DRR generation and enhancement using a dedicated graphics device are described herein. In one embodiment, an example of a process for generating DRR (digitally reconstructed radiography) images includes, but is not limited to, loading a volume rendering program into a graphics device, the volume rendering program representing a predetermined algorithm according to a non-linear attenuation model. In response to 3D scan data, the graphics device is invoked to execute the volume rendering program to perform at least a portion of volume rendering operations on at least a portion of the 3D scan data, which may include modifying the 3D scan data according to the predetermined algorithm to compensate for a difference between a first attenuation of an object with respect to a second attenuation associating a known intensity of the object. Other methods and apparatuses are also described.