An Approach to Establishing Diagnostic Reference Levels in Interventional Pediatric Cardiology from Different Regions of Brazil.

Diagnostic reference levels (DRLs) are a pivotal strategy to be implemented since pediatric interventional cardiology procedures are increasing. This work aimed to propose an initial set of Brazilian DRLs for pediatric interventional diagnostic and therapeutic (D&T) procedures. A retrospective study was carried out in four Brazilian states, distributed across the three regions of the country. Data were collected from pediatric patients undergoing cardiac interventional procedures (CIPs), including their age and anthropometric characteristics, and at least four parameters (number of images, exposure time, air kerma-area product-PKA, and cumulative air kerma). Data from 279 patients undergoing CIPs were gathered (147 diagnostic and 132 therapeutic procedures). There were no significant differences in exposure time and the number of images between the D&T procedures. A wide range of PKA was observed when the therapeutic procedures were compared to diagnostics for all age groups. There were significant differences between the D&T procedures, whether grouping data by patient weight or age. In terms of cumulative air kerma, it was noted that no value exceeded the level to trigger a monitoring process for patients. This study shows that it is possible to adopt them as the first proposal to establish national DRLs considering pediatric patient groups.

Effect of lateral decubitus acquisition in accuracy and lung severity estimation of chest computed tomography in children with suspected COVID-19.

OBJECTIVE: To compare inter-rater reliability, diagnostic accuracy, and extension of pulmonary involvement in children with suspected COVID-19 submitted to supine or supine and lateral decubitus computed tomography imaging. METHODS: Retrospective study carried out between March 2020 and March 2021 with patients submitted to reverse transcription-polymerase chain reaction testing and chest computed tomography. Patients were divided into two groups: supine or supine and lateral decubitus imaging. Standardized reporting systems of computed tomographic findings in COVID-19 and chest computed tomography score were used. RESULTS: One hundred and seventeen patients were enrolled. Moderate to substantial inter-rater reliability was observed for standardized reporting systems (weighted kappa, 0.553-0.764; p<0.001). Inter-rater reliability for the chest computed tomography score was substantial (weighted kappa, 0.620-0.670; p<0.001). Standardized reporting systems failed to predict COVID-19 in children, regardless of additional lateral decubitus imaging (area under the receiver operating characteristic curve, 0.491-0.608). Chest computed tomography scores assigned to lateral decubitus images were significantly lower. CONCLUSION: Additional lateral decubitus imaging does not improve the accuracy of standardized reporting systems of computed tomographic findings in COVID-19 but may provide a more accurate estimation of lung involvement in uncooperative patients.

Effect of lateral decubitus acquisition in accuracy and lung severity estimation of chest computed tomography in children with suspected COVID-19

ABSTRACT Objective To compare inter-rater reliability, diagnostic accuracy, and extension of pulmonary involvement in children with suspected COVID-19 submitted to supine or supine and lateral decubitus computed tomography imaging. Methods Retrospective study carried out between March 2020 and March 2021 with patients submitted to reverse transcription-polymerase chain reaction testing and chest computed tomography. Patients were divided into two groups: supine or supine and lateral decubitus imaging. Standardized reporting systems of computed tomographic findings in COVID-19 and chest computed tomography score were used. Results One hundred and seventeen patients were enrolled. Moderate to substantial inter-rater reliability was observed for standardized reporting systems (weighted kappa, 0.553-0.764; p<0.001). Inter-rater reliability for the chest computed tomography score was substantial (weighted kappa, 0.620-0.670; p<0.001). Standardized reporting systems failed to predict COVID-19 in children, regardless of additional lateral decubitus imaging (area under the receiver operating characteristic curve, 0.491-0.608). Chest computed tomography scores assigned to lateral decubitus images were significantly lower. Conclusion Additional lateral decubitus imaging does not improve the accuracy of standardized reporting systems of computed tomographic findings in COVID-19 but may provide a more accurate estimation of lung involvement in uncooperative patients.

