (Fossum and Mannseth 2014 Inverse Problems 30 114002), analytical investigations lead us to propose three claims, essentially stating that the sequential method can be expected to outperform the simultaneous method for weakly nonlinear forward models. Here, we assess the reliability and robustness of these claims through statistical analysis of results from a range of numerical experiments. Samples generated by the two approximate JS methods are compared to samples from the posterior distribution generated by a Markov chain Monte Carlo method, using four approximate measures of distance between probability distributions. Forward-model nonlinearity is assessed from a stochastic nonlinearity measure allowing for sufficiently large model dimensions. Both toy models (with low computational complexity, and where the nonlinearity is fairly easy to control) and two-phase porous-media flow models (corresponding to down-scaled versions of problems to which the JS methods have been frequently applied recently) are considered in the numerical experiments. Results from the statistical analysis show strong support of all three claims stated in part I.

  15. Error statistics of hidden Markov model and hidden Boltzmann model results

    PubMed Central

    Newberg, Lee A

    2009-01-01

    Background Hidden Markov models and hidden Boltzmann models are employed in computational biology and a variety of other scientific fields for a variety of analyses of sequential data. Whether the associated algorithms are used to compute an actual probability or, more generally, an odds ratio or some other score, a frequent requirement is that the error statistics of a given score be known. What is the chance that random data would achieve that score or better? What is the chance that a real signal would achieve a given score threshold? Results Here we present a novel general approach to estimating these false positive and true positive rates that is significantly more efficient than are existing general approaches. We validate the technique via an implementation within the HMMER 3.0 package, which scans DNA or protein sequence databases for patterns of interest, using a profile-HMM. Conclusion The new approach is faster than general naïve sampling approaches, and more general than other current approaches. It provides an efficient mechanism by which to estimate error statistics for hidden Markov model and hidden Boltzmann model results. PMID:19589158

  16. Statistical analysis of real-time, enviromental radon monitoring results at the Fernald Enviromental Management Project

    SciTech Connect

    Liu, Ning; Spitz, H.B.; Tomezak, L.

    1996-02-01

    A comprehensive real-time, environmental radon monitoring program is being conducted at the Fernald Environmental Management Project, where a large quantity of radium-bearing residues have been stored in two covered earth-bermed silos. Statistical analyses was conducted to determine what impact radon emitted by the radium bearing materials contained in the silos has on the ambient radon concentration at the Fernald Environmental Management Project site. The distribution that best describes the outdoor radon monitoring data was determined before statistical analyses were conducted. Random effects associated with the selection of radon monitoring locations were accommodated by using nested and nested factorial classification models. The Project site was divided into four general areas according to their characteristics and functions: (1) the silo area, where the radium-bearing waste is stored; (2) the production/administration area; (3) the perimeter area, or fence-line, of the Fernald Environmental Management Project site; and (4) a background area, located approximately 13 km from the Fernald Environmental Management Project site, representing the naturally-occurring radon concentration. A total of 15 continuous, hourly readout radon monitors were installed to measure the outdoor radon concentration. Measurement results from each individual monitor were found to be log-normally distributed. A series of contrast tests, which take random effects into account, were performed to compare the radon concentration between different areas of the site. These comparisons demonstrate that the radon concentrations in the production/administration area and the perimeter area are statistically equal to the natural background, whereas the silo area is significantly higher than background. The study also showed that the radon concentration in the silo area was significantly reduced after a sealant barrier was applied to the contents of the silos. 10 refs., 6 figs., 8 tabs.

  17. Teachers' Statistical Problem Solving with Dynamic Technology: Research Results across Multiple Institutions

    ERIC Educational Resources Information Center

    Lee, Hollylynne Stohl; Kersaint, Gladis; Harper, Suzanne; Driskell, Shannon O.; Leatham, Keith R.

    2012-01-01

    This study examined a random stratified sample (n = 62) of prospective teachers' work across eight institutions on three tasks that utilized dynamic statistical software. The authors considered how teachers utilized their statistical knowledge and technological statistical knowledge to engage in cycles of investigation. This paper characterizes…

  18. Teachers' Statistical Problem Solving with Dynamic Technology: Research Results across Multiple Institutions

    ERIC Educational Resources Information Center

    Lee, Hollylynne Stohl; Kersaint, Gladis; Harper, Suzanne; Driskell, Shannon O.; Leatham, Keith R.

    2012-01-01

    This study examined a random stratified sample (n = 62) of prospective teachers' work across eight institutions on three tasks that utilized dynamic statistical software. The authors considered how teachers utilized their statistical knowledge and technological statistical knowledge to engage in cycles of investigation. This paper characterizes…

  19. Statistical model based iterative reconstruction in clinical CT systems. Part III. Task-based kV/mAs optimization for radiation dose reduction

    PubMed Central

    Li, Ke; Gomez-Cardona, Daniel; Hsieh, Jiang; Lubner, Meghan G.; Pickhardt, Perry J.; Chen, Guang-Hong

    2015-01-01

    Purpose: For a given imaging task and patient size, the optimal selection of x-ray tube potential (kV) and tube current-rotation time product (mAs) is pivotal in achieving the maximal radiation dose reduction while maintaining the needed diagnostic performance. Although contrast-to-noise (CNR)-based strategies can be used to optimize kV/mAs for computed tomography (CT) imaging systems employing the linear filtered backprojection (FBP) reconstruction method, a more general framework needs to be developed for systems using the nonlinear statistical model-based iterative reconstruction (MBIR) method. The purpose of this paper is to present such a unified framework for the optimization of kV/mAs selection for both FBP- and MBIR-based CT systems. Methods: The optimal selection of kV and mAs was formulated as a constrained optimization problem to minimize the objective function, Dose(kV,mAs), under the constraint that the achievable detectability index d′(kV,mAs) is not lower than the prescribed value of d℞′ for a given imaging task. Since it is difficult to analytically model the dependence of d′ on kV and mAs for the highly nonlinear MBIR method, this constrained optimization problem is solved with comprehensive measurements of Dose(kV,mAs) and d′(kV,mAs) at a variety of kV–mAs combinations, after which the overlay of the dose contours and d′ contours is used to graphically determine the optimal kV–mAs combination to achieve the lowest dose while maintaining the needed detectability for the given imaging task. As an example, d′ for a 17 mm hypoattenuating liver lesion detection task was experimentally measured with an anthropomorphic abdominal phantom at four tube potentials (80, 100, 120, and 140 kV) and fifteen mA levels (25 and 50–700) with a sampling interval of 50 mA at a fixed rotation time of 0.5 s, which corresponded to a dose (CTDIvol) range of [0.6, 70] mGy. Using the proposed method, the optimal kV and mA that minimized dose for the

  20. Standard and reduced radiation dose liver CT images: adaptive statistical iterative reconstruction versus model-based iterative reconstruction-comparison of findings and image quality.

    PubMed

    Shuman, William P; Chan, Keith T; Busey, Janet M; Mitsumori, Lee M; Choi, Eunice; Koprowicz, Kent M; Kanal, Kalpana M

    2014-12-01

    To investigate whether reduced radiation dose liver computed tomography (CT) images reconstructed with model-based iterative reconstruction ( MBIR model-based iterative reconstruction ) might compromise depiction of clinically relevant findings or might have decreased image quality when compared with clinical standard radiation dose CT images reconstructed with adaptive statistical iterative reconstruction ( ASIR adaptive statistical iterative reconstruction ). With institutional review board approval, informed consent, and HIPAA compliance, 50 patients (39 men, 11 women) were prospectively included who underwent liver CT. After a portal venous pass with ASIR adaptive statistical iterative reconstruction images, a 60% reduced radiation dose pass was added with MBIR model-based iterative reconstruction images. One reviewer scored ASIR adaptive statistical iterative reconstruction image quality and marked findings. Two additional independent reviewers noted whether marked findings were present on MBIR model-based iterative reconstruction images and assigned scores for relative conspicuity, spatial resolution, image noise, and image quality. Liver and aorta Hounsfield units and image noise were measured. Volume CT dose index and size-specific dose estimate ( SSDE size-specific dose estimate ) were recorded. Qualitative reviewer scores were summarized. Formal statistical inference for signal-to-noise ratio ( SNR signal-to-noise ratio ), contrast-to-noise ratio ( CNR contrast-to-noise ratio ), volume CT dose index, and SSDE size-specific dose estimate was made (paired t tests), with Bonferroni adjustment. Two independent reviewers identified all 136 ASIR adaptive statistical iterative reconstruction image findings (n = 272) on MBIR model-based iterative reconstruction images, scoring them as equal or better for conspicuity, spatial resolution, and image noise in 94.1% (256 of 272), 96.7% (263 of 272), and 99.3% (270 of 272), respectively. In 50 image sets, two reviewers

  1. Statistical model based iterative reconstruction in clinical CT systems. Part III. Task-based kV/mAs optimization for radiation dose reduction.

    PubMed

    Li, Ke; Gomez-Cardona, Daniel; Hsieh, Jiang; Lubner, Meghan G; Pickhardt, Perry J; Chen, Guang-Hong

    2015-09-01

    For a given imaging task and patient size, the optimal selection of x-ray tube potential (kV) and tube current-rotation time product (mAs) is pivotal in achieving the maximal radiation dose reduction while maintaining the needed diagnostic performance. Although contrast-to-noise (CNR)-based strategies can be used to optimize kV/mAs for computed tomography (CT) imaging systems employing the linear filtered backprojection (FBP) reconstruction method, a more general framework needs to be developed for systems using the nonlinear statistical model-based iterative reconstruction (MBIR) method. The purpose of this paper is to present such a unified framework for the optimization of kV/mAs selection for both FBP- and MBIR-based CT systems. The optimal selection of kV and mAs was formulated as a constrained optimization problem to minimize the objective function, Dose(kV,mAs), under the constraint that the achievable detectability index d'(kV,mAs) is not lower than the prescribed value of d'R for a given imaging task. Since it is difficult to analytically model the dependence of d' on kV and mAs for the highly nonlinear MBIR method, this constrained optimization problem is solved with comprehensive measurements of Dose(kV,mAs) and d'(kV,mAs) at a variety of kV-mAs combinations, after which the overlay of the dose contours and d' contours is used to graphically determine the optimal kV-mAs combination to achieve the lowest dose while maintaining the needed detectability for the given imaging task. As an example, d' for a 17 mm hypoattenuating liver lesion detection task was experimentally measured with an anthropomorphic abdominal phantom at four tube potentials (80, 100, 120, and 140 kV) and fifteen mA levels (25 and 50-700) with a sampling interval of 50 mA at a fixed rotation time of 0.5 s, which corresponded to a dose (CTDIvol) range of [0.6, 70] mGy. Using the proposed method, the optimal kV and mA that minimized dose for the prescribed detectability level of d'R=16

  2. Determination of errors in derived magnetic field directions in geosynchronous orbit: results from a statistical approach

    DOE PAGES

    Chen, Yue; Cunningham, Gregory; Henderson, Michael

    2016-09-21

    This study aims to statistically estimate the errors in local magnetic field directions that are derived from electron directional distributions measured by Los Alamos National Laboratory geosynchronous (LANL GEO) satellites. First, by comparing derived and measured magnetic field directions along the GEO orbit to those calculated from three selected empirical global magnetic field models (including a static Olson and Pfitzer 1977 quiet magnetic field model, a simple dynamic Tsyganenko 1989 model, and a sophisticated dynamic Tsyganenko 2001 storm model), it is shown that the errors in both derived and modeled directions are at least comparable. Second, using a newly developedmore » proxy method as well as comparing results from empirical models, we are able to provide for the first time circumstantial evidence showing that derived magnetic field directions should statistically match the real magnetic directions better, with averaged errors  < ∼ 2°, than those from the three empirical models with averaged errors  > ∼ 5°. In addition, our results suggest that the errors in derived magnetic field directions do not depend much on magnetospheric activity, in contrast to the empirical field models. Finally, as applications of the above conclusions, we show examples of electron pitch angle distributions observed by LANL GEO and also take the derived magnetic field directions as the real ones so as to test the performance of empirical field models along the GEO orbits, with results suggesting dependence on solar cycles as well as satellite locations. This study demonstrates the validity and value of the method that infers local magnetic field directions from particle spin-resolved distributions.« less

  3. ENVISAT ASAR satellite offshore wind resource statistics in Iceland compared to NORA10 model results

    NASA Astrophysics Data System (ADS)

    Bay Hasager, Charlotte; Badger, Merete; Rugaard Furevik, Birgitte; Nawri, Nikolai; Nína Petersen, Guðrún; Björnsson, Halldór; Ferhat Bingol, Ferhat; Clausen, Niels-Erik

    2014-05-01

    In Iceland the offshore regions have been investigated from satellite images from the Envisat Advanced Synthetic Aperture Radar (SAR) from the European Space Agency. The data have been retrieved from 2002 to 2012. Each satellite image has been calibrated and thereafter the CMOD5.N geophysical model function has been used to calculate the wind speed. Each resulting pixel is 1 km by 1 km. The wind direction is taken from the US Navy Operational Global Atmospheric Prediction System (NOGAPS) model. It has much lower spatial resolution and therefore the model wind directions are interpolated in space and time before performing the SAR-based wind retrieval. In total 2,500 images have been processed. This results in average 300 overlapping images. More data were available in the northern part of Iceland; therefore the number of overlapping samples is around 400 here and only 200 at the southern coast. The wind resource statistics of mean wind speed, Weibull scale and shape parameters and energy density have been calculated using the Satellite-WAsP (S-WAsP) program. The coastline of Iceland is complex. The individual wind maps from SAR reveal a multitude of atmospheric phenomena including lee effects and gap flows in the fjords. The wind resource statistics shows the mean wind speed to range from 5 to 8 m/s at 10 m height above the sea level. Selected case study areas are being defined for further investigation. SAR-derived wind maps have the advantage of covering the coastal zone. Further offshore the SAR-derived winds will be compared to the NORA10 atmospheric model results and scatterometer winds. In Iceland the wind resources on land are promising for wind energy application but it is not yet exploited. The study on the offshore wind resource is useful as pre-feasibility in case this clean energy resource is to be exploited at a later stage. The work is part of the Nordic Icewind project.

  4. Determination of errors in derived magnetic field directions in geosynchronous orbit: results from a statistical approach

    NASA Astrophysics Data System (ADS)

    Chen, Yue; Cunningham, Gregory; Henderson, Michael

    2016-09-01

    This study aims to statistically estimate the errors in local magnetic field directions that are derived from electron directional distributions measured by Los Alamos National Laboratory geosynchronous (LANL GEO) satellites. First, by comparing derived and measured magnetic field directions along the GEO orbit to those calculated from three selected empirical global magnetic field models (including a static Olson and Pfitzer 1977 quiet magnetic field model, a simple dynamic Tsyganenko 1989 model, and a sophisticated dynamic Tsyganenko 2001 storm model), it is shown that the errors in both derived and modeled directions are at least comparable. Second, using a newly developed proxy method as well as comparing results from empirical models, we are able to provide for the first time circumstantial evidence showing that derived magnetic field directions should statistically match the real magnetic directions better, with averaged errors < ˜ 2°, than those from the three empirical models with averaged errors > ˜ 5°. In addition, our results suggest that the errors in derived magnetic field directions do not depend much on magnetospheric activity, in contrast to the empirical field models. Finally, as applications of the above conclusions, we show examples of electron pitch angle distributions observed by LANL GEO and also take the derived magnetic field directions as the real ones so as to test the performance of empirical field models along the GEO orbits, with results suggesting dependence on solar cycles as well as satellite locations. This study demonstrates the validity and value of the method that infers local magnetic field directions from particle spin-resolved distributions.

  5. Exact statistical results for binary mixing and reaction in variable density turbulence

    NASA Astrophysics Data System (ADS)

    Ristorcelli, J. R.

    2017-02-01

    We report a number of rigorous statistical results on binary active scalar mixing in variable density turbulence. The study is motivated by mixing between pure fluids with very different densities and whose density intensity is of order unity. Our primary focus is the derivation of exact mathematical results for mixing in variable density turbulence and we do point out the potential fields of application of the results. A binary one step reaction is invoked to derive a metric to asses the state of mixing. The mean reaction rate in variable density turbulent mixing can be expressed, in closed form, using the first order Favre mean variables and the Reynolds averaged density variance, ⟨ρ2⟩ . We show that the normalized density variance, ⟨ρ2⟩ , reflects the reduction of the reaction due to mixing and is a mix metric. The result is mathematically rigorous. The result is the variable density analog, the normalized mass fraction variance ⟨c2⟩ used in constant density turbulent mixing. As a consequence, we demonstrate that use of the analogous normalized Favre variance of the mass fraction, c″ ⁣2˜ , as a mix metric is not theoretically justified in variable density turbulence. We additionally derive expressions relating various second order moments of the mass fraction, specific volume, and density fields. The central role of the density specific volume covariance ⟨ρ v ⟩ is highlighted; it is a key quantity with considerable dynamical significance linking various second order statistics. For laboratory experiments, we have developed exact relations between the Reynolds scalar variance ⟨c2⟩ its Favre analog c″ ⁣2˜ , and various second moments including ⟨ρ v ⟩ . For moment closure models that evolve ⟨ρ v ⟩ and not ⟨ρ2⟩ , we provide a novel expression for ⟨ρ2⟩ in terms of a rational function of ⟨ρ v ⟩ that avoids recourse to Taylor series methods (which do not converge for large density differences). We have derived

  6. Statistical analysis of the inherent variability in the results of evolutionary debris models

    NASA Astrophysics Data System (ADS)

    Lidtke, Aleksander A.; Lewis, Hugh G.; Armellin, Roberto

    2017-04-01

    Space debris simulations, e.g. those performed by the Inter-Agency Debris Coordination Committee (Liou et al., 2013), showed that the number of objects in orbit is likely to increase. This study analyses the uncertainty in the results of space debris simulations performed using semi-stochastic models that necessitate the use of Monte Carlo simulations, which are often used by the Inter-Agency Debris Coordination Committee, amongst other studies. Statistics of the possible numbers of objects in orbit and collisions over the next 200 years are generated for the ;mitigation only; scenario using a sample of 25,000 Monte Carlo runs. Bootstraps on the mean, median, variance, skewness and kurtosis of these distributions are performed. It is shown that the distribution of the objects predicted to be on-orbit becomes log-normal as collisions occur, and that Monte Carlo samples larger than traditionally used are needed to capture the debris simulation uncertainty.

  7. Statistical Analysis of Deflation in Covariance and Resultant Pc Values for AQUA, AURA and TERRA

    NASA Technical Reports Server (NTRS)

    Hasan, Syed O.

    2016-01-01

    This presentation will display statistical analysis performed for raw conjunction CDMs received for the EOS Aqua, Aura and Terra satellites within the period of February 2015 through July 2016. The analysis performed indicates a discernable deflation in covariance calculated at the JSpOC after the utilization of the dynamic drag consider parameter was implemented operationally in May 2015. As a result, the overall diminution in the conjunction plane intersection of the primary and secondary objects appears to be leading to reduced probability of collision (Pc) values for these conjunction events. This presentation also displays evidence for this theory with analysis of Pc trending plots using data calculated by the SpaceNav CRMS system.

  8. Convergence and shear statistics in galaxy clusters as a result of Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Poplavsky, Alexander

    2016-03-01

    In this paper the influence of galaxy cluster halo environment on the deflection properties of its galaxies is investigated. For this purpose circular and elliptical projected cluster haloes obeying Einasto density profiles are modelled in the \\varLambdaCDM cosmological model. By Monte-Carlo simulations external shear and convergence are calculated for random positions of a test galaxy within its cluster. Throughout the simulations the total virial mass, profile concentration and slope parameters are varied both for cluster and its galaxies. The cluster is composed of smooth matter distribution (intergalactic gas and dark matter) and randomly placed galaxies. As a result of multiple simulation runs robust statistical estimations of external shear and convergence are derived for variable cluster characteristics and its redshift. In addition, the models for external shear and convergence are applied for the galaxy lens seen through the cluster IRC-0218.

  9. 42 CFR 82.26 - How will NIOSH report dose reconstruction results?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES METHODS FOR CONDUCTING DOSE RECONSTRUCTION UNDER... dose reconstruction, justification for the decision, and if possible, a quantitative estimate of the... information and methods applied to produce the dose reconstruction estimates, including any factual findings...

  10. DYNAMIC STABILITY OF THE SOLAR SYSTEM: STATISTICALLY INCONCLUSIVE RESULTS FROM ENSEMBLE INTEGRATIONS

    SciTech Connect

    Zeebe, Richard E.

    2015-01-01

    Due to the chaotic nature of the solar system, the question of its long-term stability can only be answered in a statistical sense, for instance, based on numerical ensemble integrations of nearby orbits. Destabilization of the inner planets, leading to close encounters and/or collisions can be initiated through a large increase in Mercury's eccentricity, with a currently assumed likelihood of ∼1%. However, little is known at present about the robustness of this number. Here I report ensemble integrations of the full equations of motion of the eight planets and Pluto over 5 Gyr, including contributions from general relativity. The results show that different numerical algorithms lead to statistically different results for the evolution of Mercury's eccentricity (e{sub M}). For instance, starting at present initial conditions (e{sub M}≃0.21), Mercury's maximum eccentricity achieved over 5 Gyr is, on average, significantly higher in symplectic ensemble integrations using heliocentric rather than Jacobi coordinates and stricter error control. In contrast, starting at a possible future configuration (e{sub M}≃0.53), Mercury's maximum eccentricity achieved over the subsequent 500 Myr is, on average, significantly lower using heliocentric rather than Jacobi coordinates. For example, the probability for e{sub M} to increase beyond 0.53 over 500 Myr is >90% (Jacobi) versus only 40%-55% (heliocentric). This poses a dilemma because the physical evolution of the real system—and its probabilistic behavior—cannot depend on the coordinate system or the numerical algorithm chosen to describe it. Some tests of the numerical algorithms suggest that symplectic integrators using heliocentric coordinates underestimate the odds for destabilization of Mercury's orbit at high initial e{sub M}.

  11. Compendium of Current Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

    NASA Technical Reports Server (NTRS)

    Cochran, Donna J.; O'Bryan, Martha V.; Buchner, Stephen P.; Poivey, Christian; Ladbury, Ray L.; LaBel, Kenneth A.

    2007-01-01

    Sensitivity of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage is studied. Devices tested include optoelectronics, digital, analog, linear bipolar devices, and hybrid devices.

  12. Evaluation of a statistics-based Ames mutagenicity QSAR model and interpretation of the results obtained.

    PubMed

    Barber, Chris; Cayley, Alex; Hanser, Thierry; Harding, Alex; Heghes, Crina; Vessey, Jonathan D; Werner, Stephane; Weiner, Sandy K; Wichard, Joerg; Giddings, Amanda; Glowienke, Susanne; Parenty, Alexis; Brigo, Alessandro; Spirkl, Hans-Peter; Amberg, Alexander; Kemper, Ray; Greene, Nigel

    2016-04-01

    The relative wealth of bacterial mutagenicity data available in the public literature means that in silico quantitative/qualitative structure activity relationship (QSAR) systems can readily be built for this endpoint. A good means of evaluating the performance of such systems is to use private unpublished data sets, which generally represent a more distinct chemical space than publicly available test sets and, as a result, provide a greater challenge to the model. However, raw performance metrics should not be the only factor considered when judging this type of software since expert interpretation of the results obtained may allow for further improvements in predictivity. Enough information should be provided by a QSAR to allow the user to make general, scientifically-based arguments in order to assess and overrule predictions when necessary. With all this in mind, we sought to validate the performance of the statistics-based in vitro bacterial mutagenicity prediction system Sarah Nexus (version 1.1) against private test data sets supplied by nine different pharmaceutical companies. The results of these evaluations were then analysed in order to identify findings presented by the model which would be useful for the user to take into consideration when interpreting the results and making their final decision about the mutagenic potential of a given compound. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Results of dose sensors measurements in the middle-Earth orbit for the period of 2009-2015

    NASA Astrophysics Data System (ADS)

    Protopopov, Grigory; Shatov, Pavel; Tasenko, Sergey; Lyakhov, Igor; Makarova, Nina; Balashov, Sergey; Sitnikova, Ninel

    2016-07-01

    The measurements results of space radiation exposure on electronic components carried out by dose sensors are presented in the paper. Dose sensors operate on metal-nitride-oxide-semiconductor dosimetry pricniple. The flight data have been receiving for more than 6 years. The measurements results are compared with others flight data on different orbits. The analysis of the received data from 2009 to 2015 allows us to find out the periods with sharp increase of dose rate and to define values of such increases. We had analyzed space radiation characteristics data from other monitoring systems (such as GOES, Electro-L) in dates of dose rate sharp increase. Results of the analysis of dose rate increase, which had been fixed by TID sensors in 2015, will be presented in full paper. We had calculated average dose rates for different space models in the middle-Earth orbit (AE8, AE9 and others) and determined the most relevant models to the experimental data (with account for relaxation effect of dose sensor outputs). The comparison results for different models will be presented in the full paper. We had used different approaches for simulating of dose sensors shielding geometry, such as semi-sphere, semi-infinite plate, sector analysis, with taking account of different shielding elements. The analysis results of shielding configuration influence on calculated values of dose rate will be presented in the full paper.

  14. Statistical Results on Filtering and Epi-convergence for Learning-Based Model Predictive Control

    DTIC Science & Technology

    2011-12-17

    be described by ordinary differential equations (ODE’s). The second part provides proofs concerning the epi-convergence of different statistical...and statistical identi cation (or learning) of unmodeled dynamics, for dynamical systems that can be described by ordinary di erential equations (ODE’s... differential equations (ODE’s). The second part is found in Section 4 and pro- vides proofs concerning the epi-convergence of different statistical

  15. Vigabatrin pediatric dosing information for refractory complex partial seizures: results from a population dose-response analysis.

    PubMed

    Nielsen, Jace C; Tolbert, Dwain; Patel, Mahlaqa; Kowalski, Kenneth G; Wesche, David L

    2014-12-01

    We predicted vigabatrin dosages for adjunctive therapy for pediatric patients with refractory complex partial seizures (rCPS) that would produce efficacy comparable to that observed for approved adult dosages. A dose-response model related seizure-count data to vigabatrin dosage to identify dosages for pediatric rCPS patients. Seizure-count data were obtained from three pediatric and two adult rCPS clinical trials. Dosages were predicted for oral solution and tablet formulations. Predicted oral solution dosages to achieve efficacy comparable to that of a 1 g/day adult dosage were 350 and 450 mg/day for patients with body weight ranges 10-15 and >15-20 kg, respectively. Predicted oral solution dosages for efficacy comparable to a 3 g/day adult dosage were 1,050 and 1,300 mg/day for weight ranges 10-15 and >15-20 kg, respectively. Predicted tablet dosage for efficacy comparable to a 1 g/day adult dosage was 500 mg/day for weight ranges 25-60 kg. Predicted tablet dosage for efficacy comparable to a 3 g/day adult dosage was 2,000 mg for weight ranges 25-60 kg. Vigabatrin dosages were identified for pediatric rCPS patients with body weights ≥10 kg.

  16. Dose Escalation and Quality of Life in Patients With Localized Prostate Cancer Treated With Radiotherapy: Long-Term Results of the Dutch Randomized Dose-Escalation Trial (CKTO 96-10 Trial)

    SciTech Connect

    Al-Mamgani, Abrahim; Putten, Wim L.J. van; Wielen, Gerard J. van der; Levendag, Peter C.; Incrocci, Luca

    2011-03-15

    Purpose: To assess the impact of dose escalation of radiotherapy on quality of life (QoL) in prostate cancer patients. Patients and Methods: Three hundred prostate cancer patients participating in the Dutch randomized trial (CKTO 69-10) comparing 68 Gy with 78 Gy were the subject of this analysis. These patients filled out the SF-36 QoL questionnaire before radiotherapy (baseline) and 6, 12, 24, and 36 months thereafter. Changes in QoL over time of {>=}10 points were considered clinically relevant. Repeated-measures regression analyses were applied to estimate and test the QoL changes over time, the differences between the two arms, and for association with a number of covariates. Results: At 3-year follow-up, the summary score physical health was 73.2 for the 68-Gy arm vs. 71.6 for the 78-Gy arm (p = 0.81), and the summary score mental health was 76.7 for the 68-Gy arm vs. 76.1 for the 78-Gy arm (p = 0.97). Statistically significant (p < 0.01) deterioration in QoL scores over time was registered in both arms in six scales. The deterioration over time was more pronounced in the high-dose arm for most scales. However, clinically relevant deterioration (>10 points) was seen for only two scales. None of the tested covariates were significantly correlated with QoL scores. Conclusion: Dose escalation did not result in significant deterioration of QoL in prostate cancer patients. In both randomization arms, statistically significant decreases in QoL scores over time were seen in six scales. The deterioration of QoL was more pronounced in the physical than in the mental health domain and in some scales more in the high- than in the low-dose arm, but the differences between arms were not statistically significant.

  17. Statistical analyses of the U.S. Air Force Bioventing Initiative results

    SciTech Connect

    Leeson, A.; Kumar, P.; Hinchee, R.E.; Downey, D.; Vogel, C.M.; Sayles, G.D.; Miller, R.N.

    1995-12-31

    The US Air Force`s Bioventing Initiative has involved conducting field treatability studies to evaluate bioventing feasibility at more than 120 sites throughout the US. At those sites where feasibility studies produced positive results, pilot-scale bioventing systems were installed and operated for 1 year. The results from the pilot-scale bioventing systems have been used to develop a large database from which to determine the most important parameters to be used in evaluating whether to implement bioventing. Data generated from the Bioventing Initiative were subjected to a thorough statistical analysis to determine which parameters correlate with BTEX and TPH biodegradation rates. The study involved in situ respiration test data, soil gas permeability test data, and soil chemistry and nutrient data from each site. Results from the Bioventing Initiative demonstrated that some biodegradation occurred at virtually all sites regardless of site conditions. Data collected from the sites demonstrate that even sites with low nutrient levels exhibit significant microbial activity and will therefore respond well to bioventing.

  18. Effect of altitude on physiological performance: a statistical analysis using results of international football games

    PubMed Central

    2007-01-01

    Objective To assess the effect of altitude on match results and physiological performance of a large and diverse population of professional athletes. Design Statistical analysis of international football (soccer) scores and results. Data resources FIFA extensive database of 1460 football matches in 10 countries spanning over 100 years. Results Altitude had a significant (P<0.001) negative impact on physiological performance as revealed through the overall underperformance of low altitude teams when playing against high altitude teams in South America. High altitude teams score more and concede fewer goals with increasing altitude difference. Each additional 1000 m of altitude difference increases the goal difference by about half of a goal. The probability of the home team winning for two teams from the same altitude is 0.537, whereas this rises to 0.825 for a home team with an altitude difference of 3695 m (such as Bolivia v Brazil) and falls to 0.213 when the altitude difference is −3695 m (such as Brazil v Bolivia). Conclusions Altitude provides a significant advantage for high altitude teams when playing international football games at both low and high altitudes. Lowland teams are unable to acclimatise to high altitude, reducing physiological performance. As physiological performance does not protect against the effect of altitude, better predictors of individual susceptibility to altitude illness would facilitate team selection. PMID:18156225

  19. High-dose-rate brachytherapy for intranasal tumours in dogs: results of a pilot study.

    PubMed

    Klueter, S; Krastel, D; Ludewig, E; Reischauer, A; Heinicke, F; Pohlmann, S; Wolf, U; Grevel, V; Hildebrandt, G

    2006-12-01

    This prospective study describes the feasibility and toxicity of (192)Iridium high-dose-rate (HDR) brachytherapy as an alternative strategy for the treatment of canine intranasal tumours. Fifteen dogs with malignant intranasal tumours were treated twice weekly using a hypofractionated protocol with eight fractions, 5 Gy per fraction, resulting in a total dose of 40 Gy. Acute and chronic adverse side-effects appeared to be rare. Only 7% of the acute side-effects and 5% of the chronic were classified as severe (grade 3). Eight dogs showed clinical complete remission, and five dogs had partial remission, with a resolution of tumour-related symptoms. Magnetic resonance imaging showed a reduced tumour mass in 12 cases. Median survival time was 17 months (range 4-48 months), with four dogs (three without disease) still alive. Median time to recurrence of these dogs was 14 months. In nine dogs, progression or recurrence of the tumour was the cause of death. This study suggests that HDR brachytherapy is feasible and well tolerated.

  20. Exhaling a budesonide inhaler through the nose results in a significant reduction in dose requirement of budesonide nasal spray in patients having asthma with rhinitis.

    PubMed

    Shaikh, W A

    1999-01-01

    Budesonide, an inhaled corticosteroid is used routinely in the treatment of bronchial asthma and rhinitis. Although inhaled corticosteroids in therapeutic doses are unlikely to result in systemic side effects, there is as yet skepticism about their routine and prolonged use. The aim of this study was to determine whether budesonide inhalation through a metered dose inhaler, when exhaled through the nose could result in a reduction in the dose requirement of budesonide metered nasal spray in patients having perennial allergic asthma with rhinitis. This study was an open, parallel, comparative, crossover trial in which 49 young patients having perennial allergic asthma with rhinitis were divided into two groups and administered either a combination of budesonide metered dose inhaler with a budesonide nasal spray or a budesonide inhaler alone, which was to be exhaled through the nose. Both groups were later crossed over and weekly symptom scores and peak nasal inspiratory flow rates were monitored during each phase of the study. Finally, patients who volunteered from both groups were instructed to note the reduction in dose requirement of budesonide nasal spray while using a budesonide inhaler and exhaling it through the nose. The results of this study reveal that when a budesonide inhaler is exhaled through the nose, it results in an improvement in symptom scores and peak nasal inspiratory flow rates, which were significantly less than those obtained in the group using both a budesonide nasal spray and a metered dose inhaler. In addition, exhaling budesonide through the nose results in a 40.1% reduction in the dose requirement of a budesonide nasal spray, which is statistically significant (p < 0.001).

  1. "What If" Analyses: Ways to Interpret Statistical Significance Test Results Using EXCEL or "R"

    ERIC Educational Resources Information Center

    Ozturk, Elif

    2012-01-01

    The present paper aims to review two motivations to conduct "what if" analyses using Excel and "R" to understand the statistical significance tests through the sample size context. "What if" analyses can be used to teach students what statistical significance tests really do and in applied research either prospectively to estimate what sample size…

  2. A guideline for reporting results of statistical analysis in Japanese Journal of Clinical Oncology.

    PubMed

    Fukuda, H; Ohashi, Y

    1997-06-01

    The paper gives guidelines to authors on the use of statistics, including statistical considerations when designing studies. Information on this article plus a list of other recommended books is available on the World Wide Web (http:/(/)wwwinfo.ncc.go.jp/jjco/) in Japanese as well as English.

  3. Interpretation of the results of statistical measurements. [search for basic probability model

    NASA Technical Reports Server (NTRS)

    Olshevskiy, V. V.

    1973-01-01

    For random processes, the calculated probability characteristic, and the measured statistical estimate are used in a quality functional, which defines the difference between the two functions. Based on the assumption that the statistical measurement procedure is organized so that the parameters for a selected model are optimized, it is shown that the interpretation of experimental research is a search for a basic probability model.

  4. Estimation of thyroid doses received by the population of Belarus as a result of the Chernobyl accident

    SciTech Connect

    Gavrilin, Y.; Khrouch, V.; Shinkarev, S.; Drozdovitch, V.; Minenko, V.; Shemyakina, E.; Bouville, A.; Anspaugh, L.

    1996-02-01

    Within weeks of the Chernobyl accident ABOUT 300,000 measurements of human thyroidal iodine-131 content were conducted in the more contaminated areas of Belarus. Results of these and other measurements form the basis of thyroid-dose reconstruction for the residents. For Class 1 (measured dose), individual doses are estimated directly from measured thyroidal iodine content plus information on life style and dietary habits. Such estimates are available for about 130,000 individuals from Gomel and Mogilev Oblasts and Minsk City. For Class 2 (passport doses), every settlement with a sufficient number of residents with measured doses, individual thyroid-dose distributions were determined for several age groups and levels of milk consumption. A population of about 2.7 million resides in the passport settlements.

  5. Statistical simulations to estimate motion-inclusive dose-volume histograms for prediction of rectal morbidity following radiotherapy.

    PubMed

    Thor, Maria; Apte, Aditya; Deasy, Joseph O; Muren, Ludvig Paul

    2013-04-01

    Internal organ motion over a course of radiotherapy (RT) leads to uncertainties in the actual delivered dose distributions. In studies predicting RT morbidity, the single estimate of the delivered dose provided by the treatment planning computed tomography (pCT) is typically assumed to be representative of the dose distribution throughout the course of RT. In this paper, a simple model for describing organ motion is introduced, and is associated to late rectal morbidity data, with the aim of improving morbidity prediction. Organ motion was described by normally distributed translational motion, with its magnitude characterised by the standard deviation (SD) of this distribution. Simulations of both isotropic and anisotropic (anterior-posterior only) motion patterns were performed, as were random, systematic or combined random and systematic motion. The associations between late rectal morbidity and motion-inclusive delivered dose-volume histograms (dDVHs) were quantified using Spearman's rank correlation coefficient (Rs) in a series of 232 prostate cancer patients, and were compared to the associations obtained with the static/planned DVH (pDVH). For both isotropic and anisotropic motion, different associations with rectal morbidity were seen with the dDVHs relative to the pDVHs. The differences were most pronounced in the mid-dose region (40-60 Gy). The associations were dependent on the applied motion patterns, with the strongest association with morbidity obtained by applying random motion with an SD in the range 0.2-0.8 cm. In this study we have introduced a simple model for describing organ motion occurring during RT. Differing and, for some cases, stronger dose-volume dependencies were found between the motion-inclusive dose distributions and rectal morbidity as compared to the associations with the planned dose distributions. This indicates that rectal organ motion during RT influences the efforts to model the risk of morbidity using planning distributions

  6. High-Dose Conformal Radiotherapy Reduces Prostate Cancer-Specific Mortality: Results of a Meta-analysis

    SciTech Connect

    Viani, Gustavo Arruda; Godoi Bernardes da Silva, Lucas; Stefano, Eduardo Jose

    2012-08-01

    Purpose: To determine in a meta-analysis whether prostate cancer-specific mortality (PCSM), biochemical or clinical failure (BCF), and overall mortality (OM) in men with localized prostate cancer treated with conformal high-dose radiotherapy (HDRT) are better than those in men treated with conventional-dose radiotherapy (CDRT). Methods and Materials: The MEDLINE, Embase, CANCERLIT, and Cochrane Library databases, as well as the proceedings of annual meetings, were systematically searched to identify randomized, controlled studies comparing conformal HDRT with CDRT for localized prostate cancer. Results: Five randomized, controlled trials (2508 patients) that met the study criteria were identified. Pooled results from these randomized, controlled trials showed a significant reduction in the incidence of PCSM and BCF rates at 5 years in patients treated with HDRT (p = 0.04 and p < 0.0001, respectively), with an absolute risk reduction (ARR) of PCSM and BCF at 5 years of 1.7% and 12.6%, respectively. Two trials evaluated PCSM with 10 years of follow up. The pooled results from these trials showed a statistical benefit for HDRT in terms of PCSM (p = 0.03). In the subgroup analysis, trials that used androgen deprivation therapy (ADT) showed an ARR for BCF of 12.9% (number needed to treat = 7.7, p < 0.00001), whereas trials without ADT had an ARR of 13.6% (number needed to treat = 7, p < 0.00001). There was no difference in the OM rate at 5 and 10 years (p = 0.99 and p = 0.11, respectively) between the groups receiving HDRT and CDRT. Conclusions: This meta-analysis is the first study to show that HDRT is superior to CDRT in preventing disease progression and prostate cancer-specific death in trials that used conformational technique to increase the total dose. Despite the limitations of our study in evaluating the role of ADT and HDRT, our data show no benefit for HDRT arms in terms of BCF in trials with or without ADT.

  7. Statistical methods for a three-period crossover design in which high dose cannot be used first.

    PubMed

    Peace, K E; Koch, G G

    1993-03-01

    Design and analysis methods for the three-period crossover trial defined by the sequences: (D0, D1, D2), (D1, D0, D2), and (D1, D2, D0), where D0 is a placebo, and D1 and D2 are a low dose and a high dose of a drug, respectively, are developed. This design may be used when investigators are unwilling to administer a higher dose of a new drug to a patient before administering a lower dose. In using this design, patients should be randomized to sequences in blocks that are integer multiples of 3. Both parametric and non-parametric analysis methods are based on contrasts that capture intrapatient variability only and provide unbiased estimates and hypothesis tests of pairwise differences between carryover, direct dose, and period effects. The design and methods are illustrated with data reflecting the cognitive component of the Alzheimer's disease assessment scale collected in a large clinical trial of Tacrine at doses of 0, 40, and 80 mg/day.

  8. Voluntarily exposure to a single, high dose of probiotic Escherichia coli results in prolonged colonisation.

    PubMed

    Wassenaar, T M; Beimfohr, C; Geske, T; Zimmermann, K

    2014-12-01

    The ability of probiotic Escherichia coli to colonise the human gut was determined in a volunteer study following national (German) regulations. Five persons voluntarily took a single, high dose of Symbioflor®2, which contains 6 different probiotic E. coli genotypes, to assess tolerance of the product, after which presence of E. coli in their faeces was tested for a follow-up period of 30 weeks. Intake of the product did not result in severe side effect in any of the individuals, though mild side effects were observed. Stool analysis showed that the probiotic E. coli had colonised all five persons for a period of 10 to 30 weeks (mean: 18.7 weeks, median: 25.7 weeks). In two individuals there was evidence of competition between host E. coli and probiotic E. coli, while in two others total E. coli levels increased persistently with at least a factor of 10 as a result of the received dose. In one individual, who had lacked detectable levels of faecal E. coli at the start of the post-authorisation safety study, long-term colonisation was established, first by probiotic E. coli exclusively, which were later replaced by host E. coli strains. In four out of five individuals, total E. coli faecal counts were higher on average than at the start of the experiment, while in none total levels exceeded 5×107 cfu/g. When the specific genotypes of the 6 probiotic E. coli were analysed, it was found that one and the same common genotype was responsible for prolonged colonisation in all five individuals.

  9. Statistical Analyses of White-Light Flares: Two Main Results about Flare Behaviour

    NASA Astrophysics Data System (ADS)

    Dal, Hasan Ali

    2012-08-01

    We present two main results, based on models and the statistical analyses of 1672 U-band flares. We also discuss the behaviour of white-light flares. In addition, the parameters of the flares detected from two years of observations on CR Dra are presented. By comparing with flare parameters obtained from other UV Ceti-type stars, we examine the behaviour of the optical flare processes along with the spectral types. Moreover, we aimed, using large white-light flare data, to analyse the flare time-scales with respect to some results obtained from X-ray observations. Using SPSS V17.0 and GraphPad Prism V5.02 software, the flares detected from CR Dra were modelled with the OPEA function, and analysed with the t-Test method to compare similar flare events in other stars. In addition, using some regression calculations in order to derive the best histograms, the time-scales of white-light flares were analysed. Firstly, CR Dra flares have revealed that white-light flares behave in a similar way as their counterparts observed in X-rays. As can be seen in X-ray observations, the electron density seems to be a dominant parameter in white-light flare process, too. Secondly, the distributions of the flare time-scales demonstrate that the number of observed flares reaches a maximum value in some particular ratios, which are 0.5, or its multiples, and especially positive integers. The thermal processes might be dominant for these white-light flares, while non-thermal processes might be dominant in the others. To obtain better results for the behaviour of the white-light flare process along with the spectral types, much more stars in a wide spectral range, from spectral type dK5e to dM6e, must be observed in white-light flare patrols.

  10. Electron attachment to SF6 under well defined conditions: comparison of statistical modeling results to experiments

    NASA Astrophysics Data System (ADS)

    Miller, T. M.; Viggiano, A. A.; Troe, J.

    2008-05-01

    Experiments were carried out using a flowing-afterglow Langmuir-probe apparatus to measure rate constants for electron attachment to SF6 and thermal detachment from SF6-. In a recent series of papers, these results were combined with new and existing data on nondissociative and dissociative attachment to SF6 and compared to statistical modeling of the various processes involved in the stabilization of the ionic products of attachment. This paper gives a summary of those findings. The major conclusions are: (a) only the ground electronic state of SF6- needs to be invoked to explain available data; (b) the electron affinity of SF6 is higher than previously thought, namely, EA(SF6) = 1.20 (± 0.05) eV; (c) the endothermicity of the dissociative electron attachment reaction that yields SF5- is 0.41 eV (± 0.05) eV at 0 K; (d) combining these two numbers gives the bond energy D0o(F—SF5-) = 1.61 (± 0.05) eV.

  11. SOLAR LIMB PROMINENCE CATCHER AND TRACKER (SLIPCAT): AN AUTOMATED SYSTEM AND ITS PRELIMINARY STATISTICAL RESULTS

    SciTech Connect

    Wang Yuming; Cao Hao; Chen Junhong; Zhang Tengfei; Yu Sijie; Zheng Huinan; Shen Chenglong; Wang, S.; Zhang Jie

    2010-07-10

    In this paper, we present an automated system, which has the capability to catch and track solar limb prominences based on observations from the extreme-ultraviolet (EUV) 304 A passband. The characteristic parameters and their evolution, including height, position angle, area, length, and brightness, are obtained without manual interventions. By applying the system to the STEREO-B/SECCHI/EUVI 304 A data during 2007 April-2009 October, we obtain a total of 9477 well-tracked prominences and a catalog of these events available online. A detailed analysis of these prominences suggests that the system has a rather good performance. We have obtained several interesting statistical results based on the catalog. Most prominences appear below the latitude of 60{sup 0} and at the height of about 26 Mm above the solar surface. Most of them are quite stable during the period they are tracked. Nevertheless, some prominences have an upward speed of more than 100 km s{sup -1}, and some others show significant downward and/or azimuthal speeds. There are strong correlations among the brightness, area, and height. The expansion of a prominence is probably one major cause of its fading during the rising or erupting process.

  12. Statistical isotropy violation in WMAP CMB maps resulting from non-circular beams

    NASA Astrophysics Data System (ADS)

    Das, Santanu; Mitra, Sanjit; Rotti, Aditya; Pant, Nidhi; Souradeep, Tarun

    2016-06-01

    Statistical isotropy (SI) of cosmic microwave background (CMB) fluctuations is a key observational test to validate the cosmological principle underlying the standard model of cosmology. While a detection of SI violation would have immense cosmological ramification, it is important to recognise their possible origin in systematic effects of observations. The WMAP seven year (WMAP-7) release claimed significant deviation from SI in the bipolar spherical harmonic (BipoSH) coefficients and . Here we present the first explicit reproduction of the measurements reported in WMAP-7, confirming that beam systematics alone can completely account for the measured SI violation. The possibility of such a systematic origin was alluded to in WMAP-7 paper itself and other authors but not as explicitly so as to account for it accurately. We simulate CMB maps using the actual WMAP non-circular beams and scanning strategy. Our estimated BipoSH spectra from these maps match the WMAP-7 results very well. It is also evident that only a very careful and adequately detailed modelling, as carried out here, can conclusively establish that the entire signal arises from non-circular beam effect. This is important since cosmic SI violation signals are expected to be subtle and dismissing a large SI violation signal as observational artefact based on simplistic plausibility arguments run the serious risk of "throwing the baby out with the bathwater".

