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The aim of this study was to estimate radiation doses to patients undergoing standard radiographic examinations using Computed Radiography (CR) and Direct Digital Radiography (DDR) in two hospitals within Hamad Medical Corporation (HMC) in Qatar, and compare the results with regional and international Diagnostic Reference Levels (DRLs). Data on 3391 patients were recorded from different X-ray rooms in HMC hospitals. Entrance Skin Dose (ESD) was measured for 1046 patients for the most five common X-ray examinations (a total of 7 projections) namely: Skull, Chest, Abdomen, Lumbar Spine and Pelvis. Exposure factors such as kV, mAs and Focal to Skin Distance (FSD) were recorded for each patient. Tube Output was measured for a range of selected kV values. ESD for each individual patient was calculated using the tube output and the technical exposure factors for each examination. The ESD values were compared with some international DRLs for all types of examinations. HMC patient demographic data evaluated from this study were: average age of 39 years, average weight of 60-80 kg and mean height of 165 cm. The most procedure performed during the time of this study was chest PA (52%), and the least procedure performed was skull AP/LAT (1%) examination. The mean ESD values found to be generally lower than the published values. With exception of abdomen examinations at Hamad General Hospital (HGH), mean ESD values were found to be within the established IAEA (DRL). The mean ESD values at HGH were found to be much higher than that at Al Khor Hospital (AKH) for abdomen, Lumbar spine AP, Lumbar Spine LAT and pelvis, but generally lower than the published values.
ABSTRACT
Background: Radiation protection in paediatric radiology requires special attention than in adult because children are more sensitive to radiation and at higher risk. This risk is explained by the longer life expectancy in children which allows for harmful effects of radiation to manifest and their developing organs and tissues being more sensitive to radiation. Hence, the need for determination of appropriate radiation dose for paediatric patients. Aims: To estimate entrance skin dose (ESD) received by paediatric patients during diagnostic x-ray examinations. Materials and Methods: A total of 253 paediatric patients undergoing various x-ray examinations between June 2011 and December, 2012 in a teaching hospital in the South West Nigeria were considered in this study. This hospital has no dedicated x-ray unit for paediatric radiology. The ESD received during x-ray examination was calculated using mathematical formula that incorporated the use of x-ray beam output and exposure parameters selected for the examination. Correlation coefficient (r) analysis was used to test the relationship between ESD, patient size (age and weight) and exposure parameters (kVp, mAs). Results: The ESD and ED received by paediatric patients from all the x-ray examinations considered in this study ranged from 10.29 ± 3.80 - 880.04 ± 89.44 μGy and 1.44 ± 0.53 - 66.74 ± 30.84 μSv respectively. The correlation coefficient analysis at 0.01 level of significant showed that there is a correlation between patient dose and exposure factors but there is no correlation between ESD, age and weight of patients. Conclusion: The ESD received by paediatric patients is higher than the internationally recommended reference dose. This is attributed to lack of dedicated x-ray unit and personnel for paediatric radiology.
ABSTRACT
OBJETIVO: O objetivo do presente trabalho foi avaliar a influência da dependência energética de materiais termoluminescentes na determinação da dose na entrada da pele de pacientes submetidos a exames radiográficos (radiologia geral, mamografia e radiologia odontológica). MATERIAIS E MÉTODOS: Três diferentes materiais termoluminescentes foram utilizados: LiF:Mg,Ti, LiF:Mg,Cu,P e CaSO4:Dy. Estes materiais foram expostos a fontes padronizadas de radiação X e gama, e a feixes clínicos de raios X. RESULTADOS: As curvas de calibração e de dependência energética foram obtidas. Todos os materiais apresentaram resposta linear em função do kerma no ar. Com relação à dependência energética, as amostras de CaSO4:Dy e LiF:Mg,Ti mostraram maior variação da resposta termoluminescente em função da energia efetiva do feixe de radiação. CONCLUSÃO: Os materiais testados mostraram desempenho adequado para a detecção da radiação X em feixes padronizados e clínicos. Embora as amostras de CaSO4:Dy e LiF:Mg,Ti apresentem dependência energética significativa no intervalo de energia considerado, este materiais podem ser utilizados para medição da dose de entrada na pele se fatores de correção apropriados forem utilizados.
OBJECTIVE: This study was aimed at evaluating the influence of the energy dependence of thermoluminescent materials on the determination of entrance skin dose in patients submitted to conventional radiographic studies (general radiology, mammography and dental radiology). MATERIALS AND METHODS: Three different thermoluminescent materials were utilized: LiF:Mg,Ti, LiF:Mg,Cu,P and CaSO4:Dy. These materials were exposed to standardized sources of X and gamma radiation and clinical X-ray beams. RESULTS: Calibration and energy dependence curves were obtained. All the materials showed a linear response as a function of the air kerma. As far as energy dependence is concerned, the CaSO4:Dy and LiF:Mg,Ti samples showed the greatest variation on thermoluminescent responses as a function of the effective radiation beam. CONCLUSION: The tested materials showed an appropriate performance for detecting X radiation on standard and clinical X-ray beams. Although CaSO4:Dy and LiF:Mg,Ti samples present a significant energy dependence in the considered energy range, these materials can be utilized for measuring entrance skin doses, provided appropriate correction factors are applied.
Subject(s)
Humans , Radiation Protection , Radiation, Ionizing , Radiation Dosimeters , Thermoluminescent Dosimetry , RadiometryABSTRACT
OBJECTIVE: The aim of this work was to determine the radiation dose received by infants from radiographic exposure and the contribution from scatter radiation due to radiographic exposure of other infants in the same room. MATERIALS AND METHODS: We retrospectively evaluated the entrance skin doses (ESDs) and effective doses of 23 infants with a gestational age as low as 28 weeks. ESDs were determined from tube output measurements (ESD(TO)) (n = 23) and from the use of thermoluminescent dosimetry (ESD(TLD)) (n = 16). Scattered radiation was evaluated using a 5 cm Perspex phantom. Effective doses were estimated from ESD(TO) by Monte Carlo computed software and radiation risks were estimated from the effective dose. ESD(TO) and ESD(TLD) were correlated using linear regression analysis. RESULTS: The mean ESD(TO) for the chest and abdomen were 67 micro Gy and 65 micro Gy per procedure, respectively. The mean ESD(TLD) per radiograph was 70 micro Gy. The measured scattered radiation range at a 2 m distance from the neonatal intensive care unit (NICU) was (11-17 micro Gy[corrected to 11-17 nGy]) per radiograph. Mean effective doses were 16 and 27 micro Sv per procedure for the chest and abdomen, respectively. ESD(TLD) was well correlated with ESD(TO) obtained from the total chest and abdomen radiographs for each infant (R2 = 0.86). The radiation risks for childhood cancer estimated from the effective dose were 0.4 x 10(-6) to 2 x 10(-6) and 0.6 x 10(-6) to 2.9 x 10(-6) for chest and abdomen radiographs, respectively. CONCLUSION: The results of our study show that neonates received acceptable doses from common radiological examinations. Although the contribution of scatter radiation to the neonatal dose is low, considering the sensitivity of the neonates to radiation, further protective action was performed by increasing the distance of the infants from each other.