1. An X-ray machine having a non-transitory computer-readable medium encoded with program instructions which, when executed by a processor of the x-ray machine, comprises: producing a three-dimensional image of a breast; identifying lactiferous ducts and associated glandular bodies in the image; determining a position of an object relative to at least one of the lactiferous ducts and glandular bodies; recording the relative position in the computer-readable medium; and thereafter re-determining the position of the object from the previously recorded relative position even through orientation or configuration of the breast has changed.