THz技术在中草药光谱检测及肿瘤诊断中的应用

发布时间：2018-04-28 06:59

本文选题：太赫兹时域光谱技术 + 太赫兹成像　；参考：《中央民族大学》2017年硕士论文

【摘要】：太赫兹时域光谱技术(THz-TDS)是20世纪80年代以来新发展起来的一种技术,利用光电导的方法产生THz辐射脉冲,具有带宽大、信噪比高、能够在室温中工作等优点。THz脉冲透射样品或者在样品表面发生反射,测量THz电场强度与时间的变化关系,对测得的数据进行经傅里叶变换后得到频域上幅值与相位的变化关系,从而获得样品的信息。太赫兹技术凭借其独特的优势在中草药的质量检测、定性定量和光谱成像分析中得到广泛的应用。本文主要利用THz-TDS技术和光谱成像技术在中草药光谱检测及肿瘤诊断方面做了如下几个部分的工作:首先,利用太赫兹时域光谱技术对不同含水量的天麻及不同铬含量的明胶样品分别进行了测量,得到其THz光谱,分别计算获得天麻脱水过程中与频率相关的吸收系数曲线,及不同铬含量明胶与频率相关的吸收系数曲线。发现含水量与吸收系数、明胶中铬含量与吸收系数都呈线性正相关的关系,从而根据测量的结果对样品的质量进行评估。其次,利用太赫兹时域光谱技术重新检测了青蒿素及其衍生物(双氢青蒿素、青蒿琥酯、蒿甲醚)等四种青蒿素类药物在太赫兹波段的吸收特性,分别得到它们在特定波段(0.2-2.7THz)的吸收光谱。并对实验结果与现有的指纹谱数据进行了对比分析。结果显示,绝大部分的共振峰与文献[24]中的一致,但峰位和强度略有差异,并且有新的峰位出现。然后,讨论了样品制备和数据处理方法对数据结果的影响,以及分子结构与峰位的关系。并基于此进一步确认了数据的有效性。结果为进一步研究青蒿素及其衍生物的药性提供参考,并对其无损鉴别、定量定性分析提供了一种快速高效的鉴定方法。最后,运用太赫兹时域光谱成像技术对肝脏正常组织与肝脏肿瘤组织、肾脏正常组织与肾脏肿瘤组织分别进行探测,分别得到了他们的太赫兹时域光谱图,经数据处理得到了肿瘤组织与正常组织的吸收系数光谱图,并对正常组织与肿瘤组织的吸收光谱分别进行了分析。然后利用逐点扫描太赫兹成像系统分别对肝脏、肾脏的肿瘤组织进行了成像,分别得到它们在时域显示模式和频域显示模式下的THz重构图,成像结果能较好区分出肿瘤组织与正常组织。最后,对成像结果进行了讨论,提出了实验过程中出现的问题,并针对已有的问题提供了解决的办法,为以后太赫兹技术在肿瘤诊断领域的研究奠定了基础。
[Abstract]:Terahertz time-domain spectroscopy (THz-TDS) is a new technology developed since 1980s. It uses photoconductive method to generate THz radiation pulse, which has a large bandwidth and high signal-to-noise ratio (SNR). It can work at room temperature and other advantages. THz pulse transmission samples or on the surface of the sample reflect, measure the change of THz electric field intensity and time, and get the change of amplitude and phase in frequency domain by Fourier transform. In order to obtain the sample information. Terahertz technology has been widely used in the quality detection, qualitative and quantitative analysis and spectral imaging analysis of Chinese herbal medicine with its unique advantages. In this paper, THz-TDS and spectral imaging techniques are used in the detection of Chinese herbal medicine spectrum and tumor diagnosis as follows: first, The THz spectra of Gastrodia elata and gelatin samples with different water content and different chromium content were measured by terahertz time-domain spectroscopy. The absorption coefficient curves related to frequency in the dehydration process of Gastrodia elata were calculated, respectively. And the absorption coefficient curve of different chromium content gelatin and frequency correlation. It was found that there was a linear positive correlation between water content and absorption coefficient, chromium content in gelatin and absorption coefficient, so the quality of the sample was evaluated according to the measured results. Secondly, the absorption characteristics of artemisinin and its derivatives (dihydroartemisinin, artesunate, artemisinin) in terahertz band were re-examined by THz time-domain spectroscopy. Their absorption spectra of 0.2-2.7 THZ were obtained respectively. The experimental results are compared with the existing fingerprint data. The results show that most of the resonance peaks are consistent with those in literature [24], but the peak position and intensity are slightly different, and new peaks appear. Then, the influence of sample preparation and data processing on the data results and the relationship between molecular structure and peak position are discussed. Based on this, the validity of the data is further confirmed. The results provided a rapid and efficient method for further study of artemisinin and its derivatives, nondestructive identification and quantitative qualitative analysis of artemisinin and its derivatives. Finally, terahertz time-domain imaging technique was used to detect normal liver tissue and liver tumor tissue, kidney normal tissue and renal tumor tissue, and their terahertz time-domain spectra were obtained. The absorption coefficient spectra of tumor and normal tissues were obtained by data processing, and the absorption spectra of normal and normal tissues were analyzed respectively. Then the liver and kidney tumor tissues were examined by point-by-point scanning terahertz imaging system, and their THz reconstructed images in time-domain and frequency-domain display modes were obtained, respectively. The imaging results can distinguish tumor tissue from normal tissue. Finally, the imaging results are discussed, the problems in the experiment are put forward, and the solutions to the existing problems are provided, which will lay a foundation for the future research of terahertz technology in the field of tumor diagnosis.
【学位授予单位】：中央民族大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R284;R730.4;O657.3

【参考文献】