In recent years, Terahertz Time-domain Spectroscopy (THz-TDS) technology have been more applied in the medical diagnose research. Because the vibrational levels of bio-macromolecules march within THz frequency range, so that THz-TDS technique can be used to study medical practice as tissue information and a number of THz imaging techniques will become an effective novel way to study biological tissue and to reveal the characteristics of cancerous tissue at the molecular level. To a certain degree, this new type of spectroscopic technique is similar to Fourier Infrared Spectroscopy in theory. However, compare with traditional pathology, THz-TDS can provide a quick and nondestructive medical result and it is more sensitive to cancer tissues during the earlier diagnosis period.This paper show Terahertz Spectroscopy Transmission Image used in Skin Cancerous Tissue Diagnose in theory analyse and experiment study, to validate potential application of THz-TDS, especially in medical diagnostics. THz-TDS laboratory setup have been improved which of automatic scanning controlled by motor have been made to instead of original manual operate. Also the mechanical structure of two-dimensional translation stage have been redesigned and processed. The THz-TDS spectrums of normal human skin tissue and cancerous tissue are obtained by THz-TDS transmission way. Firstly, the outline and the general lesion areas of the sample are described by imaging with the time-domain data. Then the frequency domain signal is obtained by FFT, and the THz absorption curve is obtained by calculating. Therefore, these obvious absorption peaks of skin tumor at 1.35, 1.65 and 2.2THz in frequency range. These images of the samples which are formed respectively by these three power absorption coefficients. Specially the absorption frequency of skin tumor at 1.35 and 1.65THz are sensitiver than other. Therer are some area being higher power absorption coefficient, where are same ones accord with results of pathological diagnosis, but there is differ from at 2.2THz frequency domain. The results show that THz wavelength should be controlled below 2.2 THz during the diagnosis of skin tissue. We study spectrums of normal human skin tissue and cancerous tissue. In viwes the sensitivity of terahertz radiation to polar molecules of water is very high, biological tissues with high level of hydration show strong absorption at terahertz frequencies. And the cancerous tissue is higher water content than normal ones. However, in this work, we specifically address the questions of the relative contributions of different water content and component changes of cancerous tissue. The research indicates the feasibility of THz-TDS in the area of bio-medical diagnosis.
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