This is an international format that was developed for the purpose of storing images of the body taken with medical imaging equipment. It includes magnetic resonance and computer tomography images, ultrasound images and fluoroscopy, as well as images taken with other medical imaging equipment. DCM also stores patient information in the metadata, which form part of a single file.
BMP is format for storing bitmap images. In this format, you can only save bitmaps monolayer. For each pixel in different files may come different number of bits. The latest versions of the BMP has the ability to control color. In particular, you can specify the endpoints perform gamma correction and embed color profiles ICC.