Clinical Assessment of Radiological Evaluation of Entrance Surface Dose in Neonates and Pediatric Patients across Dhaka, Bangladesh
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The research purposed to estimate Entrance Surface Dose (ESD) in pediatric patients receiving chest X-ray and CT scanning, examining differences in doses among various age subgroups. A retrospective cross-sectional study was conducted on 197 pediatric patients aged between 1 day to 12 years who were all derived from the radiology department. The present research included information collected between 23rd September, 2024, to 23rd December, 2024. Clinical indications, demographics of patients, and parameters of exposure (mAs, kVp) were all recorded, with Entrance Skin Dose (ESD) being calculated using Chuan and Tsai formula. Statistical analysis was conducted using Excel and SPSS. ESD values ranged from 0.17 mGy to 12.11 mGy, with wide variations by age and exposure factors. Newborns had lower ESD values than those of older children, matching the range of imaging requirements. The average ESD was calculated at 1.83 mGy, greater than in some but in agreement with other studies, demonstrating a high level of heterogeneity in pediatric radiation doses. This refers to the need for optimized radiological procedures to minimize unnecessary radiation exposure. Findings are consistent with the literature, confirming that ESD is influenced by patient age and technical factors. However, the comparatively higher average ESD in the current study refers to the need for continuous evaluation and optimization of imaging protocols. Ensuring patient safety requires continual monitoring of doses, correct setting of exposures, and advances in radiological technology. The study highlights the need to balance diagnostic quality and radiation safety, recommending ongoing assessment and optimization of pediatric imaging protocols to reduce radiation exposure without sacrificing diagnostic accuracy.
X-ray examinations are a well-established diagnostic tool, providing undeniable benefits to patients despite the inherent risks due to the ionizing nature of X-rays. Overexposure to X-rays can lead to harmful effects, making it crucial to apply radiation protection principles in medical diagnostics involving X-ray procedures. All X-ray exposures should be both justified and optimized in terms of balancing the benefits against the potential risks (Ciraj-Bjelac et al., 2003; Clarke, R. et al., 2005; Ciraj, O et al., 2005). X-rays transfer a specific amount of energy to biological systems as they penetrate tissues, which can pose risks to the cells that make up these systems (Alghoul A et al., 2016). Concerns about higher levels of diagnostic X-ray exposure have increased, as reflected in the recommendations of the International Commission on Radiological Protection (ICRP) (ICRP et al., 2000; Bochud, F. O et al., 2002; Alghoul, A. et al., 2017; Hayle et al., 2020).
These recommendations urge countries to implement measures to restrict radiation doses for patients undergoing X-ray examinations across radiographic centers and hospital radiology departments. A key factor in radiation protection is the patients dose, often quantified through the entrance surface dose (ESD), which represents the absorbed dose at the point where the X-ray beam intersects the patients surface, including backscatter. ESD is a fundamental metric for assessing patient dose and optimizing radiation exposure. It also serves as a crucial benchmark for comparing international reference dose levels, playing a vital role in radiation protection (Zoetelief, J. et al., 2002; Nawreen et al., 2024). There are several methods to determine ESD, with the most common being either direct measurements using Thermoluminescent Dosimeters (TLDs) placed on the patients skin or indirect calculations based on the X-ray machines output. ESD can also be determined using phantom measurements and data from the patients examination (Jornet N et al., 2013; Gaetabo Compagnone et al., 2005; Shabon M. et al., 2013). However, using TLDs can be time-consuming and requires specialized equipment that may not be available in all radiographic centers. Alternatively, measuring ESD with ionization chambers involves using conversion factors to translate the chambers readings into absorbed dose, which can be a more complex process (Li, L. B et al., 2001). Due to the challenges associated with TLDs and ionization chambers, this study employed a mathematical approach to estimate ESD. The research aimed to estimate ESD for patients exposed to diagnostic X-rays at medical radiographic centers, using the Chuan and Tsai formula to calculate ESD for multiple X-ray examinations. The results were then compared with international reference ESD values reported in the literature.
Objective of the study
General Objective
Specific Objectives
This study was a cross-sectional, retrospective review focused on evaluating the Entrance Surface Dose (ESD) in pediatric patients aged 1 day to 12 years who underwent X-ray and CT scan investigations at a selected hospital. A total of 197 patients were purposively chosen based on inclusion criteria from the radiology department database, with data collected between September 23, 2024, and December 23, 2024. The study protocol was approved by Bangladesh University of Health Sciences, Dhaka, Bangladesh. For each pediatric patient, information such as age, gender, clinical indications, type of imaging modality, exposure settings (including peak tube voltage or kVp, exposure current and time product or mAs, exposure time in milliseconds), focus-to-surface distance (FSD), minimum inherent filtration, and details of the examinations and radiological findings were recorded. This data was captured at the time of each examination.