  13. AN UPDATED CATALOG OF M33 CLUSTERS AND CANDIDATES: UBVRI PHOTOMETRY AND SOME STATISTICAL RESULTS

    SciTech Connect

    Ma Jun

    2012-08-15

    We present UBVRI photometry for 392 star clusters and candidates in the field of M33, which are selected from the most recent star cluster catalog. In this catalog, the authors listed star clusters' parameters such as cluster positions, magnitudes, colors in the UBVRIJHK{sub s} filters, and so on. However, a large fraction of objects in this catalog do not have previously published photometry. Photometry is performed using archival images from the Local Group Galaxies Survey, which covers 0.8 deg{sup 2} along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements. Positions (right ascension and declination) for some clusters are corrected here. Combined with previous literature, ours constitute a large sample of M33 star clusters. Based on this cluster sample, we present some statistical results: none of the youngest M33 clusters ({approx}10{sup 7} yr) have masses approaching 10{sup 5} M{sub Sun} ; roughly half the star clusters are consistent with the 10{sup 4}-10{sup 5} M{sub Sun} mass models; the continuous distribution of star clusters along the model line indicates that M33 star clusters have been formed continuously from the epoch of the first star cluster formation until recent times; and there are {approx}50 star clusters which are overlapped with the Galactic globular clusters on the color-color diagram, and these clusters are old globular cluster candidates in M33.

  14. Low kilovoltage peak (kVp) with an adaptive statistical iterative reconstruction algorithm in computed tomography urography: evaluation of image quality and radiation dose

    PubMed Central

    Zhou, Zhiguo; Chen, Haixi; Wei, Wei; Zhou, Shanghui; Xu, Jingbo; Wang, Xifu; Wang, Qingguo; Zhang, Guixiang; Zhang, Zhuoli; Zheng, Linfeng

    2016-01-01

    Purpose: The purpose of this study was to evaluate the image quality and radiation dose in computed tomography urography (CTU) images acquired with a low kilovoltage peak (kVp) in combination with an adaptive statistical iterative reconstruction (ASiR) algorithm. Methods: A total of 45 subjects (18 women, 27 men) who underwent CTU with kV assist software for automatic selection of the optimal kVp were included and divided into two groups (A and B) based on the kVp and image reconstruction algorithm: group A consisted of patients who underwent CTU with a 80 or 100 kVp and whose images were reconstructed with the 50% ASiR algorithm (n=32); group B consisted of patients who underwent CTU with a 120 kVp and whose images were reconstructed with the filtered back projection (FBP) algorithm (n=13). The images were separately reconstructed with volume rendering (VR) and maximum intensity projection (MIP). Finally, the image quality was evaluated using an image score, CT attenuation, image noise, the contrast-to-noise ratio (CNR) of the renal pelvis-to-abdominal visceral fat and the signal-to-noise ratio (SNR) of the renal pelvis. The radiation dose was assessed using volume CT dose index (CTDIvol), dose-length product (DLP) and effective dose (ED). Results: For groups A and B, the subjective image scores for the VR reconstruction images were 3.9±0.4 and 3.8±0.4, respectively, while those for the MIP reconstruction images were 3.8±0.4 and 3.6±0.6, respectively. No significant difference was found (p>0.05) between the two groups’ image scores for either the VR or MIP reconstruction images. Additionally, the inter-reviewer image scores did not significantly differ (p>0.05). The mean attenuation of the bilateral renal pelvis in group A was significantly higher than that in group B (271.4±57.6 vs. 221.8±35.3 HU, p<0.05), whereas the image noise in group A was significantly lower than that in group B (7.9±2.1 vs. 10.5±2.3 HU, p<0.05). The CNR and SNR in group A were

  15. Uncertainty into statistical landslide susceptibility models resulting from terrain mapping units and landslide input data

    NASA Astrophysics Data System (ADS)

    Zêzere, José Luis; Pereira, Susana; Melo, Raquel; Oliveira, Sérgio; Garcia, Ricardo

    2017-04-01

    There are multiple sources of uncertainty within statistically-based landslide susceptibility assessment that needs to be accounted and monitored. In this work we evaluate and discuss differences observed on landslide susceptibility maps resulting from the selection of the terrain mapping unit and the selection of the feature type to represent landslides (polygon vs point). The work is performed in the Silveira Basin (18.2 square kilometres) located north of Lisbon, Portugal, using a unique database of geo-environmental landslide predisposing factors and an inventory of 81 shallow translational slides. The Logistic Regression is the statistical method selected to combine the predictive factors with the dependent variable. Four landslide susceptibility models were computed using the complete landslide inventory and considering the total landslide area over four different terrain mapping units: Slope Terrain Units (STU), Geo-Hydrological Terrain Units (GHTU), Census Terrain Units (CTU) and Grid Cell Terrain Units (GCTU). Four additional landslide susceptibility models were made over the same four terrain mapping units using a landslide training group (50% of the inventory randomly selected). These models were independently validated with the other 50% of the landslide inventory (landslide test group). Lastly, two additional landslide susceptibility models were computed over GCTU, one using the landslide training group represented as point features corresponding to the centroid of landslide, and other using the centroid of landslide rupture zone. In total, 10 landslide susceptibility maps were constructed and classified in 10 classes of equal number of terrain units to allow comparison. The evaluation of the prediction skills of susceptibility models was made using ROC metrics and Success and Prediction rate curves. Lastly, the landslide susceptibility maps computed over GCTU were compared using the Kappa statistics. With this work we conclude that large differences

  16. Exploring discrepancies between quantitative validation results and the geomorphic plausibility of statistical landslide susceptibility maps

    NASA Astrophysics Data System (ADS)

    Steger, Stefan; Brenning, Alexander; Bell, Rainer; Petschko, Helene; Glade, Thomas

    2016-06-01

    Empirical models are frequently applied to produce landslide susceptibility maps for large areas. Subsequent quantitative validation results are routinely used as the primary criteria to infer the validity and applicability of the final maps or to select one of several models. This study hypothesizes that such direct deductions can be misleading. The main objective was to explore discrepancies between the predictive performance of a landslide susceptibility model and the geomorphic plausibility of subsequent landslide susceptibility maps while a particular emphasis was placed on the influence of incomplete landslide inventories on modelling and validation results. The study was conducted within the Flysch Zone of Lower Austria (1,354 km2) which is known to be highly susceptible to landslides of the slide-type movement. Sixteen susceptibility models were generated by applying two statistical classifiers (logistic regression and generalized additive model) and two machine learning techniques (random forest and support vector machine) separately for two landslide inventories of differing completeness and two predictor sets. The results were validated quantitatively by estimating the area under the receiver operating characteristic curve (AUROC) with single holdout and spatial cross-validation technique. The heuristic evaluation of the geomorphic plausibility of the final results was supported by findings of an exploratory data analysis, an estimation of odds ratios and an evaluation of the spatial structure of the final maps. The results showed that maps generated by different inventories, classifiers and predictors appeared differently while holdout validation revealed similar high predictive performances. Spatial cross-validation proved useful to expose spatially varying inconsistencies of the modelling results while additionally providing evidence for slightly overfitted machine learning-based models. However, the highest predictive performances were obtained for

  17. WE-G-18A-04: 3D Dictionary Learning Based Statistical Iterative Reconstruction for Low-Dose Cone Beam CT Imaging

    SciTech Connect

    Bai, T; Yan, H; Shi, F; Jia, X; Jiang, Steve B.; Lou, Y; Xu, Q; Mou, X

    2014-06-15

    Purpose: To develop a 3D dictionary learning based statistical reconstruction algorithm on graphic processing units (GPU), to improve the quality of low-dose cone beam CT (CBCT) imaging with high efficiency. Methods: A 3D dictionary containing 256 small volumes (atoms) of 3x3x3 voxels was trained from a high quality volume image. During reconstruction, we utilized a Cholesky decomposition based orthogonal matching pursuit algorithm to find a sparse representation on this dictionary basis of each patch in the reconstructed image, in order to regularize the image quality. To accelerate the time-consuming sparse coding in the 3D case, we implemented our algorithm in a parallel fashion by taking advantage of the tremendous computational power of GPU. Evaluations are performed based on a head-neck patient case. FDK reconstruction with full dataset of 364 projections is used as the reference. We compared the proposed 3D dictionary learning based method with a tight frame (TF) based one using a subset data of 121 projections. The image qualities under different resolutions in z-direction, with or without statistical weighting are also studied. Results: Compared to the TF-based CBCT reconstruction, our experiments indicated that 3D dictionary learning based CBCT reconstruction is able to recover finer structures, to remove more streaking artifacts, and is less susceptible to blocky artifacts. It is also observed that statistical reconstruction approach is sensitive to inconsistency between the forward and backward projection operations in parallel computing. Using high a spatial resolution along z direction helps improving the algorithm robustness. Conclusion: 3D dictionary learning based CBCT reconstruction algorithm is able to sense the structural information while suppressing noise, and hence to achieve high quality reconstruction. The GPU realization of the whole algorithm offers a significant efficiency enhancement, making this algorithm more feasible for potential

  18. SU-F-SPS-03: Direct Measurement of Organ Doses Resulting From Head and Cervical Spine Trauma CT Protocols

    SciTech Connect

    Carranza, C; Lipnharski, I; Quails, N; Correa, N; Rill, L; Arreola, M

    2016-06-15

    Purpose: This retrospective study analyzes the exposure history of emergency department (ED) patients undergoing head and cervical spine trauma computed tomography (CT) studies. This study investigated dose levels received by trauma patients and addressed any potential concerns regarding radiation dose issues. Methods: Under proper IRB approval, a cohort of 300 trauma cases of head and cervical spine trauma CT scans received in the ED was studied. The radiological image viewing software of the hospital was used to view patient images and image data. The following parameters were extracted: the imaging history of patients, the reported dose metrics from the scanner including the volumetric CT Dose Index (CTDIvol) and Dose Length Product (DLP). A postmortem subject was scanned using the same scan techniques utilized in a standard clinical head and cervical spine trauma CT protocol with 120 kVp and 280 mAs. The CTDIvol was recorded for the subject and the organ doses were measured using optically stimulated luminescent (OSL) dosimeters. Typical organ doses to the brain, thyroid, lens, salivary glands, and skin, based on the cadaver studies, were then calculated and reported for the cohort. Results: The CTDIvol reported by the CT scanner was 25.5 mGy for the postmortem subject. The average CTDIvol from the patient cohort was 34.1 mGy. From these metrics, typical average organ doses in mGy were found to be: Brain (44.57), Thyroid (33.40), Lens (82.45), Salivary Glands (61.29), Skin (47.50). The imaging history of the cohort showed that on average trauma patients received 26.1 scans over a lifetime. Conclusion: The average number of scans received on average by trauma ED patients shows that radiation doses in trauma patients may be a concern. Available dose tracking software would be helpful to track doses in trauma ED patients, highlighting the importance of minimizing unnecessary scans and keeping doses ALARA.

  19. Standard dosing of amikacin and gentamicin in critically ill patients results in variable and subtherapeutic concentrations.

    PubMed

    Roger, Claire; Nucci, Bastian; Molinari, Nicolas; Bastide, Sophie; Saissi, Gilbert; Pradel, Gael; Barbar, Saber; Aubert, Clément; Lloret, Sophie; Elotmani, Loubna; Polge, Anne; Lefrant, Jean-Yves; Roberts, Jason A; Muller, Laurent

    2015-07-01

    Low peak plasma concentrations (Cmax) of amikacin and gentamicin are reported in intensive care unit (ICU) patients after administration of the first dose. The present study aimed to describe the proportion of ICU patients in whom an adequate Cmax was achieved throughout the course of therapy. Septic ICU patients with an indication for intravenous amikacin or gentamicin were eligible for inclusion in this single-centre observational study. The first and subsequent doses and the corresponding Cmax values were recorded. The target Cmax was ≥60mg/L for amikacin and ≥30mg/L for gentamicin. Amikacin and gentamicin plasma concentrations were available in 66 and 24 patients, respectively (59±17 years; 79±19kg; height 169±12cm; SAPS II score 46±19). Pulmonary, abdominal and urinary tract infections were diagnosed in 64 patients. Culture-positive infection was confirmed in 65 patients (72%). A target first Cmax was achieved in 17/90 patients (19%). For amikacin, the target Cmax was achieved in 16/66 patients (24%) after the initial dose. In the 50 remaining patients, a change in dosing was performed in 14 patients, leading adequate peak plasma level in 2 patients. For gentamicin, the targeted Cmax was achieved in only 1/24 patient (4%) after the initial dose and was never achieved after the third dose. In conclusion, standard dosing of amikacin or gentamicin led to adequate Cmax in only 19% of patients. Subtherapeutic Cmax were not significantly corrected after subsequent doses.

  20. Can use of adaptive statistical iterative reconstruction reduce radiation dose in unenhanced head CT? An analysis of qualitative and quantitative image quality.

    PubMed

    Østerås, Bjørn Helge; Heggen, Kristin Livelten; Pedersen, Hans Kristian; Andersen, Hilde Kjernlie; Martinsen, Anne Catrine T

    2016-08-01

    Iterative reconstruction can reduce image noise and thereby facilitate dose reduction. To evaluate qualitative and quantitative image quality for full dose and dose reduced head computed tomography (CT) protocols reconstructed using filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR). Fourteen patients undergoing follow-up head CT were included. All patients underwent full dose (FD) exam and subsequent 15% dose reduced (DR) exam, reconstructed using FBP and 30% ASIR. Qualitative image quality was assessed using visual grading characteristics. Quantitative image quality was assessed using ROI measurements in cerebrospinal fluid (CSF), white matter, peripheral and central gray matter. Additionally, quantitative image quality was measured in Catphan and vendor's water phantom. There was no significant difference in qualitative image quality between FD FBP and DR ASIR. Comparing same scan FBP versus ASIR, a noise reduction of 28.6% in CSF and between -3.7 and 3.5% in brain parenchyma was observed. Comparing FD FBP versus DR ASIR, a noise reduction of 25.7% in CSF, and -7.5 and 6.3% in brain parenchyma was observed. Image contrast increased in ASIR reconstructions. Contrast-to-noise ratio was improved in DR ASIR compared to FD FBP. In phantoms, noise reduction was in the range of 3 to 28% with image content. There was no significant difference in qualitative image quality between full dose FBP and dose reduced ASIR. CNR improved in DR ASIR compared to FD FBP mostly due to increased contrast, not reduced noise. Therefore, we recommend using caution if reducing dose and applying ASIR to maintain image quality.

  1. Appropriateness of reporting statistical results in orthodontics: the dominance of P values over confidence intervals.

    PubMed

    Polychronopoulou, Argy; Pandis, Nikolaos; Eliades, Theodore

    2011-02-01

    The purpose of this study was to search the orthodontic literature and determine the frequency of reporting of confidence intervals (CIs) in orthodontic journals with an impact factor. The six latest issues of the American Journal of Orthodontics and Dentofacial Orthopedics, the European Journal of Orthodontics, and the Angle Orthodontist were hand searched and the reporting of CIs, P values, and implementation of univariate or multivariate statistical analyses were recorded. Additionally, studies were classified according to the type/design as cross-sectional, case-control, cohort, and clinical trials, and according to the subject of the study as growth/genetics, behaviour/psychology, diagnosis/treatment, and biomaterials/biomechanics. The data were analyzed using descriptive statistics followed by univariate examination of statistical associations, logistic regression, and multivariate modelling. CI reporting was very limited and was recorded in only 6 per cent of the included published studies. CI reporting was independent of journal, study area, and design. Studies that used multivariate statistical analyses had a higher probability of reporting CIs compared with those using univariate statistical analyses. Misunderstanding of the use of P values and CIs may have important implications in implementation of research findings in clinical practice.

  2. Statistical mechanics of two hard spheres in a spherical pore, exact analytic results in D dimension

    NASA Astrophysics Data System (ADS)

    Urrutia, Ignacio; Szybisz, Leszek

    2010-03-01

    This work is devoted to the exact statistical mechanics treatment of simple inhomogeneous few-body systems. The system of two hard spheres (HSs) confined in a hard spherical pore is systematically analyzed in terms of its dimensionality D. The canonical partition function and the one- and two-body distribution functions are analytically evaluated and a scheme of iterative construction of the D +1 system properties is presented. We analyze in detail both the effect of high confinement, when particles become caged, and the low density limit. Other confinement situations are also studied analytically and several relations between the two HSs in a spherical pore, two sticked HSs in a spherical pore, and two HSs on a spherical surface partition functions are traced. These relations make meaningful the limiting caging and low density behavior. Turning to the system of two HSs in a spherical pore, we also analytically evaluate the pressure tensor. The thermodynamic properties of the system are discussed. To accomplish this statement we purposely focus in the overall characteristics of the inhomogeneous fluid system, instead of concentrate in the peculiarities of a few-body system. Hence, we analyze the equation of state, the pressure at the wall, and the fluid-substrate surface tension. The consequences of new results about the spherically confined system of two HSs in D dimension on the confined many HS system are investigated. New constant coefficients involved in the low density limit properties of the open and closed systems of many HS in a spherical pore are obtained for arbitrary D. The complementary system of many HS which surrounds a HS (a cavity inside of a bulk HS system) is also discussed.

  3. Thermospheric and geomagnetic responses to interplanetary coronal mass ejections observed by ACE and GRACE: Statistical results

    NASA Astrophysics Data System (ADS)

    Krauss, S.; Temmer, M.; Veronig, A.; Baur, O.; Lammer, H.

    2015-10-01

    For the period July 2003 to August 2010, the interplanetary coronal mass ejection (ICME) catalogue maintained by Richardson and Cane lists 106 Earth-directed events, which have been measured in situ by plasma and field instruments on board the ACE satellite. We present a statistical investigation of the Earth's thermospheric neutral density response by means of accelerometer measurements collected by the Gravity Recovery And Climate Experiment (GRACE) satellites, which are available for 104 ICMEs in the data set, and its relation to various geomagnetic indices and characteristic ICME parameters such as the impact speed (vmax), southward magnetic field strength (Bz). The majority of ICMEs causes a distinct density enhancement in the thermosphere, with up to a factor of 8 compared to the preevent level. We find high correlations between ICME Bz and thermospheric density enhancements (≈0.9), while the correlation with the ICME impact speed is somewhat smaller (≈0.7). The geomagnetic indices revealing the highest correlations are Dst and SYM-H(≈0.9); the lowest correlations are obtained for Kp and AE (≈0.7), which show a nonlinear relation with the thermospheric density enhancements. Separating the response for the shock-sheath region and the magnetic structure of the ICME, we find that the Dst and SYM-H reveal a tighter relation to the Bz minimum in the magnetic structure of the ICME, whereas the polar cap indices show higher correlations with the Bz minimum in the shock-sheath region. Since the strength of the Bz component—either in the sheath or in the magnetic structure of the ICME—is highly correlated (≈0.9) with the neutral density enhancement, we discuss the possibility of satellite orbital decay estimates based on magnetic field measurements at L1, i.e., before the ICME hits the Earth magnetosphere. These results are expected to further stimulate progress in space weather understanding and applications regarding satellite operations.

  4. Dosing free nitrous acid for sulfide control in sewers: results of field trials in Australia.

    PubMed

    Jiang, Guangming; Keating, Anthony; Corrie, Shaun; O'halloran, Kelly; Nguyen, Lam; Yuan, Zhiguo

    2013-09-01

    Intermittent dosing of free nitrous acid (FNA), with or without the simultaneous dosing of hydrogen peroxide, is a new strategy developed recently for the control of sulfide production in sewers. Six-month field trials have been carried out in a rising main sewer in Australia (150 mm in diameter and 1080 m in length) to evaluate the performance of the strategy that was previously demonstrated in laboratory studies. In each trial, FNA was dosed at a pumping station for a period of 8 or 24 h, some with simultaneous hydrogen peroxide dosing. The sulfide control effectiveness was monitored by measuring, on-line, the dissolved sulfide concentration at a downstream location of the pipeline (828 m from the pumping station) and the gaseous H2S concentration at the discharge manhole. Effective sulfide control was achieved in all nine consecutive trials, with sulfide production reduced by more than 80% in 10 days following each dose. Later trials achieved better control efficiency than the first few trials possibly due to the disrupting effects of FNA on sewer biofilms. This suggests that an initial strong dose (more chemical consumption) followed by maintenance dosing (less chemical consumption) could be a very cost-effective way to achieve consistent control efficiency. It was also found that heavy rainfall slowed the recovery of sulfide production after dosing, likely due to the dilution effects and reduced retention time. Overall, intermittent dose of FNA or FNA in combination with H2O2 was successfully demonstrated to be a cost-effective method for sulfide control in rising main sewers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Flipped Statistics Class Results: Better Performance than Lecture over One Year Later

    ERIC Educational Resources Information Center

    Winquist, Jennifer R.; Carlson, Keith A.

    2014-01-01

    In this paper, we compare an introductory statistics course taught using a flipped classroom approach to the same course taught using a traditional lecture based approach. In the lecture course, students listened to lecture, took notes, and completed homework assignments. In the flipped course, students read relatively simple chapters and answered…

  6. Preliminary results from a method to update timber resource statistics in North Carolina

    Treesearch

    Glenn P. Catts; Noel D. Cost; Raymond L. Czaplewski; Paul W. Snook

    1987-01-01

    Forest Inventory and Analysis units of the USDA Forest Service produce timber resource statistics every 8 to 10 years. Midcycle surveys are often performed to update inventory estimates. This requires timely identification of forest lands. There are several kinds of remotely sensed data that are suitable for this purpose. Medium scale color infrared aerial photography...

  7. Mainstreaming Remedial Mathematics Students in Introductory Statistics: Results Using a Randomized Controlled Trial

    ERIC Educational Resources Information Center

    Logue, Alexandra W.; Watanabe-Rose, Mari

    2014-01-01

    This study used a randomized controlled trial to determine whether students, assessed by their community colleges as needing an elementary algebra (remedial) mathematics course, could instead succeed at least as well in a college-level, credit-bearing introductory statistics course with extra support (a weekly workshop). Researchers randomly…

  8. Compendium of Single-Event Latchup and Total Ionizing Dose Test Results of Commercial Analog to Digital Converters

    NASA Technical Reports Server (NTRS)

    Irom, Farokh; Agarwal, Shri G.

    2012-01-01

    This paper reports single-event latchup and total dose results for a variety of analog to digital converters targeted for possible use in NASA spacecraft's. The compendium covers devices tested over the last 15 years.

  9. Compendium of Single-Event Latchup and Total Ionizing Dose Test Results of Commercial Analog to Digital Converters

    NASA Technical Reports Server (NTRS)

    Irom, Farokh; Agarwal, Shri G.

    2012-01-01

    This paper reports single-event latchup and total dose results for a variety of analog to digital converters targeted for possible use in NASA spacecraft's. The compendium covers devices tested over the last 15 years.

  10. Compendium of Current Total Ionizing Dose and Displacement Damage Results from NASA GSFC and NEPP

    NASA Technical Reports Server (NTRS)

    Topper, Alyson D.; Campola, Michael J.; Chen, Dakai; Casey, Megan C.; Yau, Ka-Yen; Label, Kenneth A.; Cochran, Donna J.; O'Bryan, Martha V.

    2017-01-01

    Total ionizing dose and displacement damage testing was performed to characterize and determine the suitability of candidate electronics for NASA space utilization. Devices tested include opto-electronics, digital, analog, linear bipolar devices, and hybrid devices.

  11. Offsite radiation doses from Hanford Operations for the years 1983 through 1987: A comparison of results calculated by two methods

    SciTech Connect

    Soldat, J.K.

    1989-10-01

    This report compares the results of the calculation of potential radiation doses to the public by two different environmental dosimetric systems for the years 1983 through 1987. Both systems project the environmental movement of radionuclides released with effluents from Hanford operations; their concentrations in air, water, and foods; the intake of radionuclides by ingestion and inhalation; and, finally, the potential radiation doses from radionuclides deposited in the body and from external sources. The first system, in use for the past decade at Hanford, calculates radiation doses in terms of 50-year cumulative dose equivalents to body organs and to the whole body, based on the methodology defined in ICRP Publication 2. This system uses a suite of three computer codes: PABLM, DACRIN, and KRONIC. In the new system, 50-year committed doses are calculated in accordance with the recommendations of the ICRP Publications 26 and 30, which were adopted by the US Department of Energy (DOE) in 1985. This new system calculates dose equivalent (DE) to individual organs and effective dose equivalent (EDE). The EDE is a risk-weighted DE that is designed to be an indicator of the potential health effects arising from the radiation dose. 16 refs., 1 fig., 38 tabs.

  12. Up-dosing with bilastine results in improved effectiveness in cold contact urticaria.

    PubMed

    Krause, K; Spohr, A; Zuberbier, T; Church, M K; Maurer, M

    2013-07-01

    Cold contact urticaria (CCU) is characterized by itchy wheal and flare responses due to the release of histamine and other pro-inflammatory mediators after exposure to cold. The treatment of choice is nonsedating antihistamines, dosages of which may be increased up to fourfold if standard doses are ineffective. Here, we assess the effects of a standard 20 mg dose and up-dosing to 40 and 80 mg of bilastine in reducing the symptoms of CCU and inflammatory mediator release following cold challenge. Twenty patients with CCU were included in this randomized, crossover, double-blind, placebo-controlled 12-week study. They received placebo, 20, 40 or 80 mg of bilastine daily each for 7 days with 14-day washout periods. The primary readout was change in critical temperature thresholds (CTT). Secondary readouts were changes in pruritus, levels of histamine IL-6, IL-8 and TNF-α collected by skin microdialysis and safety and tolerability of bilastine. Bilastine 20 mg was highly effective (P < 0.0001) in reducing CTT. Up-dosing to 80 mg significantly (P < 0.04) increased its effectiveness. At this dose, 19 of 20 (95%) patients responded to treatment, with 12 of 20 (60%) becoming symptom free. Only one patient was refractory to treatment. Microdialysis levels of histamine, IL-6 and IL-8 assessed 1-3 h after cold challenge were significantly (P < 0.05) decreased following up-dosing with 80 mg bilastine. Bilastine treatment was well tolerated without evidence of increased sedation with dose escalation. Bilastine was effective in reducing the symptoms of patients with CCU. Increased efficacy of bilastine with fourfold up-dosing was without sedation and supports urticaria treatment guidelines. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Acute low-dose endotoxin treatment results in improved whole-body glucose homeostasis in mice.

    PubMed

    Stevens, Joseph R; McMillan, Ryan P; Resendes, Justin T; Lloyd, Shannon K; Ali, Mostafa M; Frisard, Madlyn I; Hargett, Stefan; Keller, Susanna R; Hulver, Matthew W

    2017-03-01

    Obese individuals present with an increased inflammatory tone as compared to healthy, normal-weight individuals, which is associated with insulin resistance. One factor hypothesized to contribute to increased inflammation in obese and diabetic states is elevated blood endotoxin levels, a condition known as metabolic endotoxemia. In non-obese and insulin sensitive individuals, circulating endotoxin concentrations fluctuate over the course of the day with elevations in the post-prandial state that return to baseline levels in the post-absorptive state. Evidence suggests that high-fat feeding alters these fluctuations causing endotoxin levels to remain high throughout the day. The effects of alterations in endotoxin levels on glucose metabolism are not clearly understood. The goal of this study was to determine the effects of both short-term and long-term increases in endotoxin (lipopolysaccharide, LPS) of a low magnitude on the glucose tolerance and insulin signaling in a human primary cell line as well as the effects of short-term endotoxin treatments on glucose homeostasis in a C57/Bl6 mouse model. First, we tested the hypothesis that short-term low-dose endotoxin treatments would augment insulin signaling and glycogen synthesis while long-term treatments would be disruptive in the cell culture model. Second, we examined if these short-term low dose treatments of endotoxin would contribute to similar improvements in whole-body glucose homeostasis in a mouse model. Contrary to our initial hypothesis, short-term endotoxin treatment had no effect on insulin signaling or glycogen synthesis, however long-term treatment indeed decreased glycogen synthesis (P<.05). Interestingly, short-term endotoxin treatment resulted in significant improvements in glucose homeostasis in the mouse model (P<.01); which is believed to be at least partly attributed to an inhibitory action of LPS on liver glucose production. This research shows that low-magnitude, short-term changes in LPS

  14. High dose intensity combination chemotherapy for advanced epithelial ovarian carcinoma: results of a pilot study.

    PubMed Central

    Sweetenham, J. W.; McKendrick, J. J.; Jones, D. H.; Whitehouse, J. M.; Williams, C. J.

    1990-01-01

    Retrospective studies have recently demonstrated a significant correlation between dose intensity of chemotherapy and response rates and survival in various diseases including epithelial ovarian carcinoma. As part of a proposed randomised trial to assess the effect of dose intensity on outcome in ovarian carcinoma, a pilot study has been undertaken to determine the toxicity and efficacy of the high intensity therapy. Nineteen patients with advanced ovarian carcinoma received initial treatment with cisplatin 120 mg m-2 i.v. day 1, and cyclophosphamide 1,000 mg-2 i.v. day 1, given at 21-day intervals for six cycles. The average relative dose intensity of this therapy is 1.14 when compared with the CHAP regimen. Severe toxicity was experienced by most patients. The median received average relative dose intensity was 0.90, with only one patient receiving treatment to the proposed intensity. Randomised studies of the effect of dose intensity in ovarian carcinoma are essential, but an initial step must be to assess whether the proposed high dose treatment can be delivered. PMID:2155645

  15. Initial communication survey results for the Hanford Environmental Dose Reconstruction Project

    SciTech Connect

    Beck, D.M.

    1991-03-01

    To support the public communication efforts of the Technical Steering Panel of the Hanford Environmental Dose Reconstruction (HEDR) Project, a public survey was conducted. The survey was intended to provide information about the public's knowledge and interest in the project and the best ways to communicate project results. Questions about the project were included as part of an omnibus survey conducted by Washington State University. The survey was conducted by phone to Washington State residents in the spring of 1990. This report gives the HEDR-related questions and summary data of responses. Questions associated with the HEDR Project were grouped into four categories: knowledge of the HEDR Project; interest in the project; preferred ways of receiving information about the project (including public information meetings, a newsletter mailed to homes, presentations to civic groups in the respondent's community, a computer bulletin board respondent could access with a modem, information displays at public buildings and shopping malls, and an information video sent to respondent); and level of concern over past exposure from Hanford operations. Questions abut whom state residents are most likely to trust about radiation issues were also part of the omnibus survey, and responses are included in this report.

  16. RESULTS OF RELID STUDY 2014-BUENOS AIRES, ARGENTINA RETROSPECTIVE EVALUATION OF LENS INJURIES AND DOSE.

    PubMed

    Papp, C; Romano-Miller, M; Descalzo, A; Michelin, S; Molinari, A; Rossini, A; Plotkin, C; Bodino, G; Esperanza, G; Di Giorgio, M; Touzet, R

    2017-04-01

    High levels of scatter radiation in catheterization laboratories may lead to posterior subcapsular opacities in the lens of the staff. The international Retrospective Evaluation of Lens Injuries and Dose (RELID) was performed in Argentina for the first time in 2010 in the context of the congress of the Latin American Society of Interventional Cardiology (SOLACI) and recently, in 2014, was carried out for the second time (SOLACI-CACI 2014). The 2014 study included 115 participants: interventional cardiologists, technicians and nurses. Posterior subcapsular lens changes typical of ionizing radiation exposure were found in 91.5% of interventional cardiologists, in 77% of technicians and in 100% of nurses, according to the Merriam-Focht scale. This RELID study (Argentina 2014) has particular importance since it allowed the follow-up of 10 professionals evaluated in 2010. The results obtained in the study population highlight the importance of the availability and proper use of the elements of radiation protection, as well as staff training. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Is the applicability of fractal statistics to sedimentary structures the result of scale-invariant stochastic processes or deterministic chaos

    SciTech Connect

    Turcotte, D.L. )

    1991-03-01

    Fractal statistics are the only statistics that are scale invariant. Examples in tectonics include distributions of faults, displacements on faults, distributions and permeabilities of fractures, and distributions of folds. Many aspects of sedimentology are also fractal including distributions of sedimentary sequences, variations in permeability, and shapes of boundaries. Since the underlying processes are likely to be scale invariant, it is reasonable to conclude that the number-size statistics of oil fields will be fractal. Log-normal statistics are often applied; they are not scale invariant. Two explanations for fractal statistics can be given. They may be the result of scale-invariant stochastic processes. Random walk (Brownian noise) is one example. Topography generally resembles Brownian noise, a power-law spectrum with fractal dimension D = 1.5. Alternatively fractal statistics can be the result of deterministic chaos. Turbulent flows are examples of deterministic chaos, the governing equations are deterministic but the resulting flows are statistical. Tectonic displacements can be shown to be the result of deterministic chaos; it is likely that erosion is another example.

  18. A Multivariate Statistical Analysis of Spiral Galaxy Luminosities. I. Data and Results

    NASA Astrophysics Data System (ADS)

    Shapley, Alice; Fabbiano, G.; Eskridge, P. B.

    2001-11-01

    grains by the same UV photon field. Other highly significant ``fundamental'' correlations exist but are morphology dependent. In particular, in the late sample (Sc-Irr) we see an overall connection of mid-IR, far-IR, and radio continuum emission, which could be related to the presence of star-forming activity in these galaxies, while in early-type spirals (S0/a-Sab), we find no strong direct link of FIR and radio continuum. This paper gives a compilation of both input data and results of our systematic statistical analysis, as well as a discussion of potential biases. Results relevant to both X-ray and multiwavelength emission properties are analyzed further and discussed in Paper II.

  19. US Geological Survey nutrient preservation experiment : experimental design, statistical analysis, and interpretation of analytical results

    USGS Publications Warehouse

    Patton, Charles J.; Gilroy, Edward J.

    1999-01-01

    Data on which this report is based, including nutrient concentrations in synthetic reference samples determined concurrently with those in real samples, are extensive (greater than 20,000 determinations) and have been published separately. In addition to confirming the well-documented instability of nitrite in acidified samples, this study also demonstrates that when biota are removed from samples at collection sites by 0.45-micrometer membrane filtration, subsequent preservation with sulfuric acid or mercury (II) provides no statistically significant improvement in nutrient concentration stability during storage at 4 degrees Celsius for 30 days. Biocide preservation had no statistically significant effect on the 30-day stability of phosphorus concentrations in whole-water splits from any of the 15 stations, but did stabilize Kjeldahl nitrogen concentrations in whole-water splits from three data-collection stations where ammonium accounted for at least half of the measured Kjeldahl nitrogen.

  20. Effect of experimental parameters and resulting analytical signal statistics in laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Klus, Jakub; Pořízka, Pavel; Prochazka, David; Novotný, Jan; Novotný, Karel; Kaiser, Jozef

    2016-12-01

    The purpose of this work is to provide detailed study of statistical behavior of different types of analytical signals in typical of Laser-Induced Breakdown Spectroscopy (LIBS) measurements. The main goal of this work is to justify usage of arithmetic mean and standard deviation as statistical estimates of expected value of selected analytical signal. In contrary to the general assumption that LIBS data show Gaussian distribution, this paper deals with the hypothesis that the data rather demonstrate Generalized Extreme Value Distribution. The study is realized on 10 selected lines measured on NIST glass standard. In order to cover wide range of possible applications three different spectra internal standardization techniques and their influence on distribution were studied. Finally, assuming that the data comes from a single distribution and the central limit theorem is valid, the influence of accumulations on the line distribution is examined and discussed. Statistical tools used and described in this paper can be utilized by other researchers to confirm their hypotheses and verify utilization of Gaussian distribution or even novel data processing methods.

  1. Multileaf Collimator Tracking Improves Dose Delivery for Prostate Cancer Radiation Therapy: Results of the First Clinical Trial

    SciTech Connect

    Colvill, Emma; Booth, Jeremy T.; O'Brien, Ricky T.; Eade, Thomas N.; Kneebone, Andrew B.; Poulsen, Per R.; Keall, Paul J.

    2015-08-01

    Purpose: To test the hypothesis that multileaf collimator (MLC) tracking improves the consistency between the planned and delivered dose compared with the dose without MLC tracking, in the setting of a prostate cancer volumetric modulated arc therapy trial. Methods and Materials: Multileaf collimator tracking was implemented for 15 patients in a prostate cancer radiation therapy trial; in total, 513 treatment fractions were delivered. During each treatment fraction, the prostate trajectory and treatment MLC positions were collected. These data were used as input for dose reconstruction (multiple isocenter shift method) to calculate the treated dose (with MLC tracking) and the dose that would have been delivered had MLC tracking not been applied (without MLC tracking). The percentage difference from planned for target and normal tissue dose-volume points were calculated. The hypothesis was tested for each dose-volume value via analysis of variance using the F test. Results: Of the 513 fractions delivered, 475 (93%) were suitable for analysis. The mean difference and standard deviation between the planned and treated MLC tracking doses and the planned and without-MLC tracking doses for all 475 fractions were, respectively, PTV D{sub 99%} −0.8% ± 1.1% versus −2.1% ± 2.7%; CTV D{sub 99%} −0.6% ± 0.8% versus −0.6% ± 1.1%; rectum V{sub 65%} 1.6% ± 7.9% versus −1.2% ± 18%; and bladder V{sub 65%} 0.5% ± 4.4% versus −0.0% ± 9.2% (P<.001 for all dose-volume results). Conclusion: This study shows that MLC tracking improves the consistency between the planned and delivered doses compared with the modeled doses without MLC tracking. The implications of this finding are potentially improved patient outcomes, as well as more reliable dose-volume data for radiobiological parameter determination.

  2. The Impact of Acquisition Dose on Quantitative Breast Density Estimation with Digital Mammography: Results from ACRIN PA 4006

    PubMed Central

    Chen, Lin; Ray, Shonket; Keller, Brad M.; Pertuz, Said; McDonald, Elizabeth S.; Conant, Emily F.

    2016-01-01

    Purpose To investigate the impact of radiation dose on breast density estimation in digital mammography. Materials and Methods With institutional review board approval and Health Insurance Portability and Accountability Act compliance under waiver of consent, a cohort of women from the American College of Radiology Imaging Network Pennsylvania 4006 trial was retrospectively analyzed. All patients underwent breast screening with a combination of dose protocols, including standard full-field digital mammography, low-dose digital mammography, and digital breast tomosynthesis. A total of 5832 images from 486 women were analyzed with previously validated, fully automated software for quantitative estimation of density. Clinical Breast Imaging Reporting and Data System (BI-RADS) density assessment results were also available from the trial reports. The influence of image acquisition radiation dose on quantitative breast density estimation was investigated with analysis of variance and linear regression. Pairwise comparisons of density estimations at different dose levels were performed with Student t test. Agreement of estimation was evaluated with quartile-weighted Cohen kappa values and Bland-Altman limits of agreement. Results Radiation dose of image acquisition did not significantly affect quantitative density measurements (analysis of variance, P = .37 to P = .75), with percent density demonstrating a high overall correlation between protocols (r = 0.88–0.95; weighted κ = 0.83–0.90). However, differences in breast percent density (1.04% and 3.84%, P < .05) were observed within high BI-RADS density categories, although they were significantly correlated across the different acquisition dose levels (r = 0.76–0.92, P < .05). Conclusion Precision and reproducibility of automated breast density measurements with digital mammography are not substantially affected by variations in radiation dose; thus, the use of low-dose techniques for the purpose of density

  3. The Impact of Acquisition Dose on Quantitative Breast Density Estimation with Digital Mammography: Results from ACRIN PA 4006.

    PubMed

    Chen, Lin; Ray, Shonket; Keller, Brad M; Pertuz, Said; McDonald, Elizabeth S; Conant, Emily F; Kontos, Despina

    2016-09-01

    Purpose To investigate the impact of radiation dose on breast density estimation in digital mammography. Materials and Methods With institutional review board approval and Health Insurance Portability and Accountability Act compliance under waiver of consent, a cohort of women from the American College of Radiology Imaging Network Pennsylvania 4006 trial was retrospectively analyzed. All patients underwent breast screening with a combination of dose protocols, including standard full-field digital mammography, low-dose digital mammography, and digital breast tomosynthesis. A total of 5832 images from 486 women were analyzed with previously validated, fully automated software for quantitative estimation of density. Clinical Breast Imaging Reporting and Data System (BI-RADS) density assessment results were also available from the trial reports. The influence of image acquisition radiation dose on quantitative breast density estimation was investigated with analysis of variance and linear regression. Pairwise comparisons of density estimations at different dose levels were performed with Student t test. Agreement of estimation was evaluated with quartile-weighted Cohen kappa values and Bland-Altman limits of agreement. Results Radiation dose of image acquisition did not significantly affect quantitative density measurements (analysis of variance, P = .37 to P = .75), with percent density demonstrating a high overall correlation between protocols (r = 0.88-0.95; weighted κ = 0.83-0.90). However, differences in breast percent density (1.04% and 3.84%, P < .05) were observed within high BI-RADS density categories, although they were significantly correlated across the different acquisition dose levels (r = 0.76-0.92, P < .05). Conclusion Precision and reproducibility of automated breast density measurements with digital mammography are not substantially affected by variations in radiation dose; thus, the use of low-dose techniques for the purpose of density estimation

  4. Increasing the dose of television advertising in a national antismoking media campaign: results from a randomised field trial.

    PubMed

    McAfee, Tim; Davis, Kevin C; Shafer, Paul; Patel, Deesha; Alexander, Robert; Bunnell, Rebecca

    2017-01-01

    While antismoking media campaigns have demonstrated effectiveness, less is known about the country-level effects of increased media dosing. The 2012 US Tips From Former Smokers (Tips) campaign generated approximately 1.6 million quit attempts overall; however, the specific dose-response from the campaign was only assessed by self-report. Assess the impact of higher ad exposure during the 2013 Tips campaign on quit-related behaviours and intentions, campaign awareness, communication about campaign, and disease knowledge. A 3-month national media buy was supplemented within 67 (of 190) randomly selected local media markets. Higher-dose markets received media buys 3 times that of standard-dose markets. We compared outcomes of interest using data collected via web-based surveys from nationally representative, address-based probability samples of 5733 cigarette smokers and 2843 non-smokers. In higher-dose markets, 87.2% of smokers and 83.9% of non-smokers recalled television campaign exposure versus 75.0% of smokers and 73.9% of non-smokers in standard-dose markets. Among smokers overall, the relative quit attempt rate was 11% higher in higher-dose markets (38.8% vs 34.9%; p<0.04). The higher-dose increase was larger in African-Americans (50.9% vs 31.8%; p<0.01). Smokers in higher-dose markets without a mental health condition, with a chronic health condition, or with only some college education made quit attempts at a higher rate than those in standard-dose markets. Non-smokers in higher-dose markets were more likely to talk with family or friends about smoking dangers (43.1% vs 35.7%; p<0.01) and had greater knowledge of smoking-related diseases. The US 2013 Tips antismoking media campaign compared standard and higher doses by randomisation of local media markets. Results demonstrate the effectiveness of a higher dose for engaging non-smokers and further increasing quit attempts among smokers, especially African-Americans. Published by the BMJ Publishing Group Limited

  5. Relation Between Dose of Loop Diuretics and Outcomes in a Heart Failure Population: Results of the ESCAPE Trial

    PubMed Central

    Hasselblad, Vic; Stough, Wendy Gattis; Shah, Monica R.; Lokhnygina, Yuliya; O’Connor, Christopher M.; Califf, Robert M.; Adams, Kirkwood F.

    2007-01-01

    Background We examined the relation of maximal in-hospital diuretic dose to weight loss, changes in renal function, and mortality in hospitalised heart failure (HF) patients. Methods In ESCAPE, 395 patients received diuretics in-hospital. Weight was measured at baseline, discharge, and every other day before discharge. Weight loss was defined as the difference between baseline and last in-hospital weight. Mortality was assessed using a log-logistic model with non-zero background. Results Median weight loss: 2.8 kg (0.7, 6.1); mean: 3.7 kg (22% of values <0). Weight loss and maximum in-hospital dose were correlated (p = 0.0007). Baseline weight, length of stay, and baseline brain natriuretic peptide were significant predictors of weight loss. After adjusting for these, dose was not a significant predictor of weight loss. A strong relation between dose and mortality was seen (p = 0.003), especially at >300 mg/day. Dose remained a significant predictor of mortality after adjusting for baseline variables that significantly predicted mortality. Correlation between maximal dose and creatinine level change was not significant (r = 0.043; p = 0.412) Conclusions High diuretic doses during HF hospitalisation are associated with increased mortality and poor 6-month outcome. PMID:17719273

  6. Low-Dose Computed Tomography With Adaptive Statistical Iterative Reconstruction and Low Tube Voltage in Craniocervical Computed Tomographic Angiography: Impact of Body Mass Index.

    PubMed

    You, Jia; Dai, Yue; Huang, Ning; Li, Jing-Jing; Cheng, Li; Zhang, Xiu-Li; Liu, Qi; Liu, Ying; Xu, Kai

    2015-01-01

    To assess radiation dose and image quality using Adaptive Statistical Iterative Reconstruction (ASIR) in craniocervical computed tomographic angiography and to further evaluate the impact of body mass index (BMI) on image quality. A total of 178 consecutive patients (112 men, 66 women; age range, 25-79 years) were enrolled in this prospective study and randomly divided into 2 groups: group A (conventional group): 120 kV, filtered back-projection reconstruction, and group B (low-dose group): 100 kV, 40% ASIR reconstruction. Radiation dose and image quality between groups A and B were compared. Correlation coefficients were calculated between quantitative image quality measurement and BMI, and between radiation dose and BMI using Pearson correlation. Two experienced radiologists independently evaluated the image quality with 4-point scores, and interrater reliability was calculated using κ analysis. The volume CT dose index, dose-length product, and effective dose of group B were lower than those of group A (each P < 0.01), with decreases of 23.99%, 25.15% and 25.47% respectively. Positive correlations existed between radiation dose and BMI for both groups A and B (each P < 0.01). Group B had lower image noise, higher attenuation, higher signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), and higher subjective score than did group A (each P < 0.01). Computed tomographic values had negative correlations with BMI for the head, neck, and shoulders in both groups A and B (each P < 0.01). Image noise, SNR, and CNR had no correlations with BMI for the head and neck in both groups (each P > 0.01). On the contrary, image noise had a positive correlation, and SNR and CNR had a negative correlations with BMI for the shoulders in group A (each P < 0.01), but in contrast, no such correlations were found in group B (each P > 0.01). In craniocervical CTA, ASIR can improve the image quality and reduce radiation dose in patients. Furthermore, ASIR reduced the variances

  7. New results in omega photoproduction using high-statistics data obtained from CLAS at Jefferson Lab

    SciTech Connect

    Williams, Michael

    2009-01-01

    High-statistics differential cross sections and spin density matrix elements for the reaction {gamma}p --> p{omega} have been measured using the CLAS at Jefferson Lab for center-of-mass energies, W, from threshold up to 2.84 GeV. An event-based partial wave analysis (PWA) has also been performed on the data. This analysis benefits from access to the world's first high precision spin density matrix element measurements, available to the event-based PWA through the decay distribution of omega-->pi+pi-pi0. Strong evidence has been found for nucleon resonance contributions.

