Characterization of Geiger-Müller radiation detectors response at the University of Costa Rica's Cyclotron Facilities / Caracterización de la respuesta de detectores de radiación Geiger-Müller en el Ciclotrón de la Universidad de Costa Rica

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.

¿Son reproducibles las mediciones dosimétricas a bajas dosis en cardiología intervencionista? / Are dosimetric measurements at low doses reproducible in interventional cardiology?

Abstract. There are several methods for measuring the absorbed radiation dose of occupationally exposed professionals, but it is unknown if these are reproducible at low doses. The aim of this study is to determine the level of reproducibility of thermoluminescent dosimeters (TLD) and optically stimulated luminescence dosimeters (OSL) in simulated conditions. A reproducibility study was performed using two types of dosimeters, which were placed in the location of medical interventionist work area inside the catheter laboratory. An anthropomorphic phantom was used as a patient and the same projections, collimation and radiographic techniques that were employed in the past 30 angiographies, an examination considered as low exposure in the context of interventional cardiology. Lin's concordance coefficient correlation was calculated, obtaining a value of -0.006 with a 95% CI of -0.069 to 0.056 for TLD dosimeters with OSL. The data obtained showed poor reproducibility at low doses of radiation.

Resumen. Existen varios métodos para medir la dosis de radiación absorbida por los profesionales ocupacionalmente expuestos, pero se desconoce si estos son reproducibles entre sí a bajas dosis. El objetivo del estudio fue determinar el grado de reproducibilidad entre los dosímetros termoluminiscentes (TLD) y los dosímetros luminiscentes ópticamente estimulados (OSL), en condiciones simuladas. Se realizó un estudio de reproducibilidad, empleando 2 tipos de dosímetros, los cuales se dispusieron en la ubicación de trabajo del médico intervencionista dentro del pabellón. Se empleó un fantoma antropomórfico como paciente y se replicaron las mismas proyecciones, colimación y técnicas radiológicas empleadas en las últimas 30 coronariografías, examen considerado de baja exposición en el contexto de cardiología intervencionista. Se aplicó el coeficiente de correlación de concordancia de Lin, obteniéndose un valor de -0,006 con un IC al 95% de -0,069 a 0,056 para los dosímetros TLD con OSL. Los datos obtenidos mostraron una escasa reproducibilidad a bajas dosis de radiación.

[Evaluation of the natural gamma radiation level in residential zones and determination of annual effective exposure dose in the residents of Hamadan province, Iran, 2012]

Human is always exposed to natural background ionizing radiation which may have harmful effects; therefore, measurement of the natural background radiation is important. In this study, was measured the dose of effective natural background gamma radiation in indoor residential zones of Hamadan Province. In this cross-sectional study, we selected four stations along the main geographic directions and one in the center of city for measurement of the indoor dose rate in each of the cities in Hamadan Province. Based on the household numbers, some houses were selected randomly in every station and natural background indoor dose was measured by using RDS-110 survey meter. Then, using the results of our previous study about measuring the level of outdoor natural gamma radiation in this province, we determined the level of annual effective exposure dose from natural gamma radiation in Hamadan residents. In Hamadan province cities, maximum and minimum indoor natural background radiation [gamma ray] belonged to Razan City [1.41 +/- 0.079 mSv] and Asadabad City [0.955 +/- 0.044 mSv], respectively. Mean annual equivalent indoor dose in Hamadan Province was 1.20 +/- 0.070 mSv. Also the maximum indoor natural background radiation dose [gamma ray] in the buildings with the age of more and less than 25 years were 1.42 +/- 0.219 mSv and 1.44 +/- 0.149 mSv, respectively. According to the results of this study and our previous study about outdoor gamma natural background radiation, the annual effective dose in Hamadan Province residents was 0.83 mSv. According to the results of this study, it seems that annual effective equivalent dose due to indoor gamma radiation in Hamadan Province exceeded the mean external exposure amount reported by UNSCEAR [0.5 mSv]. Also the annual effective dose due to gamma background radiation in Hamadan Province residents is 0.83 mSv, which is higher than the global average [0.48 mSv] reported by UNSCEAR - 2000. Therefore epidemiological studies to assess the prevalence of chronic diseases associated with natural radiation exposure among Hamadan Province residents are recommended

