Department of Pathology, Iwate Medical University School of Medicine, Morioka, Japan.
Tohoku J Exp Med. 2011 Apr;223(4):291-6. doi: 10.1620/tjem.223.291.
Terahertz (THz; 10(12) Hz) waves have a frequency from 0.1 to 10 THz between the visible light and microwave domains. THz waves are expected to be useful for analysis of the histological features, without any staining procedure that is an indispensable prerequisite for optical microscopy. It has been demonstrated that THz transmittances at cancer and normal tissues are different. However, spectroscopy that is currently used is applicable for imaging only small areas at fixed-wavelength. In this study, we have developed a spectrometer employing a gallium phosphide (GaP) THz-generator and applied it to examine large areas of tissue specimens using a wide range of wavelengths. We thus examined the whole areas of two paraffin sections (metastatic liver cancer and acute myocardial infarction) in a frequency range of 1 to 6 THz, and compared the THz images of ordinary paraffin sections with the histological features detected by microscopy. THz imaging showed striking contrasts between cancerous and non-cancerous regions at 3.7 THz. Likewise, the precise imaging was achieved in the infarct myocardium at 3.6 THz. Images of THz transmittances in optimal wavelength were well matched with HE histological features both in cancer and myocardial tissues. Cancer regions showed higher transmittance than non-cancerous regions in liver. Old scar regions showed low transmittance, and necrotic regions showed relatively higher transmittance than normal myocardial areas. Thus, THz imaging precisely reflects tissue conditions such as tumor, non-tumor tissues, tissue degeneration and fibrosis. The newly established THz spectroscopy would be useful for pathological diagnosis of routinely processed specimens.
太赫兹（THz；10(12) Hz）波的频率位于可见光和微波区域之间，为 0.1 到 10 THz。THz 波有望用于分析组织学特征，而无需进行光学显微镜必不可少的染色程序。已经证明，癌症组织和正常组织的 THz 透射率不同。然而，目前使用的光谱学仅适用于在固定波长下对小区域进行成像。在这项研究中，我们开发了一种采用磷化镓（GaP）太赫兹发生器的光谱仪，并应用它在大范围波长下检查组织标本的大面积。因此，我们在 1 到 6 THz 的频率范围内检查了两个石蜡切片（转移性肝癌和急性心肌梗死）的整个区域，并将普通石蜡切片的太赫兹图像与显微镜检测到的组织学特征进行了比较。在 3.7 THz 处，太赫兹成像显示出癌症和非癌区域之间的明显对比。同样，在 3.6 THz 处也实现了精确的心肌梗死成像。最佳波长的太赫兹透射率图像与癌症和心肌组织的 HE 组织学特征非常匹配。在肝脏中，癌症区域的透射率高于非癌区域。旧疤痕区域的透射率较低，而坏死区域的透射率比正常心肌区域相对较高。因此，太赫兹成像精确地反映了组织状况，如肿瘤、非肿瘤组织、组织退化和纤维化。新建立的太赫兹光谱学将有助于对常规处理的标本进行病理诊断。