Optimización de la protección en radiología y cardiología intervencionista pediatrica en América Latina y el Caribe (OPRIPALC) / Optimization of protection in pediatric interventional cardiology and radiology in Latin America and the Caribbean (OPRIPALC)

El objetivo del presente artículo ha sido describir el programa "Optimización de la Protección en Radiología Intervencionista Pediátrica en América Latina y el Caribe" (OPRIPALC) que nace el año 2018 como respuesta conjunta de la Organización Panamericana de la Salud y la Organización Mundial de la Salud, en cooperación con el Organismo Internacional de Energía Atómica, para colaborar con sus Estados miembros en asegurar que las exposiciones a la radiación de los pacientes pediátricos sean las mínimas necesarias durante los procedimientos intervencionistas. Actualmente, hay 18 centros de los siguientes 10 países que participan: Argentina, Brasil, Chile, Colombia, Costa Rica, Cuba, Ecuador, México, Perú y Uruguay. Para el desarrollo del programa se plantean una serie de objetivos, productos, actividades y resultados esperados. La puesta en marcha de la WEB de OPRIPALC ha significado un instrumento muy válido para seguir la información actualizada del programa. Un programa actualizado de formación en radioprotección para los profesionales implicados en el programa, se está realizando por medio de "webinars". Se deberá seguir actuando en la aplicación del programa de control de calidad básico para los equipos de rayos X participantes y validar los valores de los Niveles de Referencia para Diagnóstico (NRDs). Se propone formar un equipo de trabajo entre los Físicos Médicos y Tecnólogos Médicos participantes de OPRIPALC para implicarse en las pruebas de control básicas que todos los centros debieran realizar. Se han presentado algunos resultados iniciales de OPRIPALC en eventos científicos internacionales. Se está avanzando en proponer unos primeros valores sobre NRDs en procedimientos de intervencionismo cardiológico pediátrico por bandas de edad y peso. OPRIPALC es una de las pocas iniciativas de carácter regional para obtener valores de NRDs en procedimientos intervencionistas pediátricos. Se espera que tanto los valores de referencia como la metodología empleada en OPRIPALC, puedan ser utilizados en otras regiones del mundo.

The objective of this article has been to describe the program "Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean" (OPRIPALC) that was born in 2018 as a joint response of the Pan American Health Organization and the World Organization of the Health, in cooperation with the International Atomic Energy Agency, to collaborate with its member states in ensuring that radiation exposures of pediatric patients are the minimum necessary during interventional procedures. Currently, there are 18 centers from the following 10 countries participating: Argentina, Brazil, Chile, Colombia, Costa Rica, Cuba, Ecuador, Mexico, Peru and Uruguay. For the development of the program, a series of objectives, products, activities and expected results are proposed. The launch of the OPRIPALC WEBSITE has been a very valid instrument for following up-to-date information on the program. An updated training program in radiation protection for the professionals involved in the program is being carried out through webinars. It should continue acting in the application of the basic quality control program for the participating X-ray equipment and validate the values of the Diagnostic Reference Levels (DRLs). It is proposed to form a work team among the OPRIPALC participating medical physicists to get involved in the basic control tests that all centers should carry out. Some initial results of OPRIPALC have been presented at international scientific events. Progress is being made in proposing first values on DRLs in pediatric cardiac intervention procedures by age and weight bands. OPRIPALC is one of the few regional initiatives to obtain DRLs values in pediatric interventional procedures. It is expected that both the reference values and the methodology used in OPRIPALC can be used in other regions of the world.

Image evaluation and breast density categories as a function of mammary positioning in full-field digital mammography.

BACKGROUND: Appropriate mammary positioning is an important factor in optimizing image quality in mammography (MMG). PURPOSE: To study the correlation of quality criteria and breast density classification proposed by the American College of Radiology (ACR) and European Guidelines and its influence to achieve a proper positioning, therefore an adequate MMG. MATERIAL AND METHODS: A total of 128 routine MMG examinations were reviewed for the definition of breast composition parenchyma and assessment of several quality criteria proposed by the ACR and European Guidelines to achieve an adequate MMG. Adequate MMG was defined as a difference between the posterior nipple line (PNL), difference of the mediolateral oblique (MLO) and craniocaudal (CC) incidences > 1 cm. The quality criteria were analyzed as a function of correlation coefficient in order to evaluate the individual impact of each factor and analysis of variance (ANOVA) for all criteria. Receiver operating characteristic (ROC) curves were plotted to evaluate the performance of the criteria on each type of parenchyma. RESULTS: Negative correlation of fatty breasts and visibility of the mammary angle, a greater number of skin folds and PNL > 1 cm (r < 0). Dense MMG presented less visibility of the lateral tissue compared with other categories. Area under the curve of ROC analysis revealed values of 53.1% and 54.7% for the right and left breasts, respectively. CONCLUSION: Several factors influenced in the MMG process, but we find that breast parenchyma has a substantial role in affecting these criteria and therefore a correct position for diagnosis, which could compromise MMG diagnostic performance.

