Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 551
Filter
1.
Rev. urug. cardiol ; 38(1): e202, 2023. graf, tab
Article in Spanish | LILACS, UY-BNMED, BNUY | ID: biblio-1450408

ABSTRACT

Introducción: la mortalidad posoperatoria ha sido el indicador principal de los resultados a corto y mediano plazo en la evaluación de la cirugía cardíaca. Una forma de analizar dicho evento es mediante los modelos de ajuste del riesgo que identifican variables que predicen su ocurrencia. Uno de los más utilizados es el EuroSCORE I que pro-porciona la probabilidad de morir de cada individuo y que está constituido por 18 variables de riesgo. Objetivos: presentar los resultados de la aplicación y la validación del modelo EuroSCORE I en Uruguay entre los años 2003 y 2020. Metodología: inicialmente se desarrolló una validación externa del EuroSCORE I en la población uruguaya adulta tomando como población de referencia la intervenida entre los años 2003 y 2006. Una vez que se validó el EuroSCORE I, este se aplicó prospectivamente durante los años 2007 al 2020 en su versión original y con el ajuste desarrollado con población del período 2003-2006. Resultados: la aplicación del modelo original encontró que hubo 5 años en los que la razón de mortalidad observada y esperada (MO/ME) fue significativamente mayor que 1. En el período 2007-2020 el EuroScore I no calibró en 6 oca-siones, y fue aplicada la versión ajustada en la evaluación de las instituciones de medicina altamente especializada. La aplicación del modelo ajustado mostró una buena calibración para el período 2007-2020, salvo en el año 2013, y mostró una buena discriminación (área bajo la curva ROC) en todo el período evaluado. Conclusiones: las escalas de riesgo son herramientas metodológicas y estadísticas que tienen gran utilidad para la toma de decisiones en salud. Este trabajo tiene como fortaleza el de presentar datos nacionales aplicando un modelo de riesgo ampliamente utilizado en todo el mundo, lo que nos permite comparar nuestros resultados con los obte-nidos a nivel internacional (EuroSCORE I logístico original) y, por otro lado, evaluar la performance comparativa interna a lo largo de un largo período de tiempo (EuroSCORE I logístico ajustado). Para el futuro resta el desafío de comparar estos resultados, ya sea con un modelo propio o con otros internacionales de elaboración más reciente.


Introduction: postoperative mortality has been the main indicator of short- and medium-term results in the eva luation of cardiac surgery. One way to analyze such outcomes is through risk adjustment models that identify varia bles that predict the occurrence. One of the most used is the EuroSCORE I, which provides the probability of death for each individual and is made up of 18 risk variables. Objectives: present the results of the application and validation of the EuroSCORE I model in Uruguay between 2003 and 2020. Methodology: initially, an external validation of the EuroSCORE I was developed in the Uruguayan adult popula tion, taking as reference population the intervened population between 2003 and 2006. Once the EuroSCORE I was validated, it was applied prospectively during the years 2007 to 2020 in its original version and with the adjustment developed with the population of the period 2003 to 2006. Results: the application of the original model found that there were 5 years during which the observed versus ex pected mortality ratio (OM/ME) was significantly greater than 1. In the period 2007 to 2020, the EuroScore I did not calibrate on 6 occasions, the adjusted version being applied in the evaluation of highly specialized medicine institu tions. The application of the adjusted model showed a good calibration for the period 2007-2020 except in the year 2013 and showed good discrimination (area under the ROC curve) throughout the evaluated period. Conclusions: risk scales are methodological and statistical tools that are very useful for decision-making in health care. This work has the strength of presenting national data applying a risk model widely used across the world, which allows it to be compare with results at an international level (original logistical Euroscore I) and, on the other hand, to evaluate the internal comparative performance over long period of time (adjusted logistic Euroscore I). Up next is the challenge of comparing these results either with our own model or with other more recent international ones.


Introdução: a mortalidade pós-operatória tem sido o principal indicador de resultados a curto e médio prazo na avaliação da cirurgia cardíaca. Uma forma de analisar esse evento é por meio de modelos de ajuste de risco que identificam variáveis que predizem a ocorrência do evento. Um dos mais utilizados é o EuroSCORE I, que fornece a probabilidade de morrer para cada indivíduo e é composto por 18 variáveis de risco. Objetivos: apresentar os resultados da aplicação e validação do modelo EuroSCORE I no Uruguai entre os anos de 2003 e 2020. Metodologia: inicialmente, foi realizada uma validação externa do EuroSCORE I na população uruguaia adulta, tomando como referência a população operada entre 2003 e 2006. Uma vez validado o EuroSCORE I, foi aplicado prospectivamente durante os anos de 2007 a 2020 em sua versão original e com o ajuste desenvolvido com a popu lação do período de 2003 a 2006. Resultados: a aplicação do modelo original constatou que houve 5 anos em que a razão de mortalidade observada versus esperada (MO/ME) foi significativamente maior que 1. No período de 2007 a 2020, o EuroScore I não calibrou em 6 ocasiões, sendo a versão ajustada aplicada na avaliação de instituições médicas altamente especializadas. A aplicação do modelo ajustado mostrou uma boa calibração para o período 2007-2020 exceto no ano de 2013 e apre sentou boa discriminação (área sob a curva ROC) em todo o período avaliado. Conclusões: as escalas de risco são ferramentas metodológicas e estatísticas muito úteis para a tomada de decisões em saúde. O ponto forte deste trabalho é apresentar dados nacionais aplicando um modelo de risco amplamente uti lizado em todo o mundo, que permite comparar com resultados a nível internacional (original Logistic Euroscore I) e, por outro lado, avaliar o comparativo interno desempenho durante um longo período de tempo (Euroscore Logístico I ajustado). Para o futuro, fica o desafio de comparar esses resultados, seja com um modelo próprio ou com outros internacionais de elaboração mais recente.