  8. Unmatched masses in peptide mass fingerprints caused by cross-contamination: an updated statistical result.

    PubMed

    Ding, Qinxue; Xiao, Lin; Xiong, Shaoxiang; Jia, Yufeng; Que, Haiping; Guo, Yaojun; Liu, Shaojun

    2003-07-01

    Unmatched masses are often observed in the experimental peptide mass spectra when database searching is performed with the ProFound program. Comparison between theoretical and experimental mass spectra of standard proteins shows that contamination accounts for most of the unmatched masses. In this retrospective analysis, the top 100 most probable contaminating masses, as listed in order of their probability, are statistically filtered out from 118 different experimental peptide mass fingerprinting (PMF) maps. Most of the interfering masses originate from trypsin autolysis and human keratins. Subtraction of known contaminants from raw data and using cleaner masses for searching can enhance protein identification by PMF.

  9. The breaking load method - Results and statistical modification from the ASTM interlaboratory test program

    NASA Technical Reports Server (NTRS)

    Colvin, E. L.; Emptage, M. R.

    1992-01-01

    The breaking load test provides quantitative stress corrosion cracking data by determining the residual strength of tension specimens that have been exposed to corrosive environments. Eight laboratories have participated in a cooperative test program under the auspices of ASTM Committee G-1 to evaluate the new test method. All eight laboratories were able to distinguish between three tempers of aluminum alloy 7075. The statistical analysis procedures that were used in the test program do not work well in all situations. An alternative procedure using Box-Cox transformations shows a great deal of promise. An ASTM standard method has been drafted which incorporates the Box-Cox procedure.

  10. The breaking load method - Results and statistical modification from the ASTM interlaboratory test program

    NASA Technical Reports Server (NTRS)

    Colvin, E. L.; Emptage, M. R.

    1992-01-01

    The breaking load test provides quantitative stress corrosion cracking data by determining the residual strength of tension specimens that have been exposed to corrosive environments. Eight laboratories have participated in a cooperative test program under the auspices of ASTM Committee G-1 to evaluate the new test method. All eight laboratories were able to distinguish between three tempers of aluminum alloy 7075. The statistical analysis procedures that were used in the test program do not work well in all situations. An alternative procedure using Box-Cox transformations shows a great deal of promise. An ASTM standard method has been drafted which incorporates the Box-Cox procedure.

  11. Pill content, dose and resulting plasma concentrations of 3,4-methylendioxymethamphetamine (MDMA) in recreational 'ecstasy' users.

    PubMed

    Morefield, Kate M; Keane, Michael; Felgate, Peter; White, Jason M; Irvine, Rodney J

    2011-07-01

    To improve our understanding of the pharmacology of 'ecstasy' in recreational environments; in particular, to describe the composition of ecstasy pills, patterns of ecstasy use and the relationship between dose of 3,4-methylendioxymethamphetamine (MDMA) and resulting plasma concentrations. A naturalistic observational study of 56 experienced 'ecstasy' users in recreational settings in Australia. Drug use patterns (number of pills consumed, other drugs consumed). drug content of pills and resultant plasma concentrations of MDMA and related drugs were assessed by gas chromatography/mass spectrometry (GC/MS). Ecstasy pills generally contained MDMA, but this was often combined with other drugs such as 3,4-ethylendioxyethylamphetamine (MDEA) and methamphetamine. The dose of MDMA per pill ranged from 0 to 245 mg and users consumed from one-half to five pills, with the total dose consumed ranging up to 280 mg. Plasma concentrations of MDMA increased with number of pills consumed and cumulative MDMA dose. Use of larger numbers of pills was associated with extended exposure to the drug. MDMA is the major active drug in ecstasy pills, but there is a high degree of variation in doses. Use of multiple pills over the course of one session is common and results in a sustained increase in MDMA plasma concentrations over a number of hours. This is likely to lead to a much greater exposure of the brain to MDMA than would be predicted from controlled single-dose pharmacokinetic studies. © 2011 The Authors, Addiction © 2011 Society for the Study of Addiction.

  12. Increasing the dose of television advertising in a national antismoking media campaign: results from a randomised field trial

    PubMed Central

    McAfee, Tim; Davis, Kevin C; Shafer, Paul; Patel, Deesha; Alexander, Robert; Bunnell, Rebecca

    2017-01-01

    Background While antismoking media campaigns have demonstrated effectiveness, less is known about the country-level effects of increased media dosing. The 2012 US Tips From Former Smokers (Tips) campaign generated approximately 1.6 million quit attempts overall; however, the specific dose–response from the campaign was only assessed by self-report. Objective Assess the impact of higher ad exposure during the 2013 Tips campaign on quit-related behaviours and intentions, campaign awareness, communication about campaign, and disease knowledge. Methods A 3-month national media buy was supplemented within 67 (of 190) randomly selected local media markets. Higher-dose markets received media buys 3 times that of standard-dose markets. We compared outcomes of interest using data collected via web-based surveys from nationally representative, address-based probability samples of 5733 cigarette smokers and 2843 non-smokers. Results In higher-dose markets, 87.2% of smokers and 83.9% of non-smokers recalled television campaign exposure versus 75.0% of smokers and 73.9% of non-smokers in standard-dose markets. Among smokers overall, the relative quit attempt rate was 11% higher in higher-dose markets (38.8% vs 34.9%; p<0.04). The higher-dose increase was larger in African-Americans (50.9% vs 31.8%; p<0.01). Smokers in higher-dose markets without a mental health condition, with a chronic health condition, or with only some college education made quit attempts at a higher rate than those in standard-dose markets. Non-smokers in higher-dose markets were more likely to talk with family or friends about smoking dangers (43.1% vs 35.7%; p<0.01) and had greater knowledge of smoking-related diseases. Conclusions The US 2013 Tips antismoking media campaign compared standard and higher doses by randomisation of local media markets. Results demonstrate the effectiveness of a higher dose for engaging non-smokers and further increasing quit attempts among smokers, especially African

  13. Statistical analysis of results of carcinogenicity studies of synthetic vitreous fibres at Research and Consulting Company, Geneva.

    PubMed

    Rossiter, C E; Chase, J R

    1995-10-01

    Five inhalation studies of synthetic vitreous fibres have recently investigated experimental tumorigenic responses to four different refractory ceramic fibres (RCF), two fibre glasses, one stone (rock) wool and one slag wool. Except for one RCF, the source materials were typical commercial products. Three studies included positive control groups exposed to chrysotile or crocidolite asbestos. The studies were conducted using state-of-the-art technologies for fibre size separation, fibre lofting and nose-only inhalation exposure. The target average fibre size was 20 microns long by 1 micron diameter. Hamsters exposed to a kaolin RCF yielded a mesothelioma rate of 38%, but no lung cancers. There were no tumours among the chrysotile-exposed hamsters. At the highest dose of 30 mg m-3 in rat studies, the commercial RCF all produced significant numbers of lung tumours, and some mesotheliomas. The fourth RCF, which had been heat-treated to simulate an after-service fibre, did not produce a significant excess of lung cancers, but did produce one mesothelioma. A rat multi-dose experiment with three lower doses of the kaolin RCF yielded one mesothelioma among 379 rats, but no excess of lung tumours. The overall dose-response relation for lung cancer did not appear to be linear, consistent with the possibility of a threshold close to the Maximum Tolerated Dose. No insulation wool (glass, stone or slag) exposure group had a lung tumour rate that differed statistically significantly from the tumour rate for the respective concurrent control groups, sham-exposed to filtered air. There was no significant difference in the total tumour rates between the four insulation wool groups and the control animals, and no significant dose-response relation above the respective sham-exposed control tumour rates. The total lung tumour rates for rats in both chrysotile and crocidolite exposure groups were significantly raised. One animal in each asbestos-exposed group developed a mesothelioma

  14. Statistical tools for analysing the data obtained from repeated dose toxicity studies with rodents: a comparison of the statistical tools used in Japan with that of used in other countries.

    PubMed

    Kobayashi, Katsumi; Pillai, K Sadasivan; Guhatakurta, Soma; Cherian, K M; Ohnishi, Mariko

    2011-01-01

    In the present study, an attempt was made to compare the statistical tools used for analysing the data of repeated dose toxicity studies with rodents conducted in 45 countries, with that of Japan. The study revealed that there was no congruence among the countries in the use of statistical tools for analysing the data obtained from the above studies. For example, to analyse the data obtained from repeated dose toxicity studies with rodents, Scheffé's multiple range and Dunnett type (joint type Dunnett) tests are commonly used in Japan, but in other countries use of these statistical tools is not so common. However, statistical techniques used for testing the above data for homogeneity of variance and inter-group comparisons do not differ much between Japan and other countries. In Japan, the data are generally not tested for normality and the same is true with the most of the countries investigated. In the present investigation, out of 127 studies examined, data of only 6 studies were analysed for both homogeneity of variance and normal distribution. For examining homogeneity of variance, we propose Levene's test, since the commonly used Bartlett's test may show heterogeneity in variance in all the groups, if a slight heterogeneity in variance is seen any one of the groups. We suggest the data may be examined for both homogeneity of variance and normal distribution. For the data of the groups that do not show heterogeneity of variance, to find the significant difference among the groups, we recommend Dunnett's test, and for those show heterogeneity of variance, we recommend Steel's test.

  15. Results of the Phase I Dose-Escalating Study of Motexafin Gadolinium With Standard Radiotherapy in Patients With Glioblastoma Multiforme

    SciTech Connect

    Ford, Judith M. Seiferheld, Wendy; Alger, Jeffrey R.; Wu, Genevieve; Endicott, Thyra J.; Mehta, Minesh; Curran, Walter; Phan, See-Chun

    2007-11-01

    Purpose: Motexafin gadolinium (MGd) is a putative radiation enhancer initially evaluated in patients with brain metastases. This Phase I trial studied the safety and tolerability of a 2-6-week course (10-22 doses) of MGd with radiotherapy for glioblastoma multiforme. Methods and Materials: A total of 33 glioblastoma multiforme patients received one of seven MGd regimens starting at 10 doses of 4 mg/kg/d MGd and escalating to 22 doses of 5.3 mg/kg/d MGd (5 or 10 daily doses then three times per week). The National Cancer Institute Cancer Therapy Evaluation Program toxicity and stopping rules were applied. Results: The maximal tolerated dose was 5.0 mg/kg/d MGd (5 d/wk for 2 weeks, then three times per week) for 22 doses. The dose-limiting toxicity was reversible transaminase elevation. Adverse reactions included rash/pruritus (45%), chills/fever (30%), and self-limiting vesiculobullous rash of the thumb and fingers (42%). The median survival of 17.6 months prompted a case-matched analysis. In the case-matched analysis, the MGd patients had a median survival of 16.1 months (n = 31) compared with the matched Radiation Therapy Oncology Group database patients with a median survival of 11.8 months (hazard ratio, 0.43; 95% confidence interval, 0.20-0.94). Conclusion: The maximal tolerated dose of MGd with radiotherapy for glioblastoma multiforme in this study was 5 mg/kg/d for 22 doses (daily for 2 weeks, then three times weekly). The baseline survival calculations suggest progression to Phase II trials is appropriate, with the addition of MGd to radiotherapy with concurrent and adjuvant temozolomide.

  16. Supercomputing enabling exhaustive statistical analysis of genome wide association study data: Preliminary results.

    PubMed

    Reumann, Matthias; Makalic, Enes; Goudey, Benjamin W; Inouye, Michael; Bickerstaffe, Adrian; Bui, Minh; Park, Daniel J; Kapuscinski, Miroslaw K; Schmidt, Daniel F; Zhou, Zeyu; Qian, Guoqi; Zobel, Justin; Wagner, John; Hopper, John L

    2012-01-01

    Most published GWAS do not examine SNP interactions due to the high computational complexity of computing p-values for the interaction terms. Our aim is to utilize supercomputing resources to apply complex statistical techniques to the world's accumulating GWAS, epidemiology, survival and pathology data to uncover more information about genetic and environmental risk, biology and aetiology. We performed the Bayesian Posterior Probability test on a pseudo data set with 500,000 single nucleotide polymorphism and 100 samples as proof of principle. We carried out strong scaling simulations on 2 to 4,096 processing cores with factor 2 increments in partition size. On two processing cores, the run time is 317h, i.e. almost two weeks, compared to less than 10 minutes on 4,096 processing cores. The speedup factor is 2,020 that is very close to the theoretical value of 2,048. This work demonstrates the feasibility of performing exhaustive higher order analysis of GWAS studies using independence testing for contingency tables. We are now in a position to employ supercomputers with hundreds of thousands of threads for higher order analysis of GWAS data using complex statistics.

  17. Ophthalmological results from a placebo controlled comparative 3-dose ivermectin study in the treatment of onchocerciasis.

    PubMed

    Dadzie, K Y; Awadzi, K; Bird, A C; Schulz-Key, H

    1989-09-01

    One hundred and ninety eight patients with moderate to heavy infection with Onchocerca volvulus and with eye involvement in most, were allocated randomly to treatment with 100, 150 or 200 mcg/kg body weight of ivermectin or placebo given as a single oral dose in a double-blind dose finding study. The patients were drawn from an area under over ten years of vector control in Northern Ghana by the Onchocerciasis Control Programme, OCP. They underwent detailed clinical, laboratory and ophthalmological examination before treatment and in the review period of one year in hospital. Ivermectin given in a dose of 100, 150 or 200 mcg/kg eliminated microfilariae similarly slowly over 3-6 months and was associated with inflammatory reaction in the anterior segment which resolved without treatment. No changes in the fundus of the eye was detected by fluorescein angiography and no no-table other adverse eye reaction was observed. The ceiling of therapeutic activity of ivermectin in the eye is therefore put at 100 mcg/kg which is lower than the level fo 150 mcg/kg found in the skin. The apparent discrepancy may be due to different dose requirements on account of different mechanisms of action of ivermectin at the two sites. In the skin there is active killing while in the eye it is presumed there is a passive elimination of microfilariae.

  18. The cross-cut statistic and its sensitivity to bias in observational studies with ordered doses of treatment.

    PubMed

    Rosenbaum, Paul R

    2016-03-01

    A common practice with ordered doses of treatment and ordered responses, perhaps recorded in a contingency table with ordered rows and columns, is to cut or remove a cross from the table, leaving the outer corners--that is, the high-versus-low dose, high-versus-low response corners--and from these corners to compute a risk or odds ratio. This little remarked but common practice seems to be motivated by the oldest and most familiar method of sensitivity analysis in observational studies, proposed by Cornfield et al. (1959), which says that to explain a population risk ratio purely as bias from an unobserved binary covariate, the prevalence ratio of the covariate must exceed the risk ratio. Quite often, the largest risk ratio, hence the one least sensitive to bias by this standard, is derived from the corners of the ordered table with the central cross removed. Obviously, the corners use only a portion of the data, so a focus on the corners has consequences for the standard error as well as for bias, but sampling variability was not a consideration in this early and familiar form of sensitivity analysis, where point estimates replaced population parameters. Here, this cross-cut analysis is examined with the aid of design sensitivity and the power of a sensitivity analysis.

  19. Differences in Clinical Results After LINAC-Based Single-Dose Radiosurgery Versus Fractionated Stereotactic Radiotherapy for Patients With Vestibular Schwannomas

    SciTech Connect

    Combs, Stephanie E.; Welzel, Thomas; Schulz-Ertner, Daniela; Huber, Peter E.; Debus, Juergen

    2010-01-15

    Purpose: To evaluate the outcomes of patients with vestibular schwannoma (VS) treated with fractionated stereotactic radiotherapy (FSRT) vs. those treated with stereotactic radiosurgery (SRS). Methods and Materials: This study is based on an analysis of 200 patients with 202 VSs treated with FSRT (n = 172) or SRS (n = 30). Patients with tumor progression and/or progression of clinical symptoms were selected for treatment. In 165 out of 202 VSs (82%), RT was performed as the primary treatment for VS, and for 37 VSs (18%), RT was conducted for tumor progression after neurosurgical intervention. For patients receiving FSRT, a median total dose of 57.6 Gy was prescribed, with a median fractionation of 5 x 1.8 Gy per week. For patients who underwent SRS, a median single dose of 13 Gy was prescribed to the 80% isodose. Results: FSRT and SRS were well tolerated. Median follow-up time was 75 months. Local control was not statistically different for both groups. The probability of maintaining the pretreatment hearing level after SRS with doses of <=13 Gy was comparable to that of FSRT. The radiation dose for the SRS group (<=13 Gy vs. >13 Gy) significantly influenced hearing preservation rates (p = 0.03). In the group of patients treated with SRS doses of <=13 Gy, cranial nerve toxicity was comparable to that of the FSRT group. Conclusions: FSRT and SRS are both safe and effective alternatives for the treatment of VS. Local control rates are comparable in both groups. SRS with doses of <=13 Gy is a safe alternative to FSRT. While FSRT can be applied safely for the treatment of VSs of all sizes, SRS should be reserved for smaller lesions.

  20. Mayak Worker Dosimetry System 2008 (MWDS-2008): assessment of internal dose from measurement results of plutonium activity in urine.

    PubMed

    Khokhryakov, Victor V; Khokhryakov, Valentin F; Suslova, Klara G; Vostrotin, Vadim V; Vvedensky, Vladimir E; Sokolova, Alexandra B; Krahenbuhl, Melinda P; Birchall, Alan; Miller, Scott C; Schadilov, Anatoly E; Ephimov, Alexander V

    2013-04-01

    A new modification of the prior human lung compartment plutonium model, Doses-2005, has been described. The modified model was named "Mayak Worker Dosimetry System-2008" (MWDS-2008). In contrast to earlier models developed for workers at the Mayak Production Association (Mayak PA), the new model more correctly describes plutonium biokinetics and metabolism in pulmonary lymph nodes. The MWDS-2008 also provides two sets of doses estimates: one based on bioassay data and the other based on autopsy data, where available. The algorithm of internal dose calculation from autopsy data will be described in a separate paper. Results of comparative analyses of Doses-2005 and MWDS-2008 are provided. Perspectives on the further development of plutonium dosimetry are discussed.

  1. Dose reduction efforts for pediatric head CT imaging in Washington State trauma centers: follow-up survey results.

    PubMed

    Graves, Janessa M; Kanal, Kalpana M; Rivara, Frederick P; Jarvik, Jeffrey G; Vavilala, Monica S

    2014-02-01

    To examine variation in pediatric trauma head CT imaging protocols in Washington State trauma centers (TCs) in 2012 and compare to a previous survey conducted in 2008-2009. A mixed-mode (online and paper) survey was sent to all adult and pediatric Washington State TCs (levels 1-5). Respondents provided information about the CT scanner used for pediatric head scans and technical information about pediatric dose reduction protocols. Mean head effective dose and organ dose for a female baby were estimated. Results were compared with previous data. Sixty-one of 76 TCs responded to the 2012 survey (response rate, 80.3%, versus 76% for 2008-2009 survey). In 2012, 91.7% reported having a dedicated pediatric protocol (87.7% in 2008-2009). Protective shielding use ranged from 80% to 100% across both survey years. In 2012, 2.5 times more TCs provided sufficient information to conduct dose calculations than in 2008-2009. Estimated mean CT dose index was 23.1 milliGray (mGy) in 2012, compared with 34.8 mGy in 2008-2009 (P = .01). Estimated mean dose length product was also significantly lower in 2012 than 2008-2009 (307.6 mGy × cm versus 430.1 mGy × cm, respectively; P = .04). Wide variation in mean effective dose was observed for level 3 and 4 TCs in 2012, similar to variation observed in 2008-2009 among level 4 TCs. Mean organ dose was significantly lower in 2012 for eye lens and brain, but higher for thyroid than in 2008-2009 (P < .05). Although most Washington State TCs employ dose reduction protocols for pediatric head CTs, and some measures were lower in 2012, variation in protocols use and estimated dose continues to exist. More complete responses in 2012 suggest improved understanding of the importance of pediatric dose reduction efforts. Education and institutional protocols are necessary to reduce pediatric radiation dose from head CTs. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  2. Statistical Comparison of Carcinogenic Effects and Dose-Response Relationships in Rats and Mice for 2,4-Toluene Diamine to those Ascribed to Toluene Diisocyanate

    PubMed Central

    Sielken, Robert L.; Bretzlaff, Robert S.; Valdez-Flores, Ciriaco; Parod, Ralph

    2012-01-01

    The U.S. National Toxicology Program (NTP) conducted 2-year bioassays of commercial grade toluene diisocyanate (TDI) (80% 2,4-TDI and 20% 2,6-TDI) and 2,4-toluene diamine (TDA) and concluded that both were carcinogenic in rodents. In the TDI study, there was an unproven but likely formation of TDA either because of flawed test-substance handling and storage conditions and/or the atypical exposure conditions employed. Although the carcinogenic responses in both studies were qualitatively similar, several statistical analyses were performed to substantiate this possibility more rigorously. Seven different statistical approaches combine to yield a robust and consistent conclusion that, if only a small fraction (approximately 5%) of the dose of TDI were hydrolyzed to TDA in the TDI study, then that would be sufficient to explain the observed carcinogenic responses in the TDI study. PMID:23172986

  3. Statistical Comparison of Carcinogenic Effects and Dose-Response Relationships in Rats and Mice for 2,4-Toluene Diamine to those Ascribed to Toluene Diisocyanate.

    PubMed

    Sielken, Robert L; Bretzlaff, Robert S; Valdez-Flores, Ciriaco; Parod, Ralph

    2012-11-01

    The U.S. National Toxicology Program (NTP) conducted 2-year bioassays of commercial grade toluene diisocyanate (TDI) (80% 2,4-TDI and 20% 2,6-TDI) and 2,4-toluene diamine (TDA) and concluded that both were carcinogenic in rodents. In the TDI study, there was an unproven but likely formation of TDA either because of flawed test-substance handling and storage conditions and/or the atypical exposure conditions employed. Although the carcinogenic responses in both studies were qualitatively similar, several statistical analyses were performed to substantiate this possibility more rigorously. Seven different statistical approaches combine to yield a robust and consistent conclusion that, if only a small fraction (approximately 5%) of the dose of TDI were hydrolyzed to TDA in the TDI study, then that would be sufficient to explain the observed carcinogenic responses in the TDI study.

  4. Blood phenylalanine concentrations in patients with PAH-deficient hyperphenylalaninaemia off diet without and with three different single oral doses of tetrahydrobiopterin: assessing responsiveness in a model of statistical process control.

    PubMed

    Lindner, M; Gramer, G; Garbade, S F; Burgard, P

    2009-08-01

    Tetrahydrobiopterin (BH(4)) cofactor loading is a standard procedure to differentiate defects of BH(4) metabolism from phenylalanine hydroxylase (PAH) deficiency. BH(4) responsiveness also exists in PAH-deficient patients with high residual PAH activity. Unexpectedly, single cases with presumed nil residual PAH activity have been reported to be BH(4) responsive, too. BH(4) responsiveness has been defined either by a >or=30% reduction of blood Phe concentration after a single BH(4) dose or by a decline greater than the individual circadian Phe level variation. Since both methods have methodological disadvantages, we present a model of statistical process control (SPC) to assess BH(4) responsiveness. Phe levels in 17 adult PKU patients of three phenotypic groups off diet were compared without and with three different single oral dosages of BH(4) applied in a double-blind randomized cross-over design. Results are compared for >or=30% reduction and SPC. The effect of BH(4) by >or=30% reduction was significant for groups (p < 0.01) but not for dose (p = 0.064), with no interaction of group with dose (p = 0.24). SPC revealed significant effects for group (p < 0.01) and the interaction for group with dose (p < 0.05) but not for dose alone (p = 0.87). After one or more loadings, seven patients would be judged to be BH(4) responsive either by the 30% criterion or by the SPC model, but only three by both. Results for patients with identical PAH genotype were not very consistent within (for different BH(4) doses) and between the two models. We conclude that a comparison of protein loadings without and with BH(4) combined with a standardized procedure for data analysis and decision would increase the reliability of diagnostic results.

  5. Methods used to calculate doses resulting from inhalation of Capstone depleted uranium aerosols.

    PubMed

    Miller, Guthrie; Cheng, Yung Sung; Traub, Richard J; Little, Tom T; Guilmette, Raymond A

    2009-03-01

    The methods used to calculate radiological and toxicological doses to hypothetical persons inside either a U.S. Army Abrams tank or Bradley Fighting Vehicle that has been perforated by depleted uranium munitions are described. Data from time- and particle-size-resolved measurements of depleted uranium aerosol as well as particle-size-resolved measurements of aerosol solubility in lung fluids for aerosol produced in the breathing zones of the hypothetical occupants were used. The aerosol was approximated as a mixture of nine monodisperse (single particle size) components corresponding to particle size increments measured by the eight stages plus the backup filter of the cascade impactors used. A Markov Chain Monte Carlo Bayesian analysis technique was employed, which straightforwardly calculates the uncertainties in doses. Extensive quality control checking of the various computer codes used is described.

  6. Whole organ and islet of Langerhans dosimetry for calculation of absorbed doses resulting from imaging with radiolabeled exendin

    PubMed Central

    van der Kroon, Inge; Woliner-van der Weg, Wietske; Brom, Maarten; Joosten, Lieke; Frielink, Cathelijne; Konijnenberg, Mark W.; Visser, Eric P.; Gotthardt, Martin

    2017-01-01

    Radiolabeled exendin is used for non-invasive quantification of beta cells in the islets of Langerhans in vivo. High accumulation of radiolabeled exendin in the islets raised concerns about possible radiation-induced damage to these islets in man. In this work, islet absorbed doses resulting from exendin-imaging were calculated by combining whole organ dosimetry with small scale dosimetry for the islets. Our model contains the tissues with high accumulation of radiolabeled exendin: kidneys, pancreas and islets. As input for the model, data from a clinical study (radiolabeled exendin distribution in the human body) and from a preclinical study with Biobreeding Diabetes Prone (BBDP) rats (islet-to-exocrine uptake ratio, beta cell mass) were used. We simulated 111In-exendin and 68Ga-exendin absorbed doses in patients with differences in gender, islet size, beta cell mass and radiopharmaceutical uptake in the kidneys. In all simulated cases the islet absorbed dose was small, maximum 1.38 mGy for 68Ga and 66.0 mGy for 111In. The two sources mainly contributing to the islet absorbed dose are the kidneys (33–61%) and the islet self-dose (7.5–57%). In conclusion, all islet absorbed doses are low (<70 mGy), so even repeated imaging will hardly increase the risk on diabetes. PMID:28067253

  7. Dose-response approaches for nuclear receptor-mediated modes of action for liver carcinogenicity: Results of a workshop.

    PubMed

    Andersen, Melvin E; Preston, R Julian; Maier, Andrew; Willis, Alison M; Patterson, Jacqueline

    2014-01-01

    A public workshop, organized by a Steering Committee of scientists from government, industry, universities and research organizations, was held at the National Institute of Environmental Health Sciences (NIEHS) in September, 2010. The workshop explored the dose-response implications of toxicant modes of action (MOA) mediated by nuclear receptors. The dominant paradigm in human health risk assessment has been linear extrapolation without a threshold for cancer, and estimation of sub-threshold doses for non-cancer and (in appropriate cases) cancer endpoints. However, recent publications question the application of dose-response modeling approaches with a threshold. The growing body of molecular toxicology information and computational toxicology tools has allowed for exploration of the presence or absence of sub-threshold doses for a number of receptor-mediated MOAs. The workshop explored the development of dose-response approaches for nuclear receptor-mediated liver cancer, within a MOA Human Relevance Framework (HRF). Case studies addressed activation of the AHR, the CAR and the PPARα. This article describes the workshop process, key issues discussed and conclusions. The value of an interactive workshop approach to apply current MOA/HRF frameworks was demonstrated. The results may help direct research on the MOA and dose-response of receptor-based toxicity, since there are commonalities for many receptors in the basic pathways involved for late steps in the MOA, and similar data gaps in early steps. Three additional papers in this series describe the results and conclusions for each case-study receptor regarding its MOA, relevance of the MOA to humans and the resulting dose-response implications.

  8. Agreement between different parameters of dialysis dose in achieving treatment targets: results from the NECOSAD study.

    PubMed

    Moret, Karin E; Grootendorst, Diana C; Dekker, Friedo W; Boeschoten, Elizabeth W; Krediet, Raymond T; Houterman, Saskia; Beerenhout, Charles H; Kooman, Jeroen P

    2012-03-01

    The recommended parameter of dialysis dose differs between K-DOQI and the European Best Practice Guidelines. It is not well known to what extent an agreement exists between the different parameters, nor if target and delivered dialysis dose are prescribed according to the urea reduction rate (URR), single-pool Kt/V (spKt/V) or equilibrated double-pool Kt/V (eKt/V) and which parameter is most strongly related to mortality. In 830 haemodialysis patients from the NECOSAD cohort URR, spKt/V and eKt/V were calculated and compared according to a classification regarding the recommended treatment targets (70%, 1.4 and 1.2, respectively) as well as minimum delivered dialysis dose (65%, 1.2 and 1.05, respectively). Moreover, the relation between treatment dose and survival was assessed using Cox regression analysis. A spKt/V of ≥1.4 and URR ≥70% corresponded with eKt/V ≥1.20 (as reference method) in, respectively, 98.0 and 90.6% of patients. spKt/V of ≥1.2 and URR ≥65% corresponded with eKt/V ≥1.05 in, respectively, 95.5 and 91.2% of patients. Deviations from the reference method were significantly related to differences in urea distribution volume (spKt/V), treatment time (URR) and ultrafiltration volume (URR). The adjusted HR (95% CI) was 0.98 (0.96, 0.99) for URR, 0.51 (0.31, 0.84) for spKt/V and 0.46 (0.30, 0.80) for the eKt/V. The use of URR leads to larger disagreement with the reference method (eKt/V) treatment target as compared to spKt/V. Low urea distribution volume, short treatment time and low ultrafiltration volumes are predictive parameters for overestimation of dialysis dose when utilizing the alternative methods spKt/V and URR instead of eKt/V. Delivered eKt/V, spKt/V and URR were all positively related to survival.

  9. CRITICAL HEIGHT FOR THE DESTABILIZATION OF SOLAR PROMINENCES: STATISTICAL RESULTS FROM STEREO OBSERVATIONS

    SciTech Connect

    Liu Kai; Wang Yuming; Wang Shui; Shen Chenglong

    2012-01-10

    At which height is a prominence inclined to be unstable, or where is the most probable critical height for the prominence destabilization? This question was statistically studied based on 362 solar limb prominences well recognized by Solar Limb Prominence Catcher and Tracker from 2007 April to the end of 2009. We found that there are about 71% disrupted prominences (DPs), among which about 42% of them did not erupt successfully and about 89% of them experienced a sudden destabilization process. After a comprehensive analysis of the DPs, we discovered the following: (1) Most DPs become unstable at a height of 0.06-0.14 R{sub Sun} from the solar surface, and there are two most probable critical heights at which a prominence is very likely to become unstable, the first one is 0.13 R{sub Sun} and the second one is 0.19 R{sub Sun }. (2) An upper limit for the erupting velocity of eruptive prominences (EPs) exists, which decreases following a power law with increasing height and mass; accordingly, the kinetic energy of EPs has an upper limit too, which decreases as the critical height increases. (3) Stable prominences are generally longer and heavier than DPs, and not higher than 0.4 R{sub Sun }. (4) About 62% of the EPs were associated with coronal mass ejections (CMEs); but there is no difference in apparent properties between EPs associated with CMEs and those that are not.

  10. Exploring 100+ Year Variability with DASCH: Statistical Methods and Recent Results.

    NASA Astrophysics Data System (ADS)

    Miller, George Franklin; Grindlay, Jonathan E.; Los, Edward

    2014-06-01

    The Digital Access to a Sky Century at Harvard (DASCH) project is currently digitizing the roughly 500,000 photographic plates maintained by the Harvard College Observatory. The Harvard plate collection covers each point of the sky roughly 500 to 3000 times from 1885 to 1992, with limiting magnitudes ranging from B=14-18 mag and photometric accuracy within ±0.1 mag. Production scanning (roughly 400 plates/day) is proceeding in Galactic coordinates from the North Galactic Pole and is currently at roughly 40 degrees galactic latitude. The vastness of these data makes DASCH unique in its ability to systematically study variability on decade-long time scales across the entire sky. We are developing new statistical mining techniques to predictively identify the many classes of stellar variability and explore their long-term behavior, as well as discover new unusual cases/classes of variability. Most recently, we are working to implement wavelet-based algorithms into our mining routines, better allowing us to analyze localized non-periodic signals. Here we report on the progress of our mining and machine learning routines, as well as share several of the exciting new discoveries that are being made with DASCH. We gratefully acknowledge support from NSF grants AST-0407380, AST-0909073 and AST-1313370.

  11. Some results on the statistics of hull perimeters in large planar triangulations and quadrangulations

    NASA Astrophysics Data System (ADS)

    Guitter, Emmanuel

    2016-11-01

    The hull perimeter at distance d in a planar map with two marked vertices at distance k from each other is the length of the closed curve separating these two vertices and lying at distance d from the first one (d\\lt k). We study the statistics of hull perimeters in large random planar triangulations and quadrangulations as a function of both k and d. Explicit expressions for the probability density of the hull perimeter at distance d, as well as for the joint probability density of hull perimeters at distances d 1 and d 2, are obtained in the limit of infinitely large k. We also consider the situation where the distance d at which the hull perimeter is measured corresponds to a finite fraction of k. The various laws that we obtain are identical for triangulations and for quadrangulations, up to a global rescaling. Our approach is based on recursion relations recently introduced by the author which determine the generating functions of so-called slices, i.e. pieces of maps with appropriate distance constraints. It is indeed shown that the map decompositions underlying these recursion relations are intimately linked to the notion of hull perimeters and provide a simple way to fully control them.

  12. Dose reduction efforts for pediatric head CT imaging in Washington State trauma centers: follow-up survey results

    PubMed Central

    Kanal, Kalpana M.; Rivara, Frederick P.; Jarvik, Jeffrey G.; Vavilala, Monica S.

    2014-01-01

    Purpose To examine variation in pediatric trauma head CT imaging protocols in Washington State trauma centers (TCs) in 2012 and compare to a previous survey conducted in 2008/09. Methods A mixed-mode (online and paper) survey was sent to all adult and pediatric Washington State TCs (levels 1–5). Respondents provided information about the CT scanner used for pediatric head scans and technical information about pediatric dose reduction protocols. Mean head effective dose and organ dose for a female baby were estimated. Results were compared to previous data. Results Sixty-one of 76 TCs responded to the 2012 survey (response rate 80.3%; response rate in 2008/09 survey was 76%). In 2012, 91.7% reported having a dedicated pediatric protocol (87.7% in 2008/09). Protective shielding use ranged from 80 to 100% across both survey years. In 2012, 2.5 times more TCs provided sufficient information to conduct dose calculations than in 2008/09. Estimated mean CTDIvol was 23.1 mGy in 2012, compared to 34.8 mGy in 2008/09 (p=0.01). Estimated mean DLP was also significantly lower in 2012 than 2009/08 (307.6 mGy*cm vs. 430.1 mGy*cm, respectively; p=0.04). Wide variation in mean effective dose was observed for level 3 and 4 TCs in 2012, similar to variation observed in 2008/09 among level 4 TCs. Mean organ dose was significantly lower in 2012 for eye lens and brain, but higher for thyroid than 2008/09 (p<0.05). Conclusions While most Washington State TCs employ dose reduction protocols for pediatric head CTs, and some measures were lower in 2012, variation in protocols use and estimated dose continues to exist. More complete responses in 2012 suggest improved understanding of the importance of pediatric dose reduction efforts. Education and institutional protocols are necessary to reduce pediatric radiation dose from head CTs. PMID:24360905

  13. Dumb-bell galaxies in southern clusters: Catalog and preliminary statistical results

    NASA Technical Reports Server (NTRS)

    Vettolani, G.; Gregorini, L.; Parma, P.; Deruiter, H. R.

    1990-01-01

    The dominant galaxy of a rich cluster is often an object whose formation and evolution is closely connected to the dynamics of the cluster itself. Hoessel (1980) and Schneider et al. (1983) estimate that 50 percent of the dominant galaxies are either of the dumb-bell type or have companions at projected distances less than 20 kpc, which is far in excess of the number expected from chance projection (see also Rood and Leir 1979). Presently there is no complete sample of these objects, with the exception of the listing of dumb-bell galaxies in BM type I and I-II clusters in the Abell statistical sample of Rood and Leir (1979). Recent dynamical studies of dumb-bell galaxies in clusters (Valentijn and Casertano, 1988) still suffer from inhomogeneity of the sample. The fact that it is a mixture of optically and radio selected objects may have introduced an unknown biases, for instance if the probability of radio emission is enhanced by the presence of close companions (Stocke, 1978, Heckman et al. 1985, Vettolani and Gregorini 1988) a bias could be present in their velocity distribution. However, this situation is bound to improve: a new sample of Abell clusters in the Southern Hemisphere has been constructed (Abell et al., 1988 hereafter ACO), which has several advantages over the original northern catalog. The plate material (IIIaJ plates) is of better quality and reaches fainter magnitudes. This makes it possible to classify the cluster types with a higher degree of accuracy, as well as to fainter magnitudes. The authors therefore decided to reconsider the whole problem constructing a new sample of dumb-bell galaxies homogeneously selected from the ACO survey. Details of the classification criteria are given.

  14. Monochromatic x-rays for low-dose digital mammography: preliminary results.

    PubMed

    Yoon, Kwon-Ha; Kwon, Young Man; Choi, Byoung-Jung; Son, Hyun Hwa; Ryu, Cheol Woo; Chon, Kwon Su; Park, Seong Hoon; Juhng, Sun Kwan

    2012-12-01

    The feasibility of using monochromatic x-ray imaging generated from an x-ray tube and a multilayer reflector for digital mammography with a low radiation dose was examined. A multilayer mirror was designed to select the x-ray peak with an energy of 21.5 keV generated from an x-ray tube with a tungsten target and was fabricated by the ion-beam sputtering deposition system. Monochromatic x-ray images were obtained from an experimental digital mammography setup with a scanning stage. The performance of the system was evaluated using a breast phantom, a spectrometer, and a radiation dosimeter. We measured the contrast-to-noise ratio and performed the 10% modulation function test to determine image quality and resolution. The monochromatic beam from the multilayer reflector had a full-width-at-half-maximum of 0.9 keV at 21.5 keV, and the reflectivity was 0.70, which was 90% of the designed value. The polychromatic and monochromatic x-rays showed radiation doses of 0.497 and 0.0415 mGy, respectively. The monochromatic x-ray image shows fibers, calcifications, and masses more clearly than the polychromatic x-ray images do. The image contrast of the monochromatic x-rays was 1.85 times higher than that of the polychromatic x-rays. The experimental mammography setup had a spatial resolution of 7 lp/mm with both x-rays. Monochromatic x-rays generated using a multilayer mirror may be a useful diagnostic tool for breast examination by providing high contrast imaging with a low radiation dose.

  15. Long-term results of low dose total body irradiation for advanced non-Hodgkin lymphoma.

    PubMed

    Lybeert, M L; Meerwaldt, J H; Deneve, W

    1987-08-01

    Sixty-eight patients received fractionated low dose total body irradiation (LTBI) as treatment for non-Hodgkin lymphoma (NHL) at the Rotterdamsch Radio-Therapeutisch Instituut (RRTI) in the period 1973-1979. Ninety percent (61/68) of these patients had advanced disease (Stage III + IV). According to current malignancy grade classifications, 34 patients had low grade NHL, 10 intermediate, and 19 high grade. In 5 cases no exact grading was possible. LTBI was given 3 times a week, midline dose 0.1 Gy, using 6 or 25 MeV photons to a mean total dose of 1.78 Gy. Initial response rate for low, intermediate, and high grade NHL was resp. 84, 42, and 40%. The main prognostic factor for survival and recurrence-free survival (RFS) was malignancy grade. Probability of uncorrected survival at 10 years for low, intermediate, and high grade was resp. 34, 0 and 0%. Probability of RFS at 10 years was resp. 19, 0, and 0%. Neither stage nor sex had any influence on survival. Age was reversely correlated with survival, but was not correlated with RFS. Influence of prior therapy (18 patients) on survival and RFS was separately analyzed. Neither survival nor RFS of unfavorable histologic type NHL (high and intermediate grade) was influenced. On the other hand patients with a favorable histologic type NHL (low grade) had a significantly (p less than 0.05) better RFS if they received LTBI as initial treatment, but survival was not significantly influenced. RFS at 5 and 10 years of patients who received LTBI as first treatment was respectively 32% and 27%. No treatment related complications were noted. Subsequent chemotherapy in case of relapse was not hampered by previous LTBI. The high response rate and extended RFS, without maintenance therapy, makes LTBI a preferable first line treatment for patients with advanced stage low grade NHL.

  16. How to interpret the results of medical time series data analysis: Classical statistical approaches versus dynamic Bayesian network modeling

    PubMed Central

    Onisko, Agnieszka; Druzdzel, Marek J.; Austin, R. Marshall

    2016-01-01

    Background: Classical statistics is a well-established approach in the analysis of medical data. While the medical community seems to be familiar with the concept of a statistical analysis and its interpretation, the Bayesian approach, argued by many of its proponents to be superior to the classical frequentist approach, is still not well-recognized in the analysis of medical data. Aim: The goal of this study is to encourage data analysts to use the Bayesian approach, such as modeling with graphical probabilistic networks, as an insightful alternative to classical statistical analysis of medical data. Materials and Methods: This paper offers a comparison of two approaches to analysis of medical time series data: (1) classical statistical approach, such as the Kaplan–Meier estimator and the Cox proportional hazards regression model, and (2) dynamic Bayesian network modeling. Our comparison is based on time series cervical cancer screening data collected at Magee-Womens Hospital, University of Pittsburgh Medical Center over 10 years. Results: The main outcomes of our comparison are cervical cancer risk assessments produced by the three approaches. However, our analysis discusses also several aspects of the comparison, such as modeling assumptions, model building, dealing with incomplete data, individualized risk assessment, results interpretation, and model validation. Conclusion: Our study shows that the Bayesian approach is (1) much more flexible in terms of modeling effort, and (2) it offers an individualized risk assessment, which is more cumbersome for classical statistical approaches. PMID:28163973

  17. Safety of the first dose of fingolimod for multiple sclerosis: results of an open-label clinical trial

    PubMed Central

    2014-01-01

    Background In patients with relapsing-remitting MS (RRMS) fingolimod prevents disease relapses and delays disability progression. First dose administration of fingolimod is associated with a transient, dose-dependent decrease in heart rate (HR) in the 6 hours after drug intake. The aim of the study is to to assess safety and tolerability of the first dose of fingolimod in a cohort of Italian patients with RRMS without alternative therapeutic options. Methods Open-label, single arm, multicentre study. After the first dose of fingolimod, patients were observed for 6 hours and had their vital signs monitored hourly. Extended on-site monitoring was provided when required. Results Of the 906 patients enrolled in the study, most (95.2%) did not experience any adverse event (AE) following fingolimod administration. Cardiovascular AEs occurred in 18 patients and included bradycardia (1.3%), first-and second-degree atrioventricular block (0.1% and 0.2%), palpitations (0.1%), sinus arrhythmia (0.1%) and ventricular premature beats (0.1%). All events were self-limiting and did not require any intervention. Extended monitoring was required in 34 patients. Conclusions These results, in a population who better resembled real-world clinical practice in terms of concomitant diseases and medications, are consistent with previous clinical trials and confirmed that the first dose administration of fingolimod is generally safe and well tolerated. Trial registration EudraCT 2011-000770-60 PMID:24690227

  18. Why publishing everything is more effective than selective publishing of statistically significant results.

    PubMed

    van Assen, Marcel A L M; van Aert, Robbie C M; Nuijten, Michèle B; Wicherts, Jelte M

    2014-01-01

    De Winter and Happee examined whether science based on selective publishing of significant results may be effective in accurate estimation of population effects, and whether this is even more effective than a science in which all results are published (i.e., a science without publication bias). Based on their simulation study they concluded that "selective publishing yields a more accurate meta-analytic estimation of the true effect than publishing everything, (and that) publishing nonreplicable results while placing null results in the file drawer can be beneficial for the scientific collective" (p.4). Using their scenario with a small to medium population effect size, we show that publishing everything is more effective for the scientific collective than selective publishing of significant results. Additionally, we examined a scenario with a null effect, which provides a more dramatic illustration of the superiority of publishing everything over selective publishing. Publishing everything is more effective than only reporting significant outcomes.

  19. Results of autologous transplantation in lymphoma are not improved by increasing the dose of etoposide in the BEAM regimen: a single-centre sequential-cohort study.

    PubMed

    Martín, A; Caballero, M D; Pérez-Simón, J A; López-Holgado, N; Mateos, M V; Cañizo, M C; Miguel, J F San

    2004-10-01

    We have undertaken a retrospective sequential-cohort analysis of 131 lymphoma patients treated with the BEAM regimen and autologous stem cell transplantation, to compare BEAM at standard doses (sBEAM; n = 67 from May 1990 to April 1995) and BEAM with escalated etoposide dose from 800 to 1600 mg/m(2) (eBEAM; n = 64 from May 1995 to June 1999). Transplant-related mortality and incidence of secondary malignancies were similar in both groups. Disease progression was significantly lower in indolent lymphoma (IL) patients receiving eBEAM (7 vs 43%), although survival was comparable due to a higher toxic mortality in the eBEAM group. The 5-year event-free survival and overall survival were better in Hodgkin's disease (HD) patients treated with eBEAM (70 and 77%, respectively) compared to sBEAM (58 and 69%, respectively), but the difference was not statistically significant. In aggressive lymphomas, no difference was detected between groups. Our results indicate that while escalation of the etoposide doses in the BEAM conditioning regimen does not appear to improve outcome, encouraging results in IL and HD may warrant further studies.

  20. A method for calculating Bayesian uncertainties on internal doses resulting from complex occupational exposures.

    PubMed

    Puncher, M; Birchall, A; Bull, R K

    2012-08-01

    Estimating uncertainties on doses from bioassay data is of interest in epidemiology studies that estimate cancer risk from occupational exposures to radionuclides. Bayesian methods provide a logical framework to calculate these uncertainties. However, occupational exposures often consist of many intakes, and this can make the Bayesian calculation computationally intractable. This paper describes a novel strategy for increasing the computational speed of the calculation by simplifying the intake pattern to a single composite intake, termed as complex intake regime (CIR). In order to assess whether this approximation is accurate and fast enough for practical purposes, the method is implemented by the Weighted Likelihood Monte Carlo Sampling (WeLMoS) method and evaluated by comparing its performance with a Markov Chain Monte Carlo (MCMC) method. The MCMC method gives the full solution (all intakes are independent), but is very computationally intensive to apply routinely. Posterior distributions of model parameter values, intakes and doses are calculated for a representative sample of plutonium workers from the United Kingdom Atomic Energy cohort using the WeLMoS method with the CIR and the MCMC method. The distributions are in good agreement: posterior means and Q(0.025) and Q(0.975) quantiles are typically within 20 %. Furthermore, the WeLMoS method using the CIR converges quickly: a typical case history takes around 10-20 min on a fast workstation, whereas the MCMC method took around 12-72 hr. The advantages and disadvantages of the method are discussed.