The equipment used for imaging met the DHHS requirements, with a minimum inherent filtration of 2 mm Aluminum equivalent for the portable X-ray machine at 125 kV, and 0.5 mm Aluminum for the departments X-ray machine at 70 kV, capable of ratings up to 150 kVp. The Spearmans correlation test was performed to assess any relationship between patient age and radiological findings, with statistical significance determined at p<0.05. The Chuan and Tsai formula was used to calculate the ESD for each patient visiting the radiology center. The sample consisted primarily of pediatric males and females. This formula is given as follows:
ESD (mGy)=c (kVp/FSD)2 ×(mAs/(mm.Al))
In this study, kVp refers to the peak tube voltage of the X-ray, while mAs represents the exposure value, calculated by multiplying the tubes current by the exposure time. FSD, or Focus to Skin Distance, is the measured distance between the X-ray tube and the area of the patients body being exposed. The mmAl indicates the minimum inherent filtration in terms of Aluminum equivalent, and the constant c is equal to 0.2775. The collected data were processed using Microsoft Excel 2013 and the Statistical Package for Social Sciences (SPSS) version 20 (IBM Corporation, Chicago, IL, USA). The analysis followed the studys objectives, utilizing both descriptive statistics (such as frequency tables, charts, and percentages) and inferential statistics. Ethical approval was granted by the Human Research and Ethics Committees of the study centers. All patient information was handled with strict confidentiality and used solely for the purpose of this research.
This study was conducted at a radiographic center in Dhaka city, and the results are presented in the tables below. The data includes information on patients gender, age, type of examination, frequency, percentage, thickness of filtration (minimum inherent Aluminum filtration), kVp, mAs, Focus to Skin Distance (FSD), radiological findings, and the Entrance Surface Dose (ESD) for all chest X-ray examinations. The results also cover medical procedures for pediatric patients aged from 1 day to 12 years. Table 1 through 9 show the estimated ESD values and corresponding radiological findings for each examination.
Table 1: ESD (mGy) of Chest Examination of Newborn- ages 0 day to 28 days.
N.B.: Sex: M- Male and F- Female; Age: D- Day, M- Month, and Y- Year; Thickness of Filtration: Portable machine- mm Al/125 kVp and Departments machine- mm Al/70 kVp
Table 1 includes the chest examination records of 197 pediatric patients. Among them, 25 were newborns, with 11 males and 14 females. This table highlights the exposure settings used to estimate the ESD for patients undergoing chest examinations. The peak tube voltage (kVp) ranged from a minimum of 48 kVp to a maximum of 60 kVp. The exposure values (mAs) varied from a minimum of 6.4 mAs to a maximum of 32.37 mAs. The Entrance Surface Dose (ESD) values recorded ranged from 0.29 mGy at the lowest to 2.61 mGy at the highest, all for chest examinations.
Table 2: ESD (mGy) of Infant- ages 29 day to 1 year.
N.B.: Sex: M- Male and F- Female; Age: D- Day, M- Month, and Y- Year; Thickness of Filtration: Portable machine- mm Al/125kVp and Departments machine- mm Al/70kV.
Table 2 presents chest examination records of 197 pediatric patients, including 26 infants. Of these, 16 were male and 10 were female. The table outlines the exposure settings used to estimate the ESD for chest examinations. The peak tube voltage (kVp) ranged from a minimum of 48 kVp to a maximum of 75 kVp. The exposure values (mAs) varied from a minimum of 5.3 mAs to a maximum of 20.08 mAs. The recorded Entrance Surface Dose (ESD) values ranged from 0.21 mGy to a maximum of 12.96 mGy for chest examinations in this age group.
Table 3: ESD (mGy) of Toddler- ages upto 1 year to 2 years.
N.B.: Sex: M- Male and F- Female; Age: D- Day, M- Month, and Y- Year; Thickness of Filtration: Portable machine- mm Al/125 kVp and Departments machine- mm Al/70kVp.
Table 3 contains chest examination records for 197 pediatric patients, including 22 toddlers. Of these, 12 were male and 10 were female. This table outlines the exposure settings used to estimate ESD for chest examinations. The peak tube voltage (kVp) ranged from 50 kVp to 60 kVp. The exposure values (mAs) varied from a minimum of 6.4 mAs to a maximum of 181.6 mAs. The Entrance Surface Dose (ESD) values recorded ranged from 0.17 mGy to 12.11 mGy for chest examinations in this age group.
Table 4: ESD (mGy) of Preschooler- ages upto 2 years to 6 years.