Subject(s)
Humans , Risk Assessment/methods , Cardiac Surgical Procedures/mortality , Uruguay , Calibration , Logistic Models , ROC Curve , Validation Study
2.
Journal of Southern Medical University ; (12): 76-84, 2023.
Article in Chinese | WPRIM | ID: wpr-971497

ABSTRACT

OBJECTIVE@#To compare the predictive ability of two extended Cox models in nonlinear survival data analysis.@*METHODS@#Through Monte Carlo simulation and empirical study and with the conventional Cox Proportional Hazards model and Random Survival Forests as the reference models, we compared restricted cubic spline Cox model (Cox_RCS) and DeepSurv neural network Cox model (Cox_DNN) for their prediction ability in nonlinear survival data analysis. Concordance index was used to evaluate the differentiation of the prediction results (a larger concordance index indicates a better prediction ability of the model). Integrated Brier Score was used to evaluate the calibration degree of the prediction (a smaller index indicates a better prediction ability).@*RESULTS@#For data that met requirement of the proportion risk, the Cox_RCS model had the best prediction ability regardless of the sample size or deletion rate. For data that failed to meet the proportion risk, the prediction ability of Cox_DNN was optimal for a large sample size (≥500) with a low deletion (< 40%); the prediction ability of Cox_RCS was superior to those of other models in all other scenarios. For example data, the Cox_RCS model showed the best performance.@*CONCLUSION@#In analysis of nonlinear low maintenance data, Cox_RCS and Cox_DNN have their respective advantages and disadvantages in prediction. The conventional survival analysis methods are not inferior to machine learning or deep learning methods under certain conditions.


Subject(s)
Proportional Hazards Models , Survival Analysis , Calibration , Computer Simulation , Data Analysis
3.
Journal of Southern Medical University ; (12): 1241-1247, 2023.
Article in Chinese | WPRIM | ID: wpr-987041

ABSTRACT

OBJECTIVE@#To construct an inherent interpretability machine learning model as an explainable boosting machine model (EBM) for predicting one-year risk of death in patients with severe ischemic stroke.@*METHODS@#We randomly divided the data of 2369 eligible patients with severe ischemic stroke in the MIMIC-Ⅳ(2.0) database, who were admitted in ICU in 2008 to 2019, into a training dataset (80%) and a test dataset (20%), and assessed the prognosis of the patients using the EBM model. The prediction performance of the model was evaluated by calculating the area under the receiver operating characteristic (AUC) curve. The calibration curve and Brier score were used to evaluate the degree of calibration of the model, and a decision curve was generated to assess the net clinical benefit.@*RESULTS@#The EBM model constructed in this study had good discrimination power, calibration and net benefit, with an AUC of 0.857 (95% CI: 0.831-0.887) for predicting prognosis of severe ischemic stroke. Calibration curve analysis showed that the standard curve of the EBM model was the closest to the ideal curve. Decision curve analysis showed that the model had the greatest net benefit rate at the prediction probability threshold of 0.10 to 0.80. The top 5 independent predictive variables based on the EBM model were age, SOFA score, mean heart rate, mechanical ventilation, and mean respiratory rate, whose significance scores ranged from 0.179 to 0.370.@*CONCLUSION@#This EBM model has a good performance for predicting the risk of death within one year in patients with severe ischemic stroke and allows clinicians to better understand the contributing factors of the patients' outcomes through the model interpretability.


Subject(s)
Humans , Ischemic Stroke , Calibration , Databases, Factual , Intensive Care Units , Machine Learning
4.
Journal of Southern Medical University ; (12): 1233-1240, 2023.
Article in Chinese | WPRIM | ID: wpr-987040

ABSTRACT

OBJECTIVE@#To propose a sensitivity test method for geometric correction position deviation of cone-beam CT systems.@*METHODS@#We proposed the definition of center deviation and its derivation. We analyzed the influence of the variation of the three-dimensional spatial center of the steel ball point, the projection center and the size of the steel ball point on the deviation of geometric parameters and the reconstructed image results by calculating the geometric correction parameters based on the Noo analytical method using the FDK reconstruction algorithm for image reconstruction.@*RESULTS@#The radius of the steel ball point was within 3 mm. The deviation of the center of the calibration parameter was within the order of magnitude and negligible. A 10% Gaussian perturbation of a single pixel in the 3D spatial coordinates of the steel ball point produced a deviation of about 3 pixel sizes, while the same Gaussian perturbation of the 2D projection coordinates of the steel ball point produced a deviation of about 2 pixel sizes.@*CONCLUSION@#The geometric correction is more sensitive to the deviation generated by the three-dimensional spatial coordinates of the steel ball point with limited sensitivity to the deviation generated by the two-dimensional projection coordinates of the steel ball point. The deviation sensitivity of a small diameter steel ball point can be ignored.


Subject(s)
Algorithms , Calibration , Cone-Beam Computed Tomography , Steel
5.
Article in English | LILACS, BBO | ID: biblio-1448795

ABSTRACT

ABSTRACT Objective: To evaluate an imaging protocol for use as a diagnostic and calibration tool for dentists before and after practical activity. Material and Methods: Thirty photos of children's teeth with or without changes in dental enamel were selected and evaluated by a group of experienced dentists previously calibrated to establish the diagnosis defined as the gold standard. After instructions, the images were shown to a group of postgraduate dentists for free identification of dental changes. Subsequently, a lecture on molar incisor hypomineralization (MIH) was carried out, and, at 14 days and all calibration was performed using the criteria previously. The retest was performed at 28 days. After experience in clinical activity in the following two weeks, the post-test was performed at 49 days. Data were analyzed using Cohen's kappa coefficient. Results: Theoretical learning on the subject showed low inter-examiner agreement when the diagnosis of defects was made from images obtained from intraoral photographs. After clinical practice, there was greater intra-examiner agreement. After theoretical training, dentists started to identify different types of enamel alteration, although with low agreement between them. Conclusion: Clinical experience in theoretical and imaging training favored the identification of defects. However, it is necessary to improve the protocol to establish a reliable and viable diagnostic method for calibration in MIH.


