Low dose photon-counting digital breast tomosynthesis: comparison with a commercially available tomosynthesis unit in the detection and characterization of breast carcinomas.

Purpose: Digital Breast Tomosynthesis (DBT) has a diagnostic accuracy higher than 2D-FFDM, with a slightly higher Average Glandular Dose (AGD). Photon-counting technology was demonstrated to reduce AGD of 2D-FFDM, while preserving a high image quality; it therefore represents an interesting solution to significantly reduce the radiation dose of DBT. Our purpose is to compare the image quality and the AGD of a photon-counting DBT prototype with a conventional DBT unit in the detection of breast carcinoma.

Materials and methods: In this preliminary prospective study, 17 women with a suspicious breast finding (BI-RADS 4c/5) were enrolled. Before biopsy, they underwent bilateral 2-view DBT with a conventional unit and a photon-counting prototype. The AGD delivered by the two DBT units were compared. Three readers independently reviewed and compared the images (DBT and synthesized 2D) giving a density, BI-RADS and conspicuity score focusing on suspicious findings. All women underwent core-needle biopsy with imaging guidance and histology was used as standard reference.

Results: In 15 examinations at least one suspicious finding was detectable by both systems. Two exams were falsely negative with both units due to high density and small cancer size. All suspicious findings were histologically confirmed as malignant. There was no significant difference in density and BI-RADS scores. The conspicuity of findings was scored as equal or better for photon-counting DBT in 94% observations. The mean AGD delivered by photon-counting DBT was 55% lower than the conventional DBT.

Conclusion: According to these preliminary data, photon-counting DBT provides a high image quality, like a conventional DBT unit, with a drastic reduction of the AGD delivered.

Trial registration number: The clinical trial "Low Dose Tomosynthesis Compared to Traditional Tomosynthesis" has an identifier number NCT02771444 on the ClinicalTrials.gov website. It was first registered on 11.05.2016.