  1. Measurements of natural radioactivity and the resulting radiation doses from commercial granites.

    PubMed

    Aydarous, A Sh; Zeghib, Sadek; Al-Dughmah, Mohammed

    2010-12-01

    Saudi Arabia is becoming a relatively large market for local and foreign marble and granite use in dwellings. Due to increasing concern about environmental radiological protection, different types of locally widely used granite tiles were collected from different suppliers in the Jeddah province, Saudi Arabia. The analysis for these granite tiles for gamma radiation was conducted by means of a high-resolution HPGe gamma-spectroscopy system. The activity concentrations of (232)Th, (226)Ra and 40K in the selected granite samples ranged from 4.9 to 144, 9.7 to 133 and 168 to 1806 Bq kg(-1), respectively. The data were compared with other granite types and building materials used all over the world. The absorbed dose rates, effective dose rates, radium equivalent activities as well as the radiation hazard indices were estimated. The radium equivalent activities (Ra(eq)) are lower than the limit of 370 Bq kg(-1) set by the Organisation for Economic Cooperation and Development (Exposure to radiation from the natural radioactivity in building materials. Report by a Group of Experts of the OECD, Nuclear Energy Agency, OECD, Paris, 1979) except in three samples.

  2. Stringent test of the statistical quasiclassical trajectory model for the H+3 exchange reaction: a comparison with rigorous statistical quantum mechanical results.

    PubMed

    Aoiz, F J; González-Lezana, T; Sáez Rábanos, V

    2007-11-07

    A complete formulation of a statistical quasiclassical trajectory (SQCT) model is presented in this work along with a detailed comparison with results obtained with the statistical quantum mechanical (SQM) model for the H+ +D2 and H+ +H2 reactions. The basic difference between the SQCT and the SQM models lies in the fact that trajectories instead of wave functions are propagated in the entrance and exit channels. Other than this the two formulations are entirely similar and both comply with the principle of detailed balance and conservation of parity. Reaction probabilities, and integral and differential cross sections (DCS's) for these reactions at different levels of product's state resolution and from various initial states are shown and discussed. The agreement is in most cases excellent and indicates that the effect of tunneling through the centrifugal barrier is negligible. Some differences are found, however, between state resolved observables calculated by the SQCT and the SQM methods which makes use of the centrifugal sudden (coupled states) approximation (SQM-CS). When this approximation is removed and the full close coupling treatment is used in the SQM model (SQM-CC), an almost perfect agreement is achieved. This shows that the SQCT is sensitive enough to show the relatively small inaccuracies resulting from the decoupling inherent to the CS approximation. In addition, the effect of ignoring the parity conservation is thoroughly examined. This effect is in general minor except in particular cases such as the DCS from initial rotational state j=0. It is shown, however, that in order to reproduce the sharp forward and backward peaks the conservation of parity has to be taken into account.

  3. Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

    NASA Astrophysics Data System (ADS)

    Renis, M.; Borghesi, M.; Favetta, M.; Malfa, G.; Manti, L.; Romano, F.; Schettino, G.; Tomasello, B.; Cirrone, G. A. P.

    2013-07-01

    Studies regarding the radiobiological effects of low dose radiation, microbeam irradiation services have been developed in the world and today laser acceleration of protons and heavy ions may be used in radiation therapy. The application of different facilities is essential for studying bystander effects and relating signalling phenomena in different cells or tissues. In particular the use of ion beams results advantageous in cancer radiotherapy compared to more commonly used X-rays, since the ability of ions in delivering lethal amount of doses into the target tumour avoiding or limiting damage to the contiguous healthy tissues. At the INFN-LNS in Catania, a multidisciplinary radiobiology group is strategically structured aimed to develop radiobiological research, finalised to therapeutic applications, compatible with the use of high dose laser-driven ion beams. The characteristic non-continuous dose rates with several orders of magnitude of laser-driven ion beams makes this facility very interesting in the cellular systems' response to ultra-high dose rates with non-conventional pulse time intervals cellular studies. Our group have projected to examine the effect of high dose laser-driven ion beams on two cellular types: foetal fibroblasts (normal control cells) and DU145 (prostate cancer cells), studying the modulation of some different bio-molecular parameters, in particular cell proliferation and viability, DNA damage, redox cellular status, morphological alterations of both the cytoskeleton components and some cell organelles and the possible presence of apoptotic or necrotic cell death. Our group performed preliminary experiments with high energy (60 MeV), dose rate of 10 Gy/min, doses of 1, 2, 3 Gy and LET 1 keV/μm on human foetal fibroblasts (control cells). We observed that cell viability was not influenced by the characteristics of the beam, the irradiation conditions or the analysis time. Conversely, DNA damage was present at time 0, immediately

  4. Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

    SciTech Connect

    Renis, M.; Malfa, G.; Tomasello, B.; Borghesi, M.; Schettino, G.; Favetta, M.; Romano, F.; Cirrone, G. A. P.; Manti, L.

    2013-07-26

    Studies regarding the radiobiological effects of low dose radiation, microbeam irradiation services have been developed in the world and today laser acceleration of protons and heavy ions may be used in radiation therapy. The application of different facilities is essential for studying bystander effects and relating signalling phenomena in different cells or tissues. In particular the use of ion beams results advantageous in cancer radiotherapy compared to more commonly used X-rays, since the ability of ions in delivering lethal amount of doses into the target tumour avoiding or limiting damage to the contiguous healthy tissues. At the INFN-LNS in Catania, a multidisciplinary radiobiology group is strategically structured aimed to develop radiobiological research, finalised to therapeutic applications, compatible with the use of high dose laser-driven ion beams. The characteristic non-continuous dose rates with several orders of magnitude of laser-driven ion beams makes this facility very interesting in the cellular systems' response to ultra-high dose rates with non-conventional pulse time intervals cellular studies. Our group have projected to examine the effect of high dose laser-driven ion beams on two cellular types: foetal fibroblasts (normal control cells) and DU145 (prostate cancer cells), studying the modulation of some different bio-molecular parameters, in particular cell proliferation and viability, DNA damage, redox cellular status, morphological alterations of both the cytoskeleton components and some cell organelles and the possible presence of apoptotic or necrotic cell death. Our group performed preliminary experiments with high energy (60 MeV), dose rate of 10 Gy/min, doses of 1, 2, 3 Gy and LET 1 keV/μm on human foetal fibroblasts (control cells). We observed that cell viability was not influenced by the characteristics of the beam, the irradiation conditions or the analysis time. Conversely, DNA damage was present at time 0, immediately

  5. An application of combining results from multiple methods—statistical evaluation of uncertainty for NIST SRM 1508a

    NASA Astrophysics Data System (ADS)

    Hornikova, A.; Zhang, N. F.; Welch, M. J.; Tai, S.

    2006-06-01

    NIST standard reference materials (SRMs) are certified reference materials that are developed at NIST and provided to laboratories (industry, government and academia) for assessment and improvement of measurement quality. This paper details the statistical analysis related to the recertification of SRM 1508a, benzoylecgonine (cocaine metabolite) in freeze-dried urine, to incorporate new data. The recertification is based on combining measurement results from different measurement methods and time periods. Several different statistical models and corresponding estimators were considered for the certified value, its standard uncertainty and its expanded uncertainty.

  6. Why Publishing Everything Is More Effective than Selective Publishing of Statistically Significant Results

    PubMed Central

    van Assen, Marcel A. L. M.; van Aert, Robbie C. M.; Nuijten, Michèle B.; Wicherts, Jelte M.

    2014-01-01

    Background De Winter and Happee [1] examined whether science based on selective publishing of significant results may be effective in accurate estimation of population effects, and whether this is even more effective than a science in which all results are published (i.e., a science without publication bias). Based on their simulation study they concluded that “selective publishing yields a more accurate meta-analytic estimation of the true effect than publishing everything, (and that) publishing nonreplicable results while placing null results in the file drawer can be beneficial for the scientific collective” (p.4). Methods and Findings Using their scenario with a small to medium population effect size, we show that publishing everything is more effective for the scientific collective than selective publishing of significant results. Additionally, we examined a scenario with a null effect, which provides a more dramatic illustration of the superiority of publishing everything over selective publishing. Conclusion Publishing everything is more effective than only reporting significant outcomes. PMID:24465448

  7. How to interpret the results of medical time series data analysis: Classical statistical approaches versus dynamic Bayesian network modeling.

    PubMed

    Onisko, Agnieszka; Druzdzel, Marek J; Austin, R Marshall

    2016-01-01

    Classical statistics is a well-established approach in the analysis of medical data. While the medical community seems to be familiar with the concept of a statistical analysis and its interpretation, the Bayesian approach, argued by many of its proponents to be superior to the classical frequentist approach, is still not well-recognized in the analysis of medical data. The goal of this study is to encourage data analysts to use the Bayesian approach, such as modeling with graphical probabilistic networks, as an insightful alternative to classical statistical analysis of medical data. This paper offers a comparison of two approaches to analysis of medical time series data: (1) classical statistical approach, such as the Kaplan-Meier estimator and the Cox proportional hazards regression model, and (2) dynamic Bayesian network modeling. Our comparison is based on time series cervical cancer screening data collected at Magee-Womens Hospital, University of Pittsburgh Medical Center over 10 years. The main outcomes of our comparison are cervical cancer risk assessments produced by the three approaches. However, our analysis discusses also several aspects of the comparison, such as modeling assumptions, model building, dealing with incomplete data, individualized risk assessment, results interpretation, and model validation. Our study shows that the Bayesian approach is (1) much more flexible in terms of modeling effort, and (2) it offers an individualized risk assessment, which is more cumbersome for classical statistical approaches.

  8. Do intervention fidelity and dose influence outcomes? Results from the move to improve worksite physical activity program.

    PubMed

    Wilson, Mark G; Basta, Tania B; Bynum, Bethany H; DeJoy, David M; Vandenberg, Robert J; Dishman, Rod K

    2010-04-01

    The purpose of this paper is to evaluate the implementation of the Move to Improve worksite physical activity program using a four step framework that includes the following: (i) defining the active ingredients, (ii) using good methods to measure implementation, (iii) monitoring implementation and (iv) relating implementation to outcomes. The intervention active ingredients consisted of a goal setting behavior change program, a team competition and environmental supports. Intervention fidelity and dose were measured by surveys administered to site co-ordinators, team captains and employees. Implementation was monitored by the use of biweekly assessments that tracked individual physical activity levels and through weekly reports of the project director and site co-ordinators. Latent growth modeling was conducted to determine whether intervention outcomes were affected by site implementation (i.e. fidelity) and/or participation by employees (i.e. dose). Results showed high levels of intervention fidelity, moderate to high levels of intervention dose delivered and moderate levels of the intervention dose received. Level of implementation affected the degree of change in vigorous physical activity (Mean = 5.4 versus 2.2; chi(2) = 4.9, df = 1), otherwise outcome measures were unaffected by fidelity and dose. These findings suggest that practitioners should focus more energy assuring that the core components are fully implemented and be less concerned about the level of participation.

  9. The dipeptidyl peptidase-4 inhibitor linagliptin exhibits time- and dose-dependent localization in kidney, liver, and intestine after intravenous dosing: results from high resolution autoradiography in rats.

    PubMed

    Greischel, Andreas; Binder, Rudolf; Baierl, Juergen

    2010-09-01

    Linagliptin is an orally active dipeptidyl peptidase-4 (DPP-4) inhibitor that is under development for the treatment of type 2 diabetes and shows dose-dependent pharmacokinetics in rats and humans. With microscopic autoradiography, the dose dependence of cellular distribution of [(3)H]linagliptin-related radioactivity was investigated in kidney at 3 h after intravenous injection of 7.4, 100, and 2000 microg/kg [(3)H]linagliptin. Furthermore, distribution of radioactivity in kidney, liver, and small intestine was investigated in relation to time (2 min, 3 h, and 192 h) after intravenous injection of 7.4 microg/kg [(3)H]linagliptin. The localization of radioactivity in the kidney at 3 h after administration of 7.4, 100, and 2000 microg/kg [(3)H]linagliptin changed with increasing dose from cortical glomeruli and parts of proximal tubule parts to parts of medullar proximal tubule. In addition, the compound distribution in the kidney shifted with time after administration of 7.4 microg/kg [(3)H]linagliptin from glomeruli (2 min) to the lower parts of proximal tubules (192 h). The radioactivity within proximal tubules was located primarily in the brush border. In the liver, the radioactivity persisted mainly around the portal triads and in the bile duct from 2 min to 192 h. In the small intestine, the radioactivity shifted from the lamina propria (2 min) to the surface of the villi and/or intestinal lumen (192 h). In conclusion, the cellular distribution pattern of [(3)H]linagliptin-related radioactivity reflected the known distribution of DPP-4. Together with the persistence of binding, this result supports the high relevance of DPP-4 binding of linagliptin for its pharmacokinetics and pharmacodynamics.

  10. Acute Exposure to High Dose γ-Radiation Results in Transient Activation of Bone Lining Cells

    PubMed Central

    Turner, Russell T.; Iwaniec, Urszula T.; Wong, Carmen P.; Lindenmaier, Laurence B.; Wagner, Lindsay A.; Branscum, Adam J.; Menn, Scott A.; Taylor, James; Zhang, Ye; Wu, Honglu; Sibonga, Jean D.

    2014-01-01

    The present studies investigated the cellular mechanisms for the detrimental effects of high dose whole body γ-irradiation on bone. In addition, radioadaptation and bone marrow transplantation were assessed as interventions to mitigate the skeletal complications of irradiation. Increased trabecular thickness and separation and reduced fractional cancellous bone volume, connectivity density, and trabecular number were detected in proximal tibia and lumbar vertebra 14 days following γ-irradiation with 6 Gy. To establish the cellular mechanism for the architectural changes, vertebrae were analyzed by histomorphometry 1, 3, and 14 days following irradiation. Marrow cell density decreased within 1 day (67% reduction, p<0.0001), reached a minimum value after 3 days (86% reduction, p<0.0001), and partially rebounded by 14 days (30% reduction, p=0.0025) following irradiation. In contrast, osteoblast-lined bone perimeter was increased by 290% (1 day, p=0.04), 1230% (3 days, p<0.0001), and 530% (14 days, p=0.003), respectively. There was a strong association between radiation-induced marrow cell death and activation of bone lining cells to express the osteoblast phenotype (Pearson correlation −0.85, p<0.0001). An increase (p=0.004) in osteoclast-lined bone perimeter was also detected with irradiation. A priming dose of γ-radiation (0.5 mGy), previously shown to reduce mortality, had minimal effect on the cellular responses to radiation and did not prevent detrimental changes in bone architecture. Bone marrow transplantation normalized marrow cell density, bone turnover, and most indices of bone architecture following irradiation. In summary, radiation-induced death of marrow cells is associated with 1) a transient increase in bone formation due, at least in part, to activation of bone lining cells, and 2) an increase in bone resorption due to increased osteoclast perimeter. Bone marrow transplantation is effective in mitigating the detrimental effects of acute exposure

  11. Active Learning in Large Classes: Can Small Interventions Produce Greater Results than Are Statistically Predictable?

    ERIC Educational Resources Information Center

    Adrian, Lynne M.

    2010-01-01

    Six online postings and six one-minute papers were added to an introductory first-year class, forming 5 percent of the final grade, but represented significant intervention in class functioning and amount of active learning. Active learning produced results in student performance beyond the percentage of the final grade it constituted. (Contains 1…

  12. Treatment results of high dose cabergoline as an adjuvant therapy in six patients with established severe ovarian hyper stimulation syndrome

    PubMed Central

    Saharkhiz, Nasrin; Akbari Sene, Azadeh; Salehpour, Saghar; Tamimi, Maryam; Vasheghani Farahani, Masoumeh; Sheibani, Kourosh

    2014-01-01

    Background: The beneficial role of cabergoline as a prophylactic agent to prevent ovarian hyper stimulation syndrome (OHSS) among high-risk patients has been demonstrated in previous studies. But data for its role as a treatment for established severe OHSS is still limited. We represent the treatment results of high dose oral cabergoline in management of six patients after the syndrome is established. Case: High-dose oral cabergoline (1 mg daily for eight days) was prescribed as an adjuvant to symptomatic treatment for six hospitalized patients with established severe OHSS following infertility treatment cycles. In two cases OHSS resolved rapidly despite the occurrence of ongoing pregnancy. Conclusion: Considering the treatment outcomes of our patients, high dose cabergoline did not eliminate the need for traditional treatments, but it was a relatively effective and safe therapy in management of established severe OHSS, and prevented the increase in its severity following the occurrence of pregnancy. PMID:25469130

  13. A low dose-fractionation shceme for the radiotherapy of carcinoma of the bladder. Experimental background and preliminary results.

    PubMed

    Littbrand, B; Edsmyr, F; Révész, L

    1975-01-01

    Experimental observations are described which form the basis of a low dose-fractionation scheme designed in an attempt to circumvent the problem presented for radiotherapy by the particular radioresistance of poorly oxygenated cells. In a preliminary investigation the scheme was tested in the treatment of carcinoma of the bladder. A total of 45 patients were included in the trial, randomized to be treated according to either of two fractionation schemes. Scheme I : 100 rad 3 times a day, 5 days a week, a total tumor dose of 8 400 rad, 2 weeks of rest in middle of the treatment period. Scheme II : 200 rad once a day, 5 days a week, a total tumor dose of 6 400 rad, 2 weeks of rest in the middle of the treatment period. The results suggest an improved therapeutic ratio with Scheme I in comparison to Scheme II.

  14. Importance of dose-rate and cell proliferation in the evaluation of biological experimental results

    NASA Technical Reports Server (NTRS)

    Curtis, S. B.

    1994-01-01

    The nuclei of cells within the bodies of astronauts traveling on extended missions outside the geomagnetosphere will experience single traversals of particles with high Linear Energy Transfer (LET) (e.g., one iron ion per one hundred years, on average) superimposed on a background of tracks with low LET (approximately one proton every two to three days, and one helium ion per month). In addition, some cell populations within the body will be proliferating, thus possibly providing increasing numbers of cells with 'initiated' targets for subsequent radiation hits. These temporal characteristics are not generally reproduced in laboratory experimental protocols. Implications of the differences in the temporal patterns of radiation delivery between conventionally designed radiation biology experiments and the pattern to be experienced in space are examined and the importance of dose-rate and cell proliferation are pointed out in the context of radiation risk assessment on long mission in space.

  15. Importance of dose-rate and cell proliferation in the evaluation of biological experimental results

    NASA Technical Reports Server (NTRS)

    Curtis, S. B.

    1994-01-01

    The nuclei of cells within the bodies of astronauts traveling on extended missions outside the geomagnetosphere will experience single traversals of particles with high Linear Energy Transfer (LET) (e.g., one iron ion per one hundred years, on average) superimposed on a background of tracks with low LET (approximately one proton every two to three days, and one helium ion per month). In addition, some cell populations within the body will be proliferating, thus possibly providing increasing numbers of cells with 'initiated' targets for subsequent radiation hits. These temporal characteristics are not generally reproduced in laboratory experimental protocols. Implications of the differences in the temporal patterns of radiation delivery between conventionally designed radiation biology experiments and the pattern to be experienced in space are examined and the importance of dose-rate and cell proliferation are pointed out in the context of radiation risk assessment on long mission in space.

  16. Radiation Dose Survey for Common Computed Tomography Exams: 2013 British Columbia Results.

    PubMed

    Thakur, Yogesh; Bjarnason, Thorarin A; Baxter, Patricia; Griffith, Mitch; Eaton, Kirk

    2016-02-01

    In 2013 Health Canada conducted a national survey of computed tomography (CT) radiation usage. We analysed contributions from all 7 public health authorities in the province of British Columbia, which covered scanner age, number of slices, and common adult protocols (≥ 19 years: 70 ± 20 kg, head, chest, abdomen/pelvis, and trunk). Patient doses were recorded for common protocols. Diagnostic reference levels (DRLs) was calculated using scanner data with >10 patient doses recorded for each protocol. Data was analysed based on image reconstruction (filtered backprojection vs iterative reconstruction [IR] vs IR available but not in use). Provincial response was 92%, with 59 of 64 CT data used for analysis. The average scanner age was 5.5 years old, with 39% of scanners installed between 2008-2013; 78.5% of scanners were multislice (>64 slices), and 44% of scanners had IR available. Overall British Columbia DRLs were: head = 1305, chest = 529, abdomen/pelvis = 819, and trunk = 1225. DRLs were consistent with Health Canada recommendations and other Canadian published values, but above international standards. For sites with IR available, less than 50% used this technology routinely for head, chest and trunk exams. Overall, use of IR reduced radiation usage between 11%-32% compared to filtered backprojection, while sites using IR vs IR available used 30%/43% less radiation for head/chest exams (P < .05). No significant difference was observed for abdomen/pelvis exams (P = .385). With the fast pace of CT technical advancement, DRLs should reflect the technology used, instead of just globally applied to anatomical regions. Federal guidelines should be updated at a higher frequency to reflect new technology. In addition, new technologies must be utilised to optimize image quality vs radiation usage. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  17. The principal results of the International Immune Tolerance Study: a randomized dose comparison.

    PubMed

    Hay, Charles R M; DiMichele, Donna M

    2012-02-09

    The International Immune Tolerance Study was a multicenter, prospective, randomized comparison of high-dose (HD; 200 IU/kg/d) and low-dose (LD; 50 IU/kg 3 times/week) factor VIII regimens in 115 "good-risk," severe high-titer inhibitor hemophilia A subjects. Sixty-six of 115 subjects reached the defined study end points: success, n = 46 (69.7%); partial response, n = 3 (4.5%); and failure, n = 17 (25.8%). Successes did not differ between treatment arms (24 of 58 LD vs 22/57 HD, P = .909). The times taken to achieve a negative titer (P = .027), a normal recovery (P = .002), and tolerance (P = .116, nonsignificant) were shorter with the HD immune tolerance induction (ITI). Peak historical (P = .026) and on-ITI (P = .002) titers were correlated inversely with success, but only peak titer on ITI predicted outcome in a multivariate analysis (P = .002). LD subjects bled more often (odds ratio, 2.2; P = .0019). The early bleed rate/month was 0.62 (LD) and 0.28 (HD; P = .000 24), decreasing by 90% once negative titers were achieved. Bleeding was absent in 8 of 58 LD versus 21 of 57 HD subjects (P = .0085). One hundred twenty-four central catheter infections were reported in 41 subjects (19 LD); infection frequency did not differ between the treatment arms. Neither bleeding nor infection influenced outcome. Although it was stopped early for futility and safety considerations, this trial contributed valuable data toward evidence-based ITI practice.

  18. Safety and immunogenicity of the PRAME cancer immunotherapeutic in metastatic melanoma: results of a phase I dose escalation study

    PubMed Central

    Gutzmer, R; Rivoltini, L; Levchenko, E; Testori, A; Utikal, J; Ascierto, P A; Demidov, L; Grob, J J; Ridolfi, R; Schadendorf, D; Queirolo, P; Santoro, A; Loquai, C; Dreno, B; Hauschild, A; Schultz, E; Lesimple, T P; Vanhoutte, N; Salaun, B; Gillet, M; Jarnjak, S; De Sousa Alves, P M; Louahed, J; Brichard, V G; Lehmann, F F

    2016-01-01

    Purpose The PRAME tumour antigen is expressed in several tumour types but in few normal adult tissues. A dose-escalation phase I/II study (NCT01149343) assessed the safety, immunogenicity and clinical activity of the PRAME immunotherapeutic (recombinant PRAME protein (recPRAME) with the AS15 immunostimulant) in patients with advanced melanoma. Here, we report the phase I dose-escalation study segment. Patients and methods Patients with stage IV PRAME-positive melanoma were enrolled to 3 consecutive cohorts to receive up to 24 intramuscular injections of the PRAME immunotherapeutic. The RecPRAME dose was 20, 100 or 500 µg in cohorts 1, 2 and 3, respectively, with a fixed dose of AS15. Adverse events (AEs), including predefined dose-limiting toxicity (DLT) and the anti-PRAME humoral response (ELISA), were coprimary end points. Cellular immune responses were evaluated using in vitro assays. Results 66 patients were treated (20, 24 and 22 in the respective cohorts). AEs considered by the investigator to be causally related were mostly grade 1 or 2 injection site symptoms, fatigue, chills, fever and headache. Two DLTs (grade 3 brain oedema and proteinuria) were recorded in two patients in two cohorts (cohorts 2 and 3). All patients had detectable anti-PRAME antibodies after four immunisations. Percentages of patients with predefined PRAME-specific-CD4+T-cell responses after four immunisations were similar in each cohort. No CD8+ T-cell responses were detected. Conclusions The PRAME immunotherapeutic had an acceptable safety profile and induced similar anti-PRAME-specific humoral and cellular immune responses in all cohorts. As per protocol, the phase II study segment was initiated to further evaluate the 500 µg PRAME immunotherapeutic dose. Trial registration number NCT01149343, Results. PMID:27843625

  19. SRS 2010 Vegetation Inventory GeoStatistical Mapping Results for Custom Reaction Intensity and Total Dead Fuels.

    SciTech Connect

    Edwards, Lloyd A.; Paresol, Bernard

    2014-09-01

    This report of the geostatistical analysis results of the fire fuels response variables, custom reaction intensity and total dead fuels is but a part of an SRS 2010 vegetation inventory project. For detailed description of project, theory and background including sample design, methods, and results please refer to USDA Forest Service Savannah River Site internal report “SRS 2010 Vegetation Inventory GeoStatistical Mapping Report”, (Edwards & Parresol 2013).

  20. Statistical analyses of fracture toughness results for two irradiated high-copper welds

    SciTech Connect

    Nanstad, R.K.; McCabe, D.E.; Haggag, F.M.; Bowman, K.O.; Downing, D.J.

    1990-01-01

    The objectives of the Heavy-Section Steel Irradiation Program Fifth Irradiation Series were to determine the effects of neutron irradiation on the transition temperature shift and the shape of the K{sub Ic} curve described in Sect. 6 of the ASME Boiler and Pressure Vessel Code. Two submerged-arc welds with copper contents of 0.23 and 0.31% were commercially fabricated in 215-mm-thick plates. Charpy V-notch (CVN) impact, tensile, drop-weight, and compact specimens up to 203.2 mm thick (1T, 2T, 4T, 6T, and 8T C(T)) were tested to provide a large data base for unirradiated material. Similar specimens with compacts up to 4T were irradiated at about 288{degrees}C to a mean fluence of about 1.5 {times} 10{sup 19} neutrons/cm{sup 2} (>1 MeV) in the Oak Ridge Research Reactor. Both linear-elastic and elastic-plastic fracture mechanics methods were used to analyze all cleavage fracture results and local cleavage instabilities (pop-ins). Evaluation of the results showed that the cleavage fracture toughness values determined at initial pop-ins fall within the same scatter band as the values from failed specimens; thus, they were included in the data base for analysis (all data are designated K{sub Jc}).

  1. The Solid Rocket Motor Slag Population: Results of a Radar-based Regressive Statistical Evaluation

    NASA Technical Reports Server (NTRS)

    Horstman, Matthew F.; Xu, Yu-Lin

    2008-01-01

    Solid rocket motor (SRM) slag has been identified as a significant source of man-made orbital debris. The propensity of SRMs to generate particles of 100 m and larger has caused concern regarding their contribution to the debris environment. Radar observation, rather than in-situ gathered evidence, is currently the only measurable source for the NASA/ODPO model of the on-orbit slag population. This simulated model includes the time evolution of the resultant orbital populations using a historical database of SRM launches, propellant masses, and estimated locations and times of tail-off. However, due to the small amount of observational evidence, there can be no direct comparison to check the validity of this model. Rather than using the assumed population developed from purely historical and physical assumptions, a regressional approach was used which utilized the populations observed by the Haystack radar from 1996 to present. The estimated trajectories from the historical model of slag sources, and the corresponding plausible detections by the Haystack radar, were identified. Comparisons with observational data from the ensuing years were made, and the SRM model was altered with respect to size and mass production of slag particles to reflect the historical data obtained. The result is a model SRM population that fits within the bounds of the observed environment.

  2. The Solid Rocket Motor Slag Population: Results of a Radar-based Regressive Statistical Evaluation

    NASA Technical Reports Server (NTRS)

    Horstman, Matthew F.; Xu, Yu-Lin

    2008-01-01

    Solid rocket motor (SRM) slag has been identified as a significant source of man-made orbital debris. The propensity of SRMs to generate particles of 100 m and larger has caused concern regarding their contribution to the debris environment. Radar observation, rather than in-situ gathered evidence, is currently the only measurable source for the NASA/ODPO model of the on-orbit slag population. This simulated model includes the time evolution of the resultant orbital populations using a historical database of SRM launches, propellant masses, and estimated locations and times of tail-off. However, due to the small amount of observational evidence, there can be no direct comparison to check the validity of this model. Rather than using the assumed population developed from purely historical and physical assumptions, a regressional approach was used which utilized the populations observed by the Haystack radar from 1996 to present. The estimated trajectories from the historical model of slag sources, and the corresponding plausible detections by the Haystack radar, were identified. Comparisons with observational data from the ensuing years were made, and the SRM model was altered with respect to size and mass production of slag particles to reflect the historical data obtained. The result is a model SRM population that fits within the bounds of the observed environment.

  3. Statistical analysis of sound transmission results obtained on the New Jersey continental shelf.

    PubMed

    Dediu, Simona M; Siegmann, William L; Carey, William M

    2007-08-01

    Experiments have been conducted near the site of AMCOR Borehole 6010 on the New Jersey Shelf to evaluate propagation predictability in sandy shallow-water environments. The influence of a nonlinear frequency dependence of the sediment volume attenuation in the uppermost sediment layer at this location is examined. Previously it was determined that a frequency power-law exponent of 1.5 was required for the best modeling of experimental results over the band 50-1000 Hz. The approach here references the attenuation to an accepted value at 1 kHz and makes extensive comparisons between measurements and calculations, to determine a power-law exponent of 1.85+/-0.15.

  4. Statistical results describing the bandwidth and coherence coefficient of whistler mode waves using THEMIS waveform data

    NASA Astrophysics Data System (ADS)

    Gao, X.; Li, W.; Thorne, R. M.; Bortnik, J.; Angelopoulos, V.; Lu, Q.; Tao, X.; Wang, S.

    2014-11-01

    The bandwidths and coherence coefficients of lower band whistler mode waves are analyzed using Time History of Events and Macroscale Interactions during Substorms (THEMIS) waveform data for rising tones, falling tones, and hiss-like emissions separately. We also evaluate their dependences on the spatial location, electron density, the ratio of plasma frequency to local electron gyrofrequency (fpe/fce), and the wave amplitude. Our results show that the bandwidth normalized by the local electron gyrofrequency (fce) of rising and falling tones is very narrow (~0.01 fce), smaller than that of the hiss-like emissions (~0.025 fce). Meanwhile, the normalized bandwidth of discrete emissions gradually decreases with increasing wave amplitude, whereas that of hiss-like emissions increases slowly. The coherence coefficient of rising and falling tones is extremely large (~1), while the coherence coefficient of hiss-like emissions is smaller but is still larger than 0.5. For all categories of whistler mode waves, the normalized bandwidth increases at larger L shells. Furthermore, the normalized bandwidth is positively correlated with local fpe/fce but is inversely correlated with the electron density. Interactions between radiation belt electrons and whistler mode waves have been widely described by quasi-linear diffusion theory. Our results suggest that although quasi-linear theory is not entirely applicable for modeling electron interactions with rising and falling tones due to their narrow bandwidth and high coherence coefficient, it is suitable to treat wave-particle interactions between electrons and low-amplitude hiss-like emissions. Moreover, the correlations between the normalized bandwidth of chorus waves (especially the discrete emissions) and other parameters may provide insights for the generation mechanism of chorus waves.

  5. Statistical mechanical treatment of the structural hydration of biological macromolecules: Results for B-DNA

    NASA Astrophysics Data System (ADS)

    Hummer, Gerhard; Soumpasis, Dikeos Mario

    1994-12-01

    We constructed an efficient and accurate computational tool based on the potentials-of-mean-force approach for computing the detailed hydrophilic hydration of complex molecular structures in aqueous environments. Using the pair and triplet correlation functions database previously obtained from computer simulations of the simple point charge model of water, we computed the detailed structural organization of water around two B-DNA molecules with sequences d(AATT)3.d(AATT)3 and d(CCGG)3.d(CCGG)3, and canonical structure. [A, T, C, and G denote adenine, thymine, cytosine, and guanine, respectively, and d(...) denotes the deoxyribose in the sugar-phosphate backbone.] The results obtained are in agreement with the experimental observations. A.T base-pair stretches are found to support the marked minor-groove ``spines of hydration'' observed in x-ray crystal structures. The hydrophilic hydration of the minor groove of the molecule d(CCGG)3.d(CCGG)3 exhibits a double ribbon of high water density, which is also in agreement with x-ray crystallography observations of C.G base-pair regions. The major grooves, on the other hand, do not show a comparably strong localization of water molecules. The quantitative results are compared with a computer simulation study of Forester et al. [Mol. Phys. 72, 643 (1991)]. We find good agreement for the hydration of the -NH2 groups, the cylindrically averaged water density distributions, and the overall hydration number. The agreement is less satisfactory for the phosphate groups. However, by refining the treatment of the anionic oxygens on the phosphate groups, almost full quantitative agreement is achieved.

  6. Dose Reduction of Caspofungin in Intensive Care Unit Patients with Child Pugh B Will Result in Suboptimal Exposure.

    PubMed

    Martial, Lisa C; Brüggemann, Roger J M; Schouten, Jeroen A; van Leeuwen, Henk J; van Zanten, Arthur R; de Lange, Dylan W; Muilwijk, Eline W; Verweij, Paul E; Burger, David M; Aarnoutse, Rob E; Pickkers, Peter; Dorlo, Thomas P C

    2016-06-01

    Caspofungin is an echinocandin antifungal agent used as first-line therapy for the treatment of invasive candidiasis. The maintenance dose is adapted to body weight (BW) or liver function (Child-Pugh score B or C). We aimed to study the pharmacokinetics of caspofungin and assess pharmacokinetic target attainment for various dosing strategies. Caspofungin pharmacokinetic data from 21 intensive care unit (ICU) patients was available. A population pharmacokinetic model was developed. Various dosing regimens (loading dose/maintenance dose) were simulated: licensed regimens (I) 70/50 mg (for BW <80 kg) or 70/70 mg (for BW >80 kg); and (II) 70/35 mg (for Child-Pugh score B); and adapted regimens (III) 100/50 mg (for Child-Pugh score B); (IV) 100/70 mg; and (V) 100/100 mg. Target attainment based on a preclinical pharmacokinetic target for Candida albicans was assessed for relevant minimal inhibitory concentrations (MICs). A two-compartment model best fitted the data. Clearance was 0.55 L/h and the apparent volumes of distribution in the central and peripheral compartments were 8.9 and 5.0 L, respectively. The median area under the plasma concentration-time curve from time zero to 24 h on day 14 for regimens I-V were 105, 65, 93, 130, and 186 mg·h/L, respectively. Pharmacokinetic target attainment was 100 % (MIC 0.03 µg/mL) irrespective of dosing regimen but decreased to (I) 47 %, (II) 14 %, (III) 36 %, (IV) 69 %, and (V) 94 % for MIC 0.125 µg/mL. The caspofungin maintenance dose should not be reduced in non-cirrhotic ICU patients based on the Child-Pugh score if this classification is driven by hypoalbuminemia as it results in significantly lower exposure. A higher maintenance dose of 70 mg in ICU patients results in target attainment of >90 % of the ICU patients with species with an MIC of up to 0.125 µg/mL.

  7. [Focal dose escalation in the treatment of prostate cancer : Long-term results of HDR brachytherapy].

    PubMed

    Cordes, J; Broschk, J; Sommerauer, M; Jocham, D; Merseburger, A S; Melchert, C; Kovács, G

    2017-02-01

    We prospectively examined the effect and the safety of intensity-modulated HDR brachytherapy (IMBT) with focal dose escalation. A total of 139 patients undergoing primary therapy for prostate cancer and 11 patients with recurrence were included. Data analysis focused on the following factors: date of primary diagnosis, Gleason score, initial prostate-specific antigen (PSA) value, PSA nadir, volume of the prostate in the transrectal ultrasound, biopsy of the prostate gland, androgen deprivation, chemotherapy, uroflowmetry, pre- and postoperative post-void residual urine (PVR), number of the needles in the prostate lobes and analysis of follow-up data. In the primary therapy group, 87.6 % of the patients had a PSA of 0-4 ng/ml at the time of follow-up, while in the recurrence group 81.8 % of patients were within this range. Overall, 55.8 % of patients in the primary group had a PSA nadir under 0.1 ng/ml, 37.2 % under 1 ng/ml, 5.8 % under 5 ng/ml and 1.2 % (1 patient) over 5 ng/ml. In the recurrence group, 100 % had a PSA nadir under 0.1 ng/dl. Fifty patients of the primary group reported grade 1 toxicity (Common Toxicity Criteria): 29 localized to the bladder and 21 to the rectum. Seventeen patients had grade 2 toxicity of the bladder and 1 patient had grade 3 toxicity of the bladder. Finally there was one grade 4 toxicity due to perforation of the sigmoid colon. In the recurrence group, 3 patients with grade 1 toxicity were observed (2 bladder and 1 bowl). Also 3 patients had grade 2 toxicity of the bladder, 1 patient had a grade 3 bladder toxicity and 1 patient had grade 4 toxicity due to bowl fistula. There were no grade 5 toxicities. The modifications of the "Kiel method" with focal dose escalation was proven as effective in locally advanced prostate carcinoma and in local recurrences of the disease with low level toxicity.

  8. Statistical results from 10 years of Cassini Langmuir probe plasma measurements

    NASA Astrophysics Data System (ADS)

    Holmberg, M.; Shebanits, O.; Wahlund, J. E.; Morooka, M.; Andre, N.

    2016-12-01

    We use a new analysis method to obtain 10 years of Cassini RPWS Langmuir probe (LP) measurements to study the structure and dynamics of the inner plasma disk of Saturn. The LP plasma density measurements show good agreement with electron densities derived from the RPWS electric field power spectra and confirms and/or improves a number of previous findings about the structure of the plasma disk. E.g., the Enceladus plume is detected as a localised density maximum at the orbit of Enceladus, but the peak density of the inner plasma disk, excluding Enceladus plume passages, is located closer to 4.7 Rs. No density peaks are recorded at the orbits of the moons Mimas, Tethys, Dione, and Rhea. We confirm the previously detected plasma density dayside/nightside asymmetry, which is likely due to a particle drift in the dusk to dawn direction. Presented is also the LP result on the seasonal dependence of the plasma disk within Enceladus' orbit.

  9. Unrealistic statistics: how average constitutive coefficients can produce non-physical results.

    PubMed

    Robertson, Daniel; Cook, Douglas

    2014-12-01

    The coefficients of constitutive models are frequently averaged in order to concisely summarize the complex, nonlinear, material properties of biomedical materials. However, when dealing with nonlinear systems, average inputs (e.g. average constitutive coefficients) often fail to generate average behavior. This raises an important issue because average nonlinear constitutive coefficients of biomedical materials are commonly reported in the literature. This paper provides examples which demonstrate that average constitutive coefficients applied to nonlinear constitutive laws in the field of biomedical material characterization can fail to produce average stress-strain responses and in some cases produce non-physical responses. Results are presented from a literature survey which indicates that approximately 90% of tissue measurement studies that employ a nonlinear constitutive model report average nonlinear constitutive coefficients. We suggest that reviewers and editors of future measurement studies discourage the reporting of average nonlinear constitutive coefficients. Reporting of individual coefficient sets for each test sample should be considered and discussed as designation for a "best practice" in the field of biomedical material characterization.

  10. Immunogenicity of quadrivalent HPV vaccine among girls 11 to 13 Years of age vaccinated using alternative dosing schedules: results 29 to 32 months after third dose.

    PubMed

    Lamontagne, D Scott; Thiem, Vu Dinh; Huong, Vu Minh; Tang, Yuxiao; Neuzil, Kathleen M

    2013-10-15

     Immune response to quadrivalent human papillomavirus (HPV) vaccine delivered at 0, 2, and 6 months in young adolescent females plateaus around 24 months after immunization. Antibody levels >24 months postvaccination using extended dosing schedules is unknown.  We conducted a follow-up immunogenicity study of adolescent girls in Vietnam who participated in a noninferiority trial to investigate whether immune responses using 3 alternative dosing schedules (0, 3, 9 months; 0, 6, 12 months; or 0, 12, 24 months) are noninferior to the standard schedule at >2 years after immunization.  Quadrivalent HPV vaccine immunogenicity delivered on 3 alternative dosing schedules was noninferior for types 6, 11, 16, and 18 at 32 months post-dose 3 compared to the standard schedule. Pre-dose 3 antibody levels for the 0, 12, 24 month schedule were similar to those measured 32-months post-dose 3.  We found similar antibody concentrations ≥29 months after 3 doses of HPV vaccine regardless of dose-timing, and extended schedules do not produce inferior immune responses. Our findings also suggested that 2 doses of HPV vaccine delivered at 0 and 12 months might afford similar protection. Evidence supporting dosing flexibility could be important for national HPV vaccination policies.

  11. The Solid Rocket Motor Slag Population: Results of a Radar-Based Regressive Statistical Evaluation

    NASA Astrophysics Data System (ADS)

    Horstman, Matthew

    estimated locations and times of tail-off to produce and propagate the SRM debris clouds. Comparisons with radar data from the ensuing years were made, and the SRM model was altered with respect to size and mass production of slag particles to reflect the populations estimated from the data. The result is a model SRM population that fits within the bounds of the observed environment and estimates of the production and contribution of SRM debris to the environment.

  12. The Solid Rocket Motor Slag Population: Results of a Radar-Based Regressive Statistical Evaluation

    NASA Technical Reports Server (NTRS)

    Horstman, Matthew F.; Xu, Yu-Lin

    2008-01-01

    estimated locations and times of tailoff to produce and propagate the SRM debris clouds. Comparisons with radar data from the ensuing years were made, and the SRM model was altered with respect to size and mass production of slag particles to reflect the populations estimated from the data. The result is a model SRM population that fits within the bounds of the observed environment and estimates of the production and contribution of SRM debris to the environment.

  13. The Solid Rocket Motor Slag Population: Results of a Radar-Based Regressive Statistical Evaluation

    NASA Technical Reports Server (NTRS)

    Horstman, Matthew F.; Xu, Yu-Lin

    2008-01-01

    estimated locations and times of tailoff to produce and propagate the SRM debris clouds. Comparisons with radar data from the ensuing years were made, and the SRM model was altered with respect to size and mass production of slag particles to reflect the populations estimated from the data. The result is a model SRM population that fits within the bounds of the observed environment and estimates of the production and contribution of SRM debris to the environment.

  14. Results of a programme to improve house staff use of metered dose inhalers and spacers.

    PubMed

    Lee-Wong, M; Mayo, P H

    2003-04-01

    Metered dose inhalers (MDIs) and spacers are used widely in the treatment of asthma. Medical personnel who are responsible for training patients must themselves be proficient with the devices. The proficiency of a group of new medical interns with use of MDI and spacer devices was determined, and improvement in their use of these devices was sought. Fifty six medical interns tested at the start of their first house staff training year. The ability of medical interns to use MDIs and spacers was assessed using a visual scoring system before and after a large group lecture emphasising proper device use and once again after an intensive one-on-one training session with an attending physician. Initially, only 5% used an MDI perfectly. This improved to 13% after a lecture and demonstration, and 73% after an intensive one-on-one session. Almost no new interns could use a collapsible or tube spacer properly initially. This improved to 15% and 29% respectively after a lecture. After one-on-one training, correct technique was increased to 69% for collapsible spacer and 95% for the tube spacer. Analysis of individual steps of MDI use showed that interns had particular difficulty in coordinating actuation with inhalation. The tube spacer appeared easiest to learn. Incoming medical house staff have limited ability to use MDI with and without spacers. A large group lecture is relatively ineffective when compared with a one-on-one training session in training with these devices.

  15. Is received dose from ingested soil independent of soil PAH concentrations?-Animal model results.

    PubMed

    Peters, Rachel E; James, Kyle; Cave, Mark; Wickstrom, Mark; Siciliano, Steven D

    2016-09-01

    Polycyclic aromatic hydrocarbon (PAH) bioavailability from ingested soils will vary between soils; however, the nature of this variation is not well characterized. A juvenile swine model was used to link external exposure to internal benzo[a]pyrene (BaP) and anthracene exposure following oral PAH ingestion of 27 different impacted site soils, soots, or spiked artificial soils. Internal exposure of BaP and anthracene, represented by area under the plasma-time curve, did not relate to soil concentration in impacted site soils, but did relate in spiked artificial soil. Point of departure modeling identified soil PAH concentrations greater than 1900 mg kg(-1) as the point where area under the curve becomes proportional to external dose. A BaP internal exposure below 1900 mg kg(-1) had an upper 95% confidence interval estimate of 33% of external exposure. Weak relationships between soil:simulated gastrointestinal fluid PAH partitioning and area under the curve values suggest that differences in internal PAH exposure between soils may not be dominated by differences in PAH partitioning. The data seem to best support exposure assessment assuming constant internal PAH exposure below soil concentrations of 1900 mg kg(-1) . However, because constant internal exposure would challenge several existing paradigms, a bioavailability estimate of 33% of the external exposure is suggested as a likely workable solution. Environ Toxicol Chem 2016;35:2261-2269. © 2016 SETAC.

  16. Results of animal studies suggest a nonlinear dose-response relationship for benzene effects

    SciTech Connect

    Parodi, S.; Taningher, M. ); Lutz, W.K. ); Colacci, A.; Mazzullo, M.; Grilli, S. )

    1989-07-01

    Considering the very large industrial usage of benzene, studies in risk assessment aimed at the evaluation of carcinogenic risk at low levels of exposure are important. Animal data can offer indications about what could happen in humans and provide more diverse information than epidemiological data with respect to dose-response consideration. The authors have considered experiments investigating metabolism, short-term genotoxicity tests, DNA adduct formation, and carcinogenicity long-term tests. According to the different experiments, a saturation of benzene metabolism and benzene effects in terms of genotoxicity seems evident above 30 to 100 ppm. Below 30 to 60 ppm the initiating effect of benzene seems to be linear for a large interval of dosages, at least judging from DNA adduct formation. Potential lack of a promoting effect of benzene (below 10 ppm) could generate a sublinear response at nontoxic levels of exposure. This possibility was suggested by epidemiological data in humans and is not confirmed or excluded by their observations with animals.

  17. Statistical results from the Virginia Tech propagation experiment using the Olympus 12, 20, and 30 GHz satellite beacons

    NASA Technical Reports Server (NTRS)

    Stutzman, Warren L.; Safaai-Jazi, A.; Pratt, Timothy; Nelson, B.; Laster, J.; Ajaz, H.

