WorldWideScience

Sample records for dose ratio produced

  1. Evaluation of the dose uniformity for double-plane high dose rate interstitial breast implants with the use of dose reference points and dose non-uniformity ratio

    International Nuclear Information System (INIS)

    MAjor, T.; Polgar, C.; Somogyi, A.; Nemeth, G.

    2000-01-01

    This study investigated the influence of dwell time optimizations on dose uniformity characterized by dose values in dose points and dose non-uniformity ratio (DNR) and analyzed which implant parameters have influence on the DNR. Double-plane breast implants with catheters arranged in triangular pattern were used for the calculations. At a typical breast implant, dose values in dose reference points inside the target volume and volumes enclosed by given isodose surfaces were calculated and compared for non-optimized and optimized implants. The same 6-cm treatment length was used for the comparisons. Using different optimizations plots of dose non-uniformity ratio as a function of catheter separation, source step size, number of catheters, length of active sections were drawn and the minimum DNR values were determined. Optimization resulted in less variation in dose values over dose points through the whole volume and in the central plane only compared to the non-optimized case. At implant configurations consisting of seven catheters with 15-mm separation, 5-mm source step size and various active lengths adapted according to the type of optimization, the no optimization, geometrical (volume mode) and dose point (on dose points and geometry) optimization resulted in similar treatment volumes, but an increased high dose volume was observed due to the optimization. The dose non-uniformity ratio always had the minimum at average dose over dose normalization points, defined in the midpoints between the catheters through the implant volume. The minimum value of DNR depended on catheter separation, source step size, active length and number of catheters. The optimization had only a small influence on DNR. In addition to the reference points in the central plane only, dose points positioned in the whole implant volume can be used for evaluating the dose uniformity of interstitial implants. The dose optimization increases not only the dose uniformity within the implant but

  2. Influence of Genotype on Warfarin Maintenance Dose Predictions Produced Using a Bayesian Dose Individualization Tool.

    Science.gov (United States)

    Saffian, Shamin M; Duffull, Stephen B; Roberts, Rebecca L; Tait, Robert C; Black, Leanne; Lund, Kirstin A; Thomson, Alison H; Wright, Daniel F B

    2016-12-01

    A previously established Bayesian dosing tool for warfarin was found to produce biased maintenance dose predictions. In this study, we aimed (1) to determine whether the biased warfarin dose predictions previously observed could be replicated in a new cohort of patients from 2 different clinical settings, (2) to explore the influence of CYP2C9 and VKORC1 genotype on predictive performance of the Bayesian dosing tool, and (3) to determine whether the previous population used to develop the kinetic-pharmacodynamic model underpinning the Bayesian dosing tool was sufficiently different from the test (posterior) population to account for the biased dose predictions. The warfarin maintenance doses for 140 patients were predicted using the dosing tool and compared with the observed maintenance dose. The impact of genotype was assessed by predicting maintenance doses with prior parameter values known to be altered by genetic variability (eg, EC50 for VKORC1 genotype). The prior population was evaluated by fitting the published kinetic-pharmacodynamic model, which underpins the Bayesian tool, to the observed data using NONMEM and comparing the model parameter estimates with published values. The Bayesian tool produced positively biased dose predictions in the new cohort of patients (mean prediction error [95% confidence interval]; 0.32 mg/d [0.14-0.5]). The bias was only observed in patients requiring ≥7 mg/d. The direction and magnitude of the observed bias was not influenced by genotype. The prior model provided a good fit to our data, which suggests that the bias was not caused by different prior and posterior populations. Maintenance doses for patients requiring ≥7 mg/d were overpredicted. The bias was not due to the influence of genotype nor was it related to differences between the prior and posterior populations. There is a need for a more mechanistic model that captures warfarin dose-response relationship at higher warfarin doses.

  3. Absorbed dose rate produced by patients with I-131

    International Nuclear Information System (INIS)

    Gonzalez-Vila, V.; Luis-Simon, J.; Gomez-Puerto, A.; Rodriguez, J.R.

    1992-01-01

    This paper shows the values of absorbed dose rates per unit of activity produced by patients treated with Iodine 131 due to Thyroid cancer. Average values related to disease extension, age and sex are established according to out current schedule of Radiological Protection Measures. From this data we have obtained a more accurate calculation for the value used in clinical emergency : 1471 nGy/>MBq over the relevant tissue. 40 treatment performed during 14 months are studied and comments are made on the Iodine retention by thyroideal tissue related to patient's clinical conditions as well size and site of thyroideal tissue and/or TSH simulation. (author)

  4. The ratios of effective dose to entrance skin dose to the air kerma for some medical sources

    Energy Technology Data Exchange (ETDEWEB)

    Wise, K.N. [Australian Radiation Laboratory, Yallambie, VIC (Australia)

    1998-03-01

    Results are presented for the ratios of the effective dose to skin entrance dose and to air kerma for broad beams of radiation expected to be encountered by medical workers. These workers are monitored by the Personal Radiation Monitoring Service (PRMS) using thermoluminescent dosimeters worn at the front of the body to provide estimates of the entrance skin dose. Factors are given for converting estimates of entrance skin dose to effective dose as defined by the International Commission on Radiological Protection (ICRP 1991) for beams incident on the body by one of three modes-from the front of the subject, from the back of the subject or by rotation around the subject. Additional tables are also given to calculate effective dose for these beams from a measurement of air kerma free-in-air 4 figs., 9 tabs.

  5. Effective dose to immuno-PET patients due to metastable impurities in cyclotron produced zirconium-89

    Science.gov (United States)

    Alfuraih, Abdulrahman; Alzimami, Khalid; Ma, Andy K.; Alghamdi, Ali; Al Jammaz, Ibrahim

    2014-11-01

    Immuno-PET is a nuclear medicine technique that combines positron emission tommography (PET) with radio-labeled monoclonal antibodies (mAbs) for tumor characterization and therapy. Zirconium-89 (89Zr) is an emerging radionuclide for immuno-PET imaging. Its long half-life (78.4 h) gives ample time for the production, the administering and the patient uptake of the tagged radiopharmaceutical. Furthermore, the nuclides will remain in the tumor cells after the mAbs are catabolized so that time series studies are possible without incurring further administration of radiopharmarceuticals. 89Zr can be produced in medical cyclotrons by bombarding an yttrium-89 (89Y) target with a proton beam through the 89Y(p,n)89Zr reaction. In this study, we estimated the effective dose to the head and neck cancer patients undergoing 89Zr-based immune-PET procedures. The production of 89Zr and the impurities from proton irradiation of the 89Y target in a cyclotron was calculated with the Monte Carlo code MCNPX and the nuclear reaction code TALYS. The cumulated activities of the Zr isotopes were derived from real patient data in literature and the effective doses were estimated using the MIRD specific absorbed fraction formalism. The estimated effective dose from 89Zr is 0.5±0.2 mSv/MBq. The highest organ dose is 1.8±0.2 mSv/MBq in the liver. These values are in agreement with those reported in literature. The effective dose from 89mZr is about 0.2-0.3% of the 89Zr dose in the worst case. Since the ratio of 89mZr to 89Zr depends on the cooling time as well as the irradiation details, contaminant dose estimation is an important aspect in optimizing the cyclotron irradiation geometry, energy and time.

  6. New Morphine Analogs Produce Peripheral Antinociception within a Certain Dose Range of Their Systemic Administration.

    Science.gov (United States)

    Lackó, Erzsébet; Riba, Pál; Giricz, Zoltán; Váradi, András; Cornic, Laura; Balogh, Mihály; Király, Kornél; Csekő, Kata; Mousa, Shaaban A; Hosztafi, Sándor; Schäfer, Michael; Zádori, Zoltán Sándor; Helyes, Zsuzsanna; Ferdinandy, Péter; Fürst, Susanna; Al-Khrasani, Mahmoud

    2016-10-01

    Growing data support peripheral opioid antinociceptive effects, particularly in inflammatory pain models. Here, we examined the antinociceptive effects of subcutaneously administered, recently synthesized 14-O-methylmorphine-6-O-sulfate (14-O-MeM6SU) compared with morphine-6-O-sulfate (M6SU) in a rat model of inflammatory pain induced by an injection of complete Freund's adjuvant and in a mouse model of visceral pain evoked by acetic acid. Subcutaneous doses of 14-O-MeM6SU and M6SU up to 126 and 547 nmol/kg, respectively, produced significant and subcutaneous or intraplantar naloxone methiodide (NAL-M)-reversible antinociception in inflamed paws compared with noninflamed paws. Neither of these doses significantly affected thiobutabarbital-induced sleeping time or rat pulmonary parameters. However, the antinociceptive effects of higher doses were only partially reversed by NAL-M, indicating contribution of the central nervous system. In the mouse writhing test, 14-O-MeM6SU was more potent than M6SU after subcutaneous or intracerebroventricular injections. Both displayed high subcutaneous/intracerebroventricular ED50 ratios. The antinociceptive effects of subcutaneous 14-O-MeM6SU and M6SU up to 136 and 3043 nmol/kg, respectively, were fully antagonized by subcutaneous NAL-M. In addition, the test compounds inhibited mouse gastrointestinal transit in antinociceptive doses. Taken together, these findings suggest that systemic administration of the novel compound 14-O-MeM6SU similar to M6SU in specific dose ranges shows peripheral antinociception in rat and mouse inflammatory pain models without central adverse effects. These findings apply to male animals and must be confirmed in female animals. Therefore, titration of systemic doses of opioid compounds with limited access to the brain might offer peripheral antinociception of clinical importance. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  7. Volume dose ratios relevant for alanine dosimetry in small, 6 MV photon beams

    DEFF Research Database (Denmark)

    Cronholm, Rickard O.; Andersen, Claus Erik; Behrens, Claus F.

    2012-01-01

    therapy). To this end, we here present the results of a Monte Carlo simulation study with DOSRZnrc that investigated the influence of field and detector size for small 6 MV photon beams. The study focusses on doses averaged over the volume of the detector rather than point doses.The ratio of volume...... averaged doses to water (D¯W) and alanine (D¯det) was found to be approximately 1.025 for most situations studied, and a constant ratio is likely to be representative for many applications in radiation therapy. However, D¯W/D¯det was found to be as low as 0.9908 ± 0.0037 in situations where one might...... expect significant deviations from charged particle equilibrium (i.e. at shallow depths and when the field size was smaller than the range of the secondary electrons). These effects therefore need consideration when finite-size alanine dosimeters are used under such conditions....

  8. Quantitative biopharmaceutics classification system: the central role of dose/solubility ratio.

    Science.gov (United States)

    Rinaki, Eleni; Valsami, Georgia; Macheras, Panos

    2003-12-01

    To develop a quantitative biopharmaceutics drug classification system (QBCS) based on fundamental parameters controlling rate and extent of absorption. A simple absorption model that considers transit flow, dissolution, and permeation processes stochastically was used to illustrate the primary importance of dose/solubility ratio and permeability on drug absorption. Simple mean time considerations for dissolution, uptake, and transit were used to identify relationships between the extent of absorption and a drug's dissolution and permeability characteristics. The QBCS developed relies on a (permeability, dose/ solubility ratio) plane with cutoff points 2 x 10(-6)-10(-5) cm/s for the permeability and 0.5-1 (unitless) for the dose/solubility ratio axes. Permeability estimates, P(app) are derived from Caco-2 studies, and a constant intestinal volume content of 250 ml is used to express the dose/solubility ratio as a dimensionless quantity, q. A physiologic range of 250-500 ml was used to account for variability in the intestinal volume. Drugs are classified into the four quadrants of the plane around the cutoff points according to their P(app), q values, establishing four drug categories. i.e., I (P(app) > 10(-5) cm/s, q 10(-5) cm/s, q > 1), III (P(app) 1). A region for borderline drugs (2 x 10(-6) biopharmaceutical properties, permeability, and dose/solubility ratio. Semiquantitative predictions for the extent of absorption are essentially based on these drug properties, which either determine or are strongly related to the in vivo kinetics of drug dissolution and intestinal wall permeation.

  9. Dose ratio proton radiography using the proximal side of the Bragg peak.

    Science.gov (United States)

    Doolan, P J; Royle, G; Gibson, A; Lu, H-M; Prieels, D; Bentefour, E H

    2015-04-01

    In recent years, there has been a movement toward single-detector proton radiography, due to its potential ease of implementation within the clinical environment. One such single-detector technique is the dose ratio method in which the dose maps from two pristine Bragg peaks are recorded beyond the patient. To date, this has only been investigated on the distal side of the lower energy Bragg peak, due to the sharp falloff. The authors investigate the limits and applicability of the dose ratio method on the proximal side of the lower energy Bragg peak, which has the potential to allow a much wider range of water-equivalent thicknesses (WET) to be imaged. Comparisons are made with the use of the distal side of the Bragg peak. Using the analytical approximation for the Bragg peak, the authors generated theoretical dose ratio curves for a range of energy pairs, and then determined how an uncertainty in the dose ratio would translate to a spread in the WET estimate. By defining this spread as the accuracy one could achieve in the WET estimate, the authors were able to generate lookup graphs of the range on the proximal side of the Bragg peak that one could reliably use. These were dependent on the energy pair, noise level in the dose ratio image and the required accuracy in the WET. Using these lookup graphs, the authors investigated the applicability of the technique for a range of patient treatment sites. The authors validated the theoretical approach with experimental measurements using a complementary metal oxide semiconductor active pixel sensor (CMOS APS), by imaging a small sapphire sphere in a high energy proton beam. Provided the noise level in the dose ratio image was 1% or less, a larger spread of WETs could be imaged using the proximal side of the Bragg peak (max 5.31 cm) compared to the distal side (max 2.42 cm). In simulation, it was found that, for a pediatric brain, it is possible to use the technique to image a region with a square field equivalent size

  10. Changing behavior within session: cyclicity and perseverance produced by varying the minimum ratio of a variable-ratio schedule.

    OpenAIRE

    Andrzejewski, M E; Field, D P; Hineline, P N

    2001-01-01

    Four pigeons repeatedly chose between a fixed-ratio (FR) 20 and a variable-ratio (VR) 40 schedule of reinforcement, in which the minimum ratio of the VR cycled within each session. The minimum ratio ascended and descended (ASCDESC), descended and ascended (DESCASC), or remained constant (unchanging). In Phase 1, 2 birds (Group 1) were exposed to ASCDESC series and 2 birds (Group 2) were exposed to the DESCASC series. Choice proportions changed with the cycling minimum ratio for Group 2 but no...

  11. Ratio

    Science.gov (United States)

    Webster, Nathan A. S.; Pownceby, Mark I.; Madsen, Ian C.; Studer, Andrew J.; Manuel, James R.; Kimpton, Justin A.

    2014-12-01

    Effects of basicity, B (CaO:SiO2 ratio) on the thermal range, concentration, and formation mechanisms of silico-ferrite of calcium and aluminum (SFCA) and SFCA-I iron ore sinter bonding phases have been investigated using an in situ synchrotron X-ray diffraction-based methodology with subsequent Rietveld refinement-based quantitative phase analysis. SFCA and SFCA-I phases are the key bonding materials in iron ore sinter, and improved understanding of the effects of processing parameters such as basicity on their formation and decomposition may assist in improving efficiency of industrial iron ore sintering operations. Increasing basicity significantly increased the thermal range of SFCA-I, from 1363 K to 1533 K (1090 °C to 1260 °C) for a mixture with B = 2.48, to ~1339 K to 1535 K (1066 °C to 1262 °C) for a mixture with B = 3.96, and to ~1323 K to 1593 K (1050 °C to 1320 °C) at B = 4.94. Increasing basicity also increased the amount of SFCA-I formed, from 18 wt pct for the mixture with B = 2.48 to 25 wt pct for the B = 4.94 mixture. Higher basicity of the starting sinter mixture will, therefore, increase the amount of SFCA-I, considered to be more desirable of the two phases. Basicity did not appear to significantly influence the formation mechanism of SFCA-I. It did, however, affect the formation mechanism of SFCA, with the decomposition of SFCA-I coinciding with the formation of a significant amount of additional SFCA in the B = 2.48 and 3.96 mixtures but only a minor amount in the highest basicity mixture. In situ neutron diffraction enabled characterization of the behavior of magnetite after melting of SFCA produced a magnetite plus melt phase assemblage.

  12. Producing Gas-Oil Ratio Performance of Conventional and Unconventional Reservoirs

    OpenAIRE

    Lei, Guowen

    2012-01-01

    This study presents a detailed analysis of producing gas-oil ratio performance characteristics from conventional reservoir to unconventional reservoir. Numerical simulations of various reservoir fluid systems are included for comparison. In a wide sense of the word, the term of unconventional reservoir is including tight gas sand, coal bed methane, gas hydrate deposits, heavy oil gas shale and etc. In this study we specify the unconventional reservoir to only mean the low and ultra low permea...

  13. Changing behavior within session: cyclicity and perseverance produced by varying the minimum ratio of a variable-ratio schedule.

    Science.gov (United States)

    Andrzejewski, M E; Field, D P; Hineline, P N

    2001-03-01

    Four pigeons repeatedly chose between a fixed-ratio (FR) 20 and a variable-ratio (VR) 40 schedule of reinforcement, in which the minimum ratio of the VR cycled within each session. The minimum ratio ascended and descended (ASCDESC), descended and ascended (DESCASC), or remained constant (unchanging). In Phase 1, 2 birds (Group 1) were exposed to ASCDESC series and 2 birds (Group 2) were exposed to the DESCASC series. Choice proportions changed with the cycling minimum ratio for Group 2 but not for Group 1. In Phase 2, Group 1 subjects were exposed to the DESCASC series and Group 2 subjects were exposed to the unchanging condition. Although Group 1's choice proportions appeared to be undifferentiated in Phase 2, Group 2's choice proportions continued to cycle for more than 100 sessions. Group 2 subjects were then moved to the ASCDESC series in the third phase, and choice proportions cycled with the minimum ratio as in the first phase. The descending portion of the series was the more powerful determinant of cyclicity. Response rates also changed with the minimum component ratio, a finding that goes against the claim of universality of a rise-and-fall within-session pattern of responding. That preference varied despite the constancy of the average ratio requirement suggests nonlinear averaging in quantitatively representing a variable schedule's value. The strong perseverance observed also lends support to a growing body of literature on history effects.

  14. Electron dose dependence of signal-to-noise ratio, atom contrast and resolution in transmission electron microscope images

    International Nuclear Information System (INIS)

    Lee, Z.; Rose, H.; Lehtinen, O.; Biskupek, J.; Kaiser, U.

    2014-01-01

    In order to achieve the highest resolution in aberration-corrected (AC) high-resolution transmission electron microscopy (HRTEM) images, high electron doses are required which only a few samples can withstand. In this paper we perform dose-dependent AC-HRTEM image calculations, and study the dependence of the signal-to-noise ratio, atom contrast and resolution on electron dose and sampling. We introduce dose-dependent contrast, which can be used to evaluate the visibility of objects under different dose conditions. Based on our calculations, we determine optimum samplings for high and low electron dose imaging conditions. - Highlights: • The definition of dose-dependent atom contrast is introduced. • The dependence of the signal-to-noise ratio, atom contrast and specimen resolution on electron dose and sampling is explored. • The optimum sampling can be determined according to different dose conditions

  15. Induction of inherited sterility and sex ratio distribution due to exposure to substerilising doses of gamma radiation in cotton bollworm Earias vittella fabricius

    International Nuclear Information System (INIS)

    Tamhankar, A.J.; Shantharam, K.

    2005-01-01

    Substerilising doses of gamma radiation induced inherited sterility and sex ratio distortion in the cotton bollworm Earias vittella fabricius. Adults irradiated with 75 Gy and self-crossed, provided sterile F 1 adults, suitable for direct use in sterile insect technique (SIT). In case of 50 Gy, the F 1 adults, when backcrossed, produced F 2 progeny with sex ratio in favour of females (1: >3). With 25 Gy, a sex ratio distortion was recorded in F 1 (1 male: 2.25 females) and self-crossing of F 1 resulted in progeny with a sex ratio of 3:1. Backcrossing of the F 1 female produced F 2 progeny with a sex ratio of 1:5. These results have implications in improving cost/benefit ratio of SIT for this species. (author)

  16. Volume dose ratios relevant for alanine dosimetry in small, 6 MV photon beams

    International Nuclear Information System (INIS)

    Cronholm, Rickard O.; Andersen, Claus E.; Behrens, Claus F.; Helt-Hansen, Jakob

    2012-01-01

    The overall objective of this work is to establish alanine dosimetry for traceable measurements in clinical radiotherapy beams, in particular for non-reference situations such as small field sizes and composite beam delivery (e.g. intensity modulated radiotherapy and volumetric modulated arc therapy). To this end, we here present the results of a Monte Carlo simulation study with DOSRZnrc that investigated the influence of field and detector size for small 6 MV photon beams. The study focusses on doses averaged over the volume of the detector rather than point doses. The ratio of volume averaged doses to water (D ¯ W ) and alanine (D ¯ det ) was found to be approximately 1.025 for most situations studied, and a constant ratio is likely to be representative for many applications in radiation therapy. However, D ¯ W /D ¯ det was found to be as low as 0.9908 ± 0.0037 in situations where one might expect significant deviations from charged particle equilibrium (i.e. at shallow depths and when the field size was smaller than the range of the secondary electrons). These effects therefore need consideration when finite-size alanine dosimeters are used under such conditions.

  17. Compressibility and resiliency properties of wilton type woven carpets produced with different fiber blend ratio

    Science.gov (United States)

    Osman, B.; Esin, S.; Sıdıka Ziba, O.

    2017-10-01

    Carpet is a textile structure that composed of three components: warp (stuffer and chain warp), weft and pile yarns. These textile products are used for areas which will stand up to the use of home, hotel, work place etc. Furthermore, the capable of carpets are related to it’s especially pile performance during use in various areas. During usage, carpets made from various type of raw materials of pile yarn also acts differently that these differentiate determines carpet performance, as well.This study was focused on the compression and resilience behaviour of carpet composed of 100% viscose and 100% acrylic pile yarns and blended pile yarns of blend ratios, 80%/20%, 50%/50% and 20%/80% viscose/acrylic. During the yarn production process, all spinning conditions were kept constant in order to eliminate the yarn production parameters. Five different types of wilton face to face carpet samples were produced from these yarns at the same pile height and pile density on Van de Wiele carpet weaving machine at 110 picks/min machine speed and 1/1 V carpet construction. Compressibility properties of carpets were examined whether blend ratio was statistically significant on carpet resilience or not. The behaviour of pile yarns under pressure is important that leads to understand the growth characteristic which is exposed to decrease and increase loadings during usage of carpet made from these yarns. Results indicated that blend ratio of pile yarns have significance effect on compression behaviour of carpet samples.

  18. Optimization of HNA etching parameters to produce high aspect ratio solid silicon microneedles

    International Nuclear Information System (INIS)

    Hamzah, A A; Yeop Majlis, B; Yunas, J; Dee, C F; Abd Aziz, N; Bais, B

    2012-01-01

    High aspect ratio solid silicon microneedles with a concave conic shape were fabricated. Hydrofluoric acid–nitric acid–acetic acid (HNA) etching parameters were characterized and optimized to produce microneedles that have long and narrow bodies with smooth surfaces, suitable for transdermal drug delivery applications. The etching parameters were characterized by varying the HNA composition, the optical mask's window size, the etching temperature and bath agitation. An L9 orthogonal Taguchi experiment with three factors, each having three levels, was utilized to determine the optimal fabrication parameters. Isoetch contours for HNA composition with 0% and 10% acetic acid concentrations were presented and a high nitric acid region was identified to produce microneedles with smooth surfaces. It is observed that an increase in window size indiscriminately increases the etch rate in both the vertical and lateral directions, while an increase in etching temperature beyond 35 °C causes the etching to become rapid and uncontrollable. Bath agitation and sample placement could be manipulated to achieve a higher vertical etch rate compared to its lateral counterpart in order to construct high aspect ratio microneedles. The Taguchi experiment performed suggests that a HNA composition of 2:7:1 (HF:HNO 3 :CH 3 COOH), window size of 500 µm and agitation rate of 450 RPM are optimal. Solid silicon microneedles with an average height of 159.4 µm, an average base width of 110.9 µm, an aspect ratio of 1.44, and a tip angle and diameter of 19.2° and 0.38 µm respectively were successfully fabricated. (paper)

  19. Inclusive semileptonic branching ratios of b hadrons produced in Z decays

    CERN Document Server

    Heister, A.; Barate, R.; De Bonis, I.; Decamp, D.; Goy, C.; Lees, J.P.; Merle, E.; Minard, M.N.; Pietrzyk, B.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, L.; Grauges, E.; Martinez, M.; Merino, G.; Miquel, R.; Mir, L.M.; Pacheco, A.; Ruiz, H.; Colaleo, A.; Creanza, D.; De Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Azzurri, P.; Boix, G.; Buchmuller, O.; Cattaneo, M.; Cerutti, F.; Clerbaux, B.; Dissertori, G.; Drevermann, H.; Forty, R.W.; Frank, M.; Greening, T.C.; Hansen, J.B.; Harvey, John; Janot, P.; Jost, B.; Kado, M.; Mato, P.; Moutoussi, A.; Ranjard, F.; Rolandi, Gigi; Schlatter, D.; Schneider, O.; Tejessy, W.; Teubert, F.; Tournefier, E.; Ward, J.; Ajaltouni, Z.; Badaud, F.; Falvard, A.; Gay, P.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.C.; Pallin, D.; Perret, P.; Podlyski, F.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Nilsson, B.S.; Waananen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J.C.; Rouge, A.; Rumpf, M.; Swynghedauw, M.; Verderi, M.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Chiarella, V.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G.P.; Passalacqua, L.; Pepe-Altarelli, M.; Spagnolo, P.; Halley, A.W.; Lynch, J.G.; Negus, P.; O'Shea, V.; Raine, C.; Thompson, A.S.; Wasserbaech, S.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E.E.; Putzer, A.; Sommer, J.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Dornan, P.J.; Girone, M.; Marinelli, N.; Sedgbeer, J.K.; Thompson, J.C.; Ghete, V.M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C.K.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Pearson, M.R.; Robertson, N.A.; Giehl, I.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.G.; Wachsmuth, H.; Zeitnitz, C.; Bonissent, A.; Carr, J.; Coyle, P.; Leroy, O.; Payre, P.; Rousseau, D.; Talby, M.; Aleppo, M.; Ragusa, F.; David, A.; Dietl, H.; Ganis, G.; Huttmann, K.; Lutjens, G.; Mannert, C.; Manner, W.; Moser, H.G.; Settles, R.; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, P.; Jacholkowska, A.; Lefrancois, J.; Veillet, J.J.; Videau, I.; Yuan, C.; Bagliesi, Giuseppe; Boccali, T.; Foa, L.; Giammanco, A.; Giassi, A.; Ligabue, F.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciaba, A.; Sguazzoni, G.; Tenchini, R.; Venturi, A.; Verdini, P.G.; Blair, G.A.; Cowan, G.; Green, M.G.; Medcalf, T.; Misiejuk, A.; Strong, J.A.; Teixeira-Dias, P.; Von Wimmersperg-Toeller, J.H.; Clifft, R.W.; Edgecock, T.R.; Norton, P.R.; Tomalin, I.R.; Bloch-Devaux, Brigitte; Colas, P.; Emery, S.; Kozanecki, W.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.F.; Roussarie, A.; Schuller, J.P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Konstantinidis, N.; Litke, A.M.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Lehto, M.; Thompson, L.F.; Affholderbach, K.; Boehrer, Armin; Brandt, S.; Grupen, C.; Ngac, A.; Prange, G.; Sieler, U.; Giannini, G.; Rothberg, J.; Armstrong, S.R.; Cranmer, K.; Elmer, P.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Hayes, O.J.; Hu, H.; Jin, S.; Kile, J.; McNamara, P.A., III; Nielsen, J.; Orejudos, W.; Pan, Y.B.; Saadi, Y.; Scott, I.J.; Walsh, J.; Wu, Sau Lan; Wu, X.; Zobernig, G.

    2002-01-01

    A measurement of the inclusive semileptonic branching ratios of b hadrons produced in Z decay is presented, using four million hadronic events collected by the ALEPH detector from 1991 to 1995. Electrons and muons are selected opposite to b-tagged hemispheres. Two different methods are explored to distinguish the contributions from direct $\\bl$ and cascade $\\bcl$ dec ays to the total lepton yield. One is based on the lepton transverse momentum spectrum, the other makes use of the correlation between the charge of the lepton and charge estimators built from tracks in the opposite hemisphere of the event. The latter method reduces the dependence on the modelling of semileptonic b decays. The results obtained by averaging the two techniques are BR(b->l) = 0.1070 +- 0.0010 +- 0.0023 +- 0.0026 BR(b->c->l) = 0.0818 +- 0.0015 +- 0.0022 + 0.0022 -0.0014

  20. Measurement and properties of the dose-area product ratio in external small-beam radiotherapy

    Science.gov (United States)

    Niemelä, Jarkko; Partanen, Mari; Ojala, Jarkko; Sipilä, Petri; Björkqvist, Mikko; Kapanen, Mika; Keyriläinen, Jani

    2017-06-01

    In small-beam radiation therapy (RT) the measurement of the beam quality parameter, i.e. the tissue-phantom ratio or TPR20,10, using a conventional point detector is a challenge. To obtain reliable results, one has to consider potential sources of error, including volume averaging and adjustment of the point detector into the narrow beam. To overcome these challenges, a different type of beam quality parameter in small beams was studied, namely the dose-area product ratio, or DAPR20,10. With this method, the measurement of a dose-area product (DAP) using a large-area plane-parallel chamber (LAC) eliminates the uncertainties in detector positioning and volume averaging that are present when using a point detector. In this study, the properties of the DAPR20,10 of a cone-collimated 6 MV photon beam were investigated using Monte Carlo (MC) calculations and the obtained values were compared to measurements obtained using two LAC detectors, PTW Type 34073 and PTW Type 34070. In addition, the possibility of determining the DAP using EBT3 film and a Razor diode detector was studied. The determination of the DAPR20,10 value was found to be feasible in external small-beam radiotherapy using cone-collimated beams with diameters from 4-40 mm, based on the results of the two LACs, the MC calculations and the Razor diode. The measurements indicated a constant DAPR20,10 value for fields 20-40 mm in diameter, with a maximum relative change of 0.6%, but an increase of 7.0% for fields from 20-4 mm in diameter for the PTW Type 34070 chamber. Simulations and measurements showed an increase of DAPR20,10 with increasing LAC size or dose integral area for the studied 4-40 mm cone-collimated 6 MV photon beams. This has the consequence that there should be a reference to the size of the used LAC active area or the DAP integration area with the reported DAPR20,10 value.

  1. Measurement and properties of the dose-area product ratio in external small-beam radiotherapy.

    Science.gov (United States)

    Niemelä, Jarkko; Partanen, Mari; Ojala, Jarkko; Sipilä, Petri; Björkqvist, Mikko; Kapanen, Mika; Keyriläinen, Jani

    2017-06-21

    In small-beam radiation therapy (RT) the measurement of the beam quality parameter, i.e. the tissue-phantom ratio or TPR 20,10 , using a conventional point detector is a challenge. To obtain reliable results, one has to consider potential sources of error, including volume averaging and adjustment of the point detector into the narrow beam. To overcome these challenges, a different type of beam quality parameter in small beams was studied, namely the dose-area product ratio, or DAPR 20,10 . With this method, the measurement of a dose-area product (DAP) using a large-area plane-parallel chamber (LAC) eliminates the uncertainties in detector positioning and volume averaging that are present when using a point detector. In this study, the properties of the DAPR 20,10 of a cone-collimated 6 MV photon beam were investigated using Monte Carlo (MC) calculations and the obtained values were compared to measurements obtained using two LAC detectors, PTW Type 34073 and PTW Type 34070. In addition, the possibility of determining the DAP using EBT3 film and a Razor diode detector was studied. The determination of the DAPR 20,10 value was found to be feasible in external small-beam radiotherapy using cone-collimated beams with diameters from 4-40 mm, based on the results of the two LACs, the MC calculations and the Razor diode. The measurements indicated a constant DAPR 20,10 value for fields 20-40 mm in diameter, with a maximum relative change of 0.6%, but an increase of 7.0% for fields from 20-4 mm in diameter for the PTW Type 34070 chamber. Simulations and measurements showed an increase of DAPR 20,10 with increasing LAC size or dose integral area for the studied 4-40 mm cone-collimated 6 MV photon beams. This has the consequence that there should be a reference to the size of the used LAC active area or the DAP integration area with the reported DAPR 20,10 value.

  2. Antiproton Radiotherapy Peripheral Dose from Secondary Neutrons produced in the Annihilation of Antiprotons in the Target

    CERN Document Server

    Fahimian, Benjamin P; Keyes, Roy; Bassler, Niels; Iwamoto, Keisuke S; Zankl, Maria; Holzscheiter, Michael H

    2009-01-01

    The AD-4/ACE collaboration studies the biological effects of antiprotons with respect to a possible use of antiprotons in cancer therapy. In vitro experiments performed by the collaboration have shown an enhanced biological effectiveness for antiprotons relative to protons. One concern is the normal tissue dose resulting from secondary neutrons produced in the annihilation of antiprotons on the nucleons of the target atoms. Here we present the first organ specific Monte Carlo calculations of normal tissue equivalent neutron dose in antiproton therapy through the use of a segmented CT-based human phantom. The MCNPX Monte Carlo code was employed to quantify the peripheral dose for a cylindrical spread out Bragg peak representing a treatment volume of 1 cm diameter and 1 cm length in the frontal lobe of a segmented whole-body phantom of a 38 year old male. The secondary neutron organ dose was tallied as a function of energy and organ.

  3. Carbon and nitrogen isotope ratios of factory-produced RDX and HMX.

    Science.gov (United States)

    Howa, John D; Lott, Michael J; Chesson, Lesley A; Ehleringer, James R

    2014-07-01

    RDX and HMX are explosive compounds commonly used by the military and also occasionally associated with acts of terrorism. The isotopic characterization of an explosive can be a powerful approach to link evidence to an event or an explosives cache. We sampled explosive products and their reactants from commercial RDX manufacturers that used the direct nitration and/or the Bachmann synthesis process, and then analyzed these materials for carbon and nitrogen isotope ratios. For manufacturers using the Bachmann process, RDX (13)C enrichment relative to the hexamine substrate was small (+0.9‰) compared to RDX produced using the direct nitration process (+8.2‰ to +12.0‰). RDX (15)N depletion relative to the nitrogen-containing substrates (-3.6‰) was smaller in the Bachmann process than in the direct nitration process (-12.6‰ to -10.6‰). The sign and scale of these differences agree with theorized mechanisms of mass-dependent fractionation. We also examined the isotopic relationship between RDX and HMX isolated from explosive samples. The δ(13)C and δ(15)N values of RDX generally matched those of the HMX with few exceptions, most notably from a manufacturer known to make RDX using two different synthesis processes. The range in δ(13)C values of RDX in a survey of 100 samples from 12 manufacturers spanned 33‰ while the range spanned by δ(15)N values was 26‰; these ranges were much greater than any previously published observations. Understanding the relationship between products and reactants further explains the observed variation in industrially manufactured RDX and can be used as a diagnostic tool to analyze explosives found at a crime scene. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Cannabidiol reverses the reduction in social interaction produced by low dose Delta(9)-tetrahydrocannabinol in rats.

    Science.gov (United States)

    Malone, Daniel Thomas; Jongejan, Dennis; Taylor, David Alan

    2009-08-01

    While Delta(9)-tetrahydrocannabinol (THC) is the main psychoactive constituent of the cannabis plant, a non-psychoactive constituent is cannabidiol (CBD). CBD has been implicated as a potential treatment of a number of disorders including schizophrenia and epilepsy and has been included with THC in a 1:1 combination for the treatment of conditions such as neuropathic pain. This study investigated the effect of THC and CBD, alone or in combination, on some objective behaviours of rats in the open field. Pairs of rats were injected with CBD or vehicle followed by THC or vehicle and behaviour in the open field was assessed for 10 min. In vehicle pretreated rats THC (1 mg/kg) significantly reduced social interaction between rat pairs. Treatment with CBD had no significant effect alone, but pretreatment with CBD (20 mg/kg) reversed the THC-induced decreases in social interaction. A higher dose of THC (10 mg/kg) produced no significant effect on social interaction. However, the combination of high dose CBD and high dose THC significantly reduced social interaction between rat pairs, as well as producing a significant decrease in locomotor activity. This data suggests that CBD can reverse social withdrawal induced by low dose THC, but the combination of high dose THC and CBD impairs social interaction, possibly by decreasing locomotor activity.

  5. Impact of cytochrome p450 3A5 genetic polymorphism on tacrolimus doses and concentration-to-dose ratio in renal transplant recipients.

    Science.gov (United States)

    Thervet, Eric; Anglicheau, Dany; King, Barry; Schlageter, Marie-Hélène; Cassinat, Bruno; Beaune, Philippe; Legendre, Christophe; Daly, Ann K

    2003-10-27

    Tacrolimus pharmacokinetic characteristics vary greatly among individuals. Tacrolimus is a substrate of cytochrome p450 (CYP), of subfamily CYP3A. CYP3A activity is the sum of the activities of the family of CYP3A genes, including CYP3A5. Subjects with the CYP3A5*1/*1 genotype express large amounts of CYP3A5. Heterozygotes (genotype CYP3A5*1/*3) also express the enzyme. We postulated that CYP3A5 polymorphism is associated with tacrolimus pharmacokinetic variations. CYP3A5 genotype was evaluated in 80 renal transplant recipients and correlated with the daily tacrolimus dose and concentration-to-dose ratio. The frequency of the homozygous CYP3A5*1 genotype (CYP3A5*1/*1) was 5%, and 11% of subjects were heterozygous (CYP3A5*1/*3). The mean doses required to obtain the targeted concentration-to-dose ratio were significantly lower in patients with the CYP3A5*1/*1 genotype. Determination of CYP3A5 genotype is predictive of the dose of tacrolimus in renal transplant recipients and may help to determine the initial daily dose needed by individual patients for adequate immunosuppression without excess nephrotoxicity.

  6. Does low-dose CCK-8 injection produce abdominal pain in 'truly normal' individuals?

    International Nuclear Information System (INIS)

    Ramsay, S.; Webb, B.; Hille, N.

    1999-01-01

    Full text: The development of abdominal pain following cholecystokinin (CCK) injection is not specific for biliary disease. Patients can develop abdominal pain with CCK during hepatobiliary studies and have normal gallbladder function. Does this non-biliary pain indicate pathology? High doses of CCK induce pain in functional bowel syndromes, but may also produce pain in normals. Pain is less common at lower CCK doses, and hence may be more significant. This study aimed to determine the rate at which the low dose of CCK used in hepatobiliary scans causes abdominal pain and other side-effects in 'truly normal' individuals. Some preliminary results of CCK-induced pain in gastro-oesophageal reflux (GOR) patients are also discussed. Six 'truly normal' subjects were studied. 'Truly normal' was defined as: no current history of abdominal pain; no biliary or gallbladder disease; no significant GIT pathology; not currently on medication designed to be pharmacologically active in the GIT. Each patient was given an intravenous dose of 0.01 μg-kg -1 of CCK8 over 3 min, and side-effects were recorded for 30 min. No subject had abdominal pain. Two developed nausea, 1 moderate and 1 mild. An identical dose of CCK was given to 2 patients with endoscopically proven GOR. Anti-reflux medication had been ceased for 12 h. After CCK, 1 patient developed typical 'reflux' pain and 1 was asymptomatic. In conclusion, none of our 'truly normal' patients had abdominal pain with low-dose CCK. This suggests that patients developing pain following injection of this dose of CCK are indeed abnormal. The literature infers these patients may have irritable bowel syndrome; however, this hypothesis is complicated by our preliminary results indicating that CCK can reproduce pain in some patients with GOR

  7. Differential association of fluconazole dose and dose/MIC ratio with mortality in patients with Candida albicans and non-albicans bloodstream infection.

    Science.gov (United States)

    Brosh-Nissimov, T; Ben-Ami, R

    2015-11-01

    Targeting fluconazole therapy to achieve predefined pharmacodynamic goals has been suggested as a means of optimizing the treatment of patients with candidaemia. However, data regarding species-specific dosing targets are inconclusive. We retrospectively analysed a cohort of 75 adult patients with Candida bloodstream infection (BSI) who received initial treatment with fluconazole for ≥48 h (36 Candida albicans and 39 non-albicans Candida (NAC)). Fluconazole dose, the dose/MIC ratio and the 24-h area under the concentration-time curve (AUC24)/MIC ratio were determined for each patient, and classification and regression tree analysis was used to determine breakpoints for significant interactions with 30-day survival. Both fluconazole exposure parameters and patient-related and disease-related variables were assessed in univariable and multivariable survival models. The crude 30-day mortality rate was 32% (44% and 21% for C. albicans and NAC, respectively). An average fluconazole dose of >200 mg/day, a dose/MIC ratio of >400 and an AUC24/MIC ratio of >400 were associated with a higher 30-day survival rate and better microbiological response in patients with C. albicans BSI but not in those with NAC BSI. Baseline chronic kidney disease was a risk factor for fluconazole underdosing and mortality. Severity of sepsis (Sequential Organ Failure Assessment score) was the only significant predictor of death in patients with NAC BSI. We conclude that, although pharmacodynamic target-directed fluconazole dosing may help to optimize outcomes for patients with C. albicans BSI, additional studies are needed to define the role of fluconazole in the treatment of NAC BSI. Copyright © 2015 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  8. Photon Dose Enhancement Ratio at the Transition Region of Dissimilar Media

    Directory of Open Access Journals (Sweden)

    Maan S. Al-Arif

    2014-12-01

    Full Text Available Accurate measurement was carried out for the dose gradient in Teflon irradiated with filtered X-ray spectra having effective energies of 40 keV and 55 keV when in contact with aluminum, titanium, copper, and tin. At low photon energies, the interface region is only extended for about 10 microns from the interface, therefore, ultra-thin LiF/Teflon discs of the order of 3 microns thick was developed and used to measure directly the dose gradient in Teflon. Due to the relatively large slope of the depth dose curves near the interfaces, a displacement correction factor was introduced to determine the effective measuring point of the detector. A fitting exponential formula is suggested and used to estimate the dose gradient for Bone-Teflon interface. The interface dose for Bone-Teflon is 3.8 times the equilibrium dose at 70 KV, while it is about 3.1 at 100 KV.

  9. Liquefied Residue of Kenaf Core Wood Produced at Different Phenol-Kenaf Ratio

    International Nuclear Information System (INIS)

    Saiful Bahari Bakarudin; Sarani Zakaria; Chia, C.H.; Jani, S.M.

    2012-01-01

    Liquefactions of kenaf core wood were carried out at different phenol-kenaf (P/ k) ratios. Characterizations of kenaf core wood liquefied residue were carried out to measure the degree of liquefaction. This provides a new approach to understand some fundamental aspects of the liquefaction reaction. Functional groups on the raw kenaf core wood and liquefied residue were examined using Fourier transform infrared spectroscopy (FTIR). The crystallinity index of the kenaf wood liquefied residue, which represents crystallinity changes of the cellulose component after the liquefaction process, was studied using X-ray diffraction (XRD). The surface morphology of the wood residue was observed using scanning electron microscopy (SEM). The thermal behavior of the residues was analyzed using thermogravimetric analysis (TGA). Abroad peak around 3450-3400 cm -1 representing OH stretching in lignin start to disappear as P/K ratio increases. The results showed that the higher the P/K ratio the greater the liquefaction of the lignin component in the kenaf core wood. The crystallinity index (CrI) on the kenaf liquefied residues increased with the increase in P/K ratio. SEM images showed that the small fragments attached on the liquefied kenaf residue surface were gradually removed as the P/K ratio was increased from 1.5/ 1.0 to 2.5/ 1.0, which is mainly attributed to the greater chemical penetration toward reactive site of the kenaf fibres. Residue content decreased as the P/K ratio increased from 1.5/ 1.0 to 2.5/ 1.0. TGA results showed the increase of heat resistance in the residue as the P/K ratio was increased. (author)

  10. Dose properties of x-ray beams produced by laser-wakefield-accelerated electrons

    International Nuclear Information System (INIS)

    Kainz, K K; Hogstrom, K R; Antolak, J A; Almond, P R; Bloch, C D

    2005-01-01

    Given that laser wakefield acceleration (LWFA) has been demonstrated experimentally to accelerate electron beams to energies beyond 25 MeV, it is reasonable to assess the ability of existing LWFA technology to compete with conventional radiofrequency linear accelerators in producing electron and x-ray beams for external-beam radiotherapy. We present calculations of the dose distributions (off-axis dose profiles and central-axis depth dose) and dose rates of x-ray beams that can be produced from electron beams that are generated using state-of-the-art LWFA. Subsets of an LWFA electron energy distribution were propagated through the treatment head elements (presuming an existing design for an x-ray production target and flattening filter) implemented within the EGSnrc Monte Carlo code. Three x-ray energy configurations (6 MV, 10 MV and 18 MV) were studied, and the energy width ΔE of the electron-beam subsets varied from 0.5 MeV to 12.5 MeV. As ΔE increased from 0.5 MeV to 4.5 MeV, we found that the off-axis and central-axis dose profiles for x-rays were minimally affected (to within about 3%), a result slightly different from prior calculations of electron beams broadened by scattering foils. For ΔE of the order of 12 MeV, the effect on the off-axis profile was of the order of 10%, but the central-axis depth dose was affected by less than 2% for depths in excess of about 5 cm beyond d max . Although increasing ΔE beyond 6.5 MeV increased the dose rate at d max by more than 10 times, the absolute dose rates were about 3 orders of magnitude below those observed for LWFA-based electron beams at comparable energies. For a practical LWFA-based x-ray device, the beam current must be increased by about 4-5 orders of magnitude. (note)

  11. Carbon content and C:N ratio of transparent exopolymeric particles (TEP) produced by bubbling exudates of diatoms

    DEFF Research Database (Denmark)

    Mari, Xavier

    1999-01-01

    The carbon content of transparent exopolymeric particles (TEP) was measured in the laboratory in particles produced by bubbling exudates of the diatom Thalassiosira weissflogii, grown under nitrogen non-limited conditions (N:P = 7). The carbon content of these particles (TEP-C) appears to vary...... for dissolved organic carbon in coastal seas. The carbon to nitrogen ratio of TEP was measured from particles formed by bubbling exudates of the diatoms T. weissflogii, Skeletonema costatum, Chaetoceros neogracile and C. affinis. Each of these diatom species was grown under various N:P ratios, from N......-non-limited to N-limited conditions. While the C:N ratio of the diatom cells grown under N-limited conditions was high (C:N >= 14), the TEP aggregates formed by coagulation of the extracellular release produced by these cells exhibited a C:N ratio relatively constant (C:N = 7.3 ± 2.6) and apparently independent...

  12. A novel dose-volume metric for optimizing therapeutic ratio through fractionation: retrospective analysis of lung cancer treatments.

    Science.gov (United States)

    Keller, Harald; Hope, Andrew; Meier, Gabriel; Davison, Matt

    2013-08-01

    To explore the potential of a novel dose-volume based metric to assist in the selection of optimal fractionation schedules for lung cancer patients. Selecting the dose per fraction that maximizes the therapeutic ratio via a linear-quadratic effect on normal tissue complication probability and tumor cell survival is an optimization problem. The mathematical solution reveals that the optimal fractionation schedule is determined by a generalized dose ratio between the normal tissue and the tumor, here termed the bifurcation number B, that can be derived from the dose-volume histogram of the normal tissue. The bifurcation number characterizes the volume effect of a normal tissue and its dependency on the fractionation schedule. The clinical relevance of the bifurcation number was evaluated in 46 patients previously treated for nonsmall cell lung cancer (NSCLC) according to various fractionation protocols. Bifurcation numbers were computed for both lung and esophagus as the normal tissues. The value of the bifurcation number determines whether the volume effect reverses the traditional radiobiological advantage of small dose per fraction for the normal tissue. If B is smaller than the ratio of alpha/beta ratios between normal tissue and tumor, then a single fraction is optimal; otherwise the optimal treatment is an infinite number of doses (hence the name "bifurcation" number). These fractionation schedules correspond clinically to hypo- and standard/hyperfractionation, respectively. Compared with traditional dose-volume metrics, the bifurcation number is a unitless ratio and independent of dose fractionation. The B-numbers derived from the clinical treatment plans are also strongly consistent with historically prescribed clinical fractionation protocols for NSCLC treatments. The B-numbers for esophagus and lung for all patients receiving a high dose per fraction protocol (>7.5 Gy/fraction) were all smaller than the B-numbers for the patients receiving standard 2 Gy

  13. Theoretical analysis of the dose dependence of the oxygen enhancement ratio and its relevance for clinical applications

    International Nuclear Information System (INIS)

    Wenzl, Tatiana; Wilkens, Jan J

    2011-01-01

    The increased resistance of hypoxic cells to ionizing radiation is usually believed to be the primary reason for treatment failure in tumors with oxygen-deficient areas. This oxygen effect can be expressed quantitatively by the oxygen enhancement ratio (OER). Here we investigate theoretically the dependence of the OER on the applied local dose for different types of ionizing irradiation and discuss its importance for clinical applications in radiotherapy for two scenarios: small dose variations during hypoxia-based dose painting and larger dose changes introduced by altered fractionation schemes. Using the widespread Alper-Howard-Flanders and standard linear-quadratic (LQ) models, OER calculations are performed for T1 human kidney and V79 Chinese hamster cells for various dose levels and various hypoxic oxygen partial pressures (pO2) between 0.01 and 20 mmHg as present in clinical situations in vivo. Our work comprises the analysis for both low linear energy transfer (LET) treatment with photons or protons and high-LET treatment with heavy ions. A detailed analysis of experimental data from the literature with respect to the dose dependence of the oxygen effect is performed, revealing controversial opinions whether the OER increases, decreases or stays constant with dose. The behavior of the OER with dose per fraction depends primarily on the ratios of the LQ parameters alpha and beta under hypoxic and aerobic conditions, which themselves depend on LET, pO2 and the cell or tissue type. According to our calculations, the OER variations with dose in vivo for low-LET treatments are moderate, with changes in the OER up to 11% for dose painting (1 or 3 Gy per fraction compared to 2 Gy) and up to 22% in hyper-/hypofractionation (0.5 or 20 Gy per fraction compared to 2 Gy) for oxygen tensions between 0.2 and 20 mmHg typically measured clinically in hypoxic tumors. For extremely hypoxic cells (0.01 mmHg), the dose dependence of the OER becomes more pronounced (up to 36

  14. Semi-empirical model for the generation of dose distributions produced by a scanning electron beam

    International Nuclear Information System (INIS)

    Nath, R.; Gignac, C.E.; Agostinelli, A.G.; Rothberg, S.; Schulz, R.J.

    1980-01-01

    There are linear accelerators (Sagittaire and Saturne accelerators produced by Compagnie Generale de Radiologie (CGR/MeV) Corporation) which produce broad, flat electron fields by magnetically scanning the relatively narrow electron beam as it emerges from the accelerator vacuum system. A semi-empirical model, which mimics the scanning action of this type of accelerator, was developed for the generation of dose distributions in homogeneous media. The model employs the dose distributions of the scanning electron beams. These were measured with photographic film in a polystyrene phantom by turning off the magnetic scanning system. The mean deviation calculated from measured dose distributions is about 0.2%; a few points have deviations as large as 2 to 4% inside of the 50% isodose curve, but less than 8% outside of the 50% isodose curve. The model has been used to generate the electron beam library required by a modified version of a commercially-available computerized treatment-planning system. (The RAD-8 treatment planning system was purchased from the Digital Equipment Corporation. It is currently available from Electronic Music Industries

  15. Monte Carlo assessment of the dose rates produced by spent fuel from CANDU reactors

    International Nuclear Information System (INIS)

    Pantazi, Doina; Mateescu, Silvia; Stanciu, Marcela

    2003-01-01

    One of the technical measures considered for biological protection is radiation shielding. The implementation process of a spent fuel intermediate storage system at Cernavoda NPP includes an evolution in computation methods related to shielding evaluation: from using simpler computer codes, like MicroShield and QAD, to systems of codes, like SCALE (which contains few independent modules) and the multipurpose and multi-particles transport code MCNP, based on Monte Carlo method. The Monte Carlo assessment of the dose rates produced by CANDU type spent fuel, during its handling for the intermediate storage, is the main objective of this paper. The work had two main features: -establishing of geometrical models according to description mode used in code MCNP, capable to account for the specific characteristics of CANDU nuclear fuel; - confirming the correctness of proposed models, by comparing MCNP results and the related results obtained with other computer codes for shielding evaluation and dose rates calculations. (authors)

  16. Tacrolimus concentration/dose ratio as a therapeutic drug monitoring strategy: The influence of gender and comedication

    Directory of Open Access Journals (Sweden)

    Rančić Nemanja

    2015-01-01

    Full Text Available Background/Aim. A combination of tacrolimus and other drugs such as corticosteroids has been commonly used immunosuppresive regimens. On the other hand, there is a growing body of evidence that male and female may differ in their response to the equal drug treatment. The aim of the study was to estimated the use of tacrolimus concentration/dose (C/D ratio for the assessment of the influence of gender differences and comedication on tacrolimus exposure in renal transplant recipients. Methods. This prospective case series study included 54 patients, in which the unit of monitoring was outpatient examination (1,872 of the renal transplant patients. The patients were monitored in the period 2010-2014, starting one month after the transplantation. Tacrolimus trough concentrations (TTC were measured by chemiluminescence microparticles immunoassay. Results. TTC and the tacrolimus C/D ratio were significantly lower in the females comparing with the males. Contrary to the males, in the females a significant increase of the tacrolimus daily dose (TDD per body weight and TTC, along with the corticosteroid dose increase, was not accompanied by any significant changes in the tacrolimus C/D ratio; in different corticosteroid doses faster elimination of tacrolimus was found with the exception of the doses > 0.25 mg/kg. In the patients treated with proton pump inhibitors, mainly with pantoprazole TDD per body weight and TTC were significantly higher, while the tacrolimus C/D ratio was significantly lower compared to the patients without this treatment. In the patients treated with calcium channel blockers, TDD per body weight was significantly lower (particularly with amlodipine while the tacrolimus C/D ratio was higher compared to the patients who were not treated by them. Conclusion. A lower tacrolimus exposure was detected in females in comparison to males. When gender differences were considered in the context of different corticosteroid doses, faster

  17. Studying the effect of compression ratio on an engine fueled with waste oil produced biodiesel/diesel fuel

    Directory of Open Access Journals (Sweden)

    Mohammed EL_Kassaby

    2013-03-01

    Full Text Available Wasted cooking oil from restaurants was used to produce neat (pure biodiesel through transesterification, and then used to prepare biodiesel/diesel blends. The effect of blending ratio and compression ratio on a diesel engine performance has been investigated. Emission and combustion characteristics was studded when the engine operated using the different blends (B10, B20, B30, and B50 and normal diesel fuel (B0 as well as when varying the compression ratio from 14 to 16 to 18. The result shows that the engine torque for all blends increases as the compression ratio increases. The bsfc for all blends decreases as the compression ratio increases and at all compression ratios bsfc remains higher for the higher blends as the biodiesel percent increase. The change of compression ratio from 14 to 18 resulted in, 18.39%, 27.48%, 18.5%, and 19.82% increase in brake thermal efficiency in case of B10, B20, B30, and B50 respectively. On an average, the CO2 emission increased by 14.28%, the HC emission reduced by 52%, CO emission reduced by 37.5% and NOx emission increased by 36.84% when compression ratio was increased from 14 to 18. In spite of the slightly higher viscosity and lower volatility of biodiesel, the ignition delay seems to be lower for biodiesel than for diesel. On average, the delay period decreased by 13.95% when compression ratio was increased from 14 to 18. From this study, increasing the compression ratio had more benefits with biodiesel than that with pure diesel.

  18. Dose coefficients for radionuclides produced in high energy proton accelerator facilities. Coefficients for radionuclides not listed in ICRP publications

    CERN Document Server

    Kawai, K; Noguchi, H

    2002-01-01

    Effective dose coefficients, the committed effective dose per unit intake, by inhalation and ingestion have been calculated for 304 nuclides, including (1) 230 nuclides with half-lives >= 10 min and their daughters that are not listed in ICRP Publications and (2) 74 nuclides with half-lives < 10 min that are produced in a spallation target. Effective dose coefficients for inhalation of soluble or reactive gases have been calculated for 21 nuclides, and effective dose rates for inert gases have been calculated for 9 nuclides. Dose calculation was carried out using a general-purpose nuclear decay database DECDC developed at JAERI and a decay data library newly compiled from the ENSDF for the nuclides abundantly produced in a spallation target. The dose coefficients were calculated with the computer code DOCAP based on the respiratory tract model and biokinetic model of ICRP. The effective dose rates were calculated by considering both external irradiation from the surrounding cloud and irradiation of the lun...

  19. Cs-137 in milk produced in lituania dose in infants by infants

    International Nuclear Information System (INIS)

    Jerez Vegueria, S.F.; Frometa Suarez, I.

    1997-01-01

    The Chernovil accident caused a wide dispersion of radionuclides over extended in Europe and a part of the Spetentrional hemisphere giving to radionuclides enters in teh food cahins. Our country recived a shipment of evaporated, milkproduced in Lituania to fed infants la Habana City. Taking into account the origin and the final use of the mentioned product, a study was necessary in order to determine the content of Cs-137, one of the radionuclides released in teh accident withmost persistance in the environment because its long half life /30 yeras), and the doses produced by ingestion. The analysi were performed by a gamma spectrometry system using a 7,62cm.x7,62cm. NaI(TL) detector. The content of radioactivity measured in milk was 9,48+2,37 Bq/I and the effective committment dose per caput, due the consumption in four months, was appraised to be 9,40 uSv for a collective dose of 0,22 man-Sv

  20. Graphical user interface for yield and dose estimations for cyclotron-produced technetium

    Science.gov (United States)

    Hou, X.; Vuckovic, M.; Buckley, K.; Bénard, F.; Schaffer, P.; Ruth, T.; Celler, A.

    2014-07-01

    The cyclotron-based 100Mo(p,2n)99mTc reaction has been proposed as an alternative method for solving the shortage of 99mTc. With this production method, however, even if highly enriched molybdenum is used, various radioactive and stable isotopes will be produced simultaneously with 99mTc. In order to optimize reaction parameters and estimate potential patient doses from radiotracers labeled with cyclotron produced 99mTc, the yields for all reaction products must be estimated. Such calculations, however, are extremely complex and time consuming. Therefore, the objective of this study was to design a graphical user interface (GUI) that would automate these calculations, facilitate analysis of the experimental data, and predict dosimetry. The resulting GUI, named Cyclotron production Yields and Dosimetry (CYD), is based on Matlab®. It has three parts providing (a) reaction yield calculations, (b) predictions of gamma emissions and (c) dosimetry estimations. The paper presents the outline of the GUI, lists the parameters that must be provided by the user, discusses the details of calculations and provides examples of the results. Our initial experience shows that the proposed GUI allows the user to very efficiently calculate the yields of reaction products and analyze gamma spectroscopy data. However, it is expected that the main advantage of this GUI will be at the later clinical stage when entering reaction parameters will allow the user to predict production yields and estimate radiation doses to patients for each particular cyclotron run.

  1. Empirical methods to calculate an erythropoiesis-stimulating agent dose conversion ratio in nondialyzed patients with chronic kidney disease.

    Science.gov (United States)

    Horowitz, Jeffrey; Agarwal, Anil; Huang, Fannie; Gitlin, Matthew; Gandra, Shravanthi R; Cangialose, Charles B

    2009-01-01

    Epoetin alfa and darbepoetin alfa are erythropoiesis-stimulating agents (ESAs) indicated for the treatment of anemia in chronic renal failure, including patients on dialysis and patients not on dialysis. Clinical experience demonstrates that the dose conversion ratio (DCR) between epoetin alfa and darbepoetin alfa is nonproportional across the dosing spectrum. However, previous calculations of the dose relationship between epoetin alfa and darbepoetin alfa, described in previous work as the "dose ratio" (DR), (a) used cross-sectional designs (i.e., compared mean doses for patient groups using each ESA) and were therefore vulnerable to confounding or (b) did not adjust for the nonproportional dose relationship. DRs reported in the literature range from 217:1 to 287:1 epoetin alfa (Units [U]):darbepoetin alfa (micrograms [micrograms]). Payers may need a single DCR that accounts for the nonproportional dose relationship to evaluate the economic implications of converting a nondialyzed patient population with chronic kidney disease (CKD) from epoetin alfa to darbepoetin alfa. To estimate a single mean maintenance DCR between epoetin alfa and darbepoetin alfa in subjects with CKD not receiving dialysis, using methods that take into account the nonproportional dose relationship between the 2 ESAs. This was a post-hoc analysis of a subset of patients enrolled in an unpublished, open-label, single arm phase 3 clinical trial (ClinTrial. gov identifier NCT00093977) that was completed in 2006. Although the clinical trial enrolled both dialyzed and nondialyzed patients, the present study used a patient subset comprising nondialyzed patients with CKD previously receiving weekly or every-other-week (Q2W) epoetin alfa who were switched to Q2W darbepoetin alfa to maintain hemoglobin (Hb) levels between 11.0 and 13.0 grams per deciliter. A population mean DCR was estimated using 2 methods: (a) a regression-based method in which the log-transformed (natural logarithm) mean weekly

  2. [Randomized Comparison of Two Approaches to Initial Warfarin Dosing: Time in Therapeutic Range of International Normalized Ratio During Hospitalization].

    Science.gov (United States)

    Gordeev, I G; Averkov, O V; Mishchenko, L N; Levchuk, N N; Vechorko, V I

    2017-09-01

    To perform a randomized, open-label comparison of average time in therapeutic range (TTR) of international normalized ratio (INR) using two approaches to initial warfarin dosing during hospitalization: the standard method and the one using individual patient characteristics (clinical algorithm - the studied approach). We randomly assigned 60 patients with different indications for vitamin K antagonist therapy to the studied approach (n=31, intervention group) or to the standard method (n=29, control group). А target INR range for all patients was 2.0 to 3.0. The average TTR and portions of INR values within target range during the whole time of drug dosing turned out to be small. TTR was 22.4% with standard method and 21.4% with clinical algorithm, which was well below desired 60%. The opportunities for achieving target INR in inpatient settings, regardless of warfarin dosing regimen, are limited.

  3. Ratios between effective doses for tomographic and mathematician models due to internal exposure of photons

    International Nuclear Information System (INIS)

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

    2005-01-01

    The development of new and sophisticated Monte Carlo codes and tomographic human phantoms or voxels motivated the International Commission on Radiological Protection (ICRP) to revise the traditional models of exposure, which have been used to calculate effective dose coefficients for organs and tissues based on mathematician phantoms known as MIRD5. This paper shows the results of calculations using tomographic phantoms MAX (Male Adult voXel) and FAX (Female Adult voXel), recently developed by the authors as well as with the phantoms ADAM and EVA, of specific genres, type MIRD5, coupled to the EGS4 Monte Carlo and MCNP4C codes, for internal exposure with photons of energies between 10 keV and 4 MeV to several organs sources. Effective Doses for both models, tomographic and mathematician, will be compared separately as a function of the Monte Carlo code replacement, of compositions of human tissues and the anatomy reproduced through tomographs. The results indicate that for photon internal exposure, the use of models of exposure based in voxel, increases the values of effective doses up to 70% for some organs sources considered in this study, when compared with the corresponding results obtained with phantoms of MIRD-5 type

  4. Experimental ratio between the 'real' dose per organ and the calculated dose determined by means of the Embalse nuclear power plant's personal dosimeter

    International Nuclear Information System (INIS)

    Thomasz, E.; Salas, C.A.

    1987-01-01

    The specific purpose of the study was to determine the experimental ratio between the reading of dosimeters used by the personnel of the Embalse nuclear power plant and the 'real' dose absorbed by the worker in different organs. An anthropomorphic phantom ALDERSON internal and externally loaded with approximately 150 TLD crystals was used. This phantom was placed in five enclosures that were usually occupied by workers of the Embalse nuclear power plant. In this way, the average dose per organ and the effective equivalent dosis in each enclosure could be calculated and compared with the personal dosimeters placed over the thorax and the conversion factor rem/rem for each enclosure was determined. The average factor resulting from the five considered enclosures was 0.73 rem/rem. This means that the personal dosimeters over value the real dosis absorbed by the personnel of the Embalse nuclear power plant in approximately 37%. (Author)

  5. Genetically significant dose and sex ratio of the offsprings of patient treated with 131I for hyperthyroidism

    International Nuclear Information System (INIS)

    Takeshita, Akihisa

    1975-01-01

    The gonadal doses following the 131 I treatment of 6 male and 14 female patients with hyperthyroidism were calculated by the method of MIRD, measuring daily radioactivity in the thyroid gland and circulating blood. The testicular dose was 0.52 +- 0.256 rads and the ovarian dose was 0.632 +- 0.488 rads per mCi. In 1965, the genetically significant dose from 131 I treatment of 925 patients with hyperthyroidism was estimated to be 0.0136 mrads/person/year. The genetically significant dose would amount to 0.0613 mrads/person/year, assuming that the total amount of 131 I supplied for treatment in 1965 was administered to treat the hyperthyroid patients with an age-and sex distribution similar to that of the above mentioned group of patients. Sex ratios of the offspring of male and female patients treated with 131 I from 1953 to 1966 were compared with those of offspring born to male and female patients before the treatment. The proportion of males was higher among the offspring of male patients after 131 I treatment than among the offspring of the controls, but the difference was not statistically significant. The sex ratio of the offspring of female patients was not different from that of controls. The mean age of the parents at the times of their children's birth after 131 I treatment was 2.6 - 6.0 year older in male patients and 2.8 - 2.9 year older in female patients than that of controls. (J.P.N.)

  6. Increased interleukin-1β levels following low dose MDMA induces tolerance against the 5-HT neurotoxicity produced by challenge MDMA

    Directory of Open Access Journals (Sweden)

    Mayado Andrea

    2011-11-01

    Full Text Available Abstract Background Preconditioning is a phenomenon by which tolerance develops to injury by previous exposure to a stressor of mild severity. Previous studies have shown that single or repeated low dose MDMA can attenuate 5-HT transporter loss produced by a subsequent neurotoxic dose of the drug. We have explored the mechanism of delayed preconditioning by low dose MDMA. Methods Male Dark Agouti rats were given low dose MDMA (3 mg/kg, i.p. 96 h before receiving neurotoxic MDMA (12.5 mg/kg, i.p.. IL-1β and IL1ra levels and 5-HT transporter density in frontal cortex were quantified at 1 h, 3 h or 7 days. IL-1β, IL-1ra and IL-1RI were determined between 3 h and 96 h after low dose MDMA. sIL-1RI combined with low dose MDMA or IL-1β were given 96 h before neurotoxic MDMA and toxicity assessed 7 days later. Results Pretreatment with low dose MDMA attenuated both the 5-HT transporter loss and elevated IL-1β levels induced by neurotoxic MDMA while producing an increase in IL-1ra levels. Low dose MDMA produced an increase in IL-1β at 3 h and in IL-1ra at 96 h. sIL-1RI expression was also increased after low dose MDMA. Coadministration of sIL-1RI (3 μg, i.c.v. prevented the protection against neurotoxic MDMA provided by low dose MDMA. Furthermore, IL-1β (2.5 pg, intracortical given 96 h before neurotoxic MDMA protected against the 5-HT neurotoxicity produced by the drug, thus mimicking preconditioning. Conclusions These results suggest that IL-1β plays an important role in the development of delayed preconditioning by low dose MDMA.

  7. Increased interleukin-1β levels following low dose MDMA induces tolerance against the 5-HT neurotoxicity produced by challenge MDMA

    Science.gov (United States)

    2011-01-01

    Background Preconditioning is a phenomenon by which tolerance develops to injury by previous exposure to a stressor of mild severity. Previous studies have shown that single or repeated low dose MDMA can attenuate 5-HT transporter loss produced by a subsequent neurotoxic dose of the drug. We have explored the mechanism of delayed preconditioning by low dose MDMA. Methods Male Dark Agouti rats were given low dose MDMA (3 mg/kg, i.p.) 96 h before receiving neurotoxic MDMA (12.5 mg/kg, i.p.). IL-1β and IL1ra levels and 5-HT transporter density in frontal cortex were quantified at 1 h, 3 h or 7 days. IL-1β, IL-1ra and IL-1RI were determined between 3 h and 96 h after low dose MDMA. sIL-1RI combined with low dose MDMA or IL-1β were given 96 h before neurotoxic MDMA and toxicity assessed 7 days later. Results Pretreatment with low dose MDMA attenuated both the 5-HT transporter loss and elevated IL-1β levels induced by neurotoxic MDMA while producing an increase in IL-1ra levels. Low dose MDMA produced an increase in IL-1β at 3 h and in IL-1ra at 96 h. sIL-1RI expression was also increased after low dose MDMA. Coadministration of sIL-1RI (3 μg, i.c.v.) prevented the protection against neurotoxic MDMA provided by low dose MDMA. Furthermore, IL-1β (2.5 pg, intracortical) given 96 h before neurotoxic MDMA protected against the 5-HT neurotoxicity produced by the drug, thus mimicking preconditioning. Conclusions These results suggest that IL-1β plays an important role in the development of delayed preconditioning by low dose MDMA. PMID:22114930

  8. Stability Study of Iriba Brucellosis Full-dose and Reduced-dose Vaccine Produced by Razi Institute in Iran

    Directory of Open Access Journals (Sweden)

    Hasannia, E.

