Terahertz waves: radiology without radiation hazards.

Terahertz waves: radiology without radiation hazards. Novel possibilities of radiology arising from the application of a time-resolving terahertz (THz) spectrometer are discussed. Spectrally resolved THz radiographs are generated in a frequency range from 0.1 to 2.2 THz at a spatial resolution up to 0.3 mm. THz waves cover a broad spectrum of applications ranging from the characterization of dielectric properties of non-metallic materials to the detection of the inner structure of improvised explosive devices (lEDs) that are currently being explored for suitability to NDT imaging techniques. This is discussed using an example of a mock-up letter bomb, and comparison is drawn to conventional X-ray radiographs. Since THz radiation is physiologically harmless it is favored for investigations of biological tissue e.g. for stand-off screening of persons at airports.