PROPOSED NATIONAL DIAGNOSTIC REFERENCE LEVELS FOR STANDARD RADIOGRAPHIC X-RAY PROCEDURES IN SUDAN

Establishment and utilisation of national diagnostic reference level for adult computed tomography examinations in Ghana

The International Atomic Energy Agency, as part of the new regional project (RAF/9/059), recommend the establishment of diagnostic reference levels (DRLs) in Africa. In response to this recommendation, this project was designed to establish and utilise national DRLs of routine computed tomography (CT) examinations. These were done by estimating CT dose index and dose length product (DLP) from a minimum of 20 patient dose report of the most frequently used procedures using 75th percentile distribution of the median values. In all, 22 centres that formed 54% of all CT equipment in the country took part in this study. Additionally, a total of 2156 adult patients dose report were randomly selected, with a percentage distribution of 60, 12, 21 and 7% for head, chest, abdomen-pelvis and lumber spine, respectively. The established DRL for volume CT dose index were 60.0, 15.7, 20.5 and 23.8 mGy for head, chest, abdomen-pelvis and lumber spine, respectively. While the established DRL for DLP were 962.9, 1102.8, 1393.5 and 824.6 mGy-cm for head, chest, abdomen-pelvis, and lumber spine, respectively. These preliminary results were comparable with data from 16 other African countries, European Commission and the International Commission on Radiological Protection. Hence, this study would serve as a baseline for the establishment of a more generalised regional and national adult DRLs for Africa and other developing countries.

Entrance surface air kerma to patients during digital radiographic examinations in Tanzania

The aim of this study was to determine the entrance surface air kerma (ESAK) in adult patients during digital radiography and to evaluate the optimisation potential in five common X-ray examinations in Tanzania. Based on a sample of 240-610 patients, ESAK was estimated using X-ray tube output measurements, patient information and backscatter factors. The results show that the mean ESAK values were higher or comparable to data from the literature. The diagnostic reference values of ESAK for digital radiography were 0.31 mGy (chest PA), 4 mGy (lumbar spine AP), 5.4 mGy (lumbar spine LAT), 3.8 mGy (abdomen AP) and 2.4 mGy (pelvis AP). For computed radiography, the mean ESAK ranges were 0.44-0.57 mGy (thoracic AP), 3.59-3.72 mGy (lumbar spine AP), 6.16-6.35 mGy (lumbar spine LAT), 3.89-3.44 mGy (abdominal AP) and 2.92-3.47 mGy (pelvic AP). In conclusion, high ESAK variations show the potential for optimising protection in digital radiology.

Evaluation of patient doses for routine digital radiography procedures toward establishing an institutional diagnostic reference levels: A case study in Sri Lanka

The present study was conducted as part of a comprehensive work to establish National Diagnostic Reference Levels (NDRLs) in Sri Lanka for the first time. DRLs can be used as an effective optimization tool for identifying unusually high or low patient doses during X-ray examinations. This study aims to propose institutional DRLs (IDRLs) by measuring the kerma-area product (KAP) of adult patients undergoing routine projection X-ray examinations. The median and the 75th percentile KAP values obtained were compared with that of the single institution KAP values reported from India and Greece. This descriptive cross-sectional study was conducted in a public hospital in Uva province, Sri Lanka, with 400 adult patients aged 18-87 years and weighing 58 ± 20 kg. The patient-specific information (age, sex, weight, and height) and corresponding exposure parameters (tube voltage and current-exposure time product) were obtained. The KAP values were measured, and descriptive statistics were utilized for data analysis. The median KAP values obtained were proposed as IDRLs. The IDRLs in Gy.cm² were 0.23 for cervical spine anterior-posterior (AP), 0.19 for cervical spine lateral (LAT), 0.10 for chest posterior-anterior (PA), 0.06 for knee joint AP, 0.05 for knee joint LAT, 1.47 for KUB AP, 0.85 for lumbar spine AP, 1.97 for lumbar spine LAT, 0.29 for shoulder joint AP, 0.61 for skull PA, and 0.60 for skull LAT examinations. The maximum to minimum ratio of KAP values ranged from 2.4 for KUB AP to 6.3 for the cervical spine AP examinations. The median and the 75th percentile of most of the examinations were comparable to corresponding KAP values reported by the countries mentioned above, except for the skull PA and LAT examinations. Accordingly, interquartile ranges of exposure parameters are recommended for skull examinations to improve the optimization of patient doses.