    2015-04-01

    Full Text Available Stability study of biological products plays an important role for determination of product changes in maintenance period and ensuring of safety and efficacy of vaccines. In this research, accelerated and long-term stability study performed for six batches of full and reduced-dose cattle Iriba strain brucellosis vaccine that manufactured by Razi vaccine and serum research institute as a new vaccine. After sampling, the vaccines were tested for accelerated stability, after four days storage at 22 0C and tested intervals in three months until 24 months for long-term stability after storage at 2-8 0C. The result indicated all batches of vaccines in accelerated stability met the specification recommended by OIE 2012 and the mean loss of activity for full-dose was 16.68, 18.87 and 17.79 % and for reduced-dose was 38.85, 36.06 and 34.98 %. In long term stability, the quality control tests including colony forming unit, purity, dissociation and physicochemical tests in all samples until 24 months, met the specification recommended by OIE 2012. The full-dose vaccines showed a mean loss of activity of 30.73, 25.53 and 32.45 % and the reduced-dose vaccines showed 63.51, 58.60 and 60.83 %. The mean increasing of moisture content was, 187.85, 214.13 and 160.77 % for full-dose and 142.35, 110.23 and 164.47 % for reduced-dose. So, the results of this research indicated in spite of moisture content increasing in second year, the brucellosis vaccines with this strain are stable at least 24months if the cold chain considered properly but the best expiry date for the vaccine is one year.

  9. Fixed ratio dosing of pramlintide with regular insulin before a standard meal in patients with type 1 diabetes.

    Science.gov (United States)

    Riddle, M C; Yuen, K C J; de Bruin, T W; Herrmann, K; Xu, J; Öhman, P; Kolterman, O G

    2015-09-01

    Amylin is co-secreted with insulin and is therefore lacking in patients with type 1 diabetes. Replacement with fixed ratio co-administration of insulin and the amylin analogue pramlintide may be superior to separate dosing. This concept was evaluated in a ratio-finding study. Patients with type 1 diabetes were enrolled in a randomized, single-masked, standard breakfast crossover study using regular human insulin injected simultaneously with pramlintide 6, 9 or 12 mcg/unit insulin or placebo. Insulin dosage was reduced by 30% from patients' usual estimates. Plasma glucose, glucagon and pramlintide and adverse events were assessed. All ratios reduced 0-3-h glucose and glucagon increments by >50%. No hypoglycaemia occurred. Adverse events were infrequent and generally mild. All pramlintide/insulin ratios markedly and safely reduced glycaemic excursions and suppressed glucagon secretion in the immediate postprandial state. Further study using one of these ratios to explore the efficacy and safety of longer-term meal-time and basal hormone replacement is warranted. © 2015 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

  10. Monte Carlo simulation on hard X-ray dose produced in interaction between high intensity laser and solid target

    International Nuclear Information System (INIS)

    Yang Bo; Qiu Rui; Li Junli; Zhang Hui

    2014-01-01

    The X-ray dose produced in the interaction between high intensity laser and solid target was studied by simulation using Monte Carlo code. Compared with experimental results, the calculation model was verified. The calculation model was used to study the effect on X-ray dose with different electron temperatures, target materials (including Au, Cu and PE) and thicknesses. The results indicate that the X-ray dose is mainly determined by the electron temperature, and will be affected by the target parameters. X-ray dose of Au is about 1.2 times that of Cu, and is about 5 times that of PE (polyethylene). In addition, compared with other target thickness, when target thickness is the mean range of electron in the target, X-ray dose is relatively large. These results will provide references on evaluating the ionizing radiation dose for laser devices. (authors)

  11. Determination of the carbon content of domestic farm produces to estimate offsite C-14 ingestion dose

    International Nuclear Information System (INIS)

    Jung, Y. G.; Kim, M. J.; Lee, G. B.

    2003-01-01

    The carbon content of grains, leafy and root vegetables, and fruits which the Koreans usually eat were calculated to use in the estimation of offsite C-14 ingestion dose. With the data of food intake per day in the Report on 1998 national health and nutrition survey- dietary intake survey, 5 age-group integrate d intake of the 4 farm produce groups were extracted for food items and the amount. Intake percentage in each food group were taken as food weighing factor for the foods. Carbon content was calculated using protein, fat, and carbohydrate content of the foods, and multiplied by the corresponding food weighing factor to derive the content of the food groups. The calculated carbon content of grains, leafy and root vegetables, and fruits were 39.%, 4.2%, 8.0%, and 5.9% respectively. Grains and fruits were not much different from ODCM for carbon content, but vegetables were higher by 0.7%∼4.5%

  12. Commercial production and distribution of fresh fruits and vegetables: A scoping study on the importance of produce pathways to dose. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, T.L.; Anderson, D.M.; Farris, W.T.; Ikenberry, T.A.; Napier, B.A.; Wilfert, G.L.

    1992-09-01

    This letter report summarizes a scoping study that examined the potential importance of fresh fruit and vegetable pathways to dose. A simple production index was constructed with data collected from the Washington State Department of Agriculture (WSDA), the United States Bureau of the Census, and the United States Department of Agriculture (USDA). Hanford Environmental Dose Reconstruction (HEDR) Project staff from Battelle, Pacific Northwest Laboratories, in cooperation with members of the Technical Steering Panel (TSP), selected lettuce and spinach as the produce pathways most likely to impact dose. County agricultural reports published in 1956 provided historical descriptions of the predominant distribution patterns of fresh lettuce and spinach from production regions to local population centers. Pathway rankings and screening dose estimates were calculated for specific populations living in selected locations within the HEDR study area.

  13. Effect of B/Ti mass ratio on grain refining of low-titanium aluminum produced by electrolysis

    International Nuclear Information System (INIS)

    Wang Mingxing; Wang Sanjun; Liu Zhiyong; Liu Zhongxia; Song Tianfu; Zuo Xiurong

    2006-01-01

    The effect of B/Ti mass ratio on grain refining of the low-titanium aluminum produced by electrolysis was investigated by adding AlB master alloy to the melt of the low-titanium aluminum. The results show that the addition of titanium by electrolysis is an effective way of grain refining of aluminum, and addition of boron to the melt of the low-titanium aluminum can further increase the grain refining efficiency. And the best grain refining efficiency is obtained when the B/Ti mass ratio is 1:10. However, when the B/Ti mass ratio is 1:2.22 (the stoichiometric value for TiB 2 ), the grain refining efficiency vanishes almost completely. It means that all of the solute titanium atoms in the melt of the low-titanium aluminum react with boron atoms that come from AlB master alloy to form TiB 2 particles, and TiB 2 particles have not grain refining ability. The grain refining efficiency seems to increase with addition of more boron to the melt after the B/Ti mass ratio exceeds 1:2.22. But the grain refining efficiency is very poor, and similar to that of pure Al refined by AlB master alloy. It further shows that TiB 2 particles do not participate in grain refining, and that the excess boron atoms in the melt also cannot turn TiB 2 particles into the effective nuclei for aluminum as the solute titanium atoms do

  14. [Oxygen enhancement ratio (OER) and therapeutic gain factor (GF) for low-dose irradiation with californium-252].

    Science.gov (United States)

    Wambersie, A; Van Dam, J; Octave-Prignot, M; Dutreix, A

    1982-01-01

    The potential benefit of the introduction of californium-252 in interstitial and intracavitary therapy is related to the greater efficiency of its neutron emission against anoxic cancer cells. In that respect, the oxygen enhancement ratio (OER) of the 252Cf emission has been determined for a continuous low dose rate irradiation. The biological system is growth inhibition in Vicia faba bean roots. A new Vicia faba "BelB" strain has been used, which better tolerates long periods (up to about 10 hours) of anoxia. In a first series of experiments, for a 252Cf (Dn + gamma) dose rate of 0.11 Gy . h-1, an OER of 1.4 +/- 0.1 was observed (the gamma contribution of D gamma to the total absorbed dose Dn + gamma was 0.35 at the position of the root tips). In a second series of experiments, in somewhat different geometrical conditions with a 252Cf (Dn + gamma) dose rate of 0.13 Gy . h-1, an OER of 1.5 +/- 0.1 was observed (D gamma/Dn + gamma = 0.42). The OER values observed for similar irradiation times, with iridium-192 gamma-rays, were 2.3 +/- 0.2 and 2.6 +/- 0.1 respectively, which leads to therapeutic gain factors (GF) of 1.6 and 1.7 respectively. These GF values are slightly lower than those previously obtained (GF = 1.8) on the same system, with d(50)-Be, p(75)-Be and 15 MeV neutron beams.

  15. Evaluating irradiation dose for sterility induction and quality control of mass-produced fruit fly Bactrocera tryoni (Diptera: Tephritidae).

    Science.gov (United States)

    Dominiak, B C; Sundaralingam, S; Jiang, L; Fanson, B G; Collins, S R; Banos, C; Davies, J B; Taylor, P W

    2014-06-01

    The sterile insect technique has been routinely used to eradicate fruit fly Bactrocera tryoni (Froggatt) incursions. This study considers whether fly quality in a mass-rearing facility can be improved by reducing irradiation doses, without sacrificing reproductive sterility. Pupae were exposed to one of five target irradiation dose ranges: 0, 40-45, 50-55, 60-65, and 70-75 Gy. Pupae were then assessed using routine quality control measures: flight ability, sex ratio, longevity under nutritional stress, emergence, and reproductive sterility. Irradiation did not have a significant effect on flight ability or sex ratio tests. Longevity under nutritional stress was significantly increased at 70-75 Gy, but no other doses differed from 0 Gy. Emergence was slightly reduced in the 50-55, 60-65, and 70-75 Gy treatments, but 40-45 Gy treatments did not differ from 0 Gy, though confounding temporal factors complicate interpretation. Reproductive sterility remained acceptable (> 99.5%) for all doses--40-45 Gy (99.78%), 50-55 Gy (100%), 60-65 Gy (100%), and 70-75 Gy (99.99%). We recommend that B. tryoni used in sterile insect technique releases be irradiated at a target dose of 50-55 Gy, providing improved quality and undiminished sterility in comparison with the current 70-75 Gy standard while also providing a substantial buffer against risk of under dosing.

  16. Data storage on Russian pesticide producers exposed to dioxin. Sex ratios of third generation of Russian cohort

    Energy Technology Data Exchange (ETDEWEB)

    Amirova, Z.; Kruglov, E. [Environmental Research and Protection Center, Ufa (Russian Federation); Dardynskaia, I. [Univ. of Illinois, School of Public Health, Chicago (United States)

    2004-09-15

    A cohort of Russian workers who produced 2,4,5-T and 2,4,5-TrCP at a chemical factory in Ufa was brought to light in the papers of A. Schecter, J. Ryan and O. Papke. Dioxin exposure was experimentally confirmed by PCDD/Fs determination in blood samples first for a small group of workers and their children. This study permitted to connect the information of medical institutions about chloracne from which a group of young 2,4,5-T workers suffered in 1965-67 with exposure to dioxin. This report presents the results of the detailed study of the third generation of the Russian cohort (247 workers, 314 children and 260 grandchildren). We also present the data on the sex ratio of the second generation for the initial group enlarged by 25% as compared with the group of workers analyzed by J. Ryan et al. (198 workers and 227 children). Besides, as skewed sex ratio had earlier been stated only for paternal descendants, genealogical branches of the cohort representatives were studied.

  17. Properties of laser-produced GaAs plasmas measured from highly resolved X-ray line shapes and ratios

    Science.gov (United States)

    Seely, J. F.; Fein, J.; Manuel, M.; Keiter, P.; Drake, P.; Kuranz, C.; Belancourt, Patrick; Ralchenko, Yu.; Hudson, L.; Feldman, U.

    2018-03-01

    The properties of hot, dense plasmas generated by the irradiation of GaAs targets by the Titan laser at Lawrence Livermore National Laboratory were determined by the analysis of high resolution K shell spectra in the 9 keV to 11 keV range. The laser parameters, such as relatively long pulse duration and large focal spot, were chosen to produce a steady-state plasma with minimal edge gradients, and the time-integrated spectra were compared to non-LTE steady state spectrum simulations using the FLYCHK and NOMAD codes. The bulk plasma streaming velocity was measured from the energy shifts of the Ga He-like transitions and Li-like dielectronic satellites. The electron density and the electron energy distribution, both the thermal and the hot non-thermal components, were determined from the spectral line ratios. After accounting for the spectral line broadening contributions, the plasma turbulent motion was measured from the residual line widths. The ionization balance was determined from the ratios of the He-like through F-like spectral features. The detailed comparison of the experimental Ga spectrum and the spectrum simulated by the FLYCHK code indicates two significant discrepancies, the transition energy of a Li-like dielectronic satellite (designated t) and the calculated intensity of a He-like line (x), that should lead to improvements in the kinetics codes used to simulate the X-ray spectra from highly-charged ions.

  18. Radiation sources providing increased UVA/UVB ratios induce photoprotection dependent on the UVA dose in hairless mice.

    Science.gov (United States)

    Reeve, Vivienne E; Domanski, Diane; Slater, Michael

    2006-01-01

    In studies involving mice in which doses of UVA (320-400 nm) and UVB (290-320 nm) radiation were administered alone or combined sequentially, we observed a protective effect of UVA against UVB-induced erythema/edema and systemic suppression of contact hypersensitivity. The UVA immunoprotection was mediated by the induction of the stress enzyme heme oxygenase-1 (HO-1) in the skin, protection of the cutaneous Th1 cytokines interferon-gamma (IFN-gamma) and IL-12 and inhibition of the UVB-induced expression of the Th2 cytokine IL-10. In this study, we seek evidence for an immunological waveband interaction when UVA and UVB are administered concurrently to hairless mice as occurs during sunlight exposure in humans. A series of spectra providing varying ratios of UVA/UVB were developed, with the UVA ratio increased to approximately 3.5 times the UVA component in solar simulated UV (SSUV). We report that progressively increasing the UVA component of the radiation while maintaining a constant UVB dose resulted in a reduction of both the erythema/edema reaction and the degree of systemic immunosuppression, as measured as contact hypersensitivity. The UVA-enhanced immunoprotection was abrogated in mice treated with a specific HO enzyme inhibitor. UVA-enhanced radiation also upregulated the expression of cutaneous IFN-gamma and IL-12 and inhibited expression of both IL-6 and IL-10, compared with the activity of SSUV. The results were consistent with the previously characterized mechanisms of photoprotection by the UVA waveband alone and suggest that the UVA component of solar UV may have beneficial properties for humans.

  19. Feasibility of using a dose-area product ratio as beam quality specifier for photon beams with small field sizes.

    Science.gov (United States)

    Pimpinella, Maria; Caporali, Claudio; Guerra, Antonio Stefano; Silvi, Luca; De Coste, Vanessa; Petrucci, Assunta; Delaunay, Frank; Dufreneix, Stéphane; Gouriou, Jean; Ostrowsky, Aimé; Rapp, Benjamin; Bordy, Jean-Marc; Daures, Josiane; Le Roy, Maïwenn; Sommier, Line; Vermesse, Didier

    2018-01-01

    To investigate the feasibility of using the ratio of dose-area product at 20 cm and 10 cm water depths (DAPR 20,10 ) as a beam quality specifier for radiotherapy photon beams with field diameter below 2 cm. Dose-area product was determined as the integral of absorbed dose to water (D w ) over a surface larger than the beam size. 6 MV and 10 MV photon beams with field diameters from 0.75 cm to 2 cm were considered. Monte Carlo (MC) simulations were performed to calculate energy-dependent dosimetric parameters and to study the DAPR 20,10 properties. Aspects relevant to DAPR 20,10 measurement were explored using large-area plane-parallel ionization chambers with different diameters. DAPR 20,10 was nearly independent of field size in line with the small differences among the corresponding mean beam energies. Both MC and experimental results showed a dependence of DAPR 20,10 on the measurement setup and the surface over which D w is integrated. For a given setup, DAPR 20,10 values obtained using ionization chambers with different air-cavity diameters agreed with one another within 0.4%, after the application of MC correction factors accounting for effects due to the chamber size. DAPR 20,10 differences among the small field sizes were within 1% and sensitivity to the beam energy resulted similar to that of established beam quality specifiers based on the point measurement of D w . For a specific measurement setup and integration area, DAPR 20,10 proved suitable to specify the beam quality of small photon beams for the selection of energy-dependent dosimetric parameters. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  20. Commercial production and distribution of fresh fruits and vegetables: A scoping study on the importance of produce pathways to dose

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, T.L.; Anderson, D.M.; Farris, W.T.; Ikenberry, T.A.; Napier, B.A.; Wilfert, G.L.

    1992-09-01

    This letter report summarizes a scoping study that examined the potential importance of fresh fruit and vegetable pathways to dose. A simple production index was constructed with data collected from the Washington State Department of Agriculture (WSDA), the United States Bureau of the Census, and the United States Department of Agriculture (USDA). Hanford Environmental Dose Reconstruction (HEDR) Project staff from Battelle, Pacific Northwest Laboratories, in cooperation with members of the Technical Steering Panel (TSP), selected lettuce and spinach as the produce pathways most likely to impact dose. County agricultural reports published in 1956 provided historical descriptions of the predominant distribution patterns of fresh lettuce and spinach from production regions to local population centers. Pathway rankings and screening dose estimates were calculated for specific populations living in selected locations within the HEDR study area.

  1. Effects of dilution ratio and Fe° dosing on biohydrogen production from dewatered sludge by hydrothermal pretreatment.

    Science.gov (United States)

    Yu, Li; Jiang, Wentian; Yu, Yang; Sun, Chenglin

    2014-01-01

    Biohydrogen fermentation of dewatered sludge (DS) with sewage at ratios from 4:1 to 1:20 was investigated. Hydrothermal pretreatment of the sludge solution was performed to accelerate the organic release from the solid phase. The maximum hydrogen yield of 26.3 ± 0.5 mL H₂/g volatile solid (VS) was obtained at a 1:10 ratio. Although addition of zero valent iron (ZVI) to anaerobic system was not new, the study of dosing it to enhance the biohydrogen yield might be the first attempt. While Fe° plate slightly affected the hydrogen yield, Fe° powder improved the amount of hydrogen by 16% and shortened the lag time by 36%. The state of bacteria in the reactor added with ZVI powder was changed and the key enzyme activity was improved as well. Correspondingly, the mechanism of ZVI in accelerating the biofermentation process was also proposed. Our research provides a solution for the centralized treatment of DS in a city.

  2. K$^{-}$ over K$^{+}$ multiplicity ratio for kaons produced in DIS with a large fraction of the virtual-photon energy

    CERN Document Server

    Akhunzyanov, R.; The COMPASS collaboration; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anfimov, N.V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Bressan, A.; Büchele, M.; Burtsev, V.E.; Capozza, L.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Chumakov, A.G.; Chung, S.-U.; Cicuttin, A.; Crespo, M.L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Dreisbach, Ch.; Dünnweber, W.; Dusaev, R.R.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Faessler, M.; Ferrero, A.; Finger, M.; jr., M.Finger; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J.M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giarra, J.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Gridin, A.; Grosse Perdekamp, M.; Grube, B.; Guskov, A.; Hahne, D.; Hamar, G.; von Harrach, D.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.M.; Kral, Z.; Krämer, M.; Krinner, F.; Kroumchtein, Z.V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Kuznetsov, I.I.; Kveton, A.; Lednev, A.A.; Levchenko, E.A.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Lyubovitskij, V.E.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Mamon, S.A.; Marchand, C.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.V.; Meyer, M.; Meyer, W.; Mikhailov, Yu.V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Moretti, A.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pesaro, G.; Pešek, M.; Pešková, M.; Peshekhonov, D.V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Ryabchikov, D.I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V.D.; Sandacz, A.; Sarkar, S.; Savin, I.A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmieden, H.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sozzi, F.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Tskhay, V.; Uhl, S.; Vasilishin, B.I.; Vauth, A.; Veit, B.M.; Veloso, J.; Vidon, A.; Virius, M.; Wallner, S.; Wilfert, M.; Windmolders, R.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.

    2018-01-01

    The K$^{-}$ over K$^{+}$ multiplicity ratio is measured in deep-inelastic scattering, for the first time for kaons carrying a large fraction $z$ of the virtual-photon energy. The data were obtained by the COMPASS collaboration using a 160 GeV muon beam and an isoscalar $^6$LiD target. The regime of deep-inelastic scattering is ensured by requiring $Q^2>1$ (GeV/$c)^2$ for the photon virtuality and $W>5$ GeV/$c^2$ for the invariant mass of the produced hadronic system. Kaons are identified in the momentum range from 12 GeV/$c$ to 40 GeV/$c$, thereby restricting the range in Bjorken-$x$ to $0.010.75$. For very large values of $z$, $i.e.$ $z>0.8$, the results contradict expectations obtained using the formalism of (next-to-)leading order perturbative quantum chromodynamics. This may imply that cross-section factorisation or/and universality of (kaon) fragmentation functions do not hold. Our studies suggest that within this formalism an additional correction may be required, which takes into account th...

  3. Zero crossing and ratio spectra derivative spectrophotometry for the dissolution tests of amlodipine and perindopril in their fixed dose formulations

    Directory of Open Access Journals (Sweden)

    Maczka Paulina

    2014-06-01

    Full Text Available Dissolution tests of amlodipine and perindopril from their fixed dose formulations were performed in 900 mL of phosphate buffer of pH 5.5 at 37°C using the paddle apparatus. Then, two simple and rapid derivative spectrophotometric methods were used for the quantitative measurements of amlodipine and perindopril. The first method was zero crossing first derivative spectrophotometry in which measuring of amplitudes at 253 nm for amlodipine and 229 nm for perindopril were used. The second method was ratio derivative spectrophotometry in which spectra of amlodipine over the linearity range were divided by one selected standard spectrum of perindopril and then amplitudes at 242 nm were measured. Similarly, spectra of perindopril were divided by one selected standard spectrum of amlodipine and then amplitudes at 298 nm were measured. Both of the methods were validated to meet official requirements and were demonstrated to be selective, precise and accurate. Since there is no official monograph for these drugs in binary formulations, the dissolution tests and quantification procedure presented here can be used as a quality control test for amlodipine and perindopril in respective dosage forms.

  4. Protection by pantothenol and β-carotene against liver damage produced by low-dose γ radiation

    International Nuclear Information System (INIS)

    Slyshenkov, V.S; Omelyanchik, S.N.; Moiseenok, A.G.; Petushok, N.E.; Wojtczak, L.

    1999-01-01

    Rats were exposed to a total dose of 0.75 Gy of γ radiation from a 60 Co source, receiving three doses of 0.25 Gy at weekly intervals. During two days before each irradiation, the animals received daily intragastric doses of 26 mg pantothenol or 15 mg β-carotene per kg body mass. The animals were killed after the third irradiation session, and their blood and livers were analyzed. As found previously, in livers of animals not supplied with either pantothenol or β-carotene and killed one hour after the irradiation, a large accumulation of lipid peroxidation products, as conjugated dienes, ketotrienes and thiobarbituric acid-reactive substances, could be observed. The contents of CoA, pantothenic acid, total phospholipids, total glutathione and GSH/GSSG ratio were considerably decreased, whereas the NAD/NADH ratio was increased. All these effects were alleviated in animals supplied with beta-carotene and were completely abolished in animals supplied with pantothenol. In the present paper, we extended our observations of irradiation effects over a period of up to 7 days after the last irradiation session. We found that most of these changes, with the exception of GSH/GSSG ratio, disappeared spontaneously, whereas supplementation with beta-carotene shortened the time required for the normalization of biochemical parameters. In addition, we found that the activities of glutathione reductase, glutathione peroxidase, catalase and NADP-dependent malate (decarboxylating) dehydrogenase ('malic enzyme') in liver were also significantly decreased one hour after irradiation but returned to the normal level within 7 days. Little or no decrease in these activities, already 1 h after the irradiation, could be seen in animals supplemented with either beta-carotene or pantothenol. It is concluded that pantothenol is an excellent radioprotective agent against low-dose γ radiation. (author)

  5. Assessment of the efficacy of a novel tailored vitamin K dosing regimen in lowering the International Normalised Ratio in over-anticoagulated patients: a randomised clinical trial.

    Science.gov (United States)

    Kampouraki, Emmanouela; Avery, Peter J; Wynne, Hilary; Biss, Tina; Hanley, John; Talks, Kate; Kamali, Farhad

    2017-09-01

    Current guidelines advocate using fixed-doses of oral vitamin K to reverse excessive anticoagulation in warfarinised patients who are either asymptomatic or have minor bleeds. Over-anticoagulated patients present with a wide range of International Normalised Ratio (INR) values and response to fixed doses of vitamin K varies. Consequently a significant proportion of patients remain outside their target INR after vitamin K administration, making them prone to either haemorrhage or thromboembolism. We compared the performance of a novel tailored vitamin K dosing regimen to that of a fixed-dose regimen with the primary measure being the proportion of over-anticoagulated patients returning to their target INR within 24 h. One hundred and eighty-one patients with an index INR > 6·0 (asymptomatic or with minor bleeding) were randomly allocated to receive oral administration of either a tailored dose (based upon index INR and body surface area) or a fixed-dose (1 or 2 mg) of vitamin K. A greater proportion of patients treated with the tailored dose returned to within target INR range compared to the fixed-dose regimen (68·9% vs. 52·8%; P = 0·026), whilst a smaller proportion of patients remained above target INR range (12·2% vs. 34·0%; P K dosing is more accurate than fixed-dose regimen in lowering INR to within target range in excessively anticoagulated patients. © 2017 John Wiley & Sons Ltd.

  6. An extracellular DNA mediated bystander effect produced from low dose irradiated endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Ermakov, Aleksei V., E-mail: avePlato@mail.ru [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Konkova, Marina S.; Kostyuk, Svetlana V.; Smirnova, Tatiana D.; Malinovskaya, Elena M.; Efremova, Liudmila V.; Veiko, Natalya N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation)

    2011-07-01

    The human umbilical vein endothelial cells culture was exposed to X-ray radiation in a low dose of 10 cGy. The fragments of extracellular genomic DNA (ecDNA{sup R}) were isolated from the culture medium after the short-term incubation. A culture medium of unirradiated endothelial cells was then supplemented with ecDNA{sup R}, followed by analysing the cells along the series of parameters (bystander effect). The exposed cells and bystander endotheliocytes showed similar response to low doses: approximation of the 1q12 loci of chromosome 1 and their transposition into the cellular nucleus, change in shape of the endotheliocytic nucleus, activation of the nucleolus organizing regions (NORs), actin polymerization, and an elevated level of DNA double-stranded breaks. Following blockade of TLR9 receptors with oligonucleotide-inhibitor or chloroquine in the bystander cells these effects - except of activation of NORs - on exposure to ecDNA{sup R} disappeared, with no bystander response thus observed. The presence of the radiation-induced apoptosis in the bystander effect being studied suggests a possibility for radiation-modified ecDNA fragments (i.e., stress signaling factors) to be released into the culture medium, whereas inhibition of TLR9 suggests the binding these ligands to the recipient cells. A similar DNA-signaling pathway in the bystander effect we previously described for human lymphocytes. Integrity of data makes it possible to suppose that a similar signaling mechanism which we demonstrated for lymphocytes (humoral system) might also be mediated in a monolayer culture of cells (cellular tissue) after the development of the bystander effect in them and transfer of stress signaling factors (ecDNA{sup R}) through the culture medium.

  7. The ratio of ICRP103 to ICRP60 calculated effective doses from CT: Monte Carlo calculations with the ADELAIDE voxel paediatric model and comparisons with published values.

    Science.gov (United States)

    Caon, Martin

    2013-09-01

    The ADELAIDE voxel model of paediatric anatomy was used with the EGSnrc Monte Carlo code to compare effective dose from computed tomography (CT) calculated with both the ICRP103 and ICRP60 definitions which are different in their tissue weighting factors and in the included tissues. The new tissue weighting factors resulted in a lower effective dose for pelvis CT (than if calculated using ICRP60 tissue weighting factors), by 6.5% but higher effective doses for all other examinations. ICRP103 calculated effective dose for CT abdomen + pelvis was higher by 4.6%, for CT abdomen (by 9.5%), for CT chest + abdomen + pelvis (by 6%), for CT chest + abdomen (by 9.6%), for CT chest (by 10.1%) and for cardiac CT (by 11.5%). These values, along with published values of effective dose from CT that were calculated for both sets of tissue weighting factors were used to determine single values for the ratio ICRP103:ICRP60 calculated effective doses from CT, for seven CT examinations. The following values for ICRP103:ICRP60 are suggested for use to convert ICRP60 calculated effective dose to ICRP103 calculated effective dose for the following CT examinations: Pelvis CT, 0.75; for abdomen CT, abdomen + pelvis CT, chest + abdomen + pelvis CT, 1.00; for chest + abdomen CT, and for chest CT. 1.15; for cardiac CT 1.25.

  8. The ratio of ICRP103 to ICRP60 calculated effective doses from CT: Monte Carlo calculations with the ADELAIDE voxel paediatric model and comparisons with published values

    International Nuclear Information System (INIS)

    Caon, Martin

    2013-01-01

    The ADELAIDE voxel model of paediatric anatomy was used with the EGSnrc Monte Carlo code to compare effective dose from computed tomography (CT) calculated with both the ICRP103 and ICRP60 definitions which are different in their tissue weighting factors and in the included tissues. The new tissue weighting factors resulted in a lower effective dose for pelvis CT (than if calculated using ICRP60 tissue weighting factors), by 6.5 % but higher effective doses for all other examinations. ICRP103 calculated effective dose for CT abdomen + pelvis was higher by 4.6 %, for CT abdomen (by 9.5 %), for CT chest + abdomen + pelvis (by 6 %), for CT chest + abdomen (by 9.6 %), for CT chest (by 10.1 %) and for cardiac CT (by 11.5 %). These values, along with published values of effective dose from CT that were calculated for both sets of tissue weighting factors were used to determine single values for the ratio ICRP103:ICRP60 calculated effective doses from CT, for seven CT examinations. The following values for ICRP103:ICRP60 are suggested for use to convert ICRP60 calculated effective dose to ICRP103 calculated effective dose for the following CT examinations: Pelvis CT, 0.75; for abdomen CT, abdomen + pelvis CT, chest + abdomen + pelvis CT, 1.00; for chest + abdomen CT, and for chest CT. 1.15; for cardiac CT 1.25.

  9. Sterilization of melon flies: mating competitiveness after treatment with tepa or gamma irradiation and ratios of treated to untreated flies producing population suppression

    International Nuclear Information System (INIS)

    Ashraf, M.; Keiser, I.; Harris, E.J.

    1976-01-01

    Male melon flies, Dacus cucurbitae Coquillett, treated with a single dose of the chemosterilant tepa (tris(l-aziridinyl) phosphine oxide), or with gamma irradiation, either single or fractionated doses, did not differ significantly in sexual competitiveness as determined by percentage hatch of eggs. Mating competitiveness of males treated by either method ranged from 53 to 66 percent of that of untreated males. In another study, melon flies (males and females) sterilized with 0.0125 percent tepa, the threshold dose for both sexes, completely suppressed a population when the ratio was 16:16:1:1 (sterile males-sterile females-untreated males-untreated females) as determined by no egg hatch

  10. Influence of perinatal low-dose acetylsalicylic acid therapy on fetal hemodynamics evaluated by determining the acceleration-time/ejection-time ratio in the ductus arteriosus.

    Science.gov (United States)

    Miyazaki, Miwa; Kuwabara, Yoshimitsu; Takeshita, Toshiyuki

    2018-01-01

    Acceleration-time/ejection-time ratio (At/Et ratio) of Doppler waveform is an established hemodynamic parameters that reflect proximal stenosis. Using this parameter, we evaluated whether perinatal low-dose acetylsalicylic acid (ASA) therapy could alter hemodynamics in the ductus arteriosus. Pulse Doppler measurements of the fetal ductus arteriosus were performed longitudinally from 20 to 37 gestational weeks in 106 healthy pregnant women (controls) and 65 pregnant women taking daily low-dose ASA (80 or 100 mg/day) because of a history of recurrent pregnancy loss. The At/Et ratio, pulsatility index (PI), and peak systolic velocity were evaluated and statistically analyzed. The At/Et ratio significantly increased with gestational age in both the ASA group (r = 0.54) and the control group (r = 0.35), while the PI did not. Median peak systolic velocities also increased with gestational age in both the ASA group (r = 0.39) and the control group (r = 0.31). No significant differences in At/Et ratio, PI, or peak systolic velocity were observed between the ASA group and the control group. Administration of low-dose ASA during pregnancy did not appear to alter hemodynamics in the fetal ductus arteriosus. © 2017 Japan Society of Obstetrics and Gynecology.

  11. [Research on search of the carotenoid-producing microorganisms in marine area and the improvement of production ratio].

    Science.gov (United States)

    Sakagami, Yoshikazu; Sumiya, Yasuji; Komemushi, Sadawo

    2010-11-01

    Carotenoids are liposoluble pigments widely distributed in nature. More than 750 carotenoids are isolated from natural sources, but only a few kinds are used industrially. The production of carotenoid by microorganisms is to be expected, but few carotenoids originate from living things on land. And there is little knowledge about carotenoid-producing microorganisms in the oceans. The possibility still exists of discovering new carotenoid-producing microorganisms. Sunlight is very strong in subtropical regions. The surface of the sea and coral reefs in these regions is a severe environment for growth of microorganisms. While such conditions produce reactive oxygen species, the continuing strong irradiation can also lead to damaging and lethal photo-oxidative reactions. Many undiscovered microorganisms may possess protective mechanisms such as anti-oxidative activities for survival in this environment. This study focused on marine microorganisms inhabiting coral reefs in the Okinawa area, especially carotenoid-producing bacteria possessing anti-oxidative activities. Many carotenoid-producing microorganisms were collected from subtropical ocean areas (a total of 334 strains of pigmented microorganisms), and the chemical composition, some culture conditions and genetic characteristics of the carotenoids from these microorganisms were examined. Furthermore, similar research was performed using some creatures from the ocean surrounding Kochi Prefecture.

  12. Sodium and potassium content and their ratio in meatballs in tomato sauce produced with lower amounts of sodium

    Science.gov (United States)

    Lilić, S.; Nikolić, D.; Pejkovski, Z.; Velebit, B.; Lakićević, B.; Korićanac, V.; Vranić, D.

    2017-09-01

    The goal of this study was to examine the possibility of partial replacement of sodium chloride with potassium chloride and ammonium chloride, with the target of achieving less sodium content in meatballs and tomato sauce as well as achieving a better Na:K ratio. The trial consisted of five groups. In the control group of meatballs and sauce, only sodium chloride was added. In group 1, half of the sodium chloride was replaced with potassium chloride related to control group while in group 2 one third of the sodium chloride was replaced with potassium chloride. In group 3, one third of the sodium chloride was replaced with ammonium chloride, and in group 4, sodium chloride was reduced to half the amount in the control group, and 1 g (0.25%) of ammonium chloride was also added. All products were acceptable according to sensory analyses. The largest reductions of sodium content were 44.64%, achieved in meatballs from group 1 and 50.62% in tomato sauce from group 4 in relation to meatballs and tomato sauce from control group. The highest Na:K ratio was calculated in meatballs and tomato sauce from control group, 2.88 and 4.39, respectively. The best Na:K ratio was in meatballs and tomato sauce from group 1, 0.60 and 0.92, respectively, in which half of sodium chloride was replaced with potassium chloride. However, in meatballs and tomato sauce from group 4, with only half the amount of sodium chloride related to control group, the Na:K ratio was worse because in these products, potassium chloride was not added.

  13. The composition of readily available carbon sources produced by fermentation of fish faeces is affected by dietary protein:energy ratios

    DEFF Research Database (Denmark)

    Letelier-Gordo, Carlos Octavio; Larsen, Bodil Katrine; Dalsgaard, Johanne

    2017-01-01

    Fish solid waste (faeces) produced in recirculated aquaculture systems (RAS) might be used for on-farm, single-sludge denitrification if transformed into soluble organic carbon substances. The current study investigated the effect of feeding diets with increasing protein to energy ratios (P:E_15...

  14. Signal-to-noise ratio and dose to the lens of the eye for computed tomography examination of the brain using an automatic tube current modulation system.

    Science.gov (United States)

    Sookpeng, Supawitoo; Butdee, Chitsanupong

    2017-06-01

    The study aimed to evaluate the image quality in terms of signal-to-noise ratio (SNR) and dose to the lens of the eye and the other nearby organs from the CT brain scan using an automatic tube current modulation (ATCM) system with or without CT gantry tilt is needed. An anthropomorphic phantom was scanned with different settings including use of different ATCM, fixed tube current time product (mAs) settings and degree angles of gantry tilt. Gafchromic film XR-QA2 was used to measure absorbed dose of the organs. Relative doses and SNR for the various scan settings were compared with the reference setting of the fixed 330 mAs. Average absorbed dose for the lens of the eyes varied from 8.7 to 21.7 mGy. The use of the ATCM system with the gantry tilt resulted in up to 60% decrease in the dose to the lens of the eye. SNR significantly decreased while tilting the gantry using the fixed mAs techniques, compared to that of the reference setting. However, there were no statistical significant differences for SNRs between the reference setting and all ATCM settings. Compared to the reference setting of the fixed effective mAs, using the ATCM system and appropriate tilting, the gantry resulted in a substantial decrease in the dose to the lens of the eye while preserving signal-to-noise ratio. CT brain examination should be carefully controlled to optimize dose for lens of the eye and image quality of the examination.

  15. Natural gas facility methane emissions: measurements by tracer flux ratio in two US natural gas producing basins

    Directory of Open Access Journals (Sweden)

    Tara I. Yacovitch

    2017-11-01

    Full Text Available Methane (CH4 emission rates from a sample of natural gas facilities across industry sectors were quantified using the dual tracer flux ratio methodology. Measurements were conducted in study areas within the Fayetteville shale play, Arkansas (FV, Sept–Oct 2015, 53 facilities, and the Denver-Julesburg basin, Colorado, (DJ, Nov 2014, 21 facilities. Distributions of methane emission rates at facilities by type are computed and statistically compared with results that cover broader geographic regions in the US (Allen et al., 2013, Mitchell et al., 2015. DJ gathering station emission rates (kg CH4 hr–1 are lower, while FV gathering and production sites are statistically indistinguishable as compared to these multi-basin results. However, FV gathering station throughput-normalized emissions are statistically lower than multi-basin results (0.19% vs. 0.44%. This implies that the FV gathering sector is emitting less per unit of gas throughput than would be expected from the multi-basin distribution alone. The most common emission rate (i.e. mode of the distribution for facilities in this study is 40 kg CH4 hr–1 for FV gathering stations, 1.0 kg CH4 hr–1 for FV production pads, and 11 kg CH4 hr–1 for DJ gathering stations. The importance of study design is discussed, including the benefits of site access and data sharing with industry and of a scientist dedicated to measurement coordination and site choice under evolving wind conditions.

  16. 210Po and 210Pb Activity Concentrations in Cigarettes Produced in Vietnam and Their Estimated Dose Contribution Due to Smoking

    Science.gov (United States)

    Tran, Thuy-Ngan N.; Le, Cong-Hao; Chau, Van-Tao

    Smoking cigarettes contributes significantly to the increase of radiation in human body because 210Po and 210Pb exist relatively high in tobacco leaves. Therefore, these two radioisotopes in eighteen of the most frequently sold cigarette brands produced in Vietnam were examined in this study. 210Po was determined by alpha spectroscopy using a passivated implanted planar silicon (PIPS) detector after a procedure including radiochemical separation and spontaneous deposition of polonium on a copper disc (the deposition efficiency of 210Po on a copper disc was approximately 94%). Sequentially, 210Pb was determined through the ingrowth of 210Po after storing the sample solutions for approximately six months. The activity concentrations of 210Po in cigarettes ranged from 13.8 to 82.6 mBq/cigarette (the mean value was 26.4 mBq/cigarette) and the activity concentrations of 210Pb in cigarettes ranged from 13.9 to 78.8 mBq/cigarette (the mean value was 25.8 mBq/cigarette). The annual committed effective dose for smokers who smoke one pack per day was also estimated to be 295.4 µSv/year (223.0 µSv/year and 72.4 µSv/year from 210Po and 210Pb, respectively). These indicated that smoking increased the risk of developing lung cancer was approximately 60 times greater for smokers than for non-smokers.

  17. A method for producing uniform dose distributions in the junction regions of large hinge angle electrol fields

    International Nuclear Information System (INIS)

    Zavgorodni, S.F.; Beckham, W.A.; Roos, D.E.

    1996-01-01

    The planning problems presented by abutting electron fields are well recognised. Junctioning electron fields with large hinge angle compounds the problems because of the creation of closely situated 'hot' and 'cold' spots. The technique involving a compensated superficial x-ray (SXR) field to treat the junction region between electron fields was developed and used in a particular clinical case (treatment of a squamous cell carcinoma of the forehead/scalp). The SXR beam parameters were chosen and the compensator was designed to make the SXR field complementary to the electron fields. Application of a compensated SXR field eliminated 'cold' spots in the junction region and minimised 'hot' spots to (110%). In the clinical case discusses the 'hot' spots due to the SXR field would not appear because of increased attenuation of the soft x-rays in bone. The technique proposed produces uniform dose distribution up to 3 cm deep and can be considered as an additional tool for dealing with electron fields junctioning problems. (author)

  18. The novel N-type calcium channel blocker, AM336, produces potent dose-dependent antinociception after intrathecal dosing in rats and inhibits substance P release in rat spinal cord slices.

    Science.gov (United States)

    Smith, Maree T; Cabot, Peter J; Ross, Fraser B; Robertson, Alan D; Lewis, Richard J

    2002-03-01

    N-type calcium channels modulate the release of key pro-nociceptive neurotransmitters such as glutamate and substance P (SP) in the central nervous system. Considerable research interest has focused on the therapeutic potential of the peptidic omega-conopeptides, GVIA and MVIIA as novel analgesic agents, due to their potent inhibition of N-type calcium channels. Recently, the novel peptidic N-type calcium channel blocker, AM336, was isolated from the venom of the cone snail, Conus catus. Thus, the aims of this study were to (i) document the antinociceptive effects of AM336 (also known as CVID) relative to MVIIA following intrathecal (i.t.) bolus dosing in rats with adjuvant-induced chronic inflammatory pain of the right hindpaw and to (ii) quantify the inhibitory effects of AM336 relative to MVIIA on K+-evoked SP release from slices of rat spinal cord. Both AM336 and MVIIA inhibited the K+-evoked release of the pro-nociceptive neurotransmitter, SP, from rat spinal cord slices in a concentration-dependent manner (EC50 values=21.1 and 62.9 nM, respectively), consistent with the antinociceptive actions of omega-conopeptides. Following acute i.t. dosing, AM336 evoked dose-dependent antinociception (ED50 approximately 0.110 nmol) but the doses required to produce side-effects were an order of magnitude larger than the doses required to produce antinociception. For i.t. doses of MVIIA0.07 nmol, produced a dose-dependent decrease in antinociception but the incidence and severity of the side-effects continued to increase for all doses of MVIIA investigated, suggesting that dose-titration with MVIIA in the clinical setting, may be difficult.

  19. THE QUALITY CHARACTERISTICS OF MARMALADES PRODUCED AT DIFFERENT SUGAR/PULP RATIOS BY USING ROSE HIPS (Rosa spp PULP OBTAINED WİTHOUT HEATING

    Directory of Open Access Journals (Sweden)

    Feramuz ÖZDEMİR

    1997-02-01

    Full Text Available In this study, Rose hip (Rose spp, which are wildly grown in Erzurum province, were used to produce marmalade. After determining some chemical properties of fruits, pulp was produced using by mechanical crushing without heat application, in order to keep ascorbic acid level. Then marmalades were produced from these pulps based on the ratio of pulp/sugar as 1/0.33, 1/0.50, 1/.075 and 1/1.00, some chemical analysis were done on the samples of marmalade and they were stored under room conditions for five months. At the end of the storage; ascorbic acid, titration acidity, pH and colour were determined as L, a, b. In addition to these manalysis, organoleptic tests were also made on the marmalade samples just after producing marmalade and at the end of the five months. After five months storage; the ascorbic acid was protected in the one sample marmalade consist of 1/50 pulp/sugar comparing with the other samples. The same sample was the best marmalade according to the organoleptic test having 90.1 points out of the 100 points.

  20. A perspective for biowaivers of human bioequivalence studies on the basis of the combination of the ratio of AUC to the dose and the biopharmaceutics classification system.

    Science.gov (United States)

    Sakuma, Shinji; Tachiki, Hidehisa; Uchiyama, Hitoshi; Fukui, Yasunobu; Takeuchi, Naohiro; Kumamoto, Kazuo; Satoh, Tomonori; Yamamoto, Yoshinobu; Ishii, Emi; Sakai, Yoshiyuki; Takeuchi, Susumu; Sugita, Masaru; Yamashita, Shinji

    2011-08-01

    The ratio of AUC to the dose (AUC/dose) was previously found as a parameter that predicts a risk of bioinequivalence of oral drug products. On the basis of the combination of this parameter and the biopharmaceutics classification system (BCS), a perspective for biowaivers of human bioequivalence studies is discussed. Databases of bioequivalence studies using immediate-release solid oral dosage forms were disclosed by 6 Japanese generic pharmaceutical companies, and the number of subjects required for demonstrating bioequivalence between generic and reference products was plotted as a function of AUC/dose for each BCS category. A small variation in the number of subjects was constantly observed in bioequivalence studies using dosage forms containing an identical BCS class 1 or class 3 drug, even though formulations of the generic product differ between companies. The variation was extremely enlarged when the drugs were substituted with BCS class 2 drugs. Rate-determining steps in oral absorption of highly water-soluble BCS class 1 and class 3 drugs are independent of formulations when there is no significant difference in the in vitro dissolution profiles between formulations. The small variation observed for both BCS categories indicates that the number of subjects converges into one value for each drug. Our analysis indicates the appropriateness of biowaiver of bioequivalence studies for immediate-release solid oral dosage forms containing not only BCS class 1 drugs but also class 3 drugs.

  1. The analysis of impact of irregularity in radionuclide coating of scaffold on the distribution of absorbed dose produced by grid of microsources

    Directory of Open Access Journals (Sweden)

    N. A. Nerosin

    2015-01-01

    Full Text Available The impact of irregularity in radionuclide coating of scaffold on the distribution of absorbed dose produced by grid of microsources was analyzed. On engineering software MATHCAD the program for calculation of absorbed dose produced by grid of microsources was created. To verify this algorithm the calculation model for MCNP code was established and represented the area consisted of soft biological tissue or any other tissue in which the grid of microsources was incorporated. Using the developed system the value of possible systematic irregular coating of radioactivity on the microsource’s core was analyzed. The distribution of activity along the surface of microsource was simulated to create distribution of absorbed dose rate corresponding to experimental data on radiation injury. The obtained model of microsource with irregular distribution of activity was compared to conventional microsource with core coated regularly along the entire area of the silver stem by main dosimetry characteristics. The results showed that even for extremely irregular distribution of activity the distribution of dose rate produced by microsource in the tumor area was not substantially different from dose-rate field obtained for microsource with regularly coated activity. The differences in dose rates (up to 10% in areas which were the nearest to the center of the grid were significantly lower than its decline from center to periphery of the grid. For spatial distribution of absorbed dose for specific configuration of microsource set and tracing of curves of equal level by selected cut-off the program SEEDPLAN was developed. The developed program represents precisely enough the spatial distribution of selected configuration set of microsources using results of calculation data for absorbed dose around the single microsource as basic data and may be used for optimal planning of brachytherapy with microsources. 

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

    Science.gov (United States)

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

    2017-12-01

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

  3. Behavioral and physiological changes produced by a supralethal dose of ionizing radiation: evidence for hormone-influenced sex differences in the rat

    International Nuclear Information System (INIS)

    Mickley, G.A.

    1980-01-01

    A sufficiently large and rapid dose of ionizing radiation produces an immediate but transient behavioral incapacitation. Acute hypotension often accompanies the disorder. Although the etiology of this syndrome is unclear, it has been suggested that an increase in histamine excretion contributes to it. Since histamine is known to interact with the endocrine system and since estrogens have been shown to prolong the life of animals exposed to potentially lethal doses of radiation, it was also hypothesized that females might be relatively less affected by an acute, large dose of ionizing radiation. Male and female rats were trained on an avoidance task, irradiated, and then retested. Females showed a less severe decrement after radiation exposure than males. Likewise, females did not suffer the severe hypotension normally associated with male radiogenic early transient incapacitation (ETI); rather, an acute hypertension was produced in females. A second series of experiments revealed that differences in male and female radiation response were eliminated by gonadectomy. Systemic estradiol injection produced strikingly feminine (i.e., superior) postirradiation avoidance responses as well as hypertension in neutered rats. Testosterone injections had no effect on either measure. Central nervous system alterations have been correlated with the ETI. Therefore, final experiments sought a possible central locus of the action of estradiol. It was found that exposure of the nucleus peopticus medialis to estrogens produces postirradiation benefits in avoidance performance and blood pressure similar to those seen after systemic estradiol treatments. Nucleus amygdaloideus medialis implants produced no such benefits

  4. High Dose Supplementation of Vitamin D Affects Measures of Systemic Inflammation: Reductions in High Sensitivity C-Reactive Protein Level and Neutrophil to Lymphocyte Ratio (NLR) Distribution.

    Science.gov (United States)

    Tabatabaeizadeh, Seyed-Amir; Avan, Amir; Bahrami, Afsane; Khodashenas, Ezzat; Esmaeili, Habibollah; Ferns, Gordon A; Abdizadeh, Mojtaba Fattahi; Ghayour-Mobarhan, Majid

    2017-12-01

    The prevalence of Vitamin D deficiency is increasing worldwide, which has be shown to be associated with increased risk of cardiovascular disease (CVD), autoimmune disease, and metabolic syndrome. These conditions are also associated with a heightened state of inflammation. The aim of the current study was to evaluate the effect of vitamin D supplementation on serum C-Reactive Protein (CRP) level and Neutrophil-to-lymphocyte ratio (NLR) distribution in a large cohort of adolescent girls. A total of 580 adolescent girls were recruited follow by evaluation of CRP and hematological parameters before and after supplementation with vitamin D supplements as 9 of 50000 IU cholecalciferol capsules for 9 weeks taken at weekly intervals. At baseline, serum hs-CRP level was 0.9 (95%CI: 0.5-1.8), while this value after intervention was reduced to 0.8 (95%CI: 0.3-1.6; P = 0.007). Similar results were also detected for NLR (e.g., NLR level was 1.66 ± 0.72 and 1.53 ± 0.67, P = 0.002, before and after therapy with compliance rate of >95.2%). Moreover, we found an association between hs-CRP and BMI, triglyceride, white blood cell count, and lymphocytes. Interestingly we observed a significant reduction in neutrophil count and CRP level after high dose vitamin D supplementation. Our findings showed that the high dose supplementation of vitamin D affects measures of systemic inflammation: reductions in High Sensitivity C-Reactive Protein level and Neutrophil-to-lymphocyte ratio (NLR) distribution. J. Cell. Biochem. 118: 4317-4322, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. The choice of individual dose criterion at which to restrict agricultural produce following an unplanned release of radioactive material to atmosphere

    International Nuclear Information System (INIS)

    Dionian, J.; Simmonds, J.R.

    1985-06-01

    In the event of an accidental release of radioactive material to atmosphere, the introduction of emergency countermeasures will be based on the need to limit the risk to individuals. However, it has been suggested that a form of cost-benefit analysis may be used as an input to decisions on the withdrawal of countermeasures, although it is recognised that these decisions may be influenced by factors other than those directly related to radiological protection. In this study, a method based on cost-benefit analysis is illustrated for assessing the optimum level of individual dose at which restrictions on agricultural production may be considered. This requires monetary values to be assigned to both the lost food production and to the health detriment, expressed as the collective effective dose equivalent commitment. It has been assumed in this analysis that food-supply restrictions are both introduced and withdrawn at the same projected level of annual individual dose. The effect on the optimum dose level of the following parameters is examined: the type of produce restricted; the size of the release; the site and direction of the release; the weather conditions; and the cost assigned to unit collective dose. It is shown that the optimum dose criterion, based on the effective dose equivalent received by an individual from a years intake of food, varies over practically the whole range of individual dose considered, i.e., 0.1 to 50 mSv. However, it is concluded that 5 mSv would represent the optimum dose criterion in a substantial number of cases. (author)

  6. Effect on therapeutic ratio of planning a boosted radiotherapy dose to the dominant intraprostatic tumour lesion within the prostate based on multifunctional MR parameters

    Science.gov (United States)

    Payne, G S; deSouza, N M; Dearnaley, D; Morgan, V A; Morgan, S C; Partridge, M

    2014-01-01

    Objective: To demonstrate the feasibility of an 8-Gy focal radiation boost to a dominant intraprostatic lesion (DIL), identified using multiparametric MRI (mpMRI), and to assess the potential outcome compared with a uniform 74-Gy prostate dose. Methods: The DIL location was predicted in 23 patients using a histopathologically verified model combining diffusion-weighted imaging, dynamic contrast-enhanced imaging, T2 maps and three-dimensional MR spectroscopic imaging. The DIL defined prior to neoadjuvant hormone downregulation was firstly registered to MRI-acquired post-hormone therapy and subsequently to CT radiotherapy scans. Intensity-modulated radiotherapy (IMRT) treatment was planned for an 8-Gy focal boost with 74-Gy dose to the remaining prostate. Areas under the dose–volume histograms (DVHs) for prostate, bladder and rectum, the tumour control probability (TCP) and normal tissue complication probabilities (NTCPs) were compared with those of the uniform 74-Gy IMRT plan. Results: Deliverable IMRT plans were feasible for all patients with identifiable DILs (20/23). Areas under the DVHs were increased for the prostate (75.1 ± 0.6 vs 72.7 ± 0.3 Gy; p < 0.001) and decreased for the rectum (38.2 ± 2.5 vs 43.5 ± 2.5 Gy; p < 0.001) and the bladder (29.1 ± 9.0 vs 36.9 ± 9.3 Gy; p < 0.001) for the boosted plan. The prostate TCP was increased (80.1 ± 1.3 vs 75.3 ± 0.9 Gy; p < 0.001) and rectal NTCP lowered (3.84 ± 3.65 vs 9.70 ± 5.68 Gy; p = 0.04) in the boosted plan. The bladder NTCP was negligible for both plans. Conclusion: Delivery of a focal boost to an mpMRI-defined DIL is feasible, and significant increases in TCP and therapeutic ratio were found. Advances in knowledge: The delivery of a focal boost to an mpMRI-defined DIL demonstrates statistically significant increases in TCP and therapeutic ratio. PMID:24601648

  7. Radioactivity in produced water from Norwegian oil and gas installations - concentrations, bioavailability and doses to marine biota

    Energy Technology Data Exchange (ETDEWEB)

    Sidhu, R.; Eriksen, D. Oe.; Straalberg, E.; Iden, K. I.; Rye, H.; Hylland, K.; Ruus, A.; Roeyset, O.; Berntssen, M. H. G.

    2006-03-15

    Substantial amounts of produced water, containing elevated levels of radionuclides (mainly 226Ra and 228Ra) are discharged to the sea as a result of oil and gas production on the Norwegian Continental Shelf. So far no study has assessed the potential radiological effects on marine biota in connection with radionuclide discharges to the North Sea. The main objective of the project is to establish radiological safe discharge limits for radium, lead and polonium associated with other components in produced water from oil and gas installations on the Norwegian continental shelf. Preliminary results indicate that presence of added chemicals such as scale inhibitors in the produced water has a marked influence on the formation of radium and barium sulphates when produced water is mixed with sea water. Thus, the mobility and bio-availability of radium (and barium) may be larger than anticipated. Also, the bio-availability of radium may be increased due to presence of such chemicals, and this is presently being studied. (author) (tk)

  8. Optimization of vitamin K antagonist drug dose finding by replacement of the international normalized ratio by a bidirectional factor : validation of a new algorithm

    NARCIS (Netherlands)

    Beinema, M J; van der Meer, F J M; Brouwers, J R B J; Rosendaal, F R

    2016-01-01

    UNLABELLED: Essentials We developed a new algorithm to optimize vitamin K antagonist dose finding. Validation was by comparing actual dosing to algorithm predictions. Predicted and actual dosing of well performing centers were highly associated. The method is promising and should be tested in a

  9. Effects of dose and scheduling on growth delay of the Lewis lung carcinoma produced by the perfluorochemical emulsion, Fluosol-DA

    International Nuclear Information System (INIS)

    Teicher, B.A.; Rose, C.M.

    1986-01-01

    The perfluorochemical emulsion, Fluosol-DA, combined with breathing a 95% oxygen/5% carbon dioxide atmosphere enhances the response of several rodent tumors. B6D2F1/J mice bearing Lewis lung tumors, measuring 50-100 mm3 were treated with 4, 8 and 12 ml/kg of Fluosol-DA intravenously each morning. Three Gy fractions twice per day were employed and carbogen breathing was maintained 1 hr prior to and during each X ray treatment. The dose modifying factors were 1.42 +/- 0.16 at 4 ml/kg, 1.85 +/- 0.23 at 8 ml/kg, and 2.17 +/- 0.34 at 12 ml/kg. In a second experiment, a single dose of Fluosol-DA (12 ml/kg) was administered on day 1 to B6D2F1/J male mice, bearing established subcutaneous Lewis lung tumors, as described above. X rays were delivered in 2, 3, or 4 Gy fractions once per day for five days. The dose modifying effect was 2.60 +/- 0.54. The effect of this treatment program was the same as that seen with single dose radiation. These experiments demonstrate that Fluosol-DA need not be administered with every fraction to produce an improved treatment outcome with fractionated X rays

  10. Enteric protection of naproxen in a fixed-dose combination product produced by hot-melt co-extrusion.

    Science.gov (United States)

    Vynckier, A-K; De Beer, M; Monteyne, T; Voorspoels, J; De Beer, T; Remon, J P; Vervaet, C

    2015-08-01

    In this study hot-melt co-extrusion is used as processing technique to manufacture a fixed-dose combination product providing enteric protection to naproxen incorporated in the core and immediate release to esomeprazole magnesium embedded in the coat. The plasticizing effect of naproxen and triethyl citrate (TEC) was tested on the enteric polymers investigated (Eudragit(®) L100-55, HPMC-AS-LF and HPMCP-HP-50). Core matrix formulations containing HPMC-AS-LF, TEC and a naproxen load of 15, 30 and 50% were processed and characterized. The in vitro naproxen release in 0.1N HCl was prevented for 2h for all formulations. The physicochemical state of the drug in the extrudates was determined and a stability study was performed. Intermolecular interactions between naproxen and polymer were identified using attenuated total reflection Fourier-transform infrared (ATR FT-IR) spectroscopy. When esomeprazole magnesium was formulated in a polyethylene oxide 100K:polyethylene glycol 4K (1:1) matrix, separated from the naproxen-containing layer, the formulation could be easily processed and complete in vitro drug release was observed after 45 min. When co-extruding the core/coat dosage form it was observed that a third layer of polymer, separating the naproxen loaded enteric formulation in the core from the coat, is required to prevent degradation of the acid-labile esomeprazole magnesium at the core/coat interface. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Effect of a single dose of pre-operative pravastatin on C-reactive protein levels and neutrophil/lymphocyte ratio in patients undergoing mastectomy for breast cancer

    Directory of Open Access Journals (Sweden)

    J.A. Morantes Acevedo

    2017-10-01

    Full Text Available Introduction: In Mexico, breast cancer is the leading cause of death from malignant tumours in women over 25 years of age. Cancer patients present pro-inflammatory status which, added to the inflammatory response to surgery, worsens their prognosis, not only from a cardiovascular perspective but also by increasing the risk of tumour relapse and the onset of metastases. The objective of this study is to determine the role of pravastatin in the modulation of the systemic inflammatory response to surgical trauma by measuring C-reactive protein (CRP levels and the neutrophil/lymphocyte ratio (NLR in breast cancer patients undergoing radical mastectomy. Methods: Randomised, single-blind, prospective clinical trial in breast cancer patients undergoing mastectomy, divided into two groups of 15 patients each. One of the groups was administered a pre-operative dose of pravastatin 20 mg and the other was not and the pre- and post-surgical inflammatory biomarker levels were measured. The numerical variables are expressed as means and with standard deviation. The comparison between groups was performed with Student's T-test. Results: A total of 30 patients subject to radical mastectomy were enrolled in the study and divided into 2 groups. The mean age was 56.9 years in the control group and 53.4 years in the pravastatin group. It was found that the patients who received a 20 mg pre-op dose of pravastatin presented less CRP elevation, with a mean of 12.6 95% CI (8.34–16.9 vs 43.8 95% CI (34.3–53.37 in the control group, p 0.0000. Although the changes in the neutrophil/lymphocyte ratio were not statistically significant, p 0.2337, it was less elevated in the pravastatin group, with a mean of 3.57 95% CI (2.02–5.11 vs 7.17 95% CI (3–17.42 in the control group. Conclusions: The pre-surgical administration of a single dose of pravastatin 20 mg significantly reduced inflammatory biomarker elevation, especially C-reactive protein

  12. SU-E-T-611: Photon and Neutron Peripheral Dose Ratio for Low (6 MV) and High (15 MV) Energy for Treatment Selection

    Energy Technology Data Exchange (ETDEWEB)

    Irazola, L; Sanchez-Doblado, F [Departamento de Fisiologia Medica y Biofisica, Universidad de Seville (Spain); Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Seville (Spain); Terron, J; Ortiz-Seidel, M [Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Seville (Spain); Departamento de Fisiologia Medica y Biofisica, Universidad de Seville (Spain); Sanchez-Nieto, B [Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago (Chile)

    2015-06-15

    Purpose: Differences between radiotherapy techniques and energies, can offer improvements in tumor coverage and organs at risk preservation. However, a more complete decision should include peripheral doses delivered to the patient. The purpose of this work is the balance of photon and neutron peripheral doses for a prostate case solved with 6 different treatment modalities. Methods: Inverse and Forward IMRT and 3D-CRT in 6 and 15 MV for a Siemens Primus linac, using the same CT data set and contours. The methodology described in [1], was used with the TNRD thermal neutron detector [2] for neutron peripheral dose estimation at 7 relevant organs (colon, esophagus, stomach, liver, lung, thyroid and skin). Photon doses were estimated for these organs by terms of the algorithm proposed in [3]. Plans were optimized with the same restrictions and limited to 30 segments in the Inverse case. Results: A similar photon peripheral dose was found comparing 6 and 15 MV cases with slightly higher values of (1.9 ± 1.6) % in mean, for the 6 MV cases. Neutron presence when using 15 MV, represents an increase in peripheral dose of (18 ± 17) % in average. Due to the higher number of MU used in Inverse IMRT, an increasing of (22 ± 3) % in neutron dose is found related to Forward and 3D-CRT plans. This corresponds to photon doses within 44 and 255 mSv along the organs, for a dose prescription of 68 Gy at the isocenter. Conclusion: Neutron and photon peripheral doses for a prostate treatment planified in 6 different techniques have been analyzed. 6 MV plans are slightly more demanding in terms of photon peripheral doses. Inverse technique in 15 MV has Result to be the most demanding one in terms of total peripheral doses, including neutrons and photons.

  13. Responses of juvenile black-tailed prairie dogs (Cynomys ludovicianus) to a commercially produced oral plague vaccine delivered at two doses

    Science.gov (United States)

    Cárdenas-Canales, Elsa M.; Wolfe, Lisa L.; Tripp. Daniel W.,; Rocke, Tonie E.; Abbott, Rachel C.; Miller, Michael W.

    2017-01-01

    We confirmed safety and immunogenicity of mass-produced vaccine baits carrying an experimental, commercial-source plague vaccine (RCN-F1/V307) expressing Yersinia pestis V and F1 antigens. Forty-five juvenile black-tailed prairie dogs (Cynomys ludovicianus) were randomly divided into three treatment groups (n=15 animals/group). Animals in the first group received one standard-dose vaccine bait (5×107 plaque-forming units [pfu]; STD). The second group received a lower-dose bait (1×107 pfu; LOW). In the third group, five animals received two standard-dose baits and 10 were left untreated but in contact. Two vaccine-treated and one untreated prairie dogs died during the study, but laboratory analyses ruled out vaccine involvement. Overall, 17 of 33 (52%; 95% confidence interval for binomial proportion [bCI] 34−69%) prairie dogs receiving vaccine-laden bait showed a positive anti-V antibody response on at least one sampling occasion after bait consumption, and eight (24%; bCI 11–42%) showed sustained antibody responses. The STD and LOW groups did not differ (P≥0.78) in their proportions of overall or sustained antibody responses after vaccine bait consumption. Serum from one of the nine (11%; bCI 0.3–48%) surviving untreated, in-contact prairie dogs also had detectable antibody on one sampling occasion. We did not observe any adverse effects related to oral vaccination.

  14. Responses of Juvenile Black-tailed Prairie Dogs ( Cynomys ludovicianus ) to a Commercially Produced Oral Plague Vaccine Delivered at Two Doses.

    Science.gov (United States)

    Cárdenas-Canales, Elsa M; Wolfe, Lisa L; Tripp, Daniel W; Rocke, Tonie E; Abbott, Rachel C; Miller, Michael W

    2017-10-01

    We confirmed safety and immunogenicity of mass-produced vaccine baits carrying an experimental, commercial-source plague vaccine (RCN-F1/V307) expressing Yersinia pestis V and F1 antigens. Forty-five juvenile black-tailed prairie dogs ( Cynomys ludovicianus ) were randomly divided into three treatment groups (n=15 animals/group). Animals in the first group received one standard-dose vaccine bait (5×10 7 plaque-forming units [pfu]; STD). The second group received a lower-dose bait (1×10 7 pfu; LOW). In the third group, five animals received two standard-dose baits and 10 were left untreated but in contact. Two vaccine-treated and one untreated prairie dogs died during the study, but laboratory analyses ruled out vaccine involvement. Overall, 17 of 33 (52%; 95% confidence interval for binomial proportion [bCI] 34-69%) prairie dogs receiving vaccine-laden bait showed a positive anti-V antibody response on at least one sampling occasion after bait consumption, and eight (24%; bCI 11-42%) showed sustained antibody responses. The STD and LOW groups did not differ (P≥0.78) in their proportions of overall or sustained antibody responses after vaccine bait consumption. Serum from one of the nine (11%; bCI 0.3-48%) surviving untreated, in-contact prairie dogs also had detectable antibody on one sampling occasion. We did not observe any adverse effects related to oral vaccination.

  15. Determination of water, hydrogen, and carbon content of Korean main farm produces for the calculation of H-3 and C-14 ingestion dose

    International Nuclear Information System (INIS)

    Chung, Yang Geun; Lee, Gab Bock; Kim, Mi Ja; Eum, Hee Moon

    2003-01-01

    Water, hydrogen, and carbon content of grains, leafy vegetable, root vegetable, and fruits in Korea were determined to be used in the calculation of HTO, OBT, C-14 offsite ingestion dose. The individual items and the weighting factors of the 4 groups were based on the results of nationwide dietary intake survey in Korea. Items produced in an island or imported were excluded for the reason that they would not be affected directly by the nuclear power plants in the nation. On the same assumption, cooked and instant foods also were excluded. Items within 95% of the cumulative percentage of intake in each category were selected as the main farm produces, and then each intake percentage was taken as the weighting factor. Water, Hydrogen, and carbon content were determined using the data in Food Composition TABLE of Korea. H and C content were calculated from protein, fat, and carbohydrate content in the TABLE, and multiplied by each weighting factor to make the group-representative value. Grains, lefty and root vegetable, and fruits of Korea had 11.0%, 93.6%, 87.9%, 86.2% of water, 5.6%, 0.4%. 0.7%, 0.9% of hydrogen, and 39.6%, 2.5%, 5.2%, 6.0% of carbon, respectively. This is different from those in the ODCM from AECL data. Over ODCM, water content of grains and vegetable were 0.92-0.98 times ODCM, and fruits 1.03 times ODCM, which would result in the change of HTO ingestion dose as much. Hydrogen content of grains and vegetables are 1.02-2.33 times ODCM, but fruits 0.9 times ODCM. Carbon content of grains, leafy vegetables, and fruits are 0.7-0.98 times ODCM, but root vegetables 1.49 times ODCM. This would result in the change of ingestion dose as much

  16. Plastic Models Designed to Produce Large Height-to-Length Ratio Steady-State Planar and Axisymmetric (Radial) Viscous Liquid Laminar Flow Gravity Currents

    Science.gov (United States)

    Blanck, Harvey F.

