Correction of INRAPORC® prediction errors for a commercial pig system / Correção de erros de predição do INRAPORC ® para um sistema comercial de suínos

ABSTRACT: INRAPORC® is a mechanistic, dynamic, and deterministic model system that is used in commercial pig production. However, its use is limited as it requires performance information for animals under ad libitum (AL) feed management, which is not provided at all stages of production. Verification of the INRAPORC® calibrations were conducted in this investigation using data from a small group of animals fed with AL in a laboratory situation, to simulate the mean kinetics of a larger commercial population and generate the correction equations for the predicted body weight (BW), and backfat thickness (BT). Analyses were performed by comparing the predicted and observed data, and by submitting them to prediction calibration curve tests (b0 = 0, and b1 = 1). The obtained curves presented a systematic, fixed effect error (+2.37 mm) for BT. The predicted BW and BT values were corrected using the values of the systematic errors obtained. As a result, 100% of the BW averages observed were contained in the confidence intervals (CI) of the INRAPORC® predicted averages, without the need for corrections, and 78.5% of the actual BT averages were contained in the CI of the averages predicted by the system, after corrections. The INRAPORC® calibrations, based on a small population of animals in laboratory conditions could thus be utilized to make predictions for commercial pig production systems and for value correction procedures for the BW and BT of pig populations that have systematic errors in their prediction validations.

RESUMO: O INRAPORC® é um sistema de modelos mecanicista, dinâmico e determinista. Seu uso em sistemas comerciais de produção de suínos é restrito, pois necessita de informações de desempenho de animais sob manejo alimentar à vontade (AV), uma vez que este manejo não é utilizado em todas as fases de produção. Por isso é interessante verificar se a calibração do INRAPORC® baseada em um pequeno grupo de animais AV em situação laboratorial é capaz de simular a cinética média de uma população comercial maior e de subsidiar equações de correção de dados preditos de peso vivo (PV) e espessura de toucinho (ET). As análises foram realizadas comparando os dados preditos e observados sob o teste da curva de calibração da predição (b0=0 e b1=1), as curvas obtidas apresentaram erro sistemático de efeito fixo para a ET de +2,37mm. Os valores preditos de PV e ET foram corrigidos utilizando os valores dos erros sistemáticos obtidos. Como resultado, 100% das médias observadas de PV, estavam contidas nos intervalos de confiança (IC) das médias preditas pelo INRAPORC®, sem necessidade de correções e 78,5% das médias reais de ET estavam contidas nos IC das médias preditas pelo sistema, após as correções. A calibração do INRAPORC® baseada em uma pequena população de animais em situação laboratorial pode ser aplicada para predições de um sistema comercial de criação de suínos, bem como a aplicação do procedimento de correção dos dados preditos de PV e ET nas populações suínas que apresentem erros sistemáticos nas validações preditivas do sistema.

Tolerance and dosimetric study of multi-leaf collimator leaf position accuracy for dynamic intensity-modulated radiotherapy / 中华放射肿瘤学杂志

Objective:To evaluate the dosimetric effect of multi-leaf collimator (MLC) position error on dynamic intensity-modulated radiotherapy (dMLC-IMRT), aiming to provide guidance for the establishment of MLC quality control accuracy and operation tolerance.Methods:In the phantom study, the virtual water phantom established in the treatment planning system (TPS), and three dynamic sliding window test fields with gap width of 5 mm, 10 mm and 20 mm were designed. Clinical treatment plans of 7 common tumor types were extracted, including nasopharyngeal carcinoma, glioma, lung cancer, esophageal cancer, cervical cancer, prostate cancer, and breast cancer, with 6 cases in each. MLC errors were introduced into the copy from original plan to generate the simulation plans. MLC errors included systematic open/close error, systematic deviation error and random error. The dosimetric differences between the original and simulation plans were compared.Results:The phantom study showed that the symbol of dose deviation was the same as that of systematic open/close error, and the value was increased with the increase of MLC error and decreased with the increase of gap width. The results of patient study showed that the systematic open/close error had a significant effect on dosimetry, the target volume dose sensitivities of different plans were 7.258-13.743%/mm, and were negatively correlated with the average field width. The dosimetric deviation caused by the systematic shift error below 2 mm was less than 2%. The dosimetric change caused by the random error below 2 mm could be neglected in clinical treatment.Conclusions:The minimal gap width should be limited in TPS, whereas the quality control of MLC should be strengthened. In addition, for the dynamic intensity-modulated treatment technology, 2 mm random error was suggested to be the operation tolerance during treatment delivery, and 0.2 mm alignment accuracy on each side (or 0.4 mm unilateral) is recommended to be the MLC quality control accuracy to ensure the dose accuracy of radiotherapy for different tumors.

