ntrtscan.exe is a part of the Trend Micro AntiVirus application. This process should not be removed to ensure that your system is secure.
The ntrtscan.exe process is a core part of OfficeScan nt. If you stop this process your anti virus software may not be effective in preventing infection of your computer by viruses, so if possible you should leave it running.
ntrtscan.exe is an application that does NOT appear to be a security risk