    2012-01-01

    Naturally occurring gravity currents include events such as air flowing through an open front door, a volcanic eruption's pyroclastic flow down a mountainside, and the spread of the Bhopal disaster's methyl isocyanate gas. Gravity currents typically have a small height-to-distance ratio. Plastic models were designed and constructed with a…

  17. Effects of climate on organic carbon and the ratio of planktonic to benthic primary producers in a subarctic lake during the past 45 years

    NARCIS (Netherlands)

    Rosén, Peter; Cunningham, Laura; Vonk, Jorien; Karlsson, Jan

    The effects of climatic variables on lake-water total organic carbon (TOC) concentrations and benthic and pelagic primary producers during the past 45 yr were assessed using the sediment records of two subarctic lakes, one with mires and one without mires connected to the lake. The lake with a mire

  18. Dosimetric characterization of low dose rate Iridium 192 wires used in interstitial brachytherapy, produced by Brachytherapy Sources Laboratory the CTRS/IPEN/CNEN-SP, Brazil

    International Nuclear Information System (INIS)

    Silva, Marco Antonio da

    2003-01-01

    In this work they were some dosimetric parameters established by the dosimetry protocol AAPM TG-43 for the thread of 192 Ir with the purpose of complementing the dosimetric specifications of an original source produced at the country. For so much quantities such as the constant of dose rate, A , function of radial dose, g(r), and anisotropy function, F(r,θ), they were experimentally determined and the geometry function, G(r,θ), it was calculated. Measurements with TLD of LiF, with dimensions of 1 mm X 1 mm X 1 mm, was made in a phantom made of 5 plates of solid water RW3 material with dimensions of 300 mm X 300 mm X 10 mm, where it was obtained values of dose rate for some radial distances of the source, between 10 and 100 mm, to for an angle of 90 deg, for g(r), and also for other angles between 0 deg and 180 deg for F(r,θ). Threads of 192 Ir were studied in the lengths of 10 mm, 20 mm, 30 mm, 50 mm and 100 mm. The stored energy on the thermoluminescent dosimeters was integrated by means of a TLD reader Harshaw 2000 meantime into a cycle of thermal treatment to which the thermoluminescent dosimeters was submitted being, 400 C in an interval of time of 1 hour proceeded immediately for more 2 hours to 105 C, after this treatment the thermoluminescent dosimeters was irradiated; even so, before the reading the detectors was still warm to 105 deg C for 10 minutes. The constant of dose rate for the threads of 192 Ir of 10 mm, 20 mm, 30 mm, 50 mm and 100 mm are (1,076 =- 3,7%); (0,931 =- 3,7%); (0,714 =- 3,7%); (0,589 =-3,7%) and (0,271 =- 3,7%) cGyh -1 U -1 , respectively (1U = unit of kerma intensity in the air = 1mGy m 2 h -1 = 1cGy cm 2 h -1 ). The results obtained for g(r) and F(r,θ) have uncertainties of (=- 4,5%) and they are compared with values obtained by Monte Carlo simulation and also for other values presented in the literature. (author)

  19. Investigation on the effect of blending ratio and airflow rate on syngas profile produced from co-gasification of blended feedstock

    Directory of Open Access Journals (Sweden)

    Inayat Muddasser

    2017-01-01

    Full Text Available Shortages of feedstock supply due to seasonal availability, high transportation costs, and lack of biomass market are creating serious problems in continues operation of bioenergy industry. Aiming at this problem, utilization of blended feedstock is proposed. In this work blends of two different biomasses (wood and coconut shells were co-gasified using externally heated downdraft gasifier. The effects of varying biomass blending ratio and airflow rate on gaseous components of syngas and its heating value were investigated. The results obtained from the experiments revealed that W20:CS80 blend yielded higher values for H2 (20 Vol.% and HHV (18 MJ/Nm3 as compared to the other blends. The higher airflow rate has a negative effect on syngas profile and heating value. The CO and CH4 were observed higher at the start of the process, however, CO was observed decreasing afterward, and the CH4 dropped to 5.0 Vol.%. The maximum H2 and CH4 were obtained at 2.5 LPM airflow rate. The process was noticed more stable at low air flow rates. The HHV was observed higher at the start of process at low airflow rate. It is concluded that low airflow rate and a higher ratio of coconut shells can improve the syngas quality during co-gasification.

  20. Maximizing the Benefit-Cost Ratio of Anthracyclines in Metastatic Breast Cancer: Case Report of a Patient with a Complete Response to High-Dose Doxorubicin

    Directory of Open Access Journals (Sweden)

    Kevin Shee

    2016-12-01

    Full Text Available Despite the clinical efficacy of anthracycline agents such as doxorubicin, dose-limiting cardiac toxicities significantly limit their long-term use. Here, we present the case of a 33-year-old female patient with extensive metastatic ER+/PR+/HER2– mucinous adenocarcinoma of the breast, who was started on doxorubicin/cyclophosphamide therapy after progressing on paclitaxel and ovarian suppressor goserelin with aromatase inhibitor exemestane. The patient was comanaged by cardiology, who carefully monitored measures of cardiac function, including EKGs, serial echocardiograms, and profiling of lipids, troponin, and pro-BNP every 2 months. The patient was treated with the cardioprotective agent dexrazoxane, and changes in cardiac markers [e.g. decreases in ejection fraction (EF] were immediately addressed by therapeutic intervention with the ACE inhibitor lisinopril and beta-blocker metoprolol. The patient had a complete response to doxorubicin therapy, with a cumulative dose of 1,350 mg/m2, which is significantly above the recommended limits, and to our knowledge, the highest dose reported in literature. Two and a half years after the last doxorubicin cycle, the patient is asymptomatic with no cardiotoxicity and an excellent quality of life. This case highlights the importance of careful monitoring and management of doxorubicin-mediated cardiotoxicity, and that higher cumulative doses of anthracyclines can be considered in patients with ongoing clinical benefit.

  1. Maximizing the Benefit-Cost Ratio of Anthracyclines in Metastatic Breast Cancer: Case Report of a Patient with a Complete Response to High-Dose Doxorubicin.

    Science.gov (United States)

    Shee, Kevin; Kono, Alan T; D'Anna, Susan P; Seltzer, Mark A; Lu, Xiaoying; Miller, Todd W; Chamberlin, Mary D

    2016-01-01

    Despite the clinical efficacy of anthracycline agents such as doxorubicin, dose-limiting cardiac toxicities significantly limit their long-term use. Here, we present the case of a 33-year-old female patient with extensive metastatic ER+/PR+/HER2- mucinous adenocarcinoma of the breast, who was started on doxorubicin/cyclophosphamide therapy after progressing on paclitaxel and ovarian suppressor goserelin with aromatase inhibitor exemestane. The patient was comanaged by cardiology, who carefully monitored measures of cardiac function, including EKGs, serial echocardiograms, and profiling of lipids, troponin, and pro-BNP every 2 months. The patient was treated with the cardioprotective agent dexrazoxane, and changes in cardiac markers [e.g. decreases in ejection fraction (EF)] were immediately addressed by therapeutic intervention with the ACE inhibitor lisinopril and beta-blocker metoprolol. The patient had a complete response to doxorubicin therapy, with a cumulative dose of 1,350 mg/m 2 , which is significantly above the recommended limits, and to our knowledge, the highest dose reported in literature. Two and a half years after the last doxorubicin cycle, the patient is asymptomatic with no cardiotoxicity and an excellent quality of life. This case highlights the importance of careful monitoring and management of doxorubicin-mediated cardiotoxicity, and that higher cumulative doses of anthracyclines can be considered in patients with ongoing clinical benefit.

  2. Influence of a modification of the petcoke/coal ratio on the leachability of fly ash and slag produced from a large PCC power plant.

    Science.gov (United States)

    Izquierdo, Maria; Font, Oriol; Moreno, Natalia; Querol, Xavier; Huggins, Frank E; Alvarez, Esther; Diez, Sergi; Otero, Pedro; Ballesteros, Juan Carlos; Gimenez, Antonio

    2007-08-01

    Co-firing of coal with inexpensive secondary fuels such as petroleum coke is expected to increase in the near future in the EU given that it may provide certain economic and environmental benefits with respect to coal combustion. However, changes in the feed fuel composition of power plants may modify the bulk content and the speciation of a number of elements in fly ash and slag. Consequently, leachability of these byproducts also can be modified. This study is focused on identifying the changes in the environmental quality of co-fired fly ash and slag induced by a modification of the petcoke/coal ratio. Petcoke was found to increase the leachable content of V and Mo and to enhance the mobility of S and As. However, with the exception of these elements, the addition of this secondary fuel did not drastically modify the bulk composition or the overall leachability of the resulting fly ash and slag.

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

    DEFF Research Database (Denmark)

    Owusu-Ansah, Emmanuel de-Graft Johnson; Sampson, Angelina; Amponsah, Samuel K.

    2017-01-01

    The need to replace the commonly applied fecal indicator conversions ratio (an assumption of 1:10− 5 virus to fecal indicator organism) in Quantitative Microbial Risk Assessment (QMRA) with models based on quantitative data on the virus of interest has gained prominence due to the different physi...

  4. Assessment of the immunocrit ratio assay for evaluation of colostrum quality in sows induced to farrow and inseminated using single dose fixed time insemination

    Science.gov (United States)

    Problem Statement: Sufficient intake of quality colostrum is essential for the success of newborn piglets. Relatively high levels of immunoglobulins (Ig) generally indicate colostrum of high quality. IgG is the predominant Ig in colostrum. The immunocrit ratio assay has been developed as a simple me...

  5. High dose vitamin C supplementation increases the Th1/Th2 cytokine secretion ratio, but decreases eosinophilic infiltration in bronchoalveolar lavage fluid of ovalbumin-sensitized and challenged mice.

    Science.gov (United States)

    Chang, Hui-Hsiang; Chen, Chin-Shuh; Lin, Jin-Yuarn

    2009-11-11

    Vitamin C is traditionally regarded to be beneficial for asthma, however the benefit is still controversial. In the present study, high dose vitamin C was supplemented to ovalbumin (OVA)-sensitized and challenged mice to evaluate the effects of dietary vitamin C on allergic asthma. In this study, the experimental mice were divided into four groups, including nonsensitized control, dietary control, positive control (cured ip with dexamethasone), and high dose vitamin C supplementation (130 mg of vitamin C/kg bw/day by gavage for 5 weeks). Differential leukocyte counts, levels of inflammatory mediators, as well as type 1 T-helper lymphocytes (Th1)-type and type 2 T-helper lymphocytes (Th2)-type cytokines in the bronchoalveolar lavage fluid (BALF) were determined. The results showed that both high dose vitamin C supplementation and dexamethasone treatments significantly (P < 0.05) decreased eosinophilic infiltration into BALF. High dose vitamin C supplementation significantly increased the secretion ratio of interferon (IFN)-gamma/interleukin (IL)-5 cytokines. This study suggests that high dose vitamin C supplementation might attenuate allergic inflammation in vivo via modulating the Th1/Th2 balance toward the Th1 pole during the Th2-skewed allergic airway inflammation and decreasing eosinophilic infiltration into BALF.

  6. Assessment of radionuclide concentration and absorbed dose from consumption of community water supplies in oil and gas producing areas in delta State Nigeria

    International Nuclear Information System (INIS)

    Tchokossa, P.; Olomo, J.B.; Balogun, F.A.

    2010-01-01

    A survey of radioactivity concentration in water supplies used for domestic and industrial purposes in the oil and gas producing communities of Delta State, Nigeria was carried out using a well-calibrated High-Purity Germanium (HPGe) detector system. The study area was partitioned into ten sections and a total of two samples per partition were collected for analysis. Samples of water from a non-producing area 14 were also collected as control. In all, a total number of forty three samples were collected and analyzed. Each sample was acidified at the rate of 10 ml of 11 M HCI per litre of water to prevent the absorption of radionuclides into the wall of the container and sealed in a properly cleaned container for at least one month so as to attain a state of secular radioactive equilibrium before analysis. The photo peaks observed with reliable regularity belong to the naturally occurring series-decay radionuclide headed by 238U and 232Th, as well as the non-series decay type 40K. The mean specific activity obtained for 40K was 49.15±15.35 BqL-1 with a range of 6.03 and 177.04 Bq L-1 while for 226Ra, the mean specific activity was 3.36±1.28 Bq L-1 with a range of 1.29 and 12.08 BqL-1 and the mean specific activity for 228Ra was 3.21± 2.69 BqL-1 with a range of 1.61 and 9.83 BqL-1 and the total annual effective dose did not show any significant health impact. (author)

  7. The ratio between effective doses due to external exposure to electrons for tomographic and mathematical models; Razoes entre doses efetivas devido a exposicao externa de eletrons para modelos tomograficos e matematicos

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Fernando R.A. [Centro Regional de Ciencias Nucleares (CRCN), Recife, PE (Brazil)]|[Faculdade Boa Viagem (FBV), Recife, PE (Brazil)]. E-mail: falima@cnen.gov.br; Kramer, Richard; Khoury, Helen J. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear]. E-mail: rkramer@uol.com.br; hjkhoury@globo.com; Vieira, Jose W. [Centro Federal de Educacao Tecnologica de Pernambuco (CEFET-PE), Recife, PE (Brazil)]. E-mail: jwvieira@br.inter.net; Yoriyaz, Helio [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: hyotiyaz@ipen.br; Loureiro, Eduardo C.M. [Universidade de Pernambuco, Recife, PE (Brazil). Escola Politecnica (POLI/UPE)]. E-mail: eduloureiro@uol.com.br

    2005-07-01

    The development of new, sophisticated Monte Carlo codes, and of tomographic or voxel based human phantoms motivated the International Commission on Radiological Protection (ICRP) to call for a revision of traditional exposure models, which have been used in the past to calculate organ and tissue as well as effective dose coefficients for stylized MIRD5- type phantoms. This paper reports about calculations made with the recently developed tomographic MAX (Male Adult voXel) and FAX (Female Adult voXel) phantoms, as well as with the gender-specific MIRD5-type phantoms ADAM and EVA, coupled to the EGS4 and to the MCNP4C Monte Carlo code, for external whole-body irradiation with electrons. Effective doses for the tomographic and for the stylized exposure models will be compared separately as function of the replacement of the Monte Carlo code, of human tissue compositions, and of the stylized by the tomographic anatomy. The results indicate that for external exposures to electrons the introduction of voxel-based exposure models causes changes of the effective dose between +40% and - 60% depending on the energies and geometries considered compared to corresponding data of the MIRD5-type phantoms. (author)

  8. The ratio between effective doses for tomographic and mathematical models of internal exposures to electrons; Razoes entre as doses efetivas para modelos tomograficos e matematicos em exposicoes internas a eletrons

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Richard; Khoury, Helen J. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear]. E-mail: rkramer@uol.com.br; hjkhoury@globo.com; Lima, Fernando R.A. [Centro Regional de Ciencias Nucleares (CRCN), Recife, PE (Brazil)]|[Faculdade Boa Viagem (FBV), Recife, PE (Brazil)]. E-mail: falima@cnen.gov.br; Vieira, Jose W. [Centro Federal de Educacao Tecnologica de Pernambuco (CEFET-PE), Recife, PE (Brazil)]. E-mail: jwvieira@br.inter.net; Loureiro, Eduardo C.M. [Universidade de Pernambuco, Recife, PE (Brazil). Escola Politecnica (POLI/UPE)]. E-mail: eduloureiro@uol.com.br

    2005-07-01

    The development of new, sophisticated Monte Carlo codes, and of tomographic or voxel based human phantoms motivated the International Commission on Radiological Protection (ICRP) to call for a revision of traditional exposure models, which have been used in the past to calculate organ and tissue as well as effective dose coefficients for stylized MIRD5-type phantoms. This paper reports about calculations made with the recently developed tomographic MAX (Male Adult voXel) and FAX (Female Adult voXel) phantoms, as well as with the gender specific MIRD-type phantoms ADAM and EVA, coupled to the EGS4 Monte Carlo code, for internal exposures to electrons with energies between 100 keV and 4 MeV for various source organs. Effective doses for the tomographic and for the stylized exposure models will be compared separately as function of the replacement of the Monte Carlo code, of human tissue compositions, and of the stylized by the tomographic anatomy. The results indicate that for internal exposures to electrons the introduction of voxel-based exposure models causes changes of the effective dose between +20% and - 40% depending on the energies and source organs considered compared to corresponding data of the MIRD5-type phantoms. (author)

  9. Ratios between effective doses for tomographic and mathematician models due to internal exposure of photons; Razoes entre doses efetivas para modelos tomograficos e modelos matematicos devido as exposicoes internas de fotons

    Energy Technology Data Exchange (ETDEWEB)

    Lima, F.R.A. [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Kramer, R.; Khoury, H.J.; Santos, A.M. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Vieira, W. [Centro Federal de Educacao Tecnologica de Pernambuco (CEFET-PE), Recife, PE (Brazil); Loureiro, E.C.M. [Escola Politecnica de Pernambuco, Recife, PE (Brazil)

    2005-07-01

    The development of new and sophisticated Monte Carlo codes and tomographic human phantoms or voxels motivated the International Commission on Radiological Protection (ICRP) to revise the traditional models of exposure, which have been used to calculate effective dose coefficients for organs and tissues based on mathematician phantoms known as MIRD5. This paper shows the results of calculations using tomographic phantoms MAX (Male Adult voXel) and FAX (Female Adult voXel), recently developed by the authors as well as with the phantoms ADAM and EVA, of specific genres, type MIRD5, coupled to the EGS4 Monte Carlo and MCNP4C codes, for internal exposure with photons of energies between 10 keV and 4 MeV to several organs sources. Effective Doses for both models, tomographic and mathematician, will be compared separately as a function of the Monte Carlo code replacement, of compositions of human tissues and the anatomy reproduced through tomographs. The results indicate that for photon internal exposure, the use of models of exposure based in voxel, increases the values of effective doses up to 70% for some organs sources considered in this study, when compared with the corresponding results obtained with phantoms of MIRD-5 type.

  10. Reductions in milk Δ9-desaturation ratios to oral dosing of cobalt-acetate are accompanied by the downregulation of SCD1 in lactating ewes.

    Science.gov (United States)

    Toral, P G; Hervás, G; Frutos, P

    2015-03-01

    Oral administration of cobalt has been proven to alter milk fatty acid (FA) composition consistent with an inhibition of mammary stearoyl-coenzyme A desaturase (SCD) activity in ruminants, but the mechanisms explaining its mode of action remain uncertain. In this study, Co (as Co-acetate) was dosed to lactating ewes with the aims of examining mammary gene expression during Co-induced changes in milk FA composition, and estimating the endogenous synthesis of SCD products in milk of sheep fed an 18:3n-3-enriched diet. Twelve Assaf ewes fed a diet supplemented with 2% linseed oil were allocated to 2 experimental groups and received an oral drench supplying either 0 (control) or 9 mg of Co/kg of body weight per day. Treatments were administered in 3 equal doses at 8-h intervals for 6 d. No effects of Co administration on animal performance were observed. The changes in milk FA (namely, reductions in most cis-9-containing FA) were consistent with an inhibition of SCD in the absence of detectable effects on the relative importance of mammary de novo synthesis and FA uptake. The high proportion of endogenous cis-9 trans-11 18:2 observed in this study (89%) would agree with a greater supply of trans-11 18:1 of ruminal origin in ewes fed linseed oil, compared with previous estimates in sheep fed a diet without lipid supplementation. Differences between studies could also be related to diet-induced changes in SCD activity. Altogether, both mechanisms would support that basal diet composition is a major determinant of the relative contribution of Δ9-desaturation to milk FA profile. Similarly, the consumption of a diet rich in 18:3n-3 might also explain the low proportion of milk cis-9 18:1 estimated to derive from Δ9-desaturation (29%). The administration of Co to ewes fed linseed oil allowed to discriminate minor 18:3 isomers in milk, such as cis-9 trans-12 cis-15 18:3, as SCD products. Finally, Co dosing lowered the mRNA abundance of SCD1 in the mammary secretory tissue

  11. Development of a novel pelletization technique through an extremely high-shear process using a mechanical powder processor to produce high-dose small core granules suitable for film coating.

    Science.gov (United States)

    Kondo, Keita; Kato, Aya; Niwa, Toshiyuki

    2015-04-10

    We established an extremely high-shear melt pelletization technique using a mechanical powder processor to produce high-dose granules smaller than 300 μm with properties suitable for film coating. A mixture of ethenzamide and polyethylene glycol (used as a low-melting binder) at various weight ratios was mechanically treated under various jacket temperatures. When the jacket temperature was set to 50 °C or greater, the product temperature reached the melting point of the binder, resulting in pelletization. The drug powder were pelletized with a small amount of binder to yield pellets of approximately 150 μm with a drug content of more than 90%. The mechanism of melt pelletization through ultrahigh shearing involves a series of nucleation, consolidation, coalescence and breakage stages. The power consumption profile corresponding to each stage in the pelletization revealed that pellets between 75 and 300 μm were effectively obtained at a large power consumption peak. The resultant pellets showed comparative sphericity and smoothness, and higher durability than commercial core granules for film coating. In conclusion, this study demonstrates that the extremely high-shear melt pelletization technique can give drug pellets with desirable properties as core particles for the coating process. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Dose-response evaluation of the standardized ileal digestible tryptophan : lysine ratio to maximize growth performance of growing-finishing gilts under commercial conditions.

    Science.gov (United States)

    Gonçalves, M A D; Tokach, M D; Bello, N M; Touchette, K J; Goodband, R D; DeRouchey, J M; Woodworth, J C; Dritz, S S

    2017-11-16

    Environmental regulations as well as economic incentives have resulted in greater use of synthetic amino acids in swine diets. Tryptophan is typically the second limiting amino acid in corn-soybean meal-based diets. However, using corn-based co-products emphasizes the need to evaluate the pig's response to increasing Trp concentrations. Therefore, the objective of these studies was to evaluate the dose-response to increasing standardized ileal digestible (SID) Trp : Lys on growth performance of growing-finishing gilts housed under large-scale commercial conditions. Dietary treatments consisted of SID Trp : Lys of 14.5%, 16.5%, 18.0%, 19.5%, 21.0%, 22.5% and 24.5%. The study was conducted in four experiments of 21 days of duration each, and used corn-soybean meal-based diets with 30% distillers dried grains with solubles. A total of 1166, 1099, 1132 and 975 gilts (PIC 337×1050, initially 29.9±2.0 kg, 55.5±4.8 kg, 71.2±3.4 kg and 106.2±3.1 kg BW, mean±SD) were used. Within each experiment, pens of gilts were blocked by BW and assigned to one of the seven dietary treatments and six pens per treatment with 20 to 28 gilts/pen. First, generalized linear mixed models were fit to data from each experiment to characterize performance. Next, data were modeled across experiments and fit competing dose-response linear and non-linear models and estimate SID Trp : Lys break points or maximums for performance. Competing models included broken-line linear (BLL), broken-line quadratic and quadratic polynomial (QP). For average daily gain (ADG), increasing the SID Trp : Lys increased growth rate in a quadratic manner (Pgilts ranged from a minimum of 16.9% for maximum G : F to 23.5% for maximum ADG.

  13. The Ginkgo biloba extract (GbE) protects the kidney from damage produced by a single and low dose of carbon tetrachloride in adult male rats.

    Science.gov (United States)

    Chávez-Morales, R M; Jaramillo-Juárez, F; Rodríguez-Vázquez, M L; Martínez-Saldaña, M C; Del Río, F A Posadas; Garfias-López, J A

    2017-09-05

    Gingko biloba leaves have been used as herbal medicine in China for 5000 years, and the standardized leaf extract (GB-STE) has some beneficial effects in the treatment of age-related, cardiovascular, and neurological diseases. The aim of this study was to investigate the renoprotective effects of the Gingko biloba extract (GbE) against the toxicity of a single and relatively low dose of carbon tetrachloride (CCl 4 ). In male adult Wistar rats, we determined the urine flux, the concentration of total proteins in urine, the concentration of glucose in urine, and the concentration of malondialdehyde (MDA) in renal cortex as well as two markers of renal function (clearance of inulin and p-aminohippurate); we also compared the histological lesions caused by CCl 4 . Carbon tetrachloride increased the urinary concentration of total proteins, and the renal concentration of MDA; however, it did not modify the urine flux, urinary concentration of glucose, nor the inuline or the p-aminohipurate clearances. Morphologically, CCl 4 generated some tubular damage that was more intense in the inner cortex of kidneys. The GbE extract counteracted the effects of CCl 4 on the concentration of total proteins in urine, the concentration of renal MDA, and the renal histological changes. In conclusion the main toxic effects produced by CCl 4 were prevented by the GbE, probably due to their antioxidant properties and the inhibition of the main P450 isoenzyme (CYP2E1) that metabolize CCl 4 . Copyright © 2017 Elsevier GmbH. All rights reserved.

  14. Clenbuterol Residues in Plasma and Urine Samples of Food-Producing Pigs During and After Subchronic Exposure to a Growth-Promoting Dose

    Directory of Open Access Journals (Sweden)

    Tihomira Gojmerac

    2009-01-01

    Full Text Available The aim of the study is to evaluate the suitability of plasma and urine as matrices for clenbuterol residue determination during and after its subchronic administration at a growth-promoting dose to male pigs, using previously validated enzyme-linked immunosorbent assay (ELISA as a screening method and liquid chromatography tandem mass spectrometry (LC-MS/MS as a confirmation method. A high correlation coefficient between these analytical methods was obtained for both urine (R=0.9800 and plasma (R=0.9970 concentrations. Study results show the plasma and urine concentration to vary greatly during oral treatment with clenbuterol for 28 days. The peak urine concentration ((88.54±50.54 ng/mL recorded on day 21 was 40-fold peak plasma concentration ((2.25±1.54 ng/mL. After withdrawal period, the peak urine clenbuterol concentration ((42.93±10.52 ng/mL recorded on day 0 was 24-fold plasma concentration ((1.79±0.97 ng/mL. The maximum allowed concentration of 0.5 ng/g in the liver as a regulated matrix for control of clenbuterol abuse was achieved in plasma on day 3 ((0.52±0.26 ng/mL and in urine on day 7 of treatment withdrawal ((0.45±0.11 ng/mL. Study results indicate that urine and plasma may be suitable matrices for the control of clenbuterol abuse during fattening of food-producing pigs but have a limited value because of the rapidly decreasing concentration upon treatment withdrawal, in plasma in particular.

  15. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer.

    Science.gov (United States)

    Razak, Rafiza Abdul; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Ismail, Khairul Nizar; Hardjito, Djwantoro; Yahya, Zarina

    2015-05-21

    This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

  16. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

    Directory of Open Access Journals (Sweden)

    Rafiza Abdul Razak

    2015-05-01

    Full Text Available This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA using LUSI (Sidoarjo mud and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

  17. Scavenging ratios

    International Nuclear Information System (INIS)

    Krey, P.W.; Toonkel, L.E.

    1977-01-01

    Total 90 Sr fallout is adjusted for dry deposition, and scavenging ratios are calculated at Seattle, New York, and Fayetteville, Ark. Stable-lead scavenging ratios are also presented for New York. These ratios show large scatter, but average values are generally inversely proportional to precipitation. Stable-lead ratios decrease more rapidly with precipitation than do those of 90 Sr, a decrease reflecting a lesser availability of lead to the scavenging processes

  18. Golden Ratio

    Indian Academy of Sciences (India)

    Our attraction to another body increases if the body is symmetricaland in proportion. If a face or a structure is in proportion,we are more likely to notice it and find it beautiful.The universal ratio of beauty is the 'Golden Ratio', found inmany structures. This ratio comes from Fibonacci numbers.In this article, we explore this ...

  19. Evaluation of warfarin management with international normalized ratio self-testing and online remote monitoring and management plus low-dose vitamin k with genomic considerations: a pilot study.

    Science.gov (United States)

    Bussey, Henry I; Bussey, Marie; Bussey-Smith, Kristin L; Frei, Christopher R

    2013-11-01

    As better international normalized ratio (INR) control and self-testing reduce events in warfarin-treated patients, and vitamin K supplementation may improve INR control, our primary objective was to evaluate the effect of a system combining frequent INR self-testing with online remote monitoring and management (STORM₂) and low-dose vitamin K supplementation on INR control; our secondary objectives were to assess the impact of STORM₂ on clinician time and to evaluate the influence of pharmacogenomics on INR stability and warfarin dose after vitamin K supplementation. Prospective pre- and postintervention study. Freestanding clinical research center. Fifty-five patients treated with long-term warfarin therapy who were referred from four anticoagulation clinics and seven medical practices. All patients performed weekly INR self-testing and received vitamin K 100 µg/day and online anticoagulation management for 1 year. INR control and time required for anticoagulation management were assessed, and an analysis of warfarin dosing and INR stability by genetic polymorphism subgroup (vitamin K epoxide reductase complex 1 [VKORC1] and cytochrome P450 2C9 isoenzyme) was performed; vitamin K product content was also analyzed. The percentage of time that the INR is within the time in therapeutic range (TTR) improved from 56% before the intervention to 81% after the intervention (pmanaged warfarin and with the new oral anticoagulants. © 2013 Pharmacotherapy Publications, Inc.

  20. A combustion setup to precisely reference δ13C and δ2H isotope ratios of pure CH4 to produce isotope reference gases of δ13C-CH4 in synthetic air

    Directory of Open Access Journals (Sweden)

    H. Schaefer

    2012-09-01

    Full Text Available Isotope records of atmospheric CH4 can be used to infer changes in the biogeochemistry of CH4. One factor currently limiting the quantitative interpretation of such changes are uncertainties in the isotope measurements stemming from the lack of a unique isotope reference gas, certified for δ13C-CH4 or δ2H-CH4. We present a method to produce isotope reference gases for CH4 in synthetic air that are precisely anchored to the VPDB and VSMOW scales and have δ13C-CH4 values typical for the modern and glacial atmosphere. We quantitatively combusted two pure CH4 gases from fossil and biogenic sources and determined the δ13C and δ2H values of the produced CO2 and H2O relative to the VPDB and VSMOW scales within a very small analytical uncertainty of 0.04‰ and 0.7‰, respectively. We found isotope ratios of −39.56‰ and −56.37‰ for δ13C and −170.1‰ and −317.4‰ for δ2H in the fossil and biogenic CH4, respectively. We used both CH4 types as parental gases from which we mixed two filial CH4 gases. Their δ13C was determined to be −42.21‰ and −47.25‰ representing glacial and present atmospheric δ13C-CH4. The δ2H isotope ratios of the filial CH4 gases were found to be −193.1‰ and −237.1‰, respectively. Next, we mixed aliquots of the filial CH4 gases with ultrapure N2/O2 (CH4 ≤ 2 ppb producing two isotope reference gases of synthetic air with CH4 mixing ratios near atmospheric values. We show that our method is reproducible and does not introduce isotopic fractionation for δ13C within the uncertainties of our detection limit (we cannot conclude this for δ2H because our system is currently not prepared for δ2H-CH4 measurements in air samples. The general principle of our method can be applied to produce synthetic isotope reference gases targeting δ2H-CH4 or other gas species.

  1. Ratio and rate effects of 32P-triple superphosphate and phosphate rock mixtures on corn growth Proporções e doses das misturas de 32P-superfosfato triplo com fosfato natural no desenvolvimento do milho

    Directory of Open Access Journals (Sweden)

    Vinícius Ide Franzini

    2009-02-01

    Full Text Available The availability of phosphorus (P from " Patos de Minas" phosphate rock (PR can be improved if it is applied mixed with a water-soluble P source. The objective of this study was to evaluate 32P as a tracer to quantify the effect of the ratio of mixtures of triple superphosphate (TSP with PR and the rates of application on P availability from PR. Two experiments were conducted in a greenhouse utilizing corn (Zea mays L. plants as test crop. In the first experiment, the P sources were applied at the rate of 90 mg P kg-1 soil either separately or as compacted mixtures in several TSP:PR ratios (100:0, 80:20, 60:40, 50:50, 40:60, 20:80 and 0:100 calculated on the basis of the total P content. In the second experiment, the TSP was applied alone or as 50:50 compacted mixtures with PR applied at four P rates (15, 30, 60 and 90 mg P kg-1 while the sole PR treatment was applied at the 90 mg kg-1 P rate . The mixture of PR with TSP improved the P recovery from PR in the corn plant and this effect increased proportionally to the TSP amounts in the mixture. When compared with the plant P recovery from TSP (10.52%, PR-P recovery (2.57% was much lower even when mixed together in the ratio of 80% TSP: 20% PR. There was no difference in PR-P utilization by the corn plants with increasing P rates in the mixture (1:1 proportion. Therefore, PR-P availability is affected by the proportions of the mixtures with water soluble P, but not by P rates.A disponibilidade de fósforo do fosfato natural de Patos de Minas (FN pode ser melhorada se aplicado junto com uma fonte de P solúvel em água. O objetivo desse estudo foi usar o 32P como traçador para quantificar o efeito das doses e das proporções das misturas de superfosfato triplo (SFT com FN no aumento da disponibilidade de P do FN. Dois experimentos foram desenvolvidos em casa-de-vegetação com plantas de milho (Zea mays L. como cultura teste. No primeiro experimento as fontes de fósforo, na dose de 90 mg kg-1

  2. Study of the radiation scattered and produced by concrete shielding of radiotherapy rooms and its effects on equivalent doses in patients' organs

    International Nuclear Information System (INIS)

    Braga, K.L.; Rebello, W.F.; Andrade, E.R.; Gavazza, S.; Medeiros, M.P.C.; Mendes, R.M.S.; Gomes, R.G.; Silva, M.G.; Thalhofer, J.L.; Silva, A.X.; Santos, R.F.G.

    2015-01-01

    Within a radiotherapy room, in addition to the primary beam, there is also secondary radiation due to the leakage of the accelerator head and the radiation scattering from room objects, patient and even the room's shielding itself, which is projected to protect external individuals disregarding its effects on the patient. This work aims to study the effect of concrete shielding wall over the patient, taking into account its contribution on equivalent doses. The MCNPX code was used to model the linear accelerator Varian 2100/2300 C/D operating at 18MeV, with MAX phantom representing the patient undergoing radiotherapy treatment for prostate cancer following Brazilian Institute of Cancer four-fields radiation application protocol (0°, 90°, 180° and 270°). Firstly, the treatment was patterned within a standard radiotherapy room, calculating the equivalent doses on patient's organs individually. In a second step, this treatment was modeled withdrawing the walls, floor and ceiling from the radiotherapy room, and then the equivalent doses calculated again. Comparing these results, it was found that the concrete has an average shielding contribution of around 20% in the equivalent dose on the patient's organs. (author)

  3. The choice of individual dose criterion at which to restrict agricultural produce following an unplanned release of radioactive material to atmosphere

    CERN Document Server

    Dionian, J

    1985-01-01

    In the event of an accidental release of radioactive material to atmosphere, the introduction of emergency countermeasures will be based on the need to limit the risk to individuals. However, it has been suggested that a form of cost-benefit analysis may be used as an input to decisions on the withdrawal of countermeasures, although it is recognised that these decisions may be influenced by factors other than those directly related to radiological protection. In this study, a method based on cost-benefit analysis is illustrated for assessing the optimum level of individual dose at which restrictions on agricultural production may be considered. This requires monetary values to be assigned to both the lost food production and to the health detriment, expressed as the collective effective dose equivalent commitment. It has been assumed in this analysis that food-supply restrictions are both introduced and withdrawn at the same projected level of annual individual dose. The effect on the optimum dose level of th...

  4. Investigation into the Manufacture and Properties of Inhalable High-Dose Dry Powders Produced by Comilling API and Lactose with Magnesium Stearate.

    Science.gov (United States)

    Lau, Michael; Young, Paul M; Traini, Daniela

    2017-08-01

    The aim of the study was to understand the impact of different concentrations of the additive material, magnesium stearate (MGST), and the active pharmaceutical ingredient (API), respectively, on the physicochemical properties and aerosol performance of comilled formulations for high-dose delivery. Initially, blends of API/lactose with different concentrations of MGST (1-7.5% w/w) were prepared and comilled by the jet-mill apparatus. The optimal concentration of MGST in comilled formulations was investigated, specifically for agglomerate structure and strength, particle size, uniformity of content, surface coverage, and aerosol performance. Secondly, comilled formulations with different API (1-40% w/w) concentrations were prepared and similarly analyzed. Comilled 5% MGST (w/w) formulation resulted in a significant improvement in in vitro aerosol performance due to the reduction in agglomerate size and strength compared to the formulation comilled without MGST. Higher concentrations of MGST (7.5% w/w) led to reduction in aerosol performance likely due to excessive surface coverage of the micronized particles by MGST, which led to failure in uniformity of content and an increase in agglomerate strength and size. Generally, comilled formulations with higher concentrations of API increased the agglomerate strength and size, which subsequently caused a reduction in aerosol performance. High-dose delivery was achieved at API concentration of >20% (w/w). The study provided a platform for the investigation of aerosol performance and physicochemical properties of other API and additive materials in comilled formulations for the emerging field of high-dose delivery by dry powder inhalation.

  5. Golden Ratio

    Indian Academy of Sciences (India)

    of mathematical biology. Our attraction to another body increases if the body is sym- metrical and in proportion. If a face or a structure is in pro- ... his practice of oral and maxillofacial surgery, and he developed a mask using the concept of golden ratio. The mask is called the. Marquardt beauty mask (Figure 1) [1]. Keywords.

  6. Oxygen enhancement ratio for negative pi mesons

    International Nuclear Information System (INIS)

    Hall, E.J.; Astor, M.

    1979-01-01

    Experiments were performed at the Los Alamos Meson Physics Facility (LAMPF) to determine the oxygen enhancement ratio (OER) for the clinically used beam of negative pi mesons. V79 Chinese hamster cells, cultured in vitro, were used as the biological test system; hypoxia was produced by metabolic depletion as a result of sealing 2 million cells in 1 ml glass ampules. The Bragg peak of the pion depth dose curve was spread out to cover 10 cm by using a dynamic range shifter. Cells were irradiated at the center of the spead out Bragg peak, where the dose/rate was 0.1 Gy/min over a 6 x 6 cm field. The OER obtained was 2.2, compared with 3.8 obtained for γ rays under the same conditions

  7. An autopsied case of human chorionic gonadotropin (HCG)-producing lung cancer accompanied by bilateral radiation pneumonitis due to small doses of irradiation

    International Nuclear Information System (INIS)

    Tano, Yoshihiko; Adachi, Michifumi; Kimura, Makoto; Matsushima, Toshiharu; Torii, Takashi

    1990-01-01

    An autopsied case of human chorionic gonadotropin (HCG)-producing lung cancer accompanied by bilateral radiation pneumonitis is reported. A 68 year-old male was admitted to our hospital because of an abnormal shadow in his chest x-ray. Lung cancer was diagnosed and treated with radiotherapy. The radiotherapy (1,200 cGy) was discontinued, however because his general condition deteriorated. Chest x-rays then showed a pneumonia-like shadow in the projected field of irradiation. The same shadow was observed in the contralateral lung field one month later. Gynecomastia and an elevated level of serum HCG were noticed during hospitalization. The patient died and an autopsy was performed. Histopathological examination upon autopsy confirmed a large cell carcinoma of the lung which stained positively for HCG with an immunoenzyme labelling technique using the PAP method. Marked fibrosis and thickening of the alveolar septae were histologically demonstrated in the projected field of irradiation and the contralateral field where chest x-rays showed the pneumonia-like shadow. (author)

  8. An autopsied case of human chorionic gonadotropin (HCG)-producing lung cancer accompanied by bilateral radiation pneumonitis due to small doses of irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tano, Yoshihiko; Adachi, Michifumi; Kimura, Makoto; Matsushima, Toshiharu; Torii, Takashi (Kawasaki Medical School, Kawasaki Hospital, Okayama (Japan))

    1990-07-01

    An autopsied case of human chorionic gonadotropin (HCG)-producing lung cancer accompanied by bilateral radiation pneumonitis is reported. A 68 year-old male was admitted to our hospital because of an abnormal shadow in his chest x-ray. Lung cancer was diagnosed and treated with radiotherapy. The radiotherapy (1,200 cGy) was discontinued, however because his general condition deteriorated. Chest x-rays then showed a pneumonia-like shadow in the projected field of irradiation. The same shadow was observed in the contralateral lung field one month later. Gynecomastia and an elevated level of serum HCG were noticed during hospitalization. The patient died and an autopsy was performed. Histopathological examination upon autopsy confirmed a large cell carcinoma of the lung which stained positively for HCG with an immunoenzyme labelling technique using the PAP method. Marked fibrosis and thickening of the alveolar septae were histologically demonstrated in the projected field of irradiation and the contralateral field where chest x-rays showed the pneumonia-like shadow. (author).

  9. Dose and dose rate monitor

    International Nuclear Information System (INIS)

    Novakova, O.; Ryba, J.; Slezak, V.; Svobodova, B.; Viererbl, L.

    1984-10-01

    The methods are discussea of measuring dose rate or dose using a scintillation counte. A plastic scintillator based on polystyrene with PBD and POPOP activators and coated with ZnS(Ag) was chosen for the projected monitor. The scintillators were cylindrical and spherical in shape and of different sizes; black polypropylene tubes were chosen as the best case for the probs. For the counter with different plastic scintillators, the statistical error 2σ for natural background was determined. For determining the suitable thickness of the ZnS(Ag) layer the energy dependence of the counter was measured. Radioisotopes 137 Cs, 241 Am and 109 Cd were chosen as radiation sources. The best suited ZnS(Ag) thickness was found to be 0.5 μm. Experiments were carried out to determine the directional dependence of the detector response and the signal to noise ratio. The temperature dependence of the detector response and its compensation were studied, as were the time stability and fatigue manifestations of the photomultiplier. The design of a laboratory prototype of a dose rate and dose monitor is described. Block diagrams are given of the various functional parts of the instrument. The designed instrument is easiiy portable, battery powered, measures dose rates from natural background in the range of five orders, i.e., 10 -2 to 10 3 nGy/s, and allows to determine a dose of up to 10 mGy. Accouracy of measurement in the energy range of 50 keV to 1 MeV is better than +-20%. (E.S.)

  10. Treatment with rituximab, dexamethasone, high-dose cytarabine, and oxaliplatin (R-DHAOx) produces a strong long-term antitumor effect in previously treated patients with follicular non-Hodgkin's lymphoma.

    Science.gov (United States)

    Machover, D; Delmas-Marsalet, B; Misra, S C; Ulusakarya, A; Gumus, Y; Frénoy, N; Guettier, C; Saffroy, R; Innominato, P; Almohamad, W; Brahimi, N; Haydar, M; Goldschmidt, E

    2010-02-01

    We explored the addition of rituximab to high-dose cytarabine (ara-C), oxaliplatin (L-OHP), and dexamethasone [R-DHAOx], in resistant and relapsed patients with CD20-positive follicular non-Hodgkin's lymphoma. Twenty-two patients were included; they were treated previously with one to five chemotherapy regimens, including 13 patients who had also received rituximab. R-DHAOx consisted of rituximab, 375mg/m(2), day 1; dexamethasone, 40mg/d, days one to four; L-OHP, 130mg/m(2), day 1; and ara-C, 2000mg/m(2) every 12 h, day 2. Courses were repeated every 21 days for eight courses. Twenty-one patients (95%) achieved a complete response and one had a partial response. Responses were obtained in patients with and without resistance to prior treatment, either alone or combined with rituximab. The median follow-up time was 58.3 months (range, 8.7-92.6 months). Progression-free survival reached a plateau at 84% at 38.2 months. Only two of the 21 complete responders have relapsed. Tumor molecular markers disappeared in all 10 complete responders whose markers were found before treatment. Peripheral neuropathy related to the cumulative dose of L-OHP, and myelosuppression were the most prominent toxic effects. R-DHAOx is highly active for salvage treatment of patients with follicular non-Hodgkin's lymphoma, and it produces long-term antitumor efficacy. 2009 Elsevier Masson SAS. All rights reserved.

  11. Dose sculpting with generalized equivalent uniform dose

    International Nuclear Information System (INIS)

    Wu Qiuwen; Djajaputra, David; Liu, Helen H.; Dong Lei; Mohan, Radhe; Wu, Yan

    2005-01-01

    With intensity-modulated radiotherapy (IMRT), a variety of user-defined dose distribution can be produced using inverse planning. The generalized equivalent uniform dose (gEUD) has been used in IMRT optimization as an alternative objective function to the conventional dose-volume-based criteria. The purpose of this study was to investigate the effectiveness of gEUD optimization to fine tune the dose distributions of IMRT plans. We analyzed the effect of gEUD-based optimization parameters on plan quality. The objective was to determine whether dose distribution to selected structures could be improved using gEUD optimization without adversely altering the doses delivered to other structures, as in sculpting. We hypothesized that by carefully defining gEUD parameters (EUD 0 and n) based on the current dose distributions, the optimization system could be instructed to search for alternative solutions in the neighborhood, and we could maintain the dose distributions for structures already satisfactory and improve dose for structures that need enhancement. We started with an already acceptable IMRT plan optimized with any objective function. The dose distribution was analyzed first. For structures that dose should not be changed, a higher value of n was used and EUD 0 was set slightly higher/lower than the EUD value at the current dose distribution for critical structures/targets. For structures that needed improvement in dose, a higher to medium value of n was used, and EUD 0 was set to the EUD value or slightly lower/higher for the critical structure/target at the current dose distribution. We evaluated this method in one clinical case each of head and neck, lung and prostate cancer. Dose volume histograms, isodose distributions, and relevant tolerance doses for critical structures were used for the assessment. We found that by adjusting gEUD optimization parameters, the dose distribution could be improved with only a few iterations. A larger value of n could lead to

  12. The abbreviated impactor measurement (AIM) concept: part II--Influence of evaporation of a volatile component-evaluation with a "droplet-producing" pressurized metered dose inhaler (pMDI)-based formulation containing ethanol as cosolvent.

    Science.gov (United States)

    Mitchell, J P; Nagel, M W; Avvakoumova, V; MacKay, H; Ali, R

    2009-01-01

    The abbreviated impactor measurement (AIM) concept is a potential solution to the labor-intensive full-resolution cascade impactor (CI) methodology for inhaler aerosol aerodynamic particle size measurement. In this validation study, the effect of increasing the internal dead volume on determined mass fractions relating to aerodynamic particle size was explored with two abbreviated impactors both based on the Andersen nonviable cascade impactor (ACI) operating principle (Copley fast screening Andersen impactor [C-FSA] and Trudell fast screening Andersen impactor [T-FSA]). A pressurized metered dose inhaler-delivered aerosol producing liquid ethanol droplets after propellant evaporation was chosen to characterize these systems. Measures of extrafine, fine, and coarse particle mass fractions from the abbreviated systems were compared with corresponding data obtained by a full-resolution ACI. The use of liquid ethanol-sensitive filter paper provided insight by rendering locations visible where partly evaporated droplets were still present when the "droplet-producing" aerosol was sampled. Extrafine particle fractions based on impactor-sized mass were near equivalent in the range 48.6% to 54%, comparing either abbreviated system with the benchmark ACI-measured data. The fine particle fraction of the impactor-sized mass determined by the T-FSA (94.4 +/- 1.7%) was greater than using the C-FSA (90.5 +/- 1.4%) and almost identical with the ACI-measured value (95.3 +/- 0.4%). The improved agreement between T-FSA and ACI is likely the result of increasing the dead space between the entry to the induction port and the uppermost impaction stage, compared with that for the C-FSA. This dead space is needed to provide comparable conditions for ethanol evaporation in the uppermost parts of these impactors.

  13. Large Aspect Ratio Tokamak Study

    International Nuclear Information System (INIS)

    Reid, R.L.; Holmes, J.A.; Houlberg, W.A.; Peng, Y.K.M.; Strickler, D.J.; Brown, T.G.; Wiseman, G.W.

    1980-06-01

    The Large Aspect Ratio Tokamak Study (LARTS) at Oak Ridge National Laboratory (ORNL) investigated the potential for producing a viable longburn tokamak reactor by enhancing the volt-second capability of the ohmic heating transformer through the use of high aspect ratio designs. The plasma physics, engineering, and economic implications of high aspect ratio tokamaks were assessed in the context of extended burn operation. Using a one-dimensional transport code plasma startup and burn parameters were addressed. The pulsed electrical power requirements for the poloidal field system, which have a major impact on reactor economics, were minimized by optimizing the startup and shutdown portions of the tokamak cycle. A representative large aspect ratio tokamak with an aspect ratio of 8 was found to achieve a burn time of 3.5 h at capital cost only approx. 25% greater than that of a moderate aspect ratio design tokamak

  14. Holes at High Blowing Ratios

    Directory of Open Access Journals (Sweden)

    Phillip M. Ligrani

    1996-01-01

    Full Text Available Experimental results are presented which describe the development and structure of flow downstream of a single row of holes with compound angle orientations producing film cooling at high blowing ratios. This film cooling configuration is important because similar arrangements are frequently employed on the first stage of rotating blades of operating gas turbine engines. With this configuration, holes are spaced 6d apart in the spanwise direction, with inclination angles of 24 degrees, and angles of orientation of 50.5 degrees. Blowing ratios range from 1.5 to 4.0 and the ratio of injectant to freestream density is near 1.0. Results show that spanwise averaged adiabatic effectiveness, spanwise-averaged iso-energetic Stanton number ratios, surveys of streamwise mean velocity, and surveys of injectant distributions change by important amounts as the blowing ratio increases. This is due to injectant lift-off from the test surface just downstream of the holes.

  15. Tau hadronic branching ratios

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, L M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    From 64492 selected \\tau-pair events, produced at the Z^0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. Special emphasis is given to the reconstruction of photons and \\pi^0's, and the removal of fake photons. A detailed study of the systematics entering the \\pi^0 reconstruction is also given. A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. Most measurements are more precise than the present world average. The new level of precision reached allows a stringent test of \\tau-\\mu universality in hadronic decays, g_\\tau/g_\\mu \\ = \\ 1.0013 \\ \\pm \\ 0.0095, and the first measurement of the vector and axial-vector contributions to the non-strange hadronic \\tau decay width: R_{\\tau ,V} \\ = \\ 1.788 \\ \\pm \\ 0.025 and R_{\\tau ,A} \\ = \\ 1.694 \\ \\pm \\ 0.027. The ratio (R_{\\tau ,V} - R_{\\tau ,A}) / (R_{\\tau ,V} + R_{\\tau ,A}), equal to (2.7 \\pm 1.3) \\ \\%, is a measure of the importance of Q...

  16. Ionization chamber for high dose measurements

    International Nuclear Information System (INIS)

    Rodrigues Junior, Ary de Araujo

    2005-01-01

    Industrial gamma irradiators facilities are designed for processing large amounts of products, which are exposed to large doses of gamma radiation. The irradiation, in industrial scale, is usually carried out in a dynamic form, where the products go through a 60 Co gamma source with activity of TBq to P Bq (k Ci to MCi). The dose is estimated as being directly proportional to the time that the products spend to go through the source. However, in some situations, mainly for research purposes or for validation of customer process following the ISO 11137 requirements, it is required to irradiate small samples in a static position with fractional deliver doses. The samples are put inside the irradiation room at a fixed distance from the source and the dose is usually determined using dosimeters. The dose is only known after the irradiation, by reading the dosimeter. Nevertheless, in the industrial irradiators, usually different kinds of products with different densities go through between the source and the static position samples. So, the dose rate varies in function of the product density. A suitable methodology would be to monitor the samples dose in real time, measuring the dose on line with a radiation detector, which would improve the dose accuracy and avoid the overdose. A cylindrical ionization chamber of 0.9 cm 3 has been developed for high-doses real-time monitoring, during the sample irradiation at a static position in a 60 Co gamma industrial plant. Nitrogen and argon gas at pressure of 10 exp 5 Pa (1 bar) was utilized to fill the ionization chamber, for which an appropriate configuration was determined to be used as a detector for high-dose measurements. To transmit the signal generated in the ionization chamber to the associated electronic and processing unit, a 20 m mineral insulated cable was welded to the ionization chamber. The signal to noise ratio produced by the detector was about 100. The dosimeter system was tested at a category I gamma

  17. The relative biological effectiveness of out-of-field dose

    Science.gov (United States)

    Balderson, Michael; Koger, Brandon; Kirkby, Charles

    2016-01-01

    Purpose: using simulations and models derived from existing literature, this work investigates relative biological effectiveness (RBE) for out-of-field radiation and attempts to quantify the relative magnitudes of different contributing phenomena (spectral, bystander, and low dose hypersensitivity effects). Specific attention is paid to external beam radiotherapy treatments for prostate cancer. Materials and methods: using different biological models that account for spectral, bystander, and low dose hypersensitivity effects, the RBE was calculated for different points moving radially out from isocentre for a typical single arc VMAT prostate case. The RBE was found by taking the ratio of the equivalent dose with the physical dose. Equivalent doses were calculated by determining what physical dose would be necessary to produce the same overall biological effect as that predicted using the different biological models. Results: spectral effects changed the RBE out-of-field less than 2%, whereas response models incorporating low dose hypersensitivity and bystander effects resulted in a much more profound change of the RBE for out-of-field doses. The bystander effect had the largest RBE for points located just outside the edge of the primary radiation beam in the cranial caudal (z-direction) compared to low dose hypersensitivity and spectral effects. In the coplanar direction, bystander effect played the largest role in enhancing the RBE for points up to 8.75 cm from isocentre. Conclusions: spectral, bystander, and low dose hypersensitivity effects can all increase the RBE for out-of-field radiation doses. In most cases, bystander effects seem to play the largest role followed by low dose hypersensitivity. Spectral effects were unlikely to be of any clinical significance. Bystander, low dose hypersensitivity, and spectral effect increased the RBE much more in the cranial caudal direction (z-direction) compared with the coplanar directions.

  18. Dose reduction in evacuation proctography

    International Nuclear Information System (INIS)

    Hare, C.; Halligan, S.; Bartram, C.I.; Gupta, R.; Walker, A.E.; Renfrew, I.

    2001-01-01

    The goal of this study was to reduce the patient radiation dose from evacuation proctography. Ninety-eight consecutive adult patients referred for proctography to investigate difficult rectal evacuation were studied using a digital imaging system with either a standard digital program for barium examinations, a reduced dose digital program (both with and without additional copper filtration), or Video fluoroscopy. Dose-area products were recorded for each examination and the groups were compared. All four protocols produced technically acceptable examinations. The low-dose program with copper filtration (median dose 382 cGy cm 2 ) and Video fluoroscopy (median dose 705 cGy cm 2 ) were associated with significantly less dose than other groups (p < 0.0001). Patient dose during evacuation proctography can be reduced significantly without compromising the diagnostic quality of the examination. A digital program with added copper filtration conveyed the lowest dose. (orig.)

  19. High aspect ratio template and method for producing same

    Science.gov (United States)

    Sakamoto, Jeff S. (Inventor); Weiss, James R. (Inventor); Fleurial, Jean-Pierre (Inventor); Kisor, Adam (Inventor); Tuszynski, Mark (Inventor); Stokols, Shula (Inventor); Holt, Todd Edward (Inventor); Welker, David James (Inventor); Breckon, Christopher David (Inventor)

    2010-01-01

    Millimeter to nano-scale structures manufactured using a multi-component polymer fiber matrix are disclosed. The use of dissimilar polymers allows the selective dissolution of the polymers at various stages of the manufacturing process. In one application, biocompatible matrixes may be formed with long pore length and small pore size. The manufacturing process begins with a first polymer fiber arranged in a matrix formed by a second polymer fiber. End caps may be attached to provide structural support and the polymer fiber matrix selectively dissolved away leaving only the long polymer fibers. These may be exposed to another product, such as a biocompatible gel to form a biocompatible matrix. The polymer fibers may then be selectively dissolved leaving only a biocompatible gel scaffold with the pores formed by the dissolved polymer fibers.

  20. Dose responses of in vivo- and in vitro-produced strains of gypsy moth (Lepidoptera: Lymantriidae) nucleopolyhedrovirus (LdMNPV) applied with and without the virus enhancer Blankophor BBH

    Science.gov (United States)

    John D. Podgwaite; James M. Slavicek; Kevin W. Thorpe; Ralph E. Webb; Roger W. Fuester; Vincent D' Amico; Randel A. Peiffer; Michael A. Valenti

    2013-01-01

    The gypsy moth, Lymantria dispar L., nucleopolyhedrovirus (LdMNPV) product Gypchek is a microbial pesticide produced by the USDA Forest Service. Gypchek is a mixture of LdMNPV genotypes produced in vivo. Commercial interests prefer to develop a stable, high-potency genotype that can be produced at low cost, preferably in vitro. We sprayed 2 LdMNPV...

  1. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  2. Effects of gamma radiation on development, sterility, fecundity, and sex ratio of Dermanyssus gallinae (DeGeer) (Acari: Dermanyssidae)

    International Nuclear Information System (INIS)

    Entrekin, D.L.; Oliver, J.H. Jr.; Pound, J.M.

    1987-01-01

    Protonymphal Dermanyssus gallinae were irradiated with 0.50, 0.75, 1.0, 3.0, and 6.0 krad of gamma radiation and subsequently monitored regarding their developmental, feeding, and mating success. Also, sex ratios of adults treated as protonymphs were recorded as were sex ratios of embryos and F1 adults produced by these adults. Doses up to 1.0 krad did not prevent development of treated protonymphs to the adult stage or stop mating. Three krad reduced the number of treated protonymphs attaining adulthood and 6.0-krad treatment prevented all mites from developing to the adult stage. Egg (embryo) production was normal for mites treated with 0.50 krad, but significantly curtailed by doses of 0.75 krad and greater. Radiation doses used in this study did not appear to affect the normal variable sex ratios observed in untreated mites

  3. Substratos na aclimatização de Pfaffia glomerata (Spreng Pedersen produzida in vitro sob diferentes doses de sacarose Substrates in the acclimatization of Pfaffia glomerata (Spreng. Pedersen produced in vitro under different levels of sucrose

    Directory of Open Access Journals (Sweden)

    Etiane Caldeira Skrebsky

    2006-10-01

    Full Text Available Este trabalho teve como objetivo selecionar substratos para a aclimatização de plântulas de Pfaffia glomerata produzidas in vitro sob diferentes concentrações de sacarose. Os tratamentos consistiram de uma combinação bifatorial (5x3 entre cinco doses de sacarose (15, 30, 45, 60 e 75g L-1, presentes no meio de cultura in vitro, e três substratos [Plantmax® Hortaliças, Plantmax® + Solo (1:1 v/v e Vermiculita (granulometria média + Solo (ARGISSOLO VERMELHO Distrófico arênico (1:1 v/v] utilizados na aclimatização ex vitro. Foram realizadas determinações das características físicas e químicas dos substratos, bem como avaliações do crescimento e da sobrevivência das plantas tanto durante o cultivo in vitro como no ex vitro. Plantas provenientes do cultivo in vitro na presença de 45 a 60g L-1 de sacarose apresentaram melhor aclimatização ex vitro. As combinações dos substratos Vermiculita + solo (1:1 v/v e Plantmax® + solo (1:1 v/v proporcionaram maior crescimento às plantas durante a última fase de aclimatização (cultivo sob sombrite, provavelmente devido a possuírem maior porosidade total. Entretanto, o uso isolado de Plantmax® aumentou a sobrevivência das plantas cultivadas a campo, fato relacionado a esse substrato possuir os maiores valores de capacidade de retenção de água, de água facilmente disponível e de água disponível.This work was aimed at selecting substrates on the ex vitro acclimatization of Pfaffia glomerata produced in vitro under different sucrose levels. The treatments consisted of a bifactorial combination (5x3 between five sucrose levels (15, 30, 45, 60, and 75g L-1, present in the in vitro culture, and three substrates [Plantmax®; Plantmax® + soil (1:1 v/v, and vermiculite (middle size + soil (Paleudalf (1:1 v/v] used in the ex vitro acclimatization steps. Physical and chemical evaluations of the substrates were carried out as well as evaluations of plant growth and survival for both

  4. Analysis of the NAEG model of transuranic radionuclide transport and dose

    International Nuclear Information System (INIS)

    Kercher, J.R.; Anspaugh, L.R.

    1984-11-01

    We analyze the model for estimating the dose from 239 Pu developed for the Nevada Applied Ecology Group (NAEG) by using sensitivity analysis and uncertainty analysis. Sensitivity analysis results suggest that the air pathway is the critical pathway for the organs receiving the highest dose. Soil concentration and the factors controlling air concentration are the most important parameters. The only organ whose dose is sensitive to parameters in the ingestion pathway is the GI tract. The air pathway accounts for 100% of the dose to lung, upper respiratory tract, and thoracic lymph nodes; and 95% of its dose via ingestion. Leafy vegetable ingestion accounts for 70% of the dose from the ingestion pathway regardless of organ, peeled vegetables 20%; accidental soil ingestion 5%; ingestion of beef liver 4%; beef muscle 1%. Only a handful of model parameters control the dose for any one organ. The number of important parameters is usually less than 10. Uncertainty analysis indicates that choosing a uniform distribution for the input parameters produces a lognormal distribution of the dose. The ratio of the square root of the variance to the mean is three times greater for the doses than it is for the individual parameters. As found by the sensitivity analysis, the uncertainty analysis suggests that only a few parameters control the dose for each organ. All organs have similar distributions and variance to mean ratios except for the lymph modes. 16 references, 9 figures, 13 tables

  5. Analysis of the NAEG model of transuranic radionuclide transport and dose

    International Nuclear Information System (INIS)

    Kercher, J.R.; Anspaugh, L.R.

    1984-01-01

    We analyze the model for estimating the dose FR-om /sup 239/Pu developed for the Nevada Applied Ecology Group (NAEG) by using sensitivity analysis and uncertainty analysis. Sensitivity analysis results suggest that the air pathway is the critical pathway for the organs receiving the highest dose. Soil concentration and the factors controlling air concentration are the most important parameters. The only organ whose dose is sensitive to parameters in the ingestion pathway is the GI tract. The air pathway accounts for 100% of the dose to lung, upper respiratory tract, and thoracic lymph nodes; and 95% of its dose via ingestion. Leafy vegetable ingestion accounts for 70% of the dose FR-om the ingestion pathway regardless of organ, peeled vegetables 20%; accidental soil ingestion 5%; ingestion of beef liver 4%; beef muscle 1%. Only a handful of model parameters control the dose for any one organ. The number of important parameters is usually less than 10. Uncertainty analysis indicates that choosing a uniform distribution for the input parameters produces a lognormal distribution of the dose. The ratio of the square root of the variance to the mean is three times greater for the doses than it is for the individual parameters. As found by the sensitivity analysis, the uncertainty analysis suggests that only a few parameters control the dose for each organ. All organs have similar distributions and variance to mean ratios except for the lymph modes. 16 references, 9 figures, 13 tables

  6. Financial Key Ratios

    OpenAIRE

    Tănase Alin-Eliodor

    2014-01-01

    This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.

  7. Controllable dose

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Anaya M, R.A.

    2004-01-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  8. Doses produced in Spain as a results of radiation-based diagnosis (Projects Dopoes{sub D}omnes); Dosis producidas en Espana como consecuencia del diagnostico con radiaciones (Proyectos Dopoes{sub D}omnes)

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Cruces, R.; Ramirez Vera, M. L.; Alvarez Garcia, C.; Ferrer, N.

    2016-08-01

    The number of medical examinations and procedures that use ionizing radiation have continuously increased in recently years. More than 90% of human-generated exposures to ionizing radiation are from medical uses and the collective dose due to patient exposures is 200 times greater than the occupational dose of exposed workers. At the same time, the emergence of new technologies, the increased use of Computerized Tomography (CT)-even for pediatric patients- the development of digital radiography, interventional radiology and the new technologies in nuclear medicine with the use of hybrid PET/CT and SPECT/CT equipment have all contributed as well to an increase in the doses received by patients. This poses a challenge to the regulatory authorities in the field of radiological protection, the goal of which is to makes sure that the risks to patients are as low as possible compared to the benefits yielded by the use of ionizing radiation for medical purposes, in accordance with ALARA criteria. (Author)

  9. Dose due to {sup 40}K

    Energy Technology Data Exchange (ETDEWEB)

    Escareno J, E.; Vega C, H. R., E-mail: edmundoej@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2011-10-15

    The dose due to {sup 40}K has been estimated. Potassium is one of the most abundant elements in nature, being approximately 2% of the Earth's crust. Potassium has three isotopes {sup 39}K, {sup 40}K and {sup 41}K, two are stable while {sup 40}K is radioactive with a half life of 1.2x10{sup 9} years; there is 0.0117% {sup 40}K-to-K ratio. Potassium plays an important role in plants, animals and humans growth and reproduction. Due to the fact that K is an essential element for humans, {sup 40}K is the most abundant radioisotope in human body. In order to keep good health conditions K must be intake at daily basis trough food and beverages, however when K in ingested above the requirements produce adverse health effects in persons with renal, cardiac and hypertension problems or suffering diabetes. In 89.3% {sup 40}K decays to {sup 40}C through {beta}-decay, in 10.3% decays through electronic capture and emitting 1.46 MeV {gamma}-ray. K is abundant in soil, construction materials, sand thus {gamma}-rays produced during {sup 40}K decay contribute to external dose. For K in the body practically all {sup 40}K decaying energy is absorbed by the body; thus {sup 40}K contributes to total dose in humans and it is important to evaluate its contribution. In this work a set of {sup 40}K sources were prepared using different amounts of KCl salt, a {gamma}-ray spectrometer with a NaI(Tl) was characterized to standardized the sources in order to evaluate the dose due to {sup 40}K. Using thermoluminescent dosemeters the dose due to {sup 40}K was measured and related to the amount of {sup 40}K {gamma}-ray activity. (Author)

  10. Radiotherapy dose compensation for lung patients

    International Nuclear Information System (INIS)

    Piyaratna, N.; Arnold, A.; Metcalfe, P.

