Bio-medical Applications of THz Imaging

We present examples of the application of THz time-domain imaging in the life-sciences and medical diagnosis. Since this new technique will have to compete with established techniques, we start with a comparative discussion of modern imaging systems followed by a brief description of a THz imaging setup. We then give three examples in the life sciences where THz imaging is potentially useful. First, we describe an examination of wood density variations due to tree rings and show that THz imaging can be a valuable tool for dendrochronologists. Second, we describe a study of water transport processes in plants. We investigated the slow rehydration process of drought-stressed plants and the fast water transport that occurs in mimosa after mechanical stimulus. Third, we describe an investigation of histopathological samples including the larynx of a pig and a human liver containing metastases, to explore the potential of THz imaging for medical diagnosis. In addition, we present the first continuous-wave THz imaging spectrometer employing a two-color external-cavity laser diode. This new THz imaging system is less expensive and more compact than traditional time-domain spectrometers.

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