Subject(s)
Humans , Male , Female , Dental Enamel Hypoplasia/diagnostic imaging , Molar Hypomineralization/diagnostic imaging , Calibration/standards , Photography, Dental/instrumentation
6.
Aval. psicol ; 21(2): 127-139, abr.-jun. 2022. il, tab
Article in Portuguese | LILACS, INDEXPSI | ID: biblio-1447458

ABSTRACT

A Bateria de Provas de Raciocínio (BPR-5) é um instrumento bastante utilizado para avaliação da inteligência no Brasil, possuindo três formas: infantil (1º ao 6º ano do Ensino Fundamental), Forma A (7º ao 9º ano do Ensino Fundamental) e Forma B (Ensino Médio e Superior). Visando a possibilidade de comparar os resultados entre sujeitos que respondem a formas diferentes, o presente estudo objetivou: (a) calibrar os itens das três formas pelo modelo de Rasch, realizando a equalização por itens comuns de modo a obter uma escala equiparável para as três formas, (b) atualizar as normas expandindo a representatividade das amostras e produzindo-se normas para diferentes combinações de idade, escolaridade e sexo, (c) descrever padrões de desenvolvimento da inteligência a partir da escala, comum, produzida entre 6 e 52 anos. Dois estudos foram relatados, o primeiro sobre a calibração dos parâmetros segundo o modelo de Rasch indicando um bom ajuste ao modelo. O segundo estudo exemplificou a utilização de regressão múltipla para criação de normas para testes psicológicos, considerando as variáveis idade, escolaridade e sexo como preditoras dos escores na BPR-5. Essas três variáveis tiveram efeitos significativos explicando 8% (Raciocínio Abstrato), 13% (Raciocínio Verbal), 12% (Raciocínio Espacial), 8% (Raciocínio Numérico) e 22% (Raciocínio Mecânico).(AU)


The Reasoning Tests Battery (BPR-5) is widely used in Brazil for the assessment of intelligence. It has three different forms: children (1st to 6th grade of elementary school), Form A (7th to 9th grade of elementary school) and Form B (high school and higher education). This study describes the steps followed to create a common metric across the forms. It aimed to: (a) calibrate the items of the three forms using Rasch model, link items and equate subjects' scores across forms using the anchoring of common items method, (b) update the norms by expanding the representativeness of the samples by producing norms for different combinations of age, education and sex, and (c) describe the developmental patterns of the BPR-5 subtests across a wide age range, from 6 to 52 years. We present two studies, the first reporting the calibration of item and person parameters with the Rasch model and a good fit to the model. The second illustrated the use of multiple regression analysis to create norms for the psychological tests considering the variables age, education and gender as predictors of the BPR-5 scores. These three variables had significant effects explaining 8% (Abstract Reasoning), 13% (Verbal Reasoning), 12% (Spatial Reasoning), 8% (Numerical Reasoning) and 22% (Mechanical Reasoning) of the variance. (AU)


La Batería de Pruebas de Razonamiento (BPR-5) es un instrumento muy utilizado para la evaluación de la inteligencia en Brasil, disponiendo de tres formas: infantil (1° al 6° año de la Enseñanza Fundamental), Forma A (7° al 9° año de la Enseñanza Fundamental) y Forma B (Bachillerato y Educación Superior). Teniendo como finalidad la posibilidad de comparar los resultados entre sujetos que responden a diferentes versiones, el presente estudio tuvo como objetivo: (a) calibrar los ítems de las tres formas por el modelo de Rasch, realizando la igualación por ítems comunes a fin de obtener una escala equiparable para las tres formas, (b) actualizar las normas ampliando la representatividad de las muestras y produciendo normas para diferentes combinaciones de edad, escolarización y sexo, (c) describir patrones de desarrollo de la inteligencia a partir de la escala, común, producida entre los 6 y los 52 años. Dos estudios fueron reportados, el primer sobre la calibración de los parámetros de acuerdo con el modelo de Rasch, indicando un buen ajuste al modelo. El segundo estudio ejemplificó la utilización de regresión múltiple para crear normas para tests psicológicos, considerando las variables edad, educación y sexo como predictivos de los escores en el BPR-5. Esas tres variables tuvieron efectos significativos explicando 8% (Razonamiento Abstracto), 13% (Razonamiento Verbal), 12% (Razonamiento Espacial), 8% (Razonamiento Numérico), y 22% (Razonamiento Mecánico).(AU)


Subject(s)
Humans , Male , Female , Child , Adolescent , Adult , Middle Aged , Young Adult , Intelligence , Intelligence Tests/standards , Psychometrics , Calibration/standards , Regression Analysis , Educational Status , Age and Sex Distribution
7.
J. health med. sci. (Print) ; 8(1): 45-50, ene.-mar. 2022. ilus, graf, tab
Article in English | LILACS | ID: biblio-1395758

ABSTRACT

Radiation absorbed doses to organs outside the radiation therapy treatment beam can be significant and therefore of clinical interest. Two sets of out-of-beam measurements were performed measuring the leak dose and the scattered dose, at 5 points within the accelerator components (accelerator tube and collimator) and at 21 points on the equipment and surroundings based on a positioning scheme. For this purpose, 52 Optically Stimulated Luminescence (OSL) dosimeters were used in a latest generation helical linear accelerator. Of the 200 cGy fired at a cheese-like phantom, 0.332% of the out-of-beam dose contribution was found to come from the leak and 0.784% was transformed into scattering. For these dose values, estimates of the risk of second tumors in long-term survivors indicate a reduced probability of acquiring a second secondary radiation malignancy, based on information from the 1990 BEIR Committee report.


