Comparative Benefit-to-Radiation Risk Ratio of Molecular Breast Imaging, Two-Dimensional Full-Field Digital Mammography with and without Tomosynthesis, and Synthetic Mammography with Tomosynthesis

Abstract

Purpose: To apply previously published benefit-to-risk ratio methods for mammography and molecular breast imaging (MBI) risk estimates to an expanded range of mammographic screening techniques, compressed breast thicknesses, and screening views.

Materials and methods: Only previously published estimates were used; therefore, this study was exempt from the requirement to obtain institutional review board approval. Benefit-to-risk ratios were calculated as the ratio of breast cancer deaths averted and lives lost to screening over 10-year intervals starting at age 40 years for MBI, two-dimensional (2D) full-field digital mammography (FFDM) alone, 2D FFDM with synthetic mammography, and 2D FFDM with tomosynthesis for two-, four-, and five-view screening mammography and compressed breast thicknesses of 20-29 mm, 50-59 mm, and 80-89 mm.

Results: Central estimates of the benefit-to-risk ratios ranged from 3 to 179 for screening mammography and from 5 to 9 for MBI. Benefit-to-risk ratios for MBI were inferior to those for mammography for most scenarios, but MBI may be performed at an equal or superior benefit-to-risk ratio for women aged 40-59 years with a compressed breast thickness of at least 80 mm and for those undergoing mammographic screening examinations with four or five views per breast. The benefit-to-risk ratios across all ages with use of tomosynthesis plus 2D FFDM as a screening examination were 45% lower than those for tomosynthesis plus synthetic mammography.

Conclusion: Benefit-to-risk ratios for MBI are within the lower range of those for mammography when accounting for variation in mammography technique, compressed breast thickness, and age. Benefit-to-risk ratios of synthetic mammography plus tomosynthesis are superior to those of tomosynthesis plus 2D FFDM.Keywords: Breast, Mammography, Molecular Imaging, Molecular Imaging-Cancer, Radiation Safety, Radionuclide Studies, Screening, Tomosynthesis© RSNA, 2019See also the commentary by Hruska in this issue.

Figure:

Chart shows estimated net deaths averted per 100 000 women screened. Data were calculated by subtracting the estimated lives lost from screening from the estimated deaths averted with screening. FFDM = full-field digital mammography, MBI = molecular breast imaging, synthetic = synthetic mammography, tomo = tomosynthesis, 2D = two-dimensional.