Diagnostic Reference Level of Radiation Dose and Image Quality among Paediatric CT Examinations in A Tertiary Hospital in Malaysia

Evaluating Radiation Exposures and Establishments of National Diagnostic Reference Levels for Patients Undergoing Chest Computed Tomography Examinations in Ethiopia

Computed tomography is invaluable for both diagnostic and therapeutic purposes. The common challenge is using an optimized CT technique to produce qualified images while giving patients the least amount of radiation possible. The objective of the study was to determine the national DRL values for adult patients undergoing chest computed tomography examination in Ethiopia. This was a retrospective cross-sectional study conducted in twenty three (23) different CT scan facilities on 801 patients who underwent chest computed tomography examinations in Ethiopia, in which participants were recruited by systematic random sampling. Data processing in this study was carried out with a quantitative analysis technique, namely descriptive statistics. The study variables were CTDI volume and dose length product (DLP) for the radiation doses for chest CT examinations. The age range for all adult patients was above 15 years old. Their body weights were in the range of 40-80 kg. The third quartile of the distributions of the median values of these variables was used to establish chest national diagnostic reference levels. The national DRL was compared with DRLs of other countries. Microsoft Excel form and SPSS software version 26 were used to collect and analyze survey data. A total of 801 patients were examined with an average age of 48.96 years. The patients were examined with their radiological department protocol using multislice CT (MSCT) from different manufacturers. For adult chest computed tomography examinations, the calculated dose length product and computed tomography dose index third quartile values that were used as national diagnostic reference levels were 512.9 mGy cm and 10.165 mGy, respectively.Even though the computed tomography dose index volume of the current study is less than that of all African and non-African countries selected for comparison, the proposed national DLP of the current study values were intermediate and substantially higher than those reported in similar studies from African and non-African countries, respectively. It is plausible to believe that the number of sequences, scan parameters, and automatic exposure control all contribute to better optimization and increased scanner dose efficiency for non-African countries, which is the cause of this discrepancy.

Estimation of effective dose and risk of exposure-induced cancer death, and diagnostic reference level for CT scans in Tabriz, Iran

This study aimed to estimate the effective dose and the risk of exposure-induced cancer death (REID), as well as to establish diagnostic reference levels (DRLs) for common CT examinations conducted in Tabriz, Iran. The investigation included adult patients undergoing abdomen-pelvis, brain, neck, sinus, and chest CT scans. Patient data, exposure parameters, and radiation dose metrics, such as volume CT dose index (CTDIvol) and dose length product (DLP), were collected and analyzed. The results showed significant variations in radiation dose across different centers for the CT scans. The average effective doses for the different CT scans were 5.65, 1.08, 1.40, 0.46, and 3.68 mSv for abdomen-pelvis, brain, neck, sinus, and chest scans, respectively. The REID values ranged from 14 per million (for sinus scans) to 196 per million (for abdomen-pelvis scans). Additionally, the DRL values for CTDIvol were 11.03 (for abdomen-pelvis), 59.52 (for brain), 8.33 (for neck), 17.05 (for sinus), and 7.83 mGy (for chest). Our results showed that most of the investigated CT scans had lower effective doses compared to the literature and the REIDs were estimated to be low. Minimizing radiation risk can be achieved by reducing CT exams and keeping doses as low as reasonably achievable. The local DRLs from this study were comparable to previous reports and can serve as benchmarks for setting national and international DRLs, helping healthcare facilities optimize radiation practices and improve patient safety in diagnostic imaging.

Techniques and Strategies to Minimize Radiation Exposure in Pediatric Computed Tomography (CT) Abdominal Examinations: A Review

As children are more vulnerable to radiation-induced cancers and have longer life expectancies, it is essential to implement strict radiation protection measures in pediatric imaging. This study aimed to review radiation dose-minimizing measures in pediatric abdominal computed tomography (CT) examinations. A systematic search across various databases, including Web of Science, PubMed, SpringerLink, ScienceDirect, and Google Scholar, yielded a total of 7,314 articles. The search used keywords that aligned with the objectives of the study. This study included 77 publications after applying the criteria for inclusion and exclusion. We carefully reviewed these selected articles for compliance with the inclusion criteria and excluded them if they did not meet the specified criteria. Only 12 articles fulfilled the strict criteria. An in-depth review of 12 selected articles demonstrated the radiation dose reduction techniques and strategies, which include prefiltering and post-processing algorithms, careful adjustment of exposure parameters such as tube voltage (kVp) and current (mAs), and the establishment of diagnostic reference levels (DRL). Reduction of radiation exposure in pediatric CT imaging demands multifaceted approaches. To reduce the ionizing radiation dose while still obtaining high-quality diagnostic images, healthcare practitioners should adhere to DRL, adjust exposure factors, implement prefiltration, employ AI, and use post-processing algorithms.