    1999-01-01

    The purpose of the present paper is to provide a more homogeneous dose distribution in the target volume from compensated anterior and posterior fields while the healthy lung is spared by de-weighting the lateral fields. A compensation computation which used linear iterations to compute the most homogeneous dose distribution across the target volume was applied to produce optimum compensator designs. The equivalent tissue-air ratio (E-TAR) inhomogeneity correction was applied for the computations using a GE target series 11 planning computer. The compensators designed were tested for accuracy in a modified water/lung phantom using a scanning diode and an anthropomorphic phantom using thermoluminescent dosimeters. A comparison has been made between the compensated and uncompensated plans for the first nine patients who we have treated with this technique. The dose profiles produced by the computation agreed with the prediction of the computed isodose plans to within ± 2% at the target depth. The thermoluminescent dosimeter (TLD)-measured results in the anthropomorphic phantom agreed with the planning computer within ± 3%. A comparison of nine compensated plans of radiotherapy patients for large-volume targets in the lung region showed a maximum variation in the target to be 19% uncompensated versus 10% compensated. By providing compensated treatment fields from anterior and posterior treatment portals, a homogeneous dose that conforms well to the target volume is provided. As an added bonus, this enables the lateral lung fields to be significantly de-weighted and the healthy lung is spared considerable dose. Copyright (1999) Blackwell Science Pty Ltd

  11. A mutant with riboflavin productivity obtained from non-riboflavin-producing ashbya gossypii by γ-induction

    International Nuclear Information System (INIS)

    Yang Suhong; Ge Zhongliang

    1993-01-01

    60 Co γ-ray was used to irradiate Ashbya gossypii, which does not produce riboflavin originally, and mutants were obtained with colonial colour changing from white into yellow. Mutant ratio was high at the absorption dose of 90 Gy. Results of reverse phase-HPLC, high performance-TLC and fluoroscopic analysis proved that riboflavin is produced by the mutant fermentation. The mutant remained after generations of culture, indicating that the induced new properties are stably inheritable

  12. Study of the radiation scattered and produced by concrete shielding of radiotherapy rooms and its effects on equivalent doses in patients' organs; Estudo da radiacao espalhada e produzida pela blindagem de concreto de salas de radioterapia e seus efeitos sobre doses equivalentes nos orgaos dos pacientes

    Energy Technology Data Exchange (ETDEWEB)

    Braga, K.L.; Rebello, W.F.; Andrade, E.R.; Gavazza, S.; Medeiros, M.P.C.; Mendes, R.M.S.; Gomes, R.G.; Silva, M.G., E-mail: kelmo.lins@gmail.com, E-mail: rebello@ime.eb.br, E-mail: fisica.dna@gmail.com, E-mail: sergiogavazza@yahoo.com, E-mail: eng.cavaliere@gmail.com, E-mail: raphaelmsm@gmail.com, E-mail: ggrprojetos@gmail.com, E-mail: maglosilva15@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear; Thalhofer, J.L.; Silva, A.X., E-mail: jardellt@yahoo.com.br, E-mail: ademir@con.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Energia Nuclear; Santos, R.F.G., E-mail: raphaelfgsantos@gmail.com [Centro Universitario Anhanguera, Niteroi, RJ (Brazil). Departamento de Engenharia

    2015-07-01

    Within a radiotherapy room, in addition to the primary beam, there is also secondary radiation due to the leakage of the accelerator head and the radiation scattering from room objects, patient and even the room's shielding itself, which is projected to protect external individuals disregarding its effects on the patient. This work aims to study the effect of concrete shielding wall over the patient, taking into account its contribution on equivalent doses. The MCNPX code was used to model the linear accelerator Varian 2100/2300 C/D operating at 18MeV, with MAX phantom representing the patient undergoing radiotherapy treatment for prostate cancer following Brazilian Institute of Cancer four-fields radiation application protocol (0°, 90°, 180° and 270°). Firstly, the treatment was patterned within a standard radiotherapy room, calculating the equivalent doses on patient's organs individually. In a second step, this treatment was modeled withdrawing the walls, floor and ceiling from the radiotherapy room, and then the equivalent doses calculated again. Comparing these results, it was found that the concrete has an average shielding contribution of around 20% in the equivalent dose on the patient's organs. (author)

  13. Prediction of midline dose from entrance ad exit dose using OSLD measurements for total irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Heon; Park, Jong Min; Park, So Yeon; Chun, Min Soo; Han, Ji Hye; Cho, Jin Dong; Kim, Jung In [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-06-15

    This study aims to predict the midline dose based on the entrance and exit doses from optically stimulated luminescence detector (OSLD) measurements for total body irradiation (TBI). For TBI treatment, beam data sets were measured for 6 MV and 15 MV beams. To evaluate the tissue lateral effect of various thicknesses, the midline dose and peak dose were measured using a solid water phantom (SWP) and ion chamber. The entrance and exit doses were measured using OSLDs. OSLDs were attached onto the central beam axis at the entrance and exit surfaces of the phantom. The predicted midline dose was evaluated as the sum of the entrance and exit doses by OSLD measurement. The ratio of the entrance dose to the exit dose was evaluated at various thicknesses. The ratio of the peak dose to the midline dose was 1.12 for a 30 cm thick SWP at both energies. When the patient thickness is greater than 30 cm, the 15 MV should be used to ensure dose homogeneity. The ratio of the entrance dose to the exit dose was less than 1.0 for thicknesses of less than 30 cm and 40 cm at 6 MV and 15 MV, respectively. Therefore, the predicted midline dose can be underestimated for thinner body. At 15 MV, the ratios were approximately 1.06 for a thickness of 50 cm. In cases where adult patients are treated with the 15 MV photon beam, it is possible for the predicted midline dose to be overestimated for parts of the body with a thickness of 50 cm or greater. The predicted midline dose and OSLD-measured midline dose depend on the phantom thickness. For in-vivo dosimetry of TBI, the measurement dose should be corrected in order to accurately predict the midline dose.

  14. Difference and ratio plots

    DEFF Research Database (Denmark)

    Svendsen, Anders Jørgen; Holmskov, U; Bro, Peter

    1995-01-01

    hitherto unnoted differences between controls and patients with either rheumatoid arthritis or systemic lupus erythematosus. For this we use simple, but unconventional, graphic representations of the data, based on difference plots and ratio plots. Differences between patients with Burkitt's lymphoma...... and systemic lupus erythematosus from another previously published study (Macanovic, M. and Lachmann, P.J. (1979) Clin. Exp. Immunol. 38, 274) are also represented using ratio plots. Our observations indicate that analysis by regression analysis may often be misleading....

  15. Spiral CT and radiation dose

    International Nuclear Information System (INIS)

    Imhof, H.; Schibany, N.; Ba-Ssalamah, A.; Czerny, C.; Hojreh, A.; Kainberger, F.; Krestan, C.; Kudler, H.; Noebauer, I.; Nowotny, R.

    2003-01-01

    Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981. Nowadays there are several modifications of the CTDI values, which may lead to confusion. It is suggested to use the standardized CTDI-100 w. value together with the dose length product in all CT-examinations. These values should be printed on all CT-images and allows an evaluation of the individualized patient dose. Nowadays, radiologist's aim must be to work at the lowest maximal diagnostic acceptable signal to noise ratio. To decrease radiation dose radiologist should use low kV and mA, but high pitches. Newly developed CT-dose-reduction soft-wares and filters should be installed in all CT-machines. We should critically compare the average dose used for a specific examination with the reference dose used in this country and/or Europe. Greater differences should caution the radiologist. Finally, we as radiologists must check very carefully all indications and recommend alternative imaging methods. But we have also to teach our customers--patients and medical doctors who are non-radiologists--that a 'good' image is not that which show all possible information, but that which visualize 'only' the diagnostic necessary information

  16. Potential support ratios

    DEFF Research Database (Denmark)

    Kjærgaard, Søren; Canudas-Romo, Vladimir

    2017-01-01

    , the prospective potential support ratio usually focuses on the current mortality schedule, or period life expectancy. Instead, in this paper we look at the actual mortality experienced by cohorts in a population, using cohort life tables. We analyse differences between the two perspectives using mortality models......, historical data, and forecasted data. Cohort life expectancy takes future mortality improvements into account, unlike period life expectancy, leading to a higher prospective potential support ratio. Our results indicate that using cohort instead of period life expectancy returns around 0.5 extra younger...

  17. The rectilinear Steiner ratio

    Directory of Open Access Journals (Sweden)

    PO de Wet

    2005-06-01

    Full Text Available The rectilinear Steiner ratio was shown to be 3/2 by Hwang [Hwang FK, 1976, On Steiner minimal trees with rectilinear distance, SIAM Journal on Applied Mathematics, 30, pp. 104– 114.]. We use continuity and introduce restricted point sets to obtain an alternative, short and self-contained proof of this result.

  18. The Reference Return Ratio

    DEFF Research Database (Denmark)

    Nicolaisen, Jeppe; Faber Frandsen, Tove

    2008-01-01

    The paper introduces a new journal impact measure called The Reference Return Ratio (3R). Unlike the traditional Journal Impact Factor (JIF), which is based on calculations of publications and citations, the new measure is based on calculations of bibliographic investments (references) and returns...

  19. Comparison of measured and calculated contralateral breast doses in whole breast radiotherapy for VMAT and standard tangent techniques

    International Nuclear Information System (INIS)

    Tse, T.L.J; Bromley, R.; Booth, J.; Gray, A.

    2011-01-01

    Full text: Objective This study aims to evaluate the accuracy of calculated dose with the Eclipse analytical anisotropic algorithm (AAA) for contralateral breast (CB) in left-sided breast radiotherapy for dual-arc VMA T and standard wedged tangent (SWT) techniques. Methods and materials Internal and surface CB doses were measured with EBT2 film in an anthropomorphic phantom mounted with C-cup and D-cup breasts. The measured point dose was approximated by averaging doses over the 4 x 4 mm 2 central region of each 2 x 2 cm2 piece of film. The dose in the target region of the breast was also measured. The measured results were compared to AAA calculations with calculation grids of I, 2.5 and 5 mm. Results In SWT plans, the average ratios of calculation to measurement for internal doses were 0.63 ± 0.081 and 0.5 I ± 0.28 in the medial and lateral aspects, respectively. Corresponding ratios for surface doses were 0.88 ± 0.22 and 0.38 ± 0.38. In VMAT plans, however, the calculation accuracies showed little dependence on the measurement locations, the ratios were 0.78 ± O. I I and 0.81 ± 0.085 for internal and surface doses. In general, finer calculation resolutions did not inevitably improve the dose estimates of internal doses. For surface doses, using smaller grid size I mm could improve the calculation accuracies on the medial but not the lateral aspects of CB. Conclusion In all plans, AAA had a tendency to underestimate both internal and surface CB doses. Overall, it produces more accurate results in VMAT than SWT plans.

  20. Analysis of dose in heterogeneity adjuvant radiotherapy after surgical treatment of cases of breast cancer

    International Nuclear Information System (INIS)

    Grechi, Bruna E.; Schwarz, Ana Paula; Teston, Adriano; Rodrigues, Joanilso S.

    2013-01-01

    Assuming the systems planning radiotherapy recognize all body structures of the same density (d=1 g/cm³), variations in electron density within the irradiated area, as is the case of patients who undergo reconstruction mammary processes and use tissue expanders, may influence the dose distribution in the treatment and may produce heterogeneities which are not measured by changing its actual distribution into healthy tissues or in the target volume to be irradiated. Through the calculation of the algorithms' dose distribution of the XiO® planning system (Fast Fourier Transform, Convolution, Superposition, Fast Superposition e Clarkson), when using correction of heterogeneity between tissues of different densities, there was obtained a percentage ratio of dose increase in the structures of interest, and of the amount of absorbed dose by healthy organs adjacent to the target volume. (author)

  1. Directional gear ratio transmissions

    Science.gov (United States)

    Lafever, A. E. (Inventor)

    1984-01-01

    Epicyclic gear transmissions which transmit output at a gear ratio dependent only upon the input's direction are considered. A transmission housing envelops two epicyclic gear assemblies, and has shafts extending from it. One shaft is attached to a sun gear within the first epicyclic gear assembly. Planet gears are held symmetrically about the sun gear by a planet gear carrier and are in mesh with both the sun gear and a ring gear. Two unidirectional clutches restrict rotation of the first planet gear carrier and ring gear to one direction. A connecting shaft drives a second sun gear at the same speed and direction as the first planet gear carrier while a connecting portion drives a second planet gear carrier at the same speed and direction as the first ring gear. The transmission's output is then transmitted by the second ring gear to the second shaft. Input is transmitted at a higher gear ratio and lower speed for all inputs in the first direction than in the opposite direction.

  2. Investigations of peripheral dose for helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lissner, Steffen; Schubert, Kai; Sterzing, Florian; Herfarth, Klaus; Sroka-Perez, Gabriele; Debus, Juergen [University Hospital Heidelberg (Germany). Dept. of Radiation Oncology; Wiezorek, Tilo [University Hospital Jena (Germany). Dept. of Radiotherapy

    2013-07-01

    Purpose: Whenever treating a patient with percutaneous radiotherapy, a certain amount of dose is inevitably delivered to healthy tissue. This is mainly due to beam's entry and exit in the region of the target volume. In regions distant from the target volume, dose is delivered by leakage from the MLC and head scatter from the accelerator head and phantom scatter from the target volume (peripheral dose). Helical tomotherapy is a form of radiation therapy with a uniquely designed machine and delivery pattern which influence the peripheral dose. The goal of this work was to investigate peripheral dose in helical tomotherapy. The experiments were used to establish a complex characterization of the peripheral dose. Materials and methods: A 30*30*60cm{sup 3} slab phantom and TLD-100 (Lithium fluoride) were used for the experiments. Treatment procedures were generated with the tomotherapy planning system (TPS). Additionally, procedures were created on the Operator Station of the tomotherapy system without a calculation of the dose distribution. The peripheral dose which was produced by a typical tomotherapy treatment plan was measured. Furthermore, these procedures were used to differentiate the parts of the peripheral dose in phantom scatter dose and head scatter and leakage dose. Additionally, the relation between peripheral dose and treatment time and between peripheral dose and delivered dose was investigated. Additionally, the peripheral dose was measured in an Alderson phantom. Results: Distances of 30cm or more resulted in a decrease of the peripheral dose to less than 0.1% of the target dose. The measured doses have an offset of approximately 1cGy in comparison to the calculated doses from the TPS. The separated head scatter and leakage dose was measured in the range of 1cGy for typical treatments. Furthermore, the investigations show a linear correlation between head scatter leakage dose and treatment time and between scatter dose parts and delivered dose. A

  3. Peak power ratio generator

    Science.gov (United States)

    Moyer, R.D.

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  4. Thermal neutron dose calculation in synovium membrane for BNCS

    International Nuclear Information System (INIS)

    Abdalla, Khalid; Naqvi, A.A.; Maalej, N.; El-Shahat, B.

    2006-01-01

    A D(d,n) reaction based setup has been optimized for Boron Neutron Capture Synovectomy (BNCS). The polyethylene moderator and graphite reflector sizes were optimized to deliver the highest ratio of thermal to fast neutron yield. The neutron dose was calculated at various depths in a knee phantom loaded with boron to determine therapeutic ratios of synovium dose/skin dose and synovium dose/bone dose. Normalized to same boron loading in synovium, the values of the therapeutic ratios obtained in the present study are 12-30 times higher than the published values. (author)

  5. D-optimal experimental designs to test for departure from additivity in a fixed-ratio mixture ray.

    Science.gov (United States)

    Coffey, Todd; Gennings, Chris; Simmons, Jane Ellen; Herr, David W

    2005-12-01

    Traditional factorial designs for evaluating interactions among chemicals in a mixture may be prohibitive when the number of chemicals is large. Using a mixture of chemicals with a fixed ratio (mixture ray) results in an economical design that allows estimation of additivity or nonadditive interaction for a mixture of interest. This methodology is extended easily to a mixture with a large number of chemicals. Optimal experimental conditions can be chosen that result in increased power to detect departures from additivity. Although these designs are used widely for linear models, optimal designs for nonlinear threshold models are less well known. In the present work, the use of D-optimal designs is demonstrated for nonlinear threshold models applied to a fixed-ratio mixture ray. For a fixed sample size, this design criterion selects the experimental doses and number of subjects per dose level that result in minimum variance of the model parameters and thus increased power to detect departures from additivity. An optimal design is illustrated for a 2:1 ratio (chlorpyrifos:carbaryl) mixture experiment. For this example, and in general, the optimal designs for the nonlinear threshold model depend on prior specification of the slope and dose threshold parameters. Use of a D-optimal criterion produces experimental designs with increased power, whereas standard nonoptimal designs with equally spaced dose groups may result in low power if the active range or threshold is missed.

  6. Odor concentration invariance by chemical ratio coding

    Directory of Open Access Journals (Sweden)

    Naoshige Uchida

    2008-08-01

    Full Text Available Many animal species rely on chemical signals to extract ecologically important information from the environment. Yet in natural conditions chemical signals will frequently undergo concentration changes that produce differences in both level and pattern of activation of olfactory receptor neurons. Thus, a central problem in olfactory processing is how the system is able to recognize the same stimulus across different concentrations. To signal species identity for mate recognition, some insects use the ratio of two components in a binary chemical mixture to produce a code that is invariant to dilution. Here, using psychophysical methods, we show that rats also classify binary odor mixtures according to the molar ratios of their components, spontaneously generalizing over at least a tenfold concentration range. These results indicate that extracting chemical ratio information is not restricted to pheromone signaling and suggest a general solution for concentration-invariant odor recognition by the mammalian olfactory system.

  7. Regulatory requirements for marketing fixed dose combinations

    Directory of Open Access Journals (Sweden)

    B G Jayasheel

    2010-01-01

    Full Text Available The development of fixed-dose combinations (FDCs is becoming increasingly important from a public health perspective. FDCs have advantages when there is an identifiable patient population for whom treatment with a particular combination of actives in a fixed ratio is safe and effective and when all of the actives contribute to the overall therapeutic effect. Such combinations of drugs are particularly useful in the management of chronic diseases. In addition, there can be real clinical benefits in the form of increased efficacy and/or a reduced incidence of adverse effects. Additional advantages of FDCs are potentially lower costs of manufacturing compared to the costs of producing separate products administered concurrently, simpler logistics of distribution and reduced development of resistance in the case of antimicrobials. Above all, FDC therapy reduces pill burden and improves medication compliance. Although, FDCs seem to be ideal under certain pre-defined circumstances, if a dosing adjustment is warranted, there may not be an FDC available in the most appropriate strength for the patient and if an adverse drug reaction occurs from using an FDC, it may be difficult to identify the active ingredient responsible for causing the reaction. Appendix VI of Schedule Y (Drugs & Cosmetics Rules 1945, India states the requirements for marketing approval of various types of FDCs. The same is further elaborated in this article to provide a detailed guidance including the clinical trial requirements. However, the heterogeneity of the therapeutic field makes it difficult to develop a standard guidance document.

  8. The therapeutic ratio in BNCT: Assessment using the Rat 9L gliosarcoma brain tumor and spinal cord models

    International Nuclear Information System (INIS)

    Coderre, J.A.; Micca, P.L.; Nawrocky, M.M.; Fisher, C.D.; Bywaters, A.; Morris, G.M.; Hopewell, J.W.

    1996-01-01

    During any radiation therapy, the therapeutic tumor dose is limited by the tolerance of the surrounding normal tissue within the treatment volume. The short ranges of the products of the 10 B(n,α) 7 Li reaction produced during boron neutron capture therapy (BNCT) present an opportunity to increase the therapeutic ratio (tumor dose/normal tissue dose) to levels unprecedented in photon radiotherapy. The mixed radiation field produced during BNCT comprises radiations with different linear energy transfer (LET) and different relative biological effectiveness (RBE). The short ranges of the two high-LET products of the 'B(n,a)'Li reaction make the microdistribution of the boron relative to target cell nuclei of particular importance. Due to the tissue specific distribution of different boron compounds, the term RBE is inappropriate in defining the biological effectiveness of the 10 B(n,α) 7 Li reaction. To distinguish these differences from true RBEs we have used the term open-quotes compound biological effectivenessclose quotes (CBE) factor. The latter can be defined as the product of the true, geometry-independent, RBE for these particles times a open-quotes boron localization factorclose quotes, which will most likely be different for each particular boron compound. To express the total BNCT dose in a common unit, and to compare BNCT doses with the effects of conventional photon irradiation, multiplicative factors (RBEs and CBEs) are applied to the physical absorbed radiation doses from each high-LET component. The total effective BNCT dose is then expressed as the sum of RBE-corrected physical absorbed doses with the unit Gray-equivalent (Gy-Eq)

  9. CT doses in cylindrical phantoms

    International Nuclear Information System (INIS)

    Atherton, J.V.; Huda, W.

    1995-01-01

    A single CT scan of thickness T in a cylindrical phantom produces a three-dimensional dose distribution, which depends primarily on the photon energy spectrum, the x-ray beam shaping filter and the size and composition of the irradiated phantom. Monte Carlo simulations employing monoenergetic photons were employed to investigate the effect of each of these factors on phantom dose distributions. The fractional energies scattered, imparted and transmitted through the CT phantom were calculated. A dose index (D(r)), which is a function of phantom radius r, was computed. Phantom materials investigated included lung, fat, water, soft tissue, acrylic and bone with calculations performed for head (160 mm diameter) and body (320 mm diameter) phantoms. All dose and energy imparted data generated for CT phantoms were normalized using an 'in air' dose (D air ), which is defined as the axial dose (in acrylic) at the isocentre in the absence of any phantom. Results obtained show how CT parameters impact on doses in cylindrical phantoms. These dosimetry data are likely to be useful to estimate energy imparted to phantoms (and patients) undergoing CT examinations. (author)

  10. Clinical uses of I-123 produced by 127I(p, 5n)123Xe to 123I reaction in NIRS

    International Nuclear Information System (INIS)

    Saegusa, Kenji; Arimizu, Noboru; Uchiyama, Guio; Tateno, Yukio; Rikitake, Tomoyuki.

    1978-01-01

    123 I capsules produced by NIRS which are believed to be uncontaminated by radioactive impurities other than 125 I were compared with commercial 123 I capsules regarding gamma-ray spectra, thyroid phantoms and clinical scintigrams. Absorbed radiation doses of 123 I contaminated with nuclides other than 123 I to thyroid and whole body were also estimated. Regarding gamma-ray spectra, any nuclides other than 125 I(0.53%) did not contaminate in 123 I produced by NIRS, and it was superior to commercial capsules. Regarding phantoms and clinical scintigrams, background counts around the thyroid gland seemed to be slightly higher in commercial capsules than that produced by NIRS because of contamination with other nuclides. Exposed doses in thyroid and whole body were counted. Ratios in thyroid and whole body were increased by 30% and 9%, respectively in 123 I produced by NIRS because of contamination with 0.53% of 125 I in the event that the intake ratio of thyroid was determined as 25%. In commercial capsules the doses in thyroid and whole body were increased by 500% and 150%, respectively. Doses of commercial capsules and NIRS capsules were 7.87 rad and 1.72 rad, respectively per 100 μCi in thyroid. The ratio of NIRS capsules to commercial capsules in thyroid was 1/4.6, and that in the whole body was less than 1/2. (Ichikawa, K.)

  11. Energy Profit Ratio Compared

    International Nuclear Information System (INIS)

    Amano, Osamu

    2007-01-01

    We need more oil energy to take out oil under the ground. Limit resources make us consider other candidates of energy source instead of oil. Electricity shall be the main role more and more like electric vehicles and air conditioners so we should consider electricity generation ways. When we consider what kind of electric power generation is the best or suitable, we should not only power generation plant but whole process from mining to power generation. It is good way to use EPR, Energy Profit Ratio, to analysis which type is more efficient and which part is to do research and development when you see the input breakdown analysis. Electricity by the light water nuclear power plant, the hydrogen power plant and the geothermal power plant are better candidates from EPR analysis. Forecasting the world primly energy supply in 2050, it is said that the demand will be double of the demand in 2000 and the supply will not be able to satisfy the demand in 2050. We should save 30% of the demand and increase nuclear power plants 3.5 times more and recyclable energy like hydropower plants 3 times more. When the nuclear power plants are 3.5 times more then uranium peak will come and we will need breed uranium. I will analysis the EPR of FBR. Conclusion: A) the EPR of NPS in Japan is 17.4 and it is the best of all. B) Many countries will introduce new nuclear power plants rapidly may be 3.5 times in 2050. C) Uranium peak will happen around 2050. (author)

  12. Effect of Residential Radon Decay Product Dose Factor Variability on Reporting of Dose.

    Science.gov (United States)

    Harley, Naomi H

    2018-04-01

    Guidelines for occupational exposure to radiation are based on annual absorbed or effective dose. Guidelines for Rn exposure are currently based on air concentrations of Rn or decay products. Models of bronchial dose from decay product exposure are based on calculations that have five major parameters with parameter variabilities ranging from 20 to 50%. Many countries currently use the ICRP dose conversion convention, which is a ratio of lifetime Rn lung cancer risk to lifetime atomic bomb dose risk. The results of ongoing epidemiology changed both lifetime risk values, and the dose conversion convention has increased by a factor of 2. Therefore, the current dose conversion convention risk ratio is to be replaced by biokinetic dosimetric models. The main effect of variability in the value of Rn dose factors on industry is that the workplace atmosphere must be characterized accurately, and at present, this is not possible. A history of the dose factor models is central to factor development. The values of the dose model parameters are described illustrating the difficulty in calculation of a dose factor with universal applicability. The objective is to show the range of each parameter and the effect of the dose factor used when reporting occupational or residential bronchial dose.

  13. A snail with unbiased population sex ratios but highly biased brood sex ratios.

    Science.gov (United States)

    Yusa, Yoichi; Suzuki, Yoshito

    2003-01-01

    Extraordinary sex ratio patterns and the underlying sex-determining mechanisms in various organisms are worth investigating, particularly because they shed light on adaptive sex-ratio adjustment. Here, we report an extremely large variation in the brood sex ratio in the freshwater snail, Pomacea canaliculata. In eight rearing series originating from three wild populations, sex ratios were highly variable among broods, ranging continuously from almost exclusively males to almost exclusively females. However, sex ratios were similar between broods from the same mating pair, indicating that sex ratio is a family trait. Irrespective of the large variations, the average sex ratios in all rearing series were not significantly different from 0.5. We argue that Fisher's adaptive sex-ratio theory can explain the equal average sex ratios, and the results, in turn, directly support Fisher's theory. Polyfactorial sex determination (in which sex is determined by three or more genetic factors) is suggested as the most likely mechanism producing the variable brood sex ratio. PMID:12614578

  14. WE-FG-BRA-05: Potential Clinical Benefit of LINAC Flattening-Filter-Free (FFF) Mode - Improvement of Treatment Therapeutic Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Chang, S [Department of Radiation Oncology, UNC School of Medicine, Chapel Hill, NC (United States); Department of Biomedical Engineering, University of North Carolina- Chapel Hill/ North Carolina State University, Chapel Hill, North Carolina (United States); Lineberger Clinical Cancer Center, University of North Carolina, Chapel Hill, NC (United States); Rivera, J [Department of Biomedical Engineering, University of North Carolina- Chapel Hill/ North Carolina State University, Chapel Hill, North Carolina (United States); Tian, H [Xuzhou Medical College, Xuzhou, Jiangsu (China); Lineberger Clinical Cancer Center, University of North Carolina, Chapel Hill, NC (United States); Price, A [Department of Radiation Oncology, UNC School of Medicine, Chapel Hill, NC (United States); Santos, C [Lineberger Clinical Cancer Center, University of North Carolina, Chapel Hill, NC (United States); Zhang, Y [Department of Radiation Oncology, UNC School of Medicine, Chapel Hill, NC (United States); Xuzhou Medical College, Xuzhou, Jiangsu (China); Lineberger Clinical Cancer Center, University of North Carolina, Chapel Hill, NC (United States)

    2016-06-15

    Purpose: Ultrahigh dose-rate radiation at >40Gy/s has demonstrated astonishing normal-tissue sparing and tumor control in recent preclinical naive and tumor-bearing rodent studies when compared to the same radiation dose at a conventional dose-rate. The working mechanism of this fascinating dose-rate effect is currently under investigation. The aims of this work include investigating 1) whether LINAC FFF mode radiation at approximately 1Gy/s also has an improved therapeutic ratio compared to the same radiation dose at the conventional dose-rate of 0.05Gy/s, and 2) the dose-rate effect’s potential working mechanism by studying the expression of the P53 gene, linked to tumor suppression and cell regulation after radiation damage. Methods: We used mouse model C57BL/6J, the same as that used in the ultrahigh dose-rate studies, and exposed them to total body irradiation (TBI) using the Elekta Versa accelerator 10MV photons. Mice (N=20) were given a total dose of 12Gy in both the high dose-rate group (n=10) using the FFF-mode and the conventional dose-rate group (n=10) using the conventional does rate mode. The FFF-mode treatment setup consisted of a 15cm×15cm field size setting at 53.2cm SSD while the conventional-mode set-up consisted of a 10cm×10cm field size at 100SSD. Post-radiation, animals were monitored daily for survival analysis and signs of moribundity requiring euthanasia. In addition, mouse spleens were harvested for P53 analysis at different time points. Results: For 12Gy TBI, the 1.3Gy/s FFF-mode high dose-rate produced a statistically significant (p=0.02) improvement in mouse survival compared to the 0.05Gy/s conventional dose-rate. An initial P53 study at the time of death time-point indicates that high dose-rate radiation induced a stronger expression of P53 than conventional dose-rate radiation. Conclusion: Our pilot study indicates that the FFF-mode high dose-rate radiation, which has been used largely to improve clinical throughput, may provide

  15. WE-FG-BRA-05: Potential Clinical Benefit of LINAC Flattening-Filter-Free (FFF) Mode - Improvement of Treatment Therapeutic Ratio

    International Nuclear Information System (INIS)

    Chang, S; Rivera, J; Tian, H; Price, A; Santos, C; Zhang, Y

    2016-01-01

    Purpose: Ultrahigh dose-rate radiation at >40Gy/s has demonstrated astonishing normal-tissue sparing and tumor control in recent preclinical naive and tumor-bearing rodent studies when compared to the same radiation dose at a conventional dose-rate. The working mechanism of this fascinating dose-rate effect is currently under investigation. The aims of this work include investigating 1) whether LINAC FFF mode radiation at approximately 1Gy/s also has an improved therapeutic ratio compared to the same radiation dose at the conventional dose-rate of 0.05Gy/s, and 2) the dose-rate effect’s potential working mechanism by studying the expression of the P53 gene, linked to tumor suppression and cell regulation after radiation damage. Methods: We used mouse model C57BL/6J, the same as that used in the ultrahigh dose-rate studies, and exposed them to total body irradiation (TBI) using the Elekta Versa accelerator 10MV photons. Mice (N=20) were given a total dose of 12Gy in both the high dose-rate group (n=10) using the FFF-mode and the conventional dose-rate group (n=10) using the conventional does rate mode. The FFF-mode treatment setup consisted of a 15cm×15cm field size setting at 53.2cm SSD while the conventional-mode set-up consisted of a 10cm×10cm field size at 100SSD. Post-radiation, animals were monitored daily for survival analysis and signs of moribundity requiring euthanasia. In addition, mouse spleens were harvested for P53 analysis at different time points. Results: For 12Gy TBI, the 1.3Gy/s FFF-mode high dose-rate produced a statistically significant (p=0.02) improvement in mouse survival compared to the 0.05Gy/s conventional dose-rate. An initial P53 study at the time of death time-point indicates that high dose-rate radiation induced a stronger expression of P53 than conventional dose-rate radiation. Conclusion: Our pilot study indicates that the FFF-mode high dose-rate radiation, which has been used largely to improve clinical throughput, may provide

  16. A Monte Carlo Study of dose enhancement according to the enhancement agents

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Hoon; Kim, Chang Soo [Dept. of Radiological Science, College of Health Sciences, Catholic University of Pusan, Busan (Korea, Republic of); Hwang, Chul Hwan [Dept. of Radiation Oncology, Pusan National University Hospital, Busan (Korea, Republic of)

    2017-03-15

    Dose enhancement effects at megavoltage (MV) X and γ-ray energies, and the effects of different energy levels on incident energy, dose enhancement agents, and concentrations were analyzed using Monte Carlo simulations. Gold, gadolinium, Iodine, and iron oxide (Fe2O3) were compared as dose enhancement agents. For incident energy, 4, 6, 10 and 15 MV X-ray spectra produced by a linear accelerator and a Co60 γ-ray were used. The dose enhancement factor (DEF) was calculated using an ICRU Slab phantom for concentrations of 7, 18, and 30 mg/g. The DEF was higher at higher concentrations of dose enhancement agents and at lower incident energies. The calculated DEF ranged from 1.035 to 1.079, and dose enhancement effects were highest for iron oxide, followed by iodine, gadolinium, and gold. Thus, this study contributes to improving the therapeutic ratio by delivering larger doses of radiation to tumor volume, and provides data to support further in vivo and in vitro studies.

  17. Analysis of environmental and occupational doses from brachytherapy procedures

    International Nuclear Information System (INIS)

    Lima, Luciana Pinheiro de; Almeida, Adelaide de

    2001-01-01

    Lithium Fluoride Thermoluminescent detectors (TLD) were used to obtain the doses received by a physician and a physicist involved in braquitherapy procedures and also in measuring the dose in the treatment room. From the results, one can infer that: the physicist receives in his hands six times more doses preparing the probes, than the physician inserting them; the braquitherapy procedures, alone, are responsible for almost 25% of the total dose related to all radiotherapy activities; the environmental measurement doses related to high dose ratio were higher when compared to low dose ratio doses, once the radiation activity used was higher. From the results one can also infer that having a TLD dosimetry system for radiotherapy routine can be useful also to obtain the doses for radiation workers or for environment radiation in order to contribute to the institution quality assurance. (author)

  18. Optimization of hybrid iterative reconstruction level and evaluation of image quality and radiation dose for pediatric cardiac computed tomography angiography

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lin; Liang, Changhong [Southern Medical University, Guangzhou (China); Guangdong Academy of Medical Sciences, Dept. of Radiology, Guangdong General Hospital, Guangzhou (China); Zhuang, Jian [Guangdong Academy of Medical Sciences, Dept. of Cardiac Surgery, Guangdong Cardiovascular Inst., Guangdong Provincial Key Lab. of South China Structural Heart Disease, Guangdong General Hospital, Guangzhou (China); Huang, Meiping [Guangdong Academy of Medical Sciences, Dept. of Radiology, Guangdong General Hospital, Guangzhou (China); Guangdong Academy of Medical Sciences, Dept. of Catheterization Lab, Guangdong Cardiovascular Inst., Guangdong Provincial Key Lab. of South China Structural Heart Disease, Guangdong General Hospital, Guangzhou (China); Liu, Hui [Guangdong Academy of Medical Sciences, Dept. of Radiology, Guangdong General Hospital, Guangzhou (China)

    2017-01-15

    Hybrid iterative reconstruction can reduce image noise and produce better image quality compared with filtered back-projection (FBP), but few reports describe optimization of the iteration level. We optimized the iteration level of iDose{sup 4} and evaluated image quality for pediatric cardiac CT angiography. Children (n = 160) with congenital heart disease were enrolled and divided into full-dose (n = 84) and half-dose (n = 76) groups. Four series were reconstructed using FBP, and iDose{sup 4} levels 2, 4 and 6; we evaluated subjective quality of the series using a 5-grade scale and compared the series using a Kruskal-Wallis H test. For FBP and iDose{sup 4}-optimal images, we compared contrast-to-noise ratios (CNR) and size-specific dose estimates (SSDE) using a Student's t-test. We also compared diagnostic-accuracy of each group using a Kruskal-Wallis H test. Mean scores for iDose{sup 4} level 4 were the best in both dose groups (all P < 0.05). CNR was improved in both groups with iDose{sup 4} level 4 as compared with FBP. Mean decrease in SSDE was 53% in the half-dose group. Diagnostic accuracy for the four datasets were in the range 92.6-96.2% (no statistical difference). iDose{sup 4} level 4 was optimal for both the full- and half-dose groups. Protocols with iDose{sup 4} level 4 allowed 53% reduction in SSDE without significantly affecting image quality and diagnostic accuracy. (orig.)

  19. Optimization of hybrid iterative reconstruction level and evaluation of image quality and radiation dose for pediatric cardiac computed tomography angiography

    International Nuclear Information System (INIS)

    Yang, Lin; Liang, Changhong; Zhuang, Jian; Huang, Meiping; Liu, Hui

    2017-01-01

    Hybrid iterative reconstruction can reduce image noise and produce better image quality compared with filtered back-projection (FBP), but few reports describe optimization of the iteration level. We optimized the iteration level of iDose 4 and evaluated image quality for pediatric cardiac CT angiography. Children (n = 160) with congenital heart disease were enrolled and divided into full-dose (n = 84) and half-dose (n = 76) groups. Four series were reconstructed using FBP, and iDose 4 levels 2, 4 and 6; we evaluated subjective quality of the series using a 5-grade scale and compared the series using a Kruskal-Wallis H test. For FBP and iDose 4 -optimal images, we compared contrast-to-noise ratios (CNR) and size-specific dose estimates (SSDE) using a Student's t-test. We also compared diagnostic-accuracy of each group using a Kruskal-Wallis H test. Mean scores for iDose 4 level 4 were the best in both dose groups (all P < 0.05). CNR was improved in both groups with iDose 4 level 4 as compared with FBP. Mean decrease in SSDE was 53% in the half-dose group. Diagnostic accuracy for the four datasets were in the range 92.6-96.2% (no statistical difference). iDose 4 level 4 was optimal for both the full- and half-dose groups. Protocols with iDose 4 level 4 allowed 53% reduction in SSDE without significantly affecting image quality and diagnostic accuracy. (orig.)

  20. Elucidating the role of dose in the biopharmaceutics classification of drugs: the concepts of critical dose, effective in vivo solubility, and dose-dependent BCS.

    Science.gov (United States)

    Charkoftaki, Georgia; Dokoumetzidis, Aristides; Valsami, Georgia; Macheras, Panos

    2012-11-01

    To develop a dose dependent version of BCS and identify a critical dose after which the amount absorbed is independent from the dose. We utilized a mathematical model of drug absorption in order to produce simulations of the fraction of dose absorbed (F) and the amount absorbed as function of the dose for the various classes of BCS and the marginal cases in between classes. Simulations based on the mathematical model of F versus dose produced patterns of a constant F throughout a wide range of doses for drugs of Classes I, II and III, justifying biowaiver claim. For Classes I and III the pattern of a constant F stops at a critical dose Dose(cr) after which the amount of drug absorbed, is independent from the dose. For doses higher than Dose(cr), Class I drugs become Class II and Class III drugs become Class IV. Dose(cr) was used to define an in vivo effective solubility as S(eff) = Dose(cr)/250 ml. Literature data were used to support our simulation results. A new biopharmaceutic classification of drugs is proposed, based on F, separating drugs into three regions, taking into account the dose, and Dose(cr), while the regions for claiming biowaiver are clearly defined.

  1. Risk after low radiation doses

    International Nuclear Information System (INIS)

    Streffer, C.

    1989-01-01

    The high-level data measured in radiation doses need to be extrapolated to lower dose ranges in order to be able to state the risk of leukaemia and cancer in low radiation doses. The assumption is that there is no threshold dose although there has been no scientific verification for this yet. Conceptual considerations concerning the radiation action mechanisms suggest that a threshold dose does not exist. The assumption is that leukaemia and cancer are induced by the fact that individual transformed and malignant cells possess a certain though low potential to cause a malignant disease (leukaemia or cancer). It is assumed that radiation exposure produces damage to the genetic material of the cell which results in a malignant transformation. The number of these events is greatly reduced by a highly effective repair mechanism. However, these repair processes at the DNA are not complete or may even result in a misrepair; even low radiation doses (less than 10 mSv, 1 rem) apparently may trigger such cellular effects (transformation). (orig./HSCH) [de

  2. Skin dose variation: influence of energy

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

    2004-01-01

    Full text: This research aimed to quantitatively evaluate the differences in percentage dose of maximum for 6MV and 18MV x-ray beams within the first lcm of interactions. Thus provide quantitative information regarding the basal, dermal and subcutaneous dose differences achievable with these two types of high-energy x-ray beams. Percentage dose of maximum build up curves are measured for most clinical field sizes using 6MV and 18MV x-ray beams. Calculations are performed to produce quantitative results highlighting the percentage dose of maximum differences delivered to various depths within the skin and subcutaneous tissue region by these two beams Results have shown that basal cell layer doses are not significantly different for 6MV and 18Mv x-ray beams At depths beyond the surface and basal cell layer there is a measurable and significant difference in delivered dose. This variation increases to 20% of maximum and 22% of maximum at Imm and 1cm depths respectively. The percentage variations are larger for smaller field sizes where the photon in phantom component of the delivered dose is the most significant contributor to dose By producing graphs or tables of % dose differences in the build up region we can provide quantitative information to the oncologist for consideration (if skin and subcutaneous tissue doses are of importance) during the beam energy selection process for treatment. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  3. Absorbed Dose and Dose Equivalent Calculations for Modeling Effective Dose

    Science.gov (United States)

    Welton, Andrew; Lee, Kerry

    2010-01-01

    While in orbit, Astronauts are exposed to a much higher dose of ionizing radiation than when on the ground. It is important to model how shielding designs on spacecraft reduce radiation effective dose pre-flight, and determine whether or not a danger to humans is presented. However, in order to calculate effective dose, dose equivalent calculations are needed. Dose equivalent takes into account an absorbed dose of radiation and the biological effectiveness of ionizing radiation. This is important in preventing long-term, stochastic radiation effects in humans spending time in space. Monte carlo simulations run with the particle transport code FLUKA, give absorbed and equivalent dose data for relevant shielding. The shielding geometry used in the dose calculations is a layered slab design, consisting of aluminum, polyethylene, and water. Water is used to simulate the soft tissues that compose the human body. The results obtained will provide information on how the shielding performs with many thicknesses of each material in the slab. This allows them to be directly applicable to modern spacecraft shielding geometries.

  4. Production ratio of pseudoscalar to vector mesons

    International Nuclear Information System (INIS)

    Chliapnikov, P.V.; Uvarov, V.A.

    1990-01-01

    The P/V ratio of directly produced pseudoscalar (P) to vector (V) mesons is analysed using the data on the K S 0 and K * (892) total inclusive cross sections in pp, π + p and K ± p reactions. The indication for a change of P/V from a value of about 1 at low energies, where the fragmentation processes dominate, to a value of 1/3, suggested by spin-statistics, at high energies is discussed. (orig.)

  5. Analysis of dose in heterogeneity adjuvant radiotherapy after surgical treatment of cases of breast cancer; Analise da heterogeneidade de dose em radioterapia adjuvante apos tratamento cirurgico de casos de cancer de mama

    Energy Technology Data Exchange (ETDEWEB)

    Grechi, Bruna E.; Schwarz, Ana Paula, E-mail: anapaulaschwarz@yahoo.com.br [Centro Universitario Franciscano (UNIFRA), Santa Maria, RS (Brazil); Teston, Adriano; Rodrigues, Joanilso S. [Clinica de Radioterapia Santa Maria, Santa Maria, RS (Brazil)

    2013-12-15

    Assuming the systems planning radiotherapy recognize all body structures of the same density (d=1 g/cm³), variations in electron density within the irradiated area, as is the case of patients who undergo reconstruction mammary processes and use tissue expanders, may influence the dose distribution in the treatment and may produce heterogeneities which are not measured by changing its actual distribution into healthy tissues or in the target volume to be irradiated. Through the calculation of the algorithms' dose distribution of the XiO® planning system (Fast Fourier Transform, Convolution, Superposition, Fast Superposition e Clarkson), when using correction of heterogeneity between tissues of different densities, there was obtained a percentage ratio of dose increase in the structures of interest, and of the amount of absorbed dose by healthy organs adjacent to the target volume. (author)

  6. Neutron fluence produced in medical accelerators

    International Nuclear Information System (INIS)

    Castro, R.C.; Silva, A.X. da; Crispim, V.R.

    2004-01-01

    Radiotherapy with photon and electron beams still represents the most diffused technique to control and treat tumour diseases. To increase the treatment efficiency, accelerators of higher energy are used, the increase of electron and photon energy is joined with generation of undesired fast neutron that contaminated the therapeutic beam and give a non-negligible contribution to the patient dose. In this work we have simulated with the MCNP4B code the produced neutron spectra in the interaction between the beam and the head to the accelerator and estimating the equivalent dose for neutrons by x-ray dose for aims far from the targets. (author)

  7. Antiproton radiotherapy: peripheral dose from secondary neutrons

    DEFF Research Database (Denmark)

    Fahimian, Benjamin P.; DeMarco, John J.; Keyes, Roy

    2009-01-01

    is the normal tissue dose resulting from secondary neutrons produced in the annihilation of antiprotons on the nucleons of the target atoms. Here we present the first organ specific Monte Carlo calculations of normal tissue equivalent neutron dose in antiproton therapy through the use of a segmented CT......-based human phantom. The MCNPX Monte Carlo code was employed to quantify the peripheral dose for a cylindrical spread out Bragg peak representing a treatment volume of 1 cm diameter and 1 cm length in the frontal lobe of a segmented whole-body phantom of a 38 year old male. The secondary neutron organ dose...

  8. Estimation of radiation risks at low dose

    International Nuclear Information System (INIS)

    1990-04-01

    The report presents a review of the effects caused by radiation in low doses, or at low dose rates. For the inheritable (or ''genetic''), as well as for the cancer producing effects of radiation, present evidence is consistent with: (a) a non-linear relationship between the frequency of at least some forms of these effects, with comparing frequencies caused by doses many times those received annually from natural sources, with those caused by lower doses; (b) a probably linear relationship, however, between dose and frequency of effects for dose rates in the region of that received from natural sources, or at several times this rate; (c) no evidence to indicate the existence of a threshold dose below which such effects are not produced, and a strong inference from the mode of action of radiation on cells at low dose rates that no such thresholds are likely to apply to the detrimental, cancer-producing or inheritable, effects resulting from unrepaired damage to single cells. 19 refs

  9. Surface dose in intracavitary orthovoltage radiotherapy

    International Nuclear Information System (INIS)

    Podgorsak, M.B.; Schreiner, L.J.; Podgorsak, E.B.

    1990-01-01

    Radiotherapy with orthovoltage techniques is often the prime treatment for localized superficial malignancies. Surface doses and depth doses measured with cylindrical and end-window Farmer chambers are presented for various orthovoltage x-ray beams in the range from 80 to 300 kVp, both for open beams and beams collimated with commercial intracavitary leaded-glass cones. For radiation fields collimated by a diaphragm positioned at a distance from the patient surface (open beams) there is a small skin-sparing effect. On the other hand, the surface doses with commercial leaded-glass intracavitary cones can exhibit a fivefold increase compared to the open-beam dose maxima. Beyond a depth of ∼0.2 mm in a tissue-equivalent phantom, the doses measured for open beams and beams collimated with intracavitary cones are essentially identical. The increase in the surface dose observed with intracavitary cones is attributed to photoelectrons and recoil electrons produced in the cones. The high surface doses are measured by thin-wall parallel-plate ionization chambers but cannot be measured with cylindrical Farmer chambers since these chambers have wall thicknesses too large for the transmission of electrons produced in the cone. Since cylindrical Farmer chambers are typically used for calibration of radiation output, the high surface doses produced by the intracavitary cones may be overlooked; they can, however, be reduced to open-beam values by simple modifications to the cones

  10. CANCER RISKS ATTRIBUTABLE TO LOW DOSES OF IONIZING RADIATION - ASSESSING WHAT WE REALLY KNOW?

    Science.gov (United States)

    Cancer Risks Attributable to Low Doses of Ionizing Radiation - What Do We Really Know?AbstractHigh doses of ionizing radiation clearly produce deleterious consequences in humans including, but not exclusively, cancer induction. At very low radiation doses the situatio...

  11. NOTE: Comparison of head and body organ doses in CT

    Science.gov (United States)

    Huda, Walter; Ogden, Kent M.

    2008-01-01

    We compare head and body organ doses received by adult patients undergoing whole body scans operated using the same technique factors. Dosimetry data were obtained for six CT scanners (16 and 64 slice) from four vendors. Organ doses were obtained using the ImPACT CT dose software package for an adult male, together with the corresponding head and body CTDIw. Our data provide a link between the CTDI doses generated on most commercial scanners for each clinical CT examination and doses to organs and tissues within the directly irradiated region of an adult patient. The average numerical ratio of the brain dose to the head phantom CTDIw is 0.84 ± 0.05, the average ratio of the lung dose and liver dose to the body phantom CTDIw is 1.65 ± 0.05 and 1.48 ± 0.05, respectively. When scanned under identical conditions, lung doses are similar to brain doses, and liver doses are only ~10% lower. By comparison, the average body to head CTDIw ratio was 0.49 ± 0.06, which erroneously implies that doses to organs in the head are twice those of doses to organs in the body at the same techniques. Two CT dosimetry phantom sizes are therefore not required, and our findings support the need to reassess the role, if any, of current cylindrical acrylic dosimetry phantoms.

  12. Small Scale Variations in Carbon Oxygen Ratio

    International Nuclear Information System (INIS)

    Valkovic, Vladivoj; Sudac, Davorin; Nad, Karlo; Obhodas, Jasmina

    2013-06-01

    The aim of the research reported here is the development of a methodology for the measurement of small scale variations in chemical elements concentrations, in particular of carbon - oxygen ratio. Knowledge of the C/O ratio is of importance to many problems in various fields. Here we single out the application in obtaining important information about the oil fields. The most fundamental reservoir parameters - oil, gas and water content - are critical factors in determining how each oil field should be developed. It is well established that carbon to oxygen ratio log yields accurate and repeatable data that can be used to identify and monitor reserves depletion. Recent improvements in neutron generator and gamma detector technologies resulted in small devices which allowed through-tubing measurements. Although the ratio of carbon and oxygen yields is a measure of the amount of oil around the tool it should be realized that a carbon signal can originate from several sources including the borehole, the cement behind the casing, the formation rock and the formation fluid. In order to evaluate these contributions individually we are proposing the modification of the neutron generator by insertion of segmented associated alpha particle detector. From the measurement of time of flight spectra (alpha particle detector - start signal; gamma ray detector - stop signal) it would be possible to determine the location of gamma ray producing voxel and in such a way to determine radial variations in several chemical elements concentrations, in particular of carbon to oxygen ratio. (authors)

  13. When is a dose not a dose?

    International Nuclear Information System (INIS)

    Green, Patrick

    1992-01-01

    There is confusion over radiation dose limits between the International Commission on Radiological Protection, the National Radiological Protection Board and the Ministry of Agriculture, Fisheries and Food (MAFF), reports a Friends of the Earth's radiation campaigner. MAFF is suggesting the inadequate ICRP public dose limit does not apply to public exposures which arise from environmental contamination from past radioactive discharges. (author)

  14. Psychological distress during early gestation and offspring sex ratio

    DEFF Research Database (Denmark)

    Obel, C; Henriksen, TB; Secher, Niels Jørgen

    2007-01-01

    BACKGROUND: Exposure to severe stress in early pregnancy is associated with a lower male to female ratio (sex ratio), but whether more moderate levels of psychological discomfort have the same kind of effect is unknown. In a population based follow-up study, we aimed to test whether psychological...... Questionnaire (GHQ). RESULTS: We found an overall male to female ratio (sex ratio) of 1.03. There was an inverse dose response association (test for trend P ... suggest that not only severe stress, but also more moderate and common levels of psychological distress, may decrease the sex ratio in the offspring. Stress during pregnancy is a likely candidate involved in the decreasing sex ratio observed in many countries....

  15. Psychological distress during early gestation and offspring sex ratio

    DEFF Research Database (Denmark)

    Obel, Carsten; Henriksen, Tine Brink; Secher, Niels Jørgen

    2007-01-01

    BACKGROUND: Exposure to severe stress in early pregnancy is associated with a lower male to female ratio (sex ratio), but whether more moderate levels of psychological discomfort have the same kind of effect is unknown. In a population based follow-up study, we aimed to test whether psychological...... Questionnaire (GHQ). RESULTS: We found an overall male to female ratio (sex ratio) of 1.03. There was an inverse dose response association (test for trend P ... suggest that not only severe stress, but also more moderate and common levels of psychological distress, may decrease the sex ratio in the offspring. Stress during pregnancy is a likely candidate involved in the decreasing sex ratio observed in many countries. Udgivelsesdato: 2007-Nov...

  16. A comparison of quantum limited dose and noise equivalent dose

    Science.gov (United States)

    Job, Isaias D.; Boyce, Sarah J.; Petrillo, Michael J.; Zhou, Kungang

    2016-03-01

    Quantum-limited-dose (QLD) and noise-equivalent-dose (NED) are performance metrics often used interchangeably. Although the metrics are related, they are not equivalent unless the treatment of electronic noise is carefully considered. These metrics are increasingly important to properly characterize the low-dose performance of flat panel detectors (FPDs). A system can be said to be quantum-limited when the Signal-to-noise-ratio (SNR) is proportional to the square-root of x-ray exposure. Recent experiments utilizing three methods to determine the quantum-limited dose range yielded inconsistent results. To investigate the deviation in results, generalized analytical equations are developed to model the image processing and analysis of each method. We test the generalized expression for both radiographic and fluoroscopic detectors. The resulting analysis shows that total noise content of the images processed by each method are inherently different based on their readout scheme. Finally, it will be shown that the NED is equivalent to the instrumentation-noise-equivalent-exposure (INEE) and furthermore that the NED is derived from the quantum-noise-only method of determining QLD. Future investigations will measure quantum-limited performance of radiographic panels with a modified readout scheme to allow for noise improvements similar to measurements performed with fluoroscopic detectors.

  17. Effects of radiation dose reduction in Volume Perfusion CT imaging of acute ischemic stroke

    International Nuclear Information System (INIS)

    Othman, Ahmed E.; Brockmann, Carolin; Afat, Saif; Pjontek, Rastislav; Nikobashman, Omid; Brockmann, Marc A.; Wiesmann, Martin; Yang, Zepa; Kim, Changwon; Kim, Jong Hyo

    2015-01-01

    To examine the influence of radiation dose reduction on image quality and sensitivity of Volume Perfusion CT (VPCT) maps regarding the detection of ischemic brain lesions. VPCT data of 20 patients with suspected ischemic stroke acquired at 80 kV and 180 mAs were included. Using realistic reduced-dose simulation, low-dose VPCT datasets with 144 mAs, 108 mAs, 72 mAs and 36 mAs (80 %, 60 %, 40 % and 20 % of the original levels) were generated, resulting in a total of 100 datasets. Perfusion maps were created and signal-to-noise-ratio (SNR) measurements were performed. Qualitative analyses were conducted by two blinded readers, who also assessed the presence/absence of ischemic lesions and scored CBV and CBF maps using a modified ASPECTS-score. SNR of all low-dose datasets were significantly lower than those of the original datasets (p <.05). All datasets down to 72 mAs (40 %) yielded sufficient image quality and high sensitivity with excellent inter-observer-agreements, whereas 36 mAs datasets (20 %) yielded poor image quality in 15 % of the cases with lower sensitivity and inter-observer-agreements. Low-dose VPCT using decreased tube currents down to 72 mAs (40 % of original radiation dose) produces sufficient perfusion maps for the detection of ischemic brain lesions. (orig.)

  18. Effects of radiation dose reduction in Volume Perfusion CT imaging of acute ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Ahmed E. [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Eberhard Karls University Tuebingen, University Hospital Tuebingen, Department for Diagnostic and Interventional Radiology, Tuebingen (Germany); Brockmann, Carolin; Afat, Saif; Pjontek, Rastislav; Nikobashman, Omid; Brockmann, Marc A.; Wiesmann, Martin [RWTH Aachen University, Department of Diagnostic and Interventional Neuroradiology, Aachen (Germany); Yang, Zepa; Kim, Changwon [Seoul National University, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Suwon (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Kim, Jong Hyo [Seoul National University, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Suwon (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Center for Medical-IT Convergence Technology Research, Advanced Institute of Convergence Technology, Suwon (Korea, Republic of)

    2015-12-15

    To examine the influence of radiation dose reduction on image quality and sensitivity of Volume Perfusion CT (VPCT) maps regarding the detection of ischemic brain lesions. VPCT data of 20 patients with suspected ischemic stroke acquired at 80 kV and 180 mAs were included. Using realistic reduced-dose simulation, low-dose VPCT datasets with 144 mAs, 108 mAs, 72 mAs and 36 mAs (80 %, 60 %, 40 % and 20 % of the original levels) were generated, resulting in a total of 100 datasets. Perfusion maps were created and signal-to-noise-ratio (SNR) measurements were performed. Qualitative analyses were conducted by two blinded readers, who also assessed the presence/absence of ischemic lesions and scored CBV and CBF maps using a modified ASPECTS-score. SNR of all low-dose datasets were significantly lower than those of the original datasets (p <.05). All datasets down to 72 mAs (40 %) yielded sufficient image quality and high sensitivity with excellent inter-observer-agreements, whereas 36 mAs datasets (20 %) yielded poor image quality in 15 % of the cases with lower sensitivity and inter-observer-agreements. Low-dose VPCT using decreased tube currents down to 72 mAs (40 % of original radiation dose) produces sufficient perfusion maps for the detection of ischemic brain lesions. (orig.)

  19. Dose variations caused by setup errors in intracranial stereotactic radiotherapy: A PRESAGE study

    International Nuclear Information System (INIS)

    Teng, Kieyin; Gagliardi, Frank; Alqathami, Mamdooh; Ackerly, Trevor; Geso, Moshi

    2014-01-01

    Stereotactic radiotherapy (SRT) requires tight margins around the tumor, thus producing a steep dose gradient between the tumor and the surrounding healthy tissue. Any setup errors might become clinically significant. To date, no study has been performed to evaluate the dosimetric variations caused by setup errors with a 3-dimensional dosimeter, the PRESAGE. This research aimed to evaluate the potential effect that setup errors have on the dose distribution of intracranial SRT. Computed tomography (CT) simulation of a CIRS radiosurgery head phantom was performed with 1.25-mm slice thickness. An ideal treatment plan was generated using Brainlab iPlan. A PRESAGE was made for every treatment with and without errors. A prescan using the optical CT scanner was carried out. Before treatment, the phantom was imaged using Brainlab ExacTrac. Actual radiotherapy treatments with and without errors were carried out with the Novalis treatment machine. Postscan was performed with an optical CT scanner to analyze the dose irradiation. The dose variation between treatments with and without errors was determined using a 3-dimensional gamma analysis. Errors are clinically insignificant when the passing ratio of the gamma analysis is 95% and above. Errors were clinically significant when the setup errors exceeded a 0.7-mm translation and a 0.5° rotation. The results showed that a 3-mm translation shift in the superior-inferior (SI), right-left (RL), and anterior-posterior (AP) directions and 2° couch rotation produced a passing ratio of 53.1%. Translational and rotational errors of 1.5 mm and 1°, respectively, generated a passing ratio of 62.2%. Translation shift of 0.7 mm in the directions of SI, RL, and AP and a 0.5° couch rotation produced a passing ratio of 96.2%. Preventing the occurrences of setup errors in intracranial SRT treatment is extremely important as errors greater than 0.7 mm and 0.5° alter the dose distribution. The geometrical displacements affect dose delivery

  20. Dose from radiological examinations

    International Nuclear Information System (INIS)

    Imamura, Keiko; Uji, Teruyuki; Sakuyama, Keiko; Fujikawa, Mitsuhiro; Fujii, Masamichi

    1976-01-01

    Relatively high gonad doses, several hundred to one thousand mR, have been observed in case of pelvis, hip-joint, coccyx, lower abdomen and lumber examination. Dose to the ovary is especially high in barium enema and I.V.P. examinations. About 12 per cent of the 4-ray examination are high-dose. The gonad dose is relatively high in examination of abdomen and lower extremities, in infants. The dose to the eyes is especially high, 1.0 to 2.5R per exposure, in temporal bone and nasal sinuses tomography. X-ray doses have been compared with dose limits recommended by ICRP and with the gonad dose from natural radiations. The gonad dose in lumbar examination, barium enema, I.V.P. etc. is as high as the maximum permissible dose per year recommended by ICRP. Several devices have been made for dose reduction in the daily examinations: (1) separating the radiation field from the gonad by one centimeter decreases the gonad dose about one-half. (2) using sensitive screens and films. In pelvimetry and in infant hip-joint examination, the most sensitive screen and film are used. In the I.V.P. examination of adult, use of MS screen in place of FS screen decreases the dose to one-third, in combination with careful setting of radiation field, (3) use of grid increases the dose about 50 percent and the lead rubber protection (0.1mm lead equivalent) decreases the gonad dose to one-thirtieth in the spinal column examination of infant, (4) A lead protector, 1mm thickness and 2.5cm in diameter, on the eyes decreases the dose to about one-eighth in the face and nead examinations. These simple and effective methods for dose reduction. Should be carried out in as many examinations as possible in addition to observing dose limits recommended by ICRP. (Evans, J.)

  1. Benzodiazepine Initiation and Dose Escalation.

    Science.gov (United States)

    Skinner, Brian W; Johnston, Elizabeth V; Saum, Lindsay M

    2017-04-01

    Benzodiazepines (BZDs) place patients at a significant risk of falling. The current literature does not address if this risk is increased during initiation or dose escalations of BZDs. To determine if initiation or dose escalations of BZD regimens are associated with an increased risk of falls in hospitalized patients compared with patients maintained on their home dose or who had their dose decreased from baseline. This retrospective case-control study evaluated hospitalized patients aged 45 years or older who received a BZD. Patients who did not fall were collected in a 3:1 ratio to patients who fell. Comparisons were made between BZD regimens prior to admission and those 48 hours prior to the index date. The date of fall served as the index date for patients who fell, and the median time-to-fall served as the index date for all other patients. A total of 132 patients were included in the study (33 falls and 99 without a fall). No significant differences were noted in demographics, baseline mobility, or past medical history. Patients who fell had a significantly longer median length of stay (15 vs 10 days; P = 0.025). Additionally, patients who fell were more likely to have had their BZD regimen initiated or dose escalated compared with patients who did not fall (63.6% vs 41.4%; P = 0.043). The risk of falling while on a BZD is increased on initiation and dose escalations. Hospitals should ensure judicious use of BZDs in inpatients to reduce the risk of falls.

  2. Dose volume assessment of high dose rate 192IR endobronchial implants

    International Nuclear Information System (INIS)

    Cheng, B. Saw; Korb, Leroy J.; Pawlicki, Todd; Wu, Andrew

    1996-01-01

    Purpose: To study the dose distributions of high dose rate (HDR) endobronchial implants using the dose nonuniformity ratio (DNR) and three volumetric irradiation indices. Methods and Materials: Multiple implants were configured by allowing a single HDR 192 Ir source to step through a length of 6 cm along an endobronchial catheter. Dwell times were computed to deliver a dose of 5 Gy to points 1 cm away from the catheter axis. Five sets of source configurations, each with different dwell position spacings from 0.5 to 3.0 cm, were evaluated. Three-dimensional (3D) dose distributions were then generated for each source configuration. Differential and cumulative dose-volume curves were generated to quantify the degree of target volume coverage, dose nonuniformity within the target volume, and irradiation of tissues outside the target volume. Evaluation of the implants were made using the DNR and three volumetric irradiation indices. Results: The observed isodose distributions were not able to satisfy all the dose constraints. The ability to optimally satisfy the dose constraints depended on the choice of dwell position spacing and the specification of the dose constraint points. The DNR and irradiation indices suggest that small dwell position spacing does not result in a more homogeneous dose distribution for the implant. This study supports the existence of a relationship between the dwell position spacing and the distance from the catheter axis to the reference dose or dose constraint points. Better dose homogeneity for an implant can be obtained if the spacing of the dwell positions are about twice the distance from the catheter axis to the reference dose or dose constraint points

  3. Low-Dose Volume-Perfusion CT of the Brain: Effects of Radiation Dose Reduction on Performance of Perfusion CT Algorithms.

    Science.gov (United States)

    Othman, A E; Afat, S; Brockmann, C; Nikoubashman, O; Bier, G; Brockmann, M A; Nikolaou, K; Tai, J H; Yang, Z P; Kim, J H; Wiesmann, M

    2017-09-01

    We aimed to compare different computed tomography (CT) perfusion post-processing algorithms regarding image quality of perfusion maps from low-dose volume perfusion CT (VPCT) and their diagnostic performance regarding the detection of ischemic brain lesions. We included VPCT data of 21 patients with acute stroke (onset Perfusion maps (cerebral blood volume (CBV); cerebral blood flow (CBF) from original and low-dose datasets were generated using two different commercially available post-processing methods: deconvolution-based method (DC) and maximum slope algorithm (MS). The resulting DC and MS perfusion maps were compared regarding perfusion values, signal-to-noise ratio (SNR) as well as image quality and diagnostic accuracy as rated by two blinded neuroradiologists. Quantitative perfusion parameters highly correlated for both algorithms and both dose levels (r ≥ 0.613, p perfusion maps from simulated low-dose VPCT. However, MS produced CBF maps with significantly higher image quality and SNR than DC, indicating that MS might be more suitable for low-dose VPCT imaging.

  4. [Effective dose from pediatric CT in Iceland].

    Science.gov (United States)

    Gudjonsdottir, Jonina; Jonsdottir, Arna Bjork

    2017-11-01

    It is important to know the effective dose from computed tomography (CT) examinations. The aim of this study was to evaluate the effective dose from pediatric CT examinations in Iceland. For all pediatric CT exams (children examination type and dose length product was retrospectively collected from the Landspitali University Hospital's archives, as was the total number of CT examinations. The ratio of pediatric CT exams and the frequency of examination types were calculated and, for the three most common examinations, the effective dose and mean dose length product were calculated for five age groups. The total number of pediatric CT examinations was 662, 3,6% of all the CT examinations performed. The three most common pediatric CT examinations were head (40,3%), abdomen (15,6%) and thorax (10,3%). The mean effective dose in those was, in the above order: for children dose length product was above European diagnostic reference levels in most examination types and age groups. Possibilities for lower effective doses from pediatric CT examinations should be explored. For that purpose, the use of size specific dose estimates is recommended.

  5. Brookhaven Linac Isotope Producer

    Data.gov (United States)

    Federal Laboratory Consortium — The Brookhaven Linac Isoptope Producer (BLIP)—positioned at the forefront of research into radioisotopes used in cancer treatment and diagnosis—produces commercially...

  6. Methods of bone marrow dose calculation

    International Nuclear Information System (INIS)

    Taboaco, R.C.

    1982-02-01

    Several methods of bone marrow dose calculation for photon irradiation were analised. After a critical analysis, the author proposes the adoption, by the Instituto de Radioprotecao e Dosimetria/CNEN, of Rosenstein's method for dose calculations in Radiodiagnostic examinations and Kramer's method in case of occupational irradiation. It was verified by Eckerman and Simpson that for monoenergetic gamma emitters uniformly distributed within the bone mineral of the skeleton the dose in the bone surface can be several times higher than dose in skeleton. In this way, is also proposed the Calculation of tissue-air ratios for bone surfaces in some irradiation geometries and photon energies to be included in the Rosenstein's method for organ dose calculation in Radiodiagnostic examinations. (Author) [pt

  7. Inexplicably female-biased sex ratios in Melittobia wasps.

    Science.gov (United States)

    Abe, Jun; Kamimura, Yoshitaka; West, Stuart A

    2014-09-01

    The sex ratio behavior of parasitoid wasps in the genus Melittobia is scandalous. In contrast to the prediction of Hamilton's local mate competition theory, and the behavior of numerous other species, their extremely female-biased sex ratios (1-5% males) change little in response to the number of females that lay eggs on a patch. We examined the mating structure and fitness consequences of adjusting the sex ratio in M. australica and found that (1) the rate of inbreeding did not differ from that expected with random mating within each patch; (2) the fitness of females that produced less female-biased sex ratios (10 or 20% males) was greater than that of females who produced the sex ratio normally observed in M. australica. These results suggest that neither assortative mating nor asymmetrical competition between males can explain the extreme sex ratios. More generally, the finding that the sex ratios produced by females led to a decrease in their fitness suggests that the existing theory fails to capture a key aspect of the natural history of Melittobia, and emphasizes the importance of examining the fitness consequences of different sex ratio strategies, not only whether observed sex ratios correlate with theoretical predictions. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  8. Radioisotopes produced by neutron irradiation of food.

    Science.gov (United States)

    Albright, S; Seviour, R

    2016-04-01

    The use of neutrons for cargo interrogation has the potential to drastically improve threat detection. Previous research has focussed on the production of (24)Na, based on the isotopes produced in pharmaceuticals and medical devices. For both the total activity and the ingestion dose we show that a variety of isotopes contribute and that (24)Na is only dominant under certain conditions. The composition of the foods has a strong influence on the resulting activity and ingestion dose suggesting that the pharmaceuticals and medical devices considered initially are not a viable analogue for foodstuffs. There is an energy dependence to the isotopes produced due to the cross-sections of different reactions varying with neutron energy. We show that this results in different isotopes dominating the ingestion dose at different energies, which has not been considered in the previous literature. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Secondary Particles Produced by Hadron Therapy

    Directory of Open Access Journals (Sweden)

    Abdolkazem Ansarinejad

    2015-07-01

    Full Text Available Introduction Use of hadron therapy as an advanced radiotherapy technique is increasing. In this method, secondary particles are produced through primary beam interactions with the beam-transport system and the patient’s body. In this study, Monte Carlo simulations were employed to determine the dose of produced secondary particles, particularly neutrons during treatment. Materials and Methods In this study, secondary particles, produced by proton and ion beams, were simulated for a cancer treatment plan. In particular, we evaluated the distribution of secondary neutrons, produced by a 400 MeV/u carbon beam on an electronic crate, which was exposed to radiation field under radioactive conditions. The level of major secondary particles, particularly neutrons, irradiating the target, was evaluated, using FLUKA Monte Carlo code. Results The fluences and radiation doses were applied to determine the shielding efficiency of devices and the probability of radiation damage to nearby electronic systems. According to the results, by using maximum-energy carbon ions (400 MeV/u, electronic devices are exposed to a dose rate of 0.05 µSv/s and an integrated dose of about 34 mSv, each year. Conclusion The simulation results could provide significant information about radiation assessment; they could also be a major help for clinical facilities to meet shielding requirements. Moreover, such simulations are essential for determining the radiation level, which is responsible for radiation-induced damages.

  10. RATIO_TOOL - SOFTWARE FOR COMPUTING IMAGE RATIOS

    Science.gov (United States)

    Yates, G. L.

    1994-01-01

    Geological studies analyze spectral data in order to gain information on surface materials. RATIO_TOOL is an interactive program for viewing and analyzing large multispectral image data sets that have been created by an imaging spectrometer. While the standard approach to classification of multispectral data is to match the spectrum for each input pixel against a library of known mineral spectra, RATIO_TOOL uses ratios of spectral bands in order to spot significant areas of interest within a multispectral image. Each image band can be viewed iteratively, or a selected image band of the data set can be requested and displayed. When the image ratios are computed, the result is displayed as a gray scale image. At this point a histogram option helps in viewing the distribution of values. A thresholding option can then be used to segment the ratio image result into two to four classes. The segmented image is then color coded to indicate threshold classes and displayed alongside the gray scale image. RATIO_TOOL is written in C language for Sun series computers running SunOS 4.0 and later. It requires the XView toolkit and the OpenWindows window manager (version 2.0 or 3.0). The XView toolkit is distributed with Open Windows. A color monitor is also required. The standard distribution medium for RATIO_TOOL is a .25 inch streaming magnetic tape cartridge in UNIX tar format. An electronic copy of the documentation is included on the program media. RATIO_TOOL was developed in 1992 and is a copyrighted work with all copyright vested in NASA. Sun, SunOS, and OpenWindows are trademarks of Sun Microsystems, Inc. UNIX is a registered trademark of AT&T Bell Laboratories.

