Local Diagnostic Reference Levels for Pediatric Interventional Cardiology Procedures in Argentina.

The aim of this work was to propose a preliminary local diagnostic reference levels (DRL) for pediatric interventional cardiology (PIC) procedures in Argentina, for different ranges of age and weight. This work has been conducted in the framework of the "Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean" (OPRIPALC) program coordinated by the World Health Organization and the Pan American Health Organization in cooperation with the International Atomic Energy Agency to ensuring that radiation exposures of pediatric patients are the minimum necessary during fluoroscopy-guided interventional procedures. The local DRL values presented in this paper by weight group and age group were 7.1 Gy·cm2 (<5 kg), 10.7 Gy·cm2 (5-15 kg), 18.0 Gy·cm2 (15-30 kg), 15.9 Gy·cm2 (30-50 kg), and 28.2 Gy·cm2 (50-80 kg) and 5.3 Gy·cm2 (<1), 11.2 Gy·cm2 (1 to 5<), 19.6 Gy·cm2 (5 to 10<), and 21.4 Gy·cm2 (10 to 16<), respectively. Our dose results are among the values found in other international studies; however, there is great potential for dose optimization.

Optimization of Radiation Protection in Pediatric Interventional Radiology in Latin America and the Caribbean: Development, Advancements, Challenges and Achievements of the OPRIPALC Program.

This article presents the development, advancements, challenges and achievements of the "Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean" (OPRIPALC) program. This international initiative is led by the World Health Organization, the Pan American Health Organization and the International Atomic Energy Agency. The main objectives of OPRIPALC are to foster a culture of radiological protection in pediatric interventions, enhance these procedures' quality, and define optimization strategies such as the use of diagnostic reference levels (DRLs). Currently, 33 centers from 12 countries participate actively in the program. Significant progress has been made towards the proposed objectives, overcoming the challenges posed by the COVID-19 pandemic. Through many virtual meetings for coordination, planning, training and follow-up, a comprehensive set of DRLs for both diagnostic and therapeutic procedures, categorized by weight and age, have been established and are in use. A consensus document on good practices is in the final stage of development. The program's continuation into at least a second phase is essential to address pending issues, including the integration of automatic dose management systems, the levels of occupational radiation doses, their correlation with pediatric patient doses, and strategies to reduce them.

Establishing national clinical diagnostic reference levels and achievable doses for CT examinations in Brazil: A prospective study.

PURPOSE: Diagnostic reference levels (DRL) and achievable doses (AD) are important tools for radiation dose optimization. Therefore, a prospective study was performed which aimed to establish a multi-parametric, clinical indication based - DRL(DRLCI) and clinical indication - AD (ADCI) for adult CT in Brazil. METHODS: The prospective study included 4787 patients (50 ± 18 years old; male:female 2041:2746) at 13 Brazilian sites that have been submitted to head, paranasal sinus, cervical spine, chest, or abdomen-pelvis CT between January and October 2021 for 13 clinical indications. The sites provided the following information: patient age, gender, weight, height, body mass index[BMI], clinical indications, scanner information(vendor, model, detector configuration), scan parameters (number of scan phases, kV, mA, pitch) and dose-related quantities (CT dose index volume- CTDIvol, dose length product- DLP). Median(AD) and 75th(DRL) percentile CTDIvol and DLP values were estimated for each body region and clinical indications. Non-normal data were analyzed with the Kruskal-Wallis test. RESULTS: In majority of Brazilian sites, body region and clinical indications based DRLs were at or lower than the corresponding DRLs in the US and higher than Europe. Although radiation doses varied significantly for patients in different body mass index groups (p < 0.001), within each body region, there were no differences in radiation doses for different clinical indications (p > 0.1). Radiation doses for 7/13 clinical indications were higher using iterative reconstruction technique than for the filtered back projection. CONCLUSIONS: There was substantial variation in Brazil DRLCI across different institutions with higher doses compared to the European standards. There was also a lack of clinical indication-based protocol and dose optimization based on different clinical indications for the same body region.

Niveles de referencia para diagnóstico según PUBMED: ¿es suficiente la información disponible? / Diagnostic reference levels according to PUBMED: is the information available sufficient?

