Puerto Rico, Argentina
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Santiago M.,National University of Central Buenos Aires | Santiago M.,CONICET | Marcazzo J.,National University of Central Buenos Aires | Marcazzo J.,CONICET | And 4 more authors.
Radiation Measurements | Year: 2011

Borates have shown to be efficient materials to be employed for ionizing radiation detection given their tissue-equivalent characteristics. Usually, the efficiency of these compounds is largely dependent on the preparation methods and conditions. In this work nominally pure and Dy-doped strontium borates have been prepared by sol-gel method. The thermoluminescence and radioluminescence of the resulting borates have been investigated and correlated to their structural characteristics. © 2011 Elsevier Ltd. All rights reserved.


Di Giorgio M.,Autoridad Regulatoria Nuclear ARN | Vallerga M.B.,Autoridad Regulatoria Nuclear ARN | Radl A.,Autoridad Regulatoria Nuclear ARN | Taja M.R.,Autoridad Regulatoria Nuclear ARN | And 16 more authors.
Radiation Protection Dosimetry | Year: 2013

The bottleneck in data acquisition during biological dosimetry based on a dicentric assay is the need to score dicentrics in a large number of lymphocytes. One way to increase the capacity of a given laboratory is to use the ability of skilled operators from other laboratories. This can be done using image analysis systems and distributing images all around the world. Two exercises were conducted to test the efficiency of such an approach involving 10 laboratories. During the first exercise (E1), the participant laboratories analysed the same images derived from cells exposed to 0.5 and 3 Gy; 100 images were sent to all participants for both doses. Whatever the dose, only about half of the cells were complete with well-spread metaphases suitable for analysis. A coefficient of variation (CV) on the standard deviation of ̃15 % was obtained for both doses. The trueness was better for 3 Gy (0.6 %) than for 0.5 Gy (37.8 %). The number of estimated doses classified as satisfactory according to the z-score was 3 at 0.5 Gy and 8 at 3 Gy for 10 dose estimations. In the second exercise, an emergency situation was tested, each laboratory was required to score a different set of 50 images in 2 d extracted from 500 downloaded images derived from cells exposed to 0.5 Gy. Then the remaining 450 images had to be scored within a week. Using 50 different images, the CVon the estimated doses (79.2 %) was not as good as in E1, probably associated to a lower number of cells analysed (50 vs. 100) or from the fact that laboratories analysed a different set of images. The trueness for the dose was better after scoring 500 cells (22.5 %) than after 50 cells (26.8 %). For the 10 dose estimations, the number of doses classified as satisfactory according to the z-score was 9, for both 50 and 500 cells. Overall, the results obtained support the feasibility of networking using electronically transmitted images. However, before its implementation some issues should be elucidated, such as the number and resolution of the images to be sent, and the harmonisation of the scoring criteria. Additionally, a global website able to be used for the different regional networks, like Share Points, will be desirable to facilitate worldwide communication © The Author 2012. Published by Oxford University Press. All rights reserved.


Di Giorgio M.,Autoridad Regulatoria Nuclear ARN | Barquinero J.F.,Autonomous University of Barcelona | Vallerga M.B.,Autoridad Regulatoria Nuclear ARN | Radl A.,Autoridad Regulatoria Nuclear ARN | And 17 more authors.
Radiation Research | Year: 2011

