The biofilters from Star Trek may some day become reality. The Star Trek biofilter is a device that scans for harmful biological substances and it was primarily used as part of the transporter system. This technology that seemed so fantastical might soon be seen in airports, hospitals, postal offices, and ports. The technology is called a terahertz scanner. Terahertz ray technology is being researched as a way to identify bioterrorism agents in amounts as small as parts per billion. Terahertz scanners operate on a different area of the spectrum from x-rays so scans from them would not be harmful to people. These scanners, if perfected, could be installed to check packages for harmful agents or to check people entering and leaving secure areas to determine if they are carrying a harmful agent. The scanners work in real time so there is no need to wait for an interpretation of a scan. People could walk through an area normally and only be stopped if there was a concern with the terahertz findings.
See this article in the New Jersey times for more details.