RESUMEN Los Niveles de Referencia para Diagnóstico (NRD) son una herramienta dinámica que gana cada vez una mayor importancia para la optimización de las exposiciones médicas. La disponibilidad de información científica es esencial en este proceso de optimización para Medicina Nuclear (MN) y Radiología Diagnóstica (RD). Este trabajo presenta un estudio de la disponibilidad de información sobre los NRD para MN y RD en la base PubMed, en los últimos 20 años, empleando diferentes palabras clave. Se analizó de forma crítica la información disponible, buscando los cambios principales que se han producido como tendencia en diferentes aspectos del establecimiento de los NRD. Se verificó un desbalance significativo en la disponibilidad de literatura científica en estas dos áreas, aunque se ha incrementado la información para equipos híbridos y de forma general para todas las tecnologías. Este desbalance se hace mayor para estudios de medicina nuclear en pediatría. Se observaron avances en la forma de recolectar datos, la manera de organizar la información y analizarla, en especial con la disponibilidad de sistemas de monitoreo de dosis. Se encontró que, en los estudios TC e intervencionismo, las agrupaciones por localización anatómica están siendo acotadas o restringidas, por indicaciones clínicas que tienen similitudes en los requisitos de calidad de imagen para el diagnóstico adecuado. Similarmente en MN se vislumbra la incorporación de la actividad por peso como NRD en las tecnologías híbridas y estudios pediátricos. Este estudio demuestra que, en general, la literatura científica disponible sobre los NRD es mucho más amplia para pacientes adultos. Se requiere más estudios pediátricos, especialmente en el área de MN

ABSTRACT Diagnostic Reference Levels (DRLs) are a dynamic tool that is gaining more and more importance for the optimization of medical exposures. The availability of scientific information is essential in this optimization process for Nuclear Medicine (NM) and Diagnostic Radiology (DR). This work presents a revision of the information's availability about DRL in the PubMed database, in the last 20 years, using different search combinations. The available information was critically analyzed, looking for the main changes that have occurred as a trend in different aspects of the establishment of the NRD. A significant disparity in the amount of information between the two areas on the subject was verified, although there has been an increase of available scientific papers for hybrid equipment, and in general for all technologies. The disparity becomes greater for NM studies in pediatrics population. The way to collect data, the mode to organize the information and analyze it, has also undergone changes, mainly with radiation dose management systems. In CT and interventional studies, the grouping by anatomical locations is being constrained or modulated by clinical indications with analogous image quality requirements for proper diagnosis. Something similar happens in MN, where the incorporation of activity/patient's weight is envisioned as NRD for hybrid technologies and pediatric studies. In general, the study showed that, the scientific paper's availability about DRL for adult population are much wider. More pediatric studies on these subjects are needed, especially in NM

Urinary levels of 30 metal/metalloids in the Brazilian southeast population: Findings from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

The assessment of risks associated with environmental exposure to metals/metalloids requires well-established reference values for each population since it varies considerably according to distinct local/regional characteristics. However, very few studies establish baseline values for these elements (essential and toxic) in large population groups, especially in Latin American countries. This study was aimed at establishing urinary reference levels of 30 metals/metalloids: aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), cadmium (Cd), cerium (Ce), cesium (Cs), chromium (Cr), cobalt (Co), copper (Cu), lanthanum (La), lead (Pb), lithium (Li), strontium (Sr), manganese (Mn), mercury (Hg), molybdenum (Mo), nickel (Ni), platinum (Pt), rubidium (Rb), selenium (Se), silver (Ag), tin (Sn), tellurium (Te), thallium (Tl), thorium (Th), tungsten (W), uranium (U) and zinc (Zn) in a Brazilian southeast adult population. This pilot study is a cross-sectional analysis conducted with the first wave of the ELSA-Brasil cohort (baseline examination). A total of 996 adults (45.5% men, N = 453, mean age: 50.5, and 54.5% women, N = 543, mean age: 50.6) were included in the study. Sample analyses were performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Percentiles (2.5, 10, 25, 50, 75, 95 (CI95%), and 97.5) of each element (µg/g of creatinine) in the study are presented according to sex. Moreover, differences in the mean metal/metalloid urinary levels according to age, education, smoking, and alcohol intake are also presented. Finally, median found values were compared to established values of large human biomonitoring surveys previously conducted in North America and France. This is the first comprehensive and systematic human biomonitoring study that established population reference ranges for 30 (essential and/or toxic elements) in a Brazilian population group.

Attributable patient risk in nuclear medicine procedures and establishment of diagnostic reference levels.

