Unfortunately, LG drives do not support disk quality scanning programs at all, as far as I am aware.
You might be able to run a Transfer Rate Test with it, which should give you a smooth curve on a graph as the drive reads the disk. Any sharp downturns in reading speed indicate a problem with the disk, or possibly dirt or smudges on the surface…got to make sure they are clean before running any test.
Open the program with a burned disk already in the drive and hit F2 to start the transfer rate test.
If you want a good drive for scanning, buy a Lite-On, or one of the new Samsung drives like the SH-S203B or SH-S203N. Look in our Samsung forum for the FAQ thread about the necessary registry hack to get Nero CD/DVD Speed to work with Samsung drives if you choose to buy a Samsung for this purpose.