DIAGNOSTIC REFERENCE LEVELS OF RADIOGRAPHIC AND CT EXAMINATIONS IN SAUDI ARABIA: A SYSTEMATIC REVIEW

A systematic search was conducted to explore the literature on the existing diagnostic reference level (DRL) of radiographic and computed tomography (CT) examinations in Saudi Arabia. The search was performed using Web of Science, Scopus and EBSCO. The search identified 19 studies that reported DRL values for radiographic and CT examinations in Saudi Arabia. Six of those studies reported DRL values for projection radiography, and the remaining studies reported DRL values for CT examinations (n = 13). The entrance surface dose, volume CT dose index (CTDIvol) and dose-length product (DLP) were the most common methods used for establishing the DRLs. Variations were observed in the Saudi DRL values, and this is consistent with the DRL values reported in the literature. Educating and training radiographers to better understand dose minimizing techniques may result in lower patient doses and lower variances in DRL values.

Diagnostic reference level for adult pelvic examination in several hospitals of Taif and Kharaj city, Saudi Arabia

The current study was aimed to estimate the entrance surface air kerma (ESAK, mGy) for adult patients undergoing conventional radiography of Anteroposterior pelvis examination, and finally to establish a local diagnostic reference level (DRL). A total of 500 patients were exposed to diagnostic radiation in four hospitals (coded A, B, C, and D) in Taif and Kharaj city, Saudi Arabia, with different X-ray equipment specifications. Patient demographic data like age (y), body mass index (BMI) in kg/m² as well as exposure factors and X-ray tube output were recorded. ESAK (mGy) was first calculated using the exposure data and tube output values, then the ESAK values were used to estimate entrance surface dose (ESD). The average BMI was 23.9 kg/m². The mean tube potential used in A, B, C, and D hospitals and the corresponding estimated ESD were found to be 74.2, 69.8, 73, 76,7 kVp, and 2.54, 2.64, 2.94, 3.03 mGy respectively. The correlation coefficient between ESAK and BMI was found to be 0.98. When compared to computed radiography (CR), the conventional X-ray digital radiography reduces the radiation exposure in pelvic imaging by a factor of 1.18. The third quartile of median proposed a lower than the DRL of the previous studies.

Local diagnostic reference levels for routine chest X-ray examinations at a public sector hospital in central South Africa

BACKGROUND

Dose optimisation is a radiation protection guideline recommended by the International Commission on Radiological Protection (ICRP) for adherence to the 'as low as reasonably achievable' (ALARA) principle. Diagnostic reference levels (DRLs) are used to optimise patients' radiation protection for diagnostic and interventional procedures and are particularly useful for frequently performed examinations such as chest X-rays.

AIM

To establish the local diagnostic reference levels (LDRLs) for routine chest X-rays.

SETTING

Public sector hospital, Northern Cape province, South Africa.

METHODS

Sixty patients referred for chest X-rays fulfilling the inclusion criteria participated in this study. Patients were ≥ 18 years of age and weighed between 60 kg and 80 kg. Consent for participation was obtained. The entrance skin air kerma (ESAK) was measured by using the indirect method recommended by the International Atomic Energy Agency (IAEA). Statistical software (SAS version 9.2) was used to determine the LDRLs for chest X-rays in three different rooms. In two rooms, computed radiography (CR) was used and the other one was a digital radiography (DR) unit. The LDRL values at the research site were compared with various published international values.

RESULTS

LDRLs for chest X-rays were established. The CR LDRL value for the posteroanterior (PA) chest projection was higher than the DR (flat panel detector [FPD]) LDRL value. The LDRLs of the PA chest projections were 0.3 mGy for CR and 0.2 mGy for DR. The lateral (LAT) chest projection LDRL value was 0.8 mGy for both CR and DR (FPD) projections. The resultant LDRL between rooms at the research site was 0.3 mGy for PA 0.3 mGy and 0.8 mGy for LAT chest projections.

CONCLUSION

The LDRLs for chest X-rays established at this research site were lower than internationally reported DRLs. We recommend that LDRLs for routine chest X-rays should be repeated every 3 years, according to the ICRP.

CONTRIBUTION

Currently, no established or published DRL values prescribed by the Directorate of Radiation Control (DRC) are available in South Africa. The LDRLs established for routine chest X-ray examinations at this research site can serve as a guideline for the establishment of DRL values for other anatomical regions at the research site and other radiology departments in the country.