Introduction of a figure of merit to jointly assess image quality and dosimetry in digital mammography

Abstract

Purpose: the aim of this study was to jointly analyze image quality and mean glandular dose in digital mammography.

Methods: 8 systems were evaluated during 2016 and 2017: Giotto I3DL (3 units), Fujifilm Amulet FDR (3 units) and Hologic Selenia (2 units). The image quality was quantified by analyzing the contrast thickness threshold, and dose results were obtained by measuring the mean glandular dose at clinical conditions for different thicknesses of polymethyl methacrylate. A figure of merit is introduced, Q, in order to evaluate image quality and dosimetry altogether.

Results: the Selenia units presented better image quality at the cost of a higher mean glandular dose for all polymethyl methacrylate thicknesses. The Giotto units presented a lower glandular dose for all polymethyl methacrylate thicknesses. The figure of merit showed approximately the same assessment for all mammographs, except for two Giotto I3DL systems, which obtained a better assessment.

Conclusion: a figure of merit has been introduced, not based on the contrast-noise relation, which assesses image quality and dosimetry altogether, and whose tolerances are independent of the spectrum used.