Establishment of diagnostic reference level for digital mammography in northern Saudi Arabia

This retrospective multicenter study aimed to establish local diagnostic reference levels (LDRLs) for digital mammography and assess radiation dose variability across five government hospitals in northern Saudi Arabia. A total of 1729 mammographic examinations performed between January and June 2024 were analyzed. Data included patient demographics, technical parameters (kVp, mAs, compression force, and compressed breast thickness), and dose metrics, average glandular dose (AGD) and entrance surface exposure (ESE), for standard craniocaudal (CC) and mediolateral oblique (MLO) views. Following the methodology outlined in ICRP Publication 135 (2017), LDRLs were derived as the 75th percentile of the median dose values from the participating facilities for examinations performed at a compressed breast thickness of 50 ± 5 mm. Statistical analysis employed the Kruskal-Wallis test for inter-center comparisons and Spearman correlations to examine relationships between dose and technical parameters across the dataset. Significant inter-center variability was observed (p < 0.001), indicating notable differences in clinical technique and dose optimization practices. The combined 75th-percentile AGD was 1.27 mGy, with MLO projections requiring higher doses than CC views (AGD = 2.47 mGy vs. 1.22 mGy). AGD demonstrated strong positive correlations with mAs (r = 0.781) and compressed breast thickness (r = 0.609), while compression force showed a weak negative correlation (r = -0.185), confirming the impact of both patient-related and technical factors on radiation dose outcomes. The established LDRL falls within previously reported Saudi values and remains lower than many international benchmarks, indicating that mammography practices in northern Saudi Arabia are well optimized and aligned with global standards, while highlighting the need for continued protocol standardization across centers.