The term “nanotechnology” was coined in 1974 by Japanese scientist Norio Taniguchi (1912–1999) at the University of Tokyo. It includes a number of technologies that deal with the miniaturization of existing technology down to the scale of a nanometer (one-billionth of a meter) in size, about the size of molecules and atoms—1/40,000th the width of a human hair.

The potential of nanotechnology is enormous; for example, it includes microcomputers capable of storing trillions of bytes of information in a space smaller than a dime; portable fluids containing nanobots that are programmed to destroy cancer cells or deliver medicines; the ability to sense and adapt to environmental stimuli such as heat, light, sound, surface texture, and chemicals; and to perform complex calculations faster and more efficiently—singularly or en masse. A push is even in place to develop nanobots that will be able to move, communicate, and work together, assemble things on a molecular level—and to even possibly repair or replicate themselves.

Ultrasound is another type of 3-D computerized imaging. Using brief pulses of ultra-high frequency acoustic waves (lasting 0.01 second), it can produce a sonar map of the imaged object. The technique is similar to the echolocation used by bats, whales, and dolphins.