1. A Computer-Aided Diagnosis (CAD) apparatus comprising: an input device which receives a first image of a user captured by emitting X-rays towards the user, and receives a second image of the user that is discriminated from the first image; an information acquisition device which acquires a bone model of the user based on the second image; and a CAD device for compensating for the first image based on the bone model, wherein the information acquisition device acquires information of at least one of a position of a bone of the user and a shape of the bone of the user, and generates the bone model based on the position of the bone or the shape of the bone, wherein the information acquisition device acquires a bone structure of the user from the second image, sets at least one point in the bone structure, and generates the bone model including position information of the set at least one point, and wherein the second image includes a tomosynthesis image of the user.