Age-based diagnostic reference levels and achievable doses for paediatric CT: a survey in Shanghai, China

Computed tomography (CT) is extensively utilised in medical diagnostics due to its notable radiographic superiority. However, the cancer risk associated with CT examinations, particularly in children, is of significant concern. The assessment of cancer risk relies on the radiation dose to examinees. Diagnostic reference levels (DRLs) and achievable doses (ADs) were used to assess the level of radiation dose in CT examinations widely. Although the national DRLs of paediatric CT have been explored in China, few local DRLs at the city level have been assessed. To set up the local DRLs and ADs of paediatric CT, we investigated the radiation dose level for paediatric CT in Shanghai. In this survey, a total of 3061 paediatric CT examinations underwent in Shanghai in 2022 were selected by stratified sampling, and the dose levels in terms of volume CT dose index (CTDIvol) and the dose-length product (DLP) were analysed by 4 age groups. The DRLs and ADs were set at the 75th and 50th percentile of the distribution and compared with the previous studies at home and abroad. The survey results revealed that, for head scan, the DRLs of CTDIvolwere from 25 to 46 mGy, and the levels of DLP were from 340 to 663 mGy·cm. For chest, the DRLs of CTDIvolwere from 2.2 to 8.3 mGy, and the levels of DLP were from 42 to 223 mGy·cm. For abdomen, the DRLs of CTDIvolwere from 6.3 to 16 mGy, and the levels of DLP were from 181 to 557 mGy·cm. The ADs were about 60% lower than their corresponding DRLs. The levels of radiation doses in children-based hospitals were higher than those in other medical institutions (P< 0.001). In conclusion, there was still potential for reducing radiation dose of paediatric CT, emphasising the urgent need for optimising paediatric CT dose in Shanghai.

Assessment of diagnostic reference levels for paediatric cardiac computed tomography in accordance with European guidelines

Recently, paediatric cardiac computed tomography (CCT) has caused concerns that diagnostic image quality and dose reduction may require further improvement. Consequently, this study aimed to establish institutional (local) diagnostic reference levels (LDRLs) for CCT for paediatric patients, and assess the impact of tube voltage on proposed DRLs in terms of the volume computed tomography index (CTDIvol) and dose length product (DLP). In addition, effective doses (EDs) of exposure were estimated. A population of 453 infants, whose mass and age were less than 12 kg and 2 years, respectively, were considered from January 2018 to August 2021. Based on previous studies, this number of patients was considered to be sufficient for establishing LDRLs. A group of 245 patients underwent CCT examinations at 70 kVp tube voltage with an average scan range of 23.4 cm. Another set of 208 patients underwent CCT examinations at 100 kVp tube voltage with an average scan range of 15.8 cm. The observed CTDI_vol and DLP values were 2.8 mGy and 54.8 mGy.cm, respectively. The mean effective dose (ED) was 1.2 mSv. It is concluded that provisional establishment and use of DRLs for cardiac computed tomography in children are crucial, and further research is needed to develop regional and international DRLs.

