Early experiences with the technical assessment of digital breast tomosynthesis systems

Digital breast tomosynthesis (DBT) is a new breast imaging technique which relies upon acquisition of multiple projection views over a limited angular range to reconstruct a volumetric image. DBT systems have been available for clinical use since 2009 and in 2011 the Hologic Dimensions was the first DBT system to receive FDA approval in the United States. Commercially available DBT systems have been the subject of a number of technical evaluations and the results have been published in the literature. However, given the novelty of the technique, technical performance standards for quality assurance (QA) of DBT systems have not yet been fully established. The National Cancer Screening Programme acquired five new Hologic Dimensions of DBT systems at the end of 2014. These systems were commissioned using the draft QA protocol for DBT systems published by the European Reference Organisation for Quality Assured Breast Screening and Diagnostic Services (EUREF) in 2014. Although still only available in draft form, this protocol offers guidance on QA measurements for DBT systems, and should help to ensure performance stability. Results from the commissioning showed that conventional and tomosynthesis technical performance was well matched between the five new systems. Dose and image quality measurements were found to be comparable with those obtained in other similar studies. It is clear the EUREF QA protocol still requires further development. However much experience was gained during this commissioning project which it is hoped will contribute to the development of the technical assessment of DBT systems.