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1.
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
2.
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
3.
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
4.
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
5.
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
7.
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
8.
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
9.
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
10.
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
11.
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
12.
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
13.
Yonsei Medical Journal ; : 154-160, 2020.
Article in English | WPRIM | ID: wpr-782196

ABSTRACT

0.05). The area under the receiver operating characteristics curve (AUC) was 0.922 [95% confidence interval (CI) 0.89–0.95]. In external validation, the discrimination was good, with an AUC value of 0.833 (95% CI 0.70–0.92) for this model. Nomogram calibration plots indicated good agreement between the predicted and observed outcomes, exhibiting close approximation between the predicted and observed probability.CONCLUSION: We constructed a scoring model for predicting massive transfusion during cesarean section in women with placenta previa. This model may help in determining the need to prepare an appropriate amount of blood products and the optimal timing of blood transfusion.


Subject(s)
Area Under Curve , Blood Transfusion , Calibration , Cesarean Section , Cohort Studies , Discrimination, Psychological , Early Intervention, Educational , Erythrocytes , Female , Humans , Logistic Models , Maternal Age , Nomograms , Placenta Previa , Placenta , Placentation , Postpartum Hemorrhage , Pregnancy , ROC Curve , Ultrasonography
14.
Article in Chinese | WPRIM | ID: wpr-828899

ABSTRACT

To explore a method for calculating water equivalent diameter () based on localizer CT images for calculation of the size specific dose estimates (SSDE).GE Revolution CT and LightSpeed VCT were used to scan CT dose index phantoms 16 cm and 32 cm in diameter at the tube voltages of 80, 100 and 120 kV to obtain the axial image and anteroposterior localizer radiograph. According to the definition of CT Hounsfield unit, the axial images were used to calculate the conversion factors that convert the phantom thickness to water equivalent thickness. The gray value of the localizer radiograph and the water equivalent thickness were calibrated with a linear equation, and the parameters of the calibration were used to calculate the water equivalent thickness. The method was verified using 2 CT dose index phantoms and in 22 patients undergoing chest and abdominal CT examination.Comparison of the water equivalent diameter () based on the localizer radiograph and axial image of the 2 phantoms showed that the percentage difference between from the axial images and from the localizer radiograph was below 3%. The trend of variations with location in the two methods was sonsistent. The difference in in intermediate region of interest between the axial image and the localizer radiograph from the 22 patients was below 6.6%. With the mean in the ROI, the maximum percentage difference was 7.5%.Calibration of the gray value of the localizer radiograph and the water equivalent thickness using the axial image and localizer radiograph of CT dose index phantoms allows quick calculation of the SSDE based on the parameters of calibration.


Subject(s)
Calibration , Humans , Phantoms, Imaging , Radiation Dosage , Tomography, X-Ray Computed , Water
15.
Article in Chinese | WPRIM | ID: wpr-827973

ABSTRACT

A rapid analysis method based on ultraviolet-visual(UV-Vis) spectroscopy, near infrared(NIR) spectroscopy and multivariable data analysis was established for quality evaluation of Shengxuebao Mixture. The contents of eight active ingredients of Shengxuebao Mixture including albiflorin, paeoniflorin, 2, 3, 5, 4'-tetra-hydroxy-stilbene-2-O-β-D-glucopyranoside, specnuezhenide,ecliptasaponin D, emodin, calycosin-7-glucoside and astragaloside Ⅳ were simultaneously detected by using this method. HPLC-UV-MS was used as a reference method for determining the contents of these ingredients. Partial least squares(PLS) analysis was implemented as a linear method for multivariate models calibrated between UV spectrum/NIR spectrum and contents of 8 ingredients. Finally, the performance of the model was evaluated by 24 batches of test samples. The results showed that both UV-Vis and NIR models gave a good calibration ability with an R~2 value above 0.9, and the prediction ability was also satisfactory, with an R~2 value higher than 0.83 for UV-Vis model and higher than 0.79 for NIR model. The overall results demonstrate that the established method is accurate, robust and fast, therefore, it can be used for rapid quality evaluation of Shengxuebao Mixture.