Occupational Hazard: Radiation Exposure for the Urologist – Developing a Reference Standard

Introduction To date, there is a paucity of literature offering practicing urologists a reference for the amount of radiation exposure received while surgically managing urolithiasis. This study examines the cumulative radiation exposure of an urologist over 9 months. Materials and Methods We present a case series of fluoroscopic exposures of an experienced stone surgeon operating at an academic comprehensive stone center between April and December 2011. Radiation exposure measurements were determined by a thermoluminescent dosimeter worn on the outside of the surgeon's thyroid shield. Estimations of radiation exposure (mrem) per month were charted with fluoroscopy times, using scatter plots to estimate Spearman's rank correlation coefficients. Results The total 9-month radiation exposure was 87 mrems for deep dose equivalent (DDE), 293 mrem for lens dose equivalent (LDE), and 282 mrem for shallow dose equivalent (SDE). Total fluoroscopy time was 252.44 minutes for 64 ureteroscopies (URSs), 29 percutaneous nephrolithtomies (PNLs), 20 cystoscopies with ureteral stent placements, 9 shock wave lithotripsies (SWLs), 9 retrograde pyelograms (RPGs), 2 endoureterotomies, and 1 ureteral balloon dilation. Spearman's rank correlation coefficients examining the association between fluoroscopy time and radiation exposure were not significant for DDE (p = 0.6, Spearman's rho = 0.2), LDE (p = 0.6, Spearman's rho = 0.2), or SDE (p = 0.6, Spearman's rho = 0.2). Conclusions Over a 9-month period, total radiation exposures were well below annual accepted limits (DDE 5000 mrem, LDE 15,000 mrem and SDE 50,000 mrem). Although fluoroscopy time did not correlate with radiation exposure, future prospective studies can account for co-variates such as patient obesity and urologist distance from radiation source. .

Efficacy of a Self-designed Protective Lead Shield in Reduction of Radiation Exposure Dose During Endoscopic Retrograde Cholangiopancreatography / 대한소화기학회지

BACKGROUND/AIMS: The increasing use of diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP) calls for greater consideration of radiation exposure risk to endoscopists and assistants, and emphasizes the proper system of radiation protection. This study was designed to assess the effect of a newly developed, self-designed, protective lead shield. METHODS: A curtain-shaped protective shield composed of seven movable lead plates was developed, each with the following dimensions: depth, 0.1 cm; width, 15 cm; length, 70 cm. The curtain-shaped protective shield was designed to be located between the patient and the endoscopist. Twenty-nine patients (11 men and 18 women) undergoing ERCP between January 2010 and March 2010 were selected for this study. The dose of radiation exposure was recorded with or without the protective lead shield at the level of the head, chest, and pelvis. The measurement was made at 50 cm and 150 cm from the radiation source. RESULTS: The mean patient age was 64 years. The mean patient height and weight was 161.7+/-6.9 cm and 58.9+/-9.9 kg, respectively. The mean body mass index (BMI) was 22.5+/-3.0 kg/m2. Endoscopists received 1522.2+/-537.0 mR/hr without the protective lead shield. At the same distance, radiation exposure was significantly reduced to 68.8+/-88.0 mR/hr with the protective lead shield (p-value<0.0001). The radiation exposure to endoscopists and assistants was significantly reduced by the use of a protective lead shield (p value<0.0001). The amount of radiation exposure during ERCP was related to the patient's BMI (r=0.749, p=0.001). CONCLUSIONS: This self-designed, protective lead shield is effective in protecting endoscopists and assistants from radiation exposure.