La dosis absorbida de radiación a órganos fuera del haz de tratamiento de radioterapia puede ser significativa y, por lo tanto, de interés clínico. Se realizaron dos sets de mediciones fuera del haz para determinar la dosis de fuga y la dosis dispersa, en 5 puntos dentro de los componentes del acelerador (tubo de aceleración y colimador) y 21 puntos en el equipo y alrededores basado en un esquema de posicionamiento. Para este fin se utilizaron 52 dosímetros de luminiscencia estimulada ópticamente (OSL, Optically Stimulated Luminescence), en un acelerador lineal helicoidal de última generación. De los 200 cGy disparados a un maniquí tipo queso, se encontró que el 0.332% de la contribución de dosis fuera del haz provenía de la fuga y 0.784% se transforma en dispersión. Para estos valores de dosis, las estimaciones del riesgo de segundos tumores en los supervivientes a largo plazo indican una reducida probabilidad de contraer una segunda malignidad por radiación secundaria, según la información del informe del Comité BEIR de 1990.


Subject(s)
Humans , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Intensity-Modulated/methods , Optically Stimulated Luminescence Dosimetry , Radiometry/instrumentation , Thermoluminescent Dosimetry , Calibration , Luminescence , Luminescent Measurements
8.
Med. lab ; 26(2): 159-175, 2022. tab
Article in Spanish | LILACS | ID: biblio-1393231

ABSTRACT

Las mediciones confiables, trazables metrológicamente y comparables proporcionan la base racional para la evaluación de la calidad de un resultado y el fortalecimiento de las redes de laboratorios clínicos, lo cual permite mejorar la calidad de atención y la seguridad del paciente. En este documento se revisan los principios básicos que deben seguirse para garantizar la trazabilidad de las mediciones del laboratorio clínico, las ventajas de utilizar métodos trazables, el impacto de no hacerlo, y se discuten las principales limitaciones para relacionar las mediciones con los estándares de medición de referencia apropiados


Reliable, metrologically traceable, and comparable measurements provide the rationale for evaluating the quality of a result and strengthening clinical laboratory networks, thereby improving quality of care and patient safety. This document reviews the basic principles that must be followed to ensure the traceability of clinical laboratory results, the advantages of using traceable methods, the impact of not doing so, and the main limitations in relating measurements to appropriate reference standards


Subject(s)
Data Accuracy , Reagent Kits, Diagnostic , Reference Standards , Calibration , Equipment and Supplies , International System of Units
9.
Dent. press endod ; 11(3): 40-45, Sept-Dec.2021. Tab, Ilus
Article in English | LILACS | ID: biblio-1379003

ABSTRACT

Objetivo: O objetivo desse artigo foi avaliar a precisão das porções milimetrada e calibradora das réguas endodônticas, e avaliar a regularidade da superfície dos orifícios calibradores. Métodos: A porção milimetrada das réguas Angelus, Maillefer, Maquira, Microdont e Prisma foi avaliada com paquímetro eletrônico digital. Os orifícios calibradores da Maillefer, Prisma e Angelus foram medidos com um projetor de perfil. A regularidade da superfície dos orifícios calibradores foi classificada em S1 ­ sem irregularidades ou S2 ­ com regularidades. A análise de precisão das porções milimetrada e calibradora foi realizada com o teste t (p=0,05); e as frequências dos tipos de superfície, com o teste do qui-quadrado (p<0,05). Resultados: A Maillefer foi a única régua endodôntica com precisão em todos os comprimentos e orifícios. A Prisma apresentou estatisticamente mais orifícios do tipo S2, quando comparada com outras réguas endodônticas avaliadas (p<0,05). Não houve diferença estatisticamente significativa entre Angelus e Maillefer (p>0,05). Conclusão: A Maillefer apresentou precisão nas porções milimetrada e calibradora. As réguas endodônticas da Angelus não foram precisas em nenhum comprimento da parte milimetrada e não foram precisas na maioria dos orifícios calibradores. A régua endodôntica Prisma mostrou significativamente mais orifícios calibradores com irregularidades na superfície do que Angelus e Maillefer. Destaca-se a necessidade de controle de qualidade e padrões específicos para fabricação das réguas endodônticas (AU).


Objective: The aim was to evaluate the accuracy of the millimeter and calibration portion and evaluate the regularity of the calibrator orifice surfaces of the endodontic rulers. Methods: The millimeter portion of the Angelus, Maillefer, Maquira, Microdont and Prisma rulers was evaluated with an electronic digital caliper. The calibration holes of the Maillefer, Prisma and Angelus were measured with Profile Projector. The surface regularity of calibration holes was evaluated and classified in S1- without irregularities and S2- with irregularities. The accuracy analysis of the millimeter and calibration was performed with T-Test (p=0.05) and the frequencies of the surface types with Chi-square (p<0.05). Results: The Maillefer was the only rulers with accuracy in all lengths and holes. Prisma presented statistically more S2 type holes when compared with other endodontic rulers evaluated (p <0.05). There was no statistically significant difference between Angelus and Maillefer (p> 0.05). Conclusion: The Maillefer presented accuracy in the millimeter and calibration portion. Angelus endodontic rulers were not accurate at any rated length of the millimeter portion and it was not accurate in most calibration holes evaluated. Prisma endodontic ruler showed significantly more calibration holes with irregular surfaces than Angelus and Maillefer. We emphasize the need for quality control and specific standards for endodontic rulers manufacturing (AU).


Subject(s)
Quality Control , Calibration , Electronics , Reference Standards , Methods
10.
J. health med. sci. (Print) ; 7(4): 231-238, oct.-dic. 2021. ilus, tab
Article in Spanish | LILACS | ID: biblio-1391707

ABSTRACT

To ensure a reliable verification of a radiation detector, the right parameters for this response verification must be determined and a specific characterization on the detectors of interest must be performed. These were the main pillars of this study, where four Geiger-Müller at the University of Costa Rica's Cyclotron Facilities' main laboratories were studied and characterized using a 137Cs source. First, a verification of the inverse-square law was performed to corroborate the correct measurement by the detectors as the distance from a 137Cs source to the detectors was varied using a new design for a positioner support to ensure repeatability. This verification yielded a potential fit curve with and equation D=670635 x-1.961 (error percentage of 1.95%) and an R2 value of 0.9836. Then, using combinations of copper plates of widths 1.0 mm and 2.0 mm as attenuators between the source and the detectors, the mass attenuation coefficient for copper was obtained only as a reference value for future calibrations of the detectors. The result for this value was 0.040 cm2 /g. The results obtained in this study and the method developed to achieve these results will serve as a base for calibrations of the detectors at these facilities, which will ensure the safety of the patients and personnel in this building.