The assessment of risk related to medical exposures as a justification tool to assist decision-making of the medical team is not available in clinical routine. The determination of diagnostic reference levels (DRLs) for nuclear medicine (NM) procedures has been proposed as an optimization tool, but this tool has still been aimed at a standard adult individual. It is known that the activity administered, and the consequent absorbed doses in critical organs, represents the risk of a procedure being cancer induction the greatest concern, especially for young patients. Thus, the adjustment of administered activity and procedure risk to promote risk-benefit assessment is a promising tool for routine clinical use. This work aims to present a tool for determining DRLs in the administered activity related to the patient's characteristics-age group, sex, and body mass index (BMI), in order to assist the medical decision regarding the risk-benefit ratio. Thus, it is possible to assess the risk of carcinogenesis in groups of patients, considering absorbed doses in organs, cancer incidence, and mortality rates in our country. NIREA is an IT tool developed in PHP language for web environment as a friendly software. It allows the establishment of DRL and risk of cancer induced by radiation assessment through the estimation of absorbed doses in specific organs and based on the risk methodology of BEIR VII. The absorbed and effective doses were estimated based on the dose conversion factors of the radiopharmaceuticals published by the International Commission on Radiological Protection adjusted for the patient groups. Based on data from 2256 patients who underwent diagnostic procedures at National Cancer Institute between 2017 and 2019, the program was used, resulting in important information for conducting the clinical routine extracted as DRL, absorbed doses, and risk assessments, considering patient-specific data such as age, sex, and BMI. The methodology developed in this work allows NM services to keep their data available and updated regarding local DRLs, in addition to allowing the nuclear physician to know the risk of each procedure performed, extracted by individual characteristics of the patient. The affirmative is significant because the data could be used by the regulatory body of practices with ionizing radiation in Brazil to establish a reference level in Activity that has not yet existed in the country.

Setting up regional diagnostic reference levels for pediatric interventional cardiology in Latin America and the Caribbean countries: preliminary results and identified challenges.

The goal of the present study was to propose a set of preliminary regional diagnostic reference levels (DRLs) for pediatric interventional cardiology (IC) procedures in Latin America and the Caribbean countries, classified by age and weight groups. The study was conducted in the framework of the Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean program coordinated by the World Health Organization and the Pan American Health Organization in cooperation with the International Atomic Energy Agency. The first step of the program was focused on pediatric IC. Dose data from diagnostic and therapeutic procedures were collected between December 2020 and December 2021. Regional DRLs were set as the third quartile of patient dose data (kerma area product) collected in 18 hospitals from 10 countries in an initial sample of 968 procedures. DRLs were set for four age bands and five weight ranges. The values obtained for the four age bands (<1 yr, 1 to <5 yr, 5 to <10 yr and 10 to <16 yr) were 2.9, 6.1, 8.8 and 14.4 Gy cm2for diagnostic procedures, and 4.0, 5.0, 10.0 and 38.1 Gy cm2for therapeutic procedures, respectively. The values obtained for the five weight bands (<5 kg, 5 to <15 kg, 15 to <30 kg, 30 to <50 kg and 50 to <80 kg) were 3.0, 4.5, 8.1, 9.2 and 26.8 Gy cm2for diagnostic procedures and 3.7, 4,3, 7.3, 16.1 and 53.4 Gy cm2for therapeutic procedures, respectively. While initial data were collected manually as patient dose management systems (DMSs) were not available in most of the hospitals involved in the program, a centralized automatic DMS for the collection and management of patient dose indicators has now been introduced and is envisaged to increase the sample size. The possibility of alerting on high dose values and introducing corrective actions will help in optimization.

Diagnostic Reference Levels for Common X-ray Procedures in Peru.

Diagnostic reference levels (DRLs) for X-ray procedures have been established in many countries since 1996. In Peru, data from the literature are used as guidelines as DRLs research is limited. The objective of this study is to analyze the parameters and variables which are used in radiological techniques such as kV, mAs, and type of machine (conventional or digital); study the geographical distribution of radiological X-ray machines, and establish DRLs in Peru. Two radiological procedures were considered, general X-rays (fixed and mobile) and intraoral X-rays (fixed, mobile, and portable). An Unfors RaySafe Xi detector (Unfors RaySafe AB, Billdal, Sweden) was used; air kerma was measured at a source to image distance that varied depending on the procedure, and the entrance skin dose was subsequently calculated using the Arcal XLIX formalism. The data were collected over a period of three years (2015-2017). Only results from the last evaluation during this period were taken into consideration for each X-ray machine. DRLs were calculated at 0.21 mSv, and 0.25 mSv for posterior-anterior chest examinations in conventional and digital machines, respectively; 4.39 mSv and 6.01 mSv for conventional and digital antero-posterior lumbar spine examinations, respectively; and at 4.21 mSv for the dental intraoral procedure. The largest amount of X-ray machines is concentrated in the city of Lima. These results reflect the standard of practice in Peru.

