134 N. A. Alomairy et al.: Radioprotection 2026, 61( 2), 132 – 139 Table 1. Descriptive statistics of patient dose and technical parameters during mammography. Projections Tube voltage( kVp) Tube current( mAs) CBT( mm)
|
All
Cranio-caudal( CC)
Mediolateral Oblique( MLO)
|
Mean SD Range Mean SD Range Mean SD Range |
29.14 1.47 26 – 39 28.55 1.14 26 – 39 29.72 1.53 27 – 39 |
63.03 18.40 30 – 177 56.16 12.94 30 – 123 69.90 20.37 37 – 177 |
46.20 15.91 10 – 100 39.70 10.63 15 – 72 52.70 17.57 10 – 100 |
SD, Std. deviation. |
|
|
|
|
Table 2. Mean, median, range, 1st quartiles, 3rd quartiles values of the ESD and MGD for all examinations.
Variables |
ESD( mGy) |
MGD( mGy) |
|
Mean ± SD |
Median |
1 st quartiles |
3 rd quartiles |
Mean ± SD |
Median |
1 st quartiles |
3 rd quartiles |
All |
1.06 ± 0.35 |
1.00 |
0.87 |
1.22 |
0.35 ± 0.11 |
0.34 |
0.30 |
0.42 |
Cranio-caudal( CC) |
0.96 ± 0.36 |
0.94 |
0.80 |
1.13 |
0.32 ± 0.11 |
0.34 |
0.28 |
0.41 |
Mediolateral-Oblique( MLO) |
1.18 ± 0.45 |
1.07 |
0.94 |
1.30 |
0.36 ± 0.11 |
0.34 |
0.30 |
0.42 |
SD: Std. deviation
tube voltage( kVp), tube current-time product( mAs), and entrance skin dose( ESD in mGy). Linearity, normality, and homoscedasticity assumptions were checked before using the model. Statistical significance was set at a P-value threshold of less than 0.05.
3 Results
3.1 Assessment of mean glandular dose( MGD) in mammography
The study sample consisted of 325 patients in total who underwent X-ray mammography at the university hospital. The descriptive statistics for patient dose and technical parameters during mammography, including tube voltage( kVp), tube current( mAs), and compressed breast thickness( CBT), are presented in Table 1. Across all projections, the mean tube voltage was 29.14 kVp( SD = 1.47, range: 26 – 39 kVp), the mean tube current was 63.03 mAs( SD = 18.40, range: 30 – 177 mAs), and the mean compressed breast thickness was 46.20 mm( SD = 15.91, range: 10 – 100 mm). For the craniocaudal( CC) projection, the mean tube voltage was 28.55 kVp( SD = 1.14, range: 26 – 39). The mean tube current was 56.16 mAs( SD = 12.94, range: 30 – 123 mAs), and the mean compressed breast thickness was 39.70 mm( SD = 10.63, range: 15 – 72 mm). In the mediolateral oblique( MLO) projection, the mean tube voltage was 29.72 kVp( SD = 1.53, range: 27 – 39 kVp), with a higher mean tube current of 69.90 mAs( SD = 20.37, range: 37 – 177 mAs), and a mean compressed breast thickness of 52.70 mm( SD = 17.57, range: 10 – 100 mm).
Table 2 shows the descriptive statistical distribution of ESD and MGD values in both types of examination. For ESD, the average value was 1.06 mGy, while the median was 1 mGy. The distribution of ESD around the average and median is quite regular; the first and third quartiles range from 0.87 to 1.22 mGy. For the CC examination, the average exposure was 0.96 mGy, while the MLO examination is higher with an average of 1.18 mGy. The mean and median are very close for the CC examination, so the distribution is rather symmetrical. The range from the first quartile of 0.80 mGy to the third quartile of 1.13 mGy is moderately variable. The mean and median for the MLO examination are slightly higher compared to the CC examination, indicating that the doses in this examination tend to be somewhat higher overall. The quartile range is also a little broader than in the CC examination, with a range of 0.94 to 1.30 mGy. In the case of MGD, the mean of all is 0.35 mGy with a median of 0.34 mGy, and the interval between the 1st and 3rd quartiles is from 0.30 to 0.42 mGy. The MGD distributions for the CC and MLO examinations are comparable, with the CC having a mean of 0.32 mGy and the MLO slightly higher at 0.36 mGy. Overall, the data shows modest variability in ESD and MGD, with slightly higher ESD values observed during the MLO examination.
3.2 Analysis of the factors influencing MGD
The correlation analysis between several key mammographic variables, including age, tube voltage( kVp), tube current-time( mAs), compressed breast thickness( CBT), entrance skin dose( ESD), and mean glandular dose( MGD) are shown in Table 3. The results indicate that age is weakly