Para asegurar respuesta correcta de un detector de radiación, se deben determinar los parámetros correctos para esta verificación y debe realizarse una caracterización específica de los detectores de interés. Estos fueron los pilares principales de este estudio, donde se estudiaron y caracterizaron 4 detectores Geiger-Müller en los laboratorios principales del Ciclotrón de la Universidad de Costa Rica utilizando una fuente radiactiva de 137Cs. Primero, se realizó una verificación de la ley del inverso-cuadrado para corroborar la medición correcta de los detectores según se varía la distancia entre la fuente de 137Cs al detector utilizando un diseño nuevo de un soporte posicionador para la fuente que asegura la repetibilidad entre experimentos. Esta verificación resultó en una curva de ajuste potencial de ecuación D=670635x-1,961 (porcentaje de error de 1,95%) y un valor de R2 de 0,9836. Luego, utilizando combinaciones de placas de cobre de espesores 1,0 mm y 2,0 mm como atenuadores entre la fuente y los detectores, se obtuvo el coeficiente de atenuación másico para el cobre como un valor de referencia para futuras calibraciones de los detectores. Este resultado fue de 0,040 cm2/g. Los resultados obtenidos en esta investigación y el método desarrollado para lograr estos resultados servirán como una base para una futura confirmación metrológica calibraciones de los detectores en estos laboratorios, lo cual colaborará con la seguridad y protección radiológica de pacientes y trabajadores en este edificio.


Subject(s)
Radiation Monitoring/instrumentation , Radiation Monitoring/methods , Radiometry/instrumentation , Radiometry/methods , Universities , Calibration , Cesium Radioisotopes , Cyclotrons , Radiation Exposure/analysis , Radiation Exposure/prevention & control , Costa Rica
11.
Rev. colomb. cardiol ; 28(5): 410-420, sep.-oct. 2021. tab, graf
Article in Spanish | LILACS, COLNAL | ID: biblio-1357207

ABSTRACT

Resumen Objetivo: Evaluar la utilidad del índice UDT-65 para la estratificación del dolor torácico en urgencias en una población colombiana en la que se sospecha enfermedad coronaria. Método: Se condujo la validación externa del índice UDT-65 en una cohorte concurrente que incluyó pacientes que ingresaron a urgencias de una clínica cardiovascular en Bogotá con dolor torácico no traumático, y electrocardiograma normal o no diagnóstico. Se evaluaron 1320 pacientes de 18 o más años y se determinó la utilidad del índice en términos de calibración (uso de gráfico, ji al cuadrado para datos agrupados y prueba de bondad de ajuste de Hosmer-Lemeshow) y de capacidad de discriminación del modelo (curva de características operativas del receptor [ROC] y área bajo ella [AUC]). Resultados: El índice UDT-65 en esta población suministró evidencia de su utilidad en términos de calibración y capacidad de discriminación, para efectuar una buena aplicación de él en aquellos pacientes que consulten al servicio de urgencias de una clínica cardiovascular por dolor torácico no traumático de posible origen coronario. La capacidad de discriminación del índice UDT-65 fue adecuada, pues con un área bajo la curva ROC de 0.867 (IC 95% 0-847-0.885), que se acerca al valor obtenido (AUC 0.87) en la población española en que se desarrolló el índice. Conclusiones: Se necesitan más estudios similares en otras instituciones, dado el buen resultado, en beneficio de más pacientes.


Abstract Objective: To evaluate the clinical usefulness, in the emergency service, of the UDT-65 index for chest pain stratification in colombian population with suspected coronary disease. Method: The external validation of the UDT-65 index was conducted in a concurrent cohort that included patients admitted to the emergency service of the cardiovascular clinic in Bogotá with non-traumatic chest pain and normal or non-diagnostic electrocardiogram. 1320 patients were evaluated and the usefulness of this instrument was determined in terms of calibration (use of graph, Chi-square test for group data and the Hosmer-Lemeshow goodness-of-fit test) and discrimination capacity of the model (curve of receiver operating characteristics [ROC] and by finding the area under the curve [AUC]). Results: The UDT-65 index in the population under study, provided evidence of its usefulness in terms of calibration and discrimination capacity; this, in pursuance of a good application of the instrument in those patients who consult the Emergency Department of the cardiovascular clinic for non-traumatic chest pain of possible coronary origin. The discrimination capacity of the UDT65 index was adequate, with an area under the ROC curve of 0.867 (95 % CI 0.847-0.885), which is close in value to the one obtained (AUC 0.87) in the Spanish population where the original index was developed. Conclusions: More similar studies are needed in other institutions, due to the excellent and beneficial outcomes.


Subject(s)
Humans , Male , Female , Middle Aged , Aged , Chest Pain/diagnosis , Coronary Disease/diagnosis , Acute Coronary Syndrome/diagnosis , Calibration , Logistic Models , Sensitivity and Specificity , Electrocardiography
12.
Rio de Janeiro; rBLH; 2 rev; set. 2021. [8] p. ilus.(Normas técnicas BLH-IFF/NT, 1, 44). (BLH-IFF/NT 44.21).
Monography in Spanish, Portuguese | LILACS, BVSAM | ID: biblio-1436547

ABSTRACT

Esta Norma Técnica tem por objetivo estabelecer as orientações necessárias para aferição e leitura dos termômetros utilizados no controle de temperatura nos Bancos de Leite Humano e Postos de Coleta de Leite Humano, visando a garantia da qualidade nestes serviços e sua certificação.


