In December 2012, Oslo University Hospital completed The Oslo Tomosynthesis Screening Trial (OTST), a large-scale prospective 2-year study evaluating DBT in a high volume screening setting. It was conducted within the Norwegian Breast Cancer Screening Program (NBCSP). The trial focused mainly on cancer detection, comparing the combination of DBT plus FFDM with conventional full field digital imaging (FFDM) [1]. DBT (together with FFDM) was offered to all women attending the screening centre in Oslo County. Participation was voluntary.

The NBCSP is a population based breast cancer screening programme organised by the Cancer Registry of Norway and assures that all women between the ages of 50 and 69, every second year, receive an invitation to attend their local screening centre. Each centre follows the National Quality Assurance Manual (QAM); this document contains guidelines for various professions, including radiographers and others working within the screening programme.

Mammography screening in Oslo County is a continuous workflow performed by a team of three radiographers per screening lab. Each lab in the centre is designed with an adjacent interview room and two changing rooms. One radiographer interviews the women, the second is able to position women for imaging, and the third makes the exposures and assesses the quality of the images. Images are evaluated immediately on a 3-mega-pixel monitor before the woman leaves the screening centre. All images are sent to the picture archiving and communication system (PACS), prior to the woman leaving. This quality process reduces the number of women that need to return for follow-up due to poor images or for technical reasons when the images are interpreted independently by two radiologists at later date. For FFDM, approximately 5 min per mammography examination is allocated, a maximum of 12 women per hour; for DBT combined with FFDM, 10 women per hour.