Yes, OfficeScan generates a log file in date format in the C:\program file\trend micro\officescan client\report directory.

This would be something similar to C:\program file\trend micro\officescan client\report\20080925.log and will record the start time:

Start time : Thu Sep 25 2008 13:00:08

This log file also records that the Damage Cleanup Engine (DCE) has run, as a scheduled or manual scan will run the DCE during startup.

Third party monitoring and auditing software can query this file or look for it as the file is only created once a scan starts.