Dicom is Digital Imaging and Communications in Medicine. It's a medical record that includes pictures.
www dot mccauslandcenter dot sc dot edu/mricro/dicom/ has a list of image handlers for dicom images.
It lists ImageMagick and Irfanview (requires plug-in) as freeware with convertors. I just checked and GIMP lists dicom as a possiblity. These can be used to change from dicom to bmp or png format. From bmp or png you can either paste as an image as Jakub suggests or bring it into Inkscape and have Inkscape create vector paths for export as dxf.