    1993-01-01

    Virginia Tech has performed a comprehensive propagation experiment using the Olympus satellite beacons at 12.5, 19.77, and 29.66 GHz (which we refer to as 12, 20, and 30 GHz). Four receive terminals were designed and constructed, one terminal at each frequency plus a portable one with 20 and 30 GHz receivers for microscale and scintillation studies. Total power radiometers were included in each terminal in order to set the clear air reference level for each beacon and also to predict path attenuation. More details on the equipment and the experiment design are found elsewhere. Statistical results for one year of data collection were analyzed. In addition, the following studies were performed: a microdiversity experiment in which two closely spaced 20 GHz receivers were used; a comparison of total power and Dicke switched radiometer measurements, frequency scaling of scintillations, and adaptive power control algorithm development. Statistical results are reported.

  18. 42 CFR 82.27 - How can claimants obtain reviews of their NIOSH dose reconstruction results by NIOSH?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... radiation exposures of DOE or AWE employees that could substantially increase the level of radiation doses... the level of radiation doses estimated in the completed dose reconstructions. (c) When NIOSH...

  19. 42 CFR 82.27 - How can claimants obtain reviews of their NIOSH dose reconstruction results by NIOSH?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... radiation exposures of DOE or AWE employees that could substantially increase the level of radiation doses... the level of radiation doses estimated in the completed dose reconstructions. (c) When NIOSH...

  20. 42 CFR 82.27 - How can claimants obtain reviews of their NIOSH dose reconstruction results by NIOSH?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... radiation exposures of DOE or AWE employees that could substantially increase the level of radiation doses... the level of radiation doses estimated in the completed dose reconstructions. (c) When NIOSH...

  1. Variability of low-density lipoprotein cholesterol response with different doses of atorvastatin, rosuvastatin, and simvastatin: results from VOYAGER.

    PubMed

    Karlson, Björn W; Wiklund, Olov; Palmer, Michael K; Nicholls, Stephen J; Lundman, Pia; Barter, Philip J

    2016-10-01

    Patient response to statin treatment is individual and varied. As a consequence, when using a specific-dose approach, as recommended in the 2013 American College of Cardiology/American Heart Association guideline, there will be a range of reductions in the concentration of low-density lipoprotein cholesterol (LDL-C). The aim of this study was to use individual patient data from the VOYAGER meta-analysis to determine the extent of the variability in LDL-C reduction in response to treatment across the recommended doses of different statins. The percentage change from baseline in LDL-C was calculated using individual subject data collected from 32 258 patients treated with atorvastatin 10-80 mg, rosuvastatin 5-40 mg, or simvastatin 10-80 mg. The percentage change in LDL-C for each patient was then used to generate waterfall plots that demonstrated the extent of the variability in response to treatment at all doses of the three statins. The standard deviation of LDL-C reduction for all statins and doses ranged from 12.8 to 17.9%. The percentage of patients experiencing a suboptimal response (<30% reduction in LDL-C) ranged from 5.3 to 53.3%. These results indicate that there is considerable individual variation in the LDL-C reduction at all doses of simvastatin, atorvastatin, and rosuvastatin. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  2. Latin American dose survey results in mammography studies under IAEA programme: radiological protection of patients in medical exposures (TSA3).

    PubMed

    Mora, Patricia; Blanco, Susana; Khoury, Helen; Leyton, Fernando; Cárdenas, Juan; Defaz, María Yolanda; Garay, Fernando; Telón, Flaviano; Aguilar, Juan Garcia; Roas, Norma; Gamarra, Mirtha; Blanco, Daniel; Quintero, Ana Rosa; Nader, Alejandro

    2015-03-01

    Latin American countries (Argentina, Brazil, Chile, Costa Rica, Cuba, Ecuador, El Salvador, Guatemala, Mexico, Nicaragua, Paraguay, Uruguay and Venezuela) working under the International Atomic Energy Agency (IAEA) Technical Cooperation Programme: TSA3 Radiological Protection of Patients in Medical Exposures have joined efforts in the optimisation of radiation protection in mammography practice. Through surveys of patient doses, the region has a unique database of diagnostic reference levels for analogue and digital equipment that will direct future optimisation activities towards the early detection of breast cancer among asymptomatic women. During RLA9/057 (2007-09) 24 institutions participated with analogue equipment in a dose survey. Regional training on methodology and measurement equipment was addressed in May 2007. The mean glandular dose (DG) was estimated using the incident kerma in air and relevant conversion coefficients for both projections craneo caudal and mediolateral oblique (CC and MLO). For Phase 2, RLA9/067 (2010-11), it was decided to include also digital systems in order to see their impact in future dose optimisation activities. Any new country that joined the project received training in the activities through IAEA expert missions. Twenty-nine new institutions participated (9 analogue and 20 digital equipment). A total of 2262 patient doses were collected during this study and from them D(G) (mGy) for both projections were estimated for each institution and country. Regional results (75 percentile in mGy) show for CC and MLO views, respectively: RLA9/057 (analogue) 2.63 and 3.17; RLA/067: 2.57 and 3.15 (analogue) and 2.69 and 2.90 (digital). Regarding only digital equipment for CC and MLO, respectively, computed radiography systems showed 2.59 and 2.78 and direct digital radiography (DDR) systems 2.78 and 3.04. Based on the IAEA Basic Safety Standard (BSS) reference dose (3 mGy), it can be observed that there is enough room to start

  3. A Consumer's Guide to Benchmark Dose Models: Results of U.S. EPA Testing of 14 Dichotomous, 8 Continuous, and 6 Developmental Models (Presentation)

    EPA Science Inventory

    Benchmark dose risk assessment software (BMDS) was designed by EPA to generate dose-response curves and facilitate the analysis, interpretation and synthesis of toxicological data. Partial results of QA/QC testing of the EPA benchmark dose software (BMDS) are presented. BMDS pr...

  4. A Consumer's Guide to Benchmark Dose Models: Results of U.S. EPA Testing of 14 Dichotomous, 8 Continuous, and 6 Developmental Models (Presentation)

    EPA Science Inventory

    Benchmark dose risk assessment software (BMDS) was designed by EPA to generate dose-response curves and facilitate the analysis, interpretation and synthesis of toxicological data. Partial results of QA/QC testing of the EPA benchmark dose software (BMDS) are presented. BMDS pr...

  5. 42 CFR 82.4 - How Will DOL Use the Results of the NIOSH Dose Reconstructions?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... reconstruction results together with information on cancer diagnosis and other personal information provided to... probability that the cancer of the covered employee was caused by radiation exposure at a covered facility of...

  6. 42 CFR 82.4 - How Will DOL Use the Results of the NIOSH Dose Reconstructions?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... reconstruction results together with information on cancer diagnosis and other personal information provided to... probability that the cancer of the covered employee was caused by radiation exposure at a covered facility of...

  7. 42 CFR 82.4 - How Will DOL Use the Results of the NIOSH Dose Reconstructions?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... reconstruction results together with information on cancer diagnosis and other personal information provided to... probability that the cancer of the covered employee was caused by radiation exposure at a covered facility of...

  8. 42 CFR 82.4 - How Will DOL Use the Results of the NIOSH Dose Reconstructions?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... reconstruction results together with information on cancer diagnosis and other personal information provided to... probability that the cancer of the covered employee was caused by radiation exposure at a covered facility of...

  9. Very Low Dose Fetal Exposure to Chernobyl Contamination Resulted in Increases in Infant Leukemia in Europe and Raises Questions about Current Radiation Risk Models

    PubMed Central

    Busby, Christopher C.

    2009-01-01

    Following contamination from the Chernobyl accident in April 1986 excess infant leukemia (0–1 y) was reported from five different countries, Scotland, Greece, Germany, Belarus and Wales and Scotland combined. The cumulative absorbed doses to the fetus, as conventionally assessed, varied from 0.02 mSv in the UK through 0.06 mSv in Germany, 0.2 mSv in Greece and 2 mSv in Belarus, where it was highest. Nevertheless, the effect was real and given the specificity of the cohort raised questions about the safety of applying the current radiation risk model of the International Commission on Radiological Protection (ICRP) to these internal exposures, a matter which was discussed in 2000 by Busby and Cato [7,8] and also in the reports of the UK Committee examining Radiation Risk from Internal Emitters. Data on infant leukemia in the United Kingdom, chosen on the basis of the cohorts defined by the study of Greece were supplied by the UK Childhood Cancer Research Group. This has enabled a study of leukemia in the combined infant population of 15,466,845 born in the UK, Greece, and Germany between 1980 and 1990. Results show a statistically significant excess risk RR = 1.43 (95% CI 1.13 < RR < 1.80 (2-tailed); p = 0.0025) in those born during the defined peak exposure period of 01/07/86 to 31/12/87 compared with those born between 01/01/80 and 31/12/85 and 01/01/88 and 31/12/90. The excess risks in individual countries do not increase monotonically with the conventionally calculated doses, the relation being biphasic, increasing sharply at low doses and falling at high doses. This result is discussed in relation to fetal/cell death at higher doses and also to induction of DNA repair. Since the cohort is chosen specifically on the basis of exposure to internal radionuclides, the result can be expressed as evidence for a significant error in the conventional modeling for such internal fetal exposures. PMID:20049249

  10. Evaluating the statistical conclusion validity of weighted mean results in meta-analysis by analysing funnel graph diagrams.

    PubMed

    Elvik, R

    1998-03-01

    The validity of weighted mean results estimated in meta-analysis has been criticized. This paper presents a set of simple statistical and graphical techniques that can be used in meta-analysis to evaluate common points of criticism. The graphical techniques are based on funnel graph diagrams. Problems and techniques for dealing with them that are discussed include: (1) the so-called 'apples and oranges' problem, stating that mean results in meta-analysis tend to gloss over important differences that should be highlighted. A test of the homogeneity of results is described for testing the presence of this problem. If results are highly heterogeneous, a random effects model of meta-analysis is more appropriate than the fixed effects model of analysis. (2) The possible presence of skewness in a sample of results. This can be tested by comparing the mode, median and mean of the results in the sample. (3) The possible presence of more than one mode in a sample of results. This can be tested by forming a frequency distribution of the results and examining the shape of this distribution. (4) The sensitivity of the mean to the possible presence of atypical results (outliers) can be tested by comparing the overall mean to the mean of all results except the one suspected of being atypical. (5) The possible presence of publication bias can be tested by visual inspection of funnel graph diagrams in which data points have been sorted according to statistical significance and direction of effect. (6) The possibility of underestimating the standard error of the mean in meta-analyses by using multiple, correlated results from the same study as the unit of analysis can be addressed by using the jack-knife technique for estimating the uncertainty of the mean. Brief examples, taken from road safety research, are given of all these techniques.

  11. Low dose cadmium poisoning results in sustained ERK phosphorylation and caspase activation

    SciTech Connect

    Martin, Patrick . E-mail: pmartin@unice.fr; Poggi, Marie Christine . E-mail: poggi@unice.fr; Chambard, Jean Claude . E-mail: chambard@unice.fr; Boulukos, Kim E. . E-mail: boulukos@unice.fr; Pognonec, Philippe . E-mail: pognonec@unice.fr

    2006-11-24

    Cadmium poisoning has been known to result in a wide variety of cellular responses, including oxidative stress and kinase activation. It has been reported that ERK is activated following acute cadmium exposure, and this response is commonly seen as a classical ERK survival mechanism. Here, we analyzed different cell types for their responses to low concentrations of cadmium poisoning. We found that there is an association between cell susceptibility to cadmium toxicity and ERK activation. This activation is atypical, since it consists of a sustained ERK phosphorylation, that lasts up to 6 days post stimulation. This activation is associated with the appearance of cleaved caspases 8 and 3, processed PARP, and irreversible damage. Pharmacological inhibition of ERK phosphorylation results in the ability of cells to resist cadmium poisoning. Our data indicate that low cadmium concentrations result in an unconventional ERK sustained phosphorylation, which in turn leads to death signaling.

  12. Comparison of dose estimates using the buildup-factor method and a Baryon transport code (BRYNTRN) with Monte Carlo results

    NASA Technical Reports Server (NTRS)

    Shinn, Judy L.; Wilson, John W.; Nealy, John E.; Cucinotta, Francis A.

    1990-01-01

    Continuing efforts toward validating the buildup factor method and the BRYNTRN code, which use the deterministic approach in solving radiation transport problems and are the candidate engineering tools in space radiation shielding analyses, are presented. A simplified theory of proton buildup factors assuming no neutron coupling is derived to verify a previously chosen form for parameterizing the dose conversion factor that includes the secondary particle buildup effect. Estimates of dose in tissue made by the two deterministic approaches and the Monte Carlo method are intercompared for cases with various thicknesses of shields and various types of proton spectra. The results are found to be in reasonable agreement but with some overestimation by the buildup factor method when the effect of neutron production in the shield is significant. Future improvement to include neutron coupling in the buildup factor theory is suggested to alleviate this shortcoming. Impressive agreement for individual components of doses, such as those from the secondaries and heavy particle recoils, are obtained between BRYNTRN and Monte Carlo results.

  13. The dose dependence of glucocorticoid-inducible gene expression results from changes in the number of transcriptionally active templates.

    PubMed Central

    Ko, M S; Nakauchi, H; Takahashi, N

    1990-01-01

    Glucocorticoid hormones induce the transcription of genes having glucocorticoid response elements in a dose dependent manner. To determine whether this dose dependence represents a response of individual templates or of the mass of templates, we introduced a bacterial beta-galactosidase gene linked to the glucocorticoid-inducible enhancer/promoter of the mouse mammary tumor virus (MTV) into Ltk- cells and obtained stable transformants containing a single or a few templates per cell. Visual inspection and flow cytometry analysis by enzyme histochemistry assay for beta-galactosidase revealed that individual cells showed very heterogeneous beta-galactosidase activity after 48 h induction with dexamethasone. When the glucocorticoid concentration was increased, an increasing cell population producing beta-galactosidase was observed. These phenomena were probably not due to heterogeneity of template copy number or to a predetermined cellular state among individual cells, since cells forming a single small colony gave similar results. This was also supported by data showing that recloned cells retained both their responsiveness to the glucocorticoid hormone and their digestion pattern in Southern blotting analyses. These results indicate that the dose dependent increase of glucocorticoid-inducible gene expression is caused by an increase in the number of transcriptionally active templates. Images Fig. 1. Fig. 3. Fig. 4. Fig. 5. Fig. 8. PMID:2167833

  14. Results of loading doses of aspartame by two phenylketonuric (PKU) children compared with two normal children.

    PubMed

    Koch, R; Schaeffler, G; Shaw, N F

    1976-11-01

    Separate tolerance tests with aspartame at 34 mg/kg-day and phenylalanine at 19 mg/kg-day were compared. The results reveal that slight serum elevation of phenylalanine and tyrosine occurred in the two PKU and the normal healthy adolescents. It would appear that the phenylalanine in the sweetener aspartame is small enough to be of little clinical significance.

  15. Exact results in nonequilibrium statistical mechanics: Formalism and applications in chemical kinetics and single-molecule free energy estimation

    NASA Astrophysics Data System (ADS)

    Adib, Artur B.

    In the last two decades or so, a collection of results in nonequilibrium statistical mechanics that departs from the traditional near-equilibrium framework introduced by Lars Onsager in 1931 has been derived, yielding new fundamental insights into far-from-equilibrium processes in general. Apart from offering a more quantitative statement of the second law of thermodynamics, some of these results---typified by the so-called "Jarzynski equality"---have also offered novel means of estimating equilibrium quantities from nonequilibrium processes, such as free energy differences from single-molecule "pulling" experiments. This thesis contributes to such efforts by offering three novel results in nonequilibrium statistical mechanics: (a) The entropic analog of the Jarzynski equality; (b) A methodology for estimating free energies from "clamp-and-release" nonequilibrium processes; and (c) A directly measurable symmetry relation in chemical kinetics similar to (but more general than) chemical detailed balance. These results share in common the feature of remaining valid outside Onsager's near-equilibrium regime, and bear direct applicability in protein folding kinetics as well as in single-molecule free energy estimation.

  16. Preliminary On-Orbit Neutron Dose Equivalent and Energy Spectrum Results from the ISS-RAD Fast Neutron Detector (FND)

    NASA Technical Reports Server (NTRS)

    Semones, Edward; Leitgab, Martin

    2016-01-01

    The ISS-RAD instrument was activated on ISS on February 1st, 2016. Integrated in ISS-RAD, the Fast Neutron Detector (FND) performs, for the first time on ISS, routine and precise direct neutron measurements between 0.5 and 8 MeV. Preliminary results for neutron dose equivalent and neutron flux energy distributions from online/on-board algorithms and offline ground analyses will be shown, along with comparisons to simulated data and previously measured neutron spectral data. On-orbit data quality and pre-launch analysis validation results will be discussed as well.

  17. Bosutinib plus capecitabine for selected advanced solid tumours: results of a phase 1 dose-escalation study

    PubMed Central

    Isakoff, S J; Wang, D; Campone, M; Calles, A; Leip, E; Turnbull, K; Bardy-Bouxin, N; Duvillié, L; Calvo, E

    2014-01-01

    Background: This phase 1 study evaluated the maximum tolerated dose (MTD), safety, and efficacy of bosutinib (competitive Src/Abl tyrosine kinase inhibitor) plus capecitabine. Methods: Patients with locally advanced/metastatic breast, pancreatic, or colorectal cancers; cholangiocarcinoma; or glioblastoma received bosutinib plus capecitabine at eight of nine possible dose combinations using an ‘up-down' design to determine the toxicity contour of the combination. Results: Among 32 enrolled patients, none of the 9 patients receiving MTD (bosutinib 300 mg once daily plus capecitabine 1000 mg m−2 twice daily) experienced dose-limiting toxicities (DLTs). Overall, 2 out of 31 (6%) evaluable patients experienced DLTs (grade 3 neurologic pain (n=1); grade 3 pruritus/rash and increased alanine aminotransferase (n=1)). Most common treatment-related adverse events (AEs) were diarrhoea, nausea, vomiting, palmar-plantar erythrodysesthesia (PPE), fatigue; most frequent grade 3/4 AEs: PPE, fatigue, and increased alanine/aspartate aminotransferase. Although diarrhoea was common, 91% of affected patients experienced maximum grade 1/2 events that resolved. Best overall confirmed partial response or stable disease >24 weeks (all tumour types) was observed in 6 and 13% of patients. Conclusions: In this population of patients with advanced solid tumours, bosutinib plus capecitabine demonstrated a safety profile similar to that previously reported for bosutinib or capecitabine monotherapy; limited efficacy was observed. PMID:25290090

  18. Higher rate of microscopic hematuria in elderly patients who take regular doses of aspirin: Result from AHAP Study

    PubMed Central

    Moudi, Emadouddin; Hosseini, Seyed-Reza; Bijani, Ali

    2016-01-01

    Background: Aspirin is the most widely used drug in medicine for cardiovascular and as recently for its role in cancer prevention. Although the risk of bleeding events increased following regular use of aspirin, little is known about the association of aspirin and hematuria. The present study aimed to evaluate the association of regular aspirin use and microscopic hematuria in elderly. Methods: In this study, we have extracted the data of elderly people who participated in Amirkola Health and Aging Project (AHAP) and taking regular doses of aspirin. The prevalence of microscopic hematuria was compared between the elderly who took aspirin regularly and those who did not take it. Results: A total of 1243 individuals (54.22% males, 45.78% females) were entered in to the study. Two hundred and eighty-four (23%) elderly took regular doses of aspirin. Microscopic hematuria was seen in 305 (24.54%) elderly. The prevalence of microscopic hematuria was 27.27% in regular users of aspirin and 23.72% in non-users of aspirin (P=0.126). The prevalence of microscopic hematuria was significantly higher among the regular users of aspirin compared to non-users in multiple logistic regression analysis (P=0.035, OR=1.40, 95%CI: 1.02-1.92). Conclusion: Taking regular doses of aspirin was accompanied with higher rate of microscopic hematuria in the elderly. PMID:27999646

  19. Three dimensional conformal photon radiotherapy at a moderate dose level of 66 Gy for prostate carcinoma: early results.

    PubMed

    Wachter, S; Gerstner, N; Goldner, G; Dieckmann, K; Colotto, A; Pötter, R

    1999-06-01

    The therapeutic outcome and toxicity of 3-D conformal photon external beam therapy of prostate cancer is well documented in the literature. Progress is still in work for optimization of treatment strategies by risk-adapted dose escalation studies to improve local tumor control without increase of radiation side effects. We present our experience of 291 patients treated between January 1994 and August 1997 with a 3-D planned four-field box technique and a central dose of 66 Gy. Biochemical response of patients with radiotherapy alone (group 1, n = 72 pts.) has been analyzed in detail. Acute radiation side effects are given for all patients (n = 291), late radiation side effects are given for patients treated between Jan 1994 and Jan 1996 with a median follow-up of 22 months (n = 115 pts.). We have observed a biochemical response (nadir PSA < 1 after 12 months, < 2 after 6 months) for patients treated with radiotherapy alone without hormone manipulation in 67%. Incidence of late rectal and bladder morbidity (grade 2 and 3) was 9.4% and 4%, respectively. Compared to other reports our results indicate a high rate of local tumor control (early biochemical response) and a low rate of late morbidity. Nevertheless, we will start a risk-adapted dose escalation study up to 74 Gy for unfavorable subgroups (G2-3, Gleason Score > 7, PSA > 10) to improve treatment outcome.

  20. [Ranking of radionuclides and pathways according to their contribution to the dose burden to the population resulting from NPP releases].

    PubMed

    Spiridonov, S I; Karpenko, E I; Sharpan, L A

    2013-01-01

    Approaches are described towards estimating the consequences of radioactive contamination of ecosystems by nuclear fuel cycle enterprises with the rationale for the optimal specification level for nuclear power plants (NPP) operating in the normal mode. Calculations are made based on the initial data of the IAEA project, INPRO ENV, dealing with the ranking of radionuclides escaping to the environment from the operating NPPs. Influence of various factors on rankings of radionuclides and pathways of public exposure is demon- strated. An important factor is the controlled radionuclide composition of atmospheric NPP releases. It has been found that variation in the dose coefficients for some radionuclides leads to significant changes not only in the ranking results but also in the estimates of total dose burdens. Invariability is shown of the estimation concerning the greatest contribution of the peroral route to the population dose of irradiation in the situation considered. A conclusion was drawn on the need of taking into consideration uncertainties of different factors when comparing effects on the environment from enterprises of conventional and innovative nuclear fuel cycles.

  1. Low-Dose Gamma Irradiation of Decellularized Heart Valves Results in Tissue Injury in Vitro and in Vivo

    PubMed Central

    Helder, Meghana R. K.; Hennessy, Ryan S.; Spoon, Daniel B.; Tefft, Brandon J.; Witt, Tyra A.; Marler, Ronald J.; Pislaru, Sorin V.; Simari, Robert D.; Stulak, John M.; Lerman, Amir

    2017-01-01

    Background Decellularized heart valves are emerging as a potential alternative to current bioprostheses for valve replacement. While techniques of decellularization have been thoroughly examined, terminal sterilization techniques have not received the same scrutiny. Methods This study evaluated low dose gamma irradiation as a sterilization method for decellularized heart valves. Incubation of valves and transmission electron microscopy evaluation after different doses of gamma irradiation were used to determine the optimal dose of gamma irradiation. Quantitative evaluation of mechanical properties was done by tensile mechanical testing of isolated cusps. Sterilize decellularized heart valves were tested in a sheep model (n=3, 1 1,500 Gy and 2 3,000 Gy) of pulmonary valve replacement. Results Valves sterilized with gamma radiation between 1,000 Gy and 3,000 Gy were found to be optimal with in-vitro testing. However, with in-vivo showed deteriorating valve function within 2 months. On explant the valve with 1,500 Gy gamma irradiation showed signs of endocarditis with neutrophils on hematoxylin and eosin staining, positive gram stain resembling streptococcus infection. The 3,000 Gy valves had no evidence of infection, but the hematoxylin and eosin staining showed evidence of wound remodeling with macrophages and fibroblasts. Tensile strength testing showed decreased strength (0 Gy-2.53±0.98 MPa, 1,500 Gy-2.03±1.23 MPa, 3,000 Gy-1.26±0.90 MPa) with increasing levels of irradiation. Conclusions Low dose gamma irradiation does not maintain the mechanical integrity of valves and the balance between sterilization and damage may not be able to be achieved with gamma irradiation. Other methods of terminal sterilization must be pursued and evaluated. PMID:26453425

  2. Estimates of inhalation doses resulting from the possible use of phospho-gypsum plaster-board in Australian homes.

    PubMed

    O'Brien, R S; Peggie, J R; Leith, I S

    1995-04-01

    Current materials used as internal lining in Australian buildings are based on natural gypsum of low radium content. A study was carried out to estimate the contribution to the annual effective dose due to airborne contamination from chemical by-product gypsum plaster-board of higher radium content if it were used as an internal lining. The 226Ra content and 222Rn exhalation rate were measured for several samples of the plaster-board, and the behavior of 222Rn and its progeny (218Po, 214Pb, 214Bi, and 214Po) in a typical building was modeled numerically, using the results of the exhalation rate measurements as input. For building ventilation rates greater than approximately 0.5 air changes per hour, the contribution to the total annual effective dose from inhalation of 222Rn and its progeny exhaled from the phospho-gypsum plaster-board is estimated to be below 1 mSv. This contribution is reduced if the surface of the plaster-board is coated with paint or cardboard, or if the very fine particles are removed from the phospho-gypsum during manufacture of the plaster-board. The effective doses arising from dust generation during the installation of the plaster-board are also estimated to be below 1 mSv. The recommended action level of 200 Bq m-3 for radon in air in Australia corresponds to an annual effective dose of approximately 6 mSv. The study indicates that the suggested acceptable level of 185 Bq kg-1 for the 226Ra concentration in the plaster-board may be too restrictive under Australian conditions.

  3. Local Control Following Permanent Prostate Brachytherapy: Effect of High Biologically Effective Dose on Biopsy Results and Oncologic Outcomes

    SciTech Connect

    Stone, Nelson N.; Stock, Richard G.; Cesaretti, Jamie A.; Unger, Pam

    2010-02-01

    Purpose: To determine factors that influence local control and systemic relapse in patients undergoing permanent prostate brachytherapy (PPB). Methods and Materials: A total of 584 patients receiving PPB alone or PPB with external beam radiation therapy (19.5%) agreed to undergo prostate biopsy (PB) at 2 years postimplantion and yearly if results were positive or if the prostate-specific antigen (PSA) level increased. Short-term hormone therapy was used with 280 (47.9%) patients. Radiation doses were converted to biologically effective doses (BED) (using alpha/beta = 2). Comparisons were made by chi-square analysis and linear regression. Survival was determined by the Kaplan-Meier method. Results: The median PSA concentration was 7.1 ng/ml, and the median follow-up period was 7.1 years. PB results were positive for 48/584 (8.2%) patients. Positive biopsy results by BED group were as follows: 22/121 (18.2%) patients received a BED of <=150 Gy; 15/244 (6.1%) patients received >150 to 200 Gy; and 6/193 (3.1%; p < 0.001) patients received >200 Gy. Significant associations of positive PB results by risk group were low-risk group BED (p = 0.019), intermediate-risk group hormone therapy (p = 0.011) and BED (p = 0.040), and high-risk group BED (p = 0.004). Biochemical freedom from failure rate at 7 years was 82.7%. Biochemical freedom from failure rate by PB result was 84.7% for negative results vs. 59.2% for positive results (p < 0.001). Cox regression analysis revealed significant associations with BED (p = 0.038) and PB results (p = 0.002) in low-risk patients, with BED (p = 0.003) in intermediate-risk patients, and with Gleason score (p = 0.006), PSA level (p < 0.001), and PB result (p = 0.038) in high-risk patients. Fifty-three (9.1%) patients died, of which eight deaths were due to prostate cancer. Cause-specific survival was 99.2% for negative PB results vs. 87.6% for positive PB results (p < 0.001). Conclusions: Higher radiation doses are required to achieve local

  4. Impact of Assimilation on Heavy Rainfall Simulations Using WRF Model: Sensitivity of Assimilation Results to Background Error Statistics

    NASA Astrophysics Data System (ADS)

    Rakesh, V.; Kantharao, B.

    2017-03-01

    Data assimilation is considered as one of the effective tools for improving forecast skill of mesoscale models. However, for optimum utilization and effective assimilation of observations, many factors need to be taken into account while designing data assimilation methodology. One of the critical components that determines the amount and propagation observation information into the analysis, is model background error statistics (BES). The objective of this study is to quantify how BES in data assimilation impacts on simulation of heavy rainfall events over a southern state in India, Karnataka. Simulations of 40 heavy rainfall events were carried out using Weather Research and Forecasting Model with and without data assimilation. The assimilation experiments were conducted using global and regional BES while the experiment with no assimilation was used as the baseline for assessing the impact of data assimilation. The simulated rainfall is verified against high-resolution rain-gage observations over Karnataka. Statistical evaluation using several accuracy and skill measures shows that data assimilation has improved the heavy rainfall simulation. Our results showed that the experiment using regional BES outperformed the one which used global BES. Critical thermo-dynamic variables conducive for heavy rainfall like convective available potential energy simulated using regional BES is more realistic compared to global BES. It is pointed out that these results have important practical implications in design of forecast platforms while decision-making during extreme weather events

  5. Cinacalcet HCl and Concurrent Low-dose Vitamin D Improves Treatment of Secondary Hyperparathyroidism in Dialysis Patients Compared with Vitamin D Alone: The ACHIEVE Study Results

    PubMed Central

    Fishbane, Steven; Shapiro, Warren B.; Corry, Dalila B.; Vicks, Steven L.; Roppolo, Michael; Rappaport, Kenneth; Ling, Xiang; Goodman, William G.; Turner, Stewart; Charytan, Chaim

    2008-01-01

    Background and objectives: Patients with chronic kidney disease (CKD) receiving dialysis often develop secondary hyperparathyroidism with disturbed calcium and phosphorus metabolism. The National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (KDOQI) was established to guide treatment practices for these disorders. The ACHIEVE study was designed to test two treatment strategies for achieving KDOQI goals. Design, setting, participants, measurements: Individuals on hemodialysis treated with vitamin D sterols were enrolled in this 33-week study. Subjects were randomly assigned to treatment with either cinacalcet and low-dose vitamin D (Cinacalcet-D) or flexible vitamin D alone (Flex-D) to achieve KDOQI-recommended bone mineral targets. ACHIEVE included a 6-week screening phase, including vitamin D washout, a 16-week dose-titration phase, and an 11-week assessment phase. Results: Of 173 subjects enrolled, 83% of Cinacalcet-D and 67% of Flex-D subjects completed the study. A greater proportion of Cinacalcet-D versus Flex-D subjects had a ≥30% reduction in parathyroid hormone (PTH) (68% versus 36%, P < 0.001) as well as PTH ≤300 pg/ml (44% versus 23%, P = 0.006). The proportion of subjects simultaneously achieving targets for intact PTH (150–300 pg/ml) and calcium-phosphorus product (Ca×P) (<55 mg2/dl2) was also greater (21% versus 14%), but this was not statistically significant. This was attributable to 19% of Cinacalcet-D subjects with a PTH value below the KDOQI target range. Conclusions: Achievement of KDOQI targets was difficult, especially with Flex-D. Maintaining calcium and phosphorus target values precluded the use of vitamin D doses necessary to lower PTH to within the narrow target range and highlighted limitations inherent to the KDOQI treatment algorithm. PMID:18945995

  6. Late Gastrointestinal Toxicity After Dose-Escalated Conformal Radiotherapy for Early Prostate Cancer: Results From the UK Medical Research Council RT01 Trial (ISRCTN47772397)

    SciTech Connect

    Syndikus, Isabel; Morgan, Rachel C.; Sydes, Matthew R.; Graham, John D.; Dearnaley, David P.

    2010-07-01

    Purpose: In men with localized prostate cancer, dose-escalated conformal radiotherapy (CFRT) improves efficacy outcomes at the cost of increased toxicity. We present a detailed analysis to provide further information about the incidence and prevalence of late gastrointestinal side effects. Methods and Materials: The UK Medical Research Council RT01 trial included 843 men with localized prostate cancer, who were treated for 6 months with neoadjuvant radiotherapy and were randomly assigned to either 64-Gy or 74-Gy CFRT. Toxicity was evaluated before CFRT and during long-term follow-up using Radiation Therapy Oncology Group (RTOG) grading, the Late Effects on Normal Tissue: Subjective, Objective, Management (LENT/SOM) scale, and Royal Marsden Hospital assessment scores. Patients regularly completed Functional Assessment of Cancer Therapy--Prostate (FACT-P) and University of California, Los Angeles, Prostate Cancer Index (UCLA-PCI) questionnaires. Results: In the dose-escalated group, the hazard ratio (HR) for rectal bleeding (LENT/SOM grade {>=}2) was 1.55 (95% CI, 1.17-2.04); for diarrhea (LENT/SOM grade {>=}2), the HR was 1.79 (95% CI, 1.10-2.94); and for proctitis (RTOG grade {>=}2), the HR was 1.64 (95% CI, 1.20-2.25). Compared to baseline scores, the prevalence of moderate and severe toxicities generally increased up to 3 years and than lessened. At 5 years, the cumulative incidence of patient-reported severe bowel problems was 6% vs. 8% (standard vs. escalated, respectively) and severe distress was 4% vs. 5%, respectively. Conclusions: There is a statistically significant increased risk of various adverse gastrointestinal events with dose-escalated CFRT. This remains at clinically acceptable levels, and overall prevalence ultimately decreases with duration of follow-up.

  7. Local control following permanent prostate brachytherapy: effect of high biologically effective dose on biopsy results and oncologic outcomes.

    PubMed

    Stone, Nelson N; Stock, Richard G; Cesaretti, Jamie A; Unger, Pam

    2010-02-01

    To determine factors that influence local control and systemic relapse in patients undergoing permanent prostate brachytherapy (PPB). A total of 584 patients receiving PPB alone or PPB with external beam radiation therapy (19.5%) agreed to undergo prostate biopsy (PB) at 2 years postimplantion and yearly if results were positive or if the prostate-specific antigen (PSA) level increased. Short-term hormone therapy was used with 280 (47.9%) patients. Radiation doses were converted to biologically effective doses (BED) (using alpha/beta = 2). Comparisons were made by chi-square analysis and linear regression. Survival was determined by the Kaplan-Meier method. The median PSA concentration was 7.1 ng/ml, and the median follow-up period was 7.1 years. PB results were positive for 48/584 (8.2%) patients. Positive biopsy results by BED group were as follows: 22/121 (18.2%) patients received a BED of < or =150 Gy; 15/244 (6.1%) patients received >150 to 200 Gy; and 6/193 (3.1%; p < 0.001) patients received >200 Gy. Significant associations of positive PB results by risk group were low-risk group BED (p = 0.019), intermediate-risk group hormone therapy (p = 0.011) and BED (p = 0.040), and high-risk group BED (p = 0.004). Biochemical freedom from failure rate at 7 years was 82.7%. Biochemical freedom from failure rate by PB result was 84.7% for negative results vs. 59.2% for positive results (p < 0.001). Cox regression analysis revealed significant associations with BED (p = 0.038) and PB results (p = 0.002) in low-risk patients, with BED (p = 0.003) in intermediate-risk patients, and with Gleason score (p = 0.006), PSA level (p < 0.001), and PB result (p = 0.038) in high-risk patients. Fifty-three (9.1%) patients died, of which eight deaths were due to prostate cancer. Cause-specific survival was 99.2% for negative PB results vs. 87.6% for positive PB results (p < 0.001). Higher radiation doses are required to achieve local control following PPB. A BED of >200 Gy with an

  8. Statistical analysis of results from the 1995 survey of CFC consumption on US Navy ships. Technical report

    SciTech Connect

    Burns, K.C.; Smith, D.E.

    1995-08-01

    The production of chlorofluorocarbon (CFC) refrigerants will cease in the United States at the end of 1995. The Naval Sea Systems Command (NAVSEA) needs to monitor total fleet requirements of CFCs until they are phased out. Stockpile requirements for ozone-depleting substances were determined from the results of a survey covering the period from 1 May 1993 to 30 April 1994. A second survey was conducted for the period from 1 May 1994 to 30 April 1995 for two primary reasons: to provide additional nformation on reserve requirements and to measure the effects of policies designed to reduce fleet CFC consumption. This report provides a statistical analysis of the data from the new survey, which includes reported usage for CFC-ll, CFC-12, and CFC-114. The new results are compared to those from the earlier survey, showing a significant reduction in CFC usage. Summary information in the report can be used to refine estimates of reserve requirements.

  9. Isolated vaginal recurrences in endometrial carcinoma: treatment results using high-dose-rate intracavitary brachytherapy and external beam radiotherapy.

    PubMed

    Pai, H H; Souhami, L; Clark, B G; Roman, T

    1997-08-01

    To evaluate the long-term disease control, survival and complication rates using high-dose-rate intracavitary brachytherapy (HDRB) and external beam radiotherapy (EBRT) for patients found to have isolated vaginal recurrences from early-stage endometrial adenocarcinoma following total abdominal hysterectomy and bisalpingo-oophorectomy (TAH BSO). Twenty patients originally diagnosed with early-stage endometrial adenocarcinoma (FIGO stage I or II) following TAH BSO developed isolated vaginal recurrences and were referred to our radiation oncology department for definitive treatment. The median time between TAH BSO and vaginal recurrence was 24 months. Thirteen patients received combined modality treatment (EBRT + HDRB) and seven patients received HDRB only. Median prescribed dose was 4400 cGy by EBRT and 2400 cGy to the vagina mucosa surface by HDRB in the combined modality group. Median prescribed dose was 3500 cGy to the vagina mucosa surface for the HDRB only group. These patients were followed for a median duration of 47.5 months following treatment for isolated vaginal recurrence. Eighteen of 20 patients (90%) achieved a complete response to therapy and the remaining 2 achieved a partial response. Four of 18 complete responders developed a second recurrence within 30 months following radiotherapy. Ten-year cumulative local control rate was 74%. Ten-year cumulative cause specific and disease-free survival rate was 71 and 46%. Overall late complication rate was 15%; there were no grade 3 or 4 late complications. Three patients developed grade 2 late complications from treatment; all 3 were from the combined modality group (HDRB + EBRT). The use of HDRB resulted in high complete response rates and durable long-term disease-specific survival in a substantial percentage of patients. To our knowledge, this study represents the first published results on treatment of vaginal recurrences with HDRB. Although the number of patients in this study is small, treatment results

  10. Intradermal vaccination of pigs against FMD with 1/10 dose results in comparable vaccine efficacy as intramuscular vaccination with a full dose.

    PubMed

    Eblé, P L; Weerdmeester, K; van Hemert-Kluitenberg, F; Dekker, A

    2009-02-18

    The aim of this study was to investigate whether intradermal (ID) vaccination against foot-and-mouth disease (FMD) is suitable as an alternative for the usually used intramuscular (IM) route. We compared vaccine efficacy in groups of pigs in which vaccine administration differed with respect to antigen payload of the vaccine, administrated volume and administration route. When compared with pigs that were IM vaccinated with a full dose vaccine with a standard antigen payload, pigs vaccinated ID with 1/10 dose of the same vaccine were equally protected against clinical disease and subclinical virus shedding. The ID vaccinated pigs were protected against virus shedding at a significant lower VN-titre as compared to IM vaccinated pigs, suggesting that immune responses other than neutralising antibodies also contributed to protection. We conclude that the ID route might be a good alternative for IM application, as ID application might induce a very efficient immunological response against FMD and, moreover, because the dose required by the ID route is lower compared to the IM route, ID application may reduce the production costs per dose of FMD vaccine markedly.

  11. Dose Accuracy of the ClikSTAR, NovoPen 4, and Luxura Insulin Pens: Results of Laboratory and Field Studies

    PubMed Central

    Friedrichs, Arnd; Basso, Nils; Adler, Steffen

    2011-01-01

    Background A high dosing accuracy is needed to maintain normal glycemia in patients with diabetes. This study investigated the dose accuracy of the commonly used reusable insulin pens ClikSTAR®, NovoPen® 4, and Luxura®. Methods Pens were tested in a laboratory setting by one trained technician who delivered four doses of 30 U from each of 15 pens per pen model (a total of 60 doses from each pen model). Pens were also tested in a simulated clinical setting by 48 people with diabetes. Each participant delivered 27 doses: three doses of 30 U from each of three pens per pen model. Overall, the technician delivered 180 doses and the participants 1296 doses. Results All pens met the tolerance limits defined by the German edition of the International Standardization Organization (ISO) 11608-1:2000 standard [30 ± 1.5 U (28.5–31.5 U)]. All doses were delivered within the limits proposed by the ISO, except for two doses with Luxura in the clinical setting. In laboratory testing, the mean dose delivered by ClikSTAR (29.69 U) or Luxura (29.89 U) was less than the expected 30 U and significantly less than the mean dose delivered by NovoPen 4 (30.04 U; p < .001 for both comparisons). Similar results were observed in the simulated clinical setting. NovoPen 4 had the greatest variance in laboratory testing but the least in the simulated clinical setting. Conclusions This study demonstrates comparable dose accuracy and variability of the ClikSTAR, Luxura, and NovoPen 4 insulin pens. The slight differences in mean doses between pens are unlikely to be clinically significant. PMID:22027314

  12. Long-term outcomes from dose-escalated image-guided intensity-modulated radiotherapy with androgen deprivation: encouraging results for intermediate- and high-risk prostate cancer

    PubMed Central

    Wilcox, Shea W; Aherne, Noel J; Benjamin, Linus C; Wu, Bosco; de Campos Silva, Thomaz; McLachlan, Craig S; McKay, Michael J; Last, Andrew J; Shakespeare, Thomas P

    2014-01-01

    Purpose Dose-escalated (DE) radiotherapy in the setting of localized prostate cancer has been shown to improve biochemical disease-free survival (bDFS) in several studies. In the same group of patients, androgen deprivation therapy (ADT) has been shown to confer a survival benefit when combined with radiotherapy doses of up to 70 Gy; however, there is currently little long-term data on patients who have received high-dose intensity-modulated radiotherapy (IMRT) with ADT. We report the long-term outcomes in a large cohort of patients treated with the combination of DE image-guided IMRT (IG-IMRT) and ADT. Methods and materials Patients with localized prostate cancer were identified from a centralized database across an integrated cancer center. All patients received DE IG-IMRT, combined with ADT, and had a minimum follow up of 12 months post-radiotherapy. All relapse and toxicity data were collected prospectively. Actuarial bDFS, metastasis-free survival, prostate cancer-specific survival, and multivariate analyses were calculated using the SPSS v20.0 statistical package. Results Seven hundred and eighty-two eligible patients were identified with a median follow up of 46 months. Overall, 4.3% of patients relapsed, 2.0% developed distant metastases, and 0.6% died from metastatic prostate cancer. At 5-years, bDFS was 88%, metastasis-free survival was 95%, and prostate cancer-specific survival was 98%. Five-year grade 2 genitourinary and gastrointestinal toxicity was 2.1% and 3.4%, respectively. No grade 3 or 4 late toxicities were reported. Pretreatment prostate specific antigen (P=0.001) and Gleason score (P=0.03) were significant in predicting biochemical failure on multivariate analysis. Conclusion There is a high probability of tumor control with DE IG-IMRT combined with androgen deprivation, and this is a technique with a low probability of significant late toxicity. Our long term results corroborate the safety and efficacy of treating with IG-IMRT to high doses

  13. Statistical modelling of rainfall-induced shallow landsliding using static predictors and numerical weather predictions: preliminary results

    NASA Astrophysics Data System (ADS)

    Capecchi, V.; Perna, M.; Crisci, A.

    2015-01-01

    Our study is aimed at estimating the added value provided by Numerical Weather Prediction (NWP) data for the modelling and prediction of rainfall-induced shallow landslides. We implemented a quantitative indirect statistical modelling of such phenomena by using, as input predictors, both geomorphological, geological, climatological information and numerical data obtained by running a limited-area weather model. Two standard statistical techniques are used to combine the predictor variables: a generalized linear model and Breiman's random forests. We tested these models for two rainfall events that occurred in 2011 and 2013 in Tuscany region (central Italy). Modelling results are compared with field data and the forecasting skill is evaluated by mean of sensitivity-specificity receiver operating characteristic (ROC) analysis. In the 2011 rainfall event, the random forests technique performs slightly better than generalized linear model with area under the ROC curve (AUC) values around 0.91 vs. 0.84. In the 2013 rainfall event, both models provide AUC values around 0.7. Using the variable importance output provided by the random forests algorithm, we assess the added value carried by numerical weather forecast. The main results are as follows: (i) for the rainfall event that occurred in 2011 most of the NWP data, and in particular hourly rainfall intensities, are classified as "important" and (ii) for the rainfall event that occurred in 2013 only NWP soil moisture data in the first centimetres below ground is found to be relevant for landslide assessment. In the discussions we argue how these results are connected to the type of precipitation observed in the two events.

  14. Mean Organ Doses Resulting From Non-Human Primate Whole Thorax Lung Irradiation Prescribed to Mid-Line Tissue.

    PubMed

    Prado, Charlotte; Kazi, Abdul; Bennett, Alexander; MacVittie, Thomas; Prado, Karl

    2015-11-01

    Multi-organ dose evaluations and the effects of heterogeneous tissue dose calculations have been retrospectively evaluated following irradiation to the whole thorax and lung in non-human primates (NHP). A clinical-based approach was established to evaluate actual doses received in the heart and lungs during whole thorax lung irradiation. Anatomical structure and organ densities have been introduced in the calculations to show the effects of dose distribution through heterogeneous tissue. Mean organ doses received by non-human primates undergoing whole thorax lung irradiations were calculated using a treatment planning system that is routinely used in clinical radiation oncology. The doses received by non-human primates irradiated following conventional dose calculations have been retrospectively reconstructed using computerized tomography-based, heterogeneity-corrected dose calculations. The use of dose volume descriptors for irradiation to organs at risk and tissue exposed to radiation is introduced. Mean and partial-volume doses to lung and heart are presented and contrasted. The importance of exact dose definitions is highlighted, and the relevance of precise dosimetry to establish organ-specific dose response relationships in NHP models of acute and delayed effects of acute radiation exposure is emphasized.

  15. Differential cytokine induction by doses of lipopolysaccharide and monophosphoryl lipid A that result in equivalent early endotoxin tolerance.

    PubMed Central

    Henricson, B E; Benjamin, W R; Vogel, S N

    1990-01-01

    The phenomenon of early endotoxin tolerance, which is induced by sublethal injection of lipopolysaccharide (LPS), results in a protracted period of hyporesponsiveness that is most profound at 3 to 4 days after injection and is marked by reduced cytokine production after a challenge injection of LPS. Early endotoxin tolerance is also induced by the nontoxic LPS derivative monophosphoryl lipid A (MPL), although much more of the monophosphoryl derivative is required to produce a state of tolerance equivalent to that evoked by LPS. In this study, equivalent tolerance-inducing doses of LPS and MPL were tested, and the levels of cytokines induced by LPS and MPL were compared. Although induced levels of colony-stimulating factor were comparable following doses of LPS and MPL that elicited an equivalent state of early endotoxin tolerance, levels of tumor necrosis factor, interleukin-6, and interferon were significantly lower in MPL-injected animals. These results suggest that the lowered toxicity of MPL may be related to its elicitation of significantly lower levels of potentially toxic intermediaries such as tumor necrosis factor, interferon, and interleukin-6. PMID:1695201

  16. Results of a Conservative Dose Plan Linear Accelerator-Based Stereotactic Radiosurgery for Pediatric Intracranial Arteriovenous Malformations.

