Presenter Dr. Francesca Proulx, of Harvard Medical School and Beth Israel Deaconess Medical Center, and colleagues investigated the effects of breast tissue thickness, density, and patient age on mean glandular radiation dose received at digital breast tomosynthesis.
The study included 200 screening DBT exams, and the mean age of the patients was 56. The DBT protocol included 2D and 3D acquisitions; Proulx's team recorded patient age, density, compression thickness, and total mean glandular dose for the two standard views (craniocaudal and mediolateral oblique) per breast.
In all, 110 of the exams showed low-density tissue, while 90 showed high density. The overall average total mean glandular dose was 14.95 mGy and the overall average tissue thickness was 57.3 mm, the researchers found.
In low-density tissue, the average total mean glandular dose was 15.3 mGy and the average thickness was 61.2 mm. For high-density tissue, the average total mean glandular dose was 14.23 mGy and the average thickness was 52.6 mm.
Tissue thickness had a stronger correlation with radiation dose for patients with less-dense breasts than for those with denser tissue, which suggests that total mean glandular dose increases more quickly with an increase in thickness for patients with low-density breasts than for patients with high-density breasts, according to the group.
"For patients undergoing screening DBT, breast thickness should be considered as an important contributor to overall radiation dose in addition to breast density and patient age," Proulx and colleagues concluded.