EVALUATION OF THE RADIATION EXPOSURE IN SEQUENTIAL HEAD TOMOGRAPHIC EXAMS OF PATIENTS WITH TRAUMATIC BRAIN INJURY AND DECOMPRESSIVE CRANIECTOMY.

Brain trauma patients who underwent decompressive craniectomy make several computed tomography (CT) scans until cranioplasty. Despite several recommendations to avoid unnecessary radiological exposure, few studies systematically analyzed the technical parameters employed. CT exams of 14 patients were retrospectively analyzed to find display field of view (DFOV), dose length product (DLP), volume computed tomography dose index (CTDIvol) and effective dose (ED). The values obtained were: 120 kVp [95% confidence interval (CI) of 0.5], 297 mA (95% CI of 5.6), scan range 20.8 cm (95% CI of 1.3), DFOV 24.5 cm (95% CI of 1.6), CTDIvol 67.5 mGy (95% CI of 10.17), DLP 1404.8 mGy.cm (95% CI of 235.0) and ED 2.9 mSv (95% CI of 0.5). In conclusion, these values were above the recommendations of several guidelines and raise concern for excessive radiological exposure in trauma patients despite being previously reported in the literature.

Monitoramento da radioatividade alfa relacionada ao radônio-222 em águas de poços da região metropolitana de Curitiba (PR) / Alpha radioactivity monitoring related to radon-222 in water from wells in metropolitan area of Curitiba (PR), Brazil

O objetivo desta pesquisa foi avaliar os níveis de concentração de radônio 222Rn em águas de poços da região metropolitana de Curitiba, Paraná. O trabalho apresenta os resultados das concentrações das medidas feitas em águas de poços da região. As concentrações de 222Rn nas amostras das águas de poços foram medidas por meio do monitor de radônio AlphaGUARD. Os cálculos das concentrações de atividade iniciais de radônio na água foram feitos a partir da curva de decaimento do 222Rn e do equilíbrio secular entre o 222Rn e o 226Ra, observados depois de 30 dias. Os resultados indicaram que cerca de 70% dos valores das concentrações de 222Rn ficaram acima do valor recomendado pela USEPA, de 11,1 Bq.L-1, representando risco radiológico causado por este radionuclídeo. O estudo de caso apresentado mostrou que medidas prévias de radônio são recomendadas para que um projeto de construção seja implementado. No caso em questão, observa-se que as concentrações de radônio diminuem cerca de 56% na primeira caixa d'água e 83% na segunda em relação ao poço. Esse fato mostra que as ações para mitigação de radônio são viáveis e não exigem grandes modificações nos sistemas usuais da construção civil.

This research objective was to assess the level of randon-222 concentration in well water of the metropolitan region of Curitiba, Paraná. Current work presents the results of indoor 222Rn activity ground water samples from artesian wells from aquifers of the region. The studies of radon activity in water were performed using the radon detector AlphaGUARD. The calculations of initial radon activity in water were done considering the 222Rn decay correction as well as equilibrium level of 222Rn and 226Ra observed after 30 days of measurements. Obtained results show that about 70% of measured activity levels of 222Rn are higher than the recommended value of 11.1 Bq.L-1, which represent the risk for the human health associated with this radionuclide. The case study showed that previous measurements of radon are recommended for a construction project is implemented. In this case, it is observed that the radon concentrations decrease about 56% in the first water tank and 83% in the second water tank over the well. This fact shows that the actions for mitigation of radon are viable and do not require major modifications to the usual systems of construction.

Comparison of SRIM, MCNPX and GEANT simulations with experimental data for thick Al absorbers.

