RESUMO

Purpose: The aim of this study was to evaluate the influence of different cone-beam computed tomography (CBCT) acquisition protocols on reducing the effective radiation dose while maintaining image quality. Materials and Methods: The effective dose emitted by a CBCT device was calculated using thermoluminescent dosimeters placed in a Rando Alderson phantom. Image quality was assessed by 3 experienced evaluators. The relationship between image quality and confidence was evaluated using the Fisher exact test, and the agreement among raters was assessed using the kappa test. Multiple linear regression analysis was performed to investigate whether the technical parameters could predict the effective dose. P-values<0.05 were considered to indicate statistical significance. Results: The optimized protocol (3 mA, 99 kVp, and 450 projection images) demonstrated good image quality and a lower effective dose for radiation-sensitive organs. Image quality and confidence had consistent values for all structures (P<0.05). Multiple linear regression analysis resulted in a statistically significant model. The milliamperage (b=0.504; t=3.406; P=0.027), kilovoltage peak (b=0.589; t=3.979; P=0.016) and number of projection images (b=0.557; t=3.762; P=0.020) were predictors of the effective dose. Conclusion: Optimized CBCT acquisition protocols can significantly reduce the effective radiation dose while maintaining acceptable image quality by adjusting the milliamperage and projection images.

RESUMO

The purpose of this study is to evaluate radiation exposure in newborns undergoing imaging tests during the first 30 days of neonatal intensive care unit (NICU) hospitalization. A retrospective cohort study was conducted from November 2018 to April 2019 with newborns admitted to the NICU. Thermoluminescent dosimeters (TLD-100™) measured radiation emitted during imaging exams over 1 month, with a comparison between measured and estimated radiation. The cohort exhibited a median gestational age of 33.0 (31.0, 37.0) weeks, a median birth weight of 1840 (1272, 2748) g, and a median length of stay of 25.5 (11.7, 55.0) days. Eighty-four patients underwent 314 imaging tests, with an estimated radiation dose (ERD) per patient of 0.116 mSv and a measured radiation dose (MDR) of 0.158 mSv. ERD consistently underestimated MDR, with a mean difference of -0.043 mSv (-0.049 to -0.036) in the Bland-Altman analysis. The regression equation was as follows: difference MRD - ERD = -1.7 × (mean (MRD + ERD)) + 0.056. The mean estimated radiation dose per exam was 0.030 mSv, and the chest X-rays accounted for 63.26% of total exams. The median number of radiographic incidences per patient was 2 (1, 4), with 5 patients undergoing three or more exams in a single day. CONCLUSION: Radiation exposure in these newborns was underestimated, emphasizing the need for awareness regarding associated risks and strict criteria for requesting radiological exams. Lung ultrasound is a radiation-free and effective option in managing respiratory diseases in newborns, reducing the reliance on chest X-rays. WHAT IS KNOWN: • Radiation used in diagnostic exams is not risk-free. • Radiation risk is much higher in small Infants due to the exposure area and the prolonged expectance of life. WHAT IS NEW: • Radiation exposure is underestimated in the neonatal population. • The study found a mean radiation exposure in neonates about 5% of the mean annual dose in the general population.

Assuntos

RESUMO

INTRODUCTION: in general, spine surgeons seek to minimize soft tissue damage by using less invasive approaches, which causes them to use intraoperative images much more frequently than other surgical specialties; therefore, they are at increased risk of radiation exposure. OBJECTIVE: the aim of this work was to analyse the amount of radiation to which the spine surgeon is exposed in different scenarios. MATERIAL AND METHODS: a prospective study with a descriptive, longitudinal non-randomized data source. We carried out this study in the period from 2015 to 2019, the radiologic protection consisted in lead apron, thyroid shield and leaded glasses, there were 10 badge dosimeters. RESULTS: only 4 dosimeters were included in the study, the other six were excluded. During the study period one surgeon suffered thyroid cancer and other suffered of liposarcoma. In the protected group were two surgeons, in the group of aleatory exposition was one surgeon and in the unprotected group was one surgeon. In the study the dosimeter in the unprotected group received more amount of radiation in all the years, we did an inferential analysis per year related with the number of surgeries without significant correlation, we attribute this result because we didn't classified the type of surgery realized by each surgeon. CONCLUSION: we conclude that the spine surgeon must apply the primary methods of radiological protection and that the unprotected spine surgeon receives more amount of radiation in comparison of the protected ones.