Subject(s)
Calibration , Chromatography, High Pressure Liquid , Drugs, Chinese Herbal , Least-Squares Analysis , Mass Spectrometry , Spectroscopy, Near-Infrared
16.
Article in Chinese | WPRIM | ID: wpr-942045

ABSTRACT

OBJECTIVE@#To establish a high performance liquid chromatography (HPLC) method for the determination of ultraviolet (UV) absorbers UV-327 and UV-328 in mouse plasma.@*METHODS@#N-hexane-acetone (volume ratio 1 ∶1) was added to a mouse plasma sample as the extraction solvent for vortex extraction, and the supernatant was dried at 50 ℃ with nitrogen. Thereafter the residue was redissolved with methanol, centrifuged and filtered. The separation was performed on a Waters SymmetryC18 column (250 mm×4.6 mm, 5 μm), and the concentrations of UV-327 and UV-328 in the mouse plasma were determined by HPLC with an UV detector. The elution was isocratic at a flow rate of 1.0 mL/min with a mobile phase composed of 100% methanol, and the UV detection wavelength was 340 nm. The retention time was used for qualitative analysis, and the internal standard method was used for quantitative analysis using UV-320 as the internal standard.@*RESULTS@#The calibration curves of UV-327 and UV-328 were linear with correlation coefficients of 0.999 7 over the concentration range of 0.05 to 10.0 mg/L. The limit of detection was 0.01 mg/L, and the limit of quantitation was 0.03 mg/L. The average recoveries at low, medium and high three concentrations (0.50, 1.00, 2.00 mg/L) in the mouse plasma were 91.7%-101.0% for UV-327, and 97.5%-103.9% for UV-328. The intra-day precisions (n=6) of UV-327 were 2.9%-6.6%, and 2.7%-7.4% for UV-328. The inter-day precisions (n=3) of UV-327 were 6.0%-9.3%, and 6.6%-8.6% for UV-328. The extraction recoveries of UV-327 were 98.8%-103.8%, and 99.8%-100.9% for UV-328. The measured relative deviations of UV-327 in the mouse plasma samples placed at room temperature for 6 hours and -40 ℃ for 15 days were 0.9%-3.5% and 7.4%-15.0%, and the measured relative deviations of UV-328 were 2.0%-4.3% and 2.1%-13.8%, respectively. The mouse plasma samples could be stored at room temperature for 6 hours at least and -40 ℃ for 15 days at three spiked concentration levels.@*CONCLUSION@#The method was simple and fast with high accuracy, precision and sensitivity, and could be applied to the determination of UV-327 and UV-328 in mouse plasma.


Subject(s)
Animals , Calibration , Chromatography, High Pressure Liquid , Mice , Plasma , Reproducibility of Results , Ultraviolet Rays
17.
Article in Chinese | WPRIM | ID: wpr-879211

ABSTRACT

Patient-specific volumetric modulated arc therapy (VMAT) quality assurance (QA) process is an important component of the implementation process of clinical radiotherapy. The tolerance limit and action limit of discrepancies between the calculated dose and the delivered radiation dose are the key parts of the VMAT QA processes as recognized by the AAPM TG-218 report, however, there is no unified standard for these two values among radiotherapy centers. In this study, based on the operational recommendations given in the AAPM TG-218 report, treatment site-specific tolerance limits and action limits of gamma pass rate in VMAT QA processes when using ArcCHECK for dose verification were established by statistical process control (SPC) methodology. The tolerance limit and action limit were calculated based on the first 25 in-control VMAT QA for each site. The individual control charts were drawn to continuously monitor the VMAT QA process with 287 VMAT plans and analyze the causes of VMAT QA out of control. The tolerance limits for brain, head and neck, abdomen and pelvic VMAT QA processes were 94.56%, 94.68%, 94.34%, and 92.97%, respectively, and the action limits were 93.82%, 92.54%, 93.23%, and 90.29%, respectively. Except for pelvic, the tolerance limits for the brain, head and neck, and abdomen were close to the universal tolerance limit of TG-218 (95%), and the action limits for all sites were higher than the universal action limit of TG-218 (90%). The out-of-control VMAT QAs were detected by the individual control chart, including one case of head and neck, two of the abdomen and two of the pelvic site. Four of them were affected by the setup error, and one was affected by the calibration of ArcCHECK. The results show that the SPC methodology can effectively monitor the IMRT/VMAT QA processes. Setting treatment site-specific tolerance limits is helpful to investigate the cause of out-of-control VMAT QA.