  11. Producing Against Poverty

    NARCIS (Netherlands)

    Ypeij, Annelou

    2000-01-01

    Producing against Poverty is an anthropological research on micro-entrepreneurs in Lima, Peru. It analyses the way micro-producers accumulate capital. The anthropological approach of the book starts with an analysis of the daily lives of the micro-producers. Its gender approach makes a comparison

  12. Effects of radiation dose reduction in Volume Perfusion CT imaging of acute ischemic stroke.

    Science.gov (United States)

    Othman, Ahmed E; Brockmann, Carolin; Yang, Zepa; Kim, Changwon; Afat, Saif; Pjontek, Rastislav; Nikobashman, Omid; Brockmann, Marc A; Kim, Jong Hyo; Wiesmann, Martin

    2015-12-01

    To examine the influence of radiation dose reduction on image quality and sensitivity of Volume Perfusion CT (VPCT) maps regarding the detection of ischemic brain lesions. VPCT data of 20 patients with suspected ischemic stroke acquired at 80 kV and 180 mAs were included. Using realistic reduced-dose simulation, low-dose VPCT datasets with 144 mAs, 108 mAs, 72 mAs and 36 mAs (80 %, 60 %, 40 % and 20 % of the original levels) were generated, resulting in a total of 100 datasets. Perfusion maps were created and signal-to-noise-ratio (SNR) measurements were performed. Qualitative analyses were conducted by two blinded readers, who also assessed the presence/absence of ischemic lesions and scored CBV and CBF maps using a modified ASPECTS-score. SNR of all low-dose datasets were significantly lower than those of the original datasets (p < .05). All datasets down to 72 mAs (40 %) yielded sufficient image quality and high sensitivity with excellent inter-observer-agreements, whereas 36 mAs datasets (20 %) yielded poor image quality in 15 % of the cases with lower sensitivity and inter-observer-agreements. Low-dose VPCT using decreased tube currents down to 72 mAs (40 % of original radiation dose) produces sufficient perfusion maps for the detection of ischemic brain lesions. • Perfusion CT is highly accurate for the detection of ischemic brain lesions • Perfusion CT results in high radiation exposure, therefore low-dose protocols are required • Reduction of tube current down to 72 mAs produces sufficient perfusion maps.

  13. Oxygen enhancement ratio (OER) to Neutron and Co-60 γ ray

    International Nuclear Information System (INIS)

    Kim, Mi Sook; Ji, Young Hoon; Lee, Yong Min; Kim Kyeoung Jung

    1997-01-01

    Experiments in vitro, using human cell lines was carried out in order to establish whether or not there was a difference between oxygen enhancement ratio (OER) of neutron and Co-60 γ-ray and to determine OER dependence on radiation dose. MG-63 cell line and H-460 cell line were defined as the most sensitive cell line to neutron among our laboratory holding cell lines through preliminary study. Anoxia as was produced in glove box. The box was flushed for one hour with a mixture of 5 % CO 2 in ultrapure N 2 (total oxygen concentration < 10 ppm) and irradiated with neutron and Co-60 γ-ray. Oxic condition was same as anoxic condition except being irradiated in general air condition. The lower OER was observed in neutron than in Co-60 γ-ray. The dose dependence of OER was observed in neutron and Co-60 γ-ray all. But the dose dependence of the OER is somewhat larger for Co-60 γ-ray than for neutron. In the range of 1 to 8 Gy, the OER for photon and neutron range from 1.54 to 1.94 and 1.23 to 1.26 in MG-63 cell line. In case of H-460 the OER for Co-60 γ-ray and neutron range from 1.24 to 1.60 and 1.06 to 1.07 respectively. (author). 19 refs., 5 tabs., 5 figs

  14. Oxygen enhancement ratio (OER) to Neutron and Co-60 {gamma} ray

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Sook; Ji, Young Hoon; Lee, Yong Min; Kim Kyeoung Jung [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1997-01-01

    Experiments in vitro, using human cell lines was carried out in order to establish whether or not there was a difference between oxygen enhancement ratio (OER) of neutron and Co-60 {gamma}-ray and to determine OER dependence on radiation dose. MG-63 cell line and H-460 cell line were defined as the most sensitive cell line to neutron among our laboratory holding cell lines through preliminary study. Anoxia as was produced in glove box. The box was flushed for one hour with a mixture of 5 % CO{sub 2} in ultrapure N{sub 2} (total oxygen concentration < 10 ppm) and irradiated with neutron and Co-60 {gamma}-ray. Oxic condition was same as anoxic condition except being irradiated in general air condition. The lower OER was observed in neutron than in Co-60 {gamma}-ray. The dose dependence of OER was observed in neutron and Co-60 {gamma}-ray all. But the dose dependence of the OER is somewhat larger for Co-60 {gamma}-ray than for neutron. In the range of 1 to 8 Gy, the OER for photon and neutron range from 1.54 to 1.94 and 1.23 to 1.26 in MG-63 cell line. In case of H-460 the OER for Co-60 {gamma}-ray and neutron range from 1.24 to 1.60 and 1.06 to 1.07 respectively. (author). 19 refs., 5 tabs., 5 figs.

  15. Biological dose estimation

    African Journals Online (AJOL)

    a radiation. •. In exposure. Biological dose estimation involving low-dose. S. JANSEN, G. J. VAN HUYSSTEEN. Summary. Blood specimens were collected from 8 people 18 days after they had been accidentally exposed to a 947,2 GBq iridium-. 192 source during industrial application. The equivalent whole-body dose ...

  16. High ratio recirculating gas compressor

    Science.gov (United States)

    Weinbrecht, J.F.

    1989-08-22

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

  17. PUNISHMENT BY SD ASSOCIATED WITH FIXED-RATIO REINFORCEMENT.

    Science.gov (United States)

    THOMPSON, D M

    1965-05-01

    Two pigeons were trained with positive reinforcement on a multiple FR VI 2 schedule. The VI 2 component was held constant while the FR component was changed from ratios of 1 to 300. After responding had stabilized at each FR value, VI responses produced briefly either the fixed-ratio S(D) or a stimulus uncorrelated with either schedule component. Compared to the effects of the uncorrelated stimulus change, the fixed-ratio S(D) produced a decrease in VI responding proportional to the size of the FR requirement. It is concluded that stimuli associated with high FR schedules served as punishment for the ongoing behavior.

  18. Updated thinking on positivity ratios.

    Science.gov (United States)

    Fredrickson, Barbara L

    2013-12-01

    This article presents my response to the article by Brown, Sokal, and Friedman (2013), which critically examined Losada's conceptual and mathematical work (as presented in Losada, 1999; Losada & Heaphy, 2004; and Fredrickson & Losada; 2005) and concluded that mathematical claims for a critical tipping point positivity ratio are unfounded. In the present article, I draw recent empirical evidence together to support the continued value of computing and seeking to elevate positivity ratios. I also underscore the necessity of modeling nonlinear effects of positivity ratios and, more generally, the value of systems science approaches within affective science and positive psychology. Even when scrubbed of Losada's now-questioned mathematical modeling, ample evidence continues to support the conclusion that, within bounds, higher positivity ratios are predictive of flourishing mental health and other beneficial outcomes. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  19. Evaluation of Alum/Lime Coagulant for the Removal of Turbidity from Al- Ahdab Iraqi Oilfields Produced Water

    Directory of Open Access Journals (Sweden)

    Basma Abbas Abdulmajeed

    2015-07-01

    Full Text Available The removal of turbidity from produced water by chemical coagulation/flocculation method using locally available coagulants was investigated. Aluminum sulfate (alum is selected as a primary coagulant, while calcium hydroxide (lime is used as a coagulant aid. The performance of these coagulants was studied through jar test by comparing turbidity removal at different coagulant/ coagulants aid ratio, coagulant dose, water pH, and sedimentation time. In addition, an attempt has been made to examine the relationship between turbidity (NTU and total suspended solids (mg/L on the same samples of produced water. The best conditions for turbidity removal can be obtained at 75% alum+25% lime coagulant at coagulant dose of 80 mg/l at pH 6 and 120 min for sedimentation time. At these conditions, the turbidity reading was reduced from 92 to 2.1 NTU.

  20. Fluence Correction Factors and Stopping Power Ratios for Clinical Ion Beams

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Hansen, David Christoffer; Sobolevsky, Nikolai

    2011-01-01

    Background. In radiation therapy, the principal dosimetric quantity of interest is the absorbed dose to water. Therefore, a dose conversion to dose to water is required for dose deposited by ion beams in other media. This is in particular necessary for dose measurements in plastic phantoms...... for increased positioning accuracy, graphite calorimetry being developed as a primary standard for dose to water dosimetry, but also for the comparison of dose distributions from Monte Carlo simulations with those of pencil beam algorithms. Material and methods. In the conversion of absorbed dose to phantom...... material to absorbed dose to water the water-to-material stopping power ratios (STPR) and the fluence correction factors (FCF) for the full charged particle spectra are needed. We determined STPR as well as FCF for water to graphite, bone (compact), and PMMA as a function of water equivalent depth, zw...

  1. Energy Balance Bowen Ratio Station (EBBR) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Cook, DR

    2011-02-23

    The energy balance Bowen ratio (EBBR) system produces 30-minute estimates of the vertical fluxes of sensible and latent heat at the local surface. Flux estimates are calculated from observations of net radiation, soil surface heat flux, and the vertical gradients of temperature and relative humidity (RH). Meteorological data collected by the EBBR are used to calculate bulk aerodynamic fluxes, which are used in the Bulk Aerodynamic Technique (BA) EBBR value-added product (VAP) to replace sunrise and sunset spikes in the flux data. A unique aspect of the system is the automatic exchange mechanism (AEM), which helps to reduce errors from instrument offset drift.

  2. Energy Balance Bowen Ratio (EBBR) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Cook, D. R. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-01-01

    The Energy Balance Bowen Ratio (EBBR) system produces 30-minute estimates of the vertical fluxes of sensible and latent heat at the local surface. Flux estimates are calculated from observations of net radiation, soil surface heat flux, and the vertical gradients of temperature and relative humidity (RH). Meteorological data collected by the EBBR are used to calculate bulk aerodynamic fluxes, which are used in the Bulk Aerodynamic Technique (BA) EBBR value-added product (VAP) to replace sunrise and sunset spikes in the flux data. A unique aspect of the system is the automatic exchange mechanism (AEM), which helps to reduce errors from instrument offset drift.

  3. The problem of the population dose

    International Nuclear Information System (INIS)

    Belyaev, V.A.

    1976-08-01

    This report investigates methods of calculating the population dose due to emissions from nuclear reactors. The exposure of the local population is considered as well as the exposure of the population of the remote area where food produced near the reactor site is consumed. Units of measurement for the population dose are discussed. A concrete example is given for calculating the contribution of isotopes of radioactive noble gases, 131 I and 137 Cs. (orig.) [de

  4. SU-F-T-93: Breast Surface Dose Enhancement Using a Clinical Prone Breast Board

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, M; Jozsef, G [New York University Langone Medical Center, New York, NY (United States)

    2016-06-15

    Purpose: The use of specialized patient set-up devices in radiotherapy, such as prone breast boards, may have unwanted dosimetric effects. The goal of this study was to evaluate the effect of a clinically used prone breast board on skin dose due to buildup. Methods: GafChromic film (EBT3) was used for dose measurements on the surface of a solid water phantom shaped to mimic the curvature of the breast. We investigated two setup scenarios: the medial field border placed at the medial edge of the board and 1 cm contralaterally from that edge. A strip of film was taped to the medial surface of the phantom. Gantry angles varied from 10 to 30 degrees below the lateral gantry position, representing anterior oblique fields. The measurements were performed with and without the presence of the board; the ratio of their corresponding doses (dose enhancement) was evaluated. Results: For the cases where the field edge is at the edge of the board, the dose enhancement is negligible for all the tested angles. When the field edge is 1 cm inside the board, the maximum surface dose enhancement varies depending on the gantry angle between 2.2 for 30 degrees and 3.2 for 20 degrees. The length on the film at which the presence of the board is detectable (i.e. where there is dose enhancement) is longer for the shallower angles. Conclusion: Even the low-density, thin carbon fiber board with a thin soft foam pad on the top can produce significant dose enhancement on the skin in prone breast treatment due to loss of buildup. However, it happens only when the patient mid-sternum is over the board, i.e. the medial edge of the field traverses through the board and pad. Even then, the effect occurs only at the field edge, i.e. the penumbral region.

  5. Concrete produced with recycled aggregates

    Directory of Open Access Journals (Sweden)

    J. J. L. Tenório

    Full Text Available This paper presents the analysis of the mechanical and durable properties of recycled aggregate concrete (RAC for using in concrete. The porosity of recycled coarse aggregates is known to influence the fresh and hardened concrete properties and these properties are related to the specific mass of the recycled coarse aggregates, which directly influences the mechanical properties of the concrete. The recycled aggregates were obtained from construction and demolition wastes (CDW, which were divided into recycled sand (fine and coarse aggregates. Besides this, a recycled coarse aggregate of a specific mass with a greater density was obtained by mixing the recycled aggregates of the CDW with the recycled aggregates of concrete wastes (CW. The concrete was produced in laboratory by combining three water-cement ratios, the ratios were used in agreement with NBR 6118 for structural concretes, with each recycled coarse aggregates and recycled sand or river sand, and the reference concrete was produced with natural aggregates. It was observed that recycled aggregates can be used in concrete with properties for structural concrete. In general, the use of recycled coarse aggregate in combination with recycled sand did not provide good results; but when the less porous was used, or the recycled coarse aggregate of a specific mass with a greater density, the properties of the concrete showed better results. Some RAC reached bigger strengths than the reference concrete.

  6. Six steps to a successful dose-reduction strategy

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, M. [Rolls-Royce & Associates Ltd., Derby (United Kingdom)

    1995-03-01

    The increased importance of demonstrating achievement of the ALARA principle has helped produce a proliferation of dose-reduction ideas. Across a company there may be many dose-reduction items being pursued in a variety of areas. However, companies have a limited amount of resource and, therefore, to ensure funding is directed to those items which will produce the most benefit and that all areas apply a common policy, requires the presence of a dose-reduction strategy. Six steps were identified in formulating the dose-reduction strategy for Rolls-Royce and Associates (RRA): (1) collating the ideas; (2) quantitatively evaluating them on a common basis; (3) prioritizing the ideas in terms of cost benefit, (4) implementation of the highest priority items; (5) monitoring their success; (6) periodically reviewing the strategy. Inherent in producing the dose-reduction strategy has been a comprehensive dose database and the RRA-developed dose management computer code DOMAIN, which allows prediction of dose rates and dose. The database enabled high task dose items to be identified, assisted in evaluating dose benefits, and monitored dose trends once items had been implemented. The DOMAIN code was used both in quantifying some of the project dose benefits and its results, such as dose contours, used in some of the dose-reduction items themselves. In all, over fifty dose-reduction items were evaluated in the strategy process and the items which will give greatest benefit are being implemented. The strategy has been successful in giving renewed impetus and direction to dose-reduction management.

  7. Six steps to a successful dose-reduction strategy

    International Nuclear Information System (INIS)

    Bennett, M.

    1995-01-01

    The increased importance of demonstrating achievement of the ALARA principle has helped produce a proliferation of dose-reduction ideas. Across a company there may be many dose-reduction items being pursued in a variety of areas. However, companies have a limited amount of resource and, therefore, to ensure funding is directed to those items which will produce the most benefit and that all areas apply a common policy, requires the presence of a dose-reduction strategy. Six steps were identified in formulating the dose-reduction strategy for Rolls-Royce and Associates (RRA): (1) collating the ideas; (2) quantitatively evaluating them on a common basis; (3) prioritizing the ideas in terms of cost benefit, (4) implementation of the highest priority items; (5) monitoring their success; (6) periodically reviewing the strategy. Inherent in producing the dose-reduction strategy has been a comprehensive dose database and the RRA-developed dose management computer code DOMAIN, which allows prediction of dose rates and dose. The database enabled high task dose items to be identified, assisted in evaluating dose benefits, and monitored dose trends once items had been implemented. The DOMAIN code was used both in quantifying some of the project dose benefits and its results, such as dose contours, used in some of the dose-reduction items themselves. In all, over fifty dose-reduction items were evaluated in the strategy process and the items which will give greatest benefit are being implemented. The strategy has been successful in giving renewed impetus and direction to dose-reduction management

  8. Characteristics of repair following very low doses

    International Nuclear Information System (INIS)

    Braby, L.A.; Metting, N.F.; Nelson, J.M.

    1987-01-01

    The effects of ionizing radiation on living systems being with the physical processes of energy deposition and develop through many stages of chemical reaction and biological response. The modeling effort attempts to organize the available data and theories of all of these stages into self-consistent models that can be compared and tested. In some cases, important differences among models result in only small differences in cell survival within the ranges of dose and dose rate that are normally investigated. To overcome this limitation, new ways of irradiating cells at extremes of dose rate, or ways of evaluating the effects of very small doses, are developed. Mathematical modeling and cellular studies complement each other. It has recently been found that some mechanisms are not adequate to account for the interaction of dose and repair time as they affect the reproductive survival of plateau-phase Chinese hamster ovary (CHO) cells. Repair of radiation-induced cellular damage plays a central role in the survival of cells exposed to doses of 1 Gy or more. This repair is responsible for the dose rate, split-dose and delayed plating effect and can be evaluated. Because split-dose and dose-rate experiments involve repair during irradiation and delayed plating experiments involve repair after irradiation is completed, it was originally thought that different repair processes were involved. It is now clear that this is not necessarily the case. Appropriately designed models can account for observed effects at conventional doses (1 Gy or more) whether they assume all damage is lethal unless repaired or some damage is innocuous unless it interacts with additional damage. The fact that the survival following a plating delay is always less than the survival following immediate plating at low doses indicates that the damage produced is probably not potentially lethal

  9. Enjebi Island dose assessment

    International Nuclear Information System (INIS)

    Robison, W.L.; Conrado, C.L.; Phillips, W.A.

    1987-07-01

    We have updeated the radiological dose assessment for Enjebi Island at Enewetak Atoll using data derived from analysis of food crops grown on Enjebi. This is a much more precise assessment of potential doses to people resettling Enjebi Island than the 1980 assessment in which there were no data available from food crops on Enjebi. Details of the methods and data used to evaluate each exposure pathway are presented. The terrestrial food chain is the most significant potential exposure pathway and 137 Cs is the radionuclide responsible for most of the estimated dose over the next 50 y. The doses are calculated assuming a resettlement date of 1990. The average wholebody maximum annual estimated dose equivalent derived using our diet model is 166 mremy;the effective dose equivalent is 169 mremy. The estimated 30-, 50-, and 70-y integral whole-body dose equivalents are 3.5 rem, 5.1 rem, and 6.2 rem, respectively. Bone-marrow dose equivalents are only slightly higher than the whole-body estimates in each case. The bone-surface cells (endosteal cells) receive the highest dose, but they are a less sensitive cell population and are less sensitive to fatal cancer induction than whole body and bone marrow. The effective dose equivalents for 30, 50, and 70 y are 3.6 rem, 5.3 rem, and 6.6 rem, respectively. 79 refs., 17 figs., 24 tabs

  10. Biologically produced sulfur

    NARCIS (Netherlands)

    Kleinjan, W.E.; Keizer, de A.; Janssen, A.J.H.

    2003-01-01

    Sulfur compound oxidizing bacteria produce sulfur as an intermediate in the oxidation of hydrogen sulfide to sulfate. Sulfur produced by these microorganisms can be stored in sulfur globules, located either inside or outside the cell. Excreted sulfur globules are colloidal particles which are

  11. Consumers and Producers

    NARCIS (Netherlands)

    E. Maira (Elisa)

    2018-01-01

    markdownabstractIn the last few decades, advances in information and communication technology have dramatically changed the way consumers and producers interact in the marketplace. The Internet and social media have torn down the information barrier between producers and consumers, leading to

  12. Fungi producing significant mycotoxins.

    Science.gov (United States)

    2012-01-01

    Mycotoxins are secondary metabolites of microfungi that are known to cause sickness or death in humans or animals. Although many such toxic metabolites are known, it is generally agreed that only a few are significant in causing disease: aflatoxins, fumonisins, ochratoxin A, deoxynivalenol, zearalenone, and ergot alkaloids. These toxins are produced by just a few species from the common genera Aspergillus, Penicillium, Fusarium, and Claviceps. All Aspergillus and Penicillium species either are commensals, growing in crops without obvious signs of pathogenicity, or invade crops after harvest and produce toxins during drying and storage. In contrast, the important Fusarium and Claviceps species infect crops before harvest. The most important Aspergillus species, occurring in warmer climates, are A. flavus and A. parasiticus, which produce aflatoxins in maize, groundnuts, tree nuts, and, less frequently, other commodities. The main ochratoxin A producers, A. ochraceus and A. carbonarius, commonly occur in grapes, dried vine fruits, wine, and coffee. Penicillium verrucosum also produces ochratoxin A but occurs only in cool temperate climates, where it infects small grains. F. verticillioides is ubiquitous in maize, with an endophytic nature, and produces fumonisins, which are generally more prevalent when crops are under drought stress or suffer excessive insect damage. It has recently been shown that Aspergillus niger also produces fumonisins, and several commodities may be affected. F. graminearum, which is the major producer of deoxynivalenol and zearalenone, is pathogenic on maize, wheat, and barley and produces these toxins whenever it infects these grains before harvest. Also included is a short section on Claviceps purpurea, which produces sclerotia among the seeds in grasses, including wheat, barley, and triticale. The main thrust of the chapter contains information on the identification of these fungi and their morphological characteristics, as well as factors

  13. Registration of radiation doses

    International Nuclear Information System (INIS)

    2000-02-01

    In Finland the Radiation and Nuclear Safety Authority (STUK) is maintaining the register (called Dose Register) of the radiation exposure of occupationally exposed workers in order to ensure compliance with the principles of optimisation and individual protection. The guide contains a description of the Dose Register and specifies the responsibilities of the party running a radiation practice to report the relevant information to the Dose Register

  14. Dose computation for therapeutic electron beams

    Science.gov (United States)

    Glegg, Martin Mackenzie

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

  15. Transplantation Dose Alters the Differentiation Program of Hematopoietic Stem Cells.

    Science.gov (United States)

    Brewer, Casey; Chu, Elizabeth; Chin, Mike; Lu, Rong

    2016-05-24

    Hematopoietic stem cell (HSC) transplantation is the most prevalent stem cell therapy, but it remains a risky procedure. To improve this treatment, it is important to understand how transplanted stem cells rebuild the blood and immune systems and how this process is impacted by transplantation variables such as the HSC dose. Here, we find that, in the long term following transplantation, 70%-80% of donor-HSC-derived clones do not produce all measured blood cell types. High HSC doses lead to more clones that exhibit balanced lymphocyte production, whereas low doses produce more T-cell-specialized clones. High HSC doses also produce significantly higher proportions of early-differentiating clones compared to low doses. These complex differentiation behaviors uncover the clonal-level regeneration dynamics of hematopoietic regeneration and suggest that transplantation dose can be exploited to improve stem cell therapy. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  16. Doses from portable gauges

    International Nuclear Information System (INIS)

    Linauskas, S.H.

    1988-08-01

    Field studies to measure actual radiation exposures of operators of commercial moisture-density gauges were undertaken in several regions of Canada. Newly developed bubble detector dosimeter technology and conventional dosimetry such as thermoluminescent dosimeters (TLDs), integrating electronic dosimeters (DRDs), and CR-39 neutron track-etch detectors were used to estimate the doses received by 23 moisture-density gauge operators and maintenance staff. These radiation dose estimates were supported by mapping radiation fields and accounting for the time an operator was near a gauge. Major findings indicate that gauge maintenance and servicing workers were more likely than gauge operators to receive exposures above the level of 5 mSv, and that neutron doses were roughly the same as gamma doses. Gauge operators receive approximately 75% of their dose when transporting and carrying the gauge. Dose to their hands is similar to the dose to their trunks, but the dose to their feet area is 6 to 30 times higher. Gamma radiation is the primary source of radiation contributing to operator dose

  17. Paediatric dose display

    International Nuclear Information System (INIS)

    Griffin, D.W.; Derges, S.; Hesslewood, S.

    1984-01-01

    A compact, inexpensive unit, based on an 8085 microprocessor, has been designed for calculating doses of intravenous radioactive injections for children. It has been used successfully for over a year. The dose is calculated from the body surface area and the result displayed in MBq. The operator can obtain the required dose on a twelve character alphanumeric display by entering the age of the patient and the adult dose using a hexadecimal keyboard. Circuit description, memory map and input/output, and firmware are dealt with. (U.K.)

  18. Rotator Cuff Strength Ratio and Injury in Glovebox Workers

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Amelia M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-30

    Rotator cuff integrity is critical to shoulder health. Due to the high workload imposed upon the shoulder while working in an industrial glovebox, this study investigated the strength ratio of the rotator cuff muscles in glovebox workers and compared this ratio to the healthy norm. Descriptive statistics were collected using a short questionnaire. Handheld dynamometry was used to quantify the ratio of forces produced in the motions of shoulder internal and external rotation. Results showed this population to have shoulder strength ratios that were significantly different from the healthy norm. The deviation from the normal ratio demonstrates the need for solutions designed to reduce the workload on the rotator cuff musculature of glovebox workers in order to improve health and safety. Assessment of strength ratios can be used to screen for risk of symptom development.

  19. Small populations and offspring sex-ratio deviations in eagles.

    Science.gov (United States)

    Ferrer, Miguel; Newton, Ian; Pandolfi, Massimo

    2009-08-01

    Stochastic variation of sex ratio has long been appreciated as a potential factor driving small populations to extinction, but it is not the only source of sex-ratio bias in small populations. We examined whether some consequences of sex allocation could affect extinction risk in small populations of size-dimorphic birds such as eagles. We report variations in sex ratio at fledging from a long-term study of a declining population of Spanish Imperial Eagles (Aquila adalberti). Nestling sex-ratio deviation apparently was mediated by age of breeders, whereas territory quality had no obvious effect. Adult-adult pairs produced the same proportion of both sexes in high- or low-density situations, but pairs with at least one member in nonadult plumage class produced more males. As the population declined over a period of years, the proportion of breeders with immature plumage increased; consequently, the proportion of fledgling males increased. However, when population density was high, the proportion of breeders with immature plumage decreased and more female offspring were produced. This relationship between population density, composition of breeder age, and fledgling sex ratios allowed us to make predictions of extinction risk due to nonstochastic deviations of sex ratio in small, declining populations. In the study population, on the basis of the Vortex simulation results, an estimated reduction of 42.5% in predicted mean time to extinction was attributed solely to biased sex ratio.

  20. Feasibility study on an integrated AEC-grid device for the optimization of image quality and exposure dose in mammography

    Science.gov (United States)

    Kim, Kyo-Tae; Yun, Ryang-Young; Han, Moo-Jae; Heo, Ye-Ji; Song, Yong-Keun; Heo, Sung-Wook; Oh, Kyeong-Min; Park, Sung-Kwang

    2017-10-01

    Currently, in the radiation diagnosis field, mammography is used for the early detection of breast cancer. In addition, studies are being conducted on a grid to produce high-quality images. Although the grid ratio of the grid, which affects the scattering removal rate, must be increased to improve image quality, it increases the total exposure dose. While the use of automatic exposure control is recommended to minimize this problem, existing mammography equipment, unlike general radiography equipment, is mounted on the back of a detector. Therefore, the device is greatly affected by the detector and supporting device, and it is difficult to control the exposure dose. Accordingly, in this research, an integrated AEC-grid device that simultaneously performs AEC and grid functions was used to minimize the unnecessary exposure dose while removing scattering, thereby realizing superior image quality.

  1. Ratio Bias and Policy Preferences

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Tue

    2016-01-01

    Numbers permeate modern political communication. While current scholarship on framing effects has focused on the persuasive effects of words and arguments, this article shows that framing of numbers can also substantially affect policy preferences. Such effects are caused by ratio bias, which...

  2. Gender Ratios for Reading Difficulties

    Science.gov (United States)

    Hawke, Jesse L.; Olson, Richard K.; Willcut, Erik G.; Wadsworth, Sally J.; DeFries, John C.

    2009-01-01

    The prevalence of reading difficulties is typically higher in males than females in both referred and research-identified samples, and the ratio of males to females is greater in more affected samples. To explore possible gender differences in reading performance, we analysed data from 1133 twin pairs in which at least one member of each pair had…

  3. Agricultural Producer Certificates

    Data.gov (United States)

    Montgomery County of Maryland — A Certified Agricultural Producer, or representative thereof, is an individual who wishes to sell regionally-grown products in the public right-of-way. A Certified...

  4. Sex ratios of Mountain Plovers from egg production to fledging

    Directory of Open Access Journals (Sweden)

    Margaret M. Riordan

    2015-12-01

    Full Text Available Skewed sex ratios can have negative implications for population growth if they do not match a species' life history. A skewed tertiary sex ratio has been detected in a population of Mountain Plover (Charadrius montanus, a grassland shorebird experiencing population declines. To study the cause of the observed male skew, we examined three early life stages between egg and fledgling in eastern Colorado from 2010 to 2012. This allows us to distinguish between egg production and chick survival as an explanation for the observed skew. We examined the primary sex ratio in eggs produced and the secondary sex ratio in hatched chicks to see if the sex ratio bias occurs before hatching. We also determined the sex ratio at fledging to reveal sex-specific mortality of nestlings. The primary sex ratio was 1.01 (± 0.01 males per female. The secondary sex ratio consisted of 1.10 (± 0.02 males per female. The probability of a chick surviving to fledging differed between males (0.55 ± 0.13 and females (0.47 ± 0.15, but the precision of these survival estimates was low. Sex ratios in early life stages of the Mountain Plover do not explain the skewed sex ratio observed in adults in this breeding population.

  5. Occupational dose constraint

    International Nuclear Information System (INIS)

    Heilbron Filho, Paulo Fernando Lavalle; Xavier, Ana Maria

    2005-01-01

    The revision process of the international radiological protection regulations has resulted in the adoption of new concepts, such as practice, intervention, avoidable and restriction of dose (dose constraint). The latter deserving of special mention since it may involve reducing a priori of the dose limits established both for the public and to individuals occupationally exposed, values that can be further reduced, depending on the application of the principle of optimization. This article aims to present, with clarity, from the criteria adopted to define dose constraint values to the public, a methodology to establish the dose constraint values for occupationally exposed individuals, as well as an example of the application of this methodology to the practice of industrial radiography

  6. Surface dose extrapolation measurements with radiographic film

    International Nuclear Information System (INIS)

    Butson, Martin J; Cheung Tsang; Yu, Peter K N; Currie, Michael

    2004-01-01

    Assessment of surface dose delivered from radiotherapy x-ray beams for optimal results should be performed both inside and outside the prescribed treatment fields. An extrapolation technique can be used with radiographic film to perform surface dose assessment for open field high energy x-ray beams. This can produce an accurate two-dimensional map of surface dose if required. Results have shown that the surface percentage dose can be estimated within ±3% of parallel plate ionization chamber results with radiographic film using a series of film layers to produce an extrapolated result. Extrapolated percentage dose assessment for 10 cm, 20 cm and 30 cm square fields was estimated to be 15% ± 2%, 29% ± 3% and 38% ± 3% at the central axis and relatively uniform across the treatment field. The corresponding parallel plate ionization chamber measurements are 16%, 27% and 37%, respectively. Surface doses are also measured outside the treatment field which are mainly due to scattered electron contamination. To achieve this result, film calibration curves must be irradiated to similar x-ray field sizes as the experimental film to minimize quantitative variations in film optical density caused by varying x-ray spectrum with field size. (note)

  7. Survey of literature on dispersion ratio and collection ratio of radioisotopes in animal study using radioisotopes

    International Nuclear Information System (INIS)

    Tozuka, Zenzaburo; Doi, Masahiro; Miyazawa, Eiji; Kawakami, Takeo

    1998-01-01

    A survey of literature in the title was performed to know the actual status of the dispersion from excretion and expiration studies of radioisotopes since, at present, the probable dispersion ratio is assumed to be 100% in calculation for legally permitted use of radioisotopes which conceivably being far from the real status and being incompatible with the guideline for pharmacokinetic studies requiring the recovery of >95% of dosed radioactivity in balance study. There are two interpretations for the dispersion; it is the expiration ratio and it is the fraction unrecovered. Survey was done on 11 Japanese and foreign journals in 1985-1996 publishing most of pharmacokinetic studies and on 650 compounds in 358 facilities with 1,975 experiments in total. In those experiments, the total recovery of radioactivity was 95% in average, unrecovered fraction, 5% and expiration ratio, 2%. As for unclide, 14 C, 3 H, 125 I and 35 S were surveyed since they occupied 99.4% of the experiments and their dispersion was <5%. Rats were used in 70% of the experiments and the dispersion in all animal experiments was about 5%. Administration route was regardless of the dispersion. (K.H.)

  8. Use of a range scaling method to determine alanine/water stopping power ratios

    International Nuclear Information System (INIS)

    McEwen, M.R.; Sephton, J.P.; Sharpe, P.H.G.; Shipley, D.R.

    2003-01-01

    A phantom composed of alanine dosimeter material has been constructed and depth-dose measurements made in a 10 MeV electron beam. The results have demonstrated the feasibility of using relative depth-dose measurements to determine stopping power ratios in materials of dosimetric interest. Experimental stopping power ratios for alanine dosimeter material and water agreed with the data of ICRU Report 37 within the uncertainty of the experiment (±1.2% at a 95% confidence level)

  9. Effect of dosimeter type for commissioning small photon beams on calculated dose distribution in stereotactic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    García-Garduño, O. A., E-mail: oagarciag@innn.edu.mx, E-mail: amanda.garcia.g@gmail.com [Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía, Mexico City 14269, México and Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, Legaria 694, México City 11500, México (Mexico); Rodríguez-Ponce, M. [Departamento de Biofísica, Instituto Nacional de Cancerología, Mexico City 14080, México (Mexico); Gamboa-deBuen, I. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510 (Mexico); Rodríguez-Villafuerte, M. [Instituto de Física, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City 04510 (Mexico); Galván de la Cruz, O. O. [Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía, Mexico City 14269, México (Mexico); and others

    2014-09-15

    Purpose: To assess the impact of the detector used to commission small photon beams on the calculated dose distribution in stereotactic radiosurgery (SRS). Methods: In this study, six types of detectors were used to characterize small photon beams: three diodes [a silicon stereotactic field diode SFD, a silicon diode SRS, and a silicon diode E], an ionization chamber CC01, and two types of radiochromic film models EBT and EBT2. These detectors were used to characterize circular collimated beams that were generated by a Novalis linear accelerator. This study was conducted in two parts. First, the following dosimetric data, which are of particular interest in SRS, were compared for the different detectors: the total scatter factor (TSF), the tissue phantom ratios (TPRs), and the off-axis ratios (OARs). Second, the commissioned data sets were incorporated into the treatment planning system (TPS) to compare the calculated dose distributions and the dose volume histograms (DVHs) that were obtained using the different detectors. Results: The TSFs data measured by all of the detectors were in good agreement with each other within the respective statistical uncertainties: two exceptions, where the data were systematically below those obtained for the other detectors, were the CC01 results for all of the circular collimators and the EBT2 film results for circular collimators with diameters below 10.0 mm. The OAR results obtained for all of the detectors were in excellent agreement for all of the circular collimators. This observation was supported by the gamma-index test. The largest difference in the TPR data was found for the 4.0 mm circular collimator, followed by the 10.0 and 20.0 mm circular collimators. The results for the calculated dose distributions showed that all of the detectors passed the gamma-index test at 100% for the 3 mm/3% criteria. The aforementioned observation was true regardless of the size of the calculation grid for all of the circular collimators

  10. Evidence for Dose-Additive Effects of Pyrethroids on Motor Activity in Rats

    Science.gov (United States)

    Wolansky, Marcelo J.; Gennings, Chris; DeVito, Michael J.; Crofton, Kevin M.

    2009-01-01

    Background Pyrethroids are neurotoxic insecticides used in a variety of indoor and outdoor applications. Previous research characterized the acute dose–effect functions for 11 pyrethroids administered orally in corn oil (1 mL/kg) based on assessment of motor activity. Objectives We used a mixture of these 11 pyrethroids and the same testing paradigm used in single-compound assays to test the hypothesis that cumulative neurotoxic effects of pyrethroid mixtures can be predicted using the default dose–addition theory. Methods Mixing ratios of the 11 pyrethroids in the tested mixture were based on the ED30 (effective dose that produces a 30% decrease in response) of the individual chemical (i.e., the mixture comprised equipotent amounts of each pyrethroid). The highest concentration of each individual chemical in the mixture was less than the threshold for inducing behavioral effects. Adult male rats received acute oral exposure to corn oil (control) or dilutions of the stock mixture solution. The mixture of 11 pyrethroids was administered either simultaneously (2 hr before testing) or after a sequence based on times of peak effect for the individual chemicals (4, 2, and 1 hr before testing). A threshold additivity model was fit to the single-chemical data to predict the theoretical dose–effect relationship for the mixture under the assumption of dose additivity. Results When subthreshold doses of individual chemicals were combined in the mixtures, we found significant dose-related decreases in motor activity. Further, we found no departure from the predicted dose-additive curve regardless of the mixture dosing protocol used. Conclusion In this article we present the first in vivo evidence on pyrethroid cumulative effects supporting the default assumption of dose addition. PMID:20019907

  11. Ultra-low-dose naltrexone reduces the rewarding potency of oxycodone and relapse vulnerability in rats.

    Science.gov (United States)

    Leri, Francesco; Burns, Lindsay H

    2005-10-01

    Ultra-low-dose opioid antagonists have been shown to enhance opioid analgesia and alleviate opioid tolerance and dependence. Our present studies in male Sprague-Dawley rats assessed the abuse potential of oxycodone+ultra-low-dose naltrexone (NTX) versus oxycodone alone. The lowest NTX dose (1 pg/kg/infusion), but not slightly higher doses (10 and 100 pg/kg/infusion), enhanced oxycodone (0.1 mg/kg/infusion) intravenous self-administration, suggesting a reduced rewarding potency per infusion. During tests of reinstatement performed in extinction conditions, co-self-administration of any of these three NTX doses significantly reduced drug-seeking precipitated by priming injections of oxycodone (0.25 mg/kg, s.c.), a drug-conditioned cue, or foot-shock stress. During self-administration on a progressive-ratio schedule, animals self-administering oxycodone (0.1 mg/kg/infusion)+NTX (1 pg/kg/infusion) reached a "break-point" sooner and showed a trend toward less responding compared to rats self-administering oxycodone alone (0.1 mg/kg/infusion). In the final experiment, the addition of ultra-low-dose NTX (10 pg/kg, s.c.) enhanced the acute stimulatory effect of oxycodone (1 mg/kg, s.c.), as well as locomotor sensitization produced by repeated oxycodone administration (7 x 1 mg/kg, s.c.). In summary, this work shows that ultra-low-dose NTX co-treatment augments the locomotor effects of oxycodone as it enhances opioid analgesia, but reduces oxycodone's rewarding potency and subsequent vulnerability to relapse.

  12. Dose response relationship at low doses

    International Nuclear Information System (INIS)

    Schull, W.J.

    1992-01-01

    The data that have accrued in Hiroshima and Nagasaki on the effects of ionizing radiation on the developing human brain are reviewed. Effects considered are severe mental retardation, lowered IQ scores, decline in school performance, seizures, other neuropsychological effects, and small head size. All these factors may be related to radiation doses received by the mother during pregnancy. (L.L.) 3 figs., tab., 7 refs

  13. Noise of Embedded High Aspect Ratio Nozzles

    Science.gov (United States)

    Bridges, James E.

    2011-01-01

    A family of high aspect ratio nozzles were designed to provide a parametric database of canonical embedded propulsion concepts. Nozzle throat geometries with aspect ratios of 2:1, 4:1, and 8:1 were chosen, all with convergent nozzle areas. The transition from the typical round duct to the rectangular nozzle was designed very carefully to produce a flow at the nozzle exit that was uniform and free from swirl. Once the basic rectangular nozzles were designed, external features common to embedded propulsion systems were added: extended lower lip (a.k.a. bevel, aft deck), differing sidewalls, and chevrons. For the latter detailed Reynolds-averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) simulations were made to predict the thrust performance and to optimize parameters such as bevel length, and chevron penetration and azimuthal curvature. Seventeen of these nozzles were fabricated at a scale providing a 2.13 inch diameter equivalent area throat." ! The seventeen nozzles were tested for far-field noise and a few data were presented here on the effect of aspect ratio, bevel length, and chevron count and penetration. The sound field of the 2:1 aspect ratio rectangular jet was very nearly axisymmetric, but the 4:1 and 8:1 were not, the noise on their minor axes being louder than the major axes. Adding bevel length increased the noise of these nozzles, especially on their minor axes, both toward the long and short sides of the beveled nozzle. Chevrons were only added to the 2:1 rectangular jet. Adding 4 chevrons per wide side produced some decrease at aft angles, but increased the high frequency noise at right angles to the jet flow. This trend increased with increasing chevron penetration. Doubling the number of chevrons while maintaining their penetration decreased these effects. Empirical models of the parametric effect of these nozzles were constructed and quantify the trends stated above." Because it is the objective of the Supersonics Project that

  14. Depth absorbed dose distributions for electrons

    International Nuclear Information System (INIS)

    Fregene, A.O.

    1980-01-01

    There is controversy over the comparative depth dose distributions produced by 10 MeV microtron and linear accelerator electron beams. The arguments produced by Brahme and Svensson in their rejection of silicon diode and LiF depth dose measurements (1976, Phys. Med. Biol., vol. 21, 304; 1978, Phys. Med. Biol., vol. 23, 788) have been shown to be insubstantial. These depth dose measurements in fact confirm that the two types of electron beam are not significantly different at 10 MeV. The significant differences originally reported by Brahme et al. on the basis of liquid ionisation chamber measurements (Brahme, A., Hulten, G., and Svensson, H., 1975, Phys. Med. Biol., vol. 20, 39), and the implied clinical advantage of the microtron, therefore both remain in doubt. (UK)

  15. [Sex ratio in Down syndrome].

    Science.gov (United States)

    Kovaleva, N V

    2002-01-01

    Data from 55 publications providing the sex ratio (SR), i.e. ratio between male and female cases of Down syndrome (DS), are presented. In general, SR was skewed toward an excess of males in the majority of studied populations, either in populations with a high level of cases ascertainment (epidemiological studies) or in selected groups. No significant correlation involving the age of either patients or mothers was found. Some other factors which might influence the sex ratio in DS at birth are mentioned. Meta-analysis of data from epidemiological studies suggests the phenomenon is not restricted to free trisomy 21 alone but appears in translocation cases, both in mutant and inherited translocation carriers (SR = 1.31 and 1.36, respectively). In contrast to nonmosaic 47, +21 cases, where SR is close to 1.3, an excess of females was observed in mosaics 46/47, +21 (SR = 0.83). No male predominance was found among patients with DS not tested cytogenetically (SR = 0.98), which may be explained by female predominance in false-positive cases. In populations with a fraction of clinically diagnosed cases of 30% and over, SR has intermediate value of 1.1. The ratio showed a tendency to increase since 1940's, reaching a mean value of 1.35 in 1980's varying from 1.3 to 1.62 in different populations), which might be a consequence of the growing use of karyotyping to confirm diagnosis and of a real increase in proportion of males. In the 1990's, the ratio fell to 1.22 varying from 1.03 to 1.27. As SR is assumed to reflect a proportion of paternal contribution, the discrepancy between the proportions of paternal errors in cytogenetic studies on parental origin of the extra chromosome (24% in the 1980's) and in molecular studies (5-10% in the 1990's) discussed in the literature might be explained by temporal changes alone. Genetic mechanisms of male predominance in trisomy 21 are reviewed, among them models for joint segregation of chromosome 21 and Y chromosome in spermatogenesis

  16. Factors affecting patient dose in diagnostic radiology

    International Nuclear Information System (INIS)

    Poletti, J.L.

    1985-01-01

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

  17. Calculation of committed dose equivalent from intake of tritiated water

    International Nuclear Information System (INIS)

    Law, D.V.

    1978-08-01

    A new computerized method of calculating the committed dose equivalent from the intake of tritiated water at Harwell is described in this report. The computer program has been designed to deal with a variety of intake patterns and urine sampling schemes, as well as to produce committed dose equivalents corresponding to any periods for which individual monitoring for external radiation is undertaken. Details of retrospective doses are added semi-automatically to the Radiation Dose Records and committed dose equivalents are retained on a separate file. (author)

  18. Comparison of twice-daily vs once-daily deferasirox dosing in a gerbil model of iron cardiomyopathy

    Science.gov (United States)

    Otto-Duessel, Maya; Aguilar, Michelle; Nick, Hanspeter; Moats, Rex; Wood, John C.

    2010-01-01

    Objective Despite the availability of deferoxamine chelation therapy for more than 20 years, iron cardiomyopathy remains the leading cause of death in thalassemia major patients. Effective chelation of cardiac iron is difficult; cardiac iron stores respond more slowly to chelation therapy and require a constant gradient of labile iron species between serum and myocytes. We have previously demonstrated the efficacy of once-daily deferasirox in removing previously stored cardiac iron in the gerbil, but changes in cardiac iron were relatively modest compared with hepatic iron. We postulated that daily divided dosing, by sustaining a longer labile iron gradient from myocytes to serum, would produce better cardiac iron chelation than a comparable daily dose. Methods Twenty-four 8- to 10-week-old female gerbils underwent iron dextran—loading for 10 weeks, followed by a 1-week iron equilibration period. Animals were divided into three treatment groups of eight animals each and were treated with deferasirox 100 mg/kg/day as a single dose, deferasirox 100 mg/kg/day daily divided dose, or sham chelation for a total of 12 weeks. Following euthanasia, organs were harvested for quantitative iron and tissue histology. Results Hepatic and cardiac iron contents were not statistically different between the daily single-dose and daily divided-dose groups. However, the ratio of cardiac to hepatic iron content was lower in the divided-dose group (0.78% vs 1.11%, p = 0.0007). Conclusion Daily divided dosing of deferasirox changes the relative cardiac and liver iron chelation profile compared with daily single dosing, trading improvements in cardiac iron elimination for less-effective hepatic chelation. PMID:17588475

  19. Characterization of the exradin A18 chamber ionization according to the IEC70631 standards. This work aims at the characterization of the Exradin model (Standard Imaging) A18 ionization chamber, according to the international standard IEC 607311. Intends to use the camera Exradin A18 for the quality control of a linear accelerator VARIAN model TrueBeam with capacity to produce beams of photons of high energy, unfiltered flatter (in later FFF) with high dose absorbed by pulse rate, why is verified, according to the mentioned standard IEC 60731, even under conditions of high dose absorbed by pulse rate, the efficiency of ion collection from this camera is within tolerances; Caracterizacion de la camara de ionizacion exradin A18 segun el estandar IEC70631. Estudio para haces de fotones sin filtro aplanador

    Energy Technology Data Exchange (ETDEWEB)

    Onses Segarra, A.; Puxeu Vaque, J.; Sancho Kolster, I.; Lizuain Arroyo, M. C.; Picon Olmos, C.

    2013-07-01

    This work aims at the characterization of the Exradin model (Standard Imaging) A18 ionization chamber, according to the international standard IEC 607311. Intends to use the camera Exradin A18 for the quality control of a linear accelerator VARIAN model TrueBeam with capacity to produce beams of photons of high energy, unfiltered flatter (in later FFF) with high dose absorbed by pulse rate, why is verified, according to the mentioned standard IEC 60731, even under conditions of high dose absorbed by pulse rate, the efficiency of ion collection from this camera is within tolerances. (Author)

  20. DOZIM - evaluation dose code for nuclear accident

    International Nuclear Information System (INIS)

    Oprea, I.; Musat, D.; Ionita, I.

    2008-01-01

    During a nuclear accident an environmentally significant fission products release can happen. In that case it is not possible to determine precisely the air fission products concentration and, consequently, the estimated doses will be affected by certain errors. The stringent requirement to cope with a nuclear accident, even minor, imposes creation of a computation method for emergency dosimetric evaluations needed to compare the measurement data to certain reference levels, previously established. These comparisons will allow a qualified option regarding the necessary actions to diminish the accident effects. DOZIM code estimates the soil contamination and the irradiation doses produced either by radioactive plume or by soil contamination. Irradiations either on whole body or on certain organs, as well as internal contamination doses produced by isotope inhalation during radioactive plume crossing are taken into account. The calculus does not consider neither the internal contamination produced by contaminated food consumption, or that produced by radioactive deposits resuspension. The code is recommended for dose computation on the wind direction, at distances from 10 2 to 2 x 10 4 m. The DOZIM code was utilized for three different cases: - In air TRIGA-SSR fuel bundle destruction with different input data for fission products fractions released into the environment; - Chernobyl-like accident doses estimation; - Intervention areas determination for a hypothetical severe accident at Cernavoda Nuclear Power Plant. For the first case input data and results (for a 60 m emission height without iodine retention on active coal filters) are presented. To summarize, the DOZIM code conception allows the dose estimation for any nuclear accident. Fission products inventory, released fractions, emission conditions, atmospherical and geographical parameters are the input data. Dosimetric factors are included in the program. The program is in FORTRAN IV language and was run on

  1. Dosing of Enoxaparin in Renal Impairment.

    Science.gov (United States)

    Shaikh, Suhail A; Regal, Randolph E

    2017-04-01

    To review enoxaparin treatment dosing, pharmacokinetics, and clinical outcomes data in patients with renal impairment and to examine the current two-tiered dosing regimen approved by the Food and Drug Administration (FDA). A literature search of PubMed (1990-2016) was performed using the search terms low-molecular-weight heparin, unfractionated heparin, bleeding, enoxaparin, renal impairment, pharmacokinetics, and hemodialysis. All studies assessing the pharmacokinetic properties of enoxaparin in patients with renal impairment were evaluated. In addition, all retrospective and prospective studies assessing the safety and efficacy of enoxaparin treatment in this population were evaluated. Five pharmacokinetic studies evaluated changes in the pharmacokinetics of enoxaparin in patients with renal impairment. In these studies, enoxaparin clearance was reduced by 17% to 44% in patients with mild and moderate renal impairment. Six retrospective studies evaluated the safety of enoxaparin in patients with renal impairment. In one study, patients with moderate renal impairment were at increased risk of bleeding when using the current FDA-approved two-tiered scheme (odds ratio, 4.7; 95% confidence interval, 1.7-13.0; P = 0.002). Another study demonstrated that individualized enoxaparin dosing, when compared to FDA-approved dosing, resulted in a decreased risk of bleeding. Two retrospective studies evaluated efficacy. One of these studies compared reduced-dose enoxaparin with unfractionated heparin; there was a trend toward lower incidences of thromboembolism and 30-day mortality with reduced-dose enoxaparin. Hospital length of stay also decreased with reduced-dosed enoxaparin. This paper highlights the differences in the pharmacokinetic properties and safety and efficacy outcomes in multiple degrees of renal impairment when using treatment-dose enoxaparin. Given the literature highlighted in this review, a more multitiered enoxaparin renal dosing strategy-perhaps shifting

  2. Radiation dose optimization in thoracic imaging.

    Science.gov (United States)

    Tack, D

    2010-01-01

    Guidelines for reduction of CT radiation dose were introduced in 1997 and are now more than 12 years old. The process initiated by the European Regulatory authorities to reduce the excess of radiation from CT has however not produced the expected results. Reference diagnostic levels (DRL) from surveys are still twice as high as needed in most European countries and were not significantly reduced as compared to the initial European ones. Many factors may at least explain partially the lack of dose reduction. One of them is the complexity of the dose optimization process while maintaining image quality at a diagnostically acceptable level. Chest is an anatomical region where radiation dose could be substantially reduced because of high natural contrasts between structures, such as air in the lungs and fat in the mediastinum. In this article, the concept of CT radiation dose optimization and the factors that contribute to maintain global excess in radiation dose are reviewed and a brief summary of results from research in the field of chest CT radiation dose is given.

  3. Low doses effects

    International Nuclear Information System (INIS)

    Tubiana, M.

    1997-01-01

    In this article is asked the question about a possible carcinogens effect of low dose irradiation. With epidemiological data, knowledge about the carcinogenesis, the professor Tubiana explains that in spite of experiments made on thousand or hundred of thousands animals it has not been possible to bring to the fore a carcinogens effect for low doses and then it is not reasonable to believe and let the population believe that low dose irradiation could lead to an increase of neoplasms and from this point of view any hardening of radiation protection standards could in fact, increase anguish about ionizing radiations. (N.C.)

  4. Properties of heavyweight concrete produced with barite

    International Nuclear Information System (INIS)

    Topcu, Ilker Bekir

    2003-01-01

    Heavyweight concrete has been used for the prevention of seepage from radioactive structures due to the harmful effect of radioactive rays to living bodies (i.e., carcinogenic, etc.). The most important point about heavyweight concrete is the determination of w/c ratio. Selected cement dosage should be both high enough to allow for radioactive impermeability and low enough to prevent splits originating from shrinkage. In this study, heavyweight concrete mixtures at different w/c ratios were prepared in order to determine the most favorable w/c ratio of heavyweight concrete produced with barite. Physical and mechanical experiments were first carried out, and then by comparison with the results of other related studies the findings of this study were obtained. At the end of the study, it was found that the most favorable w/c ratio for heavyweight concrete is 0.40 and the cement dosage should not be lower than 350 kg/m 3

  5. Computing effective dose in cardiac CT

    Science.gov (United States)

    Huda, Walter; Tipnis, Sameer; Sterzik, Alexander; Schoepf, U. Joseph

    2010-07-01

    We present a method of estimating effective doses in cardiac CT that accounts for selected techniques (kV mAs-1), anatomical location of the scan and patient size. A CT dosimetry spreadsheet (ImPACT CT Patient Dosimetry Calculator) was used to estimate effective doses (E) using ICRP 103 weighting factors for a 70 kg patient undergoing cardiac CT examinations. Using dose length product (DLP) for the same scans, we obtained values of E/DLP for three CT scanners used in cardiac imaging from two vendors. E/DLP ratios were obtained as a function of the anatomical location in the chest and for x-ray tube voltages ranging from 80 to 140 kV. We also computed the ratio of the average absorbed dose in a water cylinder modeling a patient weighing W kg to the corresponding average absorbed dose in a water cylinder equivalent to a 70 kg patient. The average E/DLP for a 16 cm cardiac heart CT scan was 26 µSv (mGy cm)-1, which is about 70% higher than the current E/DLP values used for chest CT scans (i.e. 14-17 µSv (mGy cm)-1). Our cardiac E/DLP ratios are higher because the cardiac region is ~30% more radiosensitive than the chest, and use of the ICRP 103 tissue weighting factors increases cardiac CT effective doses by ~30%. Increasing the x-ray tube voltage from 80 to 140 kV increases the E/DLP conversion factor for cardiac CT by 17%. For the same incident radiation at 120 kV, doses in 45 kg adults were ~22% higher than those in 70 kg adults, whereas doses in 120 kg adults were ~28% lower. Accurate estimates of the patient effective dose in cardiac CT should use ICRP 103 tissue weighting factors, and account for a choice of scan techniques (kV mAs-1), exposed scan region, as well as patient size.

  6. Reproducibility of isotope ratio measurements

    International Nuclear Information System (INIS)

    Elmore, D.

    1981-01-01

    The use of an accelerator as part of a mass spectrometer has improved the sensitivity for measuring low levels of long-lived radionuclides by several orders of magnitude. However, the complexity of a large tandem accelerator and beam transport system has made it difficult to match the precision of low energy mass spectrometry. Although uncertainties for accelerator measured isotope ratios as low as 1% have been obtained under favorable conditions, most errors quoted in the literature for natural samples are in the 5 to 20% range. These errors are dominated by statistics and generally the reproducibility is unknown since the samples are only measured once

  7. GOLD and the fixed ratio

    Directory of Open Access Journals (Sweden)

    Vestbo J

    2012-09-01

    Full Text Available Jørgen VestboUniversity of Manchester, Manchester, UKI read with interest the paper entitled "Diagnosis of airway obstruction in the elderly: contribution of the SARA study" by Sorino et al in a recent issue of this journal.1 Being involved in the Global Initiative for Obstructive Lung Diseases (GOLD, it is nice to see the interest sparked by the GOLD strategy document. However, in the paper by Sorino et al, there are a few misunderstandings around GOLD and the fixed ratio (forced expiratory volume in 1 second/forced volume vital capacity < 0.70 that need clarification.View original paper by Sorino and colleagues.

  8. Producing superhydrophobic roof tiles

    International Nuclear Information System (INIS)

    Carrascosa, Luis A M; Facio, Dario S; Mosquera, Maria J

    2016-01-01

    Superhydrophobic materials can find promising applications in the field of building. However, their application has been very limited because the synthesis routes involve tedious processes, preventing large-scale application. A second drawback is related to their short-term life under outdoor conditions. A simple and low-cost synthesis route for producing superhydrophobic surfaces on building materials is developed and their effectiveness and their durability on clay roof tiles are evaluated. Specifically, an organic–inorganic hybrid gel containing silica nanoparticles is produced. The nanoparticles create a densely packed coating on the roof tile surface in which air is trapped. This roughness produces a Cassie–Baxter regime, promoting superhydrophobicity. A surfactant, n-octylamine, was also added to the starting sol to catalyze the sol–gel process and to coarsen the pore structure of the gel network, preventing cracking. The application of ultrasound obviates the need to use volatile organic compounds in the synthesis, thereby making a ‘green’ product. It was also demonstrated that a co-condensation process effective between the organic and inorganic species is crucial to obtain durable and effective coatings. After an aging test, high hydrophobicity was maintained and water absorption was completely prevented for the roof tile samples under study. However, a transition from a Cassie–Baxter to a Wenzel state regime was observed as a consequence of the increase in the distance between the roughness pitches produced by the aging of the coating. (paper)

  9. Producing superhydrophobic roof tiles.

    Science.gov (United States)

    Carrascosa, Luis A M; Facio, Dario S; Mosquera, Maria J

    2016-03-04

    Superhydrophobic materials can find promising applications in the field of building. However, their application has been very limited because the synthesis routes involve tedious processes, preventing large-scale application. A second drawback is related to their short-term life under outdoor conditions. A simple and low-cost synthesis route for producing superhydrophobic surfaces on building materials is developed and their effectiveness and their durability on clay roof tiles are evaluated. Specifically, an organic-inorganic hybrid gel containing silica nanoparticles is produced. The nanoparticles create a densely packed coating on the roof tile surface in which air is trapped. This roughness produces a Cassie-Baxter regime, promoting superhydrophobicity. A surfactant, n-octylamine, was also added to the starting sol to catalyze the sol-gel process and to coarsen the pore structure of the gel network, preventing cracking. The application of ultrasound obviates the need to use volatile organic compounds in the synthesis, thereby making a 'green' product. It was also demonstrated that a co-condensation process effective between the organic and inorganic species is crucial to obtain durable and effective coatings. After an aging test, high hydrophobicity was maintained and water absorption was completely prevented for the roof tile samples under study. However, a transition from a Cassie-Baxter to a Wenzel state regime was observed as a consequence of the increase in the distance between the roughness pitches produced by the aging of the coating.

  10. TRIAL: Producing Media Catalogs.

    Science.gov (United States)

    McWeeney, Mark G.

    TRIAL (Technique for Retrieving Information from Abstracts of Literature) is an information storage and retrieval system which can be used by school media specialists to produce indexes of non-print materials. This manual provides a step by step approach for media specialists to automate their non-print holdings. These procedures can also be…

  11. Methods for producing diterpenes

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention discloses that by combining different di TPS enzymes of class I and class II different diterpenes may be produced including diterpenes not identified in nature. Surprisingly it is revealed that a di TPS enzyme of class I of one species may be combined with a di TPS enzyme...

  12. Producing Civil Society

    DEFF Research Database (Denmark)

    Feldt, Liv Egholm; Hein Jessen, Mathias

    ’ and as such dominates our way of thinking about civil society. Yet, this view hinders the understanding of how civil society is not a pre-existing or given sphere, but a sphere which is constantly produced both discursively, conceptually and practically. Through two examples; 1,the case of philanthropy in the beginning...

  13. (PHB)-producing bacteria

    African Journals Online (AJOL)

    Isolation and characterization of two novel polyhydroxybutyrate (PHB)-producing bacteria. ... subsequently studied using phenotype microarray panels which allowed the testing of the effect of more than 90 different carbon, nitrogen, sulfur and phosphorus sources as well as pH on the growth characteristics of these strains.

  14. Warfarin maintenance dose in older patients: higher average dose and wider dose frequency distribution in patients of African ancestry than those of European ancestry.

    Science.gov (United States)

    Garwood, Candice L; Clemente, Jennifer L; Ibe, George N; Kandula, Vijay A; Curtis, Kristy D; Whittaker, Peter

    2010-06-15

    Studies report that warfarin doses required to maintain therapeutic anticoagulation decrease with age; however, these studies almost exclusively enrolled patients of European ancestry. Consequently, universal application of dosing paradigms based on such evidence may be confounded because ethnicity also influences dose. Therefore, we determined if warfarin dose decreased with age in Americans of African ancestry, if older African and European ancestry patients required different doses, and if their daily dose frequency distributions differed. Our chart review examined 170 patients of African ancestry and 49 patients of European ancestry cared for in our anticoagulation clinic. We calculated the average weekly dose required for each stable, anticoagulated patient to maintain an international normalized ratio of 2.0 to 3.0, determined dose averages for groups 80 years of age and plotted dose as a function of age. The maintenance dose in patients of African ancestry decreased with age (PAfrican ancestry required higher average weekly doses than patients of European ancestry: 33% higher in the 70- to 79-year-old group (38.2+/-1.9 vs. 28.8+/-1.7 mg; P=0.006) and 52% in the >80-year-old group (33.2+/-1.7 vs. 21.8+/-3.8 mg; P=0.011). Therefore, 43% of older patients of African ancestry required daily doses >5mg and hence would have been under-dosed using current starting-dose guidelines. The dose frequency distribution was wider for older patients of African ancestry compared to those of European ancestry (PAfrican ancestry indicate that strategies for initiating warfarin therapy based on studies of patients of European ancestry could result in insufficient anticoagulation and thereby potentially increase their thromboembolism risk. Copyright 2010 Elsevier Inc. All rights reserved.

  15. Spine stereotactic body radiation therapy plans: Achieving dose coverage, conformity, and dose falloff

    International Nuclear Information System (INIS)

    Hong, Linda X.; Shankar, Viswanathan; Shen, Jin; Kuo, Hsiang-Chi; Mynampati, Dinesh; Yaparpalvi, Ravindra; Goddard, Lee; Basavatia, Amar; Fox, Jana; Garg, Madhur; Kalnicki, Shalom; Tomé, Wolfgang A.

    2015-01-01

    We report our experience of establishing planning objectives to achieve dose coverage, conformity, and dose falloff for spine stereotactic body radiation therapy (SBRT) plans. Patients with spine lesions were treated using SBRT in our institution since September 2009. Since September 2011, we established the following planning objectives for our SBRT spine plans in addition to the cord dose constraints: (1) dose coverage—prescription dose (PD) to cover at least 95% planning target volume (PTV) and 90% PD to cover at least 99% PTV; (2) conformity index (CI)—ratio of prescription isodose volume (PIV) to the PTV < 1.2; (3) dose falloff—ratio of 50% PIV to the PTV (R 50% ); (4) and maximum dose in percentage of PD at 2 cm from PTV in any direction (D 2cm ) to follow Radiation Therapy Oncology Group (RTOG) 0915. We have retrospectively reviewed 66 separate spine lesions treated between September 2009 and December 2012 (31 treated before September 2011 [group 1] and 35 treated after [group 2]). The χ 2 test was used to examine the difference in parameters between groups. The PTV V 100% PD ≥ 95% objective was met in 29.0% of group 1 vs 91.4% of group 2 (p < 0.01) plans. The PTV V 90% PD ≥ 99% objective was met in 38.7% of group 1 vs 88.6% of group 2 (p < 0.01) plans. Overall, 4 plans in group 1 had CI > 1.2 vs none in group 2 (p = 0.04). For D 2cm , 48.3% plans yielded a minor violation of the objectives and 16.1% a major violation for group 1, whereas 17.1% exhibited a minor violation and 2.9% a major violation for group 2 (p < 0.01). Spine SBRT plans can be improved on dose coverage, conformity, and dose falloff employing a combination of RTOG spine and lung SBRT protocol planning objectives

  16. Doses from radioactive methane

    International Nuclear Information System (INIS)

    Phipps, A.W.; Kendall, G.M.; Fell, T.P.; Harrison, J.D.

    1990-01-01

    A possible radiation hazard arises from exposure to methane labelled with either a 3 H or a 14 C nuclide. This radioactive methane could be released from a variety of sources, e.g. land burial sites containing radioactive waste. Standard assumptions adopted for vapours would not apply to an inert alkane like methane. This paper discusses mechanisms by which radioactive methane would irradiate tissues and provides estimates of doses. Data on skin thickness and metabolism of methane are discussed with reference to these mechanisms. It is found that doses are dominated by dose from the small fraction of methane which is inhaled and metabolised. This component of dose has been calculated under rather conservative assumptions. (author)

  17. Controllable dose; Dosis controlable

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J.T.; Anaya M, R.A. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)]. E-mail: jtar@nuclear.inin.mx

    2004-07-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  18. Acetaminophen dosing for children

    Science.gov (United States)

    ... your child, call your provider. Proper Dosing of Suppositories If your child is vomiting or will not take oral medicine, you can use suppositories. Suppositories are placed in the anus to deliver ...

  19. Dose in conventional radiography

    International Nuclear Information System (INIS)

    Acuna D, E.; Padilla R, Z. P.; Escareno J, E.; Vega C, H. R.

    2011-10-01

    It has been pointed out that medical exposures are the most significant sources of exposure to ionizing radiation for the general population. Inside the medical exposures the most important is the X-ray use for diagnosis, which is by far the largest contribution to the average dose received by the population. From all studies performed in radiology the chest radiography is the most abundant. In an X-ray machine, voltage and current are combined to obtain a good image and a reduce dose, however due to the workload in a radiology service individual dose is not monitored. In order to evaluate the dose due to chest radiography in this work a plate phantom was built according to the ISO recommendations using methylmethacrylate walls and water. The phantom was used in the Imaging department of the Zacatecas General Hospital as a radiology patient asking for a chest study; using thermoluminescent dosimeters, TLD 100 the kerma at the surface entrance was determined. (Author)

  20. Ibuprofen dosing for children

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000772.htm Ibuprofen dosing for children To use the sharing features ... much of this medicine can be harmful. How Ibuprofen can Help Your Child Ibuprofen is a type ...

  1. Determination of Absorbed Dose in Large 60-Co Fields Radiotherapy

    International Nuclear Information System (INIS)

    Hrsak, H.

    2003-01-01

    Radiation in radiotherapy has selective impact on ill and healthy tissue. During the therapy the healthy tissue receives certain amount of dose. Therefore dose calculations in outer radiotherapy must be accurate because too high doses produce damage in healthy tissue and too low doses cannot ensure efficient treatment of cancer cells. A requirement on accuracy in the dose calculations has lead to improvement of detectors, and development of absolute and relative dosimetry. Determination of the dose distribution with use of computer is based on data provided by the relative dosimetry. This paper compares the percentage depth doses in cubic water phantoms of various dimensions with percentage depth doses calculated with use of Mayneord factor from the experimental depth doses measured in water phantom of large dimension. Depth doses in water phantoms were calculated by the model of empirical dosimetrical functions. The calculations were based on the assumption that large 6 0C o photon field exceeds the phantom's limits. The experimental basis for dose calculations by the model of empirical dosimetrical functions were exposure doses measured in air and dose reduction factors because of finite phantom dimensions. Calculations were performed by fortran 90 software. It was found that the deviation of dosimetric model was small in comparison to the experimental data. (author)

  2. High aspect ratio template and method for producing same for central and peripheral nerve repair

    Science.gov (United States)

    Sakamoto, Jeff S. (Inventor); Tuszynski, Mark Henry (Inventor); Gros, Thomas (Inventor); Chan, Christina (Inventor); Mehrotra, Sumit (Inventor)

    2011-01-01

    Millimeter to nano-scale structures manufactured using a multi-component polymer fiber matrix are disclosed. The use of dissimilar polymers allows the selective dissolution of the polymers at various stages of the manufacturing process. In one application, biocompatible matrixes may be formed with long pore length and small pore size. The manufacturing process begins with a first polymer fiber arranged in a matrix formed by a second polymer fiber. End caps may be attached to provide structural support and the polymer fiber matrix selectively dissolved away leaving only the long polymer fibers. These may be exposed to another product, such as a biocompatible gel to form a biocompatible matrix. The polymer fibers may then be selectively dissolved leaving only a biocompatible gel scaffold with the pores formed by the dissolved polymer fibers. The scaffolds may be used in, among other applications, the repair of central and peripheral nerves. Scaffolds for the repair of peripheral nerves may include a reservoir for the sustained release of nerve growth factor. The scaffolds may also include a multifunctional polyelectrolyte layer for the sustained release of nerve growth factor and enhance biocompatibility.

