National Institute for Nuclear Research

Warsaw, Poland

National Institute for Nuclear Research

Warsaw, Poland
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Vassileva J.,International Atomic Energy Agency | Rehani M.,Harvard University | Al-Naemi H.M.,Hamad Medical Corporation | Al Suwaidi J.S.,Dubai Health Authority | And 28 more authors.
Radiation Protection Dosimetry | Year: 2015

The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDIvol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDIvol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDIvol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided. © The Author 2015. Published by Oxford University Press.


Rehani M.M.,International Atomic Energy Agency | Al-Dhuhli H.,Sultan Qaboos University | Al-Naemi H.M.,Hamad Medical Corporation | Al-Suwaidi J.S.,Dubai Hospital | And 35 more authors.
American Journal of Roentgenology | Year: 2012

OBJECTIVE. The purpose of this study was to assess the frequency of pediatric CT in 40 less-resourced countries and to determine the level of appropriateness in CT use. MATERIALS AND METHODS. Data on the increase in the number of CT examinations during 2007 and 2009 and appropriate use of CT examinations were collected, using standard forms, from 146 CT facilities at 126 hospitals. RESULTS. The lowest frequency of pediatric CT examinations in 2009 was in European facilities (4.3%), and frequencies in Asia (12.2%) and Africa (7.8%) were twice as high. Head CT is the most common CT examination in children, amounting to nearly 75% of all pediatric CT examinations. Although regulations in many countries assign radiologists with the main responsibility of deciding whether a radiologic examination should be performed, in fact, radiologists alone were responsible for only 6.3% of situations. Written referral guidelines for imaging were not available in almost one half of the CT facilities. Appropriateness criteria for CT examinations in children did not always follow guidelines set by agencies, in particular, for patients with accidental head trauma, infants with congenital torticollis, children with possible ventriculoperitoneal shunt malfunction, and young children (< 5 years old) with acute sinusitis. In about one third of situations, nonavailability of previous images and records on previously received patient doses have the potential to lead to unnecessary examinations and radiation doses. CONCLUSION. With increasing use of CT in children and a lack of use of appropriateness criteria, there is a strong need to implement guidelines to avoid unnecessary radiation doses to children. © American Roentgen Ray Society.


PubMed | State Office for Radiological and Nuclear Safety, Syrian Atomic Energy Commission, Ministry of Health, Radiologist Ministry of Health and 28 more.
Type: Journal Article | Journal: Radiation protection dosimetry | Year: 2015

The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided.


Mezhevych S.Y.,Institute for Nuclear Research of Ukraine | Rudchik A.T.,Institute for Nuclear Research of Ukraine | Rusek K.,National Institute for Nuclear Research | Rusek K.,University of Warsaw | And 9 more authors.
European Physical Journal A | Year: 2014

Complete angular distributions of the 14C + 11B elastic and inelastic scattering at the energy Elab (11B) = 45 MeV were measured for the ground and excited states of 11B. The data were analyzed within the optical model and the coupled-reaction-channels method. The parameters of the 14C + 11B optical potential and 11B deformation were deduced. The contributions of one- and two-step transfers of nucleons and clusters into the 14C + 11B elastic and inelastic scattering were calculated. The isotopic differences between the 14C + 11B and 12,13C + 11B scatterings are presented and clearly show the importance of the large angle scattering data for understanding the interaction between light heavy ions. © Società Italiana di Fisica/Springer-Verlag 2014.


Rudchik A.T.,Institute for Nuclear Research of Ukraine | Herashchenko O.V.,Institute for Nuclear Research of Ukraine | Kemper K.W.,Florida State University | Rusek K.,National Institute for Nuclear Research | And 15 more authors.
European Physical Journal A | Year: 2014

New angular distribution data for 7Li + 14N elastic and inelastic scattering at the energy Elab(14N) = 80MeV (c.m. 26.7MeV) are presented. The data were analyzed within the optical model and the coupled-reaction-channels method using a channels-coupling scheme that included the 7Li and 14N inelastic scattering channels, spin reorientations of 7Li and 14N as well as most important transfer reactions. The low-energy excited states of 7Li and 14N were assumed to be collective in nature. The 7Li + 14N potential parameters as well as deformation parameters of 7Li and 14N were deduced. The 7Li + 14N potential and the data were compared with those of 6Li + 14N to observe isotopic differences. The enhanced large-angle elastic and inelastic scattering data are shown to have a large contribution from the ground-state reorientation of 7Li. © 2014, SIF, Springer-Verlag Berlin Heidelberg.