Proton computerized tomography deals with relatively thick targets like the human head or trunk. In this case precise analytical calculation of the proton final energy is a rather complicated task, thus the Monte Carlo simulation stands out as a solution. We used the GEANT4.8.2 code to calculate the proton final energy spectra after passing a thick Al absorber and compared it with the same conditions of the experimental data. The ICRU49, Ziegler85 and Ziegler2000 models from the low energy extension pack were used. The results were also compared with the SRIM2008 and MCNPX2.4 simulations, and with solutions of the Boltzmann transport equation in the Fokker-Planck approximation.

GEANT4 simulations for low energy proton computerized tomography.

This work presents the recent results of computer simulations for the low energy proton beam tomographic scanner installed at the cyclotron CV-28 of IEN/CNEN. New computer simulations were performed in order to adjust the parameters of previous simulation within the first experimental results and to understand some specific effects that affected the form of the final proton energy spectra. To do this, the energy and angular spread of the initial proton beam were added, and the virtual phantom geometry was specified more accurately in relation to the real one. As a result, a more realistic view on the measurements was achieved.

Avaliação da exposição ocupacional em procedimentos de hemodinâmica / Evaluation of occupational exposure in hemodynamic procedures

OBJETIVO: Avaliar a dose efetiva recebida pelos trabalhadores envolvidos na realização de procedimentos de hemodinâmica, de forma a estabelecer parâmetros comparativos entre os dados obtidos com uma câmara de ionização e pelos dosímetros usados para monitoração individual. MATERIAIS E MÉTODOS: A avaliação foi desenvolvida em um serviço de hemodinâmica, sendo que os testes constaram da medida do taxa de kerma no ar no ambiente real de trabalho, na posição ocupada por médicos e enfermeiros, com e sem a utilização de barreira plumbífera de proteção. Foi levado em consideração o número de exames realizados no serviço e foram selecionados as projeções e parâmetros radiográficos mais utilizados. Para a estimativa da dose efetiva foram utilizados fatores de conversão encontrados na literatura. RESULTADOS: Os valores encontrados em dose efetiva e de dosimetria são consistentes. Observou-se, ainda, que o uso da barreira protetora plumbífera reduz em até 97 por cento a dose recebida pelo profissional, devendo esta ser utilizada na rotina de exames. CONCLUSAO: Os valores apresentados são representativos, não podendo ser assumidos como reprodução das condições de monitoração individual, mas são válidos para comparações e orientação na otimização das doses.

Elaboração de um programa computacional para avaliação e controle de serviços de radiologia médica de médio porte, de acordo com as diretrizes de proteção radiológica do Ministério da Saúde / Development of a computational program for evaluation and control of medium size medical radiological facilities, according to the radiological protection directives of the Brazilian Ministry of Health

Este trabalho apresenta o resultado do estudo para elaboração de um programa computacional para avaliação e controle de serviços de radiologia médica de médio porte, de acordo com as recentes diretrizes de proteção radiológica do Ministério da Saúde. A rotina do Departamento de Radiologia do Hospital São Vicente de Paulo, Passo Fundo, RS, foi analisada, e a partir desta análise foi desenvolvido um programa computacional utilizando-se ferramentas de computação padrão Windows. O programa, chamado de "Sistema Radiológico", foi implementado e testado com dados e medições, ficando comprovado que a metodologia permite o acompanhamento dos requisitos da Portaria nº 453 do Ministério da Saúde e possibilita ganho de eficiência em diversas atividades.

Laboratório de tomografia computadorizada e raios-x convencional do Cefet-PR / Computadorized tomography laboratory and conventional x-rays of Cefet-PR

O presente trabalho diz respeito a uma das atividades de pesquisa realizada no CEFET-PR. Esta envolve a formação de um Laboratório de Controle de Qualidade em Imagens Radiológicas, a montagem de um Tomógrafo Computadorizado e um equipamento de Raios-X Convencional, doados à nossa Instituição. Uma vez instalados, buscar-se-á uma modernização das diversas partes dos equipamentos, incluindo os seus sistemas de detecção, software e hardware, com o propósito de aumentar a resolução e qualidade da imagem.

Presented Paper is concerned with the development of X-ray Laboratory at CEFET-PR organized recently. Our activity is focusing mainly at advancement and hospital practice application of lmage Quality Program for X-ray and Tomograph scanning. At the same time we are working on modernization of installed Xray equipment donated to our lnstitution. We deal with X-ray detectors, software and hardware, which configuration and parameters affect the image quality as well.