Subject(s)
Calibration , Humans , Quality Assurance, Health Care , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted , Radiotherapy, Intensity-Modulated
18.
Article in Chinese | WPRIM | ID: wpr-879208

ABSTRACT

In order to conduct surface monitoring of the three-dimensional spine morphology of the human body in daily life, a spine morphology measuring method using "single camera, multi-view" to construct stereo vision is proposed. The images of the back of the human body with landmarks of spinous process are captured from multiple angles by moving a single camera, and based on the "Zhang Zhengyou calibration method" and the triangulation principle of binocular stereo vision, the spatial conversion matrices corresponding to each other between all images and the 3D coordinates of the landmarks are calculated. Then the spine evaluation angle used to evaluate the spine morphology is further calculated. The tests' results showed that the spine evaluation angle error of this method is within ±3°, and the correlation between the results and the X-ray film Cobb angles is 0.871. The visual detection algorithm used in this paper is non-radioactive, and because only one camera is used in the measurement process and there is no need to pre-set the camera's shooting pose, the operation is simple. The research results of this article can be used in a mobile phone-based intelligent detection system, which will be suitable for the group survey of scoliosis in communities, schools, families and other occasions, as well as for the long-term follow-up of confirmed patients. This will provide a reference for doctors to diagnose the condition, predict the development trend of the condition, and formulate treatment plans.


Subject(s)
Algorithms , Calibration , Humans , Imaging, Three-Dimensional , Scoliosis/diagnostic imaging , Spine/diagnostic imaging , Technology
19.
Medicina (B.Aires) ; 79(6): 438-444, dic. 2019. ilus, graf, tab
Article in English | LILACS | ID: biblio-1056751

ABSTRACT

Cardiovascular disease (CVD) is the leading cause of death in Argentina. Computer simulation models allow to extrapolate evidence to broader populations than the originally studied, over longer timeframes, and to compare different subpopulations. The Cardiovascular Disease Policy Model (CVDPM) is a computer simulation state transition model used to represent and project future CVD mortality and morbidity in the population 35 years-old and older. The objective of this study was to update Argentina’s version of the CVDPM. For this purpose, information from the 2010 National Census, the 2013 National Risk Factor Survey, CESCAS I study, and PrEViSTA study were used to update the dynamics of population size, demographics, and CVD risk factor distributions over time. Model projections were later calibrated by comparing them to actual data on CVD events and mortality in the year 2010 (baseline year) in Argentina. Country statistics for people 35 years-old and older reported for 2010 a total of 41 219 myocardial infarctions (MIs), 58 658 strokes, and 281 710 total deaths. The CVDPM, in turn, predicted 41 265 MIs (difference: 0.11%), 58 584 strokes (difference: 0.13%), and 280 707 total deaths (difference: 0.36%) in the same population. In all cases, the final version of the model predicted the actual number of events with an accuracy superior to 99.5%, and could be used to forecast the changes in CVD incidence and mortality after the implementation of public policies.


La enfermedad cardiovascular (ECV) es la principal causa de muerte en Argentina. Los modelos de simulació;n por computadora permiten extrapolar evidencia a poblaciones más amplias que las originalmente estudiadas, a lo largo de períodos prolongados, y comparar diferentes subpoblaciones. El Cardiovascular Disease Policy Model (CVDPM, por sus siglas en ingló;©s) es un modelo de simulació;n utilizado para representar y proyectar la mortalidad y morbilidad por ECV en la població;n de 35 o más aó;±os. El objetivo de este trabajo fue actualizar la versió;n argentina del CVDPM. Para esto, se utilizó; informació;n del Censo Nacional 2010, la Encuesta Nacional de Factores de Riesgo 2013, el estudio CESCAS I, y el estudio PrEViSTA, para actualizar la dinámica del tamaó;±o de la població;n, sus características demográficas, y la distribució;n de factores de riesgo cardiovasculares a lo largo del tiempo. Las proyecciones del modelo se calibraron comparándolas con informació;n sobre eventos de ECV y mortalidad en el aó;±o 2010 (aó;±o de referencia) en Argentina. Las estadísticas argentinas informaron que en 2010 la població;n de 35 o más aó;±os sufrió; un total de 41 219 infartos de miocardio (IM), 58 658 accidentes cerebrovasculares y 281 710 muertes totales. El CVDPM predijo 41 265 IM (diferencia: 0.11%), 58 584 accidentes cerebrovasculares (diferencia: 0.13%) y 280 707 muertes totales (diferencia: 0.36%). En todos los casos, la versió;n final del modelo predijo el nó;ºmero real de eventos cardiovasculares con una precisió;n superior al 99.5%, pudiendo ser utilizado para pronosticar cambios en la incidencia y mortalidad de ECV debidos de la implementació;n de políticas pó;ºblicas.


Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , Aged, 80 and over , Computer Simulation , Cardiovascular Diseases/mortality , Mortality/trends , Risk Assessment/methods , Argentina/epidemiology , Time Factors , Calibration , Sex Factors , Incidence , Reproducibility of Results , Risk Factors , Age Factors , Sex Distribution , Age Distribution , Forecasting
20.
Medicina (B.Aires) ; 79(6): 438-444, dic. 2019. ilus, graf, tab
Article in Spanish | LILACS | ID: biblio-1056750

ABSTRACT

La enfermedad cardiovascular (ECV) es la principal causa de muerte en Argentina. Los modelos de simulació;n por computadora permiten extrapolar evidencia a poblaciones más amplias que las originalmente estudiadas, a lo largo de períodos prolongados, y comparar diferentes subpoblaciones. El Cardiovascular Disease Policy Model (CVDPM, por sus siglas en ingló;©s) es un modelo de simulació;n utilizado para representar y proyectar la mortalidad y morbilidad por ECV en la població;n de 35 o más aó;±os. El objetivo de este trabajo fue actualizar la versió;n argentina del CVDPM. Para esto, se utilizó; informació;n del Censo Nacional 2010, la Encuesta Nacional de Factores de Riesgo 2013, el estudio CESCAS I, y el estudio PrEViSTA, para actualizar la dinámica del tamaó;±o de la població;n, sus características demográficas, y la distribució;n de factores de riesgo cardiovasculares a lo largo del tiempo. Las proyecciones del modelo se calibraron comparándolas con informació;n sobre eventos de ECV y mortalidad en el aó;±o 2010 (aó;±o de referencia) en Argentina. Las estadísticas argentinas informaron que en 2010 la població;n de 35 o más aó;±os sufrió; un total de 41 219 infartos de miocardio (IM), 58 658 accidentes cerebrovasculares y 281 710 muertes totales. El CVDPM predijo 41 265 IM (diferencia: 0.11%), 58 584 accidentes cerebrovasculares (diferencia: 0.13%) y 280 707 muertes totales (diferencia: 0.36%). En todos los casos, la versió;n final del modelo predijo el nó;ºmero real de eventos cardiovasculares con una precisió;n superior al 99.5%, pudiendo ser utilizado para pronosticar cambios en la incidencia y mortalidad de ECV debidos de la implementació;n de políticas pó;ºblicas.


Cardiovascular disease (CVD) is the leading cause of death in Argentina. Computer simulation models allow to extrapolate evidence to broader populations than the originally studied, over longer timeframes, and to compare different subpopulations. The Cardiovascular Disease Policy Model (CVDPM) is a computer simulation state transition model used to represent and project future CVD mortality and morbidity in the population 35 years-old and older. The objective of this study was to update Argentina’s version of the CVDPM. For this purpose, information from the 2010 National Census, the 2013 National Risk Factor Survey, CESCAS I study, and PrEViSTA study were used to update the dynamics of population size, demographics, and CVD risk factor distributions over time. Model projections were later calibrated by comparing them to actual data on CVD events and mortality in the year 2010 (baseline year) in Argentina. Country statistics for people 35 years-old and older reported for 2010 a total of 41 219 myocardial infarctions (MIs), 58 658 strokes, and 281 710 total deaths. The CVDPM, in turn, predicted 41 265 MIs (difference: 0.11%), 58 584 strokes (difference: 0.13%), and 280 707 total deaths (difference: 0.36%) in the same population. In all cases, the final version of the model predicted the actual number of events with an accuracy superior to 99.5%, and could be used to forecast the changes in CVD incidence and mortality after the implementation of public policies.


Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , Aged, 80 and over , Computer Simulation , Cardiovascular Diseases/mortality , Mortality/trends , Risk Assessment/methods , Argentina/epidemiology , Time Factors , Calibration , Sex Factors , Incidence , Reproducibility of Results , Risk Factors , Age Factors , Sex Distribution , Age Distribution , Forecasting
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