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

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

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

Niveles de Referencia para Diagnóstico Locales en Procedimientos Radiográficos Dentales Periapicales. Primeros valores para Chile / Local Diagnostic Reference Levels for Periapical Radiographs. First Values for Chile

La información que aportan los procedimientos de radiología dental, tanto en la evaluación, como en el diagnóstico y tratamiento de patologías y/o alteraciones dento maxilofaciales, hace que correspondan al tipo más frecuente de estudio radiológico. Sin embargo, existe un escaso conocimiento en nuestro país respecto de los niveles de dosis que se imparten en dichos procedimientos, haciendo necesaria su determinación para maximizar el beneficio derivado de los mismos y minimizar el riesgo radiológico para los pacientes. El presente estudio determinó el nivel de referencia para diagnóstico (NRD) local en la radiografía periapical de Molar maxilar e Incisivo, para ello se realizaron simulaciones de los procedimientos radiográficos en un maniquí antropomorfo seccional y se determinó el valor de Kerma aire en la superficie de entrada con retrodispersión mediante dosimetría termoluminiscente. Los NRD locales determinados en la radiografía periapical de Molar maxilar fueron 5,6 mGy para adultos y 4,0 mGy para niños; mientras que en la radiografía periapical de Incisivo fue de 9,2 mGy para pacientes adultos y 1,8 mGy para niños. Los resultados obtenidos buscan orientar la ejecución de futuras investigaciones en el área y aportar información del nivel de radiación en estos procedimientos, con lo que se espera promover una cultura de radioprotección y motivar la optimización de las dosis registradas.

The information provided by dental radiology procedures, both in evaluation, as well as in the diagnosis and treatment of pathologies and / or dentomaxilofacial alterations, makes them the most frequent type of radiological study. However, there is a meager knowledge in our country regarding dose levels applied in such procedures, making their determination necessary to maximize the benefits and to minimize the radiological risk to patients. The present study determined the local diagnostic reference level (LDRL) for the periapical radiography of the Maxillary molar and Incisive. Simulations of radiographic procedures were performed and the value of air Kerma at the entrance surface with backscattering, was estimated using thermo luminescent dosimetry. The LDRL determined in the maxillary molar periapical radiography was 5.6 mGy for adults and 4.0 mGy for children; while on the incisive periapical radiography it was 9.2 mGy for adult patients and 1.8 mGy for children. The results obtained seek to guide the execution of future research in the area and provide information on the radiation doses delivered in these procedures, which is expected to promote a radiation protection culture and motivate the optimization of the registered doses.

Niveles de referencia de dosis para adultos en procedimientos de cardiología intervencionista en Ecuador. / Reference even of dose for adults in procedures of cardiology interventionist in Ecuador

Antecedents and objective: The knowledge of the reference levels for diagnoses and therapeutic studies is important, because it contributes to the optimization of the radiological protection of the patients, avoiding them to be exposed to unnecessarily high doses. However, there was no evidence of these levels in interventionist cardiology procedures in Ecuador, so the objective of this study was to estimate the diagnostic reference levels of dose at the entrance surface in adult patients undergoing interventional cardiology procedures (cinecoronariography, catheterization and coronary percutaneous interventionism) in the Unit of Hemodynamic of the Hospital of Specialties Carlos Andrade Marín in Ecuador. Materials and methods: The measurements of product dose-area, dose in input surface, number of images and the time of fluoroscopy performed using the Axiom Artis angiographer, and the obtained data was tabulated and processed with the Excel computer program. For this study, 145 patients older than 18 years were selected, and the values obtained from diagnostic reference dose levels were compared with others reported in previous investigations and with the permissible limits for the appearance of deterministic effects on the skin. Results: This study made it possible to establish reference levels for diagnosis in interventional cardiology procedures (coronary angiography, catheterization and percutaneous coronary intervention) in the Hemodynamics Unit of the Carlos Andrade Marín Specialty Hospital in Ecuador. Conclusions: The results showed that the intake surface doses obtained were lower than the maximum levels recommended by the International Atomic Energy Agency.