    PubMed

    Rajshekhar, Vedantam; Moorthy, Ranjith K; Jeyaseelan, Visalakshi; John, Subhashini; Rangad, Faith; Viswanathan, P N; Ravindran, Paul; Singh, Rabiraja

    2016-11-01

    To evaluate the obliteration rate and clinical outcome following linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) for intracranial arteriovenous malformation (AVM) in pediatric patients (age ≤18 years). Factors associated with the obliteration rate and neurologic complications were studied retrospectively in pediatric patients who underwent LINAC-based SRS for AVM between June 1995 and May 2014. The study cohort comprised 36 males and 33 females, with a median age at the time of SRS of 14 years (range, 7-18 years). The mean AVM volume was 8.5 ± 8.7 cc (range, 0.6-41.8 cc). The median marginal dose of radiation delivered was 15 Gy (range, 9-20 Gy). Magnetic resonance imaging (MRI) demonstrated complete obliteration of the AVM in 44 of the 69 patients (63.8%), at a mean follow up of 27.5 months (range, 12-90 months). On subgroup analysis, 41 of the 53 AVMs of ≤14 cc in volume (77.3%) were obliterated. AVMs with a modified AVM radiosurgery score <1 had significantly shorter obliteration times from the time of SRS (P = .006). On multivariate analysis, the mean marginal dose of radiation delivered to the AVM was the sole significant predictor of obliteration (odds ratio, 1.6; 95% confidence interval, 1 to 2.4). A modest median marginal dose of 15 Gy (16 Gy in the obliterated AVM group vs. 12 Gy in the nonobliterated group) resulted in an obliteration rate of 66.7% after LINAC-based SRS for intracranial AVM, with low rate. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Sevelamer hydrochloride dose-dependent increase in prevalence of severe acidosis in hemodialysis patients: analysis of nationwide statistical survey in Japan.

    PubMed

    Oka, Yoshinari; Miyazaki, Masashi; Matsuda, Hiroaki; Takatsu, Shigeko; Katsube, Ryouichi; Mori, Toshiko; Takehara, Kiyoto; Umeda, Yuzo; Uno, Futoshi

    2014-02-01

    Metabolic acidosis has a negative impact on prognosis of dialysis patients. The aim of this study was to determine the prevalence of severe metabolic acidosis in dialysis patients treated with sevelamer hydrochloride. In 2004, a nationwide survey (101,516 dialysis patients) was conducted by the Japanese Society for Dialysis Therapy. We analyzed 32,686 dialysis patients whose bicarbonate levels were measured in the survey. Sevelamer hydrochloride was prescribed to 9231 dialysis patients while 23,455 dialysis patients were not prescribed sevelamer hydrochloride. In the present study, we defined severe acidosis as bicarbonate <15.8 mmol/L. The mean serum bicarbonate level correlated significantly and negatively with the daily dose of sevelamer hydrochloride (R(2) = 0.806, P < 0.0001). Logistic regression analysis indicated that the percentage of patients with severe acidosis increased significantly with increased dose of sevelamer hydrochloride (R(2) = 0.885, P < 0.00001). The estimated doses of sevelamer hydrochloride associated with severe acidosis in 10% and 15% of patients were 3.5 g/day (95% confidence interval [95%CI], 2.8-4.4) and 7.7 g/day (95%CI = 5.9-10.9), respectively. Severe acidosis was noted in 4.5% of patients who were not treated with sevelamer hydrochloride and in 16.1% of patients treated with sevelamer hydrochloride at ≥ 5.25 g/day (P < 0.0001). The results call for careful monitoring of serum bicarbonate level in hemodialysis patients treated with sevelamer hydrochloride. © 2013 The Authors. Therapeutic Apheresis and Dialysis © 2013 International Society for Apheresis.

  18. The magnitude of neurotoxicity in patients with multiple myeloma and the impact of dose modifications: results from the population-based PROFILES registry.

    PubMed

    Beijers, Antoinetta J M; Oerlemans, Simone; Mols, Floortje; Eurelings, Marijke; Minnema, Monique C; Vreugdenhil, Art; van de Poll-Franse, Lonneke V

    2017-04-01

    The aim of this analysis is to assess (1) self-reported chemotherapy-induced peripheral neuropathy (CIPN) symptoms; (2) its association with sociodemographic and clinical characteristics; and (3) treatment dose modifications and its influence on the magnitude of neurotoxicity in a population-based cohort of patients with multiple myeloma (MM). MM patients (n = 156), diagnosed between 2000 and 2014, filled out the EORTC QLQ-CIPN20 (65% response). Data on treatment, outcomes, and dose modifications were extracted from the medical files. Fifty-three percent of patients reported at least one and on average three neuropathy symptoms that bothered them the most during the past week, with tingling toes/feet as most reported. In multivariate analysis, thalidomide, especially higher cumulative dose, was associated with neuropathy (β = 0.26, CI 95% 0.27-15.34, p = 0.04) and CIPN was not associated with age, sex, time since last course of therapy, number of prior therapies, osteoarthritis, or diabetes. Dose modifications were often applied (65%). Although not statistically significant, a trend towards higher sensory (22 vs. 15 vs. 12, p = 0.22) and motor neuropathy scores (21 vs. 15 vs. 11, p = 0.36) was observed among patients receiving dose modification because of CIPN (31%) compared to those receiving a dose modification for another reason or no dose modification, without altering treatment response. CIPN is a common dose limiting side effect in patients with MM. Severity of CIPN was mainly affected by treatment with thalidomide. In spite of dose modifications, patients still reported somewhat higher neuropathy scores without altered response rates. Early dose modification based on a more reliable tool for CIPN measurements may prove value.

  19. Negative clinical results from a randomised, double-blind, placebo-controlled trial evaluating the efficacy of two doses of immunologically enhanced, grass subcutaneous immunotherapy despite dose-dependent immunological response.

    PubMed

    Kleine-Tebbe, Jörg; Walmar, Mikkel; Bitsch-Jensen, Klaus; Decot, Elke; Pfaar, Oliver; de Rojas, Dolores Hernández Fernández; Rodriguez, Fernando

    2014-08-01

    Specific immunotherapy is the only treatment for the underlying allergic disease in patients with respiratory allergies. The primary objective of this trial was to evaluate the efficacy and safety of two maintenance doses of immunologically enhanced, standardised quality (SQ+) grass subcutaneous immunotherapy (SCIT) [4,000 SQ+ and 15,000 SQ+; AVANZ(®) Phleum pratense (ALK)] compared with placebo. This was a randomised, double-blind, placebo-controlled, phase II/III trial. The primary evaluation was based on the combined rhinoconjunctivitis score during the entire grass pollen season. Adult subjects with grass pollen-induced allergic rhinoconjunctivitis interfering with usual activities or sleep despite symptomatic medication use, were enrolled. Four hundred and fifty subjects were randomised to receive either 4,000 SQ+ (n = 150), 15,000 SQ+ (n = 152) or placebo (n = 148). The average grass pollen exposure was 27 grains/m(3)/day. No statistically significant differences between the active groups and the placebo group were found for clinical endpoints (p > 0.05). Highly statistically significant (p < 0.001) increases in IgG4 and IgE-blocking factor were found for both active groups versus placebo. The most frequently reported adverse events were mild-to-moderate local injection-site reactions; events were generally more frequent with 15,000 SQ+ than with 4,000 SQ+ and placebo. The most common adverse events leading to premature discontinuation from the trial were anaphylactic reactions (one subject from the placebo group and five subjects from the 15,000 SQ+ group). The inconclusive results were most probably influenced by a very low grass pollen season. Other factors such as the extent of the pre-seasonal treatment could potentially have contributed. The tolerability profile was acceptable for further development.

  20. Characterization of chlamydial genital infection resulting from sexual transmission from male to female guinea pigs and determination of infectious dose.

    PubMed

    Rank, Roger G; Bowlin, Anne K; Reed, Ronald L; Darville, Toni

    2003-11-01

    A major problem in the study of chlamydial genital infections in animal models has been the use of varied doses of chlamydiae for infection in different laboratories. It is clearly desirable to use a dose which approximates that of natural sexual infection, but that dose to date has not been determined because of the inability of researchers to quantify chlamydiae in semen. Fortunately, sexual transmission of chlamydiae has been described for the guinea pig model of infection with the chlamydial agent of guinea pig inclusion conjunctivitis (GPIC). In this study, we undertook to determine the approximate infection dose in actual sexual transmission by comparing the kinetics of infection in female guinea pigs acquired via sexual contact to those of genital infections induced artificially with known quantities of chlamydiae. Groups of guinea pigs were infected intravaginally with 10(4), 10(3), 10(2), and 10(1) inclusion-forming units (IFU) of GPIC, and the kinetics of the infection were determined. Infection with 10(2) IFU produced infections with lower peak levels than those in animals receiving 10(4) or 10(3) IFU. Seventy percent of animals receiving 10(2) IFU became infected, while 100 and 79% of animals receiving 10(4) and 10(3) IFU, respectively, became infected. Animals receiving 10(2) IFU also had a longer incubation period. Of 19 animals that mated with infected males, 63.2% became infected, with an infection course which was not significantly different than that of the 10(2)-IFU-infected group. The data suggest that female guinea pigs received approximately 10(2) IFU by sexual transmission. Of interest was the observation that the guinea pigs infected by sexual transmission shed organisms for a significantly shorter time period than that of any group that was artificially infected. This result suggests that there may be factors associated with semen which passively transfer antimicrobial activity to the female or enhance the innate host response in the female

  1. Characterization of Chlamydial Genital Infection Resulting from Sexual Transmission from Male to Female Guinea Pigs and Determination of Infectious Dose

    PubMed Central

    Rank, Roger G.; Bowlin, Anne K.; Reed, Ronald L.; Darville, Toni

    2003-01-01

    A major problem in the study of chlamydial genital infections in animal models has been the use of varied doses of chlamydiae for infection in different laboratories. It is clearly desirable to use a dose which approximates that of natural sexual infection, but that dose to date has not been determined because of the inability of researchers to quantify chlamydiae in semen. Fortunately, sexual transmission of chlamydiae has been described for the guinea pig model of infection with the chlamydial agent of guinea pig inclusion conjunctivitis (GPIC). In this study, we undertook to determine the approximate infection dose in actual sexual transmission by comparing the kinetics of infection in female guinea pigs acquired via sexual contact to those of genital infections induced artificially with known quantities of chlamydiae. Groups of guinea pigs were infected intravaginally with 104, 103, 102, and 101 inclusion-forming units (IFU) of GPIC, and the kinetics of the infection were determined. Infection with 102 IFU produced infections with lower peak levels than those in animals receiving 104 or 103 IFU. Seventy percent of animals receiving 102 IFU became infected, while 100 and 79% of animals receiving 104 and 103 IFU, respectively, became infected. Animals receiving 102 IFU also had a longer incubation period. Of 19 animals that mated with infected males, 63.2% became infected, with an infection course which was not significantly different than that of the 102-IFU-infected group. The data suggest that female guinea pigs received approximately 102 IFU by sexual transmission. Of interest was the observation that the guinea pigs infected by sexual transmission shed organisms for a significantly shorter time period than that of any group that was artificially infected. This result suggests that there may be factors associated with semen which passively transfer antimicrobial activity to the female or enhance the innate host response in the female. Immunization of females

  2. Sexual Function After Three-Dimensional Conformal Radiotherapy for Prostate Cancer: Results From a Dose-Escalation Trial

    SciTech Connect

    Wielen, Gerard J. van der . E-mail: g.vanderwielen@erasmusmc.nl; Putten, Wim van; Incrocci, Luca

    2007-06-01

    Purpose: The purpose of this study is to provide information about sexual function (SF) after three-dimensional conformal radiotherapy (3D-CRT) for prostate cancer while taking important factors into account that influence SF. Methods and Materials: Between June 1997 and February 2003, a total of 268 patients from a randomized dose-escalation trial comparing 68 Gy and 78 Gy agreed to participate in an additional part of the trial that evaluated SF. Results: At baseline 28% of patients had erectile dysfunction (ED). After 1 year, 27% of the pretreatment potent patients had developed ED. After 2 years this percentage had increased to 36%. After 3 years it almost stabilized at 38%. Satisfaction with sexual life was significantly correlated with ED. After 2 years one third of the pre-treatment potent patients still had considerable to very much sexual desire and found sex (very) important. No significant differences were found between the two dose-arms. Potency aids were used on a regular base by 14% of the patients. Conclusion: By taking adjuvant hormonal therapy (HT), HT during follow-up and potency aids into account, we found a lower percentage of ED after 3D-CRT than reported in previous prospective studies. A large group of patients still had sexual desire, considered sex important and 14% used potency aids after 3D-CRT.

  3. Outcomes of High-Dose-Rate Interstitial Brachytherapy in the Treatment of Locally Advanced Cervical Cancer: Long-term Results

    SciTech Connect

    Pinn-Bingham, Melva; Puthawala, Ajmel A.; Syed, A.M. Nisar; Sharma, Anil; DiSaia, Philip; Berman, Michael; Tewari, Krishnansu S.; Randall-Whitis, Leslie; Mahmood, Usama; Ramsinghani, Nilam; Kuo, Jeffrey; Chen, Wen-Pin; McLaren, Christine E.

    2013-03-01

    Purpose: The purpose of this study was to determine locoregional control (LRC), disease-free survival (DFS), and toxicity of high-dose-rate interstitial brachytherapy (HDR-ISBT) in the treatment of locally advanced cervical cancer. Methods and Materials: Between March 1996 and May 2009, 116 patients with cervical cancer were treated. Of these, 106 (91%) patients had advanced disease (International Federation of Gynecology and Obstetrics stage IIB-IVA). Ten patients had stage IB, 48 had stage II, 51 had stage III, and 7 had stage IVA disease. All patients were treated with a combination of external beam radiation therapy (EBRT) to the pelvis (5040 cGy) and 2 applications of HDR-ISBT to a dose of 3600 cGy to the implanted volume. Sixty-one percent of patients also received interstitial hyperthermia, and 94 (81%) patients received chemotherapy. Results: Clinical LRC was achieved in 99 (85.3%) patients. Three-year DFS rates were 59%, 67%, 71%, and 57% for patients with stage IB, II, III, and IVA disease, respectively. The 5-year DFS and overall survival rates for the entire group were 60% and 44%, respectively. Acute and late toxicities were within acceptable limits. Conclusions: Locally advanced cervical cancer patients for whom intracavitary BT is unsuitable can achieve excellent LRC and OS with a combination of EBRT and HDR-ISBT.

  4. Long-term outcomes from dose-escalated image-guided intensity-modulated radiotherapy with androgen deprivation: encouraging results for intermediate- and high-risk prostate cancer.

    PubMed

    Wilcox, Shea W; Aherne, Noel J; Benjamin, Linus C; Wu, Bosco; de Campos Silva, Thomaz; McLachlan, Craig S; McKay, Michael J; Last, Andrew J; Shakespeare, Thomas P

    2014-01-01

    Dose-escalated (DE) radiotherapy in the setting of localized prostate cancer has been shown to improve biochemical disease-free survival (bDFS) in several studies. In the same group of patients, androgen deprivation therapy (ADT) has been shown to confer a survival benefit when combined with radiotherapy doses of up to 70 Gy; however, there is currently little long-term data on patients who have received high-dose intensity-modulated radiotherapy (IMRT) with ADT. We report the long-term outcomes in a large cohort of patients treated with the combination of DE image-guided IMRT (IG-IMRT) and ADT. Patients with localized prostate cancer were identified from a centralized database across an integrated cancer center. All patients received DE IG-IMRT, combined with ADT, and had a minimum follow up of 12 months post-radiotherapy. All relapse and toxicity data were collected prospectively. Actuarial bDFS, metastasis-free survival, prostate cancer-specific survival, and multivariate analyses were calculated using the SPSS v20.0 statistical package. Seven hundred and eighty-two eligible patients were identified with a median follow up of 46 months. Overall, 4.3% of patients relapsed, 2.0% developed distant metastases, and 0.6% died from metastatic prostate cancer. At 5-years, bDFS was 88%, metastasis-free survival was 95%, and prostate cancer-specific survival was 98%. Five-year grade 2 genitourinary and gastrointestinal toxicity was 2.1% and 3.4%, respectively. No grade 3 or 4 late toxicities were reported. Pretreatment prostate specific antigen (P=0.001) and Gleason score (P=0.03) were significant in predicting biochemical failure on multivariate analysis. There is a high probability of tumor control with DE IG-IMRT combined with androgen deprivation, and this is a technique with a low probability of significant late toxicity. Our long term results corroborate the safety and efficacy of treating with IG-IMRT to high doses and compares favorably with published series for

  5. Accelerated partial breast irradiation in the elderly: 5-year results of high-dose rate multi-catheter brachytherapy

    PubMed Central

    2014-01-01

    Objective To evaluate clinical outcome after accelerated partial breast irradiation (APBI) in the elderly after high-dose-rate interstitial multi-catheter brachytherapy (HIBT). Methods and materials Between 2005 and 2013, 70 patients underwent APBI using HIBT. Catheter implant was performed intra or post-operatively (referred patients) after lumpectomy and axillary sentinel lymph node dissection. Once the pathological results confirmed the indication of APBI, planification CT-scan was performed to deliver 34 Gy/10f/5d or 32 Gy/8f/4d. Dose-volume adaptation was manually achieved (graphical optimization). Dosimetric results and clinical outcome were retrospectively analyzed. Physician cosmetic evaluation was reported. Results With a median follow-up of 60.9 months [4.6 – 90.1], median age was 80.7 years [62 – 93.1]. Regarding APBI ASTRO criteria, 61.4%, 18.6% and 20% were classified as suitable, cautionary and non-suitable respectively. Axillary sentinel lymph node dissection was performed in 94.3%; 8 pts (11.5%) presented an axillary involvement. A median dose of 34 Gy [32 – 35] in 8 to 10 fractions was delivered. Median CTV was 75.2 cc [16.9 – 210], median D90 EQD2 was 43.3 Gy [35 – 72.6] and median DHI was 0.54 [0.19 – 0.74]. One patient experienced ipsilateral recurrence (5-year local free recurrence rate: 97.6%. Five-year specific and overall survival rates were 97.9% and 93.2% respectively. Thirty-four patients (48%) presented 47 late complications classified grade 1 (80.8%) and grade 2 (19.2%) with no grade ≥ 3. Cosmetic results were considered excellent/good for 67 pts (95.7%). Conclusion APBI using HIBT and respecting strict rules of implantation and planification, represents a smart alternative between no post-operative irradiation and whole breast irradiation delivered over 6 consecutive weeks. PMID:24886680

  6. Photospheric Magnetic Field Properties of Flaring vs. Flare-Quiet Active Regions I: Data, General Approach, and Statistical Results

    NASA Astrophysics Data System (ADS)

    Leka, K. D.; Barnes, G.

    2003-05-01

    Photospheric vector magnetic field data from the U. Hawai`i Imaging Vector Magnetograph are examined for pre-event signatures unique to solar energetic phenomena. Parameters are constructed from B(x,y) to describe (for example) the distributions of the field, spatial gradients of the field, vertical current, current helicity, ''twist'' parameter α and magnetic shear angles. A quantitative statistical approach employing discriminant analysis and Hotelling's T2-test is applied to the magnitude and temporal evolution of parameters from 24 flare-event and flare-quiet epochs from seven active regions. We demonstrate that (1) when requiring a flare-unique signature, numerous candidate parameters are nullified by considering flare-quiet epochs, (2) a more robust method exists for estimating error rates than conventional ''truth tables'', (3) flaring and flare-quiet populations do not necessarily have low error rates for classification even when statistically distinguishable, and that (4) simultaneous consideration of a large number of variables is required to produce acceptable error rates. That is, when the parameters are considered individually, they show little ability to differentiate between the two populations; multi-variable combinations can discriminate the populations and/or result in perfect classification tables. In lieu of constructing a single all-variable discriminant function to quantify the flare-predictive power of the parameters considered, we devise a method whereby all permutations of the four-variable discriminant functions are ranked by Hotelling's T2. We present those parameters (e.g. the temporal increase of the kurtosis of the spatial distribution of the vertical current density) which consistently appear in the best combinations, indicating that they may play an important role in defining a pre-event photospheric state. While no single combination is clearly the best discriminator, we demonstrate here the requisite approach: include flare

  7. Comparison of the effects of different statins and doses on lipid levels in patients with diabetes: results from VOYAGER.

    PubMed

    Karlson, B W; Barter, P J; Palmer, M K; Lundman, P; Nicholls, S J

    2012-09-01

    Diabetes mellitus is a well-known risk factor for cardiovascular disease, and brings an increased risk of vascular events and a higher mortality rate. Treatment guidelines recommend statins in patients with diabetes, with low-density lipoprotein cholesterol (LDL-C) targets of 100 mg dl(-1) (∼2.5 mmol l(-1)), and 80 (∼2.0 mmol l(-1)) or 70 mg dl(-1) (∼1.8 mmol l(-1)) in especially high-risk patients. The current study used the VOYAGER (an indiVidual patient data-meta-analysis Of statin therapY in At risk Groups: Effects of Rosuvastatin, atorvastatin, and simvastatin) database to characterise effects of rosuvastatin, atorvastatin and simvastatin in different doses on lipid levels in diabetes patients. The VOYAGER database included individual patient data from 37 studies involving comparisons of rosuvastatin with either atorvastatin or simvastatin. Of the 32 258 patients included, 8859 (27.5%) had diabetes. Rosuvastatin appeared to be the most efficacious of the three statins, both for lowering LDL-C and for reaching a target level of <70 mg dl(-1) for LDL-C. It was also more effective than atorvastatin at raising high-density lipoprotein cholesterol in the diabetes population. These results are consistent with the overall VOYAGER results. This meta-analysis of 8859 patients with diabetes mellitus shows favourable effects on lipids with the three statins studied, in line with results for the overall VOYAGER population. The importance of using an effective statin at an effective dose to reach treatment goals for such high-risk patients is evident. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Assessing Fun Items' Effectiveness in Increasing Learning of College Introductory Statistics Students: Results of a Randomized Experiment

    ERIC Educational Resources Information Center

    Lesser, Lawrence M.; Pearl, Dennis K.; Weber, John J., III

    2016-01-01

    There has been a recent emergence of scholarship on the use of fun in the college statistics classroom, with at least 20 modalities identified. While there have been randomized experiments that suggest that fun can enhance student achievement or attitudes in statistics, these studies have generally been limited to one particular fun modality or…

  9. Assessing Fun Items' Effectiveness in Increasing Learning of College Introductory Statistics Students: Results of a Randomized Experiment

    ERIC Educational Resources Information Center

    Lesser, Lawrence M.; Pearl, Dennis K.; Weber, John J., III

    2016-01-01

    There has been a recent emergence of scholarship on the use of fun in the college statistics classroom, with at least 20 modalities identified. While there have been randomized experiments that suggest that fun can enhance student achievement or attitudes in statistics, these studies have generally been limited to one particular fun modality or…

  10. PHA-stimulated immune-responsiveness in mercury-dosed zebra finches does not match results from environmentally exposed songbirds.

    PubMed

    Caudill, Mitchell T; Spear, Eliza L; Varian-Ramos, Claire W; Cristol, Daniel A

    2015-04-01

    Dietary mercury exposure is associated with suppressed immune responsiveness in birds. This study examined the immune-responsiveness of domestic zebra finches (Taeniopygia guttata) experimentally exposed to mercury through their diet. We used the phytohemagglutinin (PHA) skin-swelling test to assay the effect of two modes of mercury exposure. Some finches received exposure to mercury only after reaching sexual maturity, while others were maintained on a mercury-dosed diet throughout life, including development. Each bird received one of five dietary concentrations of methylmercury cysteine (0.0, 0.3, 0.6, 1.2 or 2.4 ppm). In contrast to a study on wild songbirds at a mercury-contaminated site, we detected no relationship between mercury level and immunological response to PHA, regardless of mode of exposure. This result represents the first major difference found by our laboratory between wild birds exposed to environmental mercury and captive birds experimentally exposed to mercury.

  11. Randomized multicenter follow-up trial on the effect of radiotherapy on painful heel spur (plantar fasciitis) comparing two fractionation schedules with uniform total dose: first results after three months' follow-up.

    PubMed

    Niewald, Marcus; Holtmann, Henrik; Prokein, Benjamin; Hautmann, Matthias G; Rösler, Hans-Peter; Graeber, Stefan; Dzierma, Yvonne; Ruebe, Christian; Fleckenstein, Jochen

    2015-08-19

    Our first trial on radiotherapy for painful heel spur published in 2012 comparing the analgesic effect of a standard dose (6 × 1.0 Gy within three weeks) to that of a very low one (6 × 0.1 Gy within three weeks) resulted in a highly significant superiority of the standard dose arm. In the meantime, experimental data have shown that lower single doses in the range of 0.5 - 0.7 Gy might be even more effective than the current standard dose of 1.0 Gy. Therefore, we conducted a second trial comparing the analgesic effect of standard single doses of 1.0 Gy to that of low single doses of 0.5 Gy using uniform total doses of 6 Gy. One hundred twenty-seven patients were randomized to receive radiation therapy either with a total dose of 6.0 Gy applied in 6 fractions of 1.0 Gy twice weekly (standard dose) or with the same total dose applied in 12 fractions of 0.5 Gy three times weekly (experimental dose). In all patients lateral opposing 6MV photon beams were used. The results were measured using Visual analogue scale (VAS), Calcaneodynia score (CS) and SF-12 health survey. The first phase of this trial ended after a three months' follow-up; it will be continued up to 48 weeks. Nine patients had to be excluded after randomization either due to the withdrawal of informed consent to radiotherapy by the patients or radiotherapy with an incorrect dosage. The groups were comparable concerning biographical and disease data. The mean calcaneodynia score (CS) was higher in the experimental group (p = 0.002). After three months' follow-up, we saw a very favorable pain relief in both arms (decline of VAS score: standard arm 42 points, experimental arm 44 points (n.s.), but we did not notice any statistically significant difference between the arms neither concerning the pain parameters nor the quality of life parameters. No relevant acute side effects were recorded. Favorable laboratory results could not be translated into an enhanced pain relief in our patients. This

  12. Exposure to low doses (20 cGy) of Hze results in spatial memory impairment in rats.

    NASA Astrophysics Data System (ADS)

    Britten, Richard; Johnson, Angela; Davis, Leslie; Green-Mitchell, Shamina; Chabriol, Olivia; Sanford, Larry; Drake, Richard

    INTRODUCTION. Current models predict that the astronauts on a mission to a deep space destination, such as Mars, will be exposed to 25 cGy of Galactic cosmic radiation (GCR). The long-term consequence of exposure to such doses is largely unknown, but given that 1.3 Gy of X-rays has been reported to lead to long-term cognitive deficits (Shore et al, 1976) and that CGR have an RBE of 2-5, it is likely that the predicted 25 cGy of GCR will lead to defects in the cognitive ability of the astronauts during and after the mission. Our studies are designed to help define the GCR dose that will lead to defects in complex working memory, and also to elucidate the mechanisms whereby hadronic radiation diminishes neurocognitive function. The identification of such processes would provide an opportunity for post-mission surveillance, and hopefully will lead to intervention strategies that will ameliorate or attenuate GCR-induced neurocognitive deficits. MATERIALS METHODS. Four-week old male Wistar rats were exposed to either X-rays or 1 GeV 56Fe. At three or six months post exposure the performance of the rats in the Barnes' Maze (Spatial memory) was established. The duration and frequency of REM sleep was also monitored to determine if the neurocognitive deficits arose due to reduced memory consolidation as a result of diminished REM sleep. We used a novel, but maturing technique, called MALDI-MS imaging (or MALDI-MSI), to identify specific regions of the brain where the neuroproteome differs in rats that have developed spatial memory impairments. RESULTS. 11.5 Gy of X-rays led to reduced performance in the Barnes's maze. In contrast, exposure to 20 cGy of Hze (1 GeV 56Fe) resulted in a significant impairment of spatial memory performance as measured in the Barnes' Maze, which was manifested by an increase in relative escape latency REL over a 5 day testing period. Such an increase in REL could arise from the rats becoming less able, or perhaps less willing, to locate the

  13. High-Dose-Rate Rotte 'Y' Applicator Brachytherapy for Definitive Treatment of Medically Inoperable Endometrial Cancer: 10-Year Results

    SciTech Connect

    Coon, Devin; Beriwal, Sushil Heron, Dwight E.; Kelley, Joseph L.; Edwards, Robert P.; Sukumvanich, Paniti; Zorn, Kristin K.; Krivak, Thomas C.

    2008-07-01

    Purpose: To assess the intermediate clinical outcomes of medically inoperable patients with endometrial cancer treated with definitive Rotte 'Y' applicator high-dose-rate brachytherapy (HDRB) over a 10-year period. Methods and Materials: Forty-nine inoperable patients were treated with HDRB from 1997 to 2007. Forty three (84%) were markedly obese (body mass index >35 kg/m{sup 2}). Thirty-one patients (63.3%) underwent two-dimensional treatment planning, whereas 18 patients (36.7%) underwent three-dimensional treatment planning. Thirty five of the patients (71.4%) were first treated with external beam radiotherapy (EBRT). For patients receiving EBRT in addition to HDRB, the median Y-applicator dose was 20 Gy in 5 fractions; for patients receiving HDRB alone it was 35 Gy in 5 fractions. All patients received two Y-applicator treatments per day. Results: Median follow-up time for all patients was 33 months. Acute HDRB toxicities were limited to Grade 1 and 2 occurring in 5 patients. One patient had a myocardial infarction. Four patients had late Grade 2 or 3 toxicity. Three patients had local recurrence (median time to recurrence, 16 months). The 3- and 5-year actuarial cause-specific survival rates were 93% and 87%, respectively; the overall survival rate was 83% and 42%, respectively, at 3 and 5 years. Conclusions: Twice-daily HDRB using a Y-applicator is a well-tolerated and efficacious regimen for the definitive treatment of medically inoperable patients with early-stage endometrial cancer. The recent incorporation of three-dimensional treatment planning has the potential to further decrease treatment morbidities.

  14. Results of a safety trial on single-dose treatments with 400 mcg/kg of ivermectin in bancroftian filariasis.

    PubMed

    Cartel, J L; Moulia-Pelat, J P; Glaziou, P; Nguyen, L N; Chanteau, S; Roux, J F

    1992-12-01

    Two groups of Polynesian Wuchereria bancrofti carriers, 17 females aged 21 to 84 years and 20 males aged 26 to 57 years, in whom microfilaraemia ranged from 1 to 10,121 mf/ml and from 1 to 6,484 mf/ml, respectively, were given a supervised singledose treatment with 400 mcg/kg of ivermectin. Carriers were examined and questioned regarding their experience of adverse reactions, which were graded 0 to 3 according to severity, at 6, 12 and 24 hours and at 4 days after treatment. Biological examinations which included determination of microfilaraemia, complete blood count, liver function tests and assessment of creatinine and urea levels were performed at 4 days before and 4 days after treatment. Adverse reactions were observed in 65% of female and in 70% of male carriers; they were of grade > or = 2 in 35% of carriers in both groups. None as considered serious; they all disappeared in 24-48 hours. The main symptoms were headache, fever > or = 37.5 degrees C and myalgia in females. One male vomited 3 hours after treatment; as a result the drug was not ingested and no decrease of microfilaraemia was noted. Twelve days afterwards, he was given a second 400 mcg/kg dose, he experienced again a grade 1 reaction and his microfilaraemia fell to zero. The 37 carriers in the present study were matched with 37 other Polynesian carriers treated with a 100 mcg/kg single dose of ivermectin in previous trials for pretreatment mf density and sex: no significant difference could be found in adverse reactions between the 2 treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Effects of age, gender and statin dose on lipid levels: Results from the VOYAGER meta-analysis database.

    PubMed

    Karlson, Björn W; Palmer, Michael K; Nicholls, Stephen J; Barter, Philip J; Lundman, Pia

    2017-10-01

    The effectiveness of statins in the treatment of dyslipidaemia and reduction of cardiovascular risk is well established. However, the association of statin-mediated lipid effects with age and gender is unclear. This study aimed to determine whether age and gender are associated with statin-mediated changes in low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and non-HDL-C. Individual patient data (n = 32,258) were obtained from VOYAGER. Least-squares mean percentage change from baseline in LDL-C, non-HDL-C and HDL-C with atorvastatin 10-80 mg, rosuvastatin 5-40 mg or simvastatin 10-80 mg was estimated in women aged <70 years, women aged ≥70 years, men aged <70 years and men aged ≥70 years. All statins and doses gave significant dose-dependent reductions in LDL-C and non-HDL-C, and increases in HDL-C, in all four patient groups. A 2.1% greater reduction in LDL-C was observed in women, compared with men (p < 0.0001). Patients aged ≥70 years experienced a 2.7% greater reduction in LDL-C compared with younger patients (p < 0.0001). Similar results were also observed for statin-mediated changes in non-HDL-C. Men experienced a significantly greater increase in HDL-C than women, and patients aged ≥70 years achieved a significantly greater increase than younger patients (both p = 0.001). While statins improve the lipid profile in all gender and age groups analysed, the improvements are greater in women than in men and in those aged ≥70 years compared with those aged <70 years. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Atmospheric transport and deposition of radionuclides released after the Fukushima Dai-chi accident and resulting effective dose

    NASA Astrophysics Data System (ADS)

    Marzo, Giuseppe A.

    2014-09-01

    On 11 March 2011 an earthquake off the Pacific coast of the Fukushima prefecture generated a tsunami that hit Fukushima Dai-ichi and Fukushima Da-ini Nuclear Power Plants. From 12 March a significant amount of radioactive material was released into the atmosphere and dispersed worldwide. Among the most abundant radioactive species released were iodine and cesium isotopes. By means of an atmospheric dispersion Lagrangian code and publicly available meteorological data, the atmospheric dispersion of 131I, 134Cs, and 137Cs have been simulated for three months after the event with a spatial resolution of 0.5° × 0.5° globally. The simulation has been validated by comparison to publicly available measurements collected in 206 locations worldwide. Sensitivity analysis shows that release height of the radionuclides, wet deposition velocity, and source term are the parameters with the most impact on the simulation results. The simulation shows that the radioactive plume, consisting of about 200 PBq by adding contributions from 131I, 134Cs, and 137Cs, has been transported over the entire northern hemisphere depositing up to 1.2 MBq m-2 nearby the NPPs to less than 20 Bq m-2 in Europe. The consequent effective dose to the population over a 50-year period, calculated by considering both external and internal pathways of exposure, is found to be about 40 mSv in the surroundings of Fukushima Dai-ichi, while other countries in the northern hemisphere experienced doses several orders of magnitude lower suggesting a small impact on the population health elsewhere.

  17. Extended Statistical Short-Range Guidance for Peak Wind Speed Analyses at the Shuttle Landing Facility: Phase II Results

    NASA Technical Reports Server (NTRS)

    Lambert, Winifred C.

    2003-01-01

    This report describes the results from Phase II of the AMU's Short-Range Statistical Forecasting task for peak winds at the Shuttle Landing Facility (SLF). The peak wind speeds are an important forecast element for the Space Shuttle and Expendable Launch Vehicle programs. The 45th Weather Squadron and the Spaceflight Meteorology Group indicate that peak winds are challenging to forecast. The Applied Meteorology Unit was tasked to develop tools that aid in short-range forecasts of peak winds at tower sites of operational interest. A seven year record of wind tower data was used in the analysis. Hourly and directional climatologies by tower and month were developed to determine the seasonal behavior of the average and peak winds. Probability density functions (PDF) of peak wind speed were calculated to determine the distribution of peak speed with average speed. These provide forecasters with a means of determining the probability of meeting or exceeding a certain peak wind given an observed or forecast average speed. A PC-based Graphical User Interface (GUI) tool was created to display the data quickly.

  18. Impact of coronal mass ejections on the Earth's thermosphere and geoeffectiveness observed by ACE and GRACE: Statistical results

    NASA Astrophysics Data System (ADS)

    Krauss, Sandro; Temmer, Manuela; Veronig, Astrid; Baur, Oliver

    2016-04-01

    For the period July 2003 to August 2010, the interplanetary coronal mass ejection (ICME) catalogue maintained by Richardson and Cane lists 106 Earth-directed events, which have been measured in situ by plasma and field instruments on board the ACE satellite. We present a statistical investigation of the Earth's thermospheric neutral density response by means of accelerometer measurements collected by the Gravity Recovery And Climate Experiment (GRACE) satellites, which are available for 104 ICMEs in the data set. We relate the thermospheric density increase to various geomagnetic indices (e.g. Dst, AE, Kp, a-indices, ...) and characteristic ICME parameters (impact speed, southward magnetic field strength Bz). We find high correlations between the ICME Bz and thermospheric density enhancements as well as with most of the geomagnetic indices. Separating the response for the shock-sheath region and the magnetic structure of the ICME, we find for instance that the Dst and SYM-H indices reveal a tighter relation to the Bz minimum in the magnetic structure of the ICME, whereas the polar cap indices show higher correlations with the Bz minimum in the shock-sheath region. These results are expected to further stimulate progress in space weather understanding and applications regarding satellite operations.

  19. [Prevention of topic toxicity of BCG with single-dose prulifloxacin. Preliminary results of a randomized pilot study].

    PubMed

    Serretta, Vincenzo; Ruggirello, Antonina; Giaimo, Rosellina; Sommatino, Francesco; Billone, Valentina; Allegro, Rosalinda; Melloni, Darvinio

    2010-01-01

    Toxicity is a major problem for patients undergoing intravesical therapy with Bacillus Calmette-Guérin (BCG) for the conservative management of intermediate or high-risk non-muscle invasive bladder cancer (NMI-BC). A prospective pilot trial was designed to evaluate the adoption of a single dose of prulifloxacin to prevent the toxicity of BCG. Treatment tolerability and its possible influence on BCG efficacy have been analyzed. The study was designed to evaluate the action of prulifloxacin in patients with intermediate or high-risk NMI-BC, undergoing 6-week induction cycle of BCG. Main exclusion criteria were previous intravesical therapy, urinary infection and any other factor that could influence tolerability to BCG intravesical immunotherapy. The patients were randomized to receive BCG alone versus BCG plus prulifloxacin. BCG toxicity and local tolerability were evaluated by self-administered EORTC QLQ-BLS24 questionnaire, and BCG adverse events (AEs) were classified according a four-class classification. The toxicity and tolerability evaluations were performed at baseline, one week after every instillation and one week and one month after the last instillation. Cystoscopy and cytology were performed 3-monthly. Recurrence and progression were recorded. The study included 43 patients receiving 258 instillations of BCG. The patients were randomized to receive BCG alone (Arm A: 132 instillations in 22 patients) versus BCG plus prulifloxacin given as a single oral dose (600 mg) 6 hours after the instillation. An advantage in favor of prulifloxacin prophylaxis emerged, according to EORTC QLQ-BLS24, in overall incidence of nocturnal micturitions (56% vs 28.6%; p=0.001), insomnia (40% vs 14.3%; p=0.002), urgency (70% vs 42.6%; p=0.05), incontinence (44% vs 12.7%; p=0.01) and bothersome events due to intravesical therapy (84% vs 63.5%; p=0.02). Systemic class IIB and III adverse events occurred in only 14.2% and 3.5% of the patients, respectively. No class IV AE was

  20. Hodgkin's disease in children: Treatment with MOPP and low-dose, extended field irradiation without laparotomy. Late results and toxicity

    SciTech Connect

    Jenkin, D.; Doyle, J.; Berry, M.; Blanchette, V.; Chan, H.; Doherty, M.; Freedman, M.; Greenberg, M.; Panzarella, T.; Saunders, F. )

    1990-01-01

    The 10 year results of a trial of bimodal treatment of Hodgkin's disease in children with 6 cycles of MOPP and low-dose extended field irradiation, without staging laparotomy, were for 57 children in all stages as follows: survival 85%, relapse-free survival 80%, and survival-free of second relapse 86%. There were three fatal toxic events, two due to viral infection and one to a second malignant tumor (NHL). Three other patients developed a second malignant tumour, and one developed a thyroid adenoma. No patient developed acute leukemia. These results are compared with the results of treatment of surgically staged children by extended field irradiation alone, with bimodal treatment reserved for relapse or advanced disease at diagnosis. Initial bimodal treatment improved the overall 10 year survival free from a second relapse rate by 20% (86% vs. 66%). No major difference in treatment toxicity between these two groups has emerged during the first 10 years of follow-up. We conclude that, except for favourable CS-1 presentations, children with Hodgkin's disease confined to the lymphatic system should be given bimodal treatment, but that the least morbid effective combination remains to be determined.

  1. Prevalence of Hyperthyroidism Following Exposure During Childhood or Adolescence to Radioiodines from the Chornobyl Nuclear Accident: Dose-Response Results from the Ukrainian-American Cohort Study

    PubMed Central

    Hatch, M.; Furukawa, K.; Brenner, A.; Olinjyk, V.; Ron, E.; Zablotska, L.; Terekhova, G.; McConnell, R.; Markov, V.; Shpak, V.; Ostroumova, E.; Bouville, A.; Tronko, M.

    2013-01-01

    Relatively few data are available on the prevalence of hyperthyroidism (TSH concentrations of < 0.3 mIU/L, with normal or elevated concentrations of free T4) in individuals exposed to radioiodines at low levels. The accident at the Chornobyl (Chernobyl) nuclear plant in Ukraine on April 26, 1986 exposed large numbers of residents to radioactive fallout, principally to iodine-131 (I-131) (mean and median doses = 0.6 Gray (Gy) and 0.2 Gy). We investigated the relationship of I-131 and prevalent hyperthyroidism among 11,853 individuals exposed as children or adolescents in Ukraine who underwent an in-depth, standardized thyroid gland screening examination 12–14 years later. Radioactivity measurements taken shortly after the accident were available for all subjects and were used to estimate individual thyroid doses. We identified 76 cases of hyperthyroidism (11 overt, 65 subclinical). Using logistic regression, we tested a variety of continuous risk models and conducted categorical analyses for all subjects combined and for females (53 cases, n=5,767) and males (23 cases, n=6,086) separately, but found no convincing evidence of a dose response relationship between I-131 and hyperthyroidism. There was some suggestion of elevated risk among females in an analysis based on a dichotomous dose model with a threshold of 0.5 Gy chosen empirically (OR=1.86, P=0.06), but the statistical significance level was reduced (P=0.13) in a formal analysis with an estimated threshold. In summary, after a thorough exploration of the data, we found no statistically significant dose response relationship between individual I-131 thyroid doses and prevalent hyperthyroidism. PMID:21128800

  2. Estimating Optimal Dose of Twice-Weekly Gemcitabine for Concurrent Chemoradiotherapy in Unresectable Pancreatic Carcinoma: Mature Results of GEMRT-01 Phase I Trial

    SciTech Connect

    Girard, Nicolas; Mornex, Francoise; Bossard, Nadine; Ychou, Marc; Chauffert, Bruno; Wautot, Virginie

    2010-08-01

    Purpose: To accurately determine the maximal tolerated dose, feasibility, and antitumor activity of concurrent chemoradiotherapy including twice-weekly gemcitabine in patients with unresectable pancreatic adenocarcinoma. Methods and Materials: Eligible patients with histologically proven adenocarcinoma of the pancreas were included in this Phase I trial. Radiotherapy was delivered to a total dose of 50 Gy. Concurrent chemotherapy with twice-weekly gemcitabine was administered during the 5 weeks of radiotherapy, from an initial dose of 30 mg/m{sup 2}. The gemcitabine doses were escalated in 10-mg/m{sup 2} increments in a three-plus-three design, until dose-limiting toxicities were observed. Results: A total of 35 patients were included in the trial. The feasibility of chemoradiotherapy was high, because all the patients received the planned total radiation dose, and 26 patients (74%) received {>=}70% of the planned chemotherapy dose. The mean total delivered dose of gemcitabine was 417 mg/m{sup 2} (i.e., 77% of the prescribed dose). The maximal tolerated dose of twice-weekly gemcitabine was 70 mg/m{sup 2}. Of the 35 patients, 13 had a partial response (37%) and 21 had stable disease (60%). Overall, the median survival and the 6-, 12-, and 18-month survival rates were 10.6 months and 82%, 31%, and 11%, respectively. Survival was significantly longer in patients with an initial performance status of 0 or 1 (p = .004). Conclusion: Our mature data have indicated that gemcitabine doses can be increased {<=}70 mg/m{sup 2}, when delivered twice-weekly with concurrent radiotherapy. This combination shows promises to achieve better recurrence-free and overall survival. These results will serve as a basis for further implementation of the multimodal treatment of locally advanced pancreatic carcinoma.

  3. Changes in heparin dose response slope during cardiac surgery: possible result in inaccuracy in predicting heparin bolus dose requirement to achieve target ACT.

    PubMed

    Ichikawa, Junko; Mori, Tetsu; Kodaka, Mitsuharu; Nishiyama, Keiko; Ozaki, Makoto; Komori, Makiko

    2017-09-01

    The substantial interpatient variability in heparin requirement has led to the use of a heparin dose response (HDR) technique. The accuracy of Hepcon-based heparin administration in achieving a target activated clotting time (ACT) using an HDR slope remains controversial. We prospectively studied 86 adult patients scheduled for cardiac surgery requiring cardiopulmonary bypass. The total dose of calculated heparin required for patient and pump priming was administered simultaneously to achieve a target ACT of 450 s for HDR on the Hepcon HMS system. Blood samples were obtained after the induction of anesthesia, at 3 min after heparin administration and after the initiation of CPB to measure kaolin ACT, HDR slope, whole-blood heparin concentration based on the HDR slope and anti-Xa heparin concentration, antithrombin and complete blood count. The target ACT of 450 s was not achieved in 68.6% of patients. Compared with patients who achieved the target ACT, those who failed to achieve their target ACT had a significantly higher platelet count at baseline. Correlation between the HDR slope and heparin sensitivity was poor. Projected heparin concentration and anti-Xa heparin concentration are not interchangeable based on the Bland-Altman analysis. It can be hypothesized that the wide discrepancy in HDR slope versus heparin sensitivity may be explained by an inaccurate prediction of the plasma heparin level and/or the change in HDR of individual patients, depending on in vivo factors such as extravascular sequestration of heparin, decreased intrinsic antithrombin activity level and platelet count and/or activity.

