128 H. Khajmi et al.: Radioprotection 2026, 61( 2), 126 – 131
IF is the irradiation field in cm 2, and BSF is the backscattered factor. As per the study of Leclet in 2016( Leclet, 2016), BSF is equivalent to 1.35 for voltages ranging from 60 to 80 kV and 1.5 for voltages over 80 kV.
2.3 Statistical assessment
The data was organized for analysis using Microsoft Excel 2019. Typical DRL values were computed as median distributions for each radiographic examination, in line with the International Commission on Radiological Protection Publication 135( ICRP, 2017). Descriptive statistics, including the mean, median, 50th percentile, and 75th percentile values of the dosimetric variable of ESD, were utilized to evaluate the information. Additionally, the minimum, maximum, and average values of voltage( kV) and intensity( mAs) were calculated. We conducted a thorough analysis by comparing the TDRLs values with DRLs from significant studies carried out around the world: in France in 2013( Roch et al., 2013), throughout the European Union in 2014( EC, 2014), in the United Kingdom in 2016( UK, 2016), in Nigeria in 2017( Joseph et al., 2017), in Iran in 2020( Hoseini et al., 2020), and in Ghana in 2023( Gyan et al., 2023). This comprehensive comparison highlights the relevance of our findings within the context of international standards and practices.
3 Results and discussion
In this study, we examined all the radiographs performed in the radiology department of the Arrazi hospital over a fivemonth period during the year 2022, in order to determine the TDRL values, in line with the description of the different DRL categories in ICRP135( ICRP, 2017).
The total number of adult patients included in this research is 1170. 62 %( n = 756) were men, and 38 %( n = 414) were women. Figure 1 shows that the most common radiographs are chest, knee and abdominal radiographs with a percentage of 30 %, 19 % and 10 % respectively. Radiographs of the pelvis, lumbar spine, cervical spine and skull did not exceed 7 %. For each of the eight radiographs, the average tube potential( kVp), tube current( mAs) and exposure time( ms) were obtained and are presented in Table 1. The minimum and maximum age criteria for all examinations were 19 and 84 yr, respectively. For the kV, the range is 44 kV to 125 kV; for the mAs, the range is 1 mA to 113 mAs; andfor exposure time inmilliseconds, therange is1 ms to 208 ms. The large ranges of kV, mAs and ms were caused by the significant variations in patient size, weight, height and radiographic techniques used by radiology technicians. The documented technical radiographic parameters show that there are variations in technical factors when compared to the recommendations of the European Commission Quality Criteria( EC, 1996). Table 3 summarizes the calculated mean and the 50th and 75th percentiles of the entrance surface dose in mGy for each projection and examination considered.
For all examinations and projections, the estimated mean ESD ranged from a minimum of 0.24 mGy to a maximum of 4.59 mGy. Whereas the established typical DRL values for the entrance surface doses of all radiography projections were 1.52 mGy, 1.46 mGy, 3.34 mGy, 4.76 mGy, 1.56 mGy, 1.98 mGy, 1.25 mGy, 0.58 mGy, 0.58 mGy, 2.2 mGy, 2.1 mGy,
Fig. 1. Frequency distribution of radiographs studied.
and 0.22 mGy, for cervical spine AP, cervical spine LAT, lumbar spine AP, lumbar spine LAT, abdominal X-ray AP, pelvis X-ray AP, shoulder AP, knee AP, knee LAT, skull AP, skull LAT, and chest PA, respectively.
The typical DRL of ESD of 4.76 mGy for lumbar spine LAT radiography is higher than the other values. This is due to higher exposure parameters( i. e., kVp and mAs) than for the other examinations. The field size is another factor influencing the diagnostic reference level, which is larger for the abdomen than for the other radiographs. The chest X-ray AP projection had the lowest TDRL of ESD at 0.22 mGy, indicating lower exposure compared to the other radiographs.
In this study, the TDRL of the cervical spine AP and LAT( 1.52 mGy / 1.46 mGy), the knee AP and LAT( 0.58 mGy / 0.58 mGy), and the skull AP and LAT( 2.2 mGy / 2.1 mGy) are approximately identical; the discrepancy does not exceed 4 %. This indicates that the radiology technicians at Arrazi hospital do not change the acquisition parameters between AP and LAT projections for these examinations. However, because the patient width is greater in the LAT position than in the AP position, the TDRL of 4.76 mGy of the LAT lumbar spine is 142 % higher than in the AP lumbar spine of( 3.34 mGy). In comparison of the median value of ESD for the abdominal X-ray( 1.56 mGy) AP projection and the pelvic X-ray( 1.98 mGy) AP projection, the TDRL value of the pelvic X-ray AP projection is 26 % higher. For the shoulder X-ray AP projection, Table 2 shows that the TDRL( 1.25 mGy) is 82 % higher than that for the chest X-ray AP projection( 0.22 mGy). The use of a high mAs( 1 – 85 mAs) and kilovolt( 50 – 77 kV) in this radiography could be behind the high dose delivered to the patients.
The high dose values observed in certain examinations in our survey may be due to inadequate training of imaging staff or to variations in technical parameters, clinical complexity of patients, and untimely quality control programs. The above finding is not unique to this study, this is confirmed by a study in Ghana( Ofori, 2013) and Nigeria( Joseph et al., 2017), but is common in other developing countries( Johnson et al., 2000; Wall et al., 2001; Kings et al., 2002).
The quantity of DRLs is contingent on numerous factors that influence patient exposure. The kVp has an effect on both the quantity and quality of the radiation beam, and for all radiography devices, the output increases with increasing kVp,