if you are on verion 12.1 there will be NO RTVSCAN.exe its been replaced
ccsvchost takes care of everything now
check if this process is running to confirm that scan is running
https://www-secure.symantec.com/connect/forums/sep-121-scan-bar#comment-5937741
and also if you want to check what files are scanned you can enable this log
How to log all files and directories scanned during On-Demand / Scheduled Scan with Symantec Endpoint Protection 11.0
http://www.symantec.com/business/support/index?page=content&id=TECH103126