Zarazua-Ortega G.,National Institute for Nuclear Research | Poblano-Bata J.,Autonomous University of Mexico State | Tejeda-Vega S.,National Institute for Nuclear Research | Avila-Perez P.,National Institute for Nuclear Research | And 3 more authors.
The Scientific World Journal | Year: 2013

This study is aimed at assessing atmospheric deposition of heavy metals using the epiphytic moss genera Fabronia ciliaris collected from six urban sites in the Metropolitan Zone of the Toluca Valley in Mexico. The concentrations of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, and Pb were determined by total reflection X-ray fluorescence technique. Results show that the average metal concentration decrease in the following order: Fe (8207 mg/Kg) > Ca (7315 mg/Kg) > K (3842 mg/Kg) > Ti (387 mg/Kg) > Mn, Zn (191 mg/Kg) > Sr (71 mg/Kg) > Pb (59 mg/Kg) > Cu, V (32 mg/Kg) > Cr (24 mg/Kg) > Rb (13 mg/Kg) > Ni (10 mg/Kg). Enrichment factors show a high enrichment for Cr, Cu, Zn, and Pb which provides an evidence of anthropogenic impact in the industrial and urban areas, mainly due to the intense vehicular traffic and the fossil fuel combustion. Monitoring techniques in mosses have proved to be a powerful tool for determining the deposition of heavy metals coming from diverse point sources of pollution. © 2013 Graciela Zarazúa-Ortega et al.


Mejia-Cuero R.,National Institute for Nuclear Research | Mejia-Cuero R.,Toluca Institute of Technology | Garcia-Rosales G.,Toluca Institute of Technology | Longoria-Gandara L.C.,National Institute for Nuclear Research | And 4 more authors.
Journal of Chemistry | Year: 2015

This research presents a study of environmental monitoring at different sampling sites from the Metropolitan Area of the Valley of Toluca (MAVT), Mexico, using mosses (Leskea angustata (Tayl.) and Fabronia ciliaris (Brid.)) and soil samples. The epiphytic mosses and soils were sampled in two campaigns within two periods of the year, a rainy and dry-cold season. The selected sampling sites included urban regions (UR), transitional regions (TR), and protected natural areas (PA). The samples were analyzed by the Instrumental Neutron Activation Analysis (INAA) to determine As, Cr, Hg, and Se principally. However, due to the versatility of the analytic technique used, other elements including Cs, Co, Sc, Sb, Rb, Ce, La, Eu, and Yb were also detected. Statistical analysis (As, Cr, Hg, and Se) was carried out with principal components and cluster analysis methods; this revealed that a good correlation exists between metal content in mosses and the degree of pollution in the areas sampled. The obtained results in mosses showed that the concentrations of As, Cr, Co, Cs, Rb, Ce, La, and Yb increased with respect to the concentrations obtained during the first sampling, whereas Se, Sc, Sb and Eu, concentrations were decreased. For As and Hg, the concentrations were similar in both sampling periods. The soil samples present the most significant concentration. © 2015 R. Mejía-Cuero et al.


Hernandez R.,National Institute for Nuclear Research | Romero J.,National Institute for Nuclear Research | Vazquez S.,National Institute for Nuclear Research | Santillan M.,National Institute for Nuclear Research | Scibetta M.,Belgian Nuclear Research Center
Journal of Testing and Evaluation | Year: 2010

The National Institute for Nuclear Research in Mexico participated in the international research project "Master Curve Approach to Monitor the Fracture Toughness of Reactor Pressure Vessel in Nuclear Power Plants" coordinated by the International Atomic Energy Agency (IAEA), where the loading rate effect on the Master Curve reference temperature, T0, was investigated. The experimental program consisted in quasi-static and dynamic fracture toughness testing of precracked Charpy specimens on the IAEA reference reactor pressure vessel steel Japanese reference quality (JRQ) (A533 Grade B Class 1), which was analyzed with the Master Curve methodology. The tests were carried out in displacement control at two temperatures, -70 and -60°C, and at three load rates, dK/dt=0.1, 1, and 10 MPa√m/s. The determined reference temperatures, T0 (0.1 MPa√m/s)=-73.6±6. 4°C, T0 (1 MPa√m/s)=-63.3±5.4°C, and T 0 (10 MPa√m/s)=-50.3±5°C, are similar to those obtained by other laboratories [IAEA Second Meeting on Master Curve to Monitor the Fracture Toughness of RPVs in NPPs, November 2006, Dresden, Germany]. The shift in T0 within the quasi-static loading rate interval (0.1-2 MPa√m/s) recommended by ASTM E1921-05 ["Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transistion Range," Annual Book of ASTM Standards, Vol. 03.01, ASTM International, West Conshohocken, PA.] is 14.4°C and the shift in T 0 between decades of dK/dt on logarithmic scale is 11°C. The empirical relation proposed by Wallin ["Effect of Strain Rate on the Fracture Toughness Reference Temperature T0 for Ferritic Steels," Recent Advances in Fracture, R. K. Mahidhara et al., Eds., The Minerals, Metals and Materials Society, 1997, pp. 171-182] predicts very well the shift in T0 in the quasi-static loading regime (0.1-2 MPa√m/s). This work provides experimental support to limit the quasi-static loading rate interval in ASTM E1921. Copyright © 2010 by ASTM International.

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