  3. Development of Polymer Gel Systems to Improve Volumetric Sweep and Reduce Producing Water/Oil Ratios

    Energy Technology Data Exchange (ETDEWEB)

    G. Paul Willhite; Stan McCool; Don W. Green; Min Cheng; Feiyan Chen

    2005-12-31

    Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of a 42-month research program that focused on the understanding of gelation chemistry and the fundamental mechanisms that alter the flows of oil and water in reservoir rocks after a gel treatment. Work was conducted on a widely applied system in the field, the partially hydrolyzed polyacrylamide-chromium acetate gel. Gelation occurs by network formation through the crosslinking of polyacrylamide molecules as a result of reaction with chromium acetate. Pre-gel aggregates form and grow as reactions between chromium acetate and polyacrylamide proceed. A rate equation that describes the reaction between chromium acetate and polymer molecules was regressed from experimental data. A mathematical model that describes the crosslinking reaction between two polymer molecules as a function of time was derived. The model was based on probability concepts and provides molecular-weight averages and molecular-weight distributions of the pre-gel aggregates as a function of time and initial system conditions. Average molecular weights of pre-gel aggregates were measured as a function of time and were comparable to model simulations. Experimental methods to determine molecular weight distributions of pre-gel aggregates were unsuccessful. Dissolution of carbonate minerals during the injection of gelants causes the pH of the gelant to increase. Chromium precipitates from solution at the higher pH values robbing the gelant of crosslinker. Experimental data on the transport of chromium acetate solutions through dolomite cores were obtained. A mathematical model that describes the transport of brine and chromium acetate solutions through rocks containing carbonate minerals was used to simulate the experimental results and data from literature. Gel treatments usually reduce the permeability to water to a greater extent than the permeability to oil is reduced. This phenomenon is referred to as disproportionate permeability reduction (DPR). Flow experiments were conducted in sandpacks to determine the effect of polymer and chromium concentrations on DPR. All gels studied reduced the permeability to water by a greater factor than the factor by which the oil permeability was reduced. Greater DPR was observed as the concentrations of polymer and chromium were increased. A conceptual model of the mechanisms responsible for DPR is presented. Primary features of the model are (1) the development of flow channels through the gel by dehydration and displacement of the gel and by re-connection of pre-treatment, residual oil volume and (2) high flow resistance in the channels during water flow is caused by significant saturations of oil remaining in the channels. A similar study of DPR was conducted in Berea sandstone cores. Both oil and water permeabilities were reduced by much smaller factors in Berea sandstone cores than in similar treatments in sandpacks. Poor maturation of the gelant in the Berea rock was thought to be caused by fluid-rock interactions that interfered with the gelation process.

  4. DEVELOPMENT OF POLYMER GEL SYSTEMS TO IMPROVE VOLUMETRIC SWEEP AND REDUCE PRODUCING WATER/OIL RATIOS

    Energy Technology Data Exchange (ETDEWEB)

    G. Paul Willhite; Stan McCool; Don W. Green; Min Cheng; Rajeev Jain; Tuan Nguyen

    2003-11-01

    Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of the first year of a three-year research program that is aimed at the understanding of the chemistry of gelation and the fundamental mechanisms that alter the flows of oil and water in reservoir rocks after a gel treatment. Work has focused on a widely-applied system in field applications, the partially hydrolyzed polyacrylamide-chromium acetate gel. Gelation occurs by network formation through the crosslinking of polyacrylamide molecules as a result of reaction with chromium acetate. The initial reaction between chromium acetate and one polymer is referred to as the uptake reaction. The uptake reaction was studied as functions of chromium and polymer concentrations and pH values. Experimental data were regressed to determine a rate equation that describes the uptake reaction of chromium by polyacrylamide. Pre-gel aggregates form and grow as the reactions between chromium acetate and polyacrylamide proceed. A statistical model that describes the growth of pre-gel aggregates was developed using the theory of branching processes. The model gives molecular weight averages that are expressed as functions of the conversion of the reactive sites on chromium acetate or on the polymer molecule. Results of the application of the model correlate well with experimental data of viscosity and weight-average molecular weight and gives insights into the gelation process. A third study addresses the flow of water and oil in rock material after a gel treatment. Previous works have shown that gel treatments usually reduce the permeability to water to a greater extent than the permeability to oil is reduced. This phenomenon is referred to as disproportionate permeability reduction (DPR). Flow experiments were conducted to determine the effect of polymer and chromium concentrations on DPR. All gels studied reduced the permeability to water by a greater factor than the factor by which the oil permeability was reduced. Greater DPR was observed as the concentrations of polymer and chromium were increased. Increased pressure gradients during oil flow decreased the oil permeability and the water permeability that was measured afterward. Lower pressure gradients that were applied subsequently moderately affected water permeabilities but did not affect oil permeabilities. A conceptual model of the mechanisms responsible for DPR is presented. Primary features of the model are (1) the development of flow channels through the gel by dehydration of the gel and by re-connection of pre-treatment, residual oil volume and (2) high flow resistance in the channels during water flow is caused by significant saturations of oil remaining in the channels.

  5. Effects of low doses

    International Nuclear Information System (INIS)

    Le Guen, B.

    2001-01-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  6. Gonadal doses from radiotherapy

    International Nuclear Information System (INIS)

    Solomon, S.B.; Morris, N.D.

    1980-06-01

    The method of calculation of gonadal doses arising from different radiotherapeutic procedures is described. The measurement of scatter factors to the gonads from superficial and deep therapy is detailed and the analytic fits to the experimental data, as a function of field position, field size and beam energy are given. The data used to calculate the gonadal doses from treatments using linear accelerators, teletherapy and sealed sources are described and the analytic fits to the data given

  7. Detection of lung nodules with low-dose spiral CT: comparison with conventional dose CT

    International Nuclear Information System (INIS)

    Zhu Tianzhao; Tang Guangjian; Jiang Xuexiang

    2004-01-01

    Objective: To investigate the effect of reducing scan dose on the lung nodules detection rate by scanning a lung nodule model at low dose and conventional dose. Methods: The lung and the thoracic cage were simulated by using a cyst filled with water surrounded by a roll bandage. Flour, butter, and paraffin wax were mixed together by a certain ratio to simulate lung nodules of 10 mm and 5 mm in diameter with the CT values ranging from -10 to 50 HU. Conventional-dose scan (240 mA, 140 kV) and low-dose scan of three different levels (43 mA, 140 kV; 50 mA, 120 kV; 75 mA, 80 kV) together with three different pitches (1.0, 1.5, and 2.0) were performed. The images of the simulated nodules were combined with the CT images of a normal adult's upper, middle, and inferior lung. Three radiologists read the images and the number of the nodules they detected including both the real ones and the false-positive ones was calculated to investigate weather there was any difference among different doses, pitch groups, and different locations. Results: The detection rate of the 10 mm and 5 mm nodules was 100% and 89.6% respectively by the low-dose scan. There was no difference between low-dose and conventional-dose CT (χ 2 =0.6907, P>0.70). The detection rate of 5 mm nodules declined when large pitch was used. Conclusion: The detection rates of 10 mm and 5 mm nodules had no difference between low-dose CT and conventional-dose CT. As the pitch augmented, the detection rate for the nodules declined

  8. Effective dose in abdominal digital radiography: Patient factor

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-08-15

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

  9. CONDOS-II, Radiation Dose from Consumer Product Distribution Chain

    International Nuclear Information System (INIS)

    1984-01-01

    1 - Description of problem or function: This code was developed under sponsorship of the Nuclear Regulatory Commission to serve as a tool for assessing radiation doses that may be associated with consumer products that contain radionuclides. The code calculates radiation dose equivalents resulting from user-supplied scenarios of exposures to radionuclides contained in or released from sources that contain radionuclides. Dose equivalents may be calculated to total body, skin surface, skeletal bone, testes, ovaries, liver, kidneys, lungs, and maximally exposed segments of the gastrointestinal tract from exposures via (1) direct, external irradiation by photons (including Bremsstrahlung) emitted from the source, (2) external irradiation by photons during immersion in air containing photon-emitting radionuclides that have escaped from the source, (3) internal exposures by all radiations emitted by inhaled radionuclides that have escaped from the source, and (4) internal exposures by all radiations emitted by ingested radionuclides that have escaped from the source. 2 - Method of solution: Organ dose equivalents are approximated in two ways, depending on the exposure type. For external exposures, energy specific organ-to-skin-surface dose conversion ratios are used to approximate dose equivalents to specific organs from doses calculated to a point on the skin surface. The organ-to-skin ratios are incorporated in organ- and nuclide-specific dose rate factors, which are used to approximate doses during immersion in contaminated air. For internal exposures, 50 year dose equivalents are calculated using organ- and nuclide-specific, 50 year dose conversion factors. Doses from direct, external exposures are calculated using the energy-specific dose conversion ratios, user supplied exposure conditions, and photon flux approximations for eleven source geometries. Available source geometries include: point, shielded and unshielded; line, shielded and unshielded; disk, shielded

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

    Science.gov (United States)

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

    2016-05-01

    ratios ranging between 0.9 and 1.1 and variations for different organs and protocols below 20%. The triple phantom setup allowed us to take into account scatter dose contributions, but nonetheless, the correlation with the evaluated organ doses was not improved with this method. The simulation of rotational geometry and of asymmetric beam distribution by means of pcxmc 2.0 enabled us to determine patient organ doses depending on weight, height and gender. Alternatively, the measurement of an in phantom dose indicator combined with proper correction coefficients can be a useful tool for a first dose estimation of in-field organs. The data and coefficients provided in this study can be applied to any patient undergoing a scan by an Elekta XVI equipment.

  11. The effect of foaming agent doses on lightweight geopolymer concrete metakaolin based

    Science.gov (United States)

    Risdanareni, Puput; Hilmi, Aldi; Susanto, Prijono Bagus

    2017-04-01

    The aims of this study is to obtain optimal doses of foaming agent on lightweight geopolymer concrete using fly Ash (FA) and metakaolin (MK) as raw materials. Several test was conducted in order to obtained characteristics of geopolymer lightweight concrete using foaming agent with different doses. The levels of foaming agent used was 0%, 0.3%, 0.6% and 0.9% from the binder weight. Level of metakolin content of 25% by precursor mass were applied in this research. In addition, activator solution with the ratio of Na2SiO3 / NaOH of 2 and Concentration of NaOH of 10 Molar were performed in this research. Doses of foaming agent of 0%, 0.3%, 0.6% and 0.9% by weight of the binder was used. Based on test results obtained, the best mechanical and physical properties of lightweight concrete was owned by speciment with doses of foam 0%. The recommended foam dosage is 0.3% due to its fair enough mechanical and physical properties of lightweight geopolymer concrete produced.

  12. Low doses of ionizing radiation: Relationship between biological benefit and damage induction. A synopsis

    International Nuclear Information System (INIS)

    Feinendegen, L.E.

    2005-01-01

    Absorption of ionizing radiation in biological tissue stochastically interacts with constituent atoms and molecules and always generates energy deposition (track) events accompanied by bursts of reactive oxygen species (ROS). These ROS are quite similar to those ROS that arise abundantly and constantly by normal oxidative metabolism. ROS effects from either source need attention when assessing radiation-induced alterations in biological structure and function. Endogenous ROS alone induce about 10 6 DNA oxyadducts per cell per day compared to about 5x10 -3 total DNA damage per average cell per day from background radiation exposure (1 mGy per year). At this background level, the corresponding ratio of probabilities of endogenous versus radiogenic DNA double strand breaks (DSBs) per cell per day is about 103 with some 25-40 % of low-LET caused radiogenic DNA-DSBs being of the multi-damage-site type. Radiogenic DNA damage increases in proportion to absorbed dose over a certain dose range. By evolution, tissues possess physiological mechanisms of protection against an array of potentially toxic agents, externally from the environment and endogenously from metabolism, mainly against the abundantly and constantly produced ROS. Ad hoc protection operates at a level that is genetically determined. Following small to moderate perturbation of cell-tissue homeostasis by a toxic impact, adaptive responses develop with a delay and may last from hours to weeks, even months, and aim at protecting the system against renewed insults. Protective responses encompass defense by scavenging mechanisms, DNA repair, damage removal largely by apoptosis and immune responses, as well as changes in cell proliferation. Acute low-dose irradiation below about 0.2 Gy can not only disturb cell-tissue homeostasis but also initiate adaptived protection that appears with a delay of hours and may last from less than a day to months. The balance between damage production and adaptive protection favors

  13. Applicability of ambient dose equivalent H*(d) in mixed radiation fields - a critical discussion

    International Nuclear Information System (INIS)

    Hajek, M.; Vana, N.

    2004-01-01

    For purposes of routine radiation protection, it is desirable to characterize the potential irradiation of individuals in terms of a single dose equivalent quantity that would exist in a phantom approximating the human body. The phantom of choice is the ICRU sphere made of 30 cm diameter tissue-equivalent plastic with a density of 1 g.cm-3 and a mass composition of 76.2 % O, 11.1 % C, 10.1 % H and 2.6 % N. Ambient dose equivalent, H*(d), was defined in ICRU report 51 as the dose equivalent that would be produced by an expanded and aligned radiation field at a depth d in the ICRU sphere. The recommended reference depths are 10 mm for strongly penetrating radiation and 0.07 mm for weakly penetrating radiation, respectively. As an operational quantity in radiation protection, H*(d) shall serve as a conservative and directly measurable estimate of protection quantities, e.g. effective dose E, which in turn are intended to give an indication of the risk associated with radiation exposure. The situation attains increased complexity in radiation environments being composed of a variety of charged and uncharged particles in a broad energetic spectrum. Radiation fields of similarly complex nature are, for example, encountered onboard aircraft and in space. Dose equivalent was assessed as a function of depth in quasi tissue-equivalent spheres by means of thermoluminescent dosemeters evaluated according to the high-temperature ratio (HTR) method. The presented experiments were performed both onboard aircraft and the Russian space station Mir. As a result of interaction processes within the phantom body, the incident primary spectrum may be significantly modified with increasing depth. For the radiation field at aviation altitudes we found the maximum of dose equivalent in a depth of 60 mm which conflicts with the 10 mm value recommended by ICRU. Contrary, for the space radiation environment the maximum dose equivalent was found at the surface of the sphere. This suggests that

  14. Applicability of Ambient Dose Equivalent H (d) in Mixed Radiation Fields - A Critical Discussion

    International Nuclear Information System (INIS)

    Vana, R.; Hajek, M.; Bergerm, T.

    2004-01-01

    For purposes of routine radiation protection, it is desirable to characterize the potential irradiation of individuals in terms of a single dose equivalent quantity that would exist in a phantom approximating the human body. The phantom of choice is the ICRU sphere made of 30 cm diameter tissue-equivalent plastic with a density of 1 g/cm3 and a mass composition of 76.2% O, 11.1% C, 10.1% H and 2.6% N. Ambient dose equivalent, H(d), was defined in ICRU report 51 as the dose equivalent that would be produced by an expanded and aligned radiation field at a depth d in the ICRU sphere. The recommended reference depths are 10 mm for strongly penetrating radiation and 0.07 mm for weakly penetrating radiation, respectively. As an operational quantity in radiation protection, H(d) shall serve as a conservative and directly measurable estimate of protection quantities, e.g. effective dose E, which in turn are intended to give an indication of the risk associated with radiation exposure. The situation attains increased complexity in radiation environments being composed of a variety of charged and uncharged particles in a broad energetic spectrum. Radiation fields of similarly complex nature are, for example, encountered onboard aircraft and in space. Dose equivalent was assessed as a function of depth in quasi tissue-equivalent spheres by means of thermoluminescent dosemeters evaluated according to the high-temperature ratio (HTR) method. The presented experiments were performed both onboard aircraft and the Russian space station Mir. As a result of interaction processes within the phantom body, the incident primary spectrum may be significantly modified with increasing depth. For the radiation field at aviation altitudes we found the maximum of dose equivalent in a depth of 60 mm which conflicts with the 10 mm value recommended by ICRU. Contrary, for the space radiation environment the maximum dose equivalent was found at the surface of the sphere. This suggests that skin

  15. Producing colloids with microfluidics

    Science.gov (United States)

    Pannacci, Nicolas; Willaime, Herve; Tabeling, Patrick

    2008-11-01

    Submicronic emulsions are commonly used in pharmaceutical, food, cosmetic and material industries. Standard microfluidic tool is particularly convenient to produce in a very controlled way either droplets of typical diameter ranging from 10 to 300 microns with a perfect monodispersity (nanodrops in a way that is slightly dependent on the fluids used. The control on such a flow authorizes the adjustment of the diameter of the colloids formed. We will show brownian particles from 860 nm to 1.3 μm in diameter obtained in such way and their clustering into crystals thanks to their high monodispersity. These first experimental results are very promising and make evident the great potential of micro and nano-fluidics to produce nano-emulsions or colloids with very controlled size that metamaterials can require.

  16. High-resolution low-dose scanning transmission electron microscopy.

    Science.gov (United States)

    Buban, James P; Ramasse, Quentin; Gipson, Bryant; Browning, Nigel D; Stahlberg, Henning

    2010-01-01

    During the past two decades instrumentation in scanning transmission electron microscopy (STEM) has pushed toward higher intensity electron probes to increase the signal-to-noise ratio of recorded images. While this is suitable for robust specimens, biological specimens require a much reduced electron dose for high-resolution imaging. We describe here protocols for low-dose STEM image recording with a conventional field-emission gun STEM, while maintaining the high-resolution capability of the instrument. Our findings show that a combination of reduced pixel dwell time and reduced gun current can achieve radiation doses comparable to low-dose TEM.

  17. Means for producing gas

    Energy Technology Data Exchange (ETDEWEB)

    Reichhelm, G.L.

    1929-01-22

    This patent describes a gas-generating apparatus which works in combination with a gas-generating receptacle. The process requires a means for supplying finely divided carbon to said receptable, means for supplying a flame under pressure to hold said carbon in suspension, a conduit for conducting the combustible gas produced from said receptacle, and synchronously operating mechanical means for controlling said carbon-supplying means and said flame-supplying means.

  18. Thymoquinone enhances cisplatin-induced neprotoxicity in high dose

    Directory of Open Access Journals (Sweden)

    Ahmet Dirican

    2016-01-01

    Conclusions: This study showed that the administration of cisplatin and high dose of TQ act synergistically to produce nephrotoxicity and the involvement of apoptotic pathway and proximal tubule damage might be the leading cause of on this effect.

  19. Kin discrimination and sex ratios in a parasitoid wasp

    NARCIS (Netherlands)

    Reece, S.E.; Shuker, D.M.; Pen, I.R.; Duncan, A.B.; Choudhary, A.; Batchelor, C.M.; West, S.A.

    Sex ratio theory provides a clear and simple way to test if nonsocial haplodiploid wasps can discriminate between kin and nonkin. Specifically, if females can discriminate siblings from nonrelatives, then they are expected to produce a higher proportion of daughters if they mate with a sibling. This

  20. Gain ratio based fuzzy weighted association rule mining classifier for ...

    Indian Academy of Sciences (India)

    and 'chest pain=high', 'a risk level of heart disease =medium' is a fuzzy quantitative associa- tion rule ... to assign different support value at each level of abstraction to produce a large number of rules generated as a .... gain ratio based ranking is used as a user defined weight value for each potential attribute as shown in ...

  1. A modified method of calculating the lateral build-up ratio for small electron fields

    International Nuclear Information System (INIS)

    Tyner, E; McCavana, P; McClean, B

    2006-01-01

    This note outlines an improved method of calculating dose per monitor unit values for small electron fields using Khan's lateral build-up ratio (LBR). This modified method obtains the LBR directly from the ratio of measured, surface normalized, electron beam percentage depth dose curves. The LBR calculated using this modified method more accurately accounts for the change in lateral scatter with decreasing field size. The LBR is used along with Khan's dose per monitor unit formula to calculate dose per monitor unit values for a set of small fields. These calculated dose per monitor unit values are compared to measured values to within 3.5% for all circular fields and electron energies examined. The modified method was further tested using a small triangular field. A maximum difference of 4.8% was found. (note)

  2. Methods and systems for producing syngas

    Science.gov (United States)

    Hawkes, Grant L; O& #x27; Brien, James E; Stoots, Carl M; Herring, J. Stephen; McKellar, Michael G; Wood, Richard A; Carrington, Robert A; Boardman, Richard D

    2013-02-05

    Methods and systems are provided for producing syngas utilizing heat from thermochemical conversion of a carbonaceous fuel to support decomposition of at least one of water and carbon dioxide using one or more solid-oxide electrolysis cells. Simultaneous decomposition of carbon dioxide and water or steam by one or more solid-oxide electrolysis cells may be employed to produce hydrogen and carbon monoxide. A portion of oxygen produced from at least one of water and carbon dioxide using one or more solid-oxide electrolysis cells is fed at a controlled flow rate in a gasifier or combustor to oxidize the carbonaceous fuel to control the carbon dioxide to carbon monoxide ratio produced.

  3. House sparrow biomarkers as lead pollution bioindicators. Evaluation of dose and exposition length on hematological and oxidative stress parameters.

    Science.gov (United States)

    Cid, Fabricio D; Fernández, Noelia C; Pérez-Chaca, María V; Pardo, Rafael; Caviedes-Vidal, Enrique; Chediack, Juan G

    2018-06-15

    House sparrows (Passer domesticus) have been proposed as a key ecological indicator of urban pollution. Remarkably, we lack knowledge about the physiological effects of lead on this bird species. Therefore, this study was aimed to evaluate the effect of Pb on several physiological parameters in house sparrows exposed to environmental Pb concentrations. In a first experiment, birds were exposed to Pb sub-lethal doses (from 1.3 to 14.0 µg of Pb/g animal/day) during 5 days, which resulted in a dose response increase of blood Pb levels and decrease of blood ALAD activity. However, at the higher doses tested (> 7 μg of Pb/g animal/day) the blood ALAD activity inhibition (~82%) remained constant. Hematocrit and hemoglobin were significantly reduced only at the highest-doses, and the stress indicator, heterophils to lymphocyte (H/L) ratio, did not show apparent changes. In a second experiment, house sparrows were exposed to Pb in drinking water (12.3 ppm) during either 15 or 30 days. Pb concentration used in this study was enough to produce blood lead levels equivalents to those found recently in house sparrows inhabiting urban areas, reduced blood ALAD activity and inversion of the H/L ratio. Decreasing blood ALAD activities were correlated with increasing blood Pb levels. In addition, Pb exposure produced modification in the levels of hepatic antioxidant enzymes, increased GST activity and decreased CAT activity, without lipid peroxidation. In conclusion, our results suggest that blood ALAD activity is a reliable and sensitive biomarker for environmental Pb exposure in house sparrows, additionally chronic exposure produce physiological stress (H/L inversion) and small changes in antioxidant enzyme activity. Finally, this specie could be considered a bioindicator for monitoring the urban Pb contamination. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Dosimetry in high dose rate endoluminal brachytherapy

    International Nuclear Information System (INIS)

    Uno, Takashi; Kotaka, Kikuo; Itami, Jun

    1994-01-01

    In endoluminal brachytherapy for the tracheobronchial tree, esophagus, and bile duct, a reference point for dose calculation has been often settled at 1 cm outside from the middle of source travel path. In the current study, a change in the ratio of the reference point dose on the convex to concave side (Dq/Dp) was calculated, provided the source travel path bends as is the case in most endoluminal brachytherapies. Point source was presumed to move stepwise at 1 cm interval from 4 to 13 locations. Retention time at each location was calculated by personal computer so as to deliver equal dose at 1 cm from the linear travel path. With the retention time remaining constant, the change of Dq/Dp was assessed by bending the source travel path. Results indicated that the length of the source travel path and radius of its curve influenced the pattern of change in Dq/Dp. Therefore, it was concluded that the difference in reference dose on the convex and concave side of the curved path is not negligible under certain conditions in endoluminal brachytherapy. In order to maintain the ratio more than 0.9, relatively greater radius was required when the source travel path was decreased. (author)

  5. Therapeutic effects of low radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Trott, K.R. (Dept. of Radiation Biology, St. Bartholomew' s Medical College, London (United Kingdom))

    1994-01-01

    This editorial explores the scientific basis of radiotherapy with doses of < 1 Gy for various non-malignant conditions, in particular dose-effect relationships, risk-benefit considerations and biological mechanisms. A review of the literature, particularly clinical and experimental reports published more than 50 years ago was conducted to clarify the following problems. 1. The dose-response relationships for the therapeutic effects on three groups of conditions: non-malignant skin disease, arthrosis and other painful degenerative joint disorders and anti-inflammatory radiotherapy; 2. risks after radiotherapy and after the best alternative treatments; 3. the biological mechanisms of the different therapeutic effects. Radiotherapy is very effective in all three groups of disease. Few dose-finding studies have been performed, all demonstrating that the optimal doses are considerable lower than the generally recommended doses. In different conditions, risk-benefit analysis of radiotherapy versus the best alternative treatment yields very different results: whereas radiotherapy for acute postpartum mastitis may not be justified any more, the risk-benefit ratio of radiotherapy of other conditions and particularly so in dermatology and some anti-inflammatory radiotherapy appears to be more favourable than the risk-benefit ratio of the best alternative treatments. Radiotherapy can be very effective treatment for various non-malignant conditions such as eczema, psoriasis, periarthritis humeroscapularis, epicondylitis, knee arthrosis, hydradenitis, parotitis and panaritium and probably be associated with less acute and long-term side effects than similarly effective other treatments. Randomized clinical studies are required to find the optimal dosage which, at present, may be unnecessarily high.

  6. The effects of brief-stimulus presentations in fixed-ratio second-order schedules

    OpenAIRE

    Cohen, Steven L.; Calisto, George

    1981-01-01

    Pigeons' responses were reinforced according to a three-component multiple schedule. In Component 1, key pecks produced food according to a fixed-ratio second-order schedule with fixed-ratio units. Here, a fixed number of fixed-ratio units produced food, and the brief stimulus terminating each unit also accompanied food. Responses in Component 2 produced food on an identical schedule except that the brief stimulus was not paired with food. Component 3 contained a simple fixed-ratio schedule w...

  7. Bremsstrahlung doses from natural uranium ingots

    International Nuclear Information System (INIS)

    Anderson, J. L.; Hertel, N. E.

    2005-01-01

    In the past, some privately owned commercial facilities in the United States were involved in producing or processing radioactive materials used in the production of atomic weapons. Seven different geometrical objects, representative of the configurations of natural uranium metal potentially encountered by workers at these facilities, are modelled to determine gamma ray and Bremsstrahlung dose rates. The dose rates are calculated using the MCNP5 code and also by using the MICROSHIELD point-kernel code. Both gamma ray and Bremsstrahlung dose rates are calculated and combined to obtain a total dose rate. The two methods were found to be in good agreement despite differences in modelling assumptions and method differences. Computed total dose rates on the surface of these objects ranged from ∼51-84 μSv h -1 and 17-95 μSv h -1 using the MCNP5 and the MICROSHIELD modeling, respectively. The partitioning of the computed dose rates between gamma rays and Bremsstrahlung were the same order of magnitude for each object. (authors)

  8. Bremsstrahlung doses from natural uranium ingots.

    Science.gov (United States)

    Anderson, Jeri L; Hertel, Nolan E

    2005-01-01

    In the past, some privately owned commercial facilities in the United States were involved in producing or processing radioactive materials used in the production of atomic weapons. Seven different geometrical objects, representative of the configurations of natural uranium metal potentially encountered by workers at these facilities, are modelled to determine gamma ray and bremsstrahlung dose rates. The dose rates are calculated using the MCNP5 code and also by using the MICROSHIELD point-kernel code. Both gamma ray and bremsstrahlung dose rates are calculated and combined to obtain a total dose rate. The two methods were found to be in good agreement despite differences in modelling assumptions and method differences. Computed total dose rates on the surface of these objects ranged from approximately 51-84 microSv h(-1) and 17-95 microSv h(-1) using the MCNP5 and the MICROSHIELD modeling, respectively. The partitioning of the computed dose rates between gamma rays and bremsstrahlung were the same order of magnitude for each object.

  9. Ingestion of Nevada Test Site Fallout: Internal dose estimates

    International Nuclear Information System (INIS)

    Whicker, F.W.; Kirchner, T.B.; Anspaugh, L.R.

    1996-01-01

    This paper summarizes individual and collective dose estimates for the internal organs of hypothetical yet representative residents of selected communities that received measurable fallout from nuclear detonations at the Nevada Test Site. The doses, which resulted from ingestion of local and regional food products contaminated with over 20 radionuclides, were estimated with use of the PATHWAY food-chain-transport model to provide estimates of central tendency and uncertainty. The thyroid gland received much higher doses than other internal organs and tissues. In a avery few cases, infants might have received thyroid doses in excess of 1 Gy, depending on location, diet, and timing of fallout. 131 I was the primary thyroid dose contributor, and fresh milk was the main exposure pathway. With the exception of the thyroid, organ doses from the ingestion pathway were much smaller (<3%) than those from external gamma exposure to deposited fallout. Doses to residents living closest to the Nevada Test Site were contributed mainly by a few fallout events; doses to more distantly located people were generally smaller, but a greater number of events provided measurable contributions. The effectiveness of different fallout events in producing internal organ doses through ingestion varied dramatically with seasonal timing of the test, with maximum dose per unit fallout occurring for early summer depositions when milk cows were on pasture and fresh, local vegetables were used. Within specific communities, internal doses differed by age, sex, and lifestyle. Collective internal dose estimates for specific geographic areas are provided

  10. Capture and analysis of radiation dose reports for radiology.

    Science.gov (United States)

    Midgley, S M

    2014-12-01

    Radiographic imaging systems can produce records of exposure and dose parameters for each patient. A variety of file formats are in use including plain text, bit map images showing pictures of written text and radiation dose structured reports as text or extended markup language files. Whilst some of this information is available with image data on the hospital picture archive and communication system, access is restricted to individual patient records, thereby making it difficult to locate multiple records for the same scan protocol. This study considers the exposure records and dose reports from four modalities. Exposure records for mammography and general radiography are utilized for repeat analysis. Dose reports for fluoroscopy and computed tomography (CT) are utilized to study the distribution of patient doses for each protocol. Results for dosimetric quantities measured by General Radiography, Fluoroscopy and CT equipment are summarised and presented in the Appendix. Projection imaging uses the dose (in air) area product and derived quantities including the dose to the reference point as a measure of the air kerma reaching the skin, ignoring movement of the beam for fluoroscopy. CT uses the dose indices CTDIvol and dose length product as a measure of the dose per axial slice, and to the scanned volume. Suitable conversion factors are identified and used to estimate the effective dose to an average size patient (for CT and fluoroscopy) and the entrance skin dose for fluoroscopy.

  11. Dose evaluation of organs at risk (OAR) cervical cancer using dose volume histogram (DVH) on brachytherapy

    Science.gov (United States)

    Arif Wibowo, R.; Haris, Bambang; Inganatul Islamiyah, dan

    2017-05-01

    Brachytherapy is one way to cure cervical cancer. It works by placing a radioactive source near the tumor. However, there are some healthy tissues or organs at risk (OAR) such as bladder and rectum which received radiation also. This study aims to evaluate the radiation dose of the bladder and rectum. There were 12 total radiation dose data of the bladder and rectum obtained from patients’ brachytherapy. The dose of cervix for all patients was 6 Gy. Two-dimensional calculation of the radiation dose was based on the International Commission on Radiation Units and Measurements (ICRU) points or called DICRU while the 3-dimensional calculation derived from Dose Volume Histogram (DVH) on a volume of 2 cc (D2cc). The radiation dose of bladder and rectum from both methods were analysed using independent t test. The mean DICRU of bladder was 4.33730 Gy and its D2cc was4.78090 Gy. DICRU and D2cc bladder did not differ significantly (p = 0.144). The mean DICRU of rectum was 3.57980 Gy and 4.58670 Gy for D2cc. The mean DICRU of rectum differed significantly from D2cc of rectum (p = 0.000). The three-dimensional method radiation dose of the bladder and rectum was higher than the two-dimensional method with ratios 1.10227 for bladder and 1.28127 for rectum. The radiation dose of the bladder and rectum was still below the tolerance dose. Two-dimensional calculation of the bladder and rectum dose was lower than three-dimension which was more accurate due to its calculation at the whole volume of the organs.

  12. π0 decay branching ratios of 5ΛHe and 12ΛC hypernuclei

    International Nuclear Information System (INIS)

    Okada, S.; Ajimura, S.; Aoki, K.; Banu, A.; Bhang, H.C.; Fukuda, T.; Hashimoto, O.; Hwang, J.I.; Kameoka, S.; Kang, B.H.; Kim, E.H.; Kim, J.H.; Kim, M.J.; Maruta, T.; Miura, Y.; Miyake, Y.; Nagae, T.; Nakamura, M.; Nakamura, S.N.; Noumi, H.; Okayasu, Y.; Outa, H.; Park, H.; Saha, P.K.; Sato, Y.; Sekimoto, M.; Takahashi, T.; Tamura, H.; Tanida, K.; Toyoda, A.; Tsukada, K.; Watanabe, T.; Yim, H.J.

    2005-01-01

    We precisely measured π0 branching ratios of 5 Λ He and 12 Λ C hypernuclei produced via the (π+,K+) reaction. Using these π0 branching ratios with the π- branching ratios and lifetimes, we obtained the π0 decay widths and the non-mesonic weak decay widths with an accuracy of ∼5% (stat) for both hypernuclei

  13. Ionising energy treatment for fresh horticultural produce -mandarins and other produce, Trials 1 and 2, May-July 1987

    International Nuclear Information System (INIS)

    McLauchlan, R.L.; Brown, B.I.; Mitchell, G.E.; Aston, J.W.; Wood, A.F.; Isaacs, A.R.; Williams, S.M.; Nottingham, S.M.; Wilson, P.R.; Juffs, H.S.; Johnson, G.I.; Heather, N.W.; Giles, J.E.; Wills, P.A.

    1988-01-01

    Two trials are described on the effect of ionising energy treatment, or irradiation, on the quality, shelf-life and composition of fresh produce, mainly at doses consistent with disinfestation treatment for quarantine purposes. Trial 1, carried out in May 1987, deals with replicated treatments of Imperial mandarins and preliminary observation treatments on a range of other produce. Trial 2 deals with replicated treatments of Ellendale mandarins and preliminary observation treatments on other produce

  14. Producing images by ionography

    International Nuclear Information System (INIS)

    Pullan, B.R.; Dovas, T.; Mootes, B.M.

    1983-01-01

    A method and system for producing images by ionography and recording and storing same for display, comprising means for forming and recording a latent ionographic image on an electrically insulating film within a gas ionisation chamber between electrodes, scanning the latent image formed by an X-ray source, by means of an array of scanning electrodes movable on a platform to scan the latent image, the output signals from said scanning electrodes being amplified and digitised and thereafter placed in a digital storage and display device. (author)

  15. Assessment of internal doses

    CERN Document Server

    Rahola, T; Falk, R; Isaksson, M; Skuterud, L

    2002-01-01

    There is a definite need for training in dose calculation. Our first course was successful and was followed by a second, both courses were fully booked. An example of new tools for software products for bioassay analysis and internal dose assessment is the Integrated Modules for Bioassay Analysis (IMBA) were demonstrated at the second course. This suite of quality assured code modules have been adopted in the UK as the standard for regulatory assessment purposes. The intercomparison measurements are an important part of the Quality Assurance work. In what is known as the sup O utside workers ' directive it is stated that the internal dose measurements shall be included in the European Unions supervision system for radiation protection. The emergency preparedness regarding internal contamination was much improved by the training with and calibration of handheld instruments from participants' laboratories. More improvement will be gained with the handbook giving practical instructions on what to do in case of e...

  16. Dose Reduction Techniques

    International Nuclear Information System (INIS)

    WAGGONER, L.O.

    2000-01-01

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program

  17. Dose Reduction Techniques

    Energy Technology Data Exchange (ETDEWEB)

    WAGGONER, L.O.

    2000-05-16

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program.

  18. Dose properties of a laser accelerated electron beam and prospects for clinical application

    International Nuclear Information System (INIS)

    Kainz, K.K.; Hogstrom, K.R.; Antolak, J.A.; Almond, P.R.; Bloch, C.D.; Chiu, C.; Fomytskyi, M.; Raischel, F.; Downer, M.; Tajima, T.

    2004-01-01

    Laser wakefield acceleration (LWFA) technology has evolved to where it should be evaluated for its potential as a future competitor to existing technology that produces electron and x-ray beams. The purpose of the present work is to investigate the dosimetric properties of an electron beam that should be achievable using existing LWFA technology, and to document the necessary improvements to make radiotherapy application for LWFA viable. This paper first qualitatively reviews the fundamental principles of LWFA and describes a potential design for a 30 cm accelerator chamber containing a gas target. Electron beam energy spectra, upon which our dose calculations are based, were obtained from a uniform energy distribution and from two-dimensional particle-in-cell (2D PIC) simulations. The 2D PIC simulation parameters are consistent with those reported by a previous LWFA experiment. According to the 2D PIC simulations, only approximately 0.3% of the LWFA electrons are emitted with an energy greater than 1 MeV. We studied only the high-energy electrons to determine their potential for clinical electron beams of central energy from 9 to 21 MeV. Each electron beam was broadened and flattened by designing a dual scattering foil system to produce a uniform beam (103%>off-axis ratio>95%) over a 25x25 cm2 field. An energy window (ΔE) ranging from 0.5 to 6.5 MeV was selected to study central-axis depth dose, beam flatness, and dose rate. Dose was calculated in water at a 100 cm source-to-surface distance using the EGS/BEAM Monte Carlo algorithm. Calculations showed that the beam flatness was fairly insensitive to ΔE. However, since the falloff of the depth-dose curve (R 10 -R 90 ) and the dose rate both increase with ΔE, a tradeoff between minimizing (R 10 -R 90 ) and maximizing dose rate is implied. If ΔE is constrained so that R 10 -R 90 is within 0.5 cm of its value for a monoenergetic beam, the maximum practical dose rate based on 2D PIC is approximately 0.1 Gy min-1

  19. Radioactive cloud dose calculations

    International Nuclear Information System (INIS)

    Healy, J.W.

    1984-01-01

    Radiological dosage principles, as well as methods for calculating external and internal dose rates, following dispersion and deposition of radioactive materials in the atmosphere are described. Emphasis has been placed on analytical solutions that are appropriate for hand calculations. In addition, the methods for calculating dose rates from ingestion are discussed. A brief description of several computer programs are included for information on radionuclides. There has been no attempt to be comprehensive, and only a sampling of programs has been selected to illustrate the variety available

  20. Dose model for inhalation

    International Nuclear Information System (INIS)

    Raicevic, J.; Ninkovic, M.; Merkle, M.

    1997-01-01

    This paper deals with calculation of doses in the environment. There are in general five exposure pathways which are customarily considered within such calculations: cloud shine, ground shine, inhalation after resuspension and ingestion. Since in fact each of these exposure pathways is represented by an independent mechanism, it is usual to consider these environmental dose models separately for each exposure pathway. As one example, the inhalation of the material from the radioactive passing cloud, as well as the inhalation of the radioactive material resuspended in the air are considered, giving the same formulas which are used in the new european accident consequence assessment code system COSYMA. (author)

  1. Proximity effects in chromosome aberration induction: Dependence on radiation quality, cell type and dose.

    Science.gov (United States)

    Tello Cajiao, John James; Carante, Mario Pietro; Bernal Rodriguez, Mario Antonio; Ballarini, Francesca

    2018-04-01

    It is widely accepted that, in chromosome-aberration induction, the (mis-)rejoining probability of two chromosome fragments depends on their initial distance, r. However, several aspects of these "proximity effects" need to be clarified, also considering that they can vary with radiation quality, cell type and dose. A previous work performed by the BIANCA (BIophysical ANalysis of Cell death and chromosome Aberrations) biophysical model has suggested that, in human lymphocytes and fibroblasts exposed to low-LET radiation, an exponential function of the form exp(-r/r 0 ), which is consistent with free-end (confined) diffusion, describes proximity effects better than a Gaussian function. Herein, the investigation was extended to intermediate- and high-LET. Since the r 0 values (0.8 μm for lymphocytes and 0.7 μm for fibroblasts) were taken from the low-LET study, the results were obtained by adjusting only one model parameter, i.e. the yield of "Cluster Lesions" (CLs), where a CL was defined as a critical DNA damage producing two independent chromosome fragments. In lymphocytes, the exponential model allowed reproducing both dose-response curves for different aberrations (dicentrics, centric rings and excess acentrics), and values of F-ratio (dicentrics to centric rings) and G-ratio (interstitial deletions to centric rings). In fibroblasts, a good correspondence was found with the dose-response curves, whereas the G-ratio (and, to a lesser extent, the F-ratio) was underestimated. With increasing LET, F decreased and G increased in both cell types, supporting their role as "fingerprints" of high-LET exposure. A dose-dependence was also found at high LET, where F increased with dose and G decreased, possibly due to inter-track effects. We therefore conclude that, independent of radiation quality, in lymphocytes an exponential function can describe proximity effects at both inter- and intra-chromosomal level; on the contrary, in fibroblasts further studies

  2. Producing x-rays

    International Nuclear Information System (INIS)

    Mallozzi, P.J.; Epstein, H.M.; Jung, R.G.; Applebaum, D.C.; Fairand, B.P.; Gallagher, W.J.

    1977-01-01

    A method of producing x-rays by directing radiant energy from a laser onto a target is described. Conversion efficiency of at least about 3 percent is obtained by providing the radiant energy in a low-power precursor pulse of approximately uniform effective intensity focused onto the surface of the target for about 1 to 30 nanoseconds so as to generate an expanding unconfined coronal plasma having less than normal solid density throughout and comprising a low-density (underdense) region wherein the plasma frequency is less than the laser radiation frequency and a higher-density (overdense) region wherein the plasma frequency is greater than the laser radiation frequency and, about 1 to 30 nanoseconds after the precursor pulse strikes the target, a higher-power main pulse focused onto the plasma for about 10 -3 to 30 nanoseconds and having such power density and total energy that the radiant energy is absorbed in the underdense region and conducted into the overdense region to heat it and thus to produce x-rays therefrom with the plasma remaining substantially below normal solid density and thus facilitating the substantial emission of x-rays in the form of spectral lines arising from nonequilibrium ionization states

  3. Managing patient dose in digital radiology

    International Nuclear Information System (INIS)

    2014-01-01

    Digital techniques have the potential to improve the practice of radiology but they also risk the overuse of radiation. The main advantages of digital imaging, i.e. wide dynamic range, post processing, multiple viewing options, and electronic transfer and archiving possibilities, are clear but overexposures can occur without an adverse impact on image quality. In conventional radiography, excessive exposure produces a black film. In digital systems, good images are obtained for a large range of doses. It is very easy to obtain (and delete) images with digital fluoroscopy systems, and there may be a tendency to obtain more images than necessary. In digital radiology, higher patient dose usually means improved image quality, so a tendency to use higher patient doses than necessary could occur. Different medical imaging tasks require different levels of image quality, and doses that have no additional benefit for the clinical purpose should be avoided. Image quality can be compromised by inappropriate levels of data compression and/or post processing techniques. All these new challenges should be part of the optimisation process and should be included in clinical and technical protocols. Local diagnostic reference levels should be re-evaluated for digital imaging, and patient dose parameters should be displayed at the operator console. Frequent patient dose audits should occur when digital techniques are introduced. Training in the management of image quality and patient dose in digital radiology is necessary. Digital radiology will involve new regulations and invoke new challenges for practitioners. As digital images are easier to obtain and transmit, the justification criteria should be reinforced. Commissioning of digital systems should involve clinical specialists, medical physicists, and radiographers to ensure that imaging capability and radiation dose management are integrated. Quality control requires new procedures and protocols (visualisation, transmission

  4. SU-F-J-133: Adaptive Radiation Therapy with a Four-Dimensional Dose Calculation Algorithm That Optimizes Dose Distribution Considering Breathing Motion

    Energy Technology Data Exchange (ETDEWEB)

    Ali, I; Algan, O; Ahmad, S [University of Oklahoma Health Sciences, Oklahoma City, OK (United States); Alsbou, N [University of Central Oklahoma, Edmond, OK (United States)

    2016-06-15

    Purpose: To model patient motion and produce four-dimensional (4D) optimized dose distributions that consider motion-artifacts in the dose calculation during the treatment planning process. Methods: An algorithm for dose calculation is developed where patient motion is considered in dose calculation at the stage of the treatment planning. First, optimal dose distributions are calculated for the stationary target volume where the dose distributions are optimized considering intensity-modulated radiation therapy (IMRT). Second, a convolution-kernel is produced from the best-fitting curve which matches the motion trajectory of the patient. Third, the motion kernel is deconvolved with the initial dose distribution optimized for the stationary target to produce a dose distribution that is optimized in four-dimensions. This algorithm is tested with measured doses using a mobile phantom that moves with controlled motion patterns. Results: A motion-optimized dose distribution is obtained from the initial dose distribution of the stationary target by deconvolution with the motion-kernel of the mobile target. This motion-optimized dose distribution is equivalent to that optimized for the stationary target using IMRT. The motion-optimized and measured dose distributions are tested with the gamma index with a passing rate of >95% considering 3% dose-difference and 3mm distance-to-agreement. If the dose delivery per beam takes place over several respiratory cycles, then the spread-out of the dose distributions is only dependent on the motion amplitude and not affected by motion frequency and phase. This algorithm is limited to motion amplitudes that are smaller than the length of the target along the direction of motion. Conclusion: An algorithm is developed to optimize dose in 4D. Besides IMRT that provides optimal dose coverage for a stationary target, it extends dose optimization to 4D considering target motion. This algorithm provides alternative to motion management

  5. Isokinetic Hamstrings: Quadriceps Ratios in Intercollegiate Athletes.

    Science.gov (United States)

    Rosene, John M.; Fogarty, Tracey D.; Mahaffey, Brian L.

    2001-01-01

    Compared the differences in the concentric hamstrings to quadriceps (H:Q) ratio among athletes in different sports at three velocities. Measurement of H:Q ratio of both knees among male and female college athletes indicated that the H:Q ratio increased as velocity increased. No differences existed for the H:Q ratio for sport or side of body. (SM)

  6. Exposure doses to angiographers during interventional angiography

    International Nuclear Information System (INIS)

    Fukutomi, Yukimi; Yasuhara, Yoshifumi; Sugata, Shigenori; Fujii, Takashi; Kawakami, Toshiaki; Ikezoe, Junpei

    1997-01-01

    We report the exposure doses to angiographers during interventional angiography and the protective efficacy of protective aprons against X-rays in this study. The first (main) angiographer was exposed to the maximum dose of 1 μSv/min at the left chest area and lower abdominal area inside the protective apron. The second (assistant) angiographer was exposed to the maximum dose of 2 μSv/min at the left chest area and 1 μSv/min at the lower abdominal area. X-ray transmission ratio of the protective apron was 4.9 percent or less for UL25L, O percent for 0.35 mmPb and 4.3 percent or less for 0.5 mmPb. These results were lower than the dose equivalent limit based on the laws and ordinances. The protection capacities of these protective aprons proved to be sufficient. The exposure dose at the left extremity area outside the protective apron, however, was 24 times higher than at the left chest area inside. The data showed that it was not protected from scattered X-rays outside the protective apron. It is imperative to consider secondary protective material for the area outside the protective apron. Considering the risk of radiation, we need to better control exposure to angiographers. (author)

  7. Cultivating Insect Cells To Produce Recombinant Proteins

    Science.gov (United States)

    Spaulding, Glenn; Goodwin, Thomas; Prewett, Tacey; Andrews, Angela; Francis, Karen; O'Connor, Kim

    1996-01-01

    Method of producing recombinant proteins involves growth of insect cells in nutrient solution in cylindrical bioreactor rotating about cylindrical axis, oriented horizontally and infecting cells with viruses into which genes of selected type cloned. Genes in question those encoding production of desired proteins. Horizontal rotating bioreactor preferred for use in method, denoted by acronym "HARV", described in "High-Aspect-Ratio Rotating Cell-Culture Vessel" (MSC-21662).

  8. Proton beam writing for producing holographic images

    International Nuclear Information System (INIS)

    Ow, Y.S.; Breese, M.B.H.; Bettiol, A.A.

    2009-01-01

    This work reports on the writing of computer generated hologram diffraction patterns using focused 2 MeV proton beam irradiation. These patterns were designed using a ray tracing algorithm and written directly into a thick polymethylmethacrylate layer. When the developed holographic pattern was illuminated with a 650 nm laser it produced a good reconstructed image. This work provides means of forming high-resolution, high aspect ratio holographic images in polymers for applications in data storage using switchable holography.

  9. Dose Reduction Techniques

    CERN Document Server

    Waggoner, L O

    2000-01-01

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the sm...

  10. Alpha-particle doses to human organs and tissues from internally-deposited 226Ra and 228Ra

    International Nuclear Information System (INIS)

    Keane, A.T.; Schlenker, R.A.

    1981-01-01

    Estimation of radiation doses to the soft tissues from internally-deposited 226 Ra and 228 Ra is relevant to an investigation of soft-tissue malignancies in radium-exposed persons being conducted at the Center for Human Radiobiology. Alpha-particle doses in a 50-year period following a single injection of 226 Ra or 228 Ra are presented for 31 soft tissues and organs of the adult human. The dose estimates were derived from the ICRP alkaline earth model fitted to data on retention of 226 Ra in soft tissues and bone, combined with reported ratios of 226 Ra to Ca in soft tissue and bone at natural levels and the distribution of Ca in the tissues of Reference Man (ICRP23). The median of the 31 organ and tissue doses from the α-particles of 226 Ra itself is 0.08 rad per injected μCi. An additional average dose of 0.01 rad per μCi 226 Ra daughter products produced in soft tissue or transferred from bone to soft tissue. Soft-tissue doses from α-particles of the 228 Ra decay series are about six times those from 226 Ra α-particles for equal injected activities of 228 Ra and 226 Ra, with the assumption that 228 Ra daughter products do not transfer from the organ in which they are produced. The 50-year dose to the red marrow of bone from α-particles originating in bone is 0.55 rad per μCi 226 Ra injected and 1.0 rad per μCi 228 Ra injected. For ingestion by dial painters of luminous compound containg 226 Ra or 228 Ra with a daughter-to-parent activity ratio of 0.5, the dose to the mucosal alyer of the lower large intestine from α-particles originating in the gut contents is about 0.1 rad per μCi systemic intake of 226 Ra or 228 Ra

  11. SU-F-19A-10: Recalculation and Reporting Clinical HDR 192-Ir Head and Neck Dose Distributions Using Model Based Dose Calculation

    International Nuclear Information System (INIS)

    Carlsson Tedgren, A; Persson, M; Nilsson, J

    2014-01-01

    Purpose: To retrospectively re-calculate dose distributions for selected head and neck cancer patients, earlier treated with HDR 192Ir brachytherapy, using Monte Carlo (MC) simulations and compare results to distributions from the planning system derived using TG43 formalism. To study differences between dose to medium (as obtained with the MC code) and dose to water in medium as obtained through (1) ratios of stopping powers and (2) ratios of mass energy absorption coefficients between water and medium. Methods: The MC code Algebra was used to calculate dose distributions according to earlier actual treatment plans using anonymized plan data and CT images in DICOM format. Ratios of stopping power and mass energy absorption coefficients for water with various media obtained from 192-Ir spectra were used in toggling between dose to water and dose to media. Results: Differences between initial planned TG43 dose distributions and the doses to media calculated by MC are insignificant in the target volume. Differences are moderate (within 4–5 % at distances of 3–4 cm) but increase with distance and are most notable in bone and at the patient surface. Differences between dose to water and dose to medium are within 1-2% when using mass energy absorption coefficients to toggle between the two quantities but increase to above 10% for bone using stopping power ratios. Conclusion: MC predicts target doses for head and neck cancer patients in close agreement with TG43. MC yields improved dose estimations outside the target where a larger fraction of dose is from scattered photons. It is important with awareness and a clear reporting of absorbed dose values in using model based algorithms. Differences in bone media can exceed 10% depending on how dose to water in medium is defined

  12. Bioavailability of diclofenac potassium at low doses

    Science.gov (United States)

    Hinz, Burkhard; Chevts, Julia; Renner, Bertold; Wuttke, Henrike; Rau, Thomas; Schmidt, Andreas; Szelenyi, Istvan; Brune, Kay; Werner, Ulrike

    2005-01-01

    Aim Diclofenac-K has been recently launched at low oral doses in different countries for over-the-counter use. However, given the considerable first-pass metabolism of diclofenac, the degree of absorption of diclofenac-K at low doses remained to be determined. The aim of this study was to determine the bioavailability of low-dose diclofenac-K. Methods A randomized, three-way, cross-over study was performed in 10 subjects. Each received diclofenac-K, 22.5 mg via short-term i.v. infusion and orally at single doses of 12.5 mg and 25 mg. Results Mean (± SD) times to maximal plasma concentration (tmax) of diclofenac were 0.48 ± 0.28 h (12.5 mg) and 0.93 ± 0.96 h (25 mg). The absolute bioavailability of diclofenac-K after oral administration did not differ significantly in the 12.5-mg and 25-mg dose group (63.1 ± 12.6% vs. 65.1 ± 19.4%, respectively). The 90% confidence intervals for the AUC∞ and AUCt ratios for the two oral regimes were 82.6, 103.4% (point estimate 92.4%) and 86.2, 112.9% (point estimate 98.6%), respectively. These values were within the acceptance criteria for bioequivalence (80–125%). Conclusions Our data indicate that diclofenac-K is rapidly and well absorbed at low dose, and are consistent with a rapid onset of action of the drug. Abbreviations AUC, area under plasma concentraton-time curve; Cmax, peak plasma concentration; CI, confidence interval; COX, cyclooxygenase; D, dose; F, absolute bioavailability; tmax, time to reach Cmax. PMID:15606444

  13. Colorectal adenomas produce lysozyme.

    Science.gov (United States)

    Rubio, C A

    2003-01-01

    Lysozyme is an innate non-immunologic antibacterial enzyme produced by the Paneth cells of the upper intestinal tract. Lysozyme is not normally secreted in the lower intestinal tract. Previous reports indicate, however, that lysozyme may be secreted by colorectal neoplasias. The aim was to audit lysozyme expression in colorectal diseases including neoplasias. For that purpose, sections were stained with lysozyme (Muramidase), Ki67 (MIB1) and CD 68. Intense lysozyme overexpression (+++) was compared among 177 colorectal tissues: 35 having normal mucosa, 20 regenerative mucosa in inflammatory bowel disease (IBD), 2 inflammatory polyps, 3 collagenous colitis, 2 melanosis coli, 21 hyperplastic polyps, 42 tubular adenomas, 9 serrated adenomas, 30 villous adenomas and 13 invasive carcinomas. Intense lysozyme overexpression (+++) was found in 9.5% of the hyperplastic polyps, in 97.6% of the tubular adenomas, in 88.9% of the serrated adenomas, in 93.3% of the villous adenomas, in 76.9% of the carcinomas, but in none of the other tissues investigated. Neoplastic colorectal cells may acquire the capacity to produce lysozyme. The presence of that enzyme may not be a haphazard, capricious event in mutated colorectal epithelial cells but part of a more elaborate molecular behavior, not necessarily antibacterial. Recently, it was demonstrated that patients having lysozyme-secreting breast carcinomas were associated with a favorable prognosis. Whether lysozyme expression has any bearing on the biological behavior of colorectal carcinomas remains to be elucidated. Lysozyme overexpression (+++) also occurred in 2 of the 21 hyperplastic polyps, suggesting that intense lysozyme production might herald a possible dysplastic evolution in some hyperplastic polyps.

  14. When is a dose not a dose?

    International Nuclear Information System (INIS)

    Bond, V.P.

    1991-01-01

    Although an enormous amount of progress has been made in the fields of radiation protection and risk assessment, a number of significant problems remain. The one problem which transcends all the rest, and which has been subject to considerable misunderstanding, involves what has come to be known as the 'linear non-threshold hypothesis', or 'linear hypothesis'. Particularly troublesome has been the interpretation that any amount of radiation can cause an increase in the excess incidence of cancer. The linear hypothesis has dominated radiation protection philosophy for more than three decades, with enormous financial, societal and political impacts and has engendered an almost morbid fear of low-level exposure to ionizing radiation in large segments of the population. This document presents a different interpretation of the linear hypothesis. The basis for this view lies in the evolution of dose-response functions, particularly with respect to their use initially in the context of early acute effects, and then for the late effects, carcinogenesis and mutagenesis. 11 refs., 4 figs

  15. Synthetic smoke with acrolein but not HCl produces pulmonary edema.

    Science.gov (United States)

    Hales, C A; Barkin, P W; Jung, W; Trautman, E; Lamborghini, D; Herrig, N; Burke, J

    1988-03-01

    The chemical toxins in smoke and not the heat are responsible for the pulmonary edema of smoke inhalation. We developed a synthetic smoke composed of carbon particles (mean diameter of 4.3 microns) to which toxins known to be in smoke, such as HCl or acrolein, could be added one at a time. We delivered synthetic smoke to dogs for 10 min and monitored extravascular lung water (EVLW) accumulation thereafter with a double-indicator thermodilution technique. Final EVLW correlated highly with gravimetric values (r = 0.93, P less than 0.01). HCl in concentrations of 0.1-6 N when added to heated carbon (120 degrees C) and cooled to 39 degrees C produced airway damage but no pulmonary edema. Acrolein, in contrast, produced airway damage but also pulmonary edema, whereas capillary wedge pressures remained stable. Low-dose acrolein smoke (less than 200 ppm) produced edema in two of five animals with a 2- to 4-h delay. Intermediate-dose acrolein smoke (200-300 ppm) always produced edema at an average of 147 +/- 57 min after smoke, whereas high-dose acrolein (greater than 300 ppm) produced edema at 65 +/- 16 min after smoke. Thus acrolein but not HCl, when presented as a synthetic smoke, produced a delayed-onset, noncardiogenic, and peribronchiolar edema in a roughly dose-dependent fashion.

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

    Science.gov (United States)

    Duong, Phuong-Anh; Little, Brent P

    2014-08-01

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

  17. Risk equivalent of exposure versus dose of radiation

    International Nuclear Information System (INIS)

    Bond, V.P.

    1986-01-01

    This report describes a risk analysis study of low-dose irradiation and the resulting biological effects on a cell. The author describes fundamental differences between the effects of high-level exposure (HLE) and low-level exposure (LLE). He stresses that the concept of absorbed dose to an organ is not a dose but a level of effect produced by a particular number of particles. He discusses the confusion between a linear-proportional representation of dose limits and a threshold-curvilinear representation, suggesting that a LLE is a composite of both systems

  18. Radiochromic Plastic Films for Accurate Measurement of Radiation Absorbed Dose and Dose Distributions

    DEFF Research Database (Denmark)

    McLaughlin, W. L.; Miller, Arne; Fidan, S.

    1977-01-01

    of many polymeric systems in industrial radiation processing. The result is that errors due to energy dependence of response of the radiation sensor are effectively reduced, since the spectral sensitivity of the dose meter matches that of the polymer of interest, over a wide range of photon and electron......Thin radiochromic dye films are useful for measuring large radiation absorbed doses (105–108 rads) and for high-resolution imaging of dose patterns produced by penetrating radiation beams passing through non-homogeneous media. Certain types of amino-substituted triarylmethane cyanides dissolved...... in polymeric solutions can be cast into flexible free-standing thin films of uniform thickness and reproducible response to ultraviolet and ionizing radiation. The increase in optical density versus energy deposited by radiation is linear over a wide range of doses and is for practical purposes independent...

  19. Monitoring of the solar power plants and performance ratio

    Science.gov (United States)

    Sredenšek, Klemen; Šlamberger, Jan; Štumberger, Bojan; Hadžiselimović, Miralem; Seme, Sebastijan

    2017-07-01

    This paper deals with monitoring of solar power plants. We can observe solar power plants with energy yield, monitoring or performance ratio. All these approaches of monitoring solar power plants have their advantages and disadvantages. The procedures of monitoring different solar power plants in Slovenia will be presented and evaluated in the paper. It turns out that energy yield and monitoring of solar power plants don't give enough necessary information concerning proper operation. Energy yield is the ratio between the energy produced and the nominal power of the solar power plant. Energy yield is dependent on the intensity of solar radiation and temperature. It appears that proper operation of solar power plants is best described with the performance ratio, which is the ration between the energy produced and the energy that would be produced at nominal yield. Performance ratio considers the intensity of solar radiation and/or temperature. The results show that the proper operation of the solar power plants is mostly affected by appropriate installation and orientation of solar modules.

  20. Optimal initial dose adjustment of warfarin in orthopedic patients.

    Science.gov (United States)

    Lenzini, Petra A; Grice, Gloria R; Milligan, Paul E; Gatchel, Susan K; Deych, Elena; Eby, Charles S; Burnett, R Stephen J; Clohisy, John C; Barrack, Robert L; Gage, Brian F

    2007-11-01

    Warfarin sodium is commonly prescribed for the prophylaxis and treatment of venous thromboembolism. Dosing algorithms have not been widely adopted because they require a fixed initial warfarin dose (eg, 5 mg) and are not tailored to other factors that may affect the international normalized ratio (INR). To develop an algorithm that could predict a therapeutic warfarin dose based on drug interactions, INR response after the initial warfarin doses, and other clinical factors. We used stepwise regression to quantify the relationship between these factors in patients beginning prophylactic warfarin therapy immediately prior to joint replacement. In the derivation cohort (n = 271), we separately modeled the therapeutic dose after 2 and 3 initial doses. We prospectively validated these 2 models in an independent cohort (n = 105). About half of the therapeutic dose variability was predictable after 3 days of therapy: R2 was 53% in the derivation cohort and 42% in the validation cohort. INR response after 3 warfarin doses (INR3) inversely correlated with therapeutic dose (p < 0.001). Intraoperative blood loss transiently, but significantly, elevated the postoperative INR values. Other significant (p < 0.03) predictors were the first and second warfarin doses (+7% and +6%, respectively, per 1 mg), and statin use (-15.0%). The model derived after 2 warfarin doses explained 32% of the variability in therapeutic dose. We developed and validated algorithms that estimate therapeutic warfarin doses based on clinical factors and INR response available after 2-3 days of warfarin therapy. The algorithms are implemented online at www.WarfarinDosing.org.

  1. Health literacy predicts pediatric dosing accuracy for liquid zidovudine.

    Science.gov (United States)

    Howard, Leigh M; Tique, José A; Gaveta, Sandra; Sidat, Mohsin; Rothman, Russell L; Vermund, Sten H; Ciampa, Philip J

    2014-04-24

    Little is known about adult caregivers' ability to accurately dose pediatric antiretroviral medications. We aimed to characterize the frequency of dosing errors for liquid zidovudine using two dosing devices and to evaluate the association between HIV literacy and dosing errors in adults living with HIV infection. Cross-sectional study enrolling 316 adults receiving combination antiretroviral therapy (cART) for HIV infection in Maputo Province, Mozambique. Participants were administered the HIV Literacy Test (HIV-LT) and asked to measure 2.5 ml of liquid zidovudine using both a cup and syringe. Dosing measurement errors for liquid zidovudine were defined as 'any error' (≥ 20% deviation from reference dose) and 'major error' (≥ 40% deviation from reference dose). Dosing errors were common using the cup (any error: 50%, major error: 28%) and syringe (any error: 48% of participants, major error: 28%). There were no significant differences in proportions of any dosing error (P=0.61) or major dosing errors (P=0.82) between dosing instruments. In multivariable models, associations (P ≤ 0.03) were found between higher HIV-LT score and dosing errors for both the cup [any error adjusted odds ratio, AOR: 0.91 (0.84-0.99), major error AOR: 0.84 (0.75-0.92)] and syringe [any error AOR: 0.82 (0.75-0.90), major error AOR: 0.88 (0.80-0.97)]. Liquid antiretroviral medications are critical for prevention and treatment of pediatric HIV infections, yet dosing errors were exceedingly common in this population and were significantly associated with lower HIV literacy levels. Targeted interventions are needed to improve HIV knowledge and skills for pediatric medication dosing, particularly for caregivers with limited literacy.

  2. Development of Producibility Evaluation Criteria

    National Research Council Canada - National Science Library

    Wilkins, Jr., James R; Kraine, Gilbert L; Thompson, Daniel H; Borchers, Kenneth H; Borchers, Marilyn M

    1993-01-01

    .... To accept this definition is to equate producibility with productivity, and normally leads to consideration of many more elements than should be taken into account for evaluating producibility...

  3. Minimum monitor unit per segment IMRT planning and over-shoot-ratio

    International Nuclear Information System (INIS)

    Grigorov, G.; Barnett, R.; Chow, J.

    2004-01-01

    The aim of this work is to describe the modulation quality for dose delivery of small Multi-Leaf Collimator (MLC) fields and MU/segment. The results were obtained with Pinnacle (V6) and a Varian Clinac 2100 EX (Varis 6.2) linear accelerator. The over-shoot effect was investigated by comparing integrated multiple segmented exposures to a single exposure with the same number of total MU (1, 2, 3,4, 5 and 6 MU). To present the OS effect the Over-Shoot-Ratio (OSR) was defined as the ratio of the segmented dose for a 1 cm 2 field at depth to the static dose for the same field size and depth. OSR was measured as a function of MU/segment and dose rate. Measured results can be used to optimise IMRT planning and also to calculate the surface dose. The dependence of the dose in depth with 1, 2, 3, 4, and 5 MU/segments for 6 MV photon beam, dose rate of 100 MU/min and 1 cm 2 beam field at the central axis is presented, where the argument of the function is the depth and parameter of the function is the number of minimum MU/segment. The dependence of the overshoot ratio on the MU/segment with a parameter of the dose rates (100, 400 and 600 MU/min) is also shown. The effect increases with the dose rate and decreases with the increasing of the minimum number of MU/segment. Having measured OSR for the 2100 EX linac it is possible to do correction and calibration of the dose of the first segment of IMRT beam, where the dose to the target and on the surface can increase over the planed dose of 1 MU by 40% and 70% for dose rate of 400 and 600 MU/min respectively. The Over-Shoot-Ratio is an important parameter to be determined as part of the routine quality assurance for IMRT and can be used to significantly improve the agreement between planned and delivered doses to the patient

  4. Radiation dose optimization in thoracic imaging

    OpenAIRE

    Tack, D

    2010-01-01

    Guidelines for reduction of CT radiation dose were introduced in 1997 and are now more than 12 years old. The process initiated by the European Regulatory authorities to reduce the excess of radiation from CT has however not produced the expected results. Reference diagnostic levels (DRL) from surveys are still twice as high as needed in most European countries and were not significantly reduced as compared to the initial European ones. Many factors may at least explain partially the lack of ...

  5. Tumor significant dose

    International Nuclear Information System (INIS)

    Supe, S.J.; Nagalaxmi, K.V.; Meenakshi, L.

    1983-01-01

    In the practice of radiotherapy, various concepts like NSD, CRE, TDF, and BIR are being used to evaluate the biological effectiveness of the treatment schedules on the normal tissues. This has been accepted as the tolerance of the normal tissue is the limiting factor in the treatment of cancers. At present when various schedules are tried, attention is therefore paid to the biological damage of the normal tissues only and it is expected that the damage to the cancerous tissues would be extensive enough to control the cancer. Attempt is made in the present work to evaluate the concent of tumor significant dose (TSD) which will represent the damage to the cancerous tissue. Strandquist in the analysis of a large number of cases of squamous cell carcinoma found that for the 5 fraction/week treatment, the total dose required to bring about the same damage for the cancerous tissue is proportional to T/sup -0.22/, where T is the overall time over which the dose is delivered. Using this finding the TSD was defined as DxN/sup -p/xT/sup -q/, where D is the total dose, N the number of fractions, T the overall time p and q are the exponents to be suitably chosen. The values of p and q are adjusted such that p+q< or =0.24, and p varies from 0.0 to 0.24 and q varies from 0.0 to 0.22. Cases of cancer of cervix uteri treated between 1978 and 1980 in the V. N. Cancer Centre, Kuppuswamy Naidu Memorial Hospital, Coimbatore, India were analyzed on the basis of these formulations. These data, coupled with the clinical experience, were used for choice of a formula for the TSD. Further, the dose schedules used in the British Institute of Radiology fraction- ation studies were also used to propose that the tumor significant dose is represented by DxN/sup -0.18/xT/sup -0.06/

  6. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities.

