SADMFR Guidelines for the Use of Cone-Beam Computed Tomography/Digital Volume Tomography

In 2011, the first consensus conference on guidelines for the use of cone-beam computed tomography (CBCT) was convened by the Swiss Society of Dentomaxillofacial Radiology (SGDMFR). This conference covered topics of oral and maxillofacial surgery, temporomandibular joint dysfunctions and disorders, and orthodontics. In 2014, a second consensus conference was convened on guidelines for the use of CBCT in endodontics, periodontology, reconstructive dentistry and pediatric dentistry. The guidelines are intended for all dentists in order to facilitate the decision as to when the use of CBCT is justified. As a rule, the use of CBCT is considered restrictive, since radiation protection reasons do not allow its routine use. CBCT should therefore be reserved for complex cases where its application can be expected to provide further information that is relevant to the choice of therapy. In periodontology, sufficient information is usually available from clinical examination and periapical radiographs; in endodontics alternative methods can often be used instead of CBCT; and for implant patients undergoing reconstructive dentistry, CT is of interest for the workflow from implant planning to the superstructure. For pediatric dentistry no application of CBCT is seen for caries diagnosis.

Las radiaciones ionizantes en la educación médica de grado de la Universidad Nacional de Cuyo

Las irradiaciones médicas constituyen la contribución más importante a la exposición humana a radiaciones ionizantes de origen artificial. Las estadísticas mundiales indican una tendencia creciente en el número anual de estas prácticas en función del desarrollo de nuevas técnicas de diagnóstico por imágenes, de la aplicación de nuevos fármacos marcados con diversos isótopos y de avances en los tratamientos antineoplásicos. Debido a esta amplia difusión, la Protección Radiológica (PR) se ha convertido en un tema relevante para las sociedades científicas y los organismos reguladores. En este sentido, la mayor parte de los países europeos ha implementado planes de acción para la protección radiológica del paciente. Un ejemplo de ello lo constituye la guía PR/116 elaborada por la Comisión Europea en el año 2000, que recomienda la implementación de un curso en PR en las escuelas de Medicina y Odontología. En consecuencia, el propósito general de esta investigación fue describir y analizar críticamente la situación actual de la enseñanza de contenidos referidos al uso de las radiaciones ionizantes en la carrera de Medicina de la Facultad de Ciencias Médicas de la Universidad Nacional de Cuyo. Los principales resultados muestran que no existe una obligación curricular que presente entre sus contenidos mínimos la enseñanza de la PR, como tampoco de conocimientos básicos de Física de la radiación. Además, tanto la PR como los temas ambientales relativos al uso de radiaciones ionizantes en Medicina no se desarrollan según lo recomendado por Organismos Internacionales especializados. Teniendo en cuenta que muchos métodos de diagnóstico por imágenes utilizan radiaciones ionizantes, se sugiere la inclusión de esta temática en el plan de estudio de la carrera de Medicina. El objetivo es incorporar la cultura de la radioprotección en la formación del futuro profesional y, en consecuencia, reducir la ejecución de prácticas injustificadas que atentan contra la salud individual y ambiental.

Study of the radioactivity induced in air by a 15-MeV proton beam.

Radioactivity induced by a 15-MeV proton beam extracted into air was studied at the beam transport line of the 18-MeV cyclotron at the Bern University Hospital (Inselspital). The produced radioactivity was calculated and measured by means of proportional counters located at the main exhaust of the laboratory. These devices were designed for precise assessment of air contamination for radiation protection purposes. The main produced isotopes were 11C, 13N and 14O. Both measurements and calculations correspond to two different irradiation conditions. In the former, protons were allowed to travel for their full range in air. In the latter, they were stopped at the distance of 1.5 m by a beam dump. Radioactivity was measured continuously in the exhausted air starting from 2 min after the end of irradiation. For this reason, the short-lived 14O isotope gave a negligible contribution to the measured activity. Good agreement was found between the measurements and the calculations within the estimated uncertainties. Currents in the range of 120–370 nA were extracted in air for 10–30 s producing activities of 9–22 MBq of 11C and 13N. The total activities for 11C and 13N per beam current and irradiation time for the former and the latter irradiation conditions were measured to be (3.60 ± 0.48) × 10−3 MBq (nA s)−1 and (2.89 ± 0.37) × 10−3 MBq (nA s)−1, respectively.