[Effective dose rate of radon gas in Jooshan hot spring of Kerman Province]

Human beings are constantly exposed to different radiations that have always been recognized as a health hazard. Radon-222 and its daughter products are major sources of natural radiations and a significant total inhalation dose is related to them. Hence, the measurement of radon activity in the environment has gained an increasing importance. In this study, with the measurement of radon concentration, the indoor radon activity level and radon effective dose rate in Jooshan hot spring were determined. Concentration of radon gas inside the pool of Jooshan hot spring was measured using the active detector Rad7 type and the annual effective dose was estimated for individuals inhaling the indoor air of this pool for a specified period of time. Concentration of indoor air radon gas was 98.3 +/- 4.9 Bq/m3 and for a person staying in the pool twice a week and each time for two hours, the annual effective dose rate, due to the inhalation of radon, equals to 0.06 +/- 0.003 mSv/y. Comparison of the obtained effective dose with the standards of Environmental protection Agency and Health physics Society, it can be concluded that for individuals that normally use Jooshan hot spring pool, the resulted dose is in the recommended range

Desigualdade social e exposição a campos magnéticos na região metropolitana de São Paulo / Desigualdad social y exposición a campos magnéticos en la región metropolitana de Sao Paulo / Social inequality and exposure to magnetic fields in the metropolitan region of São Paulo, Southeastern Brazil

OBJETIVO: Estimar a prevalência de exposição aos campos magnéticos gerados por linhas de transmissão (LT) e caracterizar a população exposta. MÉTODOS: Informações sobre LT da Região Metropolitana de São Paulo foram fornecidas pelas concessionárias de energia e mapeadas usando sistema de informação geográfica (SIG). Dados demográficos e socioeconômicos foram obtidos por meio do Censo 2000 e incluídos no SIG em outra camada. Foram considerados expostos os domicílios e seus habitantes localizados a uma distância da LT suficiente para gerar um campo magnético 0,3 µT (microteslas). A prevalência foi estimada por meio da área de corredores de exposição ao longo das LT. A largura dos corredores de exposição se baseou em duas abordagens: uma consistiu em larguras pré-definidas pela tensão da LT e a outra por meio de cálculo do campo magnético. As informações socioeconômicas entre expostos e não expostos foram comparadas pela aplicação do teste de duas proporções (α= 5 por cento)...

OBJECTIVE: To estimate the prevalence of exposure to magnetic fields generated by transmission lines (TL) and characterize the exposed population. METHODS: Information about TL in the metropolitan region of São Paulo, Southeastern Brazil, was provided by the electricity companies and mapped out using geographic information system (GIS). Demographic and socioeconomic data were obtained from the 2000 Census and added to the GIS in another layer. Households and their inhabitants that were located at a distance from the TL that was sufficient to generate a magnetic field 0.3 µT (microteslas) were deemed to be exposed. The prevalence was estimated according to the area of the corridors of exposure along the TL. Two approaches were used to delimit the corridor width: one consisted of widths that were predefined by the TL voltage, and the other consisted of calculation of the magnetic field. The socioeconomic information on the exposed and non-exposed populations were compared by applying the two-proportion test (α= 5 percent)...

OBJETIVO: Estimar la prevalencia de exposición a los campos magnéticos generados por líneas de transmisión (LT) y caracterizar la población expuesta. MÉTODOS: Informaciones sobre LT de la Región Metropolitana de São Paulo (Sureste de Brasil) fueron providenciadas por las concesionarias de energía y mapeadas usando el sistema de información geográfica (SIG). Datos demográficos y socioeconómicos fueron obtenidos por medio del Censo 2000 e incluidos en el SIG en otra camada. Fueron considerados expuestos los domicilios y sus habitantes localizados a una distancia de la LT suficiente para generar un campo magnético 0,3 μT (microteslas). La prevalencia fue estimada por medio del área de corredores de exposición a lo largo de las LT. El ancho de los corredores de exposición se basó en dos abordajes: uno consistió en anchos pre-definidos por la tensión de la LT y la otra por medio del cálculo del campo magnético. Las informaciones socioeconómicas entre expuestos y no expuestos fueron comparadas por la aplicación de la prueba de dos proporciones (α=5 por ciento)...