Establishment of local diagnostic reference levels for paediatric abdominal-pelvis and Chest-abdominal-pelvis computed tomography in Morocco: suggests the need for improved optimization efforts

The purpose of the current study was to derive the local diagnostic reference levels (LDRLs) for paediatric abdominal-pelvis (AP) and chest-abdominal-pelvis (CAP) computed tomography in Morocco. The data were gathered retrospectively from two hospitals for 6 months. The LDRLs were defined by volume CT dose index (CTDIvol), dose-length product (DLP) per sequence, DLP per procedure and size-specific dose estimates (SSDE). The SSDE assessment was based on the effective diameters of patients scanned. A total of 630 CT examinations were collected involving 324 AP and 306 CAP scans. The proposed LDRLs for AP, in terms of CTDIvol (mGy), were 6.9, 8.5, 8.5 and 8.5 for < 1, 1 to < 5, 5 to < 10 and 10 to < 15 y age groups, respectively. In terms of DLP (mGy.cm) per procedure, they were 436.3, 534.5, 687.9 and 961.7. In terms of SSDE (mGy), thet were 16.73, 16.83, 17.5 and 15.8 for < 1, 1 to < 5, 5 to < 10 and 10 to < 15 y, respectively. The corresponding LDRLs for CAP, in terms of CTDIvol (mGy), were 7.3, 7.3, 7.3 and 10.35. In terms of DLP (mGy.cm) per procedure, they were 531, 622.5, 705 and 936. In terms of SSDE (mGy), they were 16.22, 15.05, 14.47 and 15.2, respectively, for the four age groups. The derived dose levels were mostly higher than those found in other studies, which demonstrates the need for dose optimization and paediatric protocol standardization as well as the timeliness of the intent to establish not only local DRLs but national ones in the near future.

Establishment of national diagnostic dose reference levels (DRLs) for routine computed tomography examinations in Jordan

Background: Dose reference levels (DRLs) are used as indicators as well as guidance for dose optimization and to ensure justification of appropriate dose for a given clinical indication. The main aims of this study were to establish local DRLs for each CT imaging protocol as a reference point to evaluate the radiation dose indices and to compare our DRLs with those established in other countries and against the internationally reported guidelines.

Materials and methods: 2000 CT dose reports of different adult imaging protocols from January 2021 until April 2022 were collected retrospectively at different hospitals in Jordan. Data were collected from CT scans that were performed using different types and models of CT scanners and included four adult non-enhanced, helical CT imaging protocols; Head, Chest, Abdomen-Pelvis, and Chest-Abdomen-Pelvis.

Results: The average doses of CTDIvol, DLP, and effective dose were (65.11 mGy, 1232.71 mGy·cm, 2.83 mSv) for the head scan, (16.6 mGy, 586.6 mGy·cm, 8.21 mSv) for the chest scan, (17.91 mGy, 929.9 mGy·cm, 13.9 mSv) for the abdomen-pelvis scan, and (19.3 mGy, 1152 mGy·cm, 17.25 mSv) for the chest-abdomen-pelvis scan. In comparison with results from different international studies, DLP values measured in the present study were lower for the chest-abdomen-pelvis and abdomen-pelvis CT scans, and higher for the head CT and chest CT scans.

Conclusions: It is very important that each country establishes its own DRLs and compares them with those reported by other countries, especially the developed ones. It is also important that these levels are regularly updated.

Establishment of local diagnostic reference levels for common adult CT examinations: a multicenter survey in Addis Ababa

BACKGROUND

In medical imaging, a computed tomography (CT) scanner is a major source of ionizing radiation. All medical radiation exposures should be justified and optimized to meet the clinical diagnosis. Thus, to avoid unnecessary radiation doses for patients, diagnostic reference levels (DRLs) have been used. The DRLs are used to identify unusually high radiation doses during CT procedures, which are not appropriate for the clinical diagnosis. It has been successfully implemented in Europe, Canada, Australia, the United States, several industrialized countries, and a few underdeveloped countries. The present study aimed to establish DRLs for the head, chest, and abdominopelvic (AP) CT procedures in Addis Ababa, Ethiopia.

METHODS

A pilot study identified the most frequent CT examinations in the city. At the time of the pilot, eighteen CT scan facilities were identified as having functioning CT scanners. Then, on nine CT facilities (50% of functional CT scanners), a prospective analysis of volume CT dose index (CTDI_vol) and dose length product (DLP) was performed. We collected data for 838 adult patients' head, chest, and AP CT examinations. SPSS version 25 was used to compute the median values of the DLP and CTDI_vol dose indicators. The rounded 75th percentile of CTDI_vol and DLP median values were used to define the DRLs. The results are compared to DRL data from the local, regional, and international levels.

