Applications Of Terahertz Technology In Medical Field

Terahertz (THz) technology, a kind of emerging spectrum technologies, has developed rapidly in recent years, received increasingly attention from the scientific community and industry, and showed great potential applications in the field of aerospace, security checks, and medicine. In the field of medical science, the vibrational frequencies of many biological macromolecules landed in THz wave band, and THz technology is thus expected to become the effective means to identify the biological macromolecules and to control the quality of product. Also, Terahertz waves, whose energy is much smaller than x rays, can penetrate biological tissue and will not cause ionization of biological samples. Meanwhile, the THz spectrum of cancerous tissue has certain characteristics. Therefore, terahertz imaging has broad application prospects in the diagnosis and treatment of cancer and nondestructive testing biological tissues.This thesis mainly introduces the applications of the terahertz technology in medical field, including the identification of amino acids, the characterization of azithromycin drugs with different physical forms and the diagnosis of cancer tumor of organization. The results are as follows:Firstly, the low-frequency, vibrational spectra of13pairs of amino acids enantiomers were measured in the range of0.2-3.0THz (6.6-100.0cm-1) at room temperature. Although all of their structural properties are identical except mirror images of each other, the spectra of three samples in every group are quite different in both absorption band positions and their relative intensities, especially for L-, D-histidine, L-, D-isoleucine and L-, D-serine. Such high-resolution THz fingerprint spectra and their chiral comparisons provide a rapid, nondestructive and reliable method for the identification of the L-as well as D-amino acids.Secondly, by detecting the THz spectra of different forms of azithromycin drugs with different forms and different manufacturers, we found that exotic azithromycin suspension has characteristic peaks in1.46THz,1.84THz and2.40THz, and domestic azithromycin capsule, tablet and dispersible tablet have corresponding peaks in the vicinity, among of which tablet has the worst obvious characteristic peaks and this is because in the production process tablet need be dissolved in water, affecting its molecular structure and conformation. In addition, we also have investigated the THz spectroscopy of different concentrations of azithromycin/polyethylene sheet and found that the vibrational frequencies at1.45THz and1.83THz showed positive linear correlation relationship between concentration and absorption intensity, and it is more obvious for frequency at1.83THz. Therefore, we can presumed the concentration of active ingredient in return according to the result of the measurement, and thus identifying the quality of the drug.Finally, using THz-TDS and terahertz imaging technology, we have imaged the normal and tumor tissues of the liver and lungs, respectively. Based on the relevant experience from the THz spectral detection and imaging measurements of liver, we get significant results on the THz imaging of lung cancer tissue in the range of1.0THz-1.75THz. We can clearly distinguish the normal tissue and tumor tissue by the point-to-point THz puls imaging, and the higher the frequency we selecting within the range, the higher imaging resolution can be achieved.