Radiation dose with digital breast tomosynthesis compared to digital mammography: per-view analysis

Area of Science:

• Radiology
• Medical Imaging
• Radiation Oncology

Background:

• Digital breast tomosynthesis (DBT) is an advancement over digital mammography (FFDM).
• Concerns exist regarding the potential increase in radiation dose with DBT.
• Previous studies often compared DBT combined with FFDM versus FFDM alone.

Purpose of the Study:

• To directly compare the radiation dose delivered by FFDM and DBT for a single imaging view.
• To assess the mean glandular dose (MGD) for both FFDM and DBT examinations.
• To evaluate the impact of DBT on radiation exposure in breast cancer screening.

Main Methods:

• Utilized 4,780 FFDM and 4,798 DBT images from 1,208 women in a screening trial.
• Employed automatic software to determine volumetric breast density (VBD) from raw images.
• Calculated mean glandular dose (MGD) using Dance's model based on VBD and exposure data.

Main Results:

• Statistically significant differences in MGD were observed between FFDM and DBT for both CC and MLO views (p<0.0001).
• DBT resulted in a higher MGD compared to FFDM (CC: 1.858 mGy vs. 1.366 mGy; MLO: 1.877 mGy vs. 1.374 mGy).
• Bland-Altman analysis indicated an average 38% increase in DBT dose over FFDM, ranging from 0% to 75%.

Conclusions:

• Tomosynthesis shows a modest increase in breast radiation dose compared to FFDM.
• The radiation burden from DBT should not deter its use, especially with synthetic 2D imaging.
• Clinical benefits of DBT should be prioritized over minor radiation dose concerns.