Analysis of utility of optical surface imaging system for patients who received radiotherapy with active breath control / 中华放射肿瘤学杂志

Objective To analyze the precision and stability of optical surface imaging system for patients who received radiotherapy with active breath control. Methods Eighteen radiotherapy patients with lung metastasis were managed by active breath control (ABC).The difference error detected by optical surface imaging system and CBCT were defined as the precision of optical surface imaging system. The variation among the error of optical surface imaging positioning the value of correction of treatment position and the error detected by optical surface imaging again were defined as the stability of optical surface imaging system. Intrafractional errors were analyzed by optical surface imaging system through whole treatment process (including breath hold and free breath). Results The optical surface imaging system had precision (systematic (Σ) and random errors (σ)) of 1.78/3.42 mm 2.54/6.57 mm and 2.79/3.22 mm respectively and stability of2.12/2.54 mm 3. 09/4.02 mm and 1.37/3.55 mm respectively in lateral-medial superior-inferior and anterior-posterior directions. The intrafractional errors (Σ and σ) were 0.42/0.85 mm 0.41/1.47 mm and 0.41/1.47 mm respectively for breath hold duration and 4.76/4.16 mm 6.54/7.78 mm and 3.13/5.92 mm for free breath duration in lateral-medial superior-inferior and anterior-posterior directions. Conclusions As an effective method for validate breath hold;Optical surface imaging system can improve the precision and safety of active breath control. However,the factors that affect the accuracy and stability of the optical surface imaging system in patients undergoing radiotherapy with ABC are not clear;it cannot replace the CBCT for positioning verification.

Evaluación de los límites analíticos de desempeño del laboratorio del HIGA O. Alende de Mar del Plata / Evaluation of analytical limits of performance in the laboratory of HIGA O. Alende of Mar del Plata / Avaliação dos limites analíticos de desempeno do laboratório do HIGA O. Alende de Mar del Plata

Los límites analíticos de desempeño (LAD) forman parte del diseño del programa de control de calidad analítico. Los objetivos de este trabajo fueron determinar imprecisión (CV), error sistemático (ES) y error total (ET) de 14 analitos de Química Clínica en los sectores de planta y de guardia del laboratorio del HIGA O. Alende de Mar del Plata, evaluar su desempeño analítico según variabilidad biológica y comparar los datos obtenidos. Se realizó un estudio retrospectivo con el registro de controles de calidad y se utilizaron los LAD derivados de VB para obtener las especificaciones de calidad para CV, ES y ET. Respecto del CV, cumple con los criterios el 79% en el sector planta y el 64% en el de guardia. Y en cuanto al ET, cumple el 90% y el 75%, respectivamente. En conclusión, aunque la mayoría de los analitos evaluados cumplen al menos con los criterios mínimos establecidos, los resultados ponen de manifiesto la necesidad de mejorar el desempeño analítico. Detectar los tipos de errores presentes en el proceso de laboratorio es el primer paso para instaurar controles de procedimiento y análisis, soluciones que permitirán mejorar la calidad analítica, uno de los pilares que optimizan la seguridad del paciente.

The analytical limits of performance (ALP) are part of the programme design of analytical quality control. The goals of this study were to determine imprecision (VC), systematic error (SE) and total error (TE) of 14 clinical chemistry analytes in the routine and emergency laboratory of HIGA O. Alende of Mar del Plata, to evaluate their analytical performance in accordance with biological variability, and compare the data obtained. A retrospective study was performed using the record of quality controls. The ALP were obtained from BV to get the quality specifications for VC, SE and TE. Regarding VC, 78% of the analytes meet the criteria in the routine laboratory and 64% in the emergency. Regarding TE, in the routine laboratory, 90% meet the TE criteria, and 75% in the emergency. It can be concluded that, although most of the evaluated analytes meet at least the minimum established criteria, the results highlight the need to improve the analytical performance. Detecting the types of errors in the laboratory process is the first step to establish procedural and analysis controls. These are solutions that will improve the analytical quality, one of the pillars to optimize patient safety.