Neutron spectrometry using artificial neural networks for a bonner sphere spectrometer with 3He detector

Neutron spectra unfolding and dose equivalent calculation are complicated tasks in radiation protection, are highly dependent of the neutron energy, and a precise knowledge on neutron spectrometry is essential for all dosimetry-related studies as well as many nuclear physics experiments. In previous works have been reported neutron spectrometry and dosimetry results, by using the ANN technology as alternative solution, starting from the count rates of a Bonner spheres system with a LiI(Eu) thermal neutrons detector, 7 polyethylene spheres and the UTA4 response matrix with 31 energy bins. In this work, an ANN was designed and optimized by using the RDANN methodology for the Bonner spheres system used at CIEMAT Spain, which is composed of a He neutron detector, 12 moderator spheres and a response matrix for 72 energy bins. For the ANN design process a neutrons spectra catalogue compiled by the IAEA was used. From this compilation, the neutrons spectra were converted from lethargy to energy spectra. Then, the resulting energy ?uence spectra were re-binned by using the MCNP code to the corresponding energy bins of the He response matrix before mentioned. With the response matrix and the re-binned spectra the counts rate of the Bonner spheres system were calculated and the resulting re-binned neutrons spectra and calculated counts rate were used as the ANN training data set.

An approach to stakeholders involvement in the preparedness for nuclear and radiological emergency response & recovery in Spain

The elaboration of a generic decision-making strategy to address the evolution of an emergency situation, from the stages of response to recovery, and including a planning stage, can facilitate timely, effective and consistent decision making by the response organisations at every level within the emergency management structure and between countries, helping to ensure optimal protection of health, environment, and society. The degree of involvement of stakeholders in this process is a key strategic element for strengthening the local preparedness and response and can help a successful countermeasures strategy. A significant progress was made with the multi-national European project EURANOS (2004-2009) which brought together best practice, knowledge and technology to enhance the preparedness for Europe's response to any radiation emergency and long term contamination. The subsequent establishment of a European Technology Platform and the recent launch of the research project NERIS-TP ("Towards a self sustaining European Technology Platform (NERIS-TP) on Preparedness for Nuclear and Radiological Emergency Response and Recovery") are aimed to continue with the remaining tasks for gaining appropriate levels of emergency preparedness at local level in most European countries. One of the objectives of the NERIS-TP project is: Strengthen the preparedness at the local/national level by setting up dedicated fora and developing new tools or adapting the tools developed within the EURANOS projects (such as the governance framework for preparedness, the handbooks on countermeasures, the RODOS system, and the MOIRA DSS for long term contamination in catchments) to meet the needs of local communities. CIEMAT and UPM in close interaction with the Nuclear Safety Council will explore, within this project, the use and application in Spain of such technical tools, including other national tools and information and communication strategies to foster cooperation between local, national and international stakeholders. The aim is identify and involve relevant stakeholders in emergency preparedness to improve the development and implementation of appropriate protection strategies as part of the consequence management and the transition to recovery. In this paper, an overview of the "state of the art" on this area in Spain and the methodology and work Plan proposed by the Spanish group within the project NERIS to grow the stakeholder involvement in the preparedness to emergency response and recovery is presented.

Characterization of an 241AmBe neutron irradiation facility by different spectrometric techniques