RESULT

The proposed DRLs using CTDI_vol (mGy) are 53, 13, and 16 for the head, chest, and AP examinations respectively, while the DLP (mGy.cm) for the respective examinations were 1210, 635, and 822 mGy.cm.

CONCLUSION

Baseline CT DRLs figures for the most frequently performed in Addis Ababa were provided. The discrepancies in dose between CT facilities and as well as between identical scanners suggests a large potential for dose optimization of examinations. This can be actually achieved through appropriate training of CT technologists and continuous dose audits.

Evaluation of image quality, organ doses, effective dose, and cancer risk from pediatric brain CT scans

PURPOSE

The present study was conducted to assess organ doses, effective dose, and image quality, and to estimate the risk of exposure-induced cancer death (REID) in pediatric brain computed tomography examinations.

METHODS

This investigation was performed on 179 pediatric patients (99 men and 80 women) under 12 years old who underwent non-contrast brain CT scans. Patients were classified into four age groups of ≤ 1, 2-5, 6-9, and 10-12 years old. Organ doses and effective doses were calculated using the ImpactDose program. Cancer risk models presented in the BEIR VII report were used to estimate REID values. Image quality assessment in this study was performed by measuring image quality parameters such as noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR).

RESULTS

The highest organ dose in all age groups belonged to the brain. The mean REID values were 12.34 per 100,000 males and 16.77 per 100,000 females. REID values decreased with the increasing age of patients in both genders and were higher for female children than male children. The mean SNR of gray matter, SNR of white matter, and CNR were 11.04, 10.5, and 2.31, respectively.

CONCLUSIONS

According to the results of this study, brain CT scans in children are associated with an increased potential risk of cancer. Therefore, minimizing unnecessary radiation exposure in pediatric patients and using alternative imaging modalities are of particular importance. Moreover, optimizing the radiation parameters while maintaining the diagnostic image quality in children should be considered.

Estimation of radiation dose and establishment of local diagnostic reference levels for computed tomography of head in pediatric population

BACKGROUND

Pediatric population is more sensitive to the effects of radiation than adults. Establishing diagnostic reference level (DRL) is an efficient dose optimization technique implemented by many countries for reducing radiation dose during Computed Tomography (CT) examinations.

OBJECTIVES

To estimate radiation dose and establish a new local diagnostic reference level for CT head examination in the pediatric population.

MATERIALS AND METHODS

We prospectively recruited 143 pediatric patients referred for CT head examination with age ranging from 0-5 years old. All patients had undergone CT head examination using the standard pediatric head protocol. Volumetric CT dose index (CTDIvol) and dose length product (DLP) were recorded. The effective dose was first calculated. Then, 75th percentile of dose indices was calculated to establish DRLs.

RESULTS

DRLs in terms of CTDIvol and DLP are 23.84 mGy, 555.99 mGy.cm for patients <1 years old and 28.65 mGy, 794.99 mGy.cm for patients from 1-5 years old, respectively. Mean effective doses for <1 years old patients and 1-5 years old patients are 2.91 mSv and 2.78 mSv respectively.

CONCLUSION

The study concludes that DRL in terms of CTDIvol is lower but DRL in terms of DLP and the effective dose is higher compared to a few other studies which necessitate the need for dose 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.

Differences in radiation dose for computed tomography of the brain among pediatric patients at the emergency departments: an observational study

BACKGROUND

Computed tomography (CT) is associated with a risk of cancer development. Strategies to reduce radiation doses vary between centers. We compared radiation doses of CT brain studies between pediatric and general emergency departments (EDs), and determine the proportion studies performed within the reference levels recommended by the International Commission on Radiological Protection (ICRP).

METHODS

A retrospective review was carried out in a healthcare network consisting of one pediatric ED and three general hospital EDs. Pediatric patients less than 16 years old with CT brain studies performed between 1 January 2015 and 31 December 2018 were included. Information on demographic, diagnosis, volume-averaged computed-tomography dose index and dose length product (DLP) were collected. Effective dose was then calculated from DLP using conversion factors, termed k-coefficients which were derived using a 16 cm head CT dose phantom.