Os limites analíticos de desmpeño (LAD) são parte do desenho do programa de controle de qualidade analítico. Os objetivos deste estudo foram determinar a imprecisão (CV), o erro sistemático (ES) e o erro total (ET) de 14 analitos de Química Clínica nas áreas de planta e de plantão do laboratório HIGA O. Alende de Mar del Plata, avaliar seu desempenho analítico de acordo com a variabilidade biológica e comparar os dados obtidos. Um estudo retrospectivo foi realizado com o registro de controles de qualidade utilizando os LAD derivados de VB para obter as especificações de qualidade para CV, ES e ET. Quanto ao CV, 79% cumpre com os critérios no setor da planta e 64% no setor de plantão. E, quanto ao ET, cumpre 90% e 75% respectivamente. Em conclusão, embora a maioria dos analitos testados cumpra pelo menos com os critérios mínimos estabelecidos, os resultados destacam a necessidade de melhorar o desempenho analítico. Detectar os tipos de erros encontrados no processo de laboratório é o primeiro passo para estabelecer controles de procedimento e análise, soluções que permitirão melhorar a qualidade analítica, um dos pilares que otimizam a segurança do paciente.

Trueness Controls of Clinical Laboratory to Assess Bias / 现代检验医学杂志

Precision controls monitor assay random error (reproducibility),accuracy controls assess total error,both random error and systematic error,and trueness (bias)of an assay represents systematic error.A trueness control should be metro-logical traceable,ideally with a target value determined by use of a reference material or a reference method,without metro-logical traceable to a reference measurement system,patient test results for the same patient from different laboratories may not be comparable.A trueness control should be commutable and its analytical response to a reference method and a routine field method should be equivalent to that of a patient sample.And trueness control values should generally be set at medical decision levels and be prepared by the providers of reference materials and manufactured in the same fashion as a calibrator.

Veracidad de un analizador de gasometria para determinar glucemia, respecto a un metodo de laboratorio convencional / Reliability of a gas analyzer to determine glycemia compared to the conventional laboratory method

Objetivos:Determinar el grado de veracidad en los resultados de glucosa, medidos en un equipo de gasometría, mediante lacomparación con un procedimiento de uso habitual en el laboratorio, siguiendo el procedimiento indicado en la guía EP9–A2 delClinical and Laboratory Standards Institute(CLSI).Diseño:Estudio descriptivo con muestreo no probabilístico.Institución:HospitalEdgardo Rebagliati Martins, EsSalud, Lima, Perú.Material:Muestra sanguínea de 234 sujetos provenientes de los servicios deemergencia y la unidad de cuidados intensivos.Métodos:Se procesó glucemia en los equipos ADVIA1800 y el gasómetro ABL800.Se comparó los resultados de ambos analizadores siguiendo las directrices de la mencionada guía, además del análisis gráfico deBland-Altman y el cálculo del coeficiente de concordancia correlación (CCC) de Lin.Principales medidas de resultados:Concentraciónde glucosa sérica.Resultados:La media de glucemia obtenida fue 1,6 mg/dL mayor para ABL800 que para el ADVIA1800. Los dosmétodos de medida seguían una relación lineal, obteniéndose un coeficiente de correlación de 0,9995, con un intervalo de confianza(IC) al 95% de 0,9994a 0,9996. Los resultados de glucosa del método de estudio fueron aceptables según los requerimientos decalidad, lo cual se confirmó con los análisis estadísticos de Bland-Altman y el valor del CCCL de 0,9995, con un IC de 95% de 0,9993a 0,9996.Conclusiones:El analizador ABL800 resultó adecuado para la monitorización de glucemia; presentó una buena asociaciónlineal y veraz, cuando fue comparado con el método de referencia del laboratorio.

Objectives: To determine the glucose reliability results measured in a gas equipment as compared with a reference method commonly used in the laboratory. The Clinical and Laboratory Standards Institute (CLSI) guide EP9- A2 instructions were followed. Design: Descriptive study with non-probability sampling. Setting: Hospital Edgardo Rebagliati Martins, EsSalud, Lima, Peru. Materials: Blood sample of 234 subjects from the emergency services and intensive care unit. Methods: Blood glucose was processed with the ADVIA1800 equipment and the ABL800 gasometer. Results of both analyzers were compared following the mentioned guide directives, the Bland-Altman plot analysis and the Lin’s concordance correlation coefficient (CCC) calculation. Main outcome measures: Serum glucose concentration. Results: Average blood glucose levels obtained were 1.6 mg/dL higher for ABL800 than for ADVIA1800. Both methods showed a high positive correlation (beta coefficient 0.9995 and 95 per cent, 95 per cent CI 0.9994 to 0.9996). Glucose results for the method studied were acceptable, as confirmed with the Bland-Altman statistical analysis (0.9995 CCC value, 95 per cent CI 0.9993 to 0.9996). Conclusions: The ABL800 analyzer is suitable for blood glucose monitoring, presenting an excellent correlation with the reference laboratory method.