An automated panoramic irradiator with a 3 Ci 241Am-Be neutron source is installed in a bunker-type large room at the Universidad Politécnica de Madrid (UPM). It was recently modified and a neutron spectrometry campaign was organized to characterize the neutron fields in different measurement points along the irradiation bench. Four research groups working with different Bonner Sphere Spectrometers (BSS) and using different spectral unfolding codes took part to this exercise. INFN-LNF used a BSS formed by 9 spheres plus bare detector, with cylindrical, almost point like, 6LiI(Eu) scintillator (4 mm x 4 mm, from Ludlum); UAZ-UPM employed a similar system but with only 6 spheres plus bare detector; UAB worked with a 3He filled proportional counter at 8kPa filling pressure, cylindrical 9 mm x 10 mm (05NH1 from Eurisys) with 11 spheres configuration; and CIEMAT used 12 spheres with an spherical 3He SP9 counter (Centronic Ltd., UK) with very high sensitivity due to the large diameter (3.2 cm) and the filling pressure of the order of 228 kPa. Each group applied a different spectral unfolding method: INFN and UAB worked with FRUIT ver. 3.0 with their own response matrixes; UAZ-UPM used the BUNKIUT unfolding code with the response matrix UTA4 and CIEMAT employed the GRAVEL-MAXED-IQU package with their own response matrix. The paper shows the main results obtained in terms of neutron spectra at fixed distances from the source as well as total neutron fluence rate and ambient dose equivalent rate H*(10) determined from the spectra. The latter are compared with the readings of a common active survey-meter (LB 6411). The small differences in the results of the various groups are discussed.

MOIRA-PLUS use in decision making on the long-term management of contaminated freshwater bodies and catchments

In the mid-long-term after a nuclear accident, the contamination of drinking water sources, fish and other aquatic foodstuffs, irrigation supplies and people?s exposure during recreational activities may create considerable public concern, even though dose assessment may in certain situations indicate lesser importance than for other sources, as clearly experienced in the aftermath of past accidents. In such circumstances there are a number of available countermeasure options, ranging from specific chemical treatment of lakes to bans on fish ingestion or on the use of water for crop irrigation. The potential actions can be broadly grouped into four main categories, chemical, biological, physical and social. In some cases a combination of actions may be the optimal strategy and a decision support system (DSS) like MOIRA-PLUS can be of great help to optimise a decision. A further option is of course not to take any remedial actions, although this may also have significant socio-economic repercussions which should be adequately evaluated. MOIRA-PLUS is designed to allow for a reliable assessment of the long-term evolution of the radiological situation and of feasible alternative rehabilitation strategies, including an objective evaluation of their social, economic and ecological impacts in a rational and comprehensive manner. MOIRA-PLUS also features a decision analysis methodology, making use of multi-attribute analysis, which can take into account the preferences and needs of different types of stakeholders. The main functions and elements of the system are described summarily. Also the conclusions from end-user?s experiences with the system are discussed, including exercises involving the organizations responsible for emergency management and the affected services, as well as different local and regional stakeholders. MOIRAPLUS has proven to be a mature system, user friendly and relatively easy to set up. It can help to better decisionmaking by enabling a realistic evaluation of the complete impacts of possible recovery strategies. Also, the interaction with stakeholders has allowed identifying improvements of the system that have been recently implemented.

Estudio experimental sobre la efectividad y la viabilidad de distintas soluciones constructivas para reducir la concentración de gas radón en edificaciones