Esta Norma Técnica tiene como objetivo establecer las orientaciones necesarias para la medición y la lectura de los termómetros utilizados en el control de la temperatura en los Bancos de Leche Humana y en los Centros de Recolección de Leche Humana, con el fin de garantizar la calidad de estos servicios y su certificación.


Subject(s)
Quality Control , Temperature , Thermometers/standards , Calibration/standards , Milk Banks/standards , Milk, Human
14.
Rev. bras. med. esporte ; 27(4): 381-385, Aug. 2021. tab, graf
Article in English | LILACS | ID: biblio-1288606

ABSTRACT

ABSTRACT Background: Objective: The study of sports biomechanics in sports medicine usually requires a special image analysis system (software) to obtain 3D kinematics data. Taking the swimming project in sports medicine as an example, 3D water images in water have always been relatively complicated and difficult. As light travels in different media, it will refract and reflect. When testing underwater movements, if only a land camera or an underwater camera is used for testing, the error caused by light refraction will be larger, which will affect the accuracy of the test data even more. Methods: Taking breaststroke movement as an example, a three-dimensional measurement method based on the Kwon3D movement analysis system is introduced. This method is different from the simple underwater camera test. It is a three-dimensional test method combining a land camera and an underwater camera. Two underwater cameras and two land cameras were used to simultaneously calibrate the water and underwater space with the same calibration frame in the experiment after analyzing and verifying the accuracy of 3D reconstruction. Results: The comprehensive reconstruction error is small, and the average relative error is less than 1%. Conclusions: The application of three-dimensional image analysis technology of vision systems in sports medicine is reasonable and worth promoting. Level of evidence II; Therapeutic studies - investigation of treatment results.


RESUMO Antecedente: Objetivo: O estudo da biomecânica do esporte na medicina esportiva geralmente requer o uso de um sistema especial de análise de imagens (software) para a obtenção de dados cinemáticos 3D. Tomando o projeto de natação na medicina esportiva como exemplo, a análise de imagens 3D da água na água sempre foi um teste relativamente complicado e difícil. À medida que a luz viaja em diferentes meios, ela refratará e refletirá. Ao testar movimentos subaquáticos, se apenas uma câmera terrestre ou subaquática for usada para o teste, o erro causado pela refração da luz será maior, o que afetará a precisão dos dados de teste ainda mais. Métodos: Tomando o movimento de nado peito como exemplo, um método de medição tridimensional baseado no sistema de análise de movimento Kwon3D é introduzido. Este método é diferente do teste simples de câmera subaquática. É um método de teste tridimensional que combina uma câmera terrestre e uma câmera subaquática. No experimento, duas câmeras subaquáticas e duas câmeras terrestres foram usadas para calibrar simultaneamente a água e o espaço subaquático com o mesmo quadro de calibração. Depois de analisar e verificar a precisão da reconstrução 3D. Resultados: O erro de reconstrução abrangente é pequeno e o erro relativo médio é inferior a 1% Conclusões: A aplicação da tecnologia de análise de imagem tridimensional do sistema de visão na medicina esportiva é razoável e vale a pena promover. Nível de evidência II; Estudos terapêuticos- investigação dos resultados do tratamento.


RESUMEN Antecedente: Objetivo: El estudio de la biomecánica del deporte en la medicina deportiva generalmente requiere el uso de un sistema de análisis de imágenes especial (software) para obtener datos de cinemática 3D. Tomando como ejemplo el proyecto de natación en medicina deportiva, el análisis de imágenes de agua en 3D en el agua siempre ha sido una prueba relativamente complicada y difícil. A medida que la luz viaja en diferentes medios, se refractará y reflejará. Al probar los movimientos bajo el agua, si solo se utiliza una cámara terrestre o una cámara submarina para realizar la prueba, el error causado por la refracción de la luz será mayor, lo que afectará aún más la precisión de los datos de la prueba. Métodos: tomando como ejemplo el movimiento de la brazada, se introduce un método de medición tridimensional basado en el sistema de análisis de movimiento Kwon3D. Este método es diferente de la simple prueba de cámara subacuática. Es un método de prueba tridimensional que combina una cámara terrestre y una cámara submarina. En el experimento, se utilizaron dos cámaras submarinas y dos cámaras terrestres para calibrar simultáneamente el agua y el espacio submarino con el mismo marco de calibración. Después de analizar y verificar la precisión de la reconstrucción 3D. Resultados: el error de reconstrucción integral es pequeño y el error relativo promedio es inferior al 1%. Conclusiones: La aplicación de la tecnología de análisis de imágenes tridimensionales del sistema de visión en la medicina deportiva es razonable y vale la pena promoverla. Nivel de evidencia II; Estudios terapéuticos- investigación de los resultados del tratamiento.


Subject(s)
Humans , Swimming/physiology , Video Recording/methods , Imaging, Three-Dimensional/methods , Biomechanical Phenomena/physiology , Algorithms , Calibration , Water
15.
Int. braz. j. urol ; 47(4): 829-840, Jul.-Aug. 2021. tab, graf
Article in English | LILACS | ID: biblio-1286765