[Assessment of indoor gamma radiation and related annual effective dose in Zanjan, Iran]

Due to importance of ionizing radiation on human health, many studies have been performed to measure the background gamma radiation all around the world as well as some cities in lran. According to this fact that everybody spends almost 80% of his time in indoor areas, this study was carried out to measure the amount of background gamma radiation in indoor areas in Zanjan city located in northwest of Iran to determine the annual effective dose of the city residents. To determine the dose rate of background gamma radiation in indoors, 30 dwelling [in the main geographical directions and in the downtown areas] were selected. All of them were one floor and iron roofed. A Geiger-Muller detector [RDS-110] calibrated by Cs-137 was used in each livings room of each dwellings that performed in one meter far from the earth. In 30 minute 30 values was recorded. The mean value was considered as indoor gamma dose rate in each dwelling. The mean value of dose rate in Zanajn indoor areas due to gamma background radiation was determined 146 +/- 25 nGy/h. According to the results and findings in our previous study about gamma background radiation in outdoor areas in Zanjan, the annual effective dose was determined and 0.87 mSv for Zanjan city residents. The annual effective dose of Zanjan city residents due to the gamma background radiation is 0.87 mSv that in comparison with UNSCEAR-2000 report is higher than the mean value for the world [0.48 mSv]

Avaliação do ambiente eletromagnético em estabelecimentos assistenciais de saúde / Electromagnetic environment assessment in health care facilities

A crescente inserção de tecnologia eletroeletrônica em estabelecimentos assistenciais de saúde (EAS), seja como equipamentos terapêuticos, de diagnóstico ou até mesmo suporte vital, tem sido vista pela comunidade científica como a grande responsável pelo aumento dos níveis de energia eletromagnética emitidos ao ambiente hospitalar. Dessa forma, quando a energia eletromagnética presente no ambiente atinge um determinado nível crítico, fica estabelecida uma situação que é propícia ao aparecimento de dois fenômenos indesejados: a interferência eletromagnética (EMI) em equipamentos médicos, e os riscos biológicos (RBL) em seres vivos. Um importante recurso para gerenciar a compatibilidade eletromagnética e evitar o aparecimento destes fenômenos é o conhecimento das características eletromagnéticas presentes nestes ambientes. O objetivo deste trabalho é diagnosticar o comportamento eletromagnético estabelecido em ambientes de grande concentração de fontes emissoras como, por exemplo, o encontrado em centros cirúrgicos, através de uma série de medições in situ das grandezas eletromagnéticas envolvidas nestes meios (campos elétricos, campos magnéticos, ruídos conduzidos). Com base nestas medidas é realizada uma avaliação crítica de modo a comparar a situação estabelecida nos EAS e os limites de segurança preconizados por organismos competentes, tanto para EMI quanto para RBL. Como resultado desta análise, começa a existir maior discernimento quanto à real situação do ambiente eletromagnético encontrado em EAS nacionais, subsidiando informações para a definição de diretrizes mais eficientes para implementação de programas de gestão tecnológica que são direcionados às necessidades específicas destes hospitais.

Advances in technology and the increased use of electro-medical equipment (EME) to support medical procedures such as monitoring, diagnosis, therapeutic or even life support are considered as greatly responsible for the increase of electromagnetic energy within health care facilities (HCF) environments. In such circumstances, when electromagnetic energy reaches a certain critical level, a dangerous situation is established and two undesirable phenomena can take place, both electromagnetic interference (EMI) in medical equipment, and biological risks (BLR) in living beings. The knowledge of electromagneticcharacteristics shown by these environments can represent an important tool in order to promote electromagnetic compatibility and avoid the appearance of undesirable phenomena. Therefore, this work aims to diagnose the electromagnetic profile established in critical areas, such as operating rooms, through a number of “in situ” measurements concerning electromagnetic quantities present in this environment (electric field, magnetic field, conducted noise). Moreover, a critical evaluation follows in order to compare the establishedsituation within HCF and the safety levels prescribed by regulatory organizations regarding EMI and BLR. As a result of this assessment, a better understanding on the actual situation concerning the electromagnetic environment in HCF can be achieved, allowing clinical engineers to define better directives in order to implement an adequate management programs in these hospitals.