INTRODUCCIÓN: en general, los cirujanos de columna buscan minimizar el daño a tejidos blandos empleando abordajes menos invasivos, lo que ocasiona que utilicen imágenes intraoperatorias de una manera mucho más habitual que el resto de las especialidades quirúrgicas; por lo tanto, están en mayor riesgo de exposición de radiación. OBJETIVO: el propósito del trabajo es analizar la cantidad de radiación a la cual está expuesto el cirujano de columna en diferentes escenarios. MATERIAL Y MÉTODOS: estudio prospectivo con una fuente de datos descriptiva, longitudinal, no aleatorizada. Se llevó a cabo el estudio en el período del año 2015 al 2019; la protección radiológica consistió en chaleco plomado, protector de tiroides y lentes plomados; se usaron 10 dosímetros. RESULTADOS: cuatro dosímetros fueron incluidos en el estudio, los otros seis fueron excluidos. Durante el estudio, un cirujano sufrió de cáncer de tiroides y otro de liposarcoma. En el grupo de protegidos se incluyeron dos cirujanos, en el grupo de protección aleatorizada se incluyó un cirujano y en el grupo sin protección se incluyó un cirujano. El dosímetro del grupo sin protección recibió mayor cantidad de radiación en todos los años, se realizó un análisis inferencial por año relacionado con el número de cirugías no encontrando correlación significativa, atribuimos este resultado a que no clasificamos el tipo de cirugía realizada por cada cirujano. CONCLUSIÓN: el cirujano de columna debe de aplicar los métodos primarios de protección radiológica, ya que los cirujanos de columna sin equipo de protección reciben mayor cantidad de radiación en comparación con los protegidos.

Assuntos

RESUMO

Mycobacterium bovis BCG Moreau is the main Brazilian strain for vaccination against tuberculosis. It is considered an early strain, more like the original BCG, whereas BCG Pasteur, largely used as a reference, belongs to the late strain clade. BCG Moreau, contrary to Pasteur, is naturally deficient in homologous recombination (HR). In this work, using a UV exposure test, we aimed to detect differences in the survival of various BCG strains after DNA damage. Transcription of core and regulatory HR genes was further analyzed using RT-qPCR, aiming to identify the molecular agent responsible for this phenotype. We show that early strains share the Moreau low survival rate after UV exposure, whereas late strains mimic the Pasteur phenotype, indicating that this increase in HR efficiency is linked to the evolutionary clade history. Additionally, RT-qPCR shows that BCG Moreau has an overall lower level of these transcripts than Pasteur, indicating a correlation between this gene expression profile and HR efficiency. Further assays should be performed to fully identify the molecular mechanism that may explain this differential phenotype between early and late BCG strains.

RESUMO

Resumen: Introducción: en general, los cirujanos de columna buscan minimizar el daño a tejidos blandos empleando abordajes menos invasivos, lo que ocasiona que utilicen imágenes intraoperatorias de una manera mucho más habitual que el resto de las especialidades quirúrgicas; por lo tanto, están en mayor riesgo de exposición de radiación. Objetivo: el propósito del trabajo es analizar la cantidad de radiación a la cual está expuesto el cirujano de columna en diferentes escenarios. Material y métodos: estudio prospectivo con una fuente de datos descriptiva, longitudinal, no aleatorizada. Se llevó a cabo el estudio en el período del año 2015 al 2019; la protección radiológica consistió en chaleco plomado, protector de tiroides y lentes plomados; se usaron 10 dosímetros. Resultados: cuatro dosímetros fueron incluidos en el estudio, los otros seis fueron excluidos. Durante el estudio, un cirujano sufrió de cáncer de tiroides y otro de liposarcoma. En el grupo de protegidos se incluyeron dos cirujanos, en el grupo de protección aleatorizada se incluyó un cirujano y en el grupo sin protección se incluyó un cirujano. El dosímetro del grupo sin protección recibió mayor cantidad de radiación en todos los años, se realizó un análisis inferencial por año relacionado con el número de cirugías no encontrando correlación significativa, atribuimos este resultado a que no clasificamos el tipo de cirugía realizada por cada cirujano. Conclusión: el cirujano de columna debe de aplicar los métodos primarios de protección radiológica, ya que los cirujanos de columna sin equipo de protección reciben mayor cantidad de radiación en comparación con los protegidos.

