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PURPOSE: This interlaboratory comparison was conducted to evaluate the performance of the Latin-American Biodosimetry Network (LBDNet) in analyzing digitized images for scoring dicentric chromosomes from in vitro irradiated blood samples. The exercise also assessed the use of weighted robust algorithms to compensate the uneven expertise among the participating laboratories. METHODS: Three sets of coded images obtained through the dicentric chromosome assay from blood samples irradiated at 1.5 Gy (sample A) and 4 Gy (sample B), as well as a non-irradiated whole blood sample (sample C), were shared among LBDNet laboratories. The images were captured using the Metafer4 platform coupled with the AutoCapt module. The laboratories were requested to perform triage scoring, conventional scoring, and dose estimation. The dose estimation was carried out using either their laboratory calibration curve or a common calibration curve. A comparative statistical analysis was conducted using a weighted robust Hampel algorithm and z score to compensate for uneven expertise in dicentric analysis and dose assessment among all laboratories. RESULTS: Out of twelve laboratories, one had unsatisfactory estimated doses at 0 Gy, and two had unsatisfactory estimated doses at 1.5 Gy when using their own calibration curve and triage scoring mode. However, all doses were satisfactory at 4 Gy. Six laboratories had estimated doses within 95% uncertainty limits at 0 Gy, seven at 1.5 Gy, and four at 4 Gy. While the mean dose for sample C was significantly biased using robust algorithms, applying weights to compensate for the laboratory's analysis expertise reduced the bias by half. The bias from delivered doses was only notable for sample C. Using the common calibration curve for dose estimation reduced the standard deviation (s*) estimated by robust methods for all three samples. CONCLUSIONS: The results underscore the significance of performing interlaboratory comparison exercises that involve digitized and electronically transmitted images, even when analyzing non-irradiated samples. In situations where the participating laboratories possess different levels of proficiency, it may prove essential to employ weighted robust algorithms to achieve precise outcomes.

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Purpose: This paper describes how the BioDoseNet image repository was used as a training tool for the dicentric assay.Materials and methods: The training was implemented in three phases: introduction to dicentric scoring, dose response curve elaboration and dose assessment exercise. Four labs without previous experience in the dicentric assay participated and four modules of the repository were used.Results: The labs become familiar with aberrations induced by ionizing radiation. The labs were able to generate data for the elaboration of a dose response curve and then successfully estimated doses and irradiated fractions in six blind samples.Conclusions: The performance of these laboratories during the exercise demonstrates the efficacy of the BioDoseNet image repository as a training tool and the utility of web based scoring for the dicentric assay community.

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Introducción: la Estimulación Magnética Transcraneal (EMT) es una técnica neurofsiológica, que permite la inducción de una corriente en el cerebro de forma segura y no invasiva. Está basada en los principios de inducción electromagnética descubiertos por el investigador Michael Faraday hace dos siglos. Recién en 1984, Anthony Barker y su equipo de trabajo desarrollaron un estimulador que permitía despolarizar neuronas en la corteza motora y provocar movimientos contralaterales al activar vías corticoespinales, a partir de lo cual se ha logrado su aplicación en clínica psiquiátrica para diferentes trastornos. La EMTr puede utilizarse como complemento de otros métodos neurocientífcos en el estudio de vías motoras centrales, para el estudio de la excitabilidad cortical y en el mapeo de funciones cerebrales corticales, pudiendo combinar la capacidad de resolución temporal y espacial y la potencialidad de activar o interferir en funciones cerebrales. Materiales y métodos: los pacientes fueron seleccionados de acuerdo al diagnóstico bajo la patología F 33 ­ F 51 por el personal del servicio y remitidos a la unidad de Estimulación Magnética Transcraneal. Se les realizó exámenes complementarios como: TAC de cráneo, electroencefalograma, valoración psicológica pre y post EMTr, dentro de un protocolo estrictamente aplicado, sin el cual no se decide proceder a este tratamiento. Resultados: en el presente estudio no se hizo diferenciaciones entre el tipo de depresión y tampoco en lo relacionado a los trastornos del ritmo del sueño. Se encontró satisfacción en la mayoría de pacientes, sometidos a este tratamiento y muchos mejoraron su depresión y calidad de sueño con la estimulación repetitiva, proponiéndose como una nueva opción de tratamiento no farmacológico ni psicoterapéutico; además es accesible a todo tipo de población, siempre y cuando se cuenta con la infraestructura tecnológica para este procedimiento.

ABSTRACT Introduction: transcranial magnetic stimulation (TMS) is a neurophysiological technique that allows electric currents induction into the brain in a safe and noninvasive way. TMS is based on electromagnetic induction discovered by Faraday two centuries ago. Only in 1984, Anthony Barker and his team developed a stimulator that allowed depolarization of neurons in the motor cortex causing contralateral movements by activating corticospinal pathways, from which it has achieved its application on different conditions in psychiatric clinic. TMS can be used with other neuroscientifc methods to combine the ability of temporal and spatial resolution and the potentiality to activate or interfere brain functions when studying central motor pathways, cortical excitability and brain cortical function mapping. Materials and methods: for the study, patients were selected under pathology F33 and F51, diagnosed by medical service personnel and sent to the Magnetic Stimulation Unit. Additional tests such as head CT, EEG, psychological evaluation pre and post rTMS (repetitive TMS) were performed within a strict protocol. If some of the tests could not be carried out, the treatment did not proceed. Results: in this study, differences on type of depression or sleep rhythm disorders were not made. Our results showed that satisfaction was found in the majority of patients undergoing this treatment and many of them even improved with repetitive stimulation their depression and sleep quality, thus, proposing an alternate non-pharmacological or psychotherapeutic treatment. Besides, it is accessible to most people, as long as the technological infrastructure for this procedure is set up.

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