http://www.santafenewmexican.com/news/health_and_science/using-sound-to-see-through-solid-objects/article_a1c03aa7-d9eb-5db6-88ec-fba838b2d859.html

To foil supervillains, Superman relies on his X-ray vision to see through shielded objects to expose dangerous items, such as explosives laced with kryptonite. At Los Alamos National Laboratory, a team of scientists in the Materials Synthesis and Integrated Devices group have invented a technology that works somewhat like Superman’s X-ray vision.

Instead of eye beams, this new technology, known as ACCObeam (Acoustic Collimated Beam), uses a new type of sound beam to pierce through physical barriers such as cement, rock and metal and produce high-resolution images of what lies beyond, be it an explosive hidden in a suitcase or an unstable oil well deep in the earth that could fracture and collapse at any given moment.