Breast Glandularity Distribution and Refining the Mean Glandular Dose Estimates in Digital Mammography

In mammography, radiation dose is typically expressed as the mean glandular dose (MGD), which represents the dose delivered to the glandular tissue of the breast.

This study compares MGD estimates obtained using three different methodologies: (I) MGD-Dance-Laboratory for Individualized Breast Radiodensity Assessment (LIBRA) - Calculated manually for each patient using Dance's formula, incorporating mammographic breast density values derived from the LIBRA application, thereby replacing Dance's standard glandularity assumption with image-specific values; (II) MGD-Dance - Calculated using Dance's formula with the conventional assumption of 50% glandularity; (III) MGD-Displayed - Extracted directly from the Digital Imaging and Communication in Medicine header of each mammogram.

A total of 688 anonymized mammograms from 172 women undergoing routine screening were analyzed, with complete technical and patient-related data. The mean MGD values obtained by the three methods were: MGD-Dance-LIBRA: 2.97 mGy; MGD-Dance: 2.78 mGy; and MGD-Displayed: 2.81 mGy. The average glandularity across the dataset was estimated at 14%. A strong correlation was observed between MGD-Dance and MGD-Dance-LIBRA values (R² =0.9865). The refined dose estimation using image-specific glandularity from LIBRA consistently produced slightly higher values compared to the standard Dance method, highlighting the impact of the commonly assumed 50% glandularity, which overestimates the true average density.

Incorporating individualized breast density estimates from the LIBRA application into Dance's formula provides a more refined and accurate method for calculating MGD in digital mammography.