Dosimetric assessment of fetal radiation dose in clinical mammography.

Abstract

Objective . We quantify fetal radiation exposure from standard clinical mammography protocols and assess whether routine pregnancy verification is necessary before clinically indicated mammography. Approach . Measurements were performed on a Hologic Selenia Dimensions system using an Alderson Rando Female anthropomorphic phantom with tissue-equivalent breast slabs. Standard craniocaudal (CC) 2D mammography and tomosynthesis were acquired for two compressed breast thicknesses and four sets of imaging parameters. Air kerma was measured with a calibrated RaySafe Xi Survey detector at representative locations corresponding to the first, second and third trimesters; each configuration was repeated three times and a single configuration was repeated after fully rebuilding the setup to estimate positioning-related variability. Main results Mean measured fetal doses were 0.048μGy-0.264μGy (first trimester), 0.017μGy-0.084μGy (second trimester) and 0.753μGy-7.253μGy (third trimester). Across protocols, CC projections yielded 0.017μGy-2.462μGy and tomosynthesis 0.037μGy-7.253μGy. Dose increased with breast thickness and was highest in the third trimester, consistent with increased scatter and shorter path to the fetus. Between-setup variability for the rebuilt configuration was 36.2%. Significance . Fetal dose from mammography was several orders of magnitude below thresholds associated with deterministic fetal effects and the highest measured values remain far below levels that can be considered clinically significant. These findings suggest that clinically indicated mammography should not generally be delayed solely on the basis of pregnancy status, while recognising that decisions must follow local guidelines, institutional or national policies and individual risk considerations. Routine pregnancy screening prior to mammography is unlikely to provide meaningful clinical benefit in the context of radiation safety.