Shift method Mean [mm] Median [mm] (Standard Deviation) (Range) A/P L/R S/I Radial A/P L/R S/I Radial CT shifts -1.5 -1.6 -0.6 8.3 -3 -1.3 0 7.3 (all patients) -6.3 -5.3 -3.6 -6.3 (-11.2:10.7) (-13.7:7.1) (-10.2:4.7) (2.4:14.5) US shifts -1.8 -2.5 -0.6 9.7 -1.3 -0.9 -0.6 10.1 (all patients) -6.1 -6.7 -4.3 -4.1 (-11.4:11.9) (-17.9:9.8) (-8.6:7.8) (2.5:16.7) Clip shifts -0.6 -2.2 0.1 3.4 0.1 -1.8 0.2 3.2 (clip patients) -3 -4.6 -3.7 -3.7 (-5.5:3.5) (-9.4:7.5) (-5.6:5.8) (0.0:9.8)

Table 1: Mean, standard deviation, median and range of the lumpectomy cavity displacements according to CT, 3DUS and clips, in the anterior/posterior (A/P), left/right (L/R), superior/inferior (S/I) and radial directions.(Results for clips are reported only for the subset of patients with clips).