Antecedentes y objetivo: El conocimiento de los niveles de referencia para estudios diagnósticos y terapéuticos es importante, dado que contribuye a la optimización de la protección radiológica de los pacientes y evita que se expongan a dosis innecesariamente altas; sin embargo, no se encontraron evidencias de estos niveles en procedimientos de cardiología intervencionista en Ecuador, por lo cual el objetivo de este estudio fue calcular los niveles de referencia diagnósticos de dosis en la superficie de entrada en pacientes adultos sometidos a procedimientos intervencionistas de cardiología (cinecoronariografía, cateterismo e intervencionismo percutáneo coronario) en la Unidad de Hemodinámica del Hospital de Especialidades Carlos Andrade Marín de Ecuador. Materiales y métodos: Las mediciones del producto dosis-área, dosis en superficie de entrada, número de imágenes y tiempo de fluoroscopia se realizaron con el angiógrafo Axiom Artis y los datos obtenidos se tabularon y procesaron con el programa informático Excel. Para este estudio se seleccionó a 145 pacientes mayores de 18 años y los valores obtenidos de niveles de referencia diagnósticos de dosis se compararon con otros informados en investigaciones anteriores y con los límites permisibles para la aparición de efectos deterministas en piel. Resultados: Este estudio permitió establecer los niveles de referencia para diagnóstico en los procedimientos intervencionistas de cardiología (cinecoronariografía, cateterismo e intervencionismo percutáneo coronario) en la Unidad de Hemodinámica del Hospital de Especialidades Carlos Andrade Marín de Ecuador. Conclusiones: Los resultados mostraron que las dosis en superficie de entrada obtenidas fueron menores a los niveles máximos recomendados por la International Atomic Energy Agency.

Niveles de Referencia para Diagnóstico en Procedimientos Radiológicos Dentales: Una Guía Práctica / Diagnostic Reference Levels in Dental Radiological Procedures: A Practical Guide

RESUMEN: Las exposiciones médicas con radiación ionizante son actualmente la principal fuente de exposición a la radiación artificial a nivel global, entre ellas, los exámenes dentales corresponden a uno de los más frecuentes. Para prevenir dosis innecesariamente altas a los pacientes durante estas exposiciones, la Comisión Internacional de Protección Radiológica (ICRP) recomienda la utilización de Niveles de Referencia para Diagnóstico (DRLs), como una herramienta efectiva de ayuda a la optimización de la protección radiológica en la exposición médica de pacientes. Dado que la legislación de Chile aún no ha incorporado el uso de los DRLs, el presente trabajo de revisión tuvo como objetivo analizar la publicación N° 135 de la ICRP para generar un documento que sirva de guía para los odontólogos, explicando de manera didáctica y en un lenguaje sencillo, pero técnico, los principales aspectos a tener en cuenta para establecer los DRLs en procedimientos de radiología dental.

SUMMARY: Currently exposure to ionizing radiation is currently the main source of exposure to artificial radiation worldwide, with dental examinations being one of the most frequent events. In order to prevent exposure of unnecessarily high doses in patients, the International Commission on Radiological Protection (ICRP) recommends the use of Diagnostic Reference Levels (DRLs), as an effective tool to help maximize protection from radiation during medical exposure of patients. Given that the Chilean legislation has not yet incorporated the use of DRLs, the purpose of this study was to analyze publication N° 135 of the ICRP to generate a document, to serve as a guide for dentists, didactically outlining in simple but technical language, the main aspects to consider when establishing DRLs in dental radiology procedures.

Valores típicos de dosis para tomografía computada de cerebro en pacientes adultos / Typical dose values for brain computed tomography in adult patients

Resumen: Debido al aumento en el uso de la Tomografía Computada (TC), y en consecuencia, la probabilidad de generar un incremento progresivo de la dosis recibida por los paciente y su relación en el potencial riesgo de los efectos de las radiaciones ionizantes, es importante implementar el uso de niveles de referencia diagnóstico (DRLs) en TC, como herramienta fundamental dentro de un programa de control de calidad que permita la evaluación y optimización de las dosis entregadas a los pacientes según la tarea clínica deseada. Con el objetivo de establecer valores típicos de dosis en TC de cerebro en Clínica Bupa Reñaca, se estudió una muestra de 73 informes dosimétricos generados en un equipo TC Toshiba Aquilion 64, en términos de indicadores de dosis para TC: Índice de dosis en TC por volumen (CTDIvol) y Producto dosis longitud (DLP). Con los datos obtenidos, se estimó el valor del percentil 50 (p50) para cada indicador de dosis, y se determinaron los valores típicos de dosis en cada grupo estudiado según sexo, edad e indicación clínica. Se logró definir y establecer una metodología que permitió la obtención de los valores típicos de dosis para TC de cerebro, optimizando las dosis sin producir una disminución en la calidad de la imagen necesaria para nuestro propósito clínico.