    Science.gov (United States)

    Lechuga, Lawrence; Weidlich, Georg A

    2016-09-12

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities-fan beam and cone beam-was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient.

  7. Low dose radiation exposure and atherosclerosis in ApoE-/- mice

    International Nuclear Information System (INIS)

    Mitchel, R.E.J.; Hasu, M.; Bugden, M.; Wyatt, H.; Little, M.; Hildebrandt, G.; Priest, N.D.; Whitman, S.C.

    2010-01-01

    The hypothesis that single low dose exposures (0.025-0.5 Gy) to low LET radiation, given at either high (240 mGy/min) or low (1 mGy/min) dose rate, would promote aortic atherosclerosis was tested in female C57BI/6 mice genetically predisposed to this disease (ApoE-/-). Mice were exposed either at early stage disease (2 months of age) and examined 3 or 6 months later, or at late stage disease (8 months of age) and examined 2 or 4 months later. Compared to unexposed controls, all doses given at low or high dose rate at early stage disease had significant inhibitory effects on lesion growth and, at 25 or 50 mGy, on lesion frequency. No dose given at low dose rate had any effect on total serum cholesterol, but this was elevated by every dose given at high dose rate. Exposures at low dose rate had no effect on the percentage of lesion lipids contained within macrophages, and, at either high or low dose rate, had no significant effect on lesion severity. Exposure at late stage disease, to any dose at high dose rate, had no significant effect on lesion frequency, but at low dose rate some doses produced a small transient increase in this frequency. Exposure to low doses at low, but not high dose rate, significantly, but transiently reduced average lesion size, and at either dose rate transiently reduced lesion severity. Exposure to any dose at low dose rate (but not high dose rate) resulted in large and persistent decreases in serum cholesterol. These data indicate that a single low dose exposure, depending on dose and dose rate, generally protects against various measures of atherosclerosis in genetically susceptible mice. This result contrasts with the known, generally detrimental effects of high doses on this disease in the same mice, suggesting that a linear extrapolation of risk from high doses is not appropriate. (author)

  8. Power Producer Production Valuation

    Directory of Open Access Journals (Sweden)

    M. Kněžek

    2008-01-01

    Full Text Available The ongoing developments in the electricity market, in particular the establishment of the Prague Energy Exchange (PXE and the associated transfer from campaign-driven sale to continuous trading, represent a significant change for power companies.  Power producing companies can now optimize the sale of their production capacities with the objective of maximizing profit from wholesale electricity and supporting services. The Trading Departments measure the success rate of trading activities by the gross margin (GM, calculated by subtracting the realized sales prices from the realized purchase prices and the production cost, and indicate the profit & loss (P&L to be subsequently calculated by the Control Department. The risk management process is set up on the basis of a business strategy defining the volumes of electricity that have to be sold one year and one month before the commencement of delivery. At the same time, this process defines the volume of electricity to remain available for spot trading (trading limits. 

  9. Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice

    International Nuclear Information System (INIS)

    Ware, J.H.; Rusek, A.; Sanzari, J.; Avery, S.; Sayers, C.; Krigsfeld, G.; Nuth, M.; Wan, X.S.; Kennedy, A.R.

    2010-01-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

  10. Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice.

    Science.gov (United States)

    Ware, J H; Sanzari, J; Avery, S; Sayers, C; Krigsfeld, G; Nuth, M; Wan, X S; Rusek, A; Kennedy, A R

    2010-09-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

  11. An assessment of effective dose to staff in external beam radiotherapy

    International Nuclear Information System (INIS)

    Rawlings, D.J.; Nicholson, L.

    1997-01-01

    Radiation safety in external beam radiotherapy is governed by national legislation. Annual doses recorded by radiographers and others associated with external beam radiotherapy are typically much lower than the relevant dose limit. However, it is possible that larger doses might be received as a result of an accidental irradiation. In the event of a significant exposure resulting in a dose at or near a relevant dose limit, an accurate conversion has to be made from the dose meter reading to the limiting quantity. A method was devised to demonstrate ratios of effective dose to personal dose equivalent which might be anticipated in the even of an individual other than the patient being irradiated within a radiotherapy treatment room consisting of a linear accelerator. The variation of ratios obtained under different conditions is discussed. (author)

  12. Improved penetration from spectral hardening of reactor produced epithermal neutron beams using 6Li filtration

    International Nuclear Information System (INIS)

    Binns, P.J.; Riley, K.J.; Kiger, W.S. III; Harling, O.K.

    2006-01-01

    The use of an optional 6 Li-filter in a clinical epithermal neutron beam was studied using Monte Carlo calculations of the fission converter beam (FCB) and radiation transport through an ellipsoidal water phantom. The design premise was to produce a beam with the highest possible advantage depth (AD) while also maximizing the advantage depth dose rate (ADDR) and advantage ratio (AR). This was achieved by spectral modification using a 6 Li-filter 8 mm thick that preferentially removes neutrons of the lowest energies in the epithermal range. Predicted gains in beam performance were confirmed by measurement and are greater for smaller field sizes. An increase of 6 mm in the AD to 9.9 cm with a concomitant loss in beam intensity of 52% was realized with the 12 cm diameter field. (author)

  13. A patient dose survey for femoral arteriogram diagnostic radiographic examinations using a dose-area product meter

    International Nuclear Information System (INIS)

    Thwaites, J.H.; Rafferty, M.W.; Gray, N.; Black, J.; Stock, B.

    1996-01-01

    A patient dose survey was carried out for femoral arteriogram procedures at the Sir Charles Gairdner Hospital. The procedure involves fluoroscopy to the pelvic region to locate a guide wire and catheter, followed by a series of radiographs extending from the pelvic area to the feet to form a collage image of the entire arterial system. Radiographs are taken whilst a bolus of contrast media is injected into the arterial system. A dose-area product meter was used to determine the dose-area product delivered to patients. Radiographic and patient details were logged with dose-area product for each part of each procedure. Mean energy imparted, mean effective dose and effective dose equivalent are calculated for the examinations. Calculated effective doses are shown to produce results consistent with those of other authors. We present a method for dealing with a complex radiographic procedure including multiple radiographs and fluoroscopy in an attempt to provide a simple way of calculating effective dose from which a general risk factor can be determined. The effective dose varies considerably from examination to examination due to the large range in the number of radiographs taken in any one procedure. A useful index can be obtained by logging the number of radiographs in each region, and fluoroscopy time, from which the effective dose may be easily calculated. These measurements extend a continuing survey of doses for common diagnostic radiographic examinations which previously included the simple examinations: lumbar spine, abdoment and pelvis. (author)

  14. Warfarin Dosing Algorithms Underpredict Dose Requirements in Patients Requiring ≥7 mg Daily: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    Saffian, S M; Duffull, S B; Wright, Dfb

    2017-08-01

    There is preliminary evidence to suggest that some published warfarin dosing algorithms produce biased maintenance dose predictions in patients who require higher than average doses. We conducted a meta-analysis of warfarin dosing algorithms to determine if there exists a systematic under- or overprediction of dose requirements for patients requiring ≥7 mg/day across published algorithms. Medline and Embase databases were searched up to September 2015. We quantified the proportion of over- and underpredicted doses in patients whose observed maintenance dose was ≥7 mg/day. The meta-analysis included 47 evaluations of 22 different warfarin dosing algorithms from 16 studies. The meta-analysis included data from 1,492 patients who required warfarin doses of ≥7 mg/day. All 22 algorithms were found to underpredict warfarin dosing requirements in patients who required ≥7 mg/day by an average of 2.3 mg/day with a pooled estimate of underpredicted doses of 92.3% (95% confidence interval 90.3-94.1, I 2 = 24%). © 2017 American Society for Clinical Pharmacology and Therapeutics.

  15. Influence of the effective acceleration ratio on the changes in characteristics of low-voltage cables by combined heat-radiation aging

    International Nuclear Information System (INIS)

    Okamoto, Shinichi; Ohnishi, Tokuhiro; Ueda, Yoshihiro; Tanaka, Takuo.

    1994-01-01

    The changes in the characteristics (insulation resistance, tensile strength, elongation, hardness, 10-mm and 20-mm bending load, and torsional torque) of low-voltage cables used in nuclear power plants were studied after simultaneous exposure to heat and ionizing radiation. The heat applied was high temperature atmospheres, which were of 107, 118 and 130degC. These three temperatures were found in a preliminary experiment to produce 100, 300 and 1000 times of effects (effective acceleration ratios) caused by thermal aging at 60degC. The ionizing radiation used was 60 Co γ-rays, which had dose rates of 100, 300 and 1000 times of average dose rate of 1.5 Gy/hr expected at normal operation of nuclear power plants. It was found that at low effective acceleration ratios (for heat and ionizing radiation) the deterioration of the jacketing and insulating materials of low-voltage cables was more severe than that at high effective acceleration ratios. The possibility was studied of nondestructive methods for the life evaluation of low-voltage cables combined heat-radiation accelerated aging, and the cable hardness test, the bending test and the torsion test were found to be applicable. (author)

  16. Entrance surface dose according to dose calculation: Head and wrist

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Ho Jin [Dept. Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Han, Jae Bok; Song, Jong Nam; Choi, Nam Gil [Dept. of Radiological Science, Dongshin University, Naju (Korea, Republic of)

    2016-09-15

    This study were compared with the direct measurement and indirect dose methods through various dose calculation in head and wrist. And, the modified equation was proposed considering equipment type, setting conditions, tube voltage, inherent filter, added filter and its accompanied back scatter factor. As a result, it decreased the error of the direct measurement than the existing dose calculation. Accordingly, diagnostic radiography patient dose comparison would become easier and radiographic exposure control and evaluation will become more efficient. The study findings are expected to be useful in patients' effective dose rate evaluation and dose reduction.

  17. Occupational dose assessment and national dose registry system in Iran

    International Nuclear Information System (INIS)

    Jafari-Zadeh, M.; Nazeri, F.; Hosseini-Pooya, S. M.; Taheri, M.; Gheshlaghi, F.; Kardan, M. R.; Babakhani, A.; Rastkhah, N.; Yousefi-Nejad, F.; Darabi, M.; Oruji, T.; Gholamali-Zadeh, Z.; Karimi-Diba, J.; Kazemi-Movahed, A. A.; Dashti-Pour, M. R.; Enferadi, A.; Jahanbakhshian, M. H.; Sadegh-Khani, M. R.

    2011-01-01

    This report presents status of external and internal dose assessment of workers and introducing the structure of National Dose Registry System of Iran (NDRSI). As well as types of individual dosemeters in use, techniques for internal dose assessment are presented. Results obtained from the International Atomic Energy Agency intercomparison programme on measurement of personal dose equivalent H p (10) and consistency of the measured doses with the delivered doses are shown. Also, implementation of dosimetry standards, establishment of quality management system, authorisation and approval procedure of dosimetry service providers are discussed. (authors)

  18. Organ dose estimates for the Japanese atomic-bomb survivors

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, G.D.

    1978-10-01

    Recent studies concerning radiation risks to man by the Committee on Biological Effects of Ionizing Radiation of the National Academy of Sciences-National Research Council and the United Nations Scientific Committee on the Effects of Atomic Radiation have emphasized the need for estimates of dose to organs of the Japanese atomic-bomb survivors. Shielding of internal organs by the body has been investigated for fission-weapon gamma rays and neutrons, and ratios of mean absorbed dose in a number of organs to survivors' T65D assignments of tissue kerma in air are provided for adults. Ratios of mean absorbed dose to tissue kerma in air are provided also for the thyroid and active bone marrow of juveniles. These organ dose estimates for juveniles are of interest in studies of radiation risks due to an elevated incidence of leukemia and thyroid cancer in survivors exposed as children compared to survivors exposed as adults.

  19. Organ dose estimates for the Japanese atomic-bomb survivors

    International Nuclear Information System (INIS)

    Kerr, G.D.

    1978-10-01

    Recent studies concerning radiation risks to man by the Committee on Biological Effects of Ionizing Radiation of the National Academy of Sciences-National Research Council and the United Nations Scientific Committee on the Effects of Atomic Radiation have emphasized the need for estimates of dose to organs of the Japanese atomic-bomb survivors. Shielding of internal organs by the body has been investigated for fission-weapon gamma rays and neutrons, and ratios of mean absorbed dose in a number of organs to survivors' T65D assignments of tissue kerma in air are provided for adults. Ratios of mean absorbed dose to tissue kerma in air are provided also for the thyroid and active bone marrow of juveniles. These organ dose estimates for juveniles are of interest in studies of radiation risks due to an elevated incidence of leukemia and thyroid cancer in survivors exposed as children compared to survivors exposed as adults

  20. Validation of a dual-isotope plasma ratio method for measurement of cholesterol absorption in rats.

    Science.gov (United States)

    Zilversmit, D B; Hughes, L B

    1974-09-01

    Several methods for measuring cholesterol absorption in the rat have been compared. After administration of an oral dose of labeled cholesterol ((14)C or (3)H) and an intravenous dose of colloidal labeled cholesterol ((3)H or (14)C) the ratio of the two labels in plasma or whole blood 48 hr or more after dosing compared closely to the ratio of areas under the respective specific activity-time curves. The area ratio method is independent of a time lag between the appearance of oral and intravenous label in the bloodstream. Both measures of cholesterol absorption agree fairly well with a method based on measuring the unabsorbed dietary cholesterol in a pooled fecal sample. The plasma isotope ratio method gave more reproducible results than the fecal collection method when the measurement was repeated in the same animals 5 days after the first measurement. Cholesterol absorption was overestimated by the use of Tween 20-solubilized labeled cholesterol for the intravenous dose. The plasma disappearance curves of injected labeled colloidal cholesterol and cholesterol-labeled chylomicrons infused intravenously over a 3.5-hr period in the same animal coincided within experimental error from the first day until 75 days after injection. The plasma isotope ratio method for cholesterol absorption gave the same results in rats practicing coprophagy as in those in which this practice was prevented. The addition of sulfaguanidine to the diet lowered cholesterol absorption as measured by the plasma isotope ratio to the same degree as that measured by the fecal collection method.

  1. Absorbed Doses to Patients in Nuclear Medicine

    International Nuclear Information System (INIS)

    Leide-Svegborn, Sigrid; Mattsson, Soeren; Nosslin, Bertil; Johansson, Lennart

    2004-09-01

    The work with a Swedish catalogue of radiation absorbed doses to patients undergoing nuclear medicine investigations has continued. After the previous report in 1999, biokinetic data and dose estimates (mean absorbed dose to various organs and tissues and effective dose) have been produced for a number of substances: 11 C- acetate, 11 C- methionine, 18 F-DOPA, whole antibody labelled with either 99m Tc, 111 In, 123 I or 131 I, fragment of antibody, F(ab') 2 labelled with either 99m Tc, 111 In, 123 I or 131 I and fragment of antibody, Fab' labelled with either 99m Tc, 111 In, 123 I or 131 I. The absorbed dose estimates for these substances have been made from published biokinetic information. For other substances of interest, e.g. 14 C-urea (children age 3-6 years), 14 C-glycocholic acid, 14 C-xylose and 14 C-triolein, sufficient literature data have not been available. Therefore, a large number of measurements on patients and volunteers have been carried out, in order to determine the biokinetics and dosimetry for these substances. Samples of breast milk from 50 mothers, who had been subject to nuclear medicine investigations, have been collected at various times after administration of the radiopharmaceutical to the mother. The activity concentration in the breast milk samples has been measured. The absorbed dose to various organs and tissues and the effective dose to the child who ingests the milk have been determined for 17 different radiopharmaceuticals. Based on these results revised recommendations for interruption of breast-feeding after nuclear medicine investigations are suggested

  2. Doses from radiation exposure

    CERN Document Server

    Menzel, H G

    2012-01-01

    Practical implementation of the International Commission on Radiological Protection's (ICRP) system of protection requires the availability of appropriate methods and data. The work of Committee 2 is concerned with the development of reference data and methods for the assessment of internal and external radiation exposure of workers and members of the public. This involves the development of reference biokinetic and dosimetric models, reference anatomical models of the human body, and reference anatomical and physiological data. Following ICRP's 2007 Recommendations, Committee 2 has focused on the provision of new reference dose coefficients for external and internal exposure. As well as specifying changes to the radiation and tissue weighting factors used in the calculation of protection quantities, the 2007 Recommendations introduced the use of reference anatomical phantoms based on medical imaging data, requiring explicit sex averaging of male and female organ-equivalent doses in the calculation of effecti...

  3. Small dose... big poison.

    Science.gov (United States)

    Braitberg, George; Oakley, Ed

    2010-11-01

    It is not possible to identify all toxic substances in a single journal article. However, there are some exposures that in small doses are potentially fatal. Many of these exposures are particularly toxic to children. Using data from poison control centres, it is possible to recognise this group of exposures. This article provides information to assist the general practitioner to identify potential toxic substance exposures in children. In this article the authors report the signs and symptoms of toxic exposures and identify the time of onset. Where clear recommendations on the period of observation and known fatal dose are available, these are provided. We do not discuss management or disposition, and advise readers to contact the Poison Information Service or a toxicologist for this advice.

  4. First dose in man

    DEFF Research Database (Denmark)

    Hougaard Christensen, Mette Marie

    2011-01-01

    Du er blevet ansat som læge i et lægemiddelfirma med ansvar for planlægning og sikkerhed i fase 1 forsøg. Firmaet har udviklet tre dopamin D2-receptor antagonister til behandling af skizofreni. Lægemidlerne har undergået et omfattende farmakologisk, toksikologisk og farmaceutisk afprøvningsprogra...... fase 1 forsøg alias »First dose in man«....

  5. Absorbed dose from traversing spherically symmetric, Gaussian radioactive clouds

    International Nuclear Information System (INIS)

    Thompson, J.M.; Poston, J.W.

    1999-01-01

    If a large radioactive cloud is produced, sampling may require that an airplane traverse the cloud. A method to predict the absorbed dose to the aircrew from penetrating the radioactive cloud is needed. Dose rates throughout spherically symmetric Gaussian clouds of various sizes, and the absorbed doses from traversing the clouds, were calculated. Cloud size is a dominant parameter causing dose to vary by orders of magnitude for a given dose rate measured at some distance. A method to determine cloud size, based on dose rate readings at two or more distances from the cloud center, was developed. This method, however, failed to resolve the smallest cloud sizes from measurements made at 1,000 m to 2,000 m from the cloud center

  6. Terrestrial gamma dose rate in Pahang state Malaysia

    International Nuclear Information System (INIS)

    Gabdo, H.T.; Federal College of Education, Yola; Ramli, A.T.; Sanusi, M.S.; Saleh, M.A.; Garba, N.N.; Ahmadu Bello University, Zaria

    2014-01-01

    Environmental terrestrial gamma radiations (TGR) were measured in Pahang state Malaysia between January and April 2013. The TGR dose rates ranged from 26 to 750 nGy h -1 . The measurements were done based on geology and soil types of the area. The mean TGR dose rate was found to be 176 ± 5 nGy h -1 . Few areas of relatively enhanced activity were located in Raub, Temerloh, Bentong and Rompin districts. These areas have external gamma dose rates of between 500 and 750 nGy h -1 . An Isodose map of the state was produced using ArcGIS9 software version 9.3. To evaluate the radiological hazard due to terrestrial gamma dose, the annual effective dose equivalent and the mean population weighted dose rate were calculated and found to be 0.22 mSv year -1 and 168 nGy h -1 respectively. (author)

  7. Peripheral doses of cranial pediatric IMRT performed with attenuator blocks

    International Nuclear Information System (INIS)

    Soboll, Danyel Scheidegger; Schitz, Ivette; Schelin, Hugo Reuters; Silva, Ricardo Goulart da; Viamonte, Alfredo

    2011-01-01

    This paper presents values of peripheral doses measured at six vital points of simulator objects which represent the ages of 2, 5 and 10 years old, submitted to a cranial IMRT procedure that applied compensator blocks interposed to 6 MV beams. The found values indicate that there is independence of dose with position of measurements and age of the patient, as the peripheral dose at the points nearest and the 2 year old simulator object where larger. The doses in thyroid reached the range of 1.4 to 2.9% of the dose prescribed in the isocenter, indicating that the peripheral doses for IMRT that employ compensator blocks can be greater than for the IMRT produced with sliding window technique

  8. Cone beam CT with zonal filters for simultaneous dose reduction, improved target contrast and automated set-up in radiotherapy

    International Nuclear Information System (INIS)

    Moore, C J; Marchant, T E; Amer, A M

    2006-01-01

    Cone beam CT (CBCT) using a zonal filter is introduced. The aims are reduced concomitant imaging dose to the patient, simultaneous control of body scatter for improved image quality in the tumour target zone and preserved set-up detail for radiotherapy. Aluminium transmission diaphragms added to the CBCT x-ray tube of the Elekta Synergy TM linear accelerator produced an unattenuated beam for a central 'target zone' and a partially attenuated beam for an outer 'set-up zone'. Imaging doses and contrast noise ratios (CNR) were measured in a test phantom for transmission diaphragms 12 and 24 mm thick, for 5 and 10 cm long target zones. The effect on automatic registration of zonal CBCT to conventional CT was assessed relative to full-field and lead-collimated images of an anthropomorphic phantom. Doses along the axis of rotation were reduced by up to 50% in both target and set-up zones, and weighted dose (two thirds surface dose plus one third central dose) was reduced by 10-20% for a 10 cm long target zone. CNR increased by up to 15% in zonally filtered CBCT images compared to full-field images. Automatic image registration remained as robust as that with full-field images and was superior to CBCT coned down using lead-collimation. Zonal CBCT significantly reduces imaging dose and is expected to benefit radiotherapy through improved target contrast, required to assess target coverage, and wide-field edge detail, needed for robust automatic measurement of patient set-up error

  9. Dose calculation for electrons

    International Nuclear Information System (INIS)

    Hirayama, Hideo

    1995-01-01

    The joint working group of ICRP/ICRU is advancing the works of reviewing the ICRP publication 51 by investigating the data related to radiation protection. In order to introduce the 1990 recommendation, it has been demanded to carry out calculation for neutrons, photons and electrons. As for electrons, EURADOS WG4 (Numerical Dosimetry) rearranged the data to be calculated at the meeting held in PTB Braunschweig in June, 1992, and the question and request were presented by Dr. J.L. Chartier, the responsible person, to the researchers who are likely to undertake electron transport Monte Carlo calculation. The author also has carried out the requested calculation as it was the good chance to do the mutual comparison among various computation codes regarding electron transport calculation. The content that the WG requested to calculate was the absorbed dose at depth d mm when parallel electron beam enters at angle α into flat plate phantoms of PMMA, water and ICRU4-element tissue, which were placed in vacuum. The calculation was carried out by the versatile electron-photon shower computation Monte Carlo code, EGS4. As the results, depth dose curves and the dependence of absorbed dose on electron energy, incident angle and material are reported. The subjects to be investigated are pointed out. (K.I.)

  10. SPECIAL CONSIDERATIONS REGARDING WARFARIN DOSE TITRATION IN PATIENTS WITH ATRIAL FIBRILLATION DEPENDING ON CLINICAL FACTORS

    OpenAIRE

    E. L. Artanova; E. V. Saleeva; I. M. Sokolov; Y. G. Shvarts

    2011-01-01

    Aim. To study the relations of clinical characteristics and individual warfarin dose titration in patients with atrial fibrillation. Material and methods. Period of warfarin dose titration was analyzed in 68 patients with atrial fibrillation due to ischemic heart disease. Adjusted warfarin dose in milligram, duration of dose titration in days and maximal international normalized ratio (INR) were taken into account. Sex, age, history of myocardial infarction and stroke, concomitant diseases, a...

  11. Comparison of two dose and three dose human papillomavirus vaccine schedules: cost effectiveness analysis based on transmission model.

    Science.gov (United States)

    Jit, Mark; Brisson, Marc; Laprise, Jean-François; Choi, Yoon Hong

    2015-01-06

    To investigate the incremental cost effectiveness of two dose human papillomavirus vaccination and of additionally giving a third dose. Cost effectiveness study based on a transmission dynamic model of human papillomavirus vaccination. Two dose schedules for bivalent or quadrivalent human papillomavirus vaccines were assumed to provide 10, 20, or 30 years' vaccine type protection and cross protection or lifelong vaccine type protection without cross protection. Three dose schedules were assumed to give lifelong vaccine type and cross protection. United Kingdom. Males and females aged 12-74 years. No, two, or three doses of human papillomavirus vaccine given routinely to 12 year old girls, with an initial catch-up campaign to 18 years. Costs (from the healthcare provider's perspective), health related utilities, and incremental cost effectiveness ratios. Giving at least two doses of vaccine seems to be highly cost effective across the entire range of scenarios considered at the quadrivalent vaccine list price of £86.50 (€109.23; $136.00) per dose. If two doses give only 10 years' protection but adding a third dose extends this to lifetime protection, then the third dose also seems to be cost effective at £86.50 per dose (median incremental cost effectiveness ratio £17,000, interquartile range £11,700-£25,800). If two doses protect for more than 20 years, then the third dose will have to be priced substantially lower (median threshold price £31, interquartile range £28-£35) to be cost effective. Results are similar for a bivalent vaccine priced at £80.50 per dose and when the same scenarios are explored by parameterising a Canadian model (HPV-ADVISE) with economic data from the United Kingdom. Two dose human papillomavirus vaccine schedules are likely to be the most cost effective option provided protection lasts for at least 20 years. As the precise duration of two dose schedules may not be known for decades, cohorts given two doses should be closely

  12. Parental investment, sexual selection and sex ratios.

    Science.gov (United States)

    Kokko, Hanna; Jennions, Michael D

    2008-07-01

    Conventional sex roles imply caring females and competitive males. The evolution of sex role divergence is widely attributed to anisogamy initiating a self-reinforcing process. The initial asymmetry in pre-mating parental investment (eggs vs. sperm) is assumed to promote even greater divergence in post-mating parental investment (parental care). But do we really understand the process? Trivers [Sexual Selection and the Descent of Man 1871-1971 (1972), Aldine Press, Chicago] introduced two arguments with a female and male perspective on whether to care for offspring that try to link pre-mating and post-mating investment. Here we review their merits and subsequent theoretical developments. The first argument is that females are more committed than males to providing care because they stand to lose a greater initial investment. This, however, commits the 'Concorde Fallacy' as optimal decisions should depend on future pay-offs not past costs. Although the argument can be rephrased in terms of residual reproductive value when past investment affects future pay-offs, it remains weak. The factors likely to change future pay-offs seem to work against females providing more care than males. The second argument takes the reasonable premise that anisogamy produces a male-biased operational sex ratio (OSR) leading to males competing for mates. Male care is then predicted to be less likely to evolve as it consumes resources that could otherwise be used to increase competitiveness. However, given each offspring has precisely two genetic parents (the Fisher condition), a biased OSR generates frequency-dependent selection, analogous to Fisherian sex ratio selection, that favours increased parental investment by whichever sex faces more intense competition. Sex role divergence is therefore still an evolutionary conundrum. Here we review some possible solutions. Factors that promote conventional sex roles are sexual selection on males (but non-random variance in male mating success

  13. Effects of different doses of testosterone on gonadotropins, 25-hydroxyvitamin D3, and blood lipids in healthy men

    Directory of Open Access Journals (Sweden)

    Gårevik N

    2014-12-01

    Full Text Available Nina Gårevik, Anders Rane, Linda Björkhem-Bergman, Lena Ekström Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden Aims: To study the effect and time profile of different doses of testosterone enanthate on the blood lipid profile and gonadotropins. Experimental design: Twenty-five healthy male volunteers aged 27–43 years were given 500 mg, 250 mg, and 125 mg of testosterone enanthate as single intramuscular doses of Testoviron® Depot. Luteinizing hormone (LH, follicle-stimulating hormone (FSH, blood lipid profile (total cholesterol, plasma [p-] low-density lipoprotein, p-high-density lipoprotein [HDL], p-apolipoprotein A1 [ApoA1], p-apolipoprotein B, p-triglycerides, p-lipoprotein(a, serum [s-] testosterone, and 25-hydroxyvitamin D3 were analyzed prior to, and 4 and 14 days after dosing. Testosterone and epitestosterone in urine (testosterone/epitestosterone ratio were analyzed prior to each dose after a washout period of 6–8 weeks. Results and discussion: All doses investigated suppressed the LH and FSH concentrations in serum. LH remained suppressed 6 weeks after the 500 mg dose. These results indicate that testosterone has a more profound endocrine effect on the hypothalamic–pituitary–gonadal axis than was previously thought. There was no alteration in 25-hydroxyvitamin D3 levels after testosterone administration compared to baseline levels. The 250 and 500 mg doses induced decreased concentrations of ApoA1 and HDL, whereas the lowest dose (125 mg did not have any effect on the lipid profile. Conclusion: The single doses of testosterone produced a dose-dependent increase in serum testosterone concentrations together with suppression of s-LH and s-FSH. Alterations in ApoA1 and HDL were observed after the two highest single doses. It is possible that long-time abuse of anabolic androgenic steroids will lead to alteration in vitamin D status

  14. In vitro and in vivo effects of low dose HTO contamination modulated by dose rate

    International Nuclear Information System (INIS)

    Petcu, I.; Savu, D.; Moisoi, N.; Koeteles, G.J.

    1997-01-01

    The experiment performed in vitro intended to examine whether an adaptive response could be elicited on lymphocytes by low-level contamination of whole blood with tritiated water and if the modification of the dose rate has any influence on it. Lymphocytes pre-exposed to 3 HOH (0.2 - 6.6 MBq/ml) and subsequently irradiated with I Gy γ-rays showed micronuclei frequency significantly lower (40% - 45%) than the expected member (sum of the yields induced by 3 HOH and γ-rays separately). The degree of the radioresistance induced by HTO pre-treatments became higher with decreasing dose-rate for a rather similar total adapting dose. In vivo, the aim of the study was to investigate if different dose rates are inducing modulation of the lipid peroxidation level and of the thymidine uptake in different tissues of animals contaminated by HTO ingestion. The total doses varied between 5 and 20 cGy and were delivered as chronic (100 days) or acute contamination (5 days). It was observed that only doses about 20 cGy caused a dose-rate dependent increase of the lipid peroxidation level in the tissues of small intestine, kidney and spleen. Both chronic and acute contamination did produce reduced incorporation of thymidine in the cells of bone marrow. The most effective decrease of thymidine uptake was induced by the acute contamination in the lower dose domain (approx. 5 cGy). Our hypothesis is that in this dose domain the modification of thymidine uptake could be due to changes at the level of membrane transport. (author)

  15. Development of Real-Time Measurement of Effective Dose for High Dose Rate Neutron Fields

    International Nuclear Information System (INIS)

    Braby, L. A.; Reece, W. D.; Hsu, W. H.

    2003-01-01

    Studies of the effects of low doses of ionizing radiation require sources of radiation which are well characterized in terms of the dose and the quality of the radiation. One of the best measures of the quality of neutron irradiation is the dose mean lineal energy. At very low dose rates this can be determined by measuring individual energy deposition events, and calculating the dose mean of the event size. However, at the dose rates that are normally required for biology experiments, the individual events can not be separated by radiation detectors. However, the total energy deposited in a specified time interval can be measured. This total energy has a random variation which depends on the size of the individual events, so the dose mean lineal energy can be calculated from the variance of repeated measurements of the energy deposited in a fixed time. We have developed a specialized charge integration circuit for the measurement of the charge produced in a small ion chamber in typical neutron irradiation experiments. We have also developed 4.3 mm diameter ion chambers with both tissue equivalent and carbon walls for the purpose of measuring dose mean lineal energy due to all radiations and due to all radiations except neutrons, respectively. By adjusting the gas pressure in the ion chamber, it can be made to simulate tissue volumes from a few nanometers to a few millimeters in diameter. The charge is integrated for 0.1 seconds, and the resulting pulse height is recorded by a multi channel analyzer. The system has been used in a variety of photon and neutron radiation fields, and measured values of dose and dose mean lineal energy are consistent with values extrapolated from measurements made by other techniques at much lower dose rates. It is expected that this technique will prove to be much more reliable than extrapolations from measurements made at low dose rates because these low dose rate exposures generally do not accurately reproduce the attenuation and

  16. Monte Carlo Simulations on the water-to-air stopping power ratio for carbon ion dosimetry

    DEFF Research Database (Denmark)

    Henkner, Katrin; Bassler, Niels; Sobolevsky, Nikolai

    2009-01-01

    tables and ICRU reports. The stopping power ratio is calculated via track-length dose calculation with SHIELD-HIT07. In the calculations, the stopping power ratio is reduced to a value of 1.119 in the plateau region as compared to the cited value of 1.13 in IAEA TRS-398. At low energies the stopping...... power ratio increases by up to 6% in the last few tenths of a mm toward the Bragg peak. For a spread out Bragg peak of 13.5  mm width at 130  mm depth, the stopping power ratio increases by about 1% toward the distal end....

  17. Oxygen enhancement ratio as a function of neutron energy with mammalian cells in culture

    International Nuclear Information System (INIS)

    Rini, F.J.; Hall, E.J.; Marino, S.A.

    1979-01-01

    Chinese hamster cells (V79) in culture under oxic and hypoxic conditions were irradiated with several neutron beams spanning a wide energy range to determine the oxygen enhancement ratio (OER). Eight essentially monoenergetic neutron beams, ranging from 0.22 to 13.6 MeV and a 0.11-MeV neutron spectrum, were produced at the Radiological Research Accelerator Facility (RARAF) at Brookhaven National Laboratory. Additional experiments were performed at the Naval Research Laboratory, Washington, DC, where neutrons are produced for radiotherapy by bombarding a beryllium target with 35-MeV deuterons. This beam has a broad energy spectrum with a mean energy of about 15 MeV. A maximum OER of about 1.9 was observed for 13.6-MeV neutrons. The OER values of the monoenergetic neutrons decreased with energy, plateaued at about 1.45 for the energy range from 0.22 to 2.0 MeV and increased slightly to about 1.55 for lower energy spectrum. In the light of microdosimetric data obtained for the neutron beams at RARAF, the OER appears to depend primarily on the intermediate-LET secondaries produced by neutrons in tissue, such as protons, while in contrast high LET-secondaries, such as α-particles and recoil ions, play a minor role. The studies using the NRL neutron beam resulted in a lower OER of about 1.67 as compared to the monoenergetic 13.6-MeV beam. This is a consequence of the fact that more of the dose is deposited by intermediate LET secondaries for the NRL neutron beam

  18. The usefulness of metal markers for CTV-based dose prescription in high-dose-rate interstitial brachytherapy

    International Nuclear Information System (INIS)

    Yoshida, Ken; Mitomo, Masanori; Nose, Takayuki; Koizumi, Masahiko; Nishiyama, Kinji; Yoshida, Mineo

    2002-01-01

    than the maximum normal tissue doses. The doses of 2 markers for (1 patient) for OAR (the urethra) were higher than the maximum normal tissue dose. Seven markers OAR (the mandible) were not visualized because of metal crowns. If the Paris system (reference dose is prescribed to an isodose surface of 85% of the basal dose) had been used, 16 patients had been ''underdosed'' and 4 patients (the rectum+the urethra: 2; the urethra: 1; the large vessel: 1) ''overdosed''. Dose non-uniformity ratio (DNR) and maximum diameter of hyperdose sleeve were 0.31±0.08 and 4-49 mm (median: 7 mm) in CTV-based dose prescription. A statistically significant difference was seen between CTV-based dose prescription and Paris system {0.28±0.08 and 3-99 mm (median: 6 mm)} (p<0.002, 0.0002). Two of 42 patients treated with higher than the tumoricidal dose had local recurrence, while 4 of 7 underdosed patients had local recurrence. A significant difference was found between them (p<0.0001). Metal markers were useful to prescribe the tumoricidal dose to CTV and to regulated the doses for OAR. Local control rate of the patients treated with higher than the tumoricidal dose was significantly better. Miss-implantation of metal markers was a problem that should be resolved. (author)

  19. 15: The accuracy of some dose calculations for three commercial treatment planning systems

    International Nuclear Information System (INIS)

    Wittkaemper, F.W.; Kleffens, H.J. van; Mijnheer, B.J.

    1987-01-01

    The accuracy of some dose calculations with computer planning system for photon beams was investigated by means of a dose intercomparison. Measured dose values in a water phantom were compared with dose values calculated by radiotherapy centres with their computer planning systems. The mean deviation between the calculated and measured dose values is rather small, within 1% for most situations. Only for the wedged beams one planning system showed a systematic deviation of about 2%. The uncertainty in the ratios of calculated to measured dose values was within 2.5% (1 S.D.) for the investigated situations in this study. 8 refs.; 5 figs

  20. Pengaruh Inventory Turnover Ratio, Account Payable to Cost of Goods Sold Ratio, Net Working Capital to Total Asset Ratio, dan Debt Ratio Terhadap Gross Profit Margin

    OpenAIRE

    Fransisca, Maria

    2015-01-01

    The purpose of this study was to determine whether the Inventory Turnover Ratio, Accounts Payable to Cost of Goods Sold Ratio, Net Working Capital to Total Assets Ratio, and Debt Ratio influence simultaneously and partially on the gross profit margin in the consumer goods sector of manufacture companies listed on the Indonesia Stock Exchange . This research is a type of associative causal research with research population are the consumer goods sector of manufacture companies listed on...

  1. Radiation produced biomaterials

    International Nuclear Information System (INIS)

    Rosiak, J.M.

    1998-01-01

    radiation technique. Immobilization of biologically active species in hydrogel matrices, their use as drug delivery systems and enzyme traps as well as modification of material surfaces to improve their biocompatibility and ability to bond antigens and antibodies have been the main subject of their investigations. The rising interest in the field of application of radiation to bioengineering was also recognized by the International Atoimc Energy Agency, which has initiated the international programs relating to those studies. In these lectures some directions of investigations on the formation of hydrogels and their applications for biomedical purposes have been specified. Also, some examples of commercialized products being produced by means of radiation technique have been presented

  2. Peripheral doses of cranial pediatric IMRT performed with attenuator blocks; Doses perifericas de IMRT cranial pediatrica realizada com blocos atenuadores

    Energy Technology Data Exchange (ETDEWEB)

    Soboll, Danyel Scheidegger; Schitz, Ivette; Schelin, Hugo Reuters, E-mail: soboll@utfpr.edu.b, E-mail: iveteschitz@yahoo.com.b, E-mail: schelin@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Silva, Ricardo Goulart da, E-mail: ricardo.goulart@ymail.co [Hospital Angelina Caron, Campina Grande do Sul, PR (Brazil); Viamonte, Alfredo, E-mail: aviamonte@inca.gov.b [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil)

    2011-10-26

    This paper presents values of peripheral doses measured at six vital points of simulator objects which represent the ages of 2, 5 and 10 years old, submitted to a cranial IMRT procedure that applied compensator blocks interposed to 6 MV beams. The found values indicate that there is independence of dose with position of measurements and age of the patient, as the peripheral dose at the points nearest and the 2 year old simulator object where larger. The doses in thyroid reached the range of 1.4 to 2.9% of the dose prescribed in the isocenter, indicating that the peripheral doses for IMRT that employ compensator blocks can be greater than for the IMRT produced with sliding window technique

  3. Isoeffective dose: a concept for biological weighting of absorbed dose in proton and heavier-ion therapies

    CERN Document Server

    Wambersie, A; Menzel, H G; Gahbauer, R; DeLuca, P M; Hendry, J H; Jones, D T L

    2011-01-01

    When reporting radiation therapy procedures, International Commission on Radiation Units and Measurements (ICRU) recommends specifying absorbed dose at/in all clinically relevant points and/or volumes. In addition, treatment conditions should be reported as completely as possible in order to allow full understanding and interpretation of the treatment prescription. However, the clinical outcome does not only depend on absorbed dose but also on a number of other factors such as dose per fraction, overall treatment time and radiation quality radiation biology effectiveness (RBE). Therefore, weighting factors have to be applied when different types of treatments are to be compared or to be combined. This had led to the concept of `isoeffective absorbed dose', introduced by ICRU and International Atomic Energy Agency (IAEA). The isoeffective dose D(IsoE) is the dose of a treatment carried out under reference conditions producing the same clinical effects on the target volume as those of the actual treatment. It i...

  4. Contribution to the problem of liquidity ratios

    Directory of Open Access Journals (Sweden)

    Dvoøáèek Jaroslav

    1997-03-01

    Full Text Available The article is based on the importance of the financial analysis in mining industry. The author pays attention to liquidity ratios given in literature from the standpoint of their number, content, units and recommended quantity value of single ratios. For the application in practice two liquidity ratios are suggested and the methodology of their recommended values determination is given.

  5. Spectrophotometry mole ratio and continuous variation experiments ...

    African Journals Online (AJOL)

    For spectrophotometric determinations of various metal (M) to ligand (L) ratio's in dithizonato metal complexes this reagent provides a versatile alternative for undergraduate chemistry practicals that is cost-effective, yielding repeatable results. The mole-ratio method yield a ratio of 1M : 1L for the silver dithizonate complex ...

  6. Relationships between breath ratios, spirituality and health ...

    African Journals Online (AJOL)

    The aim of this retrospective, quantitative study was to investigate relationships between breath ratios, spirituality perceptions and health perceptions, with special reference to breath ratios that best predict optimal health and spirituality. Significant negative correlations were found between breath ratios and spirituality ...

  7. Ratio of late to early radionuclide uptake: a method for distinguishing osteoporosis from osteomalacia in animal models. [/sup 131/Ba, /sup 85/Sr, /sup 203/Pb, /sup 111/In, rats

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, J.S.; Genant, H.K.; Hattner, R.S.; Hoffer, P.B.

    1978-01-01

    The ratio of late to early uptake of several radionuclides was examined as a method for distinguishing states of abnormal bone metabolism. Nutritional osteoporosis (secondary hyperparathyroidism) and osteomalacia were produced in young rats and compared to a control group. The ratio of early (3 to 6 hrs) to late (4 to 6 days) uptake of barium-131, nitrate, indium-111 EDTMP, and lead-203 were studied, as was that of strontium-85 chloride, a calcium analogue. Ratios of late to early uptake were found to distinguish osteomalacia from osteoporosis in the models when strontium-85 or barium-131 were used. Barium-131 may be a clinically useful alternative to strontium-85 in the evaluation of metabolic bone disease due to its shorter half-life and lower radiation dose.

  8. Monte Carlo dose calculation of microbeam in a lung phantom

    International Nuclear Information System (INIS)

    Company, F.Z.; Mino, C.; Mino, F.

    1998-01-01

    Full text: Recent advances in synchrotron generated X-ray beams with high fluence rate permit investigation of the application of an array of closely spaced, parallel or converging microplanar beams in radiotherapy. The proposed techniques takes advantage of the hypothesised repair mechanism of capillary cells between alternate microbeam zones, which regenerates the lethally irradiated endothelial cells. The lateral and depth doses of 100 keV microplanar beams are investigated for different beam dimensions and spacings in a tissue, lung and tissue/lung/tissue phantom. The EGS4 Monte Carlo code is used to calculate dose profiles at different depth and bundles of beams (up to 20x20cm square cross section). The maximum dose on the beam axis (peak) and the minimum interbeam dose (valley) are compared at different depths, bundles, heights, widths and beam spacings. Relatively high peak to valley ratios are observed in the lung region, suggesting an ideal environment for microbeam radiotherapy. For a single field, the ratio at the tissue/lung interface will set the maximum dose to the target volume. However, in clinical application, several fields would be involved allowing much greater doses to be applied for the elimination of cancer cells. We conclude therefore that multifield microbeam therapy has the potential to achieve useful therapeutic ratios for the treatment of lung cancer

  9. Chlorine Isotope Ratios in M Giants and S Stars

    Science.gov (United States)

    Maas, Zachary; Pilachowski, C. A.

    2018-01-01

    Chlorine is an odd-Z, light element that has been poorly studied in stars. Recently, the first stellar abundance measurements of the isotopologue 35Cl were made and the 35Cl/37Cl ratio was derived in RZ Ari (Maas et al. 2016). Additional abundance measurements are necessary to understand the Galactic chemical evolution and complex nucleosynthesis of Cl. The Cl isotope ratio in particular is important in distinguishing contributions from different nucleosynthesis sites to the surface abundances of stars. For example, current nucloesynthesis models predict that both isotopes of Cl are produced primarily during core collapse supernovae (CCSNe) with the energy and progenitor mass impacting the isotopic ratio of the ejected material. In addition to CCSNe, 37Cl is formed by the s-process both in massive stars and in AGB stars, and 35Cl may be produced from neutrino spallation. Understanding the formation of the Cl isotopes is also important to studies of the interstellar medium (ISM). A range of Cl isotope ratios mainly between 2 - 3.5 have been measured in star forming regions, in the circumstellar envelopes of evolved stars, and in proto-stellar cores using Cl bearing molecules. Additional measurements of the Cl isotope ratio in nearby stars will test nucleosynthesis models and allow comparisons with the range of isotope ratios observed in the ISM.We build on the results of Maas et al. (2016) by measuring the Cl isotope ratio in six M giants and four S stars using R~50,000 resolution spectra from Phoenix on Gemini South. We find no significant difference between the average Cl isotope ratios in the M stars and S stars and our measurements are consistent with the range of values seen in the ISM. We also find the average Cl ratio to be larger than the predicted isotope ratio of 1.8 for the solar neighborhood. Finally, two S stars, GG Pup and WY Pyx, show anomalously strong HCl features with equivalent widths ~3-5 times larger than the HCl features of other stars of

  10. Studies of absorbed dose determinations and spatial dose distributions for high energy proton beams

    International Nuclear Information System (INIS)

    Hiraoka, Takeshi

    1982-01-01

    Absolute dose determinations were made with three types of ionization chamber and a Faraday cup. Methane based tissue equivalent (TE) gas, nitrogen, carbon dioxide, air were used as an ionizing gas with flow rate of 10 ml per minute. Measurements were made at the entrance position of unmodulated beams and for a beam of a spread out Bragg peak at a depth of 17.3 mm in water. For both positions, the mean value of dose determined by the ionization chambers was 0.993 +- 0.014 cGy for which the value of TE gas was taken as unity. The agreement between the doses estimated by the ionization chambers and the Faraday cup was within 5%. Total uncertainty estimated in the ionization chamber and the Faraday cup determinations is 6 and 4%, respectively. Common sources of error in calculating the dose from ionization chamber measurements are depend on the factors of ion recombination, W value, and mass stopping power ratio. These factors were studied by both experimentally and theoretically. The observed values for the factors show a good agreement to the predicted one. Proton beam dosimetry intercomparison between Japan and the United States was held. Good agreement was obtained with standard deviation of 1.6%. The value of the TE calorimeter is close to the mean value of all. In the proton spot scanning system, lateral dose distributions at any depth for one spot beam can be simulated by the Gaussian distribution. From the Gaussian distributions and the central axis depth doses for one spot beam, it is easy to calculate isodose distributions in the desired field by superposition of dose distribution for one spot beam. Calculated and observed isodose curves were agreed within 1 mm at any dose levels. (J.P.N.)

  11. Revision of tissue-maximum ratio and scatter-maximum ratio concepts for cobalt 60 and higher energy x-ray beams

    International Nuclear Information System (INIS)

    Khan, F.M.; Sewchand, W.; Lee, J.; Williamson, J.F.

    1980-01-01

    The concept of tissue-maximum ratios (TMR) as a basis of dose computations has posed problems when applied to the whole range of clinically used megavoltage beams. Another problem is the definition of scatter-maximum ratio (SMR) which assumes a value of zero at the depth of maximum dose. This paper describes new methods of measuring collimator and phantom scatter correction factors. The definitions of TMR and SMR are modified in order to compute phantom scatter at any depth, including depth of maximum dose. The revised concept is basic and general enough that it can be applied to x-ray beams of any energy, fields of any shape and isocentric as well as non-isocentric modes of treatment

  12. Dose point kernels for beta-emitting radioisotopes

    International Nuclear Information System (INIS)

    Prestwich, W.V.; Chan, L.B.; Kwok, C.S.; Wilson, B.

    1986-01-01

    Knowledge of the dose point kernel corresponding to a specific radionuclide is required to calculate the spatial dose distribution produced in a homogeneous medium by a distributed source. Dose point kernels for commonly used radionuclides have been calculated previously using as a basis monoenergetic dose point kernels derived by numerical integration of a model transport equation. The treatment neglects fluctuations in energy deposition, an effect which has been later incorporated in dose point kernels calculated using Monte Carlo methods. This work describes new calculations of dose point kernels using the Monte Carlo results as a basis. An analytic representation of the monoenergetic dose point kernels has been developed. This provides a convenient method both for calculating the dose point kernel associated with a given beta spectrum and for incorporating the effect of internal conversion. An algebraic expression for allowed beta spectra has been accomplished through an extension of the Bethe-Bacher approximation, and tested against the exact expression. Simplified expression for first-forbidden shape factors have also been developed. A comparison of the calculated dose point kernel for 32 P with experimental data indicates good agreement with a significant improvement over the earlier results in this respect. An analytic representation of the dose point kernel associated with the spectrum of a single beta group has been formulated. 9 references, 16 figures, 3 tables

  13. Ultra-low dose naltrexone enhances cannabinoid-induced antinociception.

    Science.gov (United States)

    Paquette, Jay; Olmstead, Mary C; Olmstead, Mary

    2005-12-01

    Both opioids and cannabinoids have inhibitory effects at micromolar doses, which are mediated by activated receptors coupling to Gi/o-proteins. Surprisingly, the analgesic effects of opioids are enhanced by ultra-low doses (nanomolar to picomolar) of the opioid antagonist, naltrexone. As opioid and cannabinoid systems interact, this study investigated whether ultra-low dose naltrexone also influences cannabinoid-induced antinociception. Separate groups of Long-Evans rats were tested for antinociception following an injection of vehicle, a sub-maximal dose of the cannabinoid agonist WIN 55 212-2, naltrexone (an ultra-low or a high dose) or a combination of WIN 55 212-2 and naltrexone doses. Tail-flick latencies were recorded for 3 h, at 10-min intervals for the first hour, and at 15-min intervals thereafter. Ultra-low dose naltrexone elevated WIN 55 212-2-induced tail flick thresholds without extending its duration of action. This enhancement was replicated in animals receiving intraperitoneal or intravenous injections. A high dose of naltrexone had no effect on WIN 55 212-2-induced tail flick latencies, but a high dose of the cannabinoid 1 receptor antagonist SR 141716 blocked the elevated tail-flick thresholds produced by WIN 55 212-2+ultra-low dose naltrexone. These data suggest a mechanism of cannabinoid-opioid interaction whereby activated opioid receptors that couple to Gs-proteins may attenuate cannabinoid-induced antinociception and/or motor functioning.

  14. Brain radiation doses to patients in an interventional neuroradiology laboratory.

    Science.gov (United States)

    Sanchez, R M; Vano, E; Fernández, J M; Moreu, M; Lopez-Ibor, L

    2014-07-01

    In 2011, the International Commission on Radiologic Protection established an absorbed-dose threshold to the brain of 0.5 Gy as likely to produce cerebrovascular disease. In this paper, the authors investigated the brain doses delivered to patients during clinical neuroradiology procedures in a university hospital. The radiation dose delivered to the brain was investigated in 99 diagnostic and therapeutic interventional neuroradiology procedures. Brain doses were calculated in a mathematic model of an adult standard anthropomorphic phantom by using the technical and radiation dose data of an x-ray biplane system submitted to regular quality controls and calibration programs. For cerebral embolizations, brain doses resulted in a maximum value of 1.7 Gy, with an average value of 500 mGy. Median and third quartile resulted in 400 and 856 mGy, respectively. For cerebral angiography, the average dose in the brain was 100 mGy. This work supports the International Commission on Radiologic Protection recommendation on enhancing optimization when doses to the brain could be higher than 0.5 Gy. Radiation doses should be recorded for all patients and kept as low as reasonably achievable. For pediatric patients and young adults, an individual evaluation of brain doses could be appropriate. © 2014 by American Journal of Neuroradiology.

  15. Dose-area product and entrance surface dose in paediatric radiography

    Energy Technology Data Exchange (ETDEWEB)

    Servomaa, A.; Komppa, T.; Parviainen, T.; Heikkilae, M. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland)

    2003-06-01

    Dose-area products (DAP) in paediatric radiography were measured in four university hospitals in Finland. The entrance surface dose (ESD) was calculated from the measured DAP value for each radiographic projection. The purpose was to combine the results with other European studies for development of diagnostic reference levels for paediatric X-ray examinations. The study included 740 paediatric patients, and a total of 1500 single projections were recorded, including 660 projections from extremities. Results were compared with recommended best practices and diagnostic reference levels for ESD. Ratios of DAP to ESD were studied to estimate the levels of DAP corresponding to recommended ESD reference levels. It is desirable for practical purposes that diagnostic reference levels for radiographic projections are also expressed in terms of dose-area product. (orig.)

  16. Transit dose calculation in high dose rate brachytherapy (HDR ...

    African Journals Online (AJOL)

    Transit doses around a high dose rate 192Ir brachytherapy source were calculated using Sievert Integral at positions where the moving source was located exactly between two adjacent dwell positions. The correspond-ing transit dose rates were obtained by using energy absorption coefficients. Discrete step sizes of 0.25 ...

  17. Conversion of dose volume constraints to dose limits

    Energy Technology Data Exchange (ETDEWEB)

    Dai Jianrong [Department of Radiological Science, St Jude Children' s Research Hospital, Memphis, TN 38105 (United States); Zhu Yunping [Department of Radiological Science, St Jude Children' s Research Hospital, Memphis, TN 38105 (United States)

    2003-12-07

    The purpose of this study is to introduce two techniques for converting dosevolume constraints to dose limits for treatment planning optimization, and to evaluate their performance. The first technique, called dose-sorting, is based on the assumption that higher dose limits should be assigned to the constraint points receiving higher doses, and vice versa. The second technique, the hybrid technique, is a hybrid of the dose-sorting technique and the mixed integer linear programming (MILP) technique. Among all constraint points in an organ at risk, the dose limits for the points far from a dosevolume constraint are determined by dose-sorting, while the dose limits for the points close to a dosevolume constraint are determined by MILP. We evaluated the performance of the two new techniques for one treatment geometry by comparing them with the MILP technique. The dose-sorting technique had a high probability of finding the global optimum when no more than three organs at risk have dose-volume constraints. It was much faster than the MILP technique. The hybrid technique always found the global optimum when the MILP percentage (the percentage of constraint points for which the dose limits are determined by the MILP technique) was large enough, but its computation time increased dramatically with the MILP percentage. In conclusion, the dose-sorting technique and the hybrid technique with a low MILP percentage are clinically feasible.

  18. Natural radioactivity, dose assessment and uranium uptake by agricultural crops at Khan Al-Zabeeb, Jordan.

    Science.gov (United States)

    Al-Kharouf, Samer J; Al-Hamarneh, Ibrahim F; Dababneh, Munir

    2008-07-01

    Khan Al-Zabeeb, an irrigated cultivated area lies above a superficial uranium deposits, is regularly used to produce vegetables and fruits consumed by the public. Both soil and plant samples collected from the study area were investigated for their natural radioactivity to determine the uranium uptake by crops and hence to estimate the effective dose equivalent to human consumption. Concentrations of (238)U, (235)U, (232)Th, (226)Ra, (222)Rn, (137)Cs and (40)K in nine soil profiles were measured by gamma-ray spectrometry whereas watermelon and zucchini crops were analyzed for their uranium content by means of alpha spectrometry after radiochemical separation. Correlations between measured radionuclides were made and their activity ratios were determined to evaluate their geochemical behavior in the soil profiles. Calculated soil-plant transfer factors indicate that the green parts (leaves, stems and roots) of the studied crops tend to accumulate uranium about two orders of magnitude higher than the fruits. The maximum dose from ingestion of 1 kg of watermelon pulp was estimated to be 3.1 and 4.7 nSv y(-1) for (238)U and (234)U, respectively. Estimations of the annual effective dose equivalent due to external exposure showed extremely low values. Radium equivalent activity and external hazard index were seen to exceed the permissible limits of 370 Bq kg(-1) and 1, respectively.

  19. Natural radioactivity, dose assessment and uranium uptake by agricultural crops at Khan Al-Zabeeb, Jordan

    Energy Technology Data Exchange (ETDEWEB)

    Al-Kharouf, Samer J. [Royal Scientific Society, Amman 11941 (Jordan); Al-Hamarneh, Ibrahim F. [Prince Abdullah Bin Ghazi Faculty of Science and IT, Al-Balqa Applied University (BAU), Salt 19117 (Jordan)], E-mail: hamarnehibrahim@yahoo.com; Dababneh, Munir [Prince Abdullah Bin Ghazi Faculty of Science and IT, Al-Balqa Applied University (BAU), Salt 19117 (Jordan)

    2008-07-15

    Khan Al-Zabeeb, an irrigated cultivated area lies above a superficial uranium deposits, is regularly used to produce vegetables and fruits consumed by the public. Both soil and plant samples collected from the study area were investigated for their natural radioactivity to determine the uranium uptake by crops and hence to estimate the effective dose equivalent to human consumption. Concentrations of {sup 238}U, {sup 235}U, {sup 232}Th, {sup 226}Ra, {sup 222}Rn, {sup 137}Cs and {sup 40}K in nine soil profiles were measured by gamma-ray spectrometry whereas watermelon and zucchini crops were analyzed for their uranium content by means of alpha spectrometry after radiochemical separation. Correlations between measured radionuclides were made and their activity ratios were determined to evaluate their geochemical behavior in the soil profiles. Calculated soil-plant transfer factors indicate that the green parts (leaves, stems and roots) of the studied crops tend to accumulate uranium about two orders of magnitude higher than the fruits. The maximum dose from ingestion of 1 kg of watermelon pulp was estimated to be 3.1 and 4.7 nSv y{sup -1} for {sup 238}U and {sup 234}U, respectively. Estimations of the annual effective dose equivalent due to external exposure showed extremely low values. Radium equivalent activity and external hazard index were seen to exceed the permissible limits of 370 Bq kg{sup -1} and 1, respectively.

  20. Natural radioactivity, dose assessment and uranium uptake by agricultural crops at Khan Al-Zabeeb, Jordan

    International Nuclear Information System (INIS)

    Al-Kharouf, Samer J.; Al-Hamarneh, Ibrahim F.; Dababneh, Munir

    2008-01-01

    Khan Al-Zabeeb, an irrigated cultivated area lies above a superficial uranium deposits, is regularly used to produce vegetables and fruits consumed by the public. Both soil and plant samples collected from the study area were investigated for their natural radioactivity to determine the uranium uptake by crops and hence to estimate the effective dose equivalent to human consumption. Concentrations of 238 U, 235 U, 232 Th, 226 Ra, 222 Rn, 137 Cs and 40 K in nine soil profiles were measured by gamma-ray spectrometry whereas watermelon and zucchini crops were analyzed for their uranium content by means of alpha spectrometry after radiochemical separation. Correlations between measured radionuclides were made and their activity ratios were determined to evaluate their geochemical behavior in the soil profiles. Calculated soil-plant transfer factors indicate that the green parts (leaves, stems and roots) of the studied crops tend to accumulate uranium about two orders of magnitude higher than the fruits. The maximum dose from ingestion of 1 kg of watermelon pulp was estimated to be 3.1 and 4.7 nSv y -1 for 238 U and 234 U, respectively. Estimations of the annual effective dose equivalent due to external exposure showed extremely low values. Radium equivalent activity and external hazard index were seen to exceed the permissible limits of 370 Bq kg -1 and 1, respectively

  1. Dose dependency of the frequency of micronucleated binucleated clone cells and of division related median clone sizes difference. Pt. 2

    International Nuclear Information System (INIS)

    Hagemann, G,; Kreczik, A.; Treichel, M.

    1996-01-01

    Following irradiation of the progenitor cells the clone growth of CHO cells decreases as a result of cell losses. Lethally acting expressions of micronuclei are produced by heritable lethal mutations. The dependency of the frequency of micronucleated binucleated clone cells and of the median clone sizes difference on the radiation dose was measured and compared to non-irradiated controls. Using the cytokinesis-block-micronucleus-method binucleated cells with micronuclei were counted as ratio of all binucleated cells within a clone size distribution. This ratio (shortened: micronucleus yield) was determined for all clone size distributions, which had been exposed to different irradiation doses and incubation times. The micronucleus yields were compared to the corresponding median clone sizes differences. The micronucleus yield is linearly dependent on the dose and is independent of the incubation time. The same holds true for the division related median clone sizes difference, which as a result is also linearly dependent on the micronucleus yield. Due to the inevitably errors of the cell count of micronucleated binucleated cells, an automatic measurement of the median clone sizes differences is the preferred method for evaluation of cellular radiation sensitivity for heritable lethal mutations. This value should always be determined in addition, if clone survival fractions are used as predictive test because it allows for an estimation of the remission probability of surviving cells. (orig.) [de

  2. Reducing dose calculation time for accurate iterative IMRT planning

    International Nuclear Information System (INIS)

    Siebers, Jeffrey V.; Lauterbach, Marc; Tong, Shidong; Wu Qiuwen; Mohan, Radhe

    2002-01-01

    A time-consuming component of IMRT optimization is the dose computation required in each iteration for the evaluation of the objective function. Accurate superposition/convolution (SC) and Monte Carlo (MC) dose calculations are currently considered too time-consuming for iterative IMRT dose calculation. Thus, fast, but less accurate algorithms such as pencil beam (PB) algorithms are typically used in most current IMRT systems. This paper describes two hybrid methods that utilize the speed of fast PB algorithms yet achieve the accuracy of optimizing based upon SC algorithms via the application of dose correction matrices. In one method, the ratio method, an infrequently computed voxel-by-voxel dose ratio matrix (R=D SC /D PB ) is applied for each beam to the dose distributions calculated with the PB method during the optimization. That is, D PB xR is used for the dose calculation during the optimization. The optimization proceeds until both the IMRT beam intensities and the dose correction ratio matrix converge. In the second method, the correction method, a periodically computed voxel-by-voxel correction matrix for each beam, defined to be the difference between the SC and PB dose computations, is used to correct PB dose distributions. To validate the methods, IMRT treatment plans developed with the hybrid methods are compared with those obtained when the SC algorithm is used for all optimization iterations and with those obtained when PB-based optimization is followed by SC-based optimization. In the 12 patient cases studied, no clinically significant differences exist in the final treatment plans developed with each of the dose computation methodologies. However, the number of time-consuming SC iterations is reduced from 6-32 for pure SC optimization to four or less for the ratio matrix method and five or less for the correction method. Because the PB algorithm is faster at computing dose, this reduces the inverse planning optimization time for our implementation

  3. Dose mapping of the multi-purpose gamma irradiation facility

    International Nuclear Information System (INIS)

    Cabalfin, E.G.; Lanuza, L.G.; Villamater, D.T.

    1989-01-01

    In radiation processing, reliable dosimetry constitutes a very important part of process control and quality assurance. Radiation dosimetry is the only acceptable method to guarantee that the irradiated product has undergone the correct radiation treatment. In preparation therefore, for the routine operation of the newly installed multi-purpose gamma irradiation facility at the Philippine Nuclear Research Institute (PNRI), dose mapping distribution studies were undertaken. Results of dose distribution in air as well as in dummy product are presented. The effects of product bulk density, product geometry and product to source distance on minimum absorbed dose and uniformity ratio have been determined. (Author)

  4. Deferasirox at therapeutic doses is associated with dose-dependent hypercalciuria.

    Science.gov (United States)

    Wong, Phillip; Polkinghorne, Kevan; Kerr, Peter G; Doery, James C G; Gillespie, Matthew T; Larmour, I; Fuller, Peter J; Bowden, Donald K; Milat, Frances

    2016-04-01

    Deferasirox is an oral iron chelator used widely in the treatment of thalassemia major and other transfusion-dependent hemoglobinopathies. Whilst initial long-term studies established the renal safety of deferasirox, there are now increasing reports of hypercalciuria and renal tubular dysfunction. In addition, urolithiasis with rapid loss of bone density in patients with β thalassemia major has been reported. We conducted a cross-sectional cohort study enrolling 152 adult patients comprising of β thalassemia major (81.5%), sickle cell disease (8%), thalassemia intermedia (2%), HbH disease (6.5%) and E/β thalassemia (2%). Cases were matched with normal control subjects on age, gender and serum creatinine. Iron chelator use was documented and urine calcium to creatinine ratios measured. At the time of analysis, 88.8% of patients were receiving deferasirox and 11.2% were on deferoxamine. Hypercalciuria was present in 91.9% of subjects on deferasirox in a positive dose-dependent relationship. This was not seen with subjects receiving deferoxamine. At a mean dose of 30.2±8.8mg/kg/day, deferasirox was associated with an almost 4 fold increase in urine calcium to creatinine ratio (UCa/Cr). Hypercalciuria was present at therapeutic doses of deferasirox in a dose-dependent manner and warrants further investigation and vigilance for osteoporosis, urolithiasis and other markers of renal dysfunction. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. RESERVAS ORGÂNICAS, RELAÇÃO PARTE AÉREA–RAIZ E C–N E ELIMINAÇÃO DO MERISTEMA APICAL NO CAPIM-XARAÉS SOB DOSES DE NITROGÊNIO E POTÁSSIO ORGANIC RESERVES, AEREAL PART:ROOT AND C:N RATIO AND ELIMINATION OF THE APICAL MERISTEM IN XARAÉS – GRASS UNDER NITROGEN AND POTASSIUM DOSIS

    Directory of Open Access Journals (Sweden)

    Amaury Camilo Valinote

    2007-09-01

    Full Text Available

    como a capacidade de recuperação das plantas for-rageiras após desfolha depende, dentre outros fatores, das reservas orgânicas e da área foliar remanescente, objetivou-se com este estudo quantificar os teores de carboidratos totais não-estruturais (cTnE e de n total, nas raízes, base do caule e coroa, determinar a relação parte aérea–raiz e c–n e eliminação do meristema apical no capim-Xaraés (Brachiaria brizantha cv. Xaraés, submetido a doses de nitrogênio e potássio. O experimento foi desenvolvido em casa-de-vegetação, empregando-se um esquema fatorial 4 x 3, perfazendo doze combinações. Utilizaram-se quatro doses de nitrogênio (0, 75, 150 e 225 mg dm-3 e três do-ses de potássio (0, 50 e 100 mg dm-3. Observou-se efeito (P<0,05 das doses de nitrogênio no aumento dos teores de n total e da produção de MS da base do caule e raiz e redução dos teores de cTnE, sendo as raízes o órgão de armazenamento. Houve interação (P<0,05 para as doses de n x K na relação c–n para todos os órgãos, reduzindo com o aumento das doses dos nutrientes e com a elevação nos teores de n total na coroa com o aumento das doses. A relação parte aérea–raiz e eliminação do meristema apical não sofreu efeito (P>0,05 de nenhum nutriente.

    PALAVRAS-CHAVES: Base do caule, Brachiaria brizantha, coroa, n-total, carboidratos totais não-estruturais, raiz.

    The capacity of recovery of plants after takes away the leaves, depends amongst other factors, of the organic reserves and the remaining foliar area. It was objectified with this study, to quantify meaning of non-structural total carbohydrates (Tnc and of total n, in the roots, base of stem and crown, to determine the relation has broken ae-rial/root and c/n and elimination of meristema apical in the Xaraés Grass (Brachiaria brizantha cv. Xaraés, submitted the rates of nitrogen and potassium. The experiment was lead in a greenhouse. The experimental

  6. A convolution-adapted ratio-TAR algorithm for 3D photon beam treatment planning.

    Science.gov (United States)

    Zhu, X R; Low, D A; Harms, W B; Purdy, J A

    1995-08-01

    A convolution-adapted ratio of tissue-air ratios (CARTAR) method of dose calculation has been developed at the Mallinckrodt Institute of Radiology. This photon pencil-beam algorithm has been developed and implemented specifically for three-dimensional treatment planning. In a standard ratio of tissue-air ratios (RTAR) algorithm, doses to points in irregular field geometries are not adequately modeled. This is inconsistent with the advent of conformal therapy, the goal of which is to conform the dose distribution to the target volume while sparing neighboring sensitive normal critical structures. This motivated us to develop an algorithm that can model the beam penumbra near irregular field edges, while retaining much of the speed for the original RTAR algorithm. The dose calculation algorithm uses two-dimensional (2D) convolutions, computed by 2D fast Fourier transform, of pencil-beam kernels with a beam transmission array to calculate 2D off-axis profiles at a series of depths. These profiles are used to replace the product of the transmission function and measured square-field boundary factors used in the standard RTAR calculation. The 2D pencil-beam kernels were derived from measured data for each modality using commonly available dosimetry equipment. The CARTAR algorithm is capable of modeling the penumbra near block edges as well as the loss of primary and scattered beam in partially blocked regions. This paper describes the dose calculation algorithm, implementation, and verification.