El trabajo de investigación desarrollado que ha dado lugar a la realización de esta Tesis, aborda la protección de los edificios frente a la entrada de gas radón y su acumulación en los espacios habitados. Dicho gas (isótopo del radón Rn-222) es un elemento radiactivo que se genera, principalmente, en terrenos con altos contenidos de radio (terrenos graníticos por ejemplo). Su alto grado de movilidad permite que penetre en los edificios a través de los materiales de cerramiento del mismo (porosidad de los materiales, fisuras, grietas y juntas) y se acumule en su interior, donde puede ser inhalado en altas concentraciones. La Organización Mundial de la Salud, califica al radón como agente cancerígeno de grado 1. Según este Organismo, el radón es la segunda causa de contracción de cáncer pulmonar detrás del tabaco. Como respuesta a esta alarma, distintos estados ya han elaborado normativas en las que se proponen soluciones para que los niveles de concentración de radón no superen los valores recomendados por los organismos internacionales responsables de la protección radiológica. En España aún no existe normativa de protección frente a este agente cancerígeno causante de numerosas muertes, y es por tal motivo evidente la necesidad de aportar documentación técnica que ayude a las administraciones nacionales y locales a desarrollar dicha normativa para ajustarse a las recomendaciones europeas e internacionales sobre los niveles que no se deben superar y que, por otro lado, ya han contemplado una gran cantidad de países. Como principal aportación de este trabajo se muestran los resultados de reducción de concentración de gas radón de distintas soluciones constructivas enfocadas a frenar la entrada de gas radón al interior de los edificios haciendo uso de técnicas y materiales habituales en el ámbito de la construcción en España. Para ello, se han estudiado las efectividades de dichas soluciones, en lo referente a su capacidad para frenar la inmisión de radón, en un prototipo de vivienda construido al efecto en un terreno con altas concentraciones de radón. Las soluciones propuestas y ensayadas han sido el resultado de una labor de optimización de los sistemas estudiados en la bibliografía con el fin de adaptar las técnicas a los sistemas constructivos habituales en España y en concreto a la situación real del prototipo de vivienda construido en un lugar con contenidos de radón en terreno muy elevados. El trabajo incluye un capítulo inicial con los conceptos básicos necesarios para entender la problemática que supone habitar en espacios con altos contenidos de radón. ABSTRACT The research developed, which has led to the completion of this thesis, deal with the protection of buildings against entry of radon gas and its accumulation in the ocupated spaces. This gas (radon isotope Rn-222) is a radioactive element generated, mainly, in areas with high levels of radio (granitic terrain for example). Its high mobility allows entering in buildings through the enclosure materials of it (porosity of materials, cracks, crevices and joints) and accumulates inside, where it can be inhaled in high concentrations. The World Health Organization describes radon gas as a carcinogen agent in level 1. According to this Agency, radon is the second leading cause of lung cancer behind tobacco. In response to this alarm, some states have developed regulations that propose solutions to reduce radon concentration levels for not exceeding the values recommended by international agencies responsible in radiation protection. In Spain there is still no legislation to protect against this carcinogen element that cause numerous deaths, and for that reason it is evident the need to provide technical documentation to help the national and local governments to develop legislation for reaching the European and international levels recommendations. As the main contribution of this work are the results of reducing radon concentration using different constructive solutions aimed to stop radon entry in buildings, with techniques and materials common in Spain. To do this, effectiveness of such solutions, have been studied in terms of its ability to stop radon entry in a housing prototype built for this purpose in an area with high radon levels. The solutions proposed and tested have been the result of a process of optimization of systems studied in the literature in order to adapt the techniques to Spanish building material and, specifically, to the actual situation of housing prototype built in a place with high contents of radon in soil. The work includes an initial chapter with the basic concepts needed to understand the problem of living in areas with high levels of radon.

Study for the rehabilitation of vernacular architecture with sustainable criteria

This paper assesses rural vernacular heritage established in a warm temperate climate, with dry, hot summer, in São Vicente e Ventosa (SVV), Alentejo, Portugal, and takes part in a larger investigation intending to create rehabilitation guidelines, with sustainable criteria and integration of recent technologies, to improving indoor comfort, and revert the state of deterioration. To further reach this aim, this paper proposes a four phases methodology: data collection, evaluation, simulation and development; a first survey data analysis, including climate data and the adapted comfort climograph and isopleth diagram, allows an understanding of thermal comfort and main constraints in site, as well as suitable bioclimatic strategies for SVV: high thermal inertia for tempering extreme summer conditions and the considerable temperature amplitudes throughout the year, complementarily night ventilation for passive cooling, small-sized window openings and movable shading systems for solar radiation protection. An efficient behaviour in stabilizing indoor temperature swings is revealed.

Diseño y evaluación de un procedimiento on-line para la biorremediación de aguas radiactivas en centrales nucleares