Abstract: Introduction: in general, spine surgeons seek to minimize soft tissue damage by using less invasive approaches, which causes them to use intraoperative images much more frequently than other surgical specialties; therefore, they are at increased risk of radiation exposure. Objective: the aim of this work was to analyse the amount of radiation to which the spine surgeon is exposed in different scenarios. Material and methods: a prospective study with a descriptive, longitudinal non-randomized data source. We carried out this study in the period from 2015 to 2019, the radiologic protection consisted in lead apron, thyroid shield and leaded glasses, there were 10 badge dosimeters. Results: only 4 dosimeters were included in the study, the other six were excluded. During the study period one surgeon suffered thyroid cancer and other suffered of liposarcoma. In the protected group were two surgeons, in the group of aleatory exposition was one surgeon and in the unprotected group was one surgeon. In the study the dosimeter in the unprotected group received more amount of radiation in all the years, we did an inferential analysis per year related with the number of surgeries without significant correlation, we attribute this result because we didn't classified the type of surgery realized by each surgeon. Conclusion: we conclude that the spine surgeon must apply the primary methods of radiological protection and that the unprotected spine surgeon receives more amount of radiation in comparison of the protected ones.

RESUMO

Objective: To measure the potential radiation dose emitted by patients who have recently undergone diagnostic nuclear medicine procedures, in order to establish optimal radiation safety measures for such procedures. Materials and Methods: We evaluated the radiation doses emitted by 175 adult patients in whom technetium-99m, iodine-131, and fluorine-18 radionuclides were administered for bone, kidney, heart, brain, and whole-body scans, as measured with a radiation detector. Those values served as the basis for evaluating whole-body radiopharmaceutical clearance, as well as the risk for the exposure of others to radiation, depending on the time elapsed since administration of the radiopharmaceutical. Results: The mean time to clearance of the radiopharmaceuticals administered, expressed as the effective half-life, ranged from 1.18 ± 0.30 h to 11.41 ± 0.02 h, and the mean maximum cumulative radiation dose at 1.0 m from the patients was 149.74 ± 56.72 µSv. Even at a distance of 0.5 m, the cumulative dose was found to be only half and one tenth of the limits established for exposure of the general public and family members/caregivers (1.0 mSv and 5.0 mSv per episode, respectively). Conclusion: Cumulative radiation doses emitted by patients immediately after diagnostic nuclear medicine procedures are considerably lower than the limits established by the International Commission on Radiological Protection and the International Atomic Energy Agency, and precautionary measures to avoid radiation exposure are therefore not required after such procedures.

Objetivo: O objetivo deste trabalho foi levantar o potencial de dose de radiação emitida por pacientes em procedimentos diagnósticos, visando a estabelecer cuidados de radioproteção mais otimizados. Materiais e Métodos: Taxas de dose de radiação emitidas por 175 pacientes administrados com os radionuclídeos 99mTc, 131I e 18F para cintilografias óssea, renal, cardíaca, cerebral e corpo inteiro, foram mensuradas com um detector de radiação, servindo para avaliar o clareamento do radiofármaco no organismo e risco de exposição após administração dos radiofármacos. Resultados: O clareamento, representado pela meia-vida efetiva, variou de 1,18 ± 0,30 h até 11,41 ± 0,02 h e a dose de radiação máxima acumulada oferecida pelos pacientes a 1,0 m foi de 149,74 ± 56,72 µSv. Mesmo para distâncias de 0,5 m, as doses estimadas foram, respectivamente, duas e dez vezes inferiores ao nível de restrição para o público geral (1,0 mSv) e exposição médica (5,0 mSv/episódio). Conclusão: Doses de radiação oferecidas por pacientes em procedimentos diagnósticos são inferiores aos níveis de restrição recomendados pela International Commission on Radiological Protection e International Atomic Energy Agency, e assim, cuidados de radioproteção são geralmente desnecessários.

