The 3D mammographydifference between traditional mammography (2D) and 3D mammography is that with the 3D mammography the breast is being imaged in 1mm slices.  This reduces or eliminates breast tissue overlapping and allows a more accurate evaluation, resulting in fewer recalls and fewer biopsies.  The procedure still requires the breast to be compressed in the standard manner and the radiation dose is still well below the standards set by the governing bodies.  The 3D mammogram increases the sensitivity of breast cancer detection and allows small lesions to be seen that may otherwise be hidden with the traditional 2D mammogram.