Recientemente se ha demostrado la existencia de microorganismos en las piscinas de almacenamiento de combustible nuclear gastado en las centrales nucleares utilizando técnicas convencionales de cultivo en el laboratorio. Estudios posteriores han puesto de manifiesto que los microorganismos presentes eran capaces de colonizar las paredes de acero inoxidable de las piscinas formando biopelículas. Adicionalmente se ha observado la capacidad de estas biopelículas de retener radionúclidos, lo que hace pensar en la posibilidad de utilizarlas en la descontaminación de las aguas radiactivas de las piscinas. En la presente tesis se plantea conocer más profundamente la biodiversidad microbiana de las biopelículas utilizando técnicas de biología molecular como la clonación, además de desarrollar un sistema de descontaminación a escala piloto con el objetivo de valorar si el proceso podría resultar escalable a nivel industrial. Para ello se diseñaron y fabricaron dos biorreactores en acero inoxidable compatibles con las condiciones específicas de seguridad sísmica y protección frente a la radiación en la zona controlada de una central nuclear. Los biorreactores se instalaron en la Central Nuclear de Cofrentes (Valencia) en las proximidades de las piscinas de almacenamiento de combustible nuclear gastado y precediendo a las resinas de intercambio iónico, de forma que reciben el agua de las piscinas permitiendo el análisis in situ de la radiación eliminada del agua de las mismas. Se conectó una lámpara de luz ultravioleta a uno de los biorreactores para poder comparar el desarrollo de bipelículas y la retención de radiactividad en ambas condiciones. En estos biorreactores se introdujeron ovillos de acero inoxidable y de titanio que se extrajeron a diversos tiempos, hasta 635 días para los ovillos de acero inoxidable y hasta 309 días para los ovillos de titanio. Se analizaron las biopelículas desarrolladas sobre los ovillos por microscopía electrónica de barrido y por microscopía de epifluorescencia. Se extrajo el ADN de las biopelículas y, tras su clonación, se identificaron los microorganismos por técnicas independientes de cultivo. Asimismo se determinó por espectrometría gamma la capacidad de las biopelículas para retener radionúclidos. Los microorganismos radiorresistentes identificados pertenecen a los grupos filogenéticos Alpha-proteobacteria, Gamma-proteobacteria, Actinobacteria, Deinococcus-Thermus y Bacteroidetes. Las secuencias de estos microorganismos se han depositado en el GenBank con los números de acceso KR817260-KR817405. Se ha observado una distribución porcentual ligeramente diferente en relación con el tipo de biorreactor. Las biopelículas han retenido fundamentalmente radionúclidos de activación. La suma de Co-60 y Mn-54 ha llegado en ocasiones al 97%. Otros radionúclidos retenidos han sido Cr-51, Co-58, Fe-59, Zn-65 y Zr-95. Se sugiere un mecanismo del proceso de retención de radionúclidos relacionado con el tiempo de formación y desaparición de las biopelículas. Se ha valorado que el proceso escalable puede ser económicamente rentable. ABSTRACT The existence of microorganisms in spent nuclear fuel pools has been demonstrated recently in nuclear power plants by using conventional microbial techniques. Subsequent studies have revealed that those microorganisms were able to colonize the stainless steel pool walls forming biofilms. Additionally, it has been observed the ability of these biofilms to retain radionuclides, which suggests the possibility of using them for radioactive water decontamination purposes. This thesis presents deeper knowledge of microbial biofilms biodiversity by using molecular biology techniques such as cloning, and develops a decontamination system on a pilot scale, in order to assess whether the process could be scalable to an industrial level. Aiming to demonstrate this was feasible, two stainless steel bioreactors were designed and manufactured, both were compatible with seismic and radiation protection standards in the controlled zone of a nuclear plant. These bioreactors were installed in the Cofrentes Nuclear Power Plant (Valencia) next to the spent nuclear fuel pools and preceding (upstream) ion exchange resins. This configuration allowed the bioreactors to receive water directly from the pools allowing in situ analysis of radiation removal. One ultraviolet lamp was connected to one of the bioreactors to compare biofilms development and radioactivity retention in both conditions. Stainless steel and titanium balls were introduced into these bioreactors and were removed after different time periods, up to 635 days for stainless steel balls and up to 309 days for titanium. Biofilms developed on the balls were analyzed by scanning electron microscopy and epifluorescence microscopy. DNA was extracted from the biofilms, was cloned and then the microorganisms were identified by independent culture techniques. Biofilms ability to retain radionuclides was also determined by gamma spectrometry. The identified radioresistant organisms belong to the phylogenetic groups Alphaproteobacteria, Gamma-proteobacteria, Actinobacteria, Deinococcus-Thermus and Bacteroidetes. The sequences of these microorganisms have been deposited in GenBank (access numbers KR817260-KR817405). A different distribution of microorganisms was observed in relation to the type of bioreactor. Biofilms have essentially retained activation radionuclides. Sometimes the sum of Co-60 and Mn-54 reached 97%. Cr-51, Co-58, Fe-59, Zn-65 and Zr-95 have also been retained. A radionuclide retention process mechanism related to biofilms formation and disappearance time is suggested. It has been assessed that the scalable process can be economically profitable.