RESUMO

BACKGROUND: The transradial approach (TRA) to coronary angiography reduces vascular complications but is associated with greater radiation exposure than the transfemoral approach (TFA). It is unknown whether exposure remains higher when TRA is performed by experienced operators. METHODS: Patients were randomly, prospectively assigned to TRA or TFA. The primary end point was patient radiation dose; secondary end points were the physician radiation dose and 30-day major adverse cardiac event rate. Coronary angiography was performed by experienced operators using a standardized protocol. RESULTS: Clinical and procedural characteristics were similar between the TRA (n = 150) and TFA (n = 149) groups, and they had comparable mean (SD) radiation doses for patients (616.51 [252] vs 585.57 [225] mGy; P = .13) and physicians (0.49 [0.3] vs 0.46 [0.29] mSv; P = .32). The mean (SD) fluoroscopy time (3.52 [2.02] vs 3.13 [2.46] min; P = .14) and the mean (SD) dose area product (35,496.5 [15,670] vs 38,313.4 [17,764.9] mGy·cm2; P = .2) did not differ. None of the following factors predicted higher radiation doses: female sex (hazard ratio [HR], 0.69 [95% CI, 0.38-1.3]; P = .34), body mass index >25 (HR, 0.84 [95% CI, 0.43-1.6]; P = .76), age >65 years (HR, 1.67 [95% CI, 0.89-3.1]; P = .11), severe valve disease (HR, 1.37 [95% CI, 0.52-3.5]; P = .68), or previous coronary artery bypass graft (HR, 0.6; 95% CI, 0.2-1.8; P = .38). CONCLUSION: TRA for elective coronary angiography is noninferior to TFA when performed by experienced operators.

Assuntos

RESUMO

Abstract The study aimed to assess the influence of excessive use of a photostimulable phosphor plate (PSP) on the density, image noise, and contrast of radiographs. For that, radiographs of an acrylic block were acquired with a PSP of the Express intraoral system to assess the density and image noise. Initially, five images were obtained and exported (first group). After 400 exposures to X-rays and scannings of PSP, other five images were obtained and exported (second group). The same procedure was done after 800 (third group), 1200 (fourth group), 1600 (fifth group), and 2000 acquisitions (sixth group), resulting in 30 images to be evaluated. The mean and standard deviation of the gray values were calculated for the images using the ImageJ software. For contrast analysis, radiographs of an aluminum step-wedge were acquired with a new PSP following the same acquisition intervals. The percentage of contrast variation was calculated. Another two unused PSP receptors were employed to evaluate the method's reproducibility. The comparison of the results among the acquisition groups was performed with one-way Analysis of Variance (α=0.05). Intraclass Correlation Coefficient (ICC) assessed the reproducibility of the receptors. Image noise did not differ among the groups (p>0.05). There was a slight increase in density after 400 acquisitions and a slight difference in contrast for all acquisition groups without a pattern of increase or decrease (p<0.05). ICC showed excellent reliability for the methods. Therefore, excessive PSP use slightly affected the radiograph's density and contrast.

Resumo Objetivou-se avaliar a influência do uso excessivo de uma placa de fósforo fotoestimulável (PSP) na densidade, ruído e contraste das radiografias. Foram adquiridas radiografias de um bloco de acrílico com uma PSP do sistema intraoral Express para avaliar a densidade e o ruído da imagem. Inicialmente, cinco imagens foram obtidas e exportadas (primeiro grupo). Após 400 exposições aos raios X e escaneamentos, outras cinco imagens foram obtidas e exportadas (segundo grupo). O mesmo procedimento foi feito após 800 (terceiro grupo), 1200 (quarto grupo), 1600 (quinto grupo) e 2000 aquisições (sexto grupo), resultando em 30 imagens a serem avaliadas. A média e o desvio padrão dos valores de cinza foram calculados para as imagens usando o software ImageJ. Para análise de contraste, foram adquiridas radiografias de uma escala de alumínio com uma nova PSP seguindo os mesmos intervalos de aquisição. A porcentagem de variação do contraste foi calculada. Outras duas PSP sem uso prévio foram utilizadas para avaliar a reprodutibilidade dos métodos. A comparação dos resultados entre os grupos de aquisição foi realizada pela Análise de Variância one-way (α=0,05). O Coeficiente de Correlação Intraclasse (ICC) avaliou a reprodutibilidade dos receptores. O ruído da imagem não diferiu entre os grupos (p>0,05). Houve um leve aumento na densidade após 400 aquisições e uma pequena diferença no contraste para todos os grupos de aquisição sem padrão de aumento ou diminuição (p<0,05). O ICC mostrou excelente confiabilidade para os métodos. Portanto, o uso excessivo da PSP afetou levemente a densidade e o contraste radiográfico.