Well-defined protocols and quality management standards are indispensable for biological dosimetry laboratories. Participation in periodic proficiency testing by interlaboratory comparisons is also required. This harmonization is essential if a cooperative network is used to respond to a mass casualty event. Here we present an international intercomparison based on dicentric chromosome analysis for dose assessment performed in the framework of the IAEA Regional Latin American RLA/9/054 Project. The exercise involved 14 laboratories, 8 from Latin America and 6 from Europe. The performance of each laboratory and the reproducibility of the exercise were evaluated using robust methods described in ISO standards. The study was based on the analysis of slides from samples irradiated with 0.75 (DI) and 2.5 Gy (DII). Laboratories were required to score the frequency of dicentrics and convert them to estimated doses, using their own doseâ€"effect curves, after the analysis of 50 or 100 cells (triage mode) and after conventional scoring of 500 cells or 100 dicentrics. In the conntional scoring, at both doses, all reported frequencies were considered as satisfactory, and two reported doses were considered as questionable. The analysis of the data dispersion among the dicentric frequencies and among doses indicated a better reproducibility for estimated doses (15.6% for DI and 8.8% for DII) than for frequencies (24.4% for DI and 11.4% for DII), expressed by the coefficient of variation. In the two triage modes, although robust analysis classified some reported frequencies or doses as unsatisfactory or questionable, all estimated doses were in agreement with the accepted error of ±±0.5 Gy. However, at the DI dose and for 50 scored cells, 5 out of the 14 reported confidence intervals that included zero dose and could be interpreted as false negatives. This improved with 100 cells, where only one confidence interval included zero dose. At the DII dose, all estimations fell within ±±0.5 Gy of the reference dose interval. The results obtained in this triage exercise indicated that it is better to report doses than frequencies. Overall, in both triage and conventional scoring modes, the laboratory performances were satisfactory for mutual cooperation purposes. These data reinforce the view that collaborative networking in the case of a mass casualty event can be successful. © 2011 by Radiation Research Society.


PubMed | Brazilian Radiological Protection and Dosimetry Institute (IRD), Comision Chilena de Energia Nuclear CHEN, Instituto Nacional de Investigaciones Nucleares, Institute Investigaciones Biologicas Clemente Estable and 2 more.
Type: Journal Article | Journal: Radiation protection dosimetry | Year: 2016

Biological Dosimetry is a necessary support for national radiation protection programmes and emergency response schemes. The Latin American Biological Dosimetry Network (LBDNet) was formally founded in 2007 to provide early biological dosimetry assistance in case of radiation emergencies in the Latin American Region. Here are presented the main topics considered in the foundational document of the network, which comprise: mission, partners, concept of operation, including the mechanism to request support for biological dosimetry assistance in the region, and the network capabilities. The process for network activation and the role of the coordinating laboratory during biological dosimetry emergency response is also presented. This information is preceded by historical remarks on biological dosimetry cooperation in Latin America. A summary of the main experimental and practical results already obtained by the LBDNet is also included.


Molina P.,National University of Central Buenos Aires | Molina P.,CONICET | Santiago M.,National University of Central Buenos Aires | Santiago M.,CONICET | And 7 more authors.
Applied Radiation and Isotopes | Year: 2012

Fiberoptic dosimetry (FOD) technique has become an attractive method for real-time dosimetry. Al2O3:Cis one of the most used radioluminescence materials for FOD due to its high efficiency but it presents the drawback of emitting in the spectral region, where spurious luminescence is also important. Optical filtering is the simplest technique to remove spurious luminescence, but is useful when red-emitting scintillators are employed. In this work, the feasibility of using red-emitting Eu-doped phosphors as FOD scintillators has been investigated. © 2012 Elsevier Ltd.


Caselli E.,National University of Central Buenos Aires | Marcazzo J.,National University of Central Buenos Aires | Marcazzo J.,CONICET | Furetta C.,Touro College | And 4 more authors.
Radiation Measurements | Year: 2011

The models employed so far for deconvolving thermoluminescent glow curves are either derived by neglecting the interaction among traps and resorting to the quasi-equilibrium approximation, or are simply phenomenological. Several published articles have shown that the approximations are difficult to justify. Further it has never been shown that they are rigorously applicable to any known system. As to the phenomenological model it is no physically meaningful. An algorithm is reported which allows analyses of glow curves without the aforementioned approximations. © 2011 Elsevier Ltd. All rights reserved.


Molina P.,CONICET | Ortega F.,CONICET | Marcazzo J.,CONICET | Santiago M.,CONICET | And 3 more authors.
Radiation Measurements | Year: 2015

The kinetic parameters of dosimetric peaks of CaF2:Tm (TLD-300) were found by employing a kinetics model derived from differential equations describing the carriers traffic but without resorting to the quasi-equilibrium approximation. Since both shape and position of glow peaks were observed not to change with dose, retrapping rates have been assumed negligible compared to rates of thermal release of electrons. The reported results show that the quasi-equilibrium approximation does not hold, an approximation used for derivation of first order kinetics, which is the kinetics employed so far for analyzing glow curves of the TLD-300. © 2015 Published by Elsevier Ltd.


