The DCM file extension is used for image file saved in the Digital Imaging and Communications in Medicine (DICOM) image format. This format was created by the National Electrical Manufacturers Association (NEMA) to view medical images.
The DCM file extension is used for music file or "module" encoded in the DCM format. It is a older audio format.
The DCM file extension is associate with DiskCatalogMaker, a file cataloging and organization program only for the Mac. DCM file contains database files.