Radiological impact of cement, concrete and admixtures in Spain

It has been analyzed samples of portland cement (PC) with and without admixtures, samples of calcium aluminate cement (CAC) with different content of Al2O3 and specimens of concrete made with PC and CAC using High Resolution Gamma Spectrometry. The activity concentration index (I) is much less than 0.5 mSv y-1 for all the concrete specimens according to the Radiation protection document 112 of the European Commission. The PC without admixtures (CEM I 52,5 R) and the PC with addition of limestone (CEM II/BL 32,5 N) also have an I value much lower than 0.5 and the PC with the addition of fly ash and blast furnace slag (CEM IV/B (V) 32,5 N and III/A 42.5 N/SR) have an I value close to 0.6. The I value of the CAC used in the manufacture of structural precast concrete is of the order of 1 mSv y-1. Some of the CAC used in refractory concrete reaches a value close to 2 mSv y-1.

Contributos para implementação de um serviço de Imagiologia no Huambo, Angola

O Governo angolano tem realizado investimentos para a aquisição de tecnologias e incentivado investimentos privados no país para melhor tratar os problemas de saúde pública. Na província do Huambo o número de serviços de imagiologia é relativamente baixo, tendo em conta o número de habitantes. Dentre os serviços existentes, grande parte não possui uma estrutura funcional com a proteção radiológica recomendada, contam com poucos profissionais qualificados e os equipamentos não recebem uma manutenção adequada. Neste contexto, o Huambo representa uma região recetiva à instalação de um novo serviço de imagiologia, com capacidade de atender as necessidades dos utentes e profissionais. O presente trabalho objetiva contribuir para a implementação de um serviço de imagiologia no município do Huambo, a ser desenvolvido consoante às recomendações de boas práticas e normas de proteção radiológica, apoiado pela Lei do Investimento Privado.

Enjeux éthiques en radiologie diagnostique : comment la bioéthique peut-elle contribuer à une meilleure radioprotection du patient?

Bien que les technologies d’imagerie soient un acquis réel de la médecine moderne, leur introduction ne semble pas avoir été précédée d’une démarche réflexive suffisante qui aurait permis d’anticiper les multiples enjeux que rencontre la pratique radiologique actuelle. En effet, à force de se focaliser sur les acquis techniques et scientifiques, le cadre de radioprotection en place semble ne pas avoir suffisamment considéré l’apport essentiel que représente la connaissance des aspects sociaux, éthiques et humains que peuvent amener des domaines comme la bioéthique. Cette insuffisance fait en sorte que l’on se retrouve aujourd’hui face à des enjeux importants relatifs à la radioprotection du patient comme la surutilisation des examens radiologiques ou encore le manque d’information des acteurs du milieu face aux risques des rayonnements. Après un état des lieux des enjeux éthiques en radiologie diagnostique ayant un impact sur la radioprotection médicale des patients, un enjeu majeur de la pratique actuelle, qui est la justification inadéquate des prescriptions d’examens radiologiques, sera analysé selon une approche par principes. De cet exercice, visant à démontrer comment l’éthique peut concrètement contribuer à la radioprotection, découle l’impératif d’une vision nouvelle et globale permettant de proposer des pistes de solution aux controverses liées à l’utilisation actuelle de l’imagerie. Dans une perspective de santé des populations, il est important de contribuer à la diminution de la banalisation du recours au rayonnement ionisant dans la pratique médicale diagnostique en alliant bioéthique et radioprotection. Ce projet de recherche se veut être une étape limitée, mais nécessaire dans l’établissement de ce dialogue interdisciplinaire.

Reactor safety conference, jointly sponsored by American Nuclear Society, Atomic Industrial Forum [and] United States Atomic Energy Commission, New York City, October 31, 1957.

Cover title.

Measurement of absorbed dose of neutrons, and of mixtures and gamma rays; recommendations.

At head of title: U.S. Dept. of Commerce. National Bureau of Standards.