Abstract: Due to the increase in the use of Computed Tomography (CT), and consequently, the probability of generating a progressive increase in the dose received by the patient and its relationship in the potential risk of the effects of ionizing radiation, it is important to implement the use of diagnostic reference levels (DRLs) in CT, as a fundamental tool within a quality control program that allows the evaluation and optimization of the doses delivered to patients according to the desired clinical task. In order to establish typical dose values in brain CT at Bupa Reñaca Clinic, a sample of 73 dosimetric reports generated on a Toshiba Aquilion 64 CT unit was studied, in terms of dose indicators for CT: Dose rate on CT by volume (CTDIvol) and Dose Length Product (DLP). With the data obtained, the value of the 50th percentile (p50) for each dose indicator was estimated, and typical dose values were determined in each group studied according to sex, age and clinical indication. It was possible to define and establish a methodology that allowed obtaining typical dose values for brain CT, optimizing the doses without producing a decrease in the image quality necessary for our clinical purpose.

Xpektrin, un simulador de espectros fácil de usar y ampliamente distribuible para radiología general / Xpektrin, an easy to use and highly distributable X-Ray spectra simulator in general radiography

Resumen: Se presenta una aplicación basada en Microsoft Excel llamada Xpektrin para el cálculo de dosis en radiología general. La aplicación permite simular espectros de rayos X en radiología general utilizando el modelo TASMICS a partir de mediciones del kerma en aire (Kair) y de la capa Hemirreductora (HVL). Tiene implementado el cálculo de magnitudes radiométricas y dosimétricas, como el kerma en aire en la superficie de entrada (Ke) y la dosis en piel (Dskin), en función de la elección arbitraria de los factores de exposición, el tipo y grosor de filtro, la distancia foco-piel y el tamaño de campo. Xpektrin fue validado con la herramienta computacional SPEKTR 3.0, utilizando mediciones de dosis y de HVL de tubos de rayos X de tres recintos hospitalarios. Se encontró buena correlación en ambas aplicaciones entre las mediciones experimentales y los valores calculados de HVL y con coeficientes de Pearson R² ≥ 0.99 en todos los casos. Sin embargo, se obtuvo mejor concordancia con los valores experimentales de HVL con Xpektrin (mediana de diferencias -0.43%, -0.04% y 0.01%) que con SPEKTR 3.0 (mediana de diferencias -3.31%, 0.10% y -7.85%), en particular para el tubo con mayor filtración. Xpektrin está optimizada para ser utilizada en los departamentos de radiología para la determinación de dosis de pacientes individuales en función de los parámetros utilizados durante la exposición, por lo que puede ser utilizada como parte de un sistema de registro dosimétrico o como apoyo para el establecimiento de niveles de referencia para diagnóstico (NRD), siendo particularmente útil en servicios con equipos sin registros automáticos de dosis. Además, debido a sus características de simulador, puede ser útil como herramienta pedagógica. El uso de Excel permite que sea altamente distribuible y fácil de usar, sin necesidad de conocimientos de programación.

Abstract: Xpektrin, an easy to use and highly distributable X-Ray Spectra Simulator in General Radiography. An application based on Microsoft Excel called Xpektrin is presented for dose calculation in general radiology. The application was developed to simulate X-ray spectra in general radiography using the TASMICS model. Using as inputs air kerma (Kair) and Half-value layer (HVL) measurements, Xpektrin allows the calculation of several radiometric and dosimetric quantities, such as the entrance surface air kerma (Ke) and the skin dose (Dskin), depending on the exposure factors, filter material type, filter thickness, focus-skin distance and field size. Xpektrin was validated against the Matlab toolkit SPEKTR 3.0, using dose and HVL measurements of X-ray tubes from three different hospitals. It was found good correlation in both applications between the experimental measurements and the calculated HVL and Kair values with Pearson coefficients R² ≥ 0.99 in all cases. However, experimental and calculated HVL have better agreement with Xpektrin (median percent difference -0.43%, -0.04% and 0.01%) than SPEKTR 3.0 (median percent difference -3.31%, 0.10% and -7.85%), particularly for the tube with greater filtration thickness. Xpektrin is optimized to be used in radiology departments for patient dose determination depending on the exposure parameters and may be used as part of a dosimetric record system or as a support for the determination of Diagnostic Reference Levels, which may be useful when no automatic dose records are available. In addition, due to its simulator characteristics, it can be useful as a pedagogical tool. Using Excel allows Xpektrin to be highly distributable and easy to use, without the need for programming skills.

