Your best bet is probably remote desktop software for a single remote user at a time, or teleconferencing software that allows sharing the desktop if multiple users need to view the same session. You can find a description of MS WIndows built-in features for this at Wikipedia:
http://en.wikipedia.org/wiki/Remote_Desktop_Services
It looks like Varian wants that software to run under Red Hat Linux (that's the OS on the Dell computer they recommend), so that may not help. Check with your system administrators, or look on the web. Someone will need admin/root access to install software, adjust firewall settings, and set up logins for remote users.
Searching for "linux desktop sharing", I found the following link that thumbnails a number of products for Windows, MacOS and Unix/Linux:
http://www.kolabora.com/news/2006/10/05/screen_sharing_tools_and_technology.htm
Yes, 2006 is a long time ago in computer years, but it's a place to start looking.
PS: Yes, I know that's not web technology, meaning that the remote user will need a special client and not just any old web browser, but it may be a solution to your needs.