This study provides a comprehensive evaluation of Entrance Surface Dose (ESD) values for chest examinations in pediatric patients across various age groups in a radiographic center in Dhaka. The findings reveal notable variations in exposure settings and ESD values when compared to existing literature. Our data, summarized in Table 1-5, show a wide range of exposure settings and ESD values. For newborns, the peak tube voltage (kVp) ranged from 48 to 60 kVp, with exposure values (mAs) from 6.4 to 32.37 mAs, resulting in ESDs from 0.29 to 2.61 mGy. Infants had kVp values between 48 and 75 kVp and mAs values ranging from 5.3 to 20.08, with ESDs varying from 0.21 to 12.96 mGy. For toddlers, kVp ranged from 50 to 60 kVp and mAs from 6.4 to 181.6, with ESDs from 0.17 to 12.11 mGy. Preschoolers and school-aged children showed similar trends with kVp from 50 to 75 kVp and exposure values ranging broadly, resulting in ESDs from 0.17 to 11.28 mGy and 0.21 to 9.11 mGy, respectively.
These results align with the notion that ESD values and exposure settings vary significantly with age and body size. The higher ESD values observed in our study, particularly for infants and toddlers, are consistent with findings from other studies which report similar variations in ESD based on age and imaging parameters. When comparing the mean ESD values from this study with those reported in the literature, notable differences emerge. Our study found a mean ESD of 1.83 mGy across all age groups (Table 6). In contrast, previous studies have reported lower average ESD values: 0.73 mGy (Yousif A et al., 2016) (Tamboul, J. Y et al., 2014), 0.18 mGy, 0.07 mGy, 0.1 mGy, 0.35 mGy, and a higher value of 7.43 mGy . The considerable range of ESD values observed across studies highlights the impact of differing exposure settings, imaging technologies, and patient demographics. Table 7 compares our studys average kVp, mAs, FSD, and ESD with those reported in the literature. We found average kVp values of 58.79, average mAs of 21.82, and an average FSD of 102 cm, resulting in an average ESD of 1.83 mGy. These values contrast with other studies, which reported an average kVp of 60 (Akhdar, H. F et al., 2007), an average mAs of 1.5 (Alghoul A, Abdalla MM et al., 2017), an average FSD of 110 cm, and an average ESD of 0.23 mGy. The differences in kVp, mAs, and FSD likely contribute to the variability in ESD values. The findings underscore the importance of optimizing radiation doses in pediatric imaging to minimize exposure while ensuring diagnostic efficacy. The observed variations in ESD values indicate a need for consistent application of radiation protection principles and adherence to dose optimization guidelines across radiographic centers. The higher ESD values observed in our study compared to others may reflect differences in imaging protocols or equipment used. This suggests that implementing standardized protocols and regularly reviewing imaging practices could help reduce unnecessary radiation exposure and align with international recommendations for dose limits.
Limitation
In this study, we assessed the Entrance Surface Dose (ESD) for pediatric patients undergoing chest X-ray examinations, revealing a significant range in ESD values across different age groups and imaging settings. The observed mean ESD of 1.83 mGy was notably higher compared to values reported in the literature. The variability in ESD can be attributed to differences in imaging parameters such as kVp and mAs, as well as equipment and procedural differences. To reduce radiation exposure in pediatric patients, it is crucial to adhere to optimized imaging protocols and to continuously evaluate and adjust exposure settings based on patient age and clinical indications. Standardizing imaging practices and employing dose-reduction strategies can help minimize radiation risks while ensuring diagnostic quality. Future research should aim to refine these protocols and explore advanced technologies to further enhance patient safety.
S.A.; N.T.N.; and M.A.O.: contributed to the development of the research framework and methodology, as well as manuscript composition, data assessment, questioning, and visual depiction. T.P.: provided guidance and supervision throughout the course of this article. In addition, N.T.N.; and M.A.O.: were mainly accountable for manuscript completion, thorough review and editing, and aiding in data management, funding acquisition, and formal analysis. All the authors have read and approved the manuscripts final version for publication.
We would like to thank the Department of Radiology and Imaging Technology, Bangladesh University of Health Sciences, Department of Biomedical Engineering & Medical Physics, Bangladesh University of Health Sciences, Dhaka, Bangladesh and the Department of Computer Science and Engineering, Ahsanullah University of Science and Technology (AUST), with heartfelt gratitude for their complete support and cooperation. The support and cooperation from these departments were very significant in making this study a success, and we are deeply thankful for that.
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Academic Editor
Dr. Toansakul Tony Santiboon, Professor, Curtin University of Technology, Bentley, Australia
Ahmmed S, Neha NT, Obayda MA, and Parvin T. (2025). Clinical assessment of radiological evaluation of entrance surface dose in neonates and pediatric patients across Dhaka, Bangladesh. Aust. J. Eng. Innov. Technol., 7(2), 169-179. https://doi.org/10.34104/ajeit025.01690179