ABSTRACT

ABSTRACT Objective: The diagnosis and treatment of female urethral stricture disease (FUSD) are practiced variably due to the scarcity of data on evaluation, variable definitions, and lack of long-term surgical outcomes. FUSD is difficult to rule out solely on the basis of a successful calibration with 14F catheter. In this study, we have tried to characterize the variable clinical presentation of FUSD, the diagnostic utility of calibration, videourodynamic study(VUDS), and urethroscopy in planning surgical management. Materials and Methods: A retrospective review of records of 16 patients who underwent surgical management of FUSD was analyzed. The clinical history, examination findings, and the results of all the investigations (including uroflowmetry, VUDS findings, urethroscopy) they underwent, the procedures they had undergone, and the follow-up data were studied. Results: A total of 16 patients underwent surgical management of FUSD. 13 out of 16 patients had successful calibration with 14F catheter on the initial presentation. These 13 patients on VUDS demonstrated significant BOO and had variable stigmata of stricture on urethroscopy. The mean IPSS, flow rate, and PVR at presentation and after urethroplasty were 23.88±4.95, 7.72±4.25mL/s, 117.06±74.46mL and 3.50±3.44, 22.34±4.80mL/s, and 12.50±8.50mL, respectively. (p <0.05). The mean flow rate after endo dilation(17F) (n=12) was 11.4±2.5mL/s while after urethroplasty improved to 20.30±4.19mL/s and was statistically significant(p <0.05). Conclusions: An adept correlation between clinical assessment, urethroscopy findings, and VUDS is key in objectively identifying FUSD and planning surgical management. A good caliber of the urethra is not sufficient enough to rule out a significant obstruction due to FUSD. Early urethroplasty provides significantly better outcomes in patients who have failed dilation as a treatment.


Subject(s)
Humans , Male , Female , Urethral Stricture/surgery , Urologic Surgical Procedures, Male , Urethra/surgery , Calibration , Retrospective Studies , Treatment Outcome
16.
Rev. Asoc. Odontol. Argent ; 109(1): 28-33, ene.-abr. 2021. tab
Article in Spanish | LILACS | ID: biblio-1280923

ABSTRACT

Objetivo: Describir una experiencia de capacitación de alumnos de grado en la evaluación radiográfica de tratamientos endodónticos realizados ex vivo. Material y métodos: Participaron un docente y 13 alumnos, cada uno de los cuales evaluó radiográficamente 100 tratamientos endodónticos realizados ex vivo para determinar si estos eran correctos o incorrectos. Posteriormente, el mismo docente, en una clase teórica, presentó a los alumnos otras imágenes radiográficas a fin de calibrar qué debería considerarse correcto o incorrecto. Luego fueron proyectadas nuevamente las radiografías de los 100 casos, y los alumnos efectuaron una nueva valoración. Para cada alumno, se determinó la frecuencia de concordancia con el docente en los 100 casos, antes y después de la calibración. Se categorizó cada observación como sin cambio, positiva (precalibración sin concordancia y poscalibración con concordancia) y negativa (precalibración con concordancia y poscalibración sin concordancia). En cada caso se calcularon la frecuencia para cada categoría, la frecuencia de concordancia entre cada alumno y el docente antes y después de la calibración, y la diferencia entre frecuencias. Resultados: La frecuencia absoluta de casos con concordancia alumno/docente sin cambios fue entre 65 y 85; con cambio positivo, entre 14 y 29; y con cambio negativo, entre 1 y 8. La concordancia antes y después de la calibración resultó entre 37% y 79,2%. Conclusión: La calibración mejoró parcialmente la capacitación de los alumnos para la evaluación radiográfica de los tratamientos endodónticos (AU)


Aim: To describe one experience of calibration in the radiographic evaluation of 100 endodontic treatments performed ex vivo in undergraduate students. Material and methods: One professor and 13 undergraduate students participated in this study, who independently radiographically evaluated 100 ex vivo endodontic treatments and determined whether each case was correct or incorrect. Later, the same professor presented a theoretical class to the students with other radiographic images in order to calibrate the difference between correct and incorrect treatments. Then the radiographs of the same 100 cases were projected and the students made a new evaluation. The frequency of agreement with the teacher was determined for each student in the 100 cases before and after the calibration. Each observation was categorized as without change, with positive change (pre-calibration without agreement and post-calibration with agreement) and with negative change (pre-calibration with agreement and post-calibration without agreement). The frequency for each category was calculated for each student. In each of the cases, the frequency of students in which concordances with the teacher were observed before and after calibration, and the difference between both frequencies were calculated. Results: The absolute frequency of cases with agreement of the students/teacher without changes varied between 65 and 85, with a positive change between 14 and 29 and a negative change between 1 and 8. The concordance before and after calibration varied between 37.0% and 79.2%. Conclusion: Calibration partially improved the training of students in radiographic evaluation of endodontic treatments (AU)


Subject(s)
Humans , Male , Female , Root Canal Therapy/statistics & numerical data , Education, Predental , Educational Measurement , Argentina , Schools, Dental , Students, Dental/psychology , Calibration , Radiography, Dental/methods , Tooth, Nonvital/diagnostic imaging , Faculty, Dental
17.
China Journal of Chinese Materia Medica ; (24): 1616-1621, 2021.
Article in Chinese | WPRIM | ID: wpr-879069

ABSTRACT

Spatial distribution uniformity is the critical quality attribute(CQA) of Ginkgo Leaves Tablets, a variety of big brand traditional Chinese medicine. The evaluation of the spatial distribution uniformity of active pharmaceutical ingredients(APIs) in Ginkgo Leaves Tablets is important in ensuring their stable and controllable quality. In this study, hyperspectral imaging technology was used to construct the spatial distribution map of API concentration based on three prediction models, further to realize the visualization research on the spatial distribution uniformity of Ginkgo Leaves Tablets. The region of interest(ROI) was selected from each Ginkgo Leaves Tablet, with length and width of 50 pixels, and a total of 2 500 pixels. Each pixel had 288 spectral channels, and the number of content prediction data could reach 1×10~5 for a single sample. The results of the three models showed that the Partial Least Squares(PLS) model had the highest prediction accuracy, with calibration set determination coefficient R_(pre)~2 of 0.987, prediction set determination coefficient R_(pre)~2 of 0.942, root mean square error of calibration(RMSEC) of 0.160%, and root mean square error of prediction(RMSEP) of 0.588%. The classical least-squares(CLS) model had a greater prediction error, with the RMSEP of 0.867%. Multivariate Curve Resolution-Alternating Least Square(MCR-ALS) model showed the worst predictive ability among the three models, and it couldn't realize content prediction. Based on the prediction results of PLS and CLS models, the spatial distribution map of APIs concentration was obtained through three-dimensional data reconstruction. Furthermore, histogram method was used to evaluate the spatial distribution uniformity of API. The data showed that the spatial distribution of APIs in Ginkgo Leaves Tablets was relatively uniform. The study explored the feasibility of visualization of spatial distribution of Ginkgo Leaves Tablets based on three models. The results showed that PLS model had the highest prediction accuracy, and MCR-ALS model had the lowest prediction accuracy. The research results could provide a new strategy for the visualization method of quality control of Ginkgo Leaves Tablets.