Evaluation of radiation dose to patients during abdominal embolizations.

BACKGROUND: Abdominal embolization procedures performed using digital subtraction angiography (DSA) is on the increase in the present-day scenario owing to their diagnostic and therapeutic values. These procedures involve prolonged fluoroscopy times and may tend to impart high radiation dose to patients if adequate radiation safety measures are not taken. AIM: To evaluate radiation dose imparted to patients and the work practices involved therein during abdominal embolization procedures. MATERIALS AND METHODS: Forty-two patients who underwent abdominal embolizations performed using DSA equipment were included in the study. Dose area product (DAP) was measured using DAP meter and values obtained were used for calculating entrance surface dose (ESD). Work practices of personnel involved in conducting the procedure were evaluated based on the choice of field sizes, selection of appropriate fluoro-modes, and optimization techniques. RESULTS AND CONCLUSIONS: The mean ESD values during hepatic embolization, renal embolization, splenic artery embolization and transarterial chemoembolization (TACE) were 1.2, 1.01, 1.19, and 1.03, respectively. No deterministic effects of radiation, such as transient or main erythema, were noticed for a few patients whose doses exceeded the threshold doses.

Uranium, radium and radon exhalation studies in geological samples belonging to some areas of punjab, using track etching technique.

With a view to prospect the uranium, radium and radon concentration and related health risk assessments in areas of Muktsar and Ferozepur districts in Punjab, the fission track registration technique has been used for the analysis of water and soil samples. Uranium content in water ranged from 5.47 to 10.19 microg/l(-1) and 6.28 to 11.74 microg/l(-1) for Muktsar and Ferozepur respectively. Uranium content in soil samples of Muktsar and Ferozepur ranged from 1.14 to 1.90 mg/kg(-1) and 1.26 to 2.44 mg/kg(-1) respectively. Radium concentration in these soil samples has been found to vary from 3.97 to 15.94 bq/kg(-1) and 7.24 to 24.14 bq/kg(-1) for Muktsar and Ferozepur respectively. The radon exhalation values were calculated in terms of area (E(A)) and mass (E(M)). The values of E(M) ranged from 4.9 to 20.6 (mbqkg(-1) hr(-1)) for Muktsar and 9.4 to 31.3 (mbqkg(-1)hr(-1)) for Ferozepur and values of E(A) ranged from 173 to 728 (mbqm(-2)hr(-1)) for Muktsar and 330 to 1102 (mbqm(-2)hr(-1)) for Ferozepur district. These values in general are low and not significant from health hazard point of view. The values of uranium concentration in water samples of these areas are lower than those reported for soil and water samples of Himachal Pradesh. These values are also lower than those reported by Singh et al. for the rocks belonging to uranium and copper mines of Bihar.

Thermoluminescence dosimetry in the Caribbean

The results of five years of radiation monitoring of 590 radiation workers in Jamaica and an additional 88 in Barbados and The Turks and Caicos Islands show that the annual dose absorbed by Caribbean radiation workers is, with a single exception, well within the internationally accepted limits of 20 mSv per year. There were few cases of relatively high exposures. The dose equivalent of the radiation workers by category agrees with international trends; workers in nuclear medicine receive the highest doses and dental radiologists the lowest. The collective Effective Dose Equivalent has been calculated for each of the monitored populations and certain trends identified. The risk for development of fatal cancers from the occupational doses reported was very low. Consistent monitoring will identify aberrant conditions quickly and help maintain that record

Radiación ultravioleta en Chile: variaciones con la altura y la latitud / Ultraviolet radiation in Chile: variations with altitude and latitude