  4. Measuring the statistical validity of summary meta-analysis and meta-regression results for use in clinical practice.

    PubMed

    Willis, Brian H; Riley, Richard D

    2017-09-20

    An important question for clinicians appraising a meta-analysis is: are the findings likely to be valid in their own practice-does the reported effect accurately represent the effect that would occur in their own clinical population? To this end we advance the concept of statistical validity-where the parameter being estimated equals the corresponding parameter for a new independent study. Using a simple ('leave-one-out') cross-validation technique, we demonstrate how we may test meta-analysis estimates for statistical validity using a new validation statistic, Vn, and derive its distribution. We compare this with the usual approach of investigating heterogeneity in meta-analyses and demonstrate the link between statistical validity and homogeneity. Using a simulation study, the properties of Vn and the Q statistic are compared for univariate random effects meta-analysis and a tailored meta-regression model, where information from the setting (included as model covariates) is used to calibrate the summary estimate to the setting of application. Their properties are found to be similar when there are 50 studies or more, but for fewer studies Vn has greater power but a higher type 1 error rate than Q. The power and type 1 error rate of Vn are also shown to depend on the within-study variance, between-study variance, study sample size, and the number of studies in the meta-analysis. Finally, we apply Vn to two published meta-analyses and conclude that it usefully augments standard methods when deciding upon the likely validity of summary meta-analysis estimates in clinical practice. © 2017 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. © 2017 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.

  5. WRAITH - A Computer Code for Calculating Internal and External Doses Resulting From An Atmospheric Release of Radioactive Material

    SciTech Connect

    Scherpelz, R. I.; Borst, F. J.; Hoenes, G. R.

    1980-12-01

    WRAITH is a FORTRAN computer code which calculates the doses received by a standard man exposed to an accidental release of radioactive material. The movement of the released material through the atmosphere is calculated using a bivariate straight-line Gaussian distribution model, with Pasquill values for standard deviations. The quantity of material in the released cloud is modified during its transit time to account for radioactive decay and daughter production. External doses due to exposure to the cloud can be calculated using a semi-infinite cloud approximation. In situations where the semi-infinite cloud approximation is not a good one, the external dose can be calculated by a "finite plume" three-dimensional point-kernel numerical integration technique. Internal doses due to acute inhalation are cal.culated using the ICRP Task Group Lung Model and a four-segmented gastro-intestinal tract model. Translocation of the material between body compartments and retention in the body compartments are calculated using multiple exponential retention functions. Internal doses to each organ are calculated as sums of cross-organ doses, with each target organ irradiated by radioactive material in a number of source organs. All doses are calculated in rads, with separate values determined for high-LET and low-LET radiation.

  6. Low-dose-rate brachytherapy for patients with transurethral resection before implantation in prostate cancer. Long-term results

    PubMed Central

    Prada, Pedro J.; Anchuelo, Javier; Blanco, Ana García; Payá, Gema; Cardenal, Juan; Acuña, Enrique; Ferri, María; Vázquez, Andrés; Pacheco, Maite; Sanchez, Jesica

    2016-01-01

    ABSTRACT Objectives We analyzed the long-term oncologic outcome for patients with prostate cancer and transurethral resection who were treated using low-dose-rate (LDR) prostate brachytherapy. Methods and Materials From January 2001 to December 2005, 57 consecutive patients were treated with clinically localized prostate cancer. No patients received external beam radiation. All of them underwent LDR prostate brachytherapy. Biochemical failure was defined according to the “Phoenix consensus”. Patients were stratified as low and intermediate risk based on The Memorial Sloan Kettering group definition. Results The median follow-up time for these 57 patients was 104 months. The overall survival according to Kaplan-Meier estimates was 88% (±6%) at 5 years and 77% (±6%) at 12 years. The 5 and 10 years for failure in tumour-free survival (TFS) was 96% and respectively (±2%), whereas for biochemical control was 94% and respectively (±3%) at 5 and 10 years, 98% (±1%) of patients being free of local recurrence. A patient reported incontinence after treatment (1.7%). The chronic genitourinary complains grade I were 7% and grade II, 10%. At six months 94% of patients reported no change in bowel function. Conclusions The excellent long-term results and low morbidity presented, as well as the many advantages of prostate brachytherapy over other treatments, demonstrates that brachytherapy is an effective treatment for patients with transurethral resection and clinical organ-confined prostate cancer. PMID:27136466

  7. Safety of intravenously applied mistletoe extract - results from a phase I dose escalation study in patients with advanced cancer.

    PubMed

    Huber, Roman; Schlodder, Dietrich; Effertz, Carola; Rieger, Sabine; Tröger, Wilfried

    2017-09-18

    Mistletoe extracts have anti-tumor properties and are approved for subcutaneous use in cancer patients. Data on Intravenous application are limited. An aqueous extract from pine-mistletoe was used to investigate maximum tolerable dose (MTD) and safety of intravenous application. It was infused once weekly for 3 weeks in patients with advanced cancer. Any type of cancer was included; relevant exclusion criteria were concurrent chemo- or radiation therapy. The classical phase I 3 + 3 dose escalation scheme was followed. Predefined dose groups were 200, 400, 700, 1200 and 2000 mg. Maximum planned dose was 2000 mg. With the MTD three more patients should be treated for 9 weeks in order to evaluate intermediate term tolerability. Weekly during the treatment and 1 week later tolerability, clinical status, safety laboratory parameters and adverse events were documented. Twenty-one patients (3 in the dose groups 200, 400, 700 and 1200 mg, respectively, 9 in the dose group 2000 mg) were included. MTD was not reached. Because one dose-limiting toxicity (DLT), an allergic reaction, occurred during infusion of 2000 mg, three more patients had to be included in this dose group and tolerated it, as well as the three patients who received 2000 mg for 9 weeks. Occasionally in the dose group 2000 mg mild to moderate fever occurred. Weekly infusions of 2000 mg of the pine-mistletoe extract were tolerated and can be used in further studies but had a risk for allergic reactions and fever. German Clinical Trials Register (Trial registration number DRKS00005028).

  8. Population pharmacokinetics of piperacillin in the early phase of septic shock: does standard dosing result in therapeutic plasma concentrations?

    PubMed

    Öbrink-Hansen, Kristina; Juul, Rasmus Vestergaard; Storgaard, Merete; Thomsen, Marianne Kragh; Hardlei, Tore Forsingdal; Brock, Birgitte; Kreilgaard, Mads; Gjedsted, Jakob

    2015-11-01

    Antibiotic dosing in septic shock patients poses a challenge for clinicians due to the pharmacokinetic (PK) variability seen in this patient population. Piperacillin-tazobactam is often used for empirical treatment, and initial appropriate dosing is crucial for reducing mortality. Accordingly, we determined the pharmacokinetic profile of piperacillin (4 g) every 8 h, during the third consecutive dosing interval, in 15 patients treated empirically for septic shock. We developed a population pharmacokinetic model to assess empirical dosing and to simulate alternative dosing regimens and modes of administration. Time above the MIC (T>MIC) predicted for each patient was evaluated against clinical breakpoint MIC for Pseudomonas aeruginosa (16 mg/liter). Pharmacokinetic-pharmacodynamic (PK/PD) targets evaluated were 50% fT>4×MIC and 100% fT>MIC. A population PK model was developed using NONMEM, and data were best described by a two-compartment model. Central and intercompartmental clearances were 3.6 liters/h (relative standard error [RSE], 15.7%) and 6.58 liters/h (RSE, 16.4%), respectively, and central and peripheral volumes were 7.3 liters (RSE, 11.8%) and 3.9 liters (RSE, 9.7%), respectively. Piperacillin plasma concentrations varied considerably between patients and were associated with levels of plasma creatinine. Patients with impaired renal function were more likely to achieve predefined PK/PD targets than were patients with preserved or augmented renal function. Simulations of alternative dosing regimens showed that frequent intermittent bolus dosing as well as dosing by extended and continuous infusion increases the probability of attaining therapeutic plasma concentrations. For septic shock patients with preserved or augmented renal function, dose increment or prolonged infusion of the drug needs to be considered. (This study has been registered at ClinicalTrials.gov under registration no. NCT02306928.).

  9. Dose response to vitamin D supplementation in African Americans: results of a 4-arm, randomized, placebo-controlled trial1234

    PubMed Central

    Ng, Kimmie; Scott, Jamil B; Drake, Bettina F; Chan, Andrew T; Hollis, Bruce W; Chandler, Paulette D; Bennett, Gary G; Giovannucci, Edward L; Gonzalez-Suarez, Elizabeth; Meyerhardt, Jeffrey A; Emmons, Karen M; Fuchs, Charles S

    2014-01-01

    Background: Association studies have suggested that lower circulating 25-hydroxyvitamin D [25(OH)D] in African Americans may partially underlie higher rates of cardiovascular disease and cancer in this population. Nonetheless, the relation between vitamin D supplementation and 25(OH)D concentrations in African Americans remains undefined. Objective: Our primary objective was to determine the dose-response relation between vitamin D and plasma 25(OH)D. Design: A total of 328 African Americans in Boston, MA, were enrolled over 3 winters from 2007 to 2010 and randomly assigned to receive a placebo or 1000, 2000, or 4000 IU vitamin D3/d for 3 mo. Subjects completed sociodemographic and dietary questionnaires, and plasma samples were drawn at baseline and 3 and 6 mo. Results: Median plasma 25(OH)D concentrations at baseline were 15.1, 16.2, 13.9, and 15.7 ng/mL for subjects randomly assigned to receive the placebo or 1000, 2000, or 4000 IU/d, respectively (P = 0.63). The median plasma 25(OH)D concentration at 3 mo differed significantly between supplementation arms at 13.7, 29.7, 34.8, and 45.9 ng/mL, respectively (P < 0.001). An estimated 1640 IU vitamin D3/d was needed to raise the plasma 25(OH)D concentration to ≥20 ng/mL in ≥97.5% of participants, whereas a dose of 4000 IU/d was needed to achieve concentrations ≥33 ng/mL in ≥80% of subjects. No significant hypercalcemia was seen in a subset of participants. Conclusions: Within African Americans, an estimated 1640 IU vitamin D3/d was required to achieve concentrations of plasma 25(OH)D recommended by the Institute of Medicine, whereas 4000 IU/d was needed to reach concentrations predicted to reduce cancer and cardiovascular disease risk in prospective observational studies. These results may be helpful for informing future trials of disease prevention. This trial was registered at clinicaltrials.gov as NCT00585637. PMID:24368437

  10. Assessment of the effective dose equivalent for external photon radiation. Volume 1, Calculational results for beam and point source geometries: Final report

    SciTech Connect

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

    1993-02-01

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

  11. Randomized Noninferiority Trial of Reduced High-Dose Volume Versus Standard Volume Radiation Therapy for Muscle-Invasive Bladder Cancer: Results of the BC2001 Trial (CRUK/01/004)

    SciTech Connect

    Huddart, Robert A.; Hall, Emma; Hussain, Syed A.; Jenkins, Peter; Rawlings, Christine; Tremlett, Jean; Crundwell, Malcolm; Adab, Fawzi A.; Sheehan, Denise; Syndikus, Isabel; Hendron, Carey; Lewis, Rebecca; Waters, Rachel; James, Nicholas D.

    2013-10-01

    Purpose: To test whether reducing radiation dose to uninvolved bladder while maintaining dose to the tumor would reduce side effects without impairing local control in the treatment of muscle-invasive bladder cancer. Methods and Materials: In this phase III multicenter trial, 219 patients were randomized to standard whole-bladder radiation therapy (sRT) or reduced high-dose volume radiation therapy (RHDVRT) that aimed to deliver full radiation dose to the tumor and 80% of maximum dose to the uninvolved bladder. Participants were also randomly assigned to receive radiation therapy alone or radiation therapy plus chemotherapy in a partial 2 × 2 factorial design. The primary endpoints for the radiation therapy volume comparison were late toxicity and time to locoregional recurrence (with a noninferiority margin of 10% at 2 years). Results: Overall incidence of late toxicity was less than predicted, with a cumulative 2-year Radiation Therapy Oncology Group grade 3/4 toxicity rate of 13% (95% confidence interval 8%, 20%) and no statistically significant differences between groups. The difference in 2-year locoregional recurrence free rate (RHDVRT − sRT) was 6.4% (95% confidence interval −7.3%, 16.8%) under an intention to treat analysis and 2.6% (−12.8%, 14.6%) in the “per-protocol” population. Conclusions: In this study RHDVRT did not result in a statistically significant reduction in late side effects compared with sRT, and noninferiority of locoregional control could not be concluded formally. However, overall low rates of clinically significant toxicity combined with low rates of invasive bladder cancer relapse confirm that (chemo)radiation therapy is a valid option for the treatment of muscle-invasive bladder cancer.

  12. Effect of background and transport dose on the results of the personal dose equivalent Hp(10) measurements in photon fields obtained during the intercomparison 2013 of the African region.

    PubMed

    Arib, M; Herrati, A; Dari, F; Lounis-Mokrani, Z

    2015-12-01

    As part of the intercomparison on the measurement of personal dose equivalent Hp(10), jointly organised by the International Atomic Energy Agency and the Algerian Secondary Standard Dosimetry Laboratory, for the African region, up to 12 dosemeters were added to the packages of the 28 participants to evaluate the background and transport dose (BGTD), received by the dosemeters before and after their irradiation at the SSDL (environmental irradiations, scanning process at the airports, etc.). Out of the 28 participants, only 17 reported the corresponding BGTD measured values, which lied between 0.03 and 0.8 mSv. The mean measured value of BG was (0.25±0.14) mSv, which is significantly high compared with the lowest dose value used in the intercomparison exercise. The BGTD correction shifted the overall results of the intercomparison from an overestimation of dose (∼8 % before applying BGT dose correction) to an underestimation of dose (-9 % after correction). The measurement protocol and the detailed analysis of the results and applied corrections are discussed in this paper.

  13. Recommendations to the Technical Steering Panel regarding approach for estimating individual radiation doses resulting from releases of radionuclides to the Columbia River

    SciTech Connect

    Napier, B.A.; Brothers, A.J.

    1992-07-01

    At the direction of the Technical Steering Panel (TSP) of the Hanford Environmental Dose Reconstruction (HEDR) Project, Battelle staff have reviewed and analyzed available data regarding possible historical radiation doses to individuals resulting from radionuclide releases to the Columbia River. The objective of this review was to recommend to the TSP the spatial and temporal scope and level of effort on Columbia River work to most effectively extend work performed in Phase I of the project (PNL 1991a, PNL 1991b) to meet the project objectives. A number of options were analyzed. Four stretches of the Columbia River and adjacent Pacific coastal waters were defined and investigated for four time periods. Radiation doses arising from ten potentially major exposure pathways were evaluated for each of the time/location combinations, and several alternative methods were defined for estimating the doses from each pathway. Preliminary cost estimates were also developed for implementing dose estimation activities for each of the possible combinations.

  14. Measuring the statistical validity of summary meta‐analysis and meta‐regression results for use in clinical practice

    PubMed Central

    Riley, Richard D.

    2017-01-01

    An important question for clinicians appraising a meta‐analysis is: are the findings likely to be valid in their own practice—does the reported effect accurately represent the effect that would occur in their own clinical population? To this end we advance the concept of statistical validity—where the parameter being estimated equals the corresponding parameter for a new independent study. Using a simple (‘leave‐one‐out’) cross‐validation technique, we demonstrate how we may test meta‐analysis estimates for statistical validity using a new validation statistic, Vn, and derive its distribution. We compare this with the usual approach of investigating heterogeneity in meta‐analyses and demonstrate the link between statistical validity and homogeneity. Using a simulation study, the properties of Vn and the Q statistic are compared for univariate random effects meta‐analysis and a tailored meta‐regression model, where information from the setting (included as model covariates) is used to calibrate the summary estimate to the setting of application. Their properties are found to be similar when there are 50 studies or more, but for fewer studies Vn has greater power but a higher type 1 error rate than Q. The power and type 1 error rate of Vn are also shown to depend on the within‐study variance, between‐study variance, study sample size, and the number of studies in the meta‐analysis. Finally, we apply Vn to two published meta‐analyses and conclude that it usefully augments standard methods when deciding upon the likely validity of summary meta‐analysis estimates in clinical practice. © 2017 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. PMID:28620945

  15. Dose-response approaches for nuclear receptor-mediated modes of action for liver carcinogenicity: Results of a workshop

    EPA Science Inventory

    A public workshop, organized by a Steering Committee of scientists from government, industry, universities, and research organizations, was held at the National Institute of Environmental Health Sciences (NIEHS) in September, 2010. The workshop explored the dose-response implicat...

  16. Dose-response approaches for nuclear receptor-mediated modes of action for liver carcinogenicity: Results of a workshop

    EPA Science Inventory

    A public workshop, organized by a Steering Committee of scientists from government, industry, universities, and research organizations, was held at the National Institute of Environmental Health Sciences (NIEHS) in September, 2010. The workshop explored the dose-response implicat...

  17. Pharmacodynamics of non-break weekly paclitaxel (Taxol) and pharmacokinetics of Cremophor-EL vehicle: results of a dose-escalation study.

    PubMed

    Briasoulis, Evangelos; Karavasilis, Vasilis; Tzamakou, Eleftheria; Haidou, Constantina; Piperidou, Christina; Pavlidis, Nicholas

    2002-06-01

    We characterized the toxicity and determined the maximum tolerated dose of non-break weekly paclitaxel (Taxol) in chemotherapy-naive cancer patients, and studied pharmacokinetics of the formulation vehicle Cremophor-EL with this schedule. Twenty-three patients with primary refractory solid tumors received weekly paclitaxel at the dose range of 70-200 mg/m2. As dose-limiting toxicity we defined granulocytopenia grade > or =2 causing a treatment delay for more than 2 weeks, or febrile neutropenia or grade >2 organ-specific toxicity. Plasma kinetics of Cremophor-EL were analyzed over the first five courses of treatment. Non-break weekly paclitaxel was feasible at doses up to 110 mg/m2, while granulocytopenia precluded scheduled administration of doses > or =130 mg/m2. Clinically relevant peripheral neurotoxicity tended to occur at around 1500 mg/m2 cumulative dosage at weekly doses > or =110 mg/m2. Detectable Cremophor-EL levels were found in all pre-dose samples, but there was no evidence of accumulation up to the sixth course. Our results, discussed in the light of an overview of published data, suggest that chronic weekly administration of paclitaxel is feasible and with a lack of significant accumulation of Cremophor-EL levels at doses up to 90 mg/m2.

  18. A comparison of dose results from the Clean Air Act Assessment Package-1988, personal computer (CAP88-PC), version 3 to previous versions.

    PubMed

    Rhoads, Kathleen; Snyder, Sandra; Staven, Lissa

    2013-08-01

    Computer software packages approved by the U.S. Environmental Protection Agency (U.S. EPA), including CAP88-PC, are used by U.S. Department of Energy (U.S. DOE) sites to demonstrate compliance with the radionuclide air emission standard under the Clean Air Act. CAP88-PC version 3, was approved by the U.S. EPA in February 2006 for use by U.S. DOE facilities. Version 3 incorporates several major changes that have the potential to affect calculated doses relative to calculations using earlier versions. This analysis examined the types and magnitudes of changes to dose estimates for specific radionuclides calculated using the version 3 software compared with the previous versions. For parent radionuclides and for the total dose from radionuclide chains, total effective dose calculated with version 3 was compared to effective dose equivalent calculated with previous versions. Various comparisons were also performed to determine which of the updates in version 3 accounted for changes in overall dose estimates. CAP88-PC version 3 would produce substantially different results relative to previous versions of the code for a number of radionuclides, including some isotopes that may be present at U.S. DOE facilities, as well as those used for industrial and medical applications. In general, doses for many radionuclides were lower using version 3 but doses for a few key radionuclides increased relative to the previous versions.

  19. A COMPARISON OF DOSE RESULTS FROM THE CLEAN AIR ACT ASSESSMENT PACKAGE-1988, PERSONAL COMPUTER (CAP88-PC), VERSION 3 TO PREVIOUS VERSIONS

    SciTech Connect

    Rhoads, Kathleen; Snyder, Sandra F.; Staven, Lissa H.

    2013-08-01

    EPA-approved computer software packages, including CAP88-PC, are used by Department of Energy sites to demonstrate compliance with the radionuclide air emission standard under the Clean Air Act. The most recent update, CAP88-PC version 3, was approved by EPA in February 2006 for use by Department of Energy facilities. Version 3 incorporates several major changes that have the potential to affect calculated doses relative to calculations using earlier versions. This analysis examined the types and magnitudes of changes to dose estimates for specific radionuclides calculated using the version 3 software compared with the previous versions. Total effective dose calculated with version 3 was compared to effective dose equivalent calculated with previous versions for parent radionuclides and for the total dose from radionuclide chains. Various comparisons were also performed to determine which of the updates in version 3 accounted for changes in overall dose estimates. CAP88-PC version 3 would produce substantially different results relative to previous versions of the code for a number of radionuclides, including some isotopes that may be present at Department of Energy facilities, as well as those used for industrial and medical applications. In general, doses for many radionuclides are lower using version 3 but doses for a few key radionuclides would be higher.

  20. Long term results from a prospective database on high dose rate (HDR) interstitial brachytherapy for primary cervical carcinoma.

    PubMed

    Fallon, Julia; Park, Sang-Jung; Yang, Lisa; Veruttipong, Darlene; Zhang, Mingle; Van, Thanh; Wang, Pin-Chieh; Fekete, Alexandra M; Cambeiro, Mauricio; Kamrava, Mitchell; Steinberg, Michael L; Demanes, D Jeffrey

    2016-10-29

    Present long-term outcomes in primary cervical cancer treated with external beam and high dose rate interstitial brachytherapy. High dose rate (HDR) interstitial (IS) brachytherapy (BT) and external beam (EBRT) were administered from 1992 to 2009 to 315 patients who were unsuitable for intracavitary (IC) BT alone. Histology was 89% squamous cell, 8% adenocarcinoma, and 3% adenosquamous. FIGO stage was I-14%, II-47%, III-34%, and IVA-5%. Median tumor size was 6cm. Lymph node metastases were 26% pelvic and 9.5% para-aortic. Treatment planning was 49% 2D and 51% 3D-CT. The mean doses were central EBRT EQD210 37.3±4.3Gy (sidewall 49.2±3.6Gy) and HDR EQD210 42.3±5.3Gy (nominal 5.4Gy×6 fractions using a mean of 24 catheters and 1 tandem). Total EQD210 mean target dose was 79.5±5.4Gy. Standardized planned dose constraints were ICRU points or D0.1cc bladder 80%, rectum 75% and urethra 90% of the HDR dose per fraction. Morbidity assessment was CTCAEv3. Median and mean follow-up were 50 and 61months (3-234). The 10-year actuarial local control was 87%, regional control 84%, and loco-regional control 77%. Distant metastasis free survival was 66%, cause specific survival 56%, disease free survival 54%, and overall survival 40%. The rates of late grade GU and GI toxicities were 4.8% G3 and 5.4% G4. Template-guided interstitial can be safely performed to successfully deliver high radiation dose to locally advanced cervix cancer and avoid excessive dose and injury to adjacent vital pelvic organs. We achieved high tumor control with low morbidity in patients who were poor candidates for intracavitary brachytherapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Localized Low-Dose Radiotherapy for Follicular Lymphoma: History, Clinical Results, Mechanisms of Action, and Future Outlooks

    SciTech Connect

    Ganem, Gerard; Cartron, Guillaume; Girinsky, Theodore; Haas, Rick L.M.; Cosset, Jean Marc; Solal-Celigny, Philippe

    2010-11-15

    The extreme radiosensitivity of indolent lymphomas was reported in the early years of radiotherapy (RT). The efficacy of low-dose total body irradiation (1.5-2 Gy) was particularly demonstrative. Higher doses were considered appropriate for localized disease. The optimal (or conventional) dose of curative RT derived from the early studies was determined to be 30-35 Gy. Nevertheless, in older series addressing the tumoricidal radiation dose in non-Hodgkin's lymphomas, investigators noted that a significant number of 'nodular' lymphomas were controlled with a dose of <22 Gy for >3 years. The idea of reintroducing localized low-dose radiotherapy (LDRT) for indolent non-Hodgkin's lymphomas came from a clinical observation. The first study showing the high efficacy of LDRT (4 Gy in two fractions of 2 Gy within 3 days) in selected patients with chemoresistant, indolent, non-Hodgkin's lymphomas was published in 1994. Since this first report, at least eight series of patients treated with localized LDRT have been published, showing a 55% complete response rate in irradiated sites, with a median duration of 15-42 months. How LDRT induces lymphoma cell death remains partly unknown. However, some important advances have recently been reported. Localized LDRT induces an apoptosis of follicular lymphoma cells. This apoptotic cell death elicits an immune response mediated by macrophages and dendritic cells. Follicular lymphoma is probably an ideal model to explore these mechanisms. This review also discusses the future of LDRT for follicular lymphoma.

  2. Guideline and preliminary clinical practice results for dose specification and target delineation for postoperative radiotherapy for oral cavity cancer.

    PubMed

    Liu, Shih-Hua; Chao, K S Clifford; Leu, Yi-Shing; Lee, Jehn-Chuan; Liu, Chung-Ji; Huang, Yu-Chuen; Chang, Yi-Fang; Chen, Hong-Wen; Tsai, Jo-Ting; Chen, Yu-Jen

    2015-07-01

    Surgery followed by radiotherapy (RT) is indicated for patients with high-risk oral cavity cancer (OCC). Based on multi-institutional reports, we developed a guideline for postoperative RT for patients with OCC. A multidisciplinary OCC team was recruited to develop a questionnaire concerning details of risk-factor categorization, target delineation, and dose specification. Thirty-one radiation oncologists from 18 institutions completed the questionnaire, and data were subjected to extensive review to establish the guideline by expert meeting. In this study, we also report the results for patients treated in accordance with the guideline at our institution between 2007 and 2011. Forty-one patients received RT compatible with this guideline with a median 26.8-month follow-up. Thirty-two patients (78%) remained disease-free, 6 (15%) developed locoregional recurrence (4 in-field, 1 marginal, and 1 out-field) and 4 (10%) developed distant metastasis. The overall 2-year survival rate was 86.7%. This guideline is promising and should be validated and refined in further clinical practice. © 2014 Wiley Periodicals, Inc.

  3. Temporal and spatial evolution of the solar energetic particle event on 20 January 2005 and resulting radiation doses in aviation

    NASA Astrophysics Data System (ADS)

    Matthiä, D.; Heber, B.; Reitz, G.; Meier, M.; Sihver, L.; Berger, T.; Herbst, K.

    2009-08-01

    The solar energetic particle event on 20 January 2005 was one of the largest ground level events ever observed. Neutron monitor stations in the Antarctic recorded count rate increases of several thousand percent caused by secondary energetic particles, and it took more than 36 h to return to background level. Such huge increases in high energetic solar cosmic radiation on the ground are obviously accompanied by considerable changes in the radiation environment at aviation altitudes. Measurements of 28 neutron monitor stations were used in this work to numerically approximate the primary solar proton spectra during the first 12 h of the event by minimizing the differences between measurements and the results of Monte-Carlo calculated count rate increases. The primary spectrum of solar energetic protons was approximated by a power law in rigidity and a linear angular distribution. The incoming direction of the solar energetic particles was determined and compared to the interplanetary magnetic field direction during the event. The effects on the radiation exposure at altitudes of about 12 km during that time were estimated to range from none at low latitudes up to almost 2 mSv/h for a very short time in the Antarctic region and about 0.1 mSv/h at high latitudes on the Northern Hemisphere. After 12 h, dose rates were still increased by 50% at latitudes above 60° whereas no increases at all occurred at latitudes below 40° during the whole event.

  4. High-dose-rate intraluminal brachytherapy prior to external radiochemotherapy in locally advanced esophageal cancer: preliminary results

    PubMed Central

    Safaei, Afsaneh Maddah; Ghalehtaki, Reza; Khanjani, Nezhat; Farazmand, Borna; Babaei, Mohammad

    2017-01-01

    Purpose Dysphagia is a common initial presentation in locally advanced esophageal cancer and negatively impacts patient quality of life and treatment compliance. To induce fast relief of dysphagia in patients with potentially operable esophageal cancer high-dose-rate (HDR) brachytherapy was applied prior to definitive radiochemotherapy. Material and methods In this single arm phase II clinical trial between 2013 to 2014 twenty patients with locally advanced esophageal cancer (17 squamous cell and 3 adenocarcinoma) were treated with upfront 10 Gy HDR brachytherapy, followed by 50.4 Gy external beam radiotherapy (EBRT) and concurrent chemotherapy with cisplatin/5-fluorouracil. Results Tumor response, as measured by endoscopy and/or computed tomography scan, revealed complete remission in 16 and partial response in 4 patients (overall response rate 100%). Improvement of dysphagia was induced by brachytherapy within a few days and maintained up to the end of treatment in 80% of patients. No differences in either response rate or dysphagia resolution were found between squamous cell and adenocarcinoma histology. The grade 2 and 3 acute pancytopenia or bicytopenia reported in 4 patients, while sub-acute adverse effects with painful ulceration was seen in five patients, occurring after a median of 2 months. A perforation developed in one patient during the procedure of brachytherapy that resolved successfully with immediate surgery. Conclusions Brachytherapy before EBRT was a safe and effective procedure to induce rapid and durable relief from dysphagia, especially when combined with EBRT. PMID:28344601

  5. A Simple Low-dose X-ray CT Simulation from High-dose Scan.

    PubMed

    Zeng, Dong; Huang, Jing; Bian, Zhaoying; Niu, Shanzhou; Zhang, Hua; Feng, Qianjin; Liang, Zhengrong; Ma, Jianhua

    2015-10-01

    Low-dose X-ray computed tomography (CT) simulation from high-dose scan is required in optimizing radiation dose to patients. In this study, we propose a simple low-dose CT simulation strategy in sinogram domain using the raw data from high-dose scan. Specially, a relationship between the incident fluxes of low- and high- dose scans is first determined according to the repeated projection measurements and analysis. Second, the incident flux level of the simulated low-dose scan is generated by properly scaling the incident flux level of high-dose scan via the determined relationship in the first step. Third, the low-dose CT transmission data by energy integrating detection is simulated by adding a statistically independent Poisson noise distribution plus a statistically independent Gaussian noise distribution. Finally, a filtered back-projection (FBP) algorithm is implemented to reconstruct the resultant low-dose CT images. The present low-dose simulation strategy is verified on the simulations and real scans by comparing it with the existing low-dose CT simulation tool. Experimental results demonstrated that the present low-dose CT simulation strategy can generate accurate low-dose CT sinogram data from high-dose scan in terms of qualitative and quantitative measurements.

  6. The Libraries of the National Statistical Offices in the World. Comments on the Results of an Enquiry.

    ERIC Educational Resources Information Center

    Kullmer, Hans K.

    Defined in terms of their institutional role and historical development, national statistical libraries are discussed in the context of present structures, size, personnel situation, technical equipment, financial structure, general and specific activities, areas of specialization, and growth rate, as well as the interlibrary cooperative efforts…

  7. High dose melphalan or intermediate dose melphalan can be well tolerated and result in good response rates in selected elderly patients with myeloma.

    PubMed

    Bishton, M; Gilyead, M; Das Gupta, E; Williams, C; Russell, N H; Byrne, J L

    2007-08-01

    We have used two strategies for treating myeloma patients aged 65-75 years. Those fit enough underwent Cyclophosphamide mobilisation and PBSCT using melphalan 200mg/m(2) (HDM) (n=15, median 67 years). Those less fit were mobilised with G-CSF and received melphalan 70mg/m(2) (IDM) (n=15, median 69 years). Where possible sufficient PBSC were collected so that patients not in CR after their first IDM, underwent a second IDM procedure (n=6). The treatment was well tolerated with zero day+100 TRM. Median cell dose was 4.85x10(6)CD34+cells/kg and 2.7x10(6) in the HDM and IDM groups, respectively. Neutrophil engraftment was faster in the HDM group but despite this there was a trend to earlier discharge in the IDM group (13 days versus 15 days) and lower antibiotic and anti-fungal usage, suggesting better tolerability. Response rates were similar with CRs achieved in 7/15 patients receiving HDM and 9/15 receiving IDM (6 after the first and 3 after the second procedure). Three patients did not undergo a second IDM due to insufficient cells. In the IDM group 11/15 remain alive at a median follow up of 14 months with 5 in CR, whilst in the HDM group 12/15 are alive with 5 in CR at a median follow up of 15.5m. We conclude both approaches have comparable efficacy but that IDM may be better tolerated in an older age group.

  8. Randomized Trial Comparing Conventional-Dose With High-Dose Conformal Radiation Therapy in Early-Stage Adenocarcinoma of the Prostate: Long-Term Results From Proton Radiation Oncology Group/American College of Radiology 95-09

    PubMed Central

    Zietman, Anthony L.; Bae, Kyounghwa; Slater, Jerry D.; Shipley, William U.; Efstathiou, Jason A.; Coen, John J.; Bush, David A.; Lunt, Margie; Spiegel, Daphna Y.; Skowronski, Rafi; Jabola, B. Rodney; Rossi, Carl J.

    2010-01-01

    Purpose To test the hypothesis that increasing radiation dose delivered to men with early-stage prostate cancer improves clinical outcomes. Patients and Methods Men with T1b-T2b prostate cancer and prostate-specific antigen ≤ 15 ng/mL were randomly assigned to a total dose of either 70.2 Gray equivalents (GyE; conventional) or 79.2 GyE (high). No patient received androgen suppression therapy with radiation. Local failure (LF), biochemical failure (BF), and overall survival (OS) were outcomes. Results A total of 393 men were randomly assigned, and median follow-up was 8.9 years. Men receiving high-dose radiation therapy were significantly less likely to have LF, with a hazard ratio of 0.57. The 10-year American Society for Therapeutic Radiology and Oncology BF rates were 32.4% for conventional-dose and 16.7% for high-dose radiation therapy (P < .0001). This difference held when only those with low-risk disease (n = 227; 58% of total) were examined: 28.2% for conventional and 7.1% for high dose (P < .0001). There was a strong trend in the same direction for the intermediate-risk patients (n = 144; 37% of total; 42.1% v 30.4%, P = .06). Eleven percent of patients subsequently required androgen deprivation for recurrence after conventional dose compared with 6% after high dose (P = .047). There remains no difference in OS rates between the treatment arms (78.4% v 83.4%; P = .41). Two percent of patients in both arms experienced late grade ≥ 3 genitourinary toxicity, and 1% of patients in the high-dose arm experienced late grade ≥ 3 GI toxicity. Conclusion This randomized controlled trial shows superior long-term cancer control for men with localized prostate cancer receiving high-dose versus conventional-dose radiation. This was achieved without an increase in grade ≥ 3 late urinary or rectal morbidity. PMID:20124169

  9. SU-E-J-06: Additional Imaging Guidance Dose to Patient Organs Resulting From X-Ray Tubes Used in CyberKnife Image Guidance System

    SciTech Connect

    Sullivan, A; Ding, G

    2015-06-15

    Purpose: The use of image-guided radiation therapy (IGRT) has become increasingly common, but the additional radiation exposure resulting from repeated image guidance procedures raises concerns. Although there are many studies reporting imaging dose from different image guidance devices, imaging dose for the CyberKnife Robotic Radiosurgery System is not available. This study provides estimated organ doses resulting from image guidance procedures on the CyberKnife system. Methods: Commercially available Monte Carlo software, PCXMC, was used to calculate average organ doses resulting from x-ray tubes used in the CyberKnife system. There are seven imaging protocols with kVp ranging from 60 – 120 kV and 15 mAs for treatment sites in the Cranium, Head and Neck, Thorax, and Abdomen. The output of each image protocol was measured at treatment isocenter. For each site and protocol, Adult body sizes ranging from anorexic to extremely obese were simulated since organ dose depends on patient size. Doses for all organs within the imaging field-of-view of each site were calculated for a single image acquisition from both of the orthogonal x-ray tubes. Results: Average organ doses were <1.0 mGy for every treatment site and imaging protocol. For a given organ, dose increases as kV increases or body size decreases. Higher doses are typically reported for skeletal components, such as the skull, ribs, or clavicles, than for softtissue organs. Typical organ doses due to a single exposure are estimated as 0.23 mGy to the brain, 0.29 mGy to the heart, 0.08 mGy to the kidneys, etc., depending on the imaging protocol and site. Conclusion: The organ doses vary with treatment site, imaging protocol and patient size. Although the organ dose from a single image acquisition resulting from two orthogonal beams is generally insignificant, the sum of repeated image acquisitions (>100) could reach 10–20 cGy for a typical treatment fraction.

  10. Initial Results of a Large-scale Statistical Survey of Small-scale UV Bursts with IRIS and SDO

    NASA Astrophysics Data System (ADS)

    Madsen, C. A.; DeLuca, E.

    2016-12-01

    UV bursts are small-scale ( 1 arcsec or less) brightenings observed in the NUV/FUV passbands of the Interface Region Imaging Spectrograph (IRIS). These peculiar phenomena are found exclusively in active regions and exhibit dramatic and defining spectroscopic characteristics. In particular, they present intense broadening and splitting, often in excess of 70 km s-1, in all bright emission lines observable by IRIS. Furthermore, these broadened lines also display strong absorption from cool metallic ions such as Fe II and Ni II which typically populate the chromosphere. These features suggest that bursts are bidirectional plasma flows at transition region temperatures embedded much farther down in the cool chromosphere. To better characterize these phenomena, we have launched a statistical survey encompassing the entire IRIS data catalogue to date and its accompanying data from the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI). We sample a wide variety of IRIS observations of Si IV lines, ranging from large 400-step rasters for large detection rates to short-cadence sit-and-stare observations to provide in-depth time evolution data of individual bursts. Detection is streamlined by a semi-automated method that isolates characteristic burst spectra based on single-Gaussian fit parameters, greatly reducing search times in the vast IRIS catalogue. Our initial results demonstrate that UV bursts tend to appear when active regions are young and actively emerging, preferring to populate poorly developed inversion lines composed of numerous small mixed-polarity regions. Burst occurrence rates peak at 30-70 per hour in young active regions, decreasing as those regions age. We also find dramatic variations in spectral morphology in spatial scans of bursts with many split into distinct, opposing, resolved regions of blueshifts and redshifts. Finally, we find little evidence for coronal counterparts in AIA 171 Å, but we do find that a significant

  11. A stochastic storm surge generator for the German North Sea and the multivariate statistical assessment of the simulation results

    NASA Astrophysics Data System (ADS)

    Wahl, Thomas; Jensen, Jürgen; Mudersbach, Christoph

    2010-05-01

    Storm surges along the German North Sea coastline led to major damages in the past and the risk of inundation is expected to increase in the course of an ongoing climate change. The knowledge of the characteristics of possible storm surges is essential for the performance of integrated risk analyses, e.g. based on the source-pathway-receptor concept. The latter includes the storm surge simulation/analyses (source), modelling of dike/dune breach scenarios (pathway) and the quantification of potential losses (receptor). In subproject 1b of the German joint research project XtremRisK (www.xtremrisk.de), a stochastic storm surge generator for the south-eastern North Sea area is developed. The input data for the multivariate model are high resolution sea level observations from tide gauges during extreme events. Based on 25 parameters (19 sea level parameters and 6 time parameters) observed storm surge hydrographs consisting of three tides are parameterised. Followed by the adaption of common parametric probability distributions and a large number of Monte-Carlo-Simulations, the final reconstruction leads to a set of 100.000 (default) synthetic storm surge events with a one-minute resolution. Such a data set can potentially serve as the basis for a large number of applications. For risk analyses, storm surges with peak water levels exceeding the design water levels are of special interest. The occurrence probabilities of the simulated extreme events are estimated based on multivariate statistics, considering the parameters "peak water level" and "fullness/intensity". In the past, most studies considered only the peak water levels during extreme events, which might not be the most important parameter in any cases. Here, a 2D-Archimedian copula model is used for the estimation of the joint probabilities of the selected parameters, accounting for the structures of dependence overlooking the margins. In coordination with subproject 1a, the results will be used as the input

  12. A new warfarin dosing algorithm including VKORC1 3730 G > A polymorphism: comparison with results obtained by other published algorithms.

    PubMed

    Cini, Michela; Legnani, Cristina; Cosmi, Benilde; Guazzaloca, Giuliana; Valdrè, Lelia; Frascaro, Mirella; Palareti, Gualtiero

    2012-08-01

    Warfarin dosing is affected by clinical and genetic variants, but the contribution of the genotype associated with warfarin resistance in pharmacogenetic algorithms has not been well assessed yet. We developed a new dosing algorithm including polymorphisms associated both with warfarin sensitivity and resistance in the Italian population, and its performance was compared with those of eight previously published algorithms. Clinical and genetic data (CYP2C9*2, CYP2C9*3, VKORC1 -1639 G > A, and VKORC1 3730 G > A) were used to elaborate the new algorithm. Derivation and validation groups comprised 55 (58.2% men, mean age 69 years) and 40 (57.5% men, mean age 70 years) patients, respectively, who were on stable anticoagulation therapy for at least 3 months with different oral anticoagulation therapy (OAT) indications. Performance of the new algorithm, evaluated with mean absolute error (MAE) defined as the absolute value of the difference between observed daily maintenance dose and predicted daily dose, correlation with the observed dose and R(2) value, was comparable with or slightly lower than that obtained using the other algorithms. The new algorithm could correctly assign 53.3%, 50.0%, and 57.1% of patients to the low (≤25 mg/week), intermediate (26-44 mg/week) and high (≥ 45 mg/week) dosing range, respectively. Our data showed a significant increase in predictive accuracy among patients requiring high warfarin dose compared with the other algorithms (ranging from 0% to 28.6%). The algorithm including VKORC1 3730 G > A, associated with warfarin resistance, allowed a more accurate identification of resistant patients who require higher warfarin dosage.

  13. Normal tissue complication probability (NTCP) modelling using spatial dose metrics and machine learning methods for severe acute oral mucositis resulting from head and neck radiotherapy

    PubMed Central

    Dean, Jamie A; Wong, Kee H; Welsh, Liam C; Jones, Ann-Britt; Schick, Ulrike; Newbold, Kate L; Bhide, Shreerang A; Harrington, Kevin J; Nutting, Christopher M; Gulliford, Sarah L

    2016-01-01

    Background and Purpose Severe acute mucositis commonly results from head and neck (chemo)radiotherapy. A predictive model of mucositis could guide clinical decision-making and inform treatment planning. We aimed to generate such a model using spatial dose metrics and machine learning. Material and Methods Predictive models of severe acute mucositis were generated using radiotherapy dose (dose-volume and spatial dose metrics) and clinical data. Penalised logistic regression, support vector classification and random forest classification (RFC) models were generated and compared. Internal validation was performed (with 100-iteration cross-validation), using multiple metrics, including area under the receiver operating characteristic curve (AUC) and calibration slope, to assess performance. Associations between covariates and severe mucositis were explored using the models. Results The dose-volume-based models (standard) performed equally to those incorporating spatial information. Discrimination was similar between models, but the RFCstandard had the best calibration. The mean AUC and calibration slope for this model were 0.71 (s.d.=0.09) and 3.9 (s.d.=2.2), respectively. The volumes of oral cavity receiving intermediate and high doses were associated with severe mucositis. Conclusions The RFCstandard model performance is modest-to-good, but should be improved, and requires external validation. Reducing the volumes of oral cavity receiving intermediate and high doses may reduce mucositis incidence. PMID:27240717

  14. High-Dose-Rate Interstitial Brachytherapy as Monotherapy for Clinically Localized Prostate Cancer: Treatment Evolution and Mature Results

    SciTech Connect

    Zamboglou, Nikolaos; Tselis, Nikolaos; Baltas, Dimos; Buhleier, Thomas; Martin, Thomas; Milickovic, Natasa; Papaioannou, Sokratis; Ackermann, Hanns; Tunn, Ulf W.

    2013-03-01

    Purpose: To report the clinical outcome of high-dose-rate (HDR) interstitial (IRT) brachytherapy (BRT) as sole treatment (monotherapy) for clinically localized prostate cancer. Methods and Materials: Between January 2002 and December 2009, 718 consecutive patients with clinically localized prostate cancer were treated with transrectal ultrasound (TRUS)-guided HDR monotherapy. Three treatment protocols were applied; 141 patients received 38.0 Gy using one implant in 4 fractions of 9.5 Gy with computed tomography-based treatment planning; 351 patients received 38.0 Gy in 4 fractions of 9.5 Gy, using 2 implants (2 weeks apart) and intraoperative TRUS real-time treatment planning; and 226 patients received 34.5 Gy, using 3 single-fraction implants of 11.5 Gy (3 weeks apart) and intraoperative TRUS real-time treatment planning. Biochemical failure was defined according to the Phoenix consensus, and toxicity was evaluated using Common Toxicity Criteria for Adverse Events version 3. Results: The median follow-up time was 52.8 months. The 36-, 60-, and 96-month biochemical control and metastasis-free survival rates for the entire cohort were 97%, 94%, and 90% and 99%, 98%, and 97%, respectively. Toxicity was scored per event, with 5.4% acute grade 3 genitourinary and 0.2% acute grade 3 gastrointestinal toxicity. Late grade 3 genitourinary and gastrointestinal toxicities were 3.5% and 1.6%, respectively. Two patients developed grade 4 incontinence. No other instance of grade 4 or greater acute or late toxicity was reported. Conclusion: Our results confirm IRT-HDR-BRT is safe and effective as monotherapy for clinically localized prostate cancer.

  15. Analysis of a Statistical Relationship Between Dose and Error Tallies in Semiconductor Digital Integrated Circuits for Application to Radiation Monitoring Over a Wireless Sensor Network

    NASA Astrophysics Data System (ADS)

    Colins, Karen; Li, Liqian; Liu, Yu

    2017-05-01

    Mass production of widely used semiconductor digital integrated circuits (ICs) has lowered unit costs to the level of ordinary daily consumables of a few dollars. It is therefore reasonable to contemplate the idea of an engineered system that consumes unshielded low-cost ICs for the purpose of measuring gamma radiation dose. Underlying the idea is the premise of a measurable correlation between an observable property of ICs and radiation dose. Accumulation of radiation-damage-induced state changes or error events is such a property. If correct, the premise could make possible low-cost wide-area radiation dose measurement systems, instantiated as wireless sensor networks (WSNs) with unshielded consumable ICs as nodes, communicating error events to a remote base station. The premise has been investigated quantitatively for the first time in laboratory experiments and related analyses performed at the Canadian Nuclear Laboratories. State changes or error events were recorded in real time during irradiation of samples of ICs of different types in a 60Co gamma cell. From the error-event sequences, empirical distribution functions of dose were generated. The distribution functions were inverted and probabilities scaled by total error events, to yield plots of the relationship between dose and error tallies. Positive correlation was observed, and discrete functional dependence of dose quantiles on error tallies was measured, demonstrating the correctness of the premise. The idea of an engineered system that consumes unshielded low-cost ICs in a WSN, for the purpose of measuring gamma radiation dose over wide areas, is therefore tenable.

  16. [Study on the safety and efficacy of sitafloxacin at a dose of 100 mg once a day--results of the use-results survey].

