To convert Alcohol 120% MDF image file into the more standard ISO image format, you'll need to install mdf2iso.
~$ sudo apt-get install mdf2iso
It's a small piece of software that shouldn't take long to download and install.
~$ mdf2iso filename.mdf
Replace filename with the filename of the MDF image file. It's that simple. You should soon have a ISO image file by the same name in the same location as the MDF file.
Splitting Cue/Flac files
Converting Cue/Bin to ISO
Dealing with UIF files