Advances in Terahertz Imaging
161
medical diagnosis of the structure of tooth, skin cancer and tumours, security imaging, inspection of semiconductor, food, pharmaceutical and very-high bandwidth
communications. Also, materials research and computing applications are gaining
attention.
5.1 Biomedical Applications
Already properties of terahertz radiation have been discussed that they have very low
photon energy, sensitivity to water and characteristic spectral signatures for many
substances. This makes THz imaging suitable for many biomedical applications. It
is already mentioned that owing to the non-ionizing character of terahertz radiation,
this is less harmful to living tissues than X-ray. This unique feature makes THz imaging an interesting candidate for medical applications including cancer diagnosis [2].
Imaging the structure of teeth and the identification of dental caries is another area
where terahertz imaging can be used as an alternative to other diagnostic technologies
[94]. Wound assessment is also another interesting application, where the terahertz
reflection pulse imaging technique can image skin through wound dressings [95].
Also, TPI has the potential to image both ductal carcinoma and invasive breast carcinomas, and this has been discussed by Pickwell and Wallace [4]. Using seven oral
tissues, oral cancer has been detected by terahertz imaging [96]. Different dental
tissues can also be distinguished by TPI and hence 3-D information can be gathered
[97, 98].
5.2 Security Applications
Active military research is underway to develop THz imaging for different security
applications. Specific security-related applications such as detecting illicit drugs [99–
101], weapons and explosive devices [102–105], including the important task of land
mine detection, are some potential applications of THz imaging. Though metallic
packages are opaque to THz waves, still dangerous concealed metallic weapons
like guns [106] or knives can be identified by their shapes using pattern recognition
algorithm. This is why at present it is not possible to completely substitute X-ray
scanners by THz spectrometers. But supplementary information about the sample
is provided by THz spectrometers. THz imaging can detect even liquid explosives
[37].
161
medical diagnosis of the structure of tooth, skin cancer and tumours, security imaging, inspection of semiconductor, food, pharmaceutical and very-high bandwidth
communications. Also, materials research and computing applications are gaining
attention.
5.1 Biomedical Applications
Already properties of terahertz radiation have been discussed that they have very low
photon energy, sensitivity to water and characteristic spectral signatures for many
substances. This makes THz imaging suitable for many biomedical applications. It
is already mentioned that owing to the non-ionizing character of terahertz radiation,
this is less harmful to living tissues than X-ray. This unique feature makes THz imaging an interesting candidate for medical applications including cancer diagnosis [2].
Imaging the structure of teeth and the identification of dental caries is another area
where terahertz imaging can be used as an alternative to other diagnostic technologies
[94]. Wound assessment is also another interesting application, where the terahertz
reflection pulse imaging technique can image skin through wound dressings [95].
Also, TPI has the potential to image both ductal carcinoma and invasive breast carcinomas, and this has been discussed by Pickwell and Wallace [4]. Using seven oral
tissues, oral cancer has been detected by terahertz imaging [96]. Different dental
tissues can also be distinguished by TPI and hence 3-D information can be gathered
[97, 98].
5.2 Security Applications
Active military research is underway to develop THz imaging for different security
applications. Specific security-related applications such as detecting illicit drugs [99–
101], weapons and explosive devices [102–105], including the important task of land
mine detection, are some potential applications of THz imaging. Though metallic
packages are opaque to THz waves, still dangerous concealed metallic weapons
like guns [106] or knives can be identified by their shapes using pattern recognition
algorithm. This is why at present it is not possible to completely substitute X-ray
scanners by THz spectrometers. But supplementary information about the sample
is provided by THz spectrometers. THz imaging can detect even liquid explosives
[37].