Abstract
OBJECTIVE: Breast compression is used in mammography to improve image quality and reduce radiation dose. However, optimal values for compression force are not known, and studies have found large variation in use of compression forces between breast centres and radiographers. We investigated breast compression parameters, including compression force, compression pressure and compressed breast thickness across four consecutive full field digital mammography screening examinations for 25,143 subsequently screened females aged 50-69 years. METHODS: Information from females attending four consecutive screening examinations at two breast centres in BreastScreen Norway during January 2007 - March 2016 was available. We compared the changes in compression force, compression pressure and compressed breast thickness from the first to fourth consecutive screening examination, stratified by craniocaudal (CC) and mediolateral oblique (MLO) view. RESULTS: Compression force, compression pressure and compressed breast thickness increased relatively by 18.3, 14.4 and 8.4% respectively, from first to fourth consecutive screening examination in CC view (p<0.001 for all). For MLO view, the values increased relatively by 12.3% for compression force, 9.9% for compression pressure and 6.9% for compressed breast thickness from first to fourth consecutive screening examination (p<0.001 for all). CONCLUSION: We observed increasing values of breast compression parameters across consecutive screening examinations. Further research should investigate the effect of this variation on image quality and females' experiences of discomfort and pain. ADVANCES IN KNOWLEDGE: Breast compression force, compression pressure and compressed breast thickness increased across consecutive screening examinations, which might be of influence for the females' experiences of discomfort and pain during the examination and for image quality.