A method and system are presented for generating a DRR of an anatomical region so that the visibility within the DRR of one or more skeletal reference structures is enhanced. 3D scan data, which have been obtained from a 3D scan of the object conducted at a 3D scan energy level, are provided. The 3D scan data are modified to compensated for a difference between the ratio of bone-to-tissue attenuation at the 3D scan energy level, and the ratio of bone-to-tissue attenuation at the intensity of the imaging beam which the DRR emulates. The modified 3D scan data are related to the raw 3D scan data by a non-linear, exponential relationship. A plurality of hypothetical rays are cast through the modified 3D scan data, from the known geometry of the imaging beam. The 3D scan data are integrated along each hypothetical ray, and the integrated values are projected onto an imaging plane.