RESUMO

Abstract Objective: To measure the potential radiation dose emitted by patients who have recently undergone diagnostic nuclear medicine procedures, in order to establish optimal radiation safety measures for such procedures. Materials and Methods: We evaluated the radiation doses emitted by 175 adult patients in whom technetium-99m, iodine-131, and fluorine-18 radionuclides were administered for bone, kidney, heart, brain, and whole-body scans, as measured with a radiation detector. Those values served as the basis for evaluating whole-body radiopharmaceutical clearance, as well as the risk for the exposure of others to radiation, depending on the time elapsed since administration of the radiopharmaceutical. Results: The mean time to clearance of the radiopharmaceuticals administered, expressed as the effective half-life, ranged from 1.18 ± 0.30 h to 11.41 ± 0.02 h, and the mean maximum cumulative radiation dose at 1.0 m from the patients was 149.74 ± 56.72 µSv. Even at a distance of 0.5 m, the cumulative dose was found to be only half and one tenth of the limits established for exposure of the general public and family members/caregivers (1.0 mSv and 5.0 mSv per episode, respectively). Conclusion: Cumulative radiation doses emitted by patients immediately after diagnostic nuclear medicine procedures are considerably lower than the limits established by the International Commission on Radiological Protection and the International Atomic Energy Agency, and precautionary measures to avoid radiation exposure are therefore not required after such procedures.

Resumo Objetivo: O objetivo deste trabalho foi levantar o potencial de dose de radiação emitida por pacientes em procedimentos diagnósticos, visando a estabelecer cuidados de radioproteção mais otimizados. Materiais e Métodos: Taxas de dose de radiação emitidas por 175 pacientes administrados com os radionuclídeos 99mTc, 131I e 18F para cintilografias óssea, renal, cardíaca, cerebral e corpo inteiro, foram mensuradas com um detector de radiação, servindo para avaliar o clareamento do radiofármaco no organismo e risco de exposição após administração dos radiofármacos. Resultados: O clareamento, representado pela meia-vida efetiva, variou de 1,18 ± 0,30 h até 11,41 ± 0,02 h e a dose de radiação máxima acumulada oferecida pelos pacientes a 1,0 m foi de 149,74 ± 56,72 µSv. Mesmo para distâncias de 0,5 m, as doses estimadas foram, respectivamente, duas e dez vezes inferiores ao nível de restrição para o público geral (1,0 mSv) e exposição médica (5,0 mSv/episódio). Conclusão: Doses de radiação oferecidas por pacientes em procedimentos diagnósticos são inferiores aos níveis de restrição recomendados pela International Commission on Radiological Protection e International Atomic Energy Agency, e assim, cuidados de radioproteção são geralmente desnecessários.

RESUMO

SUMMARY OBJECTIVE: This study aimed to determine the role of magnetic resonance imaging in minimizing radiation exposure, especially in the follow-up of pulmonary nodules. METHODS: Patients who applied to our hospital between April 2013 and August 2018 for various reasons and had lung-mediastinal dynamic magnetic resonance imaging and thoracic computed tomography were included in the study. A total of 194 patients were included in the study, involving 84 females and 110 males. Scanning of the nodules was done retrospectively. This study was conducted by two readers: a thoracic radiologist with 15 years of experience and a nonspecific radiologist with 4 years of experience. Evaluations were made using the double-blind method. RESULTS: Of the 194 patients, 84 (43.3%) were female and 110 (56.7%) were male. For the first reader, 135 (69.5%) nodules were detected in postcontrast T1 vibe images, 130 (67%) in T2 fast spin echo, 128 (66%) in precontrast T1 vibe, and 98 (50.5%) in T2 turbo inversion recovery magnitude sequence. For the second reader, 133 (68%) nodules were detected in postcontrast T1 vibe images, 120 (61.9%) in T2 fast spin echo, 122 (62.9%) in precontrast T1 vibe, and 99 (51%) in T2 turbo inversion recovery magnitude sequence. Capability levels were examined in detecting nodules between the first and second readers, and the ratios were reached at 0.92 in T2 fast spin echo, 0.81 in postcontrast T1 vibe images, 0.93 in precontrast T1 vibe, and 0.96 in T2 turbo inversion recovery magnitude sequence. CONCLUSION: In this study of detecting pulmonary nodules by magnetic resonance imaging, which we performed with two different readers, one of whom was an experienced thoracic radiologist, both readers found the highest detection rate in the postcontrast T1 vibe sequence.