Compression thickness dependence of surface dose (Kair = air kerma) at the position of the thyroid gland (phantom measurements) for one CC view. Blue dots represent measures obtained with a PMMA phantom mimicking the compressed breast tissue and the patient’s body represented by an Alderson phantom; the measurements were taken with a RQM sensor directed horizontally to the beam, perpendicular to the beam axis (see Fig. 1). Red squares indicate measurements with the same PMMA slab phantom, but without Alderson phantom. The measurements were performed with a SEQ-6R dosimeter. Green triangle represents a measurement with SEQ-6R dosimeter using a Pb-shield directed upward to omit scatter and leakage radiation coming from the collimator system. Error bars represent standard deviations. The blue solid line is an exponential fit to the blue dots: Kair = 3.837μGy ⋅ exp(0.3433cm−1 ⋅ Compression).