On the face of it, though, relying on a single source limits the sorts of wave that can be produced, and therefore the types of task they can perform.

ECONOMIST: Acoustic microfluidics

In the U.S., the TSA uses both types of scanners: 250 X-ray scanners and 264 millimeter wave scanners.

FORBES: Europe Bans Airport Body Scanners For "Health and Safety" Concerns