Molina P.,National University of Central Buenos Aires | Molina P.,CONICET | Santiago M.,National University of Central Buenos Aires | Santiago M.,CONICET | And 5 more authors.
Radiation Measurements | Year: 2011

The radioluminescence (RL) properties of K 2YF 5 crystals doped with Ce 3+, Tb 3+ and Dy 3+ under ionizing irradiation excitation have been studied for the first time. The main objective of this work has been to assess the feasibility of using these crystals as detectors for fiberoptic radioluminescent dosimetry. In particular, it has been found that the RL intensity from both K 2YF 5:Tb (10%) and K 2TbF 5 is comparable to that from a commercial Al 2O 3:C crystal. Longer wavelength emission from these fluorides makes simple optical filtering technique possible to use in order to avoid the stem effect. Afterglow decay times for these fluorides have been found to be similar to that for Al 2O 3:C and, in particular, K 2TbF 5 does not show longer afterglow decay time compared to Al 2O 3:C. © 2011 Elsevier Ltd. All rights reserved.


Gonzalez A.J.,Autoridad Regulatoria Nuclear ARN
Science and Technology of Nuclear Installations | Year: 2011

The ethical bases of Argentina's radiation safety approach are reviewed. The applied principles are those recommended and established internationally, namely: the principle of justification of decisions that alters the radiation exposure situation; the principle of optimization of protection and safety; the principle of individual protection for restricting possible inequitable outcomes of optimized safety; and the implicit principle of intergenerational prudence for protection future generations and the habitat. The principles are compared vis - vis the prevalent ethical doctrines: justification vis - vis teleology; optimization vis - vis utilitarianism; individual protection vis - vis deontology; and, intergenerational prudence vis - vis aretaicism (or virtuosity). The application of the principles and their ethics in Argentina is analysed. These principles are applied to ALL exposure to radiation harm; namely, to exposures to actual doses and to exposures to actual risk and potential doses, including those related to the safety of nuclear installations, and they are harmonized and applied in conjunction. It is concluded that building a bridge among all available ethical doctrines and applying it to radiation safety against actual doses and actual risk and potential doses is at the roots of the successful nuclear regulatory experience in Argentina. © 2011 Abel J. Gonzlez.


PubMed | Autoridad Regulatoria Nuclear ARN
Type: Comparative Study | Journal: Radiation research | Year: 2011

Well-defined protocols and quality management standards are indispensable for biological dosimetry laboratories. Participation in periodic proficiency testing by interlaboratory comparisons is also required. This harmonization is essential if a cooperative network is used to respond to a mass casualty event. Here we present an international intercomparison based on dicentric chromosome analysis for dose assessment performed in the framework of the IAEA Regional Latin American RLA/9/054 Project. The exercise involved 14 laboratories, 8 from Latin America and 6 from Europe. The performance of each laboratory and the reproducibility of the exercise were evaluated using robust methods described in ISO standards. The study was based on the analysis of slides from samples irradiated with 0.75 (DI) and 2.5 Gy (DII). Laboratories were required to score the frequency of dicentrics and convert them to estimated doses, using their own dose-effect curves, after the analysis of 50 or 100 cells (triage mode) and after conventional scoring of 500 cells or 100 dicentrics. In the conntional scoring, at both doses, all reported frequencies were considered as satisfactory, and two reported doses were considered as questionable. The analysis of the data dispersion among the dicentric frequencies and among doses indicated a better reproducibility for estimated doses (15.6% for DI and 8.8% for DII) than for frequencies (24.4% for DI and 11.4% for DII), expressed by the coefficient of variation. In the two triage modes, although robust analysis classified some reported frequencies or doses as unsatisfactory or questionable, all estimated doses were in agreement with the accepted error of 0.5 Gy. However, at the DI dose and for 50 scored cells, 5 out of the 14 reported confidence intervals that included zero dose and could be interpreted as false negatives. This improved with 100 cells, where only one confidence interval included zero dose. At the DII dose, all estimations fell within 0.5 Gy of the reference dose interval. The results obtained in this triage exercise indicated that it is better to report doses than frequencies. Overall, in both triage and conventional scoring modes, the laboratory performances were satisfactory for mutual cooperation purposes. These data reinforce the view that collaborative networking in the case of a mass casualty event can be successful.

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