    PubMed

    Hori, Seiji; Uchino, Kazuhiro; Matsumoto, Takuyuki; Yamaguchi, Hiroki; Takahashi, Megumi; Hamajima, Satoko; Nukui, Kaori; Eda, Hisano; Shiina, Akiko; Takita, Atsushi; Yamanouchi, Naoki; Mizuno, Masami; Okutani, Yukihiro

    2014-06-01

    Sitafloxacin (STFX, Gracevit 50 mg, fine granules 10%), an oral quinolone antibacterial agent, was approved additionally for administration at a dose of 100 mg once a day in August 2011. A use-results survey on STFX 100 mg/day was performed from December 2011 to May 2013. In total, 1,186 case cards were collected from 226 medical institutions and 1,089 cases were subjected to a safety evaluation and 1,069 were subjected to an efficacy evaluation. The incidence of adverse drug reactions (ADRs) was 2.11% (23/1,089 cases) and no serious ADRs were observed. The major ADR was diarrhea at 1.10% (12/1,089 cases). Of these 12 cases, 10 cases developed symptoms within 4 days of treatment. All of them, except one case that could not be followed up, either recovered or improved. Nonsteroidal anti-inflammatory drugs of the phenyl acetate and propionate types, which require caution when coadministered with STFX, were used concomitantly by 17.6% (192/1,089 cases) of patients but no central nervous system ADRs were observed. The overall efficacy rate was 96.4% (1,030/1,069 cases) and by types of infections, it was 97.0% (387/399 cases) for respiratory tract infections, 96.7% (353/365 cases) for urinary tract infections, 94.7% (36/38 cases) for gynecological infections, 92.3% (132/143 cases) for otorhinolaryngological infections, 98.4% (122/124 cases) for dental and oral surgical infections. The efficacy rate in every category of site of infection exceeded 90%. The overall eradication rate was 94.4% (185/196 strains) including Gram-positive bacteria at 95.4% (62/65 strains), Gram-negative bacteria at 92.2% (94/102 strains), anaerobes at 100.0% (11/11 strains) and atypical bacteria at 100.0% (18/18 strains). In conclusion, this use-results survey confirmed that STFX 100 mg/day is an effective administration with no serious problems in its safety profile and efficacy rate of over 90% in every category of site of infection.

  17. Worker doses and potential health effects resulting from the accident at the Fukushima nuclear power plant in 2011.

    PubMed

    Etherington, George; Zhang, Wei; Harrison, John; Walsh, Linda

    2014-11-01

    The reliability of exposure scenarios used in the World Health Organization's Health Risk Assessment (HRA) for Fukushima workers was examined. HRA risk estimates for cancer incidence in these workers were then reviewed. The HRA constructed four exposure scenarios to estimate worker radiation doses; recent individual dosimetric data were used to assess their reliability. Risks of specified cancer types attributable to radiation exposure were estimated in the HRA by calculating Lifetime Attributable Risks (LAR) for each scenario, and comparisons of LAR are provided. The scenarios were confirmed as reliable for the purposes of the HRA. For the lowest dose scenario (Scenario 1: 69% of the workforce), the HRA found that any elevated cancer risk was insignificant. Significantly elevated cancer risks were, however, found for the three higher dose scenarios. For the highest dose scenario (Scenario 4: 13 workers), LAR values for thyroid cancer up to 3.5% were estimated, but a radiation-related increase in thyroid cancer incidence is unlikely to be observed because of the small number of workers. For the two intermediate dose scenarios, a small number of cancer cases may occur, but these are unlikely to be observed because the variability in baseline rates of cancer incidence is much larger than the predicted radiation-related incidence rates.

  18. Statistical analysis of results from a survey of halon and CFC consumption on US Navy ships. Technical report

    SciTech Connect

    Burns, K.C.; Smitth, D.E.

    1994-08-01

    The Naval Sea Systems Command (NAVSEA) needs to determine the total fleet requirements for ozone-depleting substances until they are phased out. To provide information about the necessary reserves of these substances during the outyears, NAVSEA recently conducted a survey of CFC/Halon usage in the fleet. This document provides a statistical analysis of the data from the survey, which includes reported usage for CFC-ll, CFC-12, CFC-1l4, and Halon 1301. The information in this report can be used to estimate the required CFC/Halon reserves. The average consumption figures can be used as the basis for an expected value approach, while those corresponding to the statistical confidence levels can be used to provide various degrees of guarantee that the estimated reserve will not be depleted prematurely.

  19. Doses measured using AEC on direct digital radiographic (DDR) X-rays systems: updated results with an RP 162 perspective.

    PubMed

    Bowden, L; Faulkner, R; Gallagher, A; O'Connor, U; Walsh, C; Dowling, A; O'Reilly, G

    2013-02-01

    As digital technology in diagnostic radiology systems becomes more prevalent, there is a need to provide comparative dose information for these new systems. This is needed in particular for testing the automatic exposure control (AEC) devices on direct digital radiography (DDR) systems as there is no consensus on the receptor dose level in the current guidelines. The new European Commission RP 162 document sets the suspension level for the 'verification of kerma at receptor entrance in computed radiography and DDR systems under AEC' as ≥10 µGy. This document also notes that alternate methodologies are acceptable, and may require adjustment in the suspension level if used. This study provides a range of typical doses under AEC for DDR systems, for a variety measurement methodologies, including that described in RP 162.

  20. Endometrial effects of lower doses of conjugated equine estrogens and medroxyprogesterone acetate: two-year substudy results.

    PubMed

    Pickar, James H; Yeh, I Tien; Wheeler, James E; Cunnane, Mary F; Speroff, Leon

    2003-11-01

    To determine the endometrial safety of 2 years of treatment with lower doses of continuous combined conjugated equine estrogens (CEE) and medroxyprogesterone acetate (MPA). Randomized, double-blind, placebo-controlled, multicenter metabolic and osteoporosis substudy of the Women's Health, Osteoporosis, Progestin, Estrogen (Women's HOPE) study. Nineteen study centers across the United States. Healthy, postmenopausal women (n = 822) with an intact uterus were recruited. Patients received CEE 0.625, CEE 0.625/MPA 2.5, CEE 0.45, CEE 0.45/MPA 2.5, CEE 0.45/MPA 1.5, CEE 0.3, CEE 0.3/MPA 1.5 (all doses mg/day), or placebo for 2 years. Endometrial biopsies were evaluated at baseline and years 0.5, 1, 1.5, and 2 using a centralized protocol. Efficacy of lower doses of CEE/MPA in reducing the incidence of endometrial hyperplasia rates associated with unopposed estrogen (E). No cases of endometrial hyperplasia were seen in the four CEE/MPA groups. For the CEE-alone groups, a dose-related increase in incidence rates from 3.17% (CEE 0.3 mg) to 27.27% (CEE 0.625 mg) was seen at 2 years. The number of cases increased from year 1 to year 2. For the CEE-alone groups, the incidence rates and types of hyperplasia diagnosed varied among the pathologists. Two years of treatment with lower doses of CEE/MPA provided endometrial protection comparable to that seen with commonly prescribed doses. These regimens should be considered for postmenopausal women who are candidates for hormone therapy.

  1. Nilotinib dose-optimization in newly diagnosed chronic myeloid leukaemia in chronic phase: final results from ENESTxtnd.

    PubMed

    Hughes, Timothy P; Munhoz, Eduardo; Aurelio Salvino, Marco; Ong, Tee Chuan; Elhaddad, Alaa; Shortt, Jake; Quach, Hang; Pavlovsky, Carolina; Louw, Vernon J; Shih, Lee-Yung; Turkina, Anna G; Meillon, Luis; Jin, Yu; Acharya, Sandip; Dalal, Darshan; Lipton, Jeffrey H

    2017-07-12

    The Evaluating Nilotinib Efficacy and Safety in Clinical Trials-Extending Molecular Responses (ENESTxtnd) study was conducted to evaluate the kinetics of molecular response to nilotinib in patients with newly diagnosed chronic myeloid leukaemia in chronic phase and the impact of novel dose-optimization strategies on patient outcomes. The ENESTxtnd protocol allowed nilotinib dose escalation (from 300 to 400 mg twice daily) in the case of suboptimal response or treatment failure as well as dose re-escalation for patients with nilotinib dose reductions due to adverse events. Among 421 patients enrolled in ENESTxtnd, 70·8% (95% confidence interval, 66·2-75·1%) achieved major molecular response (BCR-ABL1 ≤ 0·1% on the International Scale) by 12 months (primary endpoint). By 24 months, 81·0% of patients achieved major molecular response, including 63·6% (56 of 88) of those with dose escalations for lack of efficacy and 74·3% (55 of 74) of those with dose reductions due to adverse events (including 43 of 54 patients with successful re-escalation). The safety profile of nilotinib was consistent with prior studies. The most common non-haematological adverse events were headache, rash, and nausea; cardiovascular events were reported in 4·5% of patients (grade 3/4, 3·1%). The study was registered at clinicaltrials.gov (NCT01254188). © 2017 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.

  2. Confirmation of skin doses resulting from bolus effect of intervening alpha-cradle and carbon fiber couch in radiotherapy.

    PubMed

    Chan, Maria F; Chiu-Tsao, Sou-Tung; Li, Jingdong; Schupak, Karen; Parhar, Preeti; Burman, Chandra

    2012-12-01

    In this study, we verified the treatment planning calculations of skin doses with the incorporation of the bolus effect due to the intervening alpha-cradle (AC) and carbon fiber couch (CFC) using radiochromic EBT2 films. A polystyrene phantom (25 × 25 × 15 cm(3)) with six EBT2 films separated by polystyrene slabs, at depths of 0, 0.1, 0.2, 0.5, 1, 1.4 cm, was positioned above an AC, which was ~1 cm thick. The phantom and AC assembly were CT scanned and the CT-images were transferred to the treatment planning system (TPS) for calculations in three scenarios: (A) ignoring AC and CFC, (B) accounting for AC only, (C) accounting for both AC and CFC. A single posterior 10 × 10 cm(2) field, a pair of posterior-oblique 10 × 10 cm(2) fields, and a posterior IMRT field (6 MV photons from a Varian Trilogy linac) were planned. For each radiation field configuration, the same MU were used in all three scenarios in the TPS. Each plan for scenario C was delivered to expose a stack of EBT2 films in the phantom through AC and CFC. In addition, in vivo EBT2 film measurement on a lung cancer patient immobilized with AC undergoing IMRT was also included in this study. Point doses and planar distributions generated from the TPS for the three scenarios were compared with the data from the EBT2 film measurements. For all the field arrangements, the EBT2 film data including the in vivo measurement agreed with the doses calculated for scenario (C), within the uncertainty of the EBT2 measurements (~4%). For the single posterior field (a pair of posterior-oblique fields), the TPS generated doses were lower than the EBT2 doses by 34%, 33%, 31%, 13% (34%, 31%, 31%, 11%) for scenario A and by 27%, 25%, 22%, 8% (25%, 21%, 21%, 6%) for scenario B at the depths of 0, 0.1, 0.2, 0.5 cm, respectively. For the IMRT field, the 2D dose distributions at each depth calculated in scenario C agree with those measured data. When comparing the central axis doses for the IMRT field, we found the TPS

  3. Generalized results of individualized exposure doses reconstruction for the subjects of Ukrainian State Register of persons, affected due to Chernobyl accident.

    PubMed

    Likhtarov, I A; Kovgan, L M; Masiuk, S V; Ivanova, O M; Chepurny, M I; Boyko, Z N; Gerasymenko, V B; Tereshchenko, S A; Kravchenko, I G; Kortushin, G I; Marcenjyk, O D; Gubina, I G

    2015-12-01

    Since 2007, the department of dosimetry of NRCRM has been working for to supply the Ukrainian State Register (SRU) of persons affected due to Chernobyl accident by exposure doses estimations. As of now, the individualization of doses has been performed for nine raions located in Kyiv, Zhytomyr, Rivne and Chernihiv oblasts. The structure of raion-specific models used for the reconstruction of individualized doses was described in detail in the previous 19-th issue of this journal (2014). The choice conditions for persons from the SRU using which for each raion there was formed a contingent of persons for whom the dose could be reconstructed. During the period of 2007-2015, the individualized dose was reconstructed for 244226 persons in 9 raions, representing ~ 58% of all registered in the SRU inhabitants of the raions. The calculation results were transferred to the SRU in formats adapted to the common database structure of the SRU. For each person who satisfied the conditions of selection there were estimated: (1) possible absorbed internal exposure dose of the thyroid by radioiodine in 1986 (assuming that the person in 1986 lived in the same village and was enlisted in the SRU); (2) annual doses of external, internal and total exposure of the whole body for a period of observation in the SRU; (3) total exposure dose of whole body accumulated during the period of observation in the SRU; (4) the total cumulative dose of feasible exposure during the period since 1986 till the decision to be registered in the SRU. There are presented the generalized results of the SRU subjects distribution for different raions in dependence on intervals of doses accumulated at different periods after the accident. The raion matrix tables show the dynamics of accumulation of doses by the SRU subjects both for their stay on the account and for the period of their possible residence registration in the settlement since 1986. The directions for further research to be implemented for

  4. 42 CFR 82.27 - How can claimants obtain reviews of their NIOSH dose reconstruction results by NIOSH?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES METHODS FOR CONDUCTING DOSE RECONSTRUCTION UNDER THE ENERGY EMPLOYEES OCCUPATIONAL ILLNESS COMPENSATION..., the methods employed in the review, and the review findings to the claimant, DOL, and DOE. ...

  5. Validation of surrogate endpoints in advanced solid tumors: systematic review of statistical methods, results, and implications for policy makers.

    PubMed

    Ciani, Oriana; Davis, Sarah; Tappenden, Paul; Garside, Ruth; Stein, Ken; Cantrell, Anna; Saad, Everardo D; Buyse, Marc; Taylor, Rod S

    2014-07-01

    Licensing of, and coverage decisions on, new therapies should rely on evidence from patient-relevant endpoints such as overall survival (OS). Nevertheless, evidence from surrogate endpoints may also be useful, as it may not only expedite the regulatory approval of new therapies but also inform coverage decisions. It is, therefore, essential that candidate surrogate endpoints be properly validated. However, there is no consensus on statistical methods for such validation and on how the evidence thus derived should be applied by policy makers. We review current statistical approaches to surrogate-endpoint validation based on meta-analysis in various advanced-tumor settings. We assessed the suitability of two surrogates (progression-free survival [PFS] and time-to-progression [TTP]) using three current validation frameworks: Elston and Taylor's framework, the German Institute of Quality and Efficiency in Health Care's (IQWiG) framework and the Biomarker-Surrogacy Evaluation Schema (BSES3). A wide variety of statistical methods have been used to assess surrogacy. The strength of the association between the two surrogates and OS was generally low. The level of evidence (observation-level versus treatment-level) available varied considerably by cancer type, by evaluation tools and was not always consistent even within one specific cancer type. Not in all solid tumors the treatment-level association between PFS or TTP and OS has been investigated. According to IQWiG's framework, only PFS achieved acceptable evidence of surrogacy in metastatic colorectal and ovarian cancer treated with cytotoxic agents. Our study emphasizes the challenges of surrogate-endpoint validation and the importance of building consensus on the development of evaluation frameworks.

  6. [Adherence of type 2 diabetes patients on insulin analogues application: missed dose, time imprecision and dose reduction. The results of GAPP2TM(Global Attitudes of Physicians and Patient) survey in the Czech Republic].

    PubMed

    Prázný, Martin

    2014-11-01

    Irregular insulin dose is one of the main problems associated with insulin therapy in patients with type 2 diabetes; its extent is not known precisely. The aim of survey conducted in the Czech Republic in the international project GAPP2 - Global Attitudes of Patients and Physicians was to determine the incidence and the impact of irregular use of basal insulin analogues in patients with type 2 diabetes, to point out the reasons for these irregularities and to focus on how physicians discuss irregular application of insulin with patients. The project GAPP2 is an international cross-sectional study performed on-line via the Internet using a questionnaire filled by diabetic patients treated with insulin analogues and physicians who treat these patients. The survey was conducted in two steps in 17 countries; the first step included 6 countries and was completed in the beginning of 2012, the second step involved 11 other countries including the Czech Republic with termination in 2014. The survey was designed to obtain the views of patients and physicians on certain aspects of insulin treatment and persistent issues in this field in the real daily practice. Special focus was on the incidence and management of hypoglycaemia as well as on irregularities of insulin application. In the part dedicated to adherence to basal insulin application were observed three types of irregular insulin therapy: missed dose, time imprecision of dose (± 2 hours vs. the prescribed time) and dose reduction in all cases in the past 30 days before completing the questionnaire. In addition, it was investigated the attitude and relation of patients to these issues. The results have shown that irregular insulin dose in the Czech Republic is less frequent than in other countries involved in the GAPP2 research. Nevertheless, approximately one fifth of diabetic patients using insulin analogues in basal-bolus or only basal therapy regimen is related to this problem. The last irregular insulin

  7. Risk of brain tumours in relation to estimated RF dose from mobile phones: results from five Interphone countries

    PubMed Central

    Armstrong, B K; Bowman, J D; Giles, G G; Hours, M; Krewski, D; McBride, M; Parent, M E; Sadetzki, S; Woodward, A; Brown, J; Chetrit, A; Figuerola, J; Hoffmann, C; Jarus-Hakak, A; Montestruq, L; Nadon, L; Richardson, L; Villegas, R; Vrijheid, M

    2011-01-01

    Objectives The objective of this study was to examine the associations of brain tumours with radio frequency (RF) fields from mobile phones. Methods Patients with brain tumour from the Australian, Canadian, French, Israeli and New Zealand components of the Interphone Study, whose tumours were localised by neuroradiologists, were analysed. Controls were matched on age, sex and region and allocated the ‘tumour location’ of their matched case. Analyses included 553 glioma and 676 meningioma cases and 1762 and 1911 controls, respectively. RF dose was estimated as total cumulative specific energy (TCSE; J/kg) absorbed at the tumour's estimated centre taking into account multiple RF exposure determinants. Results ORs with ever having been a regular mobile phone user were 0.93 (95% CI 0.73 to 1.18) for glioma and 0.80 (95% CI 0.66 to 0.96) for meningioma. ORs for glioma were below 1 in the first four quintiles of TCSE but above 1 in the highest quintile, 1.35 (95% CI 0.96 to 1.90). The OR increased with increasing TCSE 7+ years before diagnosis (p-trend 0.01; OR 1.91, 95% CI 1.05 to 3.47 in the highest quintile). A complementary analysis in which 44 glioma and 135 meningioma cases in the most exposed area of the brain were compared with gliomas and meningiomas located elsewhere in the brain showed increased ORs for tumours in the most exposed part of the brain in those with 10+ years of mobile phone use (OR 2.80, 95% CI 1.13 to 6.94 for glioma). Patterns for meningioma were similar, but ORs were lower, many below 1.0. Conclusions There were suggestions of an increased risk of glioma in long-term mobile phone users with high RF exposure and of similar, but apparently much smaller, increases in meningioma risk. The uncertainty of these results requires that they be replicated before a causal interpretation can be made. PMID:21659469

  8. Long-term results of a pilot study of low dose cranial-spinal irradiation for cerebellar medulloblastoma

    SciTech Connect

    Brand, W.N.; Schneider, P.A.; Tokars, R.P.

    1987-11-01

    Between May 1974 and March 1983, 44 children with histologically verified cerebellar medulloblastoma were seen for post-operative cranial-spinal irradiation following attempted total tumor removal. Six patients were excluded from review because they received all or part of their treatment at another institution (3 patients) or did not complete the planned course of irradiation (3 patients). All of the 38 remaining patients were treated by a previously described technique on a 4 MeV Linear Accelerator with 55 Gy delivered to the primary tumor site. Prior to December 1978, 19 consecutive children (Group A) had spinal prophylactic doses of 30-40 Gy and brain prophylactic doses of 40-50 Gy. After the date, 25 Gy was given to the cranial-spinal axis of 19 consecutive children (Group B). This lower dose was arbitrarily selected with the hope of reducing morbidity in treated survivors and achieving the same tumor control. Risk factors that define good and poor prognosis were evaluated for each group, and there were no differences noted. Myelography and CSF cytology were not routinely performed. Follow-up for the 38 patients ranges from 20 months to 124 months. For the low risk patients, survival (12/15 or 80%) was independent of cranial-spinal radiation dose (Group A 6/8, Group B 6/7). For the high risk patients survival was poor (9/23 or 39%), not dependent on cranial-spinal radiation dose (Group A 5/11, Group B 4/12), and associated with failure at the primary site (10/14), often with CSF seeding (8/10). The other 4 failures include 2 who had moved outside the United States (details of failure are unknown), 1 with supratentorial, CSF seeding and distant metastases, and 1 with distant metastasis only.

  9. Pharmacokinetics of fixed-dose combination of tenofovir disoproxil fumarate, lamivudine, and efavirenz: results of a randomized, crossover, bioequivalence study.

    PubMed

    Abhyankar, Dhiraj; Shedage, Ashish; Gole, Milind; Raut, Preeti

    2016-06-17

    The objective of this study was to assess the bioequivalence between a fixed-dose combination of tenofovir disoproxil fumarate/lamivudine/efavirenz 300/300/600 mg and the individual innovator products. A randomized, balanced, open-label, two-sequence, two-treatment, two-period, single dose, crossover study in 48 healthy adults was conducted. Dosing was separated by a washout period of 32 days. Twenty-seven blood samples were collected in each period from pre-dose to 72 h post-dose. The data of 45 subjects were analyzed for pharmacokinetics and safety. Ninety percent CIs of geometric mean ratio on Cmax, AUC0-t, and AUC0-inf for tenofovir and lamivudine and on Cmax and AUC0-72 for efavirenz were within the acceptance criteria (80-125%). For tenofovir disoproxil fumarate, the Tmax, Kel, and t1/2 values for the test and reference products were 1.02 versus 0.91 h, 0.04 versus 0.04/h, 18.67 versus 18.46 h, respectively. For lamivudine, the Tmax, Kel, and t1/2 values were: 1.38 versus 1.30 h, 0.21 versus 0.19/h, 3.44 versus 3.91 h, respectively. For efavirenz, the Tmax values for the test and reference products were 3.71 and 3.65 h, respectively. Both the treatments were well tolerated. Our findings suggest that the tested formulation is bioequivalent to the innovators' formulations, and both treatments were well tolerated.

  10. Low-dose irradiation prior to bone marrow transplantation results in ATM activation and increased lethality in Atm-deficient mice.

    PubMed

    Pietzner, J; Merscher, B M; Baer, P C; Duecker, R P; Eickmeier, O; Fußbroich, D; Bader, P; Del Turco, D; Henschler, R; Zielen, S; Schubert, R

    2016-04-01

    Ataxia telangiectasia is a genetic instability syndrome characterized by neurodegeneration, immunodeficiency, severe bronchial complications, hypersensitivity to radiotherapy and an elevated risk of malignancies. Repopulation with ATM-competent bone marrow-derived cells (BMDCs) significantly prolonged the lifespan and improved the phenotype of Atm-deficient mice. The aim of the present study was to promote BMDC engraftment after bone marrow transplantation using low-dose irradiation (IR) as a co-conditioning strategy. Atm-deficient mice were transplanted with green fluorescent protein-expressing, ATM-positive BMDCs using a clinically relevant non-myeloablative host-conditioning regimen together with TBI (0.2-2.0 Gy). IR significantly improved the engraftment of BMDCs into the bone marrow, blood, spleen and lung in a dose-dependent manner, but not into the cerebellum. However, with increasing doses, IR lethality increased even after low-dose IR. Analysis of the bronchoalveolar lavage fluid and lung histochemistry revealed a significant enhancement in the number of inflammatory cells and oxidative damage. A delay in the resolution of γ-H2AX-expression points to an insufficient double-strand break repair capacity following IR with 0.5 Gy in Atm-deficient splenocytes. Our results demonstrate that even low-dose IR results in ATM activation. In the absence of ATM, low-dose IR leads to increased inflammation, oxidative stress and lethality in the Atm-deficient mouse model.

  11. Literature review of some selected types of results and statistical analyses of total-ozone data. [for the ozonosphere

    NASA Technical Reports Server (NTRS)

    Myers, R. H.

    1976-01-01

    The depletion of ozone in the stratosphere is examined, and causes for the depletion are cited. Ground station and satellite measurements of ozone, which are taken on a worldwide basis, are discussed. Instruments used in ozone measurement are discussed, such as the Dobson spectrophotometer, which is credited with providing the longest and most extensive series of observations for ground based observation of stratospheric ozone. Other ground based instruments used to measure ozone are also discussed. The statistical differences of ground based measurements of ozone from these different instruments are compared to each other, and to satellite measurements. Mathematical methods (i.e., trend analysis or linear regression analysis) of analyzing the variability of ozone concentration with respect to time and lattitude are described. Various time series models which can be employed in accounting for ozone concentration variability are examined.

  12. Efficacy of fixed-dosing aflibercept for treating polypoidal choroidal vasculopathy: 1-year results of the VAULT study.

    PubMed

    Lee, Joo Eun; Shin, Jae Pil; Kim, Hyun Woong; Chang, Woohyok; Kim, Yu Cheol; Lee, Sang Joon; Chung, In Young; Lee, Ji Eun

    2017-03-01

    To investigate fixed-dosing aflibercept for treating polypoidal choroidal vasculopathy (PCV). This phase IV, prospective, single-arm, interventional case series was conducted in eight centers. Forty treatment-naïve PCV patients were administered three monthly doses of intravitreal aflibercept (2.0 mg) and an injection every 2 months thereafter. Best-corrected visual acuity (BCVA) and central subfield macular thickness (CSMT) were measured at each visit. Fluorescein and indocyanine green angiography (ICGA) were performed at baseline, 3 and 12 months. The primary outcome measure was the proportion of patients who maintained BCVA (<15 letters loss) at 12 months. Changes in BCVA, macular appearance, and polypoidal lesion appearance were also examined. Thirty-five eyes (87.5 %) had maintained BCVA at 12 months. Average BCVA was significantly higher at 12 months (20/53, 64.2 letters) than at baseline (20/80, 55.1 letters, 9-letter gain; P < .001). Mean CSMT was significantly lower at 12 months (253.6 μm) than at baseline (365.2 μm, P < .001). The macula was dry in 32 (76.2 %), 27 (64.3 %), and 24 eyes (60.0 %) at 3, 6, and 12 months respectively. Fourteen eyes (33.3 %) had a fluid recurrence or increase at 6 months, and they had a significantly lower vision gain (P = .005) than other patients at 12 months. Complete polyp regression occurred in 26 eyes (66.7 %) at 12 months. Fixed-dosing aflibercept showed favorable outcomes in PCV patients at 12 months. However, some patients had worse outcomes because of fluid recurrence during maintenance dosing, and these patients would require additional treatments.

  13. Bosutinib plus capecitabine for selected advanced solid tumours: results of a phase 1 dose-escalation study.

    PubMed

    Isakoff, S J; Wang, D; Campone, M; Calles, A; Leip, E; Turnbull, K; Bardy-Bouxin, N; Duvillié, L; Calvo, E

    2014-11-25

    This phase 1 study evaluated the maximum tolerated dose (MTD), safety, and efficacy of bosutinib (competitive Src/Abl tyrosine kinase inhibitor) plus capecitabine. Patients with locally advanced/metastatic breast, pancreatic, or colorectal cancers; cholangiocarcinoma; or glioblastoma received bosutinib plus capecitabine at eight of nine possible dose combinations using an 'up-down' design to determine the toxicity contour of the combination. Among 32 enrolled patients, none of the 9 patients receiving MTD (bosutinib 300 mg once daily plus capecitabine 1000 mg m(-2) twice daily) experienced dose-limiting toxicities (DLTs). Overall, 2 out of 31 (6%) evaluable patients experienced DLTs (grade 3 neurologic pain (n=1); grade 3 pruritus/rash and increased alanine aminotransferase (n=1)). Most common treatment-related adverse events (AEs) were diarrhoea, nausea, vomiting, palmar-plantar erythrodysesthesia (PPE), fatigue; most frequent grade 3/4 AEs: PPE, fatigue, and increased alanine/aspartate aminotransferase. Although diarrhoea was common, 91% of affected patients experienced maximum grade 1/2 events that resolved. Best overall confirmed partial response or stable disease >24 weeks (all tumour types) was observed in 6 and 13% of patients. In this population of patients with advanced solid tumours, bosutinib plus capecitabine demonstrated a safety profile similar to that previously reported for bosutinib or capecitabine monotherapy; limited efficacy was observed.

  14. Higher rate of microscopic hematuria in elderly patients who take regular doses of aspirin: Result from AHAP Study.

    PubMed

    Moudi, Emadouddin; Hosseini, Seyed-Reza; Bijani, Ali

    2016-01-01

    Aspirin is the most widely used drug in medicine for cardiovascular and as recently for its role in cancer prevention. Although the risk of bleeding events increased following regular use of aspirin, little is known about the association of aspirin and hematuria. The present study aimed to evaluate the association of regular aspirin use and microscopic hematuria in elderly. In this study, we have extracted the data of elderly people who participated in Amirkola Health and Aging Project (AHAP) and taking regular doses of aspirin. The prevalence of microscopic hematuria was compared between the elderly who took aspirin regularly and those who did not take it. A total of 1243 individuals (54.22% males, 45.78% females) were entered in to the study. Two hundred and eighty-four (23%) elderly took regular doses of aspirin. Microscopic hematuria was seen in 305 (24.54%) elderly. The prevalence of microscopic hematuria was 27.27% in regular users of aspirin and 23.72% in non-users of aspirin (P=0.126). The prevalence of microscopic hematuria was significantly higher among the regular users of aspirin compared to non-users in multiple logistic regression analysis (P=0.035, OR=1.40, 95%CI: 1.02-1.92). Taking regular doses of aspirin was accompanied with higher rate of microscopic hematuria in the elderly.

  15. Bendamustine, thalidomide and dexamethasone combination therapy for relapsed/refractory myeloma patients: results of the MUKone randomized dose selection trial.

    PubMed

    Schey, Steve; Brown, Sarah R; Tillotson, Avie-Lee; Yong, Kwee; Williams, Cathy; Davies, Faith; Morgan, Gareth; Cavenagh, Jamie; Cook, Gordon; Cook, Mark; Orti, Guillermo; Morris, Curly; Sherratt, Debbie; Flanagan, Louise; Gregory, Walter; Cavet, James

    2015-08-01

    There is a significant unmet need in effective therapy for relapsed myeloma patients once they become refractory to bortezomib and lenalidomide. While data from the front line setting suggest bendamustine is superior to melphalan, there is no information defining optimal bendamustine dose in multiply-treated patients. We report a multi-centre randomized two-stage phase 2 trial simultaneously assessing deliverability and activity of two doses of bendamustine (60 mg/m2 vs. 100 mg/m2) days 1 and 8, thalidomide (100 mg) days 1-21 and low dose dexamethasone (20 mg) days 1, 8, 15 and 22 of a 28-d cycle. Ninety-four relapsing patients were treated on trial, with a median three prior treatment lines. A pre-planned interim deliverability and activity assessment led to closure of the 100 mg/m2 arm due to excess cytopenias, and led to amendment of entry criteria for cytopenias. Non-haematological toxicities including thromboembolism and neurotoxicity were infrequent. In the 60 mg/m2 arm, treatment was deliverable in 61.1% subjects and the partial response rate was 46.3% in the study eligible population, with 7.5 months progression-free survival. This study demonstrates bendamustine at 60 mg/m2 twice per month with thalidomide and dexamethasone is deliverable for repeated cycles in heavily pre-treated myeloma patients and has substantial clinical activity.

  16. Outcomes in patients with chronic kidney disease not on dialysis receiving extended dosing regimens of darbepoetin alfa: long-term results of the EXTEND observational cohort study

    PubMed Central

    Galle, Jan-Christoph; Addison, Janet; Suranyi, Michael G.; Claes, Kathleen; Di Giulio, Salvatore; Guerin, Alain; Herlitz, Hans; Kiss, István; Farouk, Mourad; Manamley, Nick; Wirnsberger, Gerhard; Winearls, Christopher

    2016-01-01

    Background Extended dosing of the erythropoiesis-stimulating agent (ESA) darbepoetin alfa (DA) once biweekly or monthly reduces anaemia treatment burden. This observational study assessed outcomes and dosing patterns in patients with chronic kidney disease not on dialysis (CKD-NoD) commencing extended dosing of DA. Methods Adult CKD-NoD patients starting extended dosing of DA in Europe or Australia in June 2006 or later were followed up until December 2012. Outcomes included haemoglobin (Hb) concentration, ESA dosing, mortality rates and receipt of dialysis and renal transplantation. Subgroup analyses were conducted for selected outcomes. Results Of 6035 enrolled subjects, 5723 (94.8%) met analysis criteria; 1795 (29.7%) received dialysis and 238 (3.9%) underwent renal transplantation. Mean (standard deviation) Hb concentration at commencement of extended dosing was 11.0 (1.5) g/dL. Mean [95% confidence interval (CI)] Hb 12 months after commencement of extended dosing (primary outcome) was 11.6 g/dL (11.5, 11.6) overall and was similar across countries, with no differences between subjects previously treated with an ESA versus ESA-naïve subjects, subjects with versus without prior renal transplant or diabetics versus non-diabetics. Weekly ESA dose gradually decreased following commencement of extended DA dosing and was similar across subgroups. The decrease in weekly DA dose was accompanied by an increase in the proportion of patients receiving iron therapy. Hb concentrations declined following changes in ESA labels and treatment guidelines. The mortality rate (95% CI) was 7.06 (6.68, 7.46) deaths per 100 years of follow-up. Subjects alive at study end had stable Hb concentrations in the preceding year, while those who died had lower and declining Hb concentrations in their last year. Conclusions Long-term, extended dosing of DA maintained Hb concentrations in patients already treated with an ESA and corrected and maintained Hb in ESA-naïve patients. PMID

  17. Statistics Clinic

    NASA Technical Reports Server (NTRS)

    Feiveson, Alan H.; Foy, Millennia; Ploutz-Snyder, Robert; Fiedler, James

    2014-01-01

    Do you have elevated p-values? Is the data analysis process getting you down? Do you experience anxiety when you need to respond to criticism of statistical methods in your manuscript? You may be suffering from Insufficient Statistical Support Syndrome (ISSS). For symptomatic relief of ISSS, come for a free consultation with JSC biostatisticians at our help desk during the poster sessions at the HRP Investigators Workshop. Get answers to common questions about sample size, missing data, multiple testing, when to trust the results of your analyses and more. Side effects may include sudden loss of statistics anxiety, improved interpretation of your data, and increased confidence in your results.

  18. Results of Hematopoietic Stem Cell Transplantation After Treatment With Different High-Dose Total-Body Irradiation Regimens in Five Dutch Centers

    SciTech Connect

    Loes van Kempen-Harteveld, M. Brand, Ronald; Kal, Henk B.; Verdonck, Leo F.; Hofman, Pieter; Schattenberg, Anton V.; Maazen, Richard W. van der; Cornelissen, Jan J.; Eijkenboom, Wil M.H.; Lelie, Johannes P. van der; Oldenburger, Foppe; Barge, Renee M.; Biezen, Anja van; Vossen, Jaak M.J.J.; Noordijk, Evert M.; Struikmans, Henk

    2008-08-01

    Purpose: To evaluate results of high-dose total-body irradiation (TBI) regimens for hematopoietic stem cell transplantation. Methods and Materials: A total of 1,032 patients underwent TBI in one or two fractions before autologous or allogeneic hematologic stem cell transplantation for acute leukemia and non-Hodgkin's lymphoma. The TBI regimens were normalized by using the biological effective dose (BED) concept. The BED values were divided into three dose groups. Study end points were relapse incidence (RI), non-relapse mortality (NRM), relapse-free survival (RFS), and overall survival (OS). Multivariate analysis was performed, stratified by disease. Results: In the highest TBI dose group, RI was significantly lower and NRM was higher vs. the lower dose groups. However, a significant influence on RFS and OS was not found. Relapses in the eye region were found only after shielding to very low doses. Age was of significant influence on OS, RFS, and NRM in favor of younger patients. The NRM of patients older than 40 years significantly increased, and OS decreased. There was no influence of age on RI. Men had better OS and RFS and lower NRM. Type of transplantation significantly influenced RI and NRM for patients with acute leukemia and non-Hodgkin's lymphoma. There was no influence on RFS and OS. Conclusions: Both RI and NRM were significantly influenced by the size of the BED of single-dose or two-fraction TBI regimens; OS and RFS were not. Age was of highly significant influence on NRM, but there was no influence of age on RI. Hyperfractionated TBI with a high BED might be useful, assuming NRM can be reduced.

  19. A statistical approach for site error correction in lightning location networks with DF/TOA technique and its application results

    NASA Astrophysics Data System (ADS)

    Lu, Tao; Chen, Mingli; Du, Yaping; Qiu, Zongxu

    2017-02-01

    Lightning location network (LLN) with DF/TOA (direction-finder/time-of-arrival) combined technique has been widely used in the world. However, the accuracy of the lightning data from such LLNs has still been restricted by "site error", especially for those detected only by two DF/TOA sensors. In this paper we practice a statistical approach for evaluation and correction of "site error" for DF/TOA type LLN based on its lightning data. By comparing lightning locations recorded by at least 4 sensors between DF and TOA techniques, the spatial characteristics of "site error" for each sensor in the network can be obtained. The obtained "site error" then can be used to improve the accuracy of lightning locations especially those recorded by only 2 sensors. With this approach, the "site error" patterns for 23 sensors in Yunnan LLN are obtained. The features of these site error patterns are in good consistency with those in literature. Significant differences in lightning locations before and after "site error" corrections indicate that the proposed approach works effectively.

  20. Rates of false flagging due to statistical artifact in CMS evaluations of transplant programs: results of a stochastic simulation.

    PubMed

    Massie, A B; Segev, D L

    2013-08-01

    The recent CMS conditions of participation are based on risk-adjusted models produced by the Scientific Registry for Transplant Recipients (SRTR). The accuracy of these models in identifying poor-performing centers is unknown. In this stochastic simulation study, 1-year mortality outcomes were simulated in virtual transplant centers, and used to flag centers according to the methods used by CMS, evaluating nine overlapping 2.5-year periods of simulated data. In a simulation where all centers had the same underlying risk, 10.2% were falsely flagged at least once during the 4.5 years of simulated evaluations. The probability of false-positive flagging was lowest in low-volume centers (2.5%) and highest in high-volume centers (16.2%). In another simulation where 5% of centers were assigned twofold risk ("poor-performing centers"), only 32% of poor-performing centers were correctly flagged. In a final simulation where each center was assigned a unique mortality risk, 94% of flagged centers had greater-than-median risk, but only 32% of flagged centers were among the 5% with highest risk. Even after disregarding known covariate limitations to the risk adjustment models, statistical noise alone leads to spurious flagging of many adequately-performing transplant centers, yet the methods used by CMS fail to flag most centers with true elevated risk. © Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons.

  1. Neutrophil volume, conductivity and scatter parameters with effective modeling of molecular activity statistical program gives better results in neonatal sepsis.

    PubMed

    Celik, I H; Demirel, G; Sukhachev, D; Erdeve, O; Dilmen, U

    2013-02-01

    Neonatal sepsis remains an important clinical syndrome despite advances in neonatology. Current hematology analyzers can determine cell volume (V), conductivity for internal composition of cell (C) and light scatter for cytoplasmic granularity and nuclear structure (S), and standard deviations which are effective in the diagnosis of sepsis. Statistical models can be used to strengthen the diagnosis. Effective modeling of molecular activity (EMMA) uses combinatorial algorithm of the selection parameters for regression equation based on modified stepwise procedure. It allows obtaining different regression models with different combinations of parameters. We investigated these parameters in screening of neonatal sepsis. We used LH780 hematological analyzer (Beckman Coulter, Fullerton, CA, USA). We combined these parameters with interleukin-6 (IL-6) and C-reactive protein (CRP) and developed models by EMMA. A total of 304 newborns, 76 proven sepsis, 130 clinical sepsis and 98 controls, were enrolled in the study. Mean neutrophil volume (MNV) and volume distribution width (VDW) were higher in both proven and clinical sepsis groups. We developed three models using MNV, VDW, IL-6, and CRP. These models gave more sensitivity and specificity than the usage of each marker alone. We suggest to use the combination of MNV and VDW with markers such as CRP and IL-6, and use diagnostic models created by EMMA. © 2012 Blackwell Publishing Ltd.

  2. An evaluation of the quality of statistical design and analysis of published medical research: results from a systematic survey of general orthopaedic journals.

    PubMed

    Parsons, Nick R; Price, Charlotte L; Hiskens, Richard; Achten, Juul; Costa, Matthew L

    2012-04-25

    The application of statistics in reported research in trauma and orthopaedic surgery has become ever more important and complex. Despite the extensive use of statistical analysis, it is still a subject which is often not conceptually well understood, resulting in clear methodological flaws and inadequate reporting in many papers. A detailed statistical survey sampled 100 representative orthopaedic papers using a validated questionnaire that assessed the quality of the trial design and statistical analysis methods. The survey found evidence of failings in study design, statistical methodology and presentation of the results. Overall, in 17% (95% confidence interval; 10-26%) of the studies investigated the conclusions were not clearly justified by the results, in 39% (30-49%) of studies a different analysis should have been undertaken and in 17% (10-26%) a different analysis could have made a difference to the overall conclusions. It is only by an improved dialogue between statistician, clinician, reviewer and journal editor that the failings in design methodology and analysis highlighted by this survey can be addressed.

  3. Ibandronate dose response is associated with increases in bone mineral density and reductions in clinical fractures: results of a meta-analysis.

    PubMed

    Sebba, Anthony I; Emkey, Ronald D; Kohles, Joseph D; Sambrook, Philip N

    2009-03-01

    This meta-analysis pooled data from the four phase III clinical trials of ibandronate to assess the relationship between ibandronate dose, changes in bone mineral density, and rates of both clinical and non-vertebral fractures. Individual patient data from the intent-to-treat population of the BONE, IV fracture prevention, MOBILE, and DIVA studies were included for analysis. The relationship between ibandronate dose and bone mineral density at both the lumbar spine and at the total hip was assessed qualitatively. The relationship between lumbar spine bone mineral density and clinical fracture rate, and the relationship between total hip bone mineral density and non-vertebral fracture rate, were assessed both qualitatively and using mathematical models. A total of 8710 patients were included in this analysis. Both lumbar spine and total hip bone mineral density were observed to increase with increasing ibandronate dose. The incidence of all clinical fractures was observed to decrease as lumbar spine bone mineral density increased. A statistically significant inverse linear relationship was observed between percent change in lumbar spine bone mineral density and the rate of clinical fractures (P=0.005). A non-significant curvilinear relationship was observed between percent change in total hip bone mineral density and non-vertebral fracture rate. Increased ibandronate exposure is associated with increasing gains in the lumbar spine bone mineral density and decreasing clinical fracture rates. A non-linear relationship may exist between increases in the total hip bone mineral density and non-vertebral fracture rate.

  4. Preliminary Results of a Phase 1 Dose-Escalation Trial for Early-Stage Breast Cancer Using 5-Fraction Stereotactic Body Radiation Therapy for Partial-Breast Irradiation.

    PubMed

    Rahimi, Asal; Thomas, Kimberly; Spangler, Ann; Rao, Roshni; Leitch, Marilyn; Wooldridge, Rachel; Rivers, Aeisha; Seiler, Stephen; Albuquerque, Kevin; Stevenson, Stella; Goudreau, Sally; Garwood, Dan; Haley, Barbara; Euhus, David; Heinzerling, John; Ding, Chuxiong; Gao, Ang; Ahn, Chul; Timmerman, Robert

    2017-05-01

    To evaluate the tolerability of a dose-escalated 5-fraction stereotactic body radiation therapy for partial-breast irradiation (S-PBI) in treating early-stage breast cancer after partial mastectomy; the primary objective was to escalate dose utilizing a robotic stereotactic radiation system treating the lumpectomy cavity without exceeding the maximum tolerated dose. Eligible patients included those with ductal carcinoma in situ or invasive nonlobular epithelial histologies and stage 0, I, or II, with tumor size <3 cm. Patients and physicians completed baseline and subsequent cosmesis outcome questionnaires. Starting dose was 30 Gy in 5 fractions and was escalated by 2.5 Gy total for each cohort to 40 Gy. In all, 75 patients were enrolled, with a median age of 62 years. Median follow-up for 5 cohorts was 49.9, 42.5, 25.7, 20.3, and 13.5 months, respectively. Only 3 grade 3 toxicities were experienced. There was 1 dose-limiting toxicity in the overall cohort. Ten patients experienced palpable fat necrosis (4 of which were symptomatic). Physicians scored cosmesis as excellent or good in 95.9%, 100%, 96.7%, and 100% at baseline and 6, 12, and 24 months after S-PBI, whereas patients scored the same periods as 86.5%, 97.1%, 95.1%, and 95.3%, respectively. The disagreement rates between MDs and patients during those periods were 9.4%, 2.9%, 1.6%, and 4.7%, respectively. There have been no recurrences or distant metastases. Dose was escalated to the target dose of 40 Gy in 5 fractions, with the occurrence of only 1 dose-limiting toxicity. Patients felt cosmetic results improved within the first year after surgery and stereotactic body radiation therapy. Our results show minimal toxicity with excellent cosmesis; however, further follow-up is warranted in future studies. This study is the first to show the safety, tolerability, feasibility, and cosmesis results of a 5-fraction dose-escalated S-PBI treatment for early-stage breast cancer in the adjuvant setting

  5. Encephalopathy is the dose-limiting toxicity of intravenous hepsulfam: results of a phase I trial in patients with advanced hematological malignancies.

    PubMed

    Larson, R A; Geller, R B; Janisch, L; Milton, J; Grochow, L B; Ratain, M J

    1995-01-01

    Hepsulfam is a bisulfamic ester which is similar in structure to busulfan and is believed to act as a bifunctional alkylator inducing both DNA-DNA and DNA-protein crosslinks. Prior studies in patients with refractory solid tumors have identified the dose-limiting toxicity of hepsulfam to be cumulative myelosuppression resulting in prolonged leukopenia and thrombocytopenia. This phase I trial was designed to determine the maximally tolerated dose of hepsulfam administered intravenously in patients with refractory leukemias and other advanced hematologic malignancies. Hepsulfam was administered as a 30-min or 2-h intravenous infusion to 21 patients with advanced leukemia or multiple myeloma. All patients had been extensively treated and had progressive disease. Cycles were repeated every 5 weeks. Cohorts of patients were treated at 360, 480, 640, and 800 mg/m2. The dose-limiting toxicity of intravenous hepsulfam was severe encephalopathy. The single patient treated at 800 mg/m2 became comatose within 48 h and required 3 weeks for his mental status to return to baseline. There were, however, no irreversible neurological sequelae. Several patients treated at 640 mg/m2 had clinical evidence of toxic deliriums and slowing of alpha rhythm waves on electroencephalograms indicative of a gray-matter encephalopathy. When hepsulfam was infused over 30 min, patients complained of uncomfortable parasthesias, but when the drug was administered over 2 h, these acute symptoms were less common. Myelosuppression was observed in most patients. Among those patients who had some suppression of their leukemia, peripheral blood counts recovered to pretreatment levels after 3-5 weeks. Apart from CNS toxicity, non-hematologic toxicity was minimal. Pharmacokinetic studies demonstrated rapid clearance of hepsulfam so that the drug was not reliably detected in the plasma after 24 h. The recommended phase II dose of hepsulfam as a single 2-h intravenous infusion is 480 mg/m2, but this dose

  6. TOWARD COMPLETE STATISTICS OF MASSIVE BINARY STARS: PENULTIMATE RESULTS FROM THE CYGNUS OB2 RADIAL VELOCITY SURVEY