Chile tiene un territorio continental ubicado entre los 18º-56º de latitud sur y abarcan zonas entre el nivel del mar y los 5.000 metros de altura. Sus habitantes deben viajar a lo largo y ancho del territorio, ya sea por razones de negocios, oportunidades de trabajo, deportes o turismo, por lo cual están constantemente sometidos a variaciones del régimen de radiación ultravioleta. El objetivo de esta presentación es ofrecer una visión preliminar de las dosis diarias de eritema (DDE) a lo largo y ancho del país. Con un radiómetro portátil de cuatro canales en el UV se realizaron mediciones desde la salida hasta la puesta del sol en diferentes lugares entre los 18º y 53º S) en invierno y verano. A través del método de inversión se recuperó el espectro UV completo, minuto a minuto en pocos días de cada lugar de medición. Usando el espectro de acción (CIE) para eritema fueron estimadas las dosis diarias. Se comparan los valores de DDE de los lugares analizados para obtener un primer vistazo de los cambios debidos a latitud y altura. En general, los cambios por diferencias de altura o latitud son mayores en invierno que en verano. por otra parte, las personas que se desplazan 1.000 km de sur a norte en invierno se someten a un mayor estrés que si suben 1.000 metros en la cordillera

Impacto de la radiación secundaria en el operador durante la arteriografía coronaria selectiva / Secondary irradiation of operators during coronary arteriography

Background: The activity over cellular genetic pattern of ionizing radiation can produce stochastic and unspecific damages. Interventional cardiology operators have increasing exposure times to ionizing radiation and there is no information about the real protection conferred by simple radiological protection devices. Aim: To assess the magnitude of secondary ionizing radiation exposure of operators during conventional coronary arteriography, evaluating the radiation exposure during different beam projections and the usefulness of leaded aprons. Material and methods: Ionizing radiation received by operators during coronary arteriography was measured using a Geiger-Müller Victoreen model 490 counter. The device was placed in the ventral region, covered by the leaded apron and in the unprotected dorsal region. Radiation was measured in right and left projections during fluoroscopy and shooting. Results: In right projection, the intensity of ionizing radiation in ventral and dorsal regions was 1.24 ñ 1.1 and 2.9 ñ 4 mR/h respectively (p= 0.08). In left projection, the figures were 2.95 ñ 3 and 7.86 ñ 7.2 mR/h respectively (p= 0.001). During shooting in left projection the radiation exposure in ventral and dorsal regions was 9.66 ñ 6.7 and 32.8 ñ 27 mR/h respectively (p< 0.001). During shooting in right projection that figures were 10.1 ñ 16 and 20.7 ñ 39.8 mR/h respectively (p= 0.09). No correlation between radiation exposure and patients surface area was observed. Conclusions: Secondary radiation received by operators is higher during shooting and in left projections. Leaded apron confers a partial protection for ventral region, and great fluctuations in the magnitude of radiation exposure were recorded. Unprotected dorsal region receives a greater amount of radiation in left projections

Avaliaçäo de materiais atenuadores: modelo para a distribuiçäo da radiaçäo espalhada / Evaluation of attenuating materials: model to radiaton scattered distribuition

O presente trabalho introduz um modelo matemático para o comportamento da distribuição de fótons espalhados por meios atenuadores. Estes meios podem ser barreiras radioprotetoras ou materiais atenuadores utilizados em ensaios ou programas de controle de qualidade em radiologia. São apresentados resultados comparativos para Lucite.

Resultados da implantaçäo de um programa de proteçäo radiológica no serviço de radioterapia/CAISM-UNICAMP / Results of implantation of a radiological protection program in radiotherapy service/CAISM - UNICAMP

Para verificar as condições de proteção radiológica no Serviço de Radioterapia/CAISM - UNICAMP, foi elaborado um programa de proteção radiológica específico, composto do plano de radioproteção do serviço, de um programa de monitorações de área e individual e de um programa de auditorias. Sua implantação utilizou medidores Geiger-Müller, câmaras de ionização, fichas de auditoria específicas e resultados de cerca de cinco anos de monitoração individual. Os resultados mostram que todas as áreas onde são armazenados ou utilizados aparelhos e/ou fontes são classificadas como áreas controladas e que todos os trabalhadores têm doses equivalentes inferiores aos limites para indivíduos do público. Dos itens auditados, somente 3,5 por cento estão em desacordo com as recomendações de proteção radiológica devido à deficiências do serviço.