Subject(s)
Calibration , Ginkgo biloba , Least-Squares Analysis , Medicine, Chinese Traditional , Plant Leaves , Quality Control , Spectroscopy, Near-Infrared , Tablets
18.
Journal of Biomedical Engineering ; (6): 951-959, 2021.
Article in Chinese | WPRIM | ID: wpr-921833

ABSTRACT

In order to suppress the geometrical artifacts caused by random jitter in ray source scanning, and to achieve flexible ray source scanning trajectory and meet the requirements of task-driven scanning imaging, a method of free trajectory cone-beam computed tomography (CBCT) reconstruction is proposed in this paper. This method proposed a geometric calibration method of two-dimensional plane. Based on this method, the geometric calibration phantom and the imaging object could be simultaneously imaged. Then, the geometric parameters could be obtained by online calibration method, and then combined with the geometric parameters, the alternating direction multiplier method (ADMM) was used for image iterative reconstruction. Experimental results showed that this method obtained high quality reconstruction image with high contrast and clear feature edge. The root mean square errors (RMSE) of the simulation results were rather small, and the structural similarity (SSIM) values were all above 0.99. The experimental results showed that it had lower image information entropy (IE) and higher contrast noise ratio (CNR). This method provides some practical value for CBCT to realize trajectory freedom and obtain high quality reconstructed image.


Subject(s)
Algorithms , Calibration , Cone-Beam Computed Tomography , Image Processing, Computer-Assisted , Phantoms, Imaging
19.
China Journal of Chinese Materia Medica ; (24): 5658-5664, 2021.
Article in Chinese | WPRIM | ID: wpr-921750

ABSTRACT

The calibration of chromone reference extract(CRE) was conducted and a quality control method of Saposhnikoviae Radix(SR) was established based on CRE. Meanwhile, the quality control system of SR was improved and the feasibility of using reference extract as a substitute for single reference substance in quality control of Chinese medicine was discussed. In this study, the content of the prepared CRE was calibrated with prim-O-glucosylcimifugin, cimifugin, 4'-O-β-D-glucosyl-5-O-methylvisamminol, and secO-glucosylhamaudol as indicators. Subsequently, an HPLC analytical method was developed to determine the content of four chromones in 20 batches of SR samples based on the CRE with known content as the standard substance. T-test was used for the comparison of the determination results of the two methods(single chemical component and CRE as reference substances, respectively), and the P values of prim-O-glucosylcimifugin, cimifugin, 4'-O-β-D-glucosyl-5-O-methylvisamminol, and sec-O-glucosylhamaudol were 0. 16,0. 39, 0. 14, and 0. 42. The results demonstrated that there was no significant difference between the two methods. This study initially verified the feasibility that the CRE could be used as a substitute for single reference substance in quality control of SR. In conclusion,this study is expected to provide a scientific basis and a new research model for the application of reference extract in the quality control of Chinese medicine.


Subject(s)
Apiaceae , Calibration , Chromatography, High Pressure Liquid , Chromones , Drugs, Chinese Herbal , Quality Control
20.
Acta Medica Philippina ; : 24-30, 2021.
Article in English | WPRIM | ID: wpr-959951

ABSTRACT

@#<p style="text-align: justify;"><strong>Objective.</strong> Second-generation force-controlled periodontal probes were developed to address examiner-related factors in the application of standard forces while probing. However, previous researches comparing the accuracy of first and second-generation probes have failed to yield unequivocal results. This study aimed to determine the accuracy and reproducibility of a first-generation UNC-15 probe and force-controlled Gram probe #2, used by senior and junior dental students in measuring probing pocket depths (PPD).</p><p style="text-align: justify;"><strong>Methods.</strong> Eight senior and eight junior dental students participated in the study. A periodontal model was positioned on a digital balance. Each participant performed probing four times, twice using a UNC-15 and twice employing a Gram probe #2. The order of probe usage was randomly assigned. The PPD and probing forces employed were recorded initially and after a 15-minute interval. Data were analyzed using a t-test at a 0.05 significance level.</p><p style="text-align: justify;"><strong>Results.</strong> Both junior and senior students used significantly higher probing forces (35.3 ± 1.4 and 29.9 ± 2.1 g, respectively) than the standard 25 g when using the UNC-15 probe. The junior students employed accurate forces using the Gram probe while probing both anterior (25.6 ± 1.2 g) and posterior teeth (25.1 ± 0.7 g). In comparison, the seniors used accurate forces (26.0 ± 1.3 g) only while examining anterior teeth. The PPD values obtained by both student groups were comparable to the actual PPD, except for significantly higher measurements (P=0.0003) obtained by juniors when examining posterior teeth using the Gram probe. When assessing the reproducibility of PPD measurements obtained from two examinations, values were reproducible for both juniors and seniors when using the Gram probe and during an inspection of posterior teeth using the UNC-15 probe.</p><p style="text-align: justify;"><strong>Conclusions.</strong> The Gram probe #2 had better reproducibility and yielded forces closer to the standard 25 g. However, more accurate PPD values were obtained with the UNC-15 probe.</p>


Subject(s)
Periodontal Pocket , Diagnosis , Calibration
SELECTION OF CITATIONS
SEARCH DETAIL