Evaluation of average glandular dose (AGD) in screening and diagnostic digital mammography and digital breast tomosynthesis (DBT) towards establishing a reference dose range band (DRB): a developing country experience

Abstract

This study represents the first national survey conducted in Sri Lanka to establish national diagnostic reference levels (NDRLs) for screening and diagnostic acquisitions in digital mammography (2D-DM) and digital breast tomosynthesis (DBT). Additionally, the study investigated the relationship between average glandular dose (AGD) and compressed breast thickness (CBT) and introduced a novel concept called dose range bands (DRBs) as a tool for optimizing radiation dose in mammography. DICOM metadata was used to extract dose data and exposure parameters from women undergoing either screening (350) or diagnostic (750) DM. The analysis included both craniocaudal and mediolateral oblique views of each breast, acquired using 2D-DM and DBT imaging techniques. The NDRL (AGD per view) was 1.97 mGy and 2.01 mGy for diagnostic DM and DBT, respectively. The corresponding NDRLs for screening acquisition were 2.44 mGy and 2.30 mGy. The mean DBT/DM AGD ratio was 1.39 and 0.97 for diagnostic and screening, respectively. Further, the association between the average glandular AGD per view and CBT is stronger in DBT than in 2D-DM. The study findings highlight the need for standardisation of compression practices, considering factors such as the radiographer’s experience, imaging equipment, breast density, age, breast size, and pain threshold.