  7. Dose-to-man studies

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Dose-to-Man Studies focused on developing computer data handling and computer modules which permit easy, rapid assessment of the dose to southeastern United States populations from routine or accidental releases of radionuclides to atmospheric and stream systems

  8. Patient dose simulation in X-ray CT using a radiation treatment-planning system

    International Nuclear Information System (INIS)

    Nakae, Yasuo; Oda, Masahiko; Minamoto, Takahiro

    2003-01-01

    Medical irradiation dosage has been increasing with the development of new radiological equipment and new techniques like interventional radiology. It is fair to say that patient dose has been increased as a result of the development of multi-slice CT. A number of studies on the irradiation dose of CT have been reported, and the computed tomography dose index (CTDI) is now used as a general means of determining CT dose. However, patient dose distribution in the body varies with the patient's constitution, bowel gas in the body, and conditions of exposure. In this study, patient dose was analyzed from the viewpoint of dose distribution, using a radiation treatment-planning computer. Percent depth dose (PDD) and the off-center ratio (OCR) of the CT beam are needed to calculate dose distribution by the planning computer. Therefore, X-ray CT data were measured with various apparatuses, and beam data were sent to the planning computer. Measurement and simulation doses in the elliptical phantom (Mix-Dp: water equivalent material) were collated, and the CT irradiation dose was determined for patient dose simulation. The rotational radiation treatment technique was used to obtain the patient dose distribution of CT, and patient dose was evaluated through simulation of the dose distribution. CT images of the thorax were sent to the planning computer and simulated. The result was that the patient dose distribution of the thorax was obtained for CT examination. (author)

  9. Application of Performance Ratios in Portfolio Optimization

    Directory of Open Access Journals (Sweden)

    Aleš Kresta

    2015-01-01

    Full Text Available The cornerstone of modern portfolio theory was established by pioneer work of Harry Markowitz. Based on his mean-variance framework, Sharpe formulated his well-known Sharpe ratio aiming to measure the performance of mutual funds. The contemporary development in computer’s computational power allowed to apply more complex performance ratios, which take into account also higher moments of return probability distribution. Although these ratios were proposed to help the investors to improve the results of portfolio optimization, we empirically demonstrated in our paper that this may not necessarily be true. On the historical dataset of DJIA components we empirically showed that both Sharpe ratio and MAD ratio outperformed Rachev ratio. However, for Rachev ratio we assumed only one level of parameters value. Different set-ups of parameters may provide different results and thus further analysis is certainly required.

  10. Dose. Detriment. Limit assessment

    International Nuclear Information System (INIS)

    Breckow, J.

    2015-01-01

    One goal of radiation protection is the limitation of stochastic effects due to radiation exposure. The probability of occurrence of a radiation induced stochastic effect, however, is only one of several other parameters which determine the radiation detriment. Though the ICRP-concept of detriment is a quantitative definition, the kind of detriment weighting includes somewhat subjective elements. In this sense, the detriment-concept of ICRP represents already at the stage of effective dose a kind of assessment. Thus, by comparing radiation protection standards and concepts interconvertible or with those of environment or occupational protection one should be aware of the possibly different principles of detriment assessment.

  11. Dose classification scheme for digital imaging techniques in diagnostic radiology

    International Nuclear Information System (INIS)

    Hojreh, A.

    2002-04-01

    Purpose: image quality in diagnostic radiology is determined in crucial extent by the signal-noise-ratio, which is proportional to the applied x-ray dose. Onward technological developments in the diagnostic radiology are therefore frequently connected with a dose increase, which subjectively is hardly or even not perceptible. The aim of this work was to define reproducible standards for image quality as a function of dose and expected therapeutical consequence in case of computed tomography of the paranasal sinuses and the upper and lower jaw (dental CT), whereby practical-clinical purposes are considered. Materials and methods: the image quality of computed tomography of the paranasal sinuses and dental CT was determined by standard deviation of the CT-numbers (pixel noise) in a region of interest of the phantom of American Association of Physicists in Medicine (AAPM phantom) and additionally in the patients CT images. The diagnostic quality of the examination was classified on the basis of patients CT images in three dose levels (low dose, standard dose and high dose). Results: the pixel noise of CT of the paranasal sinuses with soft tissue reconstruction amounts to 19.3 Hounsfield units (HU) for low dose, 8.8 HU for standard dose, and below 8 HU for high dose. The pixel noise of the dental CT with bone (high resolution) reconstruction amounts to 344 HU for low dose, 221 HU for standard dose, and below 200 HU for high dose. Suitable indications for low dose CT are the scanning of body regions with high contrast differences, like the bony delimitations of air-filled spaces of the facial bones, and radiological follow-up examinations with dedicated questions such as axis determination in dental implantology, as well as the images of objects with small diameter such as in case of children. The standard dose CT can be recommended for all cases, in which precise staging of the illness plays an indispensable role for the diagnosis and therapy planning. With high dose

  12. Iso-effect tables and therapeutic ratios for epidermoid cancer and normal tissue stroma

    International Nuclear Information System (INIS)

    Cohen, L.; Creditor, M.

    1983-01-01

    Available literature on radiation injury to normal tissue stroma and ablation of epidermoid carcinoma was surveyed. Computer programs (RAD3 and RAD1) were then used to derive cell kinetic parameters and generate iso-effect tables for the relevant tissues. The two tables provide a set of limiting doses for tolerance of normal connective tissue (16% risk of injury) and for ablation of epidermoid cancer (16% risk of recurrence) covering a wide range of treatment schedules. Calculating the ratios of normal tissue tolerance to tumor control doses for each treatment scheme provides an array of therapeutic ratios, from which appropriate treatment schemes can be selected

  13. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1991-01-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source terms; environmental transport environmental monitoring data; demographics, agriculture, food habits; environmental pathways and dose estimates.

  14. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1992-02-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demography, food consumption, and agriculture; environmental pathways and dose estimates.

  15. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, S.D.; Finch, S.M. (comps.)

    1992-10-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates):Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates.

  16. Hanford Environmental Dose Reconstruction Project

    Energy Technology Data Exchange (ETDEWEB)

    Finch, S.M.; McMakin, A.H. (comps.)

    1992-01-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates.

  17. Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    Cannon, S.D.; Finch, S.M.

    1992-10-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates):Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates

  18. Rectal dose sparing with a balloon catheter and ultrasound localization in conformal radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Patel, Rakesh R.; Orton, Nigel; Tome, Wolfgang A.; Chappell, Rick; Ritter, Mark A.

    2003-01-01

    , respectively. Averaged over all conditions, inflation of the rectal balloon resulted in a significant reduction in rectal volume receiving ≥65 Gy to a mean ratio of 0.61 (P=0.01) or, in other words, a mean fractional high dose rectal sparing of 39%. There was a slight overall increase to 1.13 in the relative volume of bladder receiving at least 65 Gy; however, this was not significant (P=0.6). Use of an endorectal balloon with a non-image-guided 3D-CRT plan produced about as much rectal dose sparing as a highly conformal, image-guided IMRT approach without a balloon. However, inclusion of a balloon with IMRT produced further rectal sparing still. Conclusion: These results indicate that use of a rectal balloon with a 3D-CRT plan incorporating typical treatment margins will produce significant high dose rectal sparing that is comparable to that achieved by a highly conformal IMRT with ultrasound localization. Further sparing is achieved with the inclusion of a balloon catheter in an IMRT plan. Thus, in addition to a previously reported advantage of prostate immobilization, the use of a rectal displacement balloon during daily treatment results in high dose rectal wall sparing during both modestly and highly conformal radiotherapy. Such sparing could assist in controlling and limiting rectal toxicity during increasingly aggressive dose escalation

  19. PENGARUH PERUBAHAN RETURN ON ASSETS, PERUBAHAN DEBT TO EQUITY RATIO DAN PERUBAHAN CASH RATIO TERHADAP PERUBAHAN DIVIDEND PAYOUT RATIO

    Directory of Open Access Journals (Sweden)

    Yuli Soesetio

    2008-02-01

    Full Text Available Dividend Payout Ratio used to calculate all of revenue that will be accepted by stockholders as cash dividend, usually explained as percentage. This research was conducted to know several factors that affected change of Dividend Payout Ratio and to know the significance level and the correlation between dependent and independent variable. Analysis instrument used was parametric statistic. Based on the result of statistic test,  The Change of Return on Asset (X1, The Change of Debt to Equity Ratio (X2,  were able to explain dependent variable of the change Dividend Payout Ratio, and The Change of CashRatio can’t explain dependent variable of the change Dividend Payout Ratio

  20. Clinical and cardiovascular alterations produced by scorpion envenomation in dogs

    Directory of Open Access Journals (Sweden)

    F. F. Cordeiro

    2006-01-01

    Full Text Available Scorpionism is a common problem that occurs in tropical and subtropical countries and assumes great medical-sanitary importance due to its fatal effect on sensitive individuals, being able to lead children and aged people to death. The envenomation lethal potential is responsible for the serious cardiopulmonary alterations the scorpion toxin produces in its victims. The present research evaluated the effects of Tityus serrulatus venom on dogs, using two distinct doses: a dose that simulates natural envenomation (0.4 mg/total dose, and an experimental dose (0.25 mg/kg. General clinical signs were observed at different moments after envenomation, and specific data related to the cardiopulmonary system were evaluated by systemic arterial pressure measurement, CK-MB enzymatic activity dosage, and radiographic, electrocardiographic and echocardiographic examinations. Results demonstrated that the scorpion venom, in experimental doses, was able to cause acute and reversible cardiac injury in few days, and, in the dose that simulated natural accident, it produced clinical signs of light envenomation, such as local pain, hyperesthesia, sialorrhea, vomiting, diarrhea, sneeze and prostration.

  1. Liquid Medication Errors and Dosing Tools: A Randomized Controlled Experiment.

    Science.gov (United States)

    Yin, H Shonna; Parker, Ruth M; Sanders, Lee M; Dreyer, Benard P; Mendelsohn, Alan L; Bailey, Stacy; Patel, Deesha A; Jimenez, Jessica J; Kim, Kwang-Youn A; Jacobson, Kara; Hedlund, Laurie; Smith, Michelle C J; Maness Harris, Leslie; McFadden, Terri; Wolf, Michael S

    2016-10-01

    Poorly designed labels and packaging are key contributors to medication errors. To identify attributes of labels and dosing tools that could be improved, we examined the extent to which dosing error rates are affected by tool characteristics (ie, type, marking complexity) and discordance between units of measurement on labels and dosing tools; along with differences by health literacy and language. Randomized controlled experiment in 3 urban pediatric clinics. English- or Spanish-speaking parents (n = 2110) of children ≤8 years old were randomly assigned to 1 of 5 study arms and given labels and dosing tools that varied in unit pairings. Each parent measured 9 doses of medication (3 amounts [2.5, 5, and 7.5 mL] and 3 tools [1 cup, 2 syringes (0.2- and 0.5-mL increments)]), in random order. Outcome assessed was dosing error (>20% deviation; large error defined as > 2 times the dose). A total of 84.4% of parents made ≥1 dosing error (21.0% ≥1 large error). More errors were seen with cups than syringes (adjusted odds ratio = 4.6; 95% confidence interval, 4.2-5.1) across health literacy and language groups (P error rates were seen between the 2 syringe types. Use of a teaspoon-only label (with a milliliter and teaspoon tool) was associated with more errors than when milliliter-only labels and tools were used (adjusted odds ratio = 1.2; 95% confidence interval, 1.01-1.4). Recommending oral syringes over cups, particularly for smaller doses, should be part of a comprehensive pediatric labeling and dosing strategy to reduce medication errors. Copyright © 2016 by the American Academy of Pediatrics.

  2. O sevofluorano em psitacídeos (Amazonas aestiva: determinação da dose mínima (d. a. m para produção de anestesia geral Sevoflurane in psitacines (Amazonas aestiva: determination of minimal anesthetic concentration to produce general anesthesia

    Directory of Open Access Journals (Sweden)

    Alexandra Alves Nicolau

    2002-10-01

    Full Text Available Foram utilizados 10 psitacídeos da espécie Amazonas aestiva (papagaio-verdadeiro. Após contenção física, a anestesia foi induzida com o auxílio de uma máscara facial conectada ao sistema de Maplesson D (BARAKA, utilizando sevofluorano a 6V% e fluxo diluente de O2 de 1,5/min de oxigênio. A determinação da Dose Anestésica Mínima (DAM foi estabelecida de maneira similar àquela proposta por LUDDERS et al. (1990. A DAM obtida neste experimento 3,44V%, que eqüivale a concentração alveolar mínima de mamíferos mostrou-se maior nas aves analisadas quando comparada a obtida nos mamíferos. O anestésico mostrou-se bastante seguro para a espécie, não alterando de forma deletéria as variáveis fisiológicas analisadas.Ten adult psittacines (Amazonas aestiva were used. After appropriate immobilization the anesthetic induction was accomplished with facial mask connect to modified circuit of Maggil using 6V% of Sevofluorano with oxygen flow rate at 1.5/. The Minimal Anesthetic Concentration was determined in a manner similar to that proposed by LUDDERS et al. (1990. The MAC obtained was 3.44V%, higher than MAC. proposed to mammals. Sevoflurane can be used safely in avian species once it did not alter significantly all physiological parameters analyzed.

  3. Space radiation absorbed dose distribution in a human phantom

    Science.gov (United States)

    Badhwar, G. D.; Atwell, W.; Badavi, F. F.; Yang, T. C.; Cleghorn, T. F.

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  4. Calculation of cobalt-60 primary and scatter dose in layered heterogeneous phantoms using primary and scatter dose spread arrays

    International Nuclear Information System (INIS)

    Iwasaki, Akira

    1993-01-01

    A method of making 60 Co γ-ray primary and scatter dose spread arrays in water is described. The primary dose spread array is made using forward and backward primary dose spread equations (h 1 and h 2 ), where both equations contain a laterally spread primary dose equation (G), made from measured dose data in a cork phantom. The scatter dose spread array is made using differential scatter-maximum ratio (dSMR) and differential backscatter factor (dBSF) equations (k 1 and k 2 ), where both equations are made to be continuous on the boundary. Primary and scatter dose calculations are performed along the beam axis in layered cork heterogeneous phantoms. It is found, even for 60 Co γ-rays, that when a small tumor in the lung is irradiated with a field that just surrounds the tumor, the beam entrance surface and lateral side of the tumor may obtain no therapeutic dose, because of loss of longitudinal and lateral electronic equilibrium, and when a large tumor in the lung is irradiated with a field just surrounding the tumor, the lateral side of the tumor may obtain no therapeutic dose due to loss of lateral electronic equilibrium. (author)

  5. Dose planning and dose delivery in radiation therapy

    International Nuclear Information System (INIS)

    Knoeoes, T.

    1991-01-01

    A method has been developed for calibration of CT-numbers to volumetric electron density distributions using tissue substitutes of known elemental composition and experimentally determined electron density. This information have been used in a dose calculation method based on photon and electron interaction processes. The method utilizes a convolution integral between the photon fluence matrix and dose distribution kernels. Inhomogeneous media are accounted for using the theorems of Fano and O'Connor for scaling dose distribution kernels in proportion to electron density. For clinical application of a calculated dose plan, a method for prediction of accelerator output have been developed. The methods gives the number of monitor units that has to be given to obtain a certain absorbed dose to a point inside an irregular, inhomogeneous object. The method for verification of dose distributions outlined in this study makes it possible to exclude the treatment related variance contributions, making an objective evaluation of dose calculations with experiments feasible. The methods for electron density determination, dose calculation and prediction of accelerator output discussed in this study will all contribute to an increased accuracy in the mean absorbed dose to the target volume. However, a substantial gain in the accuracy for the spatial absorbed dose distribution will also follow, especially using CT for mapping of electron density together with the dose calculation algorithm. (au)

  6. Comparison of dose length, area, and volume histograms as quantifiers of urethral dose in prostate brachytherapy

    International Nuclear Information System (INIS)

    Butler, Wayne M.; Merrick, Gregory S.; Dorsey, Anthony T.; Hagedorn, Brenda M.

    2000-01-01

    Purpose: To determine the magnitude of the differences between urethral dose-volume, dose-area, and dose-length histograms (DVH, DAH, and DLH, respectively, or DgH generically). Methods and Materials: Six consecutive iodine-125 ( 125 I) patients and 6 consecutive palladium-103 ( 103 Pd) patients implanted via a modified uniform planning approach were evaluated with day 0 computed tomography (CT)-based dosimetry. The urethra was identified by the presence of a urinary catheter and was hand drawn on the CT images with a mean radius of 3.3 ± 0.7 mm. A 0.1-mm calculation matrix was employed for the urethral volume and surface analysis, and urethral dose points were placed at the centroid of the urethra on each 5-mm CT slice. Results: Although individual patient DLHs were step-like, due to the sparseness of the data points, the composite urethral DLH, DAH, and DVHs were qualitatively similar. The DAH curve delivered more radiation than the other two curves at all doses greater than 90% of the prescribed minimum peripheral dose (mPD) to the prostate. In addition, the DVH curve was consistently higher than the DLH curve at most points throughout that range. Differences between the DgH curves were analyzed by integrating the difference curves between 0 and 200% of the mPD. The area-length, area-volume, and volume-length difference curves integrated in the ratio of 3:2:1. The differences were most pronounced near the inflection point of the DgH curves with mean A 125 , V 125 , and L 125 values of 36.6%, 31.4%, and 23.0%, respectively, of the urethra. Quantifiers of urethral hot spots such as D 10 , defined as the minimal dose delivered to the hottest 10% of the urethra, followed the same ranking: area analysis indicated the highest dose and length analysis, the lowest dose. D 10 was 148% and 136% of mPD for area and length evaluations, respectively. Comparing the two isotopes in terms of the amount of urethra receiving a given dose, 103 Pd implants were significantly

  7. Low-dose helical computed tomography (CT) in the perioperative workup of adolescent idiopathic scoliosis

    International Nuclear Information System (INIS)

    Abul-Kasim, Kasim; Overgaard, Angelica; Maly, Pavel; Ohlin, Acke; Gunnarsson, Mikael; Sundgren, Pia C.

    2009-01-01

    The study aims were to estimate the radiation dose in patients examined with low dose spine CT and to compare it with that received by patients undergoing standard CT for trauma of the same region, as well as to evaluate the impact of dose reduction on image quality. Radiation doses in 113 consecutive low dose spine CTs were compared with those in 127 CTs for trauma. The inter- and intraobserver agreement in measurements of pedicular width, and vertebral rotation, measurements of signal-to-noise ratio and assessment of hardware status were the indicators in the evaluation of image quality. The effective dose of the low dose spine CT (0.37 mSv) was 20 times lower than that of a standard CT for trauma (13.09 mSv). This dose reduction conveyed no impact on image quality. This low dose spine CT protocol allows detailed evaluation that is necessary for preoperative planning and postoperative evaluation. (orig.)

  8. Low-dose helical computed tomography (CT) in the perioperative workup of adolescent idiopathic scoliosis

    Energy Technology Data Exchange (ETDEWEB)

    Abul-Kasim, Kasim; Overgaard, Angelica; Maly, Pavel [Malmoe University Hospital, Department of Radiology, Section of Neuroradiology, University of Lund, Malmoe (Sweden); Ohlin, Acke [Malmoe University Hospital, Department of Orthopaedic Surgery, University of Lund, Malmoe (Sweden); Gunnarsson, Mikael [Malmoe University Hospital, Department of Radiation Physics, University of Lund, Malmoe (Sweden); Sundgren, Pia C. [University of Michigan Health Systems, Department of Radiology, Division of Neuroradiology, Ann Arbor (United States)

    2009-03-15

    The study aims were to estimate the radiation dose in patients examined with low dose spine CT and to compare it with that received by patients undergoing standard CT for trauma of the same region, as well as to evaluate the impact of dose reduction on image quality. Radiation doses in 113 consecutive low dose spine CTs were compared with those in 127 CTs for trauma. The inter- and intraobserver agreement in measurements of pedicular width, and vertebral rotation, measurements of signal-to-noise ratio and assessment of hardware status were the indicators in the evaluation of image quality. The effective dose of the low dose spine CT (0.37 mSv) was 20 times lower than that of a standard CT for trauma (13.09 mSv). This dose reduction conveyed no impact on image quality. This low dose spine CT protocol allows detailed evaluation that is necessary for preoperative planning and postoperative evaluation. (orig.)

  9. Dose specification for 192Ir high dose rate brachytherapy in terms of dose-to-water-in-medium and dose-to-medium-in-medium

    International Nuclear Information System (INIS)

    Fonseca, Gabriel Paiva; Yoriyaz, Hélio; Tedgren, Åsa Carlsson; Nilsson, Josef; Persson, Maria; Reniers, Brigitte; Verhaegen, Frank

    2015-01-01

    Dose calculation in high dose rate brachytherapy with 192 Ir is usually based on the TG-43U1 protocol where all media are considered to be water. Several dose calculation algorithms have been developed that are capable of handling heterogeneities with two possibilities to report dose: dose-to-medium-in-medium (D m,m ) and dose-to-water-in-medium (D w,m ). The relation between D m,m and D w,m for 192 Ir is the main goal of this study, in particular the dependence of D w,m on the dose calculation approach using either large cavity theory (LCT) or small cavity theory (SCT). A head and neck case was selected due to the presence of media with a large range of atomic numbers relevant to tissues and mass densities such as air, soft tissues and bone interfaces. This case was simulated using a Monte Carlo (MC) code to score: D m,m, D w,m (LCT), mean photon energy and photon fluence. D w,m (SCT) was derived from MC simulations using the ratio between the unrestricted collisional stopping power of the actual medium and water. Differences between D m,m and D w,m (SCT or LCT) can be negligible (<1%) for some tissues e.g. muscle and significant for other tissues with differences of up to 14% for bone. Using SCT or LCT approaches leads to differences between D w,m (SCT) and D w,m (LCT) up to 29% for bone and 36% for teeth. The mean photon energy distribution ranges from 222 keV up to 356 keV. However, results obtained using mean photon energies are not equivalent to the ones obtained using the full, local photon spectrum. This work concludes that it is essential that brachytherapy studies clearly report the dose quantity. It further shows that while differences between D m,m and D w,m (SCT) mainly depend on tissue type, differences between D m,m and D w,m (LCT) are, in addition, significantly dependent on the local photon energy fluence spectrum which varies with distance to implanted sources. (paper)

  10. Lateral stress ratios for particulate materials

    Energy Technology Data Exchange (ETDEWEB)

    Lohnes, R.A. [Iowa State University, Ames, IA (United States). Dept. of Civil and Construction Engineering

    1993-11-01

    It was originally intended that the lateral stress ratio, used in silo design, be measured for each ensiled, particulate material; however current practice assumes the ratio to be about 0.4 or recommends theoretical equations to calculate the ratio as a function of the material`s effective friction angle. This paper compares lateral stress ratios of materials measured in zero lateral strain, triaxial tests with ratios calculated by a variety of equations. The particulate materials include: agricultural products, coal, sands, and polyethylene pellets. The measured stress ratios range from 0.22 to. 056. It is shown that the RANKINE equation underestimates the ratio and the HARTMANN equation overestimates it: however the JAKY equations compare very favourably with ratios determined in the triaxial tests. In confined compression tests, the lateral stress ratio is constant during loading; but during unloading, varies with degree of over consolidation. The test allows measurement of wall friction and the experimental loading test results compare favourably with WALKER`s theoretical equation that includes wall friction. Lateral stress ratios measured in confined compression vary from 0.17 to 0.45.

  11. ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER

    Energy Technology Data Exchange (ETDEWEB)

    John R. Gallagher

    2001-07-31

    reactor. Batch tests were conducted to examine naphthenic acid biodegradability under several conditions. The conditions used were seed from the anaerobic reactor, wetland sediments under aerobic and anaerobic conditions, and a sterile control. The naphthenic acid was from a commercial source isolated from Gulf Coast petroleum as was dosed at 2 mg/mL. The incubations were for 30 days at 30 C. The results showed that the naphthenic acids were not biodegraded under anaerobic conditions, but were degraded under aerobic conditions. Despite poor performance of the anaerobic reactor, it remains likely that anaerobic treatment of acetate, toluene, and, potentially, other produced-water components is feasible.

  12. ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER; TOPICAL

    International Nuclear Information System (INIS)

    John R. Gallagher

    2001-01-01

    reactor. Batch tests were conducted to examine naphthenic acid biodegradability under several conditions. The conditions used were seed from the anaerobic reactor, wetland sediments under aerobic and anaerobic conditions, and a sterile control. The naphthenic acid was from a commercial source isolated from Gulf Coast petroleum as was dosed at 2 mg/mL. The incubations were for 30 days at 30 C. The results showed that the naphthenic acids were not biodegraded under anaerobic conditions, but were degraded under aerobic conditions. Despite poor performance of the anaerobic reactor, it remains likely that anaerobic treatment of acetate, toluene, and, potentially, other produced-water components is feasible

  13. Effects produced by nuclear radiation in powdery milk

    International Nuclear Information System (INIS)

    Urena N, F.; Reyes G, A.

    1999-01-01

    The objective of this work is to determine the chemical effects produced by the gamma rays and beta particles radiations on the powdery milk. This work treats on the Pre-dose analysis, sampling radiating, electron spin resonance, acidity, proteins, aminoacids, lactose, fatty acids, peroxides, as well as its experimental results. (Author)

  14. Neutron flux and gamma dose measurement in the BNCT irradiation facility at the TRIGA reactor of the University of Pavia

    Science.gov (United States)

    Bortolussi, S.; Protti, N.; Ferrari, M.; Postuma, I.; Fatemi, S.; Prata, M.; Ballarini, F.; Carante, M. P.; Farias, R.; González, S. J.; Marrale, M.; Gallo, S.; Bartolotta, A.; Iacoviello, G.; Nigg, D.; Altieri, S.

    2018-01-01

    University of Pavia is equipped with a TRIGA Mark II research nuclear reactor, operating at a maximum steady state power of 250 kW. It has been used for many years to support Boron Neutron Capture Therapy (BNCT) research. An irradiation facility was constructed inside the thermal column of the reactor to produce a sufficient thermal neutron flux with low epithermal and fast neutron components, and low gamma dose. In this irradiation position, the liver of two patients affected by hepatic metastases from colon carcinoma were irradiated after borated drug administration. The facility is currently used for cell cultures and small animal irradiation. Measurements campaigns have been carried out, aimed at characterizing the neutron spectrum and the gamma dose component. The neutron spectrum has been measured by means of multifoil neutron activation spectrometry and a least squares unfolding algorithm; gamma dose was measured using alanine dosimeters. Results show that in a reference position the thermal neutron flux is (1.20 ± 0.03) ×1010 cm-2 s-1 when the reactor is working at the maximum power of 250 kW, with the epithermal and fast components, respectively, 2 and 3 orders of magnitude lower than the thermal component. The ratio of the gamma dose with respect to the thermal neutron fluence is 1.2 ×10-13 Gy/(n/cm2).

  15. Calibration curve to establish the exposure dose at Co60 gamma radiation

    International Nuclear Information System (INIS)

    Guerrero C, C.; Brena V, M.

    2000-01-01

    The biological dosimetry is an adequate method for the dose determination in cases of overexposure to ionizing radiation or doubt of the dose obtained by physical methods. It is based in the aberrations analysis produced in the chromosomes. The behavior of leisure in chromosomes is of dose-response type and it has been generated curves in distinct laboratories. Next is presented the curve for gamma radiation produced in the National Institute of Nuclear Research (ININ) laboratory. (Author)

  16. Dose rate effects during damage accumulation in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Caturla, M.J.; Diaz de la Rubia, T.

    1997-01-01

    We combine molecular dynamics and Monte Carlo simulations to study damage accumulation and dose rate effects during irradiation of Silicon. We obtain the initial stage of the damage produced by heavy and light ions using classical molecular dynamics simulations. While heavy ions like As or Pt induce amorphization by single ion impact, light ions like B only produce point defects or small clusters of defects. The amorphous pockets generated by heavy ions are stable below room temperature and recrystallize at temperatures below the threshold for recrystallization of a planar amorphous-crystalline interface. The damage accumulation during light ion irradiation is simulated using a Monte Carlo model for defect diffusion. In this approach, we study the damage in the lattice as a function of dose and dose rate. A strong reduction in the total number of defects left in the lattice is observed for lower dose rates.

  17. Influence of low dose ionizing radiation on amplification and antitumor activity of LAK/TIL cells

    International Nuclear Information System (INIS)

    Liu Wei; Hou Dianjun; Qiao Jianwei; Shang Ximei; Li Jieqing

    2000-01-01

    Objective: To study the influence of low dose ionization on amplification and antitumor activity of LAK/TIL cells. Methods: TIL cells isolated from Lewis lung cancer tissues and LAK cells from spleen of tumor-bearing mouse were irradiated with different low doses of X-rays and were cultured after irradiation. Results: Low dose ionizing radiation improved the amplification volume of LAK/TIL cells, decreased the cell death ratio in amplification process, and increased the toxicity of LAK/TIL cells, Conclusions: Low dose ionizing radiation can result in amplification of biologically activated lymphocytes, and decreases the death ratio of the cells in amplification process

  18. New recommendations for dose equivalent

    International Nuclear Information System (INIS)

    Bengtsson, G.

    1985-01-01

    In its report 39, the International Commission on Radiation Units and Measurements (ICRU), has defined four new quantities for the determination of dose equivalents from external sources: the ambient dose equivalent, the directional dose equivalent, the individual dose equivalent, penetrating and the individual dose equivalent, superficial. The rationale behind these concepts and their practical application are discussed. Reference is made to numerical values of these quantities which will be the subject of a coming publication from the International Commission on Radiological Protection, ICRP. (Author)

  19. Therapeutic dose from a pyroelectric electron accelerator.

    Science.gov (United States)

    Fullem, T Z; Fazel, K C; Geuther, J A; Danon, Y

    2009-11-01

    Simple heating of pyroelectric crystals has been used as the basis for compact sources of X rays, electrons, ions and neutrons. We report on the evaluation of the feasibility of using a portable pyroelectric electron accelerator to deliver a therapeutic dose to tissue. Such a device could be mass produced as a handheld, battery-powered instrument. Experiments were conducted with several crystal sizes in which the crystal was heated inside a vacuum chamber and the emitted electrons were allowed to penetrate a thin beryllium window into the surrounding air. A Faraday cup was used to count the number of electrons that exited the window. The energy of these electrons was determined by measuring the energy spectrum of the X rays that resulted from the electron interactions with the Faraday cup. Based on these measurements, the dose that this source could deliver to tissue was calculated using Monte Carlo calculations. It was found that 10(13) electrons with a peak energy of the order of 100 keV were emitted from the beryllium window and could deliver a dose of 1664 Gy to a 2-cm-diameter, 110-microm-deep region of tissue located 1.5 cm from the window with air between the window and the tissue. This dose level is high enough to consider this technology for medical applications in which shallow energy deposition is beneficial.

  20. Recent patents in pressurised metered dose inhalers.

    Science.gov (United States)

    Ehtezazi, Touraj

    2012-04-01

    In this paper recent patents in pressurised metered dose inhalers have been reviewed. The patents are related to novel valves, dose-counters, formulations, add-on devices, reduction of propellant leakage and inkjet technology. Recently patented dose-counters provide mechanisms that are less susceptible to inaccuracy, and are battery-less electronic dose-counters with the help of miniature electromechanical generators. Regarding the formulation aspect, recent patents provide methods for combinational pMDIs and more stable products. Advantages of recently patented valves are being spring-free and less subject to loss of prime. Recent developments in micromachining have allowed patents that incorporate inkjet technology to develop inhalers that are similar to pMDIs, but produce uniform aerosol droplets. Coating canisters with suitable polymers has reduced need for excipients. Recently patented add-on devices reduce aerosol deposition in the spacer by creating turbulence on the walls of the chamber. Blockage of nozzles in actuators is prevented by providing tapered nozzle channels. In conclusion, these patents show better understanding of pMDIs and provide methods to achieve products with much improved reliability, aerosol performance and stability.

  1. Variable Ratio Hydrostatic Transmission Simulator for Optimal Wind Power Drivetrains

    Directory of Open Access Journals (Sweden)

    Jose M. Garcia-Bravo

    2017-01-01

    Full Text Available This work presents a hydromechanical transmission coupled to an electric AC motor and DC generator to simulate a wind power turbine drive train. The goal of this project was to demonstrate and simulate the ability of a hydrostatic variable ratio system to produce constant electric power at varying wind speeds. The experimental results show that the system can maintain a constant voltage when a 40% variation in input speed is produced. An accompanying computer simulation of the system was built and experimentally validated showing a discrete error no larger than 12%. Both the simulation and the experimental results show that the electrical power output can be regulated further if an energy storage device is used to absorb voltage spikes produced by abrupt changes in wind speed or wind direction.

  2. Eccentric crank variable compression ratio mechanism

    Science.gov (United States)

    Lawrence, Keith Edward [Kobe, JP; Moser, William Elliott [Peoria, IL; Roozenboom, Stephan Donald [Washington, IL; Knox, Kevin Jay [Peoria, IL

    2008-05-13

    A variable compression ratio mechanism for an internal combustion engine that has an engine block and a crankshaft is disclosed. The variable compression ratio mechanism has a plurality of eccentric disks configured to support the crankshaft. Each of the plurality of eccentric disks has at least one cylindrical portion annularly surrounded by the engine block. The variable compression ratio mechanism also has at least one actuator configured to rotate the plurality of eccentric disks.

  3. Dose estimative in operators during petroleum wells logging with nuclear wireless probes through computer modelling

    International Nuclear Information System (INIS)

    Souza, Edmilson Monteiro de; Silva, Ademir Xavier da; Lopes, Ricardo T.; Correa, Samanda Cristine Arruda; Rocha, Paula L.F.

    2011-01-01

    This paper evaluates the absorbed dose and the effective dose on operators during the petroleum well logging with nuclear wireless that uses gamma radiation sources. To obtain the data, a typical scenery of a logging procedure will be simulated with MCNPX Monte Carlo code. The simulated logging probe was the Density Gamma Probe - TRISOND produced by Robertson Geolloging. The absorbed dose values were estimated through the anthropomorphic simulator in male voxel MAX. The effective dose values were obtained using the ICRP 103

  4. Peripheral dose from megavolt beams

    International Nuclear Information System (INIS)

    Fraass, B.A.; van de Geijn, J.

    1983-01-01

    The peripheral dose (PD), defined as the dose outside of therapeutic radiation beams, has been investigated for 60 Co, 4-, 6-, and 10-MV x-ray machines. The measurements have been carried out down to dose levels of about 0.1% of the peak dose in the beam, since that dose level may be of clinical importance in some situations. The PD measurements for the various machines are qualitatively similar, which allows the identification of a simple basic data set which can characterize the PD for any particular machine. The PD has been separated into two components: in-phantom scatter dose and transmission (leakage) dose. Knowledge of the two components is important clinically when shielding is considered

  5. Producers give prices a boost

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Uranium producers came alive in August, helping spot prices crack the $8.00 barrier for the first time since March. The upper end of NUKEM's price range actually finished the month at $8.20. Scrambling to fulfill their long-term delivery contracts, producers dominate the market. In the span of three weeks, five producers came out for 2 million lbs U3O8, ultimately buying nearly 1.5 million lbs. One producer accounted for over half this volume. The major factor behind rising prices was that producers required specific origins to meet contract obligations. Buyers willing to accept open origins created the lower end of NUKEM's price range

  6. Therapeutic ratio and fractionation in cancer of the lung

    International Nuclear Information System (INIS)

    Cox, J.D.; Bauer, M.

    1988-01-01

    Bronchopulmonary carcinomas have long been considered among the most frustrating problems in radiation oncology. In spite of the reasonably favorable results reported over 30 years ago with conventional X-irradiation of patients with operable carcinoma of the lung, the patients usually referred for radiation therapy with unresectable tumors permit few opportunities for successful treatment and thus lead to a general nihilism about this disease. The potential damage that can occur from radiation therapy to the normal lung can be life-threatening. Such damage was thought, erroneously, to be increased dramatically with even moderately high doses, e.g.; more than 50 Gy in 5 weeks. Therefore, few attempts were made to deliver the same high doses of radiations that would be considered mandatory for epithelial tumors of other locations such as the upper respiratory and digestive tract or the female genital tract. The therapeutic ratio was altered in an unfavorable direction with the use of small numbers of large fractions. Based on the earliest RTOG studies of carcinoma of the lung, the therapeutic ratio is at an acceptable level with 60 Gy in 30 fractions of 2.0 Gy in 6 weeks. It is encouraging that there is no evidence of an increased rate of morbidity in the hyperfractionation trials of the RTOG. The data are too preliminary with regard to therapeutic effect to know if there will truly be an increase in therapeutic ratio. It was evident that 12-24 months of follow-up are necessary before definitive answers are available

  7. Survival of spermatogonial stem cells in the rat after split dose irradiation during LH-RH analogue treatment

    International Nuclear Information System (INIS)

    Kroonenburgh, M.J.P.G. van; Daal, W.A.J. van; Beck, J.L.; Vemer, H.M.; Rolland, R.

    1987-01-01

    A rat model has been created in which a single injection of an LH-RH analogue depot preparation (Zoladex, ICI 118630) produced a temporary interruption of the pituitary-gonadal axis. This effect applied during irradiation was investigated as a possible mechanism to protect the testis from radiation damage. A local testicular irradiation dose of 6.0 Gy was given either as a single dose or as a fractionated (2 x 3.0 Gy) dose at different time intervals ranging from 8 to 72 h. Stem cell survival was measured 11 weeks after irradiation by means of the repopulation index and the number of haploid cells (spermatids) measured by flow cytometry. Serum gonadotrophins and testosterone concentrations were measured to evaluate hormonal recovery. No significant differences were observed between serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone and the duration of the fractionation interval. Stem cell survival was higher following fractionated irradiation in comparison with the single dose. For the 8 h interval an increase in recovery ratio was found, amounting to a factor of 5 of the single dose value. The fluctuating pattern of the recovery curves indicated changes in radiosensitivity of stem cells. The combination of hormonal inhibition of spermatogenesis and fractionated irradiation led to a decrease in the absolute numbers of stem cells. However, the stem cell recovery curves were identical to those seen without hormonal inhibition. It was concluded that hormonal pretreatment with Zoladex during split dose irradiation had no protective effect on stem cell survival. 37 refs.; 4 figs

  8. Radioactivity monitoring of Irish dairy produce

    International Nuclear Information System (INIS)

    Kelleher, K.

    2010-01-01

    Full text: The RPII has been carrying out monitoring of milk and dairy produce since 1986. Milk samples are routinely analysed for radiocaesium and strontium-90 as part of the RPII's environmental monitoring programme to determine the doses received to the Irish population from milk consumption. The method the RPII utilises for determining the Sr-90 activity in milk is by measuring the Cerenkov radiation produced by its daughter 90 Y isolated from interfering nuclides such as uranium, thorium, radium and their decay products as well as isotopes of caesium, potassium and strontium by extraction with 10% di-(2-ethylhexyl)phosphate (HDEHP) in toluene. The chemical yield of 90 Y is determined by the acidmetric titration of yttrium nitrate carrier with titriplex III. The levels of Sr-90 and dose to the Irish population from milk consumption have been negligible when compared to other radioactive sources in the Irish environment. Other dairy products are analysed for radiocaesium on a routine basis for commercial customers to ensure the levels of radioactivity in the dairy products fall within EC regulations governing the export/import of dairy produce. The export of milk and milk produce from Ireland is a very important industry, 80% of dairy products produced in Ireland are exported and these exports are worth Euro 2.2 billion annually to the Irish economy. The dairy products are analysed by gamma spectroscopy and include full and skim milk powders, butter, casein, cheese, cream, whey and lactose. The levels of radiocaesium in these products are typically below 5 Bk/kg and fall well within the limit of 370 Bq/kg laid down by the European Community in Council Regulation 737/90. Although the levels of these radionuclides are relatively low the RPII recognises the importance of analysing these samples for radioactivity to inform the public, ensure consumer confidence and, more importantly, to maintain a level of expertise in the RPII in these analytical techniques so that

  9. Feed Supplementation with Thermo-Tolerant, Lactic Acid-Producing Bacteria as Probiotics for Swine Husbandry

    International Nuclear Information System (INIS)

    Tongpim, Saowanit; Khammeng, Terdsak; Luanthisong, Pirat; Sakai, Kenji; Piadang, Nattayana

    2006-09-01

    This research work had an objective to employ the thermo tolerant, lactic acid-producing bacteria, Bacillus coagulans strain NF 1 7 as feed additive for swine raising. The bacterial isolate NF 1 7, kept in the culture collection of Khon Kaen University that could tolerate high temperature and produce lactic acid, was employed in this experiment. Cell suspension of isolate NF 1 7 was exposed to gamma irradiation at various doses (1-5 KGy). The isolated survivors were screened on the basis of forming larger colonies and clear zones than the parent strain NF 1 7 when grown on Glucose- Yeast extract-Peptone (GYP) containing CaCO 3 . We obtained 55 effective isolates which the isolate L 5 I2 to 14(5), designated as K 1 4 was chosen for further experiments. Isolate K 1 4 together with the parent strain were characterized using morphological, physiological and biochemical tests. They were all identified as Bacillus coagulans. All isolates had optimal growth pH of 6.5 and grew best at 42.50 o C. The strain K 1 4 could tolerate the temperature as high as 59 o C and was then employed in the fermentation of food waste that collected from the university cafeteria. It was found that food waste could support growth of Bacillus K 1 4 and produce about 107 to 108 CFU/g food waste within 1-3 days. Nutritional value of the fermented food waste in the form of protein was also increased. When mixing this selected bacterium as feed additive in daily pig rations, it was found that Bacillus K 1 4 helped increase feed conversion ratio and reduced the mortality in weaned piglets. Experiments were also performed with the growing pigs. It showed that Bacillus Sp. K 1 4 significantly improved the feed conversion ratio

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  11. Characterization of Soluble Organics in Produced Water

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, D.T.

    2002-01-16

    -selective electrodes and inductively coupled plasma (ICP)-atomic emission spectrometry (AES). The WSO found in produced water samples was primarily polar in nature and distributed between the low and midrange carbon ranges. Typical levels of total extractable material (TEM) was about 20 mg/L; that associated with the aromatic fraction was present at 0.2 mg/L and that in the saturated hydrocarbon fraction was present at less than 0.02 mg/L. Formic, acetic, and propionic acids were also found in the produced water, occurring at a total concentration of 30 mg/L. It was estimated that the presence of 30 mg/L organic acids would artificially overstate TEM content by 2 mg/L. Of the five tested parameters, the factor that most controlled the total WSO in produced water was that of aqueous phase pH. Beyond a value of pH7 significant quantities of C{sub 10}-C{sub 20} range material become markedly soluble as they deprotonate in a basic aqueous phase. Both the absolute and relative volumes of GOM brine and crude additionally affected total WSO. Produced water appeared to reach a saturation level of WSO at a.50% water/oil ratio. Pressure slightly enhanced WSO by increasing the relative quantity of C{sub 6}-C{sub 10} range material. Temperature primarily altered the relative ratio of carbon ranges within the WSO without significantly elevating the total WSO in the GOM brine. Salinity had the least affect on the chemical character or the carbon size of WSO in produced water.

  12. Deposition of 90Sr in bone and the relevant dose

    International Nuclear Information System (INIS)

    Kawamura, Hisao

    1976-01-01

    The deposition of fallout 90 Sr in bone and radiation dose from the nuclide in Japan is reviewed with special reference to (i) the intraskeletal distribution of 90 Sr and reference bone, (ii) bone models for predicting 90 Sr level and (iii) possible problems in applying dose rate factors to Japanese, especially to infants and adolescents. An evidence is presented for the assumption that the ratio of the 90 Sr concentration in a particular bone to that in vertebra will reach the ratio observed for stable strontium under the virtually constant intake of 90 Sr. The importance of surveying 90 Sr levels in different bones is stressed. Observed Ratios (bone/diet) found for Japanese are noticeably lower than those reported for Europeans and Americans. The recently presented model for the retention of alkaline earth elements in man by ICRP will be useful if only adults are concerned. Dose rate factors for 90 Sr in bone should be given as a function of age for the purpose of better estimation of dose commitments. The cumulative absorbed doses to bone tissues calculated with the Palmley-Mays model and with the Spiers model show remarkably higher levels in school children and young adults than the mean level. (auth.)

  13. LUDEP: A Lung Dose Evaluation Program

    International Nuclear Information System (INIS)

    Birchall, A.; Bailey, M.R.; James, A.C.

    1990-06-01

    A Task Group of the ICRP is currently reviewing its dosimetric model for the respiratory tract with the aim of producing a more comprehensive and realistic model which can be used both for dosimetry and bioassay purposes. This in turn requires deposition, clearance, and dosimetry to be treated in a more detailed manner in than in the current model. In order to examine the practical application and radiological implications of the proposed model, a microcomputer program has been developed in a modular form so that changes can be easily included as the model develops. LUDEP (Lung Dose Evaluation Program) is a user-friendly menu-driven program which can be operated on any IBM-compatible PC. It enables the user to calculate (a) doses to each region of the respiratory tract and all other body organs, and (b) excretion rates and retention curves for bioassay purposes. 11 refs., 4 figs., 6 tabs

  14. SU-F-18C-12: On the Relationship of the Weighted Dose to the Surface Dose In Abdominal CT - Patient Size Dependency

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y; Scott, A; Allahverdian, J [Cedars-Sinai Medical Center, Los Angeles, CA (United States)

    2014-06-15

    Purpose: It is possible to measure the patient surface dose non-invasively using radiolucent dosimeters. However, the patient size specific weighted dose remains unknown. We attempted to study the weighted dose to surface dose relationship as the patient size varies in abdominal CT. Methods: Seven abdomen phantoms (CIRS TE series) simulating patients from an infant to a large adult were used. Size specific doses were measured with a 100 mm CT chamber under axial scans using a Siemens Sensation 64 (mCT) and a GE 750 HD. The scanner settings were 120 kVp, 200 mAs with fully opened collimations. Additional kVps (80, 100, 140) were added depending on the phantom sizes. The ratios (r) of the weighted CT dose (Dw) to the surface dose (Ds) were related to the phantom size (L) defined as the diameter resulting the equivalent cross-sectional area. Results: The Dw versus Ds ratio (r) was fitted to a linear relationship: r = 1.083 − 0.007L (R square = 0.995), and r = 1.064 − 0.007L (R square = 0.953), for Siemens Sensation 64 and GE 750 HD, respectively. The relationship appears to be independent of the scanner specifics. Conclusion: The surface dose to the weighted dose ratio decreases linearly as the patient size increases. The result is independent of the scanner specifics. The result can be used to obtain in vivo CT dosimetry in abdominal CT.

  15. Risk of low-doses in radiodiagnosis; Risque des faibles doses en radiodiagnostic. Mythes, reglementation et rationalite

    Energy Technology Data Exchange (ETDEWEB)

    Cordoliani, Y.S.; Sarrazin, J.L.; Le Frian, G.; Soulie, D.; Leveque, C. [Hopital d`Instruction des Armees du Val-de-Grace, 75 - Paris (France)

    1997-12-31

    The effect of low doses of X-rays is inferred from the indubitable effects of high doses in human carcinogenesis, Genetic and teratogenic effects are mainly inferred from animal experimentation because clinical surveys of irradiated pregnant women have failed to demonstrate such consequences in the children, except for mental retardation after Japanese atomic bombing. Since no evidence of carcinogenic effect has been produced by epidemiological studies for doses lower than 500 mSv. the estimation of the risk due to low doses has been extrapolated from the linear relation between dose and cancers at high doses. Such an extrapolation gives a maximal risk which is falsely used as a probability of cancer. The actual risk lies between zero and this maximal number, and many epidemiologic surveys in people receiving doses much higher than the mean level of background irradiation failed to demonstrate higher rate of cancer. The explanation of this fact, which is supported by the most recent biological data, is the efficacy of the DNA repair system at low level of exposure to ionizing radiations. We expose the principles of regulation of radioprotection for workers, and give estimations of the doses delivered to the patients and the personnel by diagnostic investigations, by comparing these doses with those of natural irradiation. Practical aspect for conventional and computed radiology are exposed for patients and workers. (authors)

  16. Eye lens dose correlations with personal dose equivalent and patient exposure in paediatric interventional cardiology performed with a fluoroscopic biplane system.

    Science.gov (United States)

    Alejo, L; Koren, C; Corredoira, E; Sánchez, F; Bayón, J; Serrada, A; Guibelalde, E

    2017-04-01

    To analyse the correlations between the eye lens dose estimates performed with dosimeters placed next to the eyes of paediatric interventional cardiologists working with a biplane system, the personal dose equivalent measured on the thorax and the patient dose. The eye lens dose was estimated in terms of H p (0.07) on a monthly basis, placing optically stimulated luminescence dosimeters (OSLDs) on goggles. The H p (0.07) personal dose equivalent was measured over aprons with whole-body OSLDs. Data on patient dose as recorded by the kerma-area product (P KA ) were collected using an automatic dose management system. The 2 paediatric cardiologists working in the facility were involved in the study, and 222 interventions in a 1-year period were evaluated. The ceiling-suspended screen was often disregarded during interventions. The annual eye lens doses estimated on goggles were 4.13±0.93 and 4.98±1.28mSv. Over the aprons, the doses obtained were 10.83±0.99 and 11.97±1.44mSv. The correlation between the goggles and the apron dose was R 2 =0.89, with a ratio of 0.38. The correlation with the patient dose was R 2 =0.40, with a ratio of 1.79μSvGy -1 cm -2 . The dose per procedure obtained over the aprons was 102±16μSv, and on goggles 40±9μSv. The eye lens dose normalized to P KA was 2.21±0.58μSvGy -1 cm -2 . Measurements of personal dose equivalent over the paediatric cardiologist's apron are useful to estimate eye lens dose levels if no radiation protection devices are typically used. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. Estimation of Fetal Dose during Radiation Therapy of Pregnant Patient

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Chi Hoon; Kim, Chan Yong; Kim, Bo Gyum; Seo, Suk Jin; Yoo, Sook Hyun; Park, Heung Deuk [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2007-03-15

    To evaluate the effectiveness of a simple and practical shielding device to reduce the fetal dose for a pregnant patient undergoing radiation therapy of brain metastasis. The dose to the fetus was evaluated by simulating the treatments using the anthropomorphic phantom. The prescription dose at mid-brain is 300 cGy x 10 fractions with 6 MV photon with 18 x 22 cm{sup 2} field size. The additional shielding devices to reduce the fetal dose are a shielding wall, cerrobend plates and lead (Pb) sheets over acrylic bridge. Various points of measurement with off-field distance were detected by using ion-chamber (30, 40, 50, and 60 cm) with and without the shielding devices and TLD (30, 40, 50, 60, and 70 cm) only with the shielding devices. The doses to the fetus without shielding were 3.20, 3.21, 1.44, 0.90 cGy at the distances of 30, 40, 50, and 60 cm from the treatment field edge. With shielding, the doses were reduced to 0.88, 0.60, 0.35, 0.25 cGy, and the ratio of the shielding effect varied from 70% to 80%. TLD results were 1.8, 1.2, 0.8, 1.2, and 0.8 cGy (70 cm). The total dose to the fetus was expected to be under 1 cGy during the entire treatment. The essential point during radiation therapy of pregnant patient would be minimizing the fetal dose. 10 cGy to 20 cGy is the threshold dose for fetal radiation effects. Our newly developed device reduced the fetal dose far below the safe level. Therefore, our additional shielding devices are useful and effective to reduce the fetal dose.

  18. modified water-cement ratio law for compressive strength of rice

    African Journals Online (AJOL)

    user

    solid agricultural waste (rice husk) and also produce more sustainable cheaper concrete products. To this end, studies on the development of modified water- cement ratio law for concrete incorporating RHA is timely and justifiable. The relationship between the compressive strength and the cement-water ratio is ...

  19. Criteria for Optimum Mixture - Ratio Distribution Using Several Types of Impinging-Stream Injector Elements

    Science.gov (United States)

    Elverum, G. W., Jr.; Morey, T. F.

    1959-01-01

    Empirical correlations are given relating the mixture-ratio distributions produced by various configurations of impinging-stream injectors and the ratios of density, velocity, and orifice cross-sectional area of the two fluids being mixed. Injector-element designs studied are two-on-one, two-on-two, and four-on-one.

  20. FRAN: financial ratio analysis and more (Version 2.0 for Windows)

    Science.gov (United States)

    Bruce G. Hansen; Arnold J., Jr. Palmer

    1999-01-01

    FRAN is a computer-based, stand-alone program designed to generate important financial and operating ratios from tax and wage forms filed with the Internal Revenue Service. FRAN generates standard profitability, financial/leverage, liquidity/solvency, and activity ratios, as well as unique measures of workforce and capital cost and acquisition. Information produced by...

  1. Curious Sex Ratios and Cytoplasmic Genes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 6. Curious Sex Ratios and Cytoplasmic Genes Microbes Can Distort the Sex Ratio of Populations. Stephen J Freeland Laurence D Hurst. General Article Volume 2 Issue 6 June 1997 pp 68-78 ...

  2. The Divine Ratio and Golden Rectangles.

    Science.gov (United States)

    Cooper, Martin

    1982-01-01

    The material examines aspects of Fibonacci and Lucas sequences, the generation of the Divine Ratio, and the nature of this ratio in golden rectangles, triangles, and figures made up of golden triangles. It is noted Lucas sequence is formed like Fibonacci but has one and three as the first elements. (Author/MP)

  3. How to use and interpret hormone ratios.

    Science.gov (United States)

    Sollberger, Silja; Ehlert, Ulrike

    2016-01-01

    Hormone ratios have become increasingly popular throughout the neuroendocrine literature since they offer a straightforward way to simultaneously analyze the effects of two interdependent hormones. However, the analysis of ratios is associated with statistical and interpretational concerns which have not been sufficiently considered in the context of endocrine research. The aim of this article, therefore, is to demonstrate and discuss these issues, and to suggest suitable ways to address them. In a first step, we use exemplary testosterone and cortisol data to illustrate that one major concern of ratios lies in their distribution and inherent asymmetry. As a consequence, results of parametric statistical analyses are affected by the ultimately arbitrary decision of which way around the ratio is computed (i.e., A/B or B/A). We suggest the use of non-parametric methods as well as the log-transformation of hormone ratios as appropriate methods to deal with these statistical problems. However, in a second step, we also discuss the complicated interpretation of ratios, and propose moderation analysis as an alternative and oftentimes more insightful approach to ratio analysis. In conclusion, we suggest that researchers carefully consider which statistical approach is best suited to investigate reciprocal hormone effects. With regard to the hormone ratio method, further research is needed to specify what exactly this index reflects on the biological level and in which cases it is a meaningful variable to analyze. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Tower Water-Vapor Mixing Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Guastad, Krista; Riihimaki, Laura; none,

    2013-04-01

    The purpose of the Tower Water-Vapor Mixing Ratio (TWRMR) value-added product (VAP) is to calculate water-vapor mixing ratio at the 25-meter and 60-meter levels of the meteorological tower at the Southern Great Plains (SGP) Central Facility.

  5. Estimation of polychlorinated biphenyl fugacity ratios.

    Science.gov (United States)

    Van Noort, Paul C M

    2006-11-01

    On the quantitative comparison of solubilities or vapor pressures of homologous series, the variation in the effect of crystal structure on solid properties may substantially influence the outcome of the comparison. Usually, the effect of this variation is eliminated by comparing values of the liquid state. The ratio of solid to liquid properties is called the fugacity ratio. Fugacity ratios are usually calculated from fusion thermodynamic data. For 41 polychlorinated biphenyls (PCBs), fusion enthalpy was found to be correlated with fusion entropy. Highly linear correlations were observed for non-ortho-PCBs, mono-ortho-PCBs, and diortho-PCBs. Fugacity ratios estimated from the fusion enthalpy-entropy linear regression parameters were equal, within 10% on average, to fugacity ratios calculated from fusion enthalpy for ortho chlorinated PCBs with melting points below 380 K and for non-ortho-PCBs. For ortho chlorinated PCBs with melting points above 380 K, fugacity ratios were better estimated from a nonlinear regression of fugacity ratios against the melting point and the system temperature. For all 209 PCB congeners, fugacity ratios at 298 K are listed on the basis of experimental fusion data or estimates from the regressions.

  6. Osmosis and Surface Area to Volume Ratio.

    Science.gov (United States)

    Barrett, D. R. B.

    1984-01-01

    Describes an experiment designed to help students understand the concepts of osmosis and surface area to volume ratio (SA:VOL). The task for students is to compare water uptake in different sizes of potato cubes and relate differences to their SA:VOL ratios. (JN)

  7. Design of a head phantom produced on a 3D rapid prototyping printer and comparison with a RANDO and 3M lucite head phantom in eye dosimetry applications.

    Science.gov (United States)

    Homolka, Peter; Figl, Michael; Wartak, Andreas; Glanzer, Mathias; Dünkelmeyer, Martina; Hojreh, Azadeh; Hummel, Johann

    2017-04-21

    An anthropomorphic head phantom including eye inserts allowing placement of TLDs 3 mm below the cornea has been produced on a 3D printer using a photo-cured acrylic resin to best allow tissue equivalence. Thus H p (3) can be determined in radiological and interventional photon radiation fields. Eye doses and doses to the forehead have been compared to an Alderson RANDO head and a 3M Lucite skull phantom in terms of surface dose per incident air kerma for frontal irradiation since the commercial phantoms do not allow placement of TLDs 3 mm below the corneal surface. A comparison of dose reduction factors (DRFs) of a common lead glasses model has also been performed. Eye dose per incident air kerma were comparable between all three phantoms (printed phantom: 1.40, standard error (SE) 0.04; RANDO: 1.36, SE 0.03; 3M: 1.37, SE 0.03). Doses to the forehead were identical to eye surface doses for the printed phantom and the RANDO head (ratio 1.00 SE 0.04, and 0.99 SE 0.03, respectively). In the 3M Lucite skull phantom dose on the forehead was 15% lower than dose to the eyes attributable to phantom properties. DRF of a sport frame style leaded glasses model with 0.75 mm lead equivalence measured were 6.8 SE 0.5, 9.3 SE 0.4 and 10.5 SE 0.5 for the RANDO head, the printed phantom, and the 3M Lucite head phantom, respectively, for frontal irradiation. A comparison of doses measured in 3 mm depth and on the surface of the eyes in the printed phantom revealed no difference larger than standard errors from TLD dosimetry. 3D printing offers an interesting opportunity for phantom design with increasing potential as printers allowing combinations of tissue substitutes will become available. Variations between phantoms may provide a useful indication of uncertainty budgets when using phantom measurements to estimate individual personnel doses.

  8. On the calibration of photon dosemeters in the equivalent dose units

    International Nuclear Information System (INIS)

    Bregadze, Yu.I.; Isaev, B.M.; Maslyaev, P.F.

    1980-01-01

    General aspects of transition from exposure dose of photo radiation to equivalent one are considered. By determination the equivalent dose is a function of point location in an irradiated object, that is why it is necessary to know equivalent dose distribution in the human body for uniform description of the risk degree. The international electrotechnical comission recommends to measure equivalent doses at 7 and 800 mg/cm 2 depths in a tissue-equivalent ball with 30 cm diameter, calling them skin equivalent dose and depth equivalent dose, respectively, and to compare them with the permissible 500 mZ and 50 mZ a year, respectively. Practical transition to using equivalent dose for evaluation of radiation danger of being in photon radiation field of low energy should include measures on regraduating already produced dose meters, graduating the dose meters under production and developing the system of their metrologic supply [ru

  9. Methotrexate Dosing Regimen for Plaque-type Psoriasis : A Systematic Review of the Use of Test-dose, Start-dose, Dosing Scheme, Dose Adjustments, Maximum Dose and Folic Acid Supplementation

    NARCIS (Netherlands)

    Menting, Stef P; Dekker, Paul M; Limpens, Jacqueline; Hooft, Lotty; Spuls, Phyllis I

    2016-01-01

    There is a range of methotrexate dosing regimens for psoriasis. This review summarizes the evidence for test-dose, start-dose, dosing scheme, dose adjustments, maximum dose and use of folic acid. A literature search for randomized controlled trials and guidelines was performed. Twenty-three

  10. Methotrexate Dosing Regimen for Plaque-type Psoriasis: A Systematic Review of the Use of Test-dose, Start-dose, Dosing Scheme, Dose Adjustments, Maximum Dose and Folic Acid Supplementation

    NARCIS (Netherlands)

    Menting, Stef P.; Dekker, Paul M.; Limpens, Jacqueline; Hooft, Lotty; Spuls, Phyllis I.

    2016-01-01

    There is a range of methotrexate dosing regimens for psoriasis. This review summarizes the evidence for test-dose, start-dose, dosing scheme, dose adjustments, maximum dose and use of folic acid. A literature search for randomized controlled trials and guidelines was performed. Twenty-three

  11. Scavenging ratios based on inflow air concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Davis, W.E.; Dana, M.T.; Lee, R.N.; Slinn, W.G.N.; Thorp, J.M.

    1991-07-01

    Scavenging ratios were calculated from field measurements made during April 1985. Event precipitation samples were collected at the surface, but air chemistry measurements in the air mass feeding the precipitation were made from an aircraft. In contrast, ratios calculated in previous studies have used air concentration and precipitation chemistry data from only surface measurements. Average scavenging ratios were calculated for SO{sub 4}{sup 2{minus}}, NO{sub 3}{sup {minus}}, NH{sub 4}{sup +}, total sulfate, total nitrate, and total ammonium for 5 events; the geometric mean of these scavenging ratios were 8.5 {times} 10{sup 5}, 5.6 {times} 10{sup 6}, 4.3 {times} 10{sup 5}, 3.4 {times} 10{sup 5}, 2.4 {times} 10{sup 6}, and 9.7 {times} 10{sup 4}, respectively. These means are similar to but less variable than previous ratios formed using only surface data.

  12. Equity Theory Ratios as Causal Schemas.

    Science.gov (United States)

    Arvanitis, Alexios; Hantzi, Alexandra

    2016-01-01

    Equity theory approaches justice evaluations based on ratios of exchange inputs to exchange outcomes. Situations are evaluated as just if ratios are equal and unjust if unequal. We suggest that equity ratios serve a more fundamental cognitive function than the evaluation of justice. More particularly, we propose that they serve as causal schemas for exchange outcomes, that is, they assist in determining whether certain outcomes are caused by inputs of other people in the context of an exchange process. Equality or inequality of ratios in this sense points to an exchange process. Indeed, Study 1 shows that different exchange situations, such as disproportional or balanced proportional situations, create perceptions of give-and-take on the basis of equity ratios. Study 2 shows that perceptions of justice are based more on communicatively accepted rules of interaction than equity-based evaluations, thereby offering a distinction between an attribution and an evaluation cognitive process for exchange outcomes.

  13. Equity Theory Ratios as Causal Schemas

    Directory of Open Access Journals (Sweden)

    Alexios Arvanitis

    2016-08-01

    Full Text Available Equity theory approaches justice evaluations based on ratios of exchange inputs to exchange outcomes. Situations are evaluated as just if ratios are equal and unjust if unequal. We suggest that equity ratios serve a more fundamental cognitive function than the evaluation of justice. More particularly, we propose that they serve as causal schemas for exchange outcomes, that is, they assist in determining whether certain outcomes are caused by inputs of other people in the context of an exchange process. Equality or inequality of ratios in this sense points to an exchange process. Indeed, Study 1 shows that different exchange situations, such as disproportional or balanced proportional situations, create perceptions of give-and-take on the basis of equity ratios. Study 2 shows that perceptions of justice are based more on communicatively accepted rules of interaction than equity-based evaluations, thereby offering a distinction between an attribution and an evaluation cognitive process for exchange outcomes.

  14. Duty ratio of cooperative molecular motors.

    Science.gov (United States)

    Dharan, Nadiv; Farago, Oded

    2012-02-01

    Molecular motors are found throughout the cells of the human body and have many different and important roles. These micromachines move along filament tracks and have the ability to convert chemical energy into mechanical work that powers cellular motility. Different types of motors are characterized by different duty ratios, which is the fraction of time that a motor is attached to its filament. In the case of myosin II (a nonprocessive molecular machine with a low duty ratio), cooperativity between several motors is essential to induce motion along its actin filament track. In this work we use statistical mechanical tools to calculate the duty ratio of cooperative molecular motors. The model suggests that the effective duty ratio of nonprocessive motors that work in cooperation is lower than the duty ratio of the individual motors. The origin of this effect is the elastic tension that develops in the filament which is relieved when motors detach from the track. © 2012 American Physical Society

  15. Water entry of cylindrical bodies with various aspect ratios

    Science.gov (United States)

    Kim, Nayoung; Park, Hyungmin

    2017-11-01

    We experimentally investigate the water entry of cylindrical bodies with different aspect ratio (1.0-8.0), focusing on the deformation of free surface and resulting phenomena over and under the surface. The experiment is performed using a high-speed imaging (upto 10000 fps) and PIV. The head and tail of bodies are hemispherical and the nose part is additionally roughened with a sandpaper to see the effect of roughness as well. The release height is also adjusted to change the impact velocity at the free surface (Reynolds number is order of 105). For smooth surface (without cavity formation), a thin liquid film rises up the body after impacting, gathers at the pole and forms a jet over the free surfaces. The jet is created in the form of a thick and thin jet. The thin jet is produced by a water film riding up the surface of an object, and a thick jet is produced by rising water from underwater as the object sinks. However, as the aspect ratio increases, the liquid film does not fully ride up the body and cannot close, so there is an empty space below the free surface. With roughness (with cavity), the liquid film is detached from the body and splash/dome is formed above the free surface. The splash height and its collapsing time decrease with increasing the aspect ratio. Supported by Grants (MPSS-CG-2016-02, NRF-2017R1A4A1015523) of the Korea government.

  16. Effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Masse, R.

    2006-01-01

    Several groups of human have been irradiated by accidental or medical exposure, if no gene defect has been associated to these exposures, some radioinduced cancers interesting several organs are observed among persons exposed over 100 to 200 mSv delivered at high dose rate. Numerous steps are now identified between the initial energy deposit in tissue and the aberrations of cell that lead to tumors but the sequence of events and the specific character of some of them are the subject of controversy. The stake of this controversy is the risk assessment. From the hypothesis called linear relationship without threshold is developed an approach that leads to predict cancers at any tiny dose without real scientific foundation. The nature and the intensity of biological effects depend on the quantity of energy absorbed in tissue and the modality of its distribution in space and time. The probability to reach a target (a gene) associated to the cancerating of tissue is directly proportional to the dose without any other threshold than the quantity of energy necessary to the effect, its probability of effect can be a more complex function and depends on the quality of the damage produced as well as the ability of the cell to repair the damage. These two parameters are influenced by the concentration of initial injuries in the target so by the quality of radiation and by the dose rate. The mechanisms of defence explain the low efficiency of radiation as carcinogen and then the linearity of effects in the area of low doses is certainly the least defensible scientific hypothesis for the prediction of the risks. (N.C.)

  17. Low Dose Ionizing Radiation Modulates Immune Function

    International Nuclear Information System (INIS)

    Nelson, Gregory A.

    2016-01-01

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a 'Th2 polarized' immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in

  18. Low Dose Ionizing Radiation Modulates Immune Function

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Gregory A. [Loma Linda Univ., CA (United States)

    2016-01-12

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a “Th2 polarized” immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in the

  19. The influence of non-radiation induced ESR background signal from paraffin-alanine probes for dosimetry in the radiotherapy dose range

    International Nuclear Information System (INIS)

    Wieser, A.; Lettau, C.; Fill, U.; Regulla, D.F.

    1993-01-01

    The yield of radicals induced by ionizing radiation in the amino acid alanine and its quantification by ESR spectroscopy has proven excellent reproducibility. Those radicals trapped in the crystal lattice are prevented from recombination providing a thermally very stable system. This allows alanine to be applied as a transfer dosemeter. With paraffin-alanine probes ESR dosimetry can be performed with a standard deviation of ± 0.5% in the dose range from 20 Gy up to 100 kGy. At 1 Gy dose level the error increases to ± 6%. This dose level is three orders of magnitude higher than the calculated detection threshold for alanine with modern X-band ESR spectrometers. It was found that the poor standard deviation at the 1 Gy dose level, is not mainly produced by a bad signal-to-noise ratio but by a variable non-radiation induced ESR background signal from the alanine probes within a batch. In the present study the main sources of error for ESR dosimetry in the dose range below 20 Gy were analyzed. The influences of the production process, UV light and humidity upon the ESR background signal from paraffin-alanine probes were investigated. Measurements are shown indicating a second stable structure of the alanine radical at room temperature. (author)

  20. Angular distributions of absorbed dose of Bremsstrahlung and secondary electrons induced by 18-, 28- and 38-MeV electron beams in thick targets.