Estudo comparativo de duas décadas,[73-82] e [86-95], de monitorizaçäo individual hospitalar / Comparative study of two decades, [73-82] e [86-95], of hospitalar individual monitoring

As doses individuais de duas décadas do H.C.F.M.R.P-USP foram analisadas. Desta análise as doses médias anuais individuais de vários serviços do hospital foram comparadas, assim como as doses por categoria de trabalhador Dos dados obtidos classificamos os trabalhadores nas condições de trabalho A e B recomendadas pela ICRP 35. Também foi possível comparar três tipos de monitoração individual (filme, CaSO4 e LiF + CaSO4), realizadas por laboratórios diferentes, observando-se boa concordância entre eles.

Comportamento de monitores portáteis em feixes de radiaçäo X de baixas energias / Behavioral of portable monitors in low energy X-rays fields

No Laboratório de Calibração de instrumentos do IPEN os monitores portáteis são calibrados com radiação gama de (60)Co e (137)Cs; no entanto, sabe-se que muitos destes instrumentos são utilizados para medidas em campos de radiação X até mesmo na faixa em que apresentam dependência energética acentuada. Este trabalho consiste no estudo da resposta de monitores portáteis expostos a feixes de radiação X de baixas energias.

Monitoramento e avaliaçäo de uma câmara escura / Monitoring and evaluation of a dark chamber

As condições de operação de uma câmara escura devem ser tais que possibilitem a maior eficiência do Serviço de Radiologia. Os cuidados com as etapas que nela se desenrolam devem ser minuciosos tendo em vista que a menor falha comprometerá todo o processo radiológico. Tal comprometimento, implicará na repetição do procedimento radiográfico expondo desnecessariamente paciente e profissionais envolvidos à radiação ionizante. Além disso, esse fato acarretará, também, em gastos adicionais para a instituição. Para averiguar a integridade e o funcionamento da câmara escura, foram propostos testes básicos que traduziram as reais condições de operação das câmaras escuras avaliadas.

The operating conditions of the Darkroom should be possibility to inérease efficiency of Radiologic Service. The cares with the steps developed on the Darkroom should be circunstantial and the minor mistake will compromisse the radiologic process. This compromisse will implicate on the repetition of all radiographic procedures, exposed unnecessarily patients and professionals involved in ionize radiation. ln addiction, also this fact will cause additional costs to institution. To verify the Darkroom's integrity and performance, had proposed basic tests that express the real conditions of the avaliated darkroom's.

Investigación sobre niveles de dosis en exámenes con fluoroscopia gastrointestinal como parte de un programa de control de calidad / An investigation of the levels of radiation exposure in diagnostic examinations involving gastrointestinal tract fluoroscopy

El Servicio de Radiodiagnóstico del Hospital Universitario de la Universidad Federal de Río de Janeiro, juntamente con el Instituto de Radioprotección y Densitometría de la Comisión Nacional de Energía Nuclear, se encuentra desarrolllando programas en el área de garantía de calidad en radiodiagnóstico. Estas actividades contemplan como objetivo importante la optimización de las dosis. Uno de los programas en marcha comprende exámenes de fluoroscopia gastrointestinal. A fin de investigar los niveles de exposición a la radiación fueron realizadas medidas de dosis de entrada en la piel recibidas por pacientes y médicos en exámenes de esofagografía, seriografía y colon, utilizando dosímetros colocados en varias posiciones del cuerpo. En este trabajo se describe la metodología seguida y se muestran los resultados obtenidos hasta el presente. Se hace un análisis del espectro de dosis observadas en pacientes y profesionales, de acuerdo con diversos parámetros tales como ubicación de dosímetros, tiempo de exposición, técnicas empleadas, número de radiografías, etc. También se describen los pasos a seguir con el objeto de concretar la implantación de un programa de control de calidad en los exámenes mencionados