RESULTS

Four hundred and seventy-nine CT brain studies were performed - 379 (79.1%) at the pediatric ED. Seizure (149, 31.1%), head injury (147, 30.7%) and altered mental status (44, 9.2%) were the top three ED diagnoses. The median effective dose estimates were higher in general than pediatric EDs, particularly for those aged > 3 to ≤6 years old [1.57 mSv (IQR 1.42-1.79) versus 1.93 mSv (IQR 1.51-2.28), p = 0.047], > 6 to ≤10 years old [1.43 mSv (IQR 1.27-1.67) versus 1.94 mSv (IQR 1.61-2.59), p = 0.002) and > 10 years old (1.68 mSv (IQR 1.32-1.72) versus 2.03 mSv (IQR 1.58-2.88), p < 0.001). Overall, 233 (48.6%) and 13 (2.7%) studies were within the reference levels recommended by ICRP 60 and 103 respectively.

CONCLUSIONS

Radiation doses for CT brain studies were significantly higher at general EDs and less than half of the studies were within the reference levels recommended by ICRP. The development of diagnostic reference levels (DRLs) as a benchmark and clinical justification for performing CT studies can help reduce the radiation risks in the pediatric population.

Local Diagnostic Reference Levels for Paediatric Head CT Procedures

Background.

Patients, especially children, are exposed to substantially high doses of ionising radiation during computed tomography (CT) procedures. Children are several times more susceptible to ionising radiation than adults. Diagnostic reference levels (DRLs) are an important tool for monitoring and optimising patient radiation exposure from radiological procedures. The aim of this study is to estimate the ionising radiation exposure doses and set local DRLs for head CT examinations according to age and to compare local DRLs with national and European DRLs and with literature data in other countries.

Materials and methods.

Scan parameters of single-phase head CT examinations were collected. Patients were grouped by age in the following intervals: <1, 1−5, 5−10, 10−15 and 15−18 years. Local age-based DRLs set as the 3^rd quartile of the median dose-length product (DLP) were calculated. Literature analysis was performed on PubMed search engine on inclusion criteria: publication date 2015–2020, used keywords paediatric computed tomography, paediatric CT, diagnostic reference levels (DRLs). The 23 articles discussing paediatric DRLs were further analysed.

Results.

Data was collected from 194 paediatric head CT examinations performed in 2019. The median DLP values for head CT were 144.3, 233.7, 246.4, 288.9, 315.5 for <1, 1−5, 5−10, 10−15 and 15−18 years old groups. Estimated local DRLs for head CT examinations are 170, 300, 310, 320, 360 mGy*cm for <1, 1−5, 5−10, 10−15 and 15−18 years age groups respectively and 130, 210, 275, 320 mGy*cm for 0−3 months, 3 months−1 year, 1−6 years and ≥ 6 years age groups respectively.

Conclusions.

Results of this study showed that settled new local DRLs of head CT examinations were 2–4 times lower than national DRLs and about 2 times lower than European DRLs. Moreover, the study indicated that paediatric head CT doses are significantly lower in comparison with those indicated in the majority of published data from other hospitals over the last 6 years. Patient dose assessment and local DRLs establishment plays important role in future exposure optimisation.

Reducing the Breast Cancer Risk and Radiation Dose of Radiography for Scoliosis in Children: A Phantom Study

Full-spinal radiographs (FRs) are often the first choice of imaging modality in the investigation of scoliosis. However, FRs are strongly related to breast cancer occurrence due to multiple large-field radiographic examinations taken during childhood and adolescence, which may increase the risk for breast cancer in adulthood among women with scoliosis. The purpose of this study was to consider various technical parameters to reduce the patient radiation dose of FRs for scoliosis. To evaluate breast surface doses (BSDs) in FRs, radio photoluminescence dosimeters were placed in contact with a child phantom. Using the PC-based Monte Carlo (PMC) program for calculating patient doses in medical X-ray examinations, the breast organ dose (BOD) and the effective dose were calculated by performing Monte Carlo simulations using mathematical phantom models. The BSDs in the posteroanterior (PA) view were 0.15-0.34-fold those in the anteroposterior (AP) view. The effective dose in the PA view was 0.4-0.61-fold that in the AP view. BSD measurements were almost equivalent to the BODs obtained using PMC at all exposure settings. During FRs, the PA view without an anti-scatter grid significantly reduced the breast dose compared to the AP view with an anti-scatter grid.