Niveles de referencia para diagnóstico: una herramienta efectiva para la protección radiológica de pacientes / Diagnostic reference levels: an effective tool to radiological protection of patient

Se sabe que las exposiciones médicas con radiaciones ionizantes son actualmente la principal fuente de exposición a la radiación artificial a nivel global. Para prevenir dosis innecesariamente altas durante estas exposiciones a los pacientes, la Comisión Internacional de Protección Radiológica (ICRP) recomienda la utilización de los Niveles de Referencia para Diagnóstico (DRLs), como una herramienta efectiva de ayuda a la optimización de la protección radiológica en la exposición médica de pacientes para diagnóstico y procedimientos de intervención. Dado que la legislación chilena no tiene incorporado aún su uso, el presente trabajo de revisión tiene como objetivo, elaborar un documento guía para los profesionales de la salud y áreas afines, que contenga de manera sucinta y con recomendaciones prácticas, los principales aspectos a tener en cuenta para establecer los DRLs en procedimientos de radiodiagnóstico, intervencionismo y medicina nuclear, basados esencialmente en la publicación N° 135 de la ICRP sobre DRLs.

It is known that medical exposition with ionizing radiation is currently the main exposition source to artificial radiation at global level. To prevent unnecessarily high doses during these patient expositions, the International Commission on Radiological Protection (ICRP) recommends the use of Diagnostic Reference Levels (DRLs), as an effective tool to support the optimization of radiological protection for patient medical exposure for diagnosis and interventional procedures. Since that the Chilean legislation does not have its use incorporated yet, the present revision work aims to elaborate a guiding document for health professionals and related fields, that succinctly and with practical recommendations, the main aspects to consider for establishing DRLs in procedures for radiodiagnostic, intervention, and nuclear medicine, mainly based in N° 135 ICRP publication about DRLs.

Local patient dose diagnostic reference levels in pediatric interventional cardiology in Chile using age bands and patient weight values.

PURPOSE: To present the results of a patient dose evaluation program in pediatric cardiology and propose local diagnostic reference levels (DRLs) for different types of procedure and age range, in addition to suggesting approaches to correlate patient dose values with patient weight. This study was the first conducted in Latin America for pediatric interventional cardiology under the auspices of the International Atomic Energy Agency. METHODS: Over three years, the following data regarding demographic and patient dose values were collected: age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time (FT), and two dosimetric quantities, dose-area product (DAP) and cumulative dose (CD), at the patient entrance reference point. The third quartile values for FT, DAP, CD, number of cine series, and the DAP/body weight ratio were proposed as the set of quantities to use as local DRLs. RESULTS: Five hundred and seventeen patients were divided into four age groups. Sample sizes by age group were 120 for <1 yr; 213 for 1 to <5 yr; 82 for 5 to <10 yr; and 102 for 10 to <16 yr. The third quartile values obtained for DAP by diagnostic and therapeutic procedures and age range were 1.17 and 1.11 Gy cm2 for <1 yr; 1.74 and 1.90 Gy cm2 for 1 to <5 yr; 2.83 and 3.22 Gy cm2 for 5 to <10 yr; and 7.34 and 8.68 Gy cm2 for 10 to <16 yr, respectively. The third quartile value obtained for the DAP/body weight ratio for the full sample of procedures was 0.17 (Gy cm2 /kg) for diagnostic and therapeutic procedures. CONCLUSIONS: The data presented in this paper are an initial attempt at establishing local DRLs in pediatric interventional cardiology, from a large sample of procedures for the standard age bands used in Europe, complemented with the values of the ratio between DAP and patient weight. This permits a rough estimate of DRLs for different patient weights and the refining of these values for the age bands when there may be large differences in child size. These DRLs were obtained at the largest pediatric hospital in Chile, with an active optimization program, and could be used by other hospitals in the Latin America region to compare their current patient dose values and determine whether corrective action is appropriate.

Disminución de la dosis de radiación en el radiodiagnóstico / Reducing the dose of radiation in diagnostic radiology

El número de procedimientos radiológicos ha tenido un incremento acelerado durante la primera década del siglo XXI, obteniendo un impacto beneficioso sobre la salud. Sin embargo, este incremento conlleva a una mayor exposición a las radiaciones ionizantes. El uso de la radiación ionizante tiene un riesgo inherente, aun cuando el riesgo asociado a un examen radiológico es menor comparado con el riesgo natural, cualquier riesgo añadido, no importa cuán pequeño sea, es inaceptable si no se beneficia el paciente. El concepto de niveles de referencia diagnósticos se debe utilizar para reducir las variaciones en la práctica entre las instituciones y promover rangos óptimos, indicadores de dosis para los protocolos específicos de las diferentes modalidades. En general, los principios básicos de la protección radiológica (justificación, optimización y límite de dosis) deben ser respetados para ayudar a contrarrestar el incremento injustificado en el número de procedimientos que se realizan.

The number of radiological procedures performed has had a rapid increase during the first decade of the 21st century, achieving a beneficial impact on healthcare. However, this increase leads to a greater exposure to ionizing radiation. The use of ionizing radiation has an inherent risk. Although the risk associated with a radiological examination is minor compared to the natural risk, any added risk, no matter how small, is unacceptable if it does not benefit the patient. The concept of diagnostic reference levels should be used to reduce variations in practice among institutions and to promote optimal dose indicator ranges for specific protocols of the different methods. In general, the basic principles of radiation protection (justification, optimization and dose limits) must be followed to reduce the unjustified increase in the number of procedures being performed.

Avaliação do kerma no ar na superfície de entrada e da qualidade da imagem em radiografias de tórax / Evaluation of entrance surface air kerma rate and clinical images quality in chest radiography

OBJETIVO: Avaliar os fatores de técnica utilizados durante exames de tórax póstero-anterior em pacientes-padrão e correlacioná-los aos valores de kerma no ar na superfície de entrada e à qualidade das imagens clínicas. MATERIAIS E MÉTODOS: O estudo foi realizado em três hospitais do Rio de Janeiro, num total de cinco salas de raios X, com dez pacientes por sala. As imagens foram avaliadas pelos radiologistas dos serviços segundo o protocolo europeu. O kerma no ar na superfície de entrada foi estimado a partir da curva de rendimento do equipamento de raios X, que foi obtida utilizando câmara de ionização acoplada a um eletrômetro. Análise de variância foi realizada para verificar se a diferença entre os valores de kerma no ar na superfície de entrada é significativa. RESULTADOS: Os valores de kerma no ar na superfície de entrada variaram entre 0,05 e 0,26 mGy, com média 60 por cento inferior ao nível de referência publicado na Portaria 453. Das imagens avaliadas, 98 por cento atenderam acima de 65 por cento dos critérios de qualidade. CONCLUSÃO: Para um padrão de qualidade da imagem, aceitável para o diagnóstico, verificou-se ampla variação do kerma no ar na superfície de entrada para pacientes-padrão. Isto demonstra a falta de padronização dos fatores de técnica e a existência de um potencial de redução do valor do kerma no ar na superfície de entrada.

OBJECTIVE: To evaluate technical factors involved in posteroanterior chest radiography in standard patients, and correlating them with entrance surface air kerma rate and with the clinical images quality. MATERIALS AND METHODS: The present study was developed at three hospitals in Rio de Janeiro, Brazil, involving a total of five x-ray rooms, with ten patients per room. The images were evaluated by the radiologists of the institutions, in accordance with the European protocol. The estimation of surface entrance air kerma rate was based on the x-ray equipment output curve obtained with an ionization chamber coupled with an electrometer. Variance analysis was performed to evaluate the significance of the difference between entrance surface air kerma rates. RESULTS: Entrance surface air kerma rates ranged between 0.05 and 0.26 mGy, with a mean value 60 percent lower than the reference level established by the Order (Portaria) 453. Among the images evaluated, 98 percent fulfilled > 65 percent of the images quality criteria. CONCLUSION: For a standard image quality that is acceptable for diagnosis purposes, a significant variation was observed in the entrance surface air kerma rate for standard patients, demonstrating the lack of technical factors standardization and a potential for decreasing the entrance surface air kerma rate.