A terahertz (THz) imaging system based on narrow band microbolometer sensors (NBMS) and a novel diffractive lens was developed for spectroscopic microscopy applications. The frequency response characteristics of the THz antenna-coupled NBMS were determined employing Fourier transform spectroscopy. The NBMS was found to be a very sensitive frequency selective sensor which was used to develop a compact all-electronic system for multispectral THz measurements. This system was successfully applied for principal components analysis of optically opaque packed samples. A thin diffractive lens with a numerical aperture of 0.62 was proposed for the reduction of system dimensions. The THz imaging system enhanced with novel optics was used to image for the first time non-neoplastic and neoplastic human colon tissues with close to wavelength-limited spatial resolution at 584 GHz frequency. The results demonstrated the new potential of compact RT THz imaging systems in the fields of spectroscopic analysis of materials and medical diagnostics.

Terahertz waves are sensitive to differences in biological tissue hydration, we present promising results regarding the feasibility of applying this with terahertz time-domain spectroscopy and imaging for early detection of cancer through the characterisation of human gastrointestinal tissue with cancer-affected regions. To do that, healthy (normal) and carcinoma-affected gastric tissue samples at different stages were measured using transmission terahertz time-domain spectroscopy in the frequency range of 0.15–2.00 THz. Absorption coefficients and refractive index spectra of both normal and carcinoma-affected tissue were extracted and analysed. The results confirm that the techniques may be powerful tools to perform qualitative, early diagnosis of human cancer.

Terahertz Spectroscopy for Gastrointestinal Cancer Diagnosis | InTechOpen, Published on: 2017-03-13. Authors: Faustino Wahaia, Irmantas Kašalynas, Gintaras Valušis, et