They used a portable X-ray device to give the cables the superman treatment.

CNN: Challenger explosion

The LEXID (Lobster Eye X-ray Imaging Device) functions by "radiating objects with tiny amounts of X-ray energy, " subsequently allowing its user to see behind steel, wood or concrete.

ENGADGET: LEXID prototype gun can peek through walls

X-ray detectors for identifying impurities in semiconductor chips (among other things) would be interested in such a device.

ECONOMIST: Microrefrigeration