Horizontal-scanning attenuated total reflection terahertz imaging for biological tissues

Limin Wu; Degang Xu; Yuye Wang; Yingying Zhang; Hanjie Wang; Bin Liao; Sheng Gong; Tunan Chen; Nan Wu; Hua Feng; Jianquan Yao

doi:10.1117/1.NPh.7.2.025005

Horizontal-scanning attenuated total reflection terahertz imaging for biological tissues

Neurophotonics. 2020 Apr;7(2):025005. doi: 10.1117/1.NPh.7.2.025005. Epub 2020 Jun 13.

Authors

Limin Wu^{1

2}, Degang Xu^{1

2}, Yuye Wang^{1

2}, Yingying Zhang³, Hanjie Wang³, Bin Liao⁴, Sheng Gong⁴, Tunan Chen⁴, Nan Wu⁴, Hua Feng⁴, Jianquan Yao^{1

2}

Affiliations

¹ Tianjin University, Institute of Laser and Optoelectronics, School of Precision Instruments and Optoelectronic Engineering, Tianjin, China.
² Tianjin University, Key Laboratory of Optoelectronics Information Technology (Ministry of Education), Tianjin, China.
³ Tianjin University, School of Life Sciences, Tianjin Engineering Center of Micro-Nano Biomaterials and Detection-Treatment Technology, Tianjin, China.
⁴ Third Military Medical University (Army Medical University), Southwