Reporting average glandular dose and its associations with age and exposure parameters

Purpose: To report average glandular dose (AGD) values for the Saudi breast cancer screening program and to examine the relationship between AGD with age and exposure parameters. Methods: Screening mammography of 187,788 exposures were collected. The AGD was calculated per exposure and considering each view (craniocaudal (CC) and mediolateral oblique (MLO)) separately. Spearman correlation, Mann–Whitney U test, and Kruskal-Wallis tests were to test the difference existence in AGD across various age groups and inter- and intra-views (MLO and CC) in acquisition parameters. Results: The mean AGD per projection was 1.45 mGy and most AGD falls between 1.3 and 1.5 mGy for both projections which are close in value to those reported to other countries. The participants have a mean age of 49 years. The mean values for the used exposure parameters were 135 N for compression force (CF), 58 mm for compressed breast thickness (CBT), 29 kVp, and 74 mAs. An inverse relation between AGD and age (r = −0.131, p < 0.001) was found. Additionally, AGD was also correlated with CBT (0.39, p < 0.001), and CF (−0.11, p < 0.001). ADG, CBT, CF, mAs, and kVp, were found to have statistically significant differences between CC and MLO (p = 0.001). The CF was the only parameter that had a significant difference between left and right MLOs (p = 0.016). Conclusion: We observed a trend of decreasing AGD with aging in the women of our population. We also noticed that AGD decreases with higher CFs and lower CBTs. A potential explanation for this is that the composition of the breast is changing (glandular tissue reduces) with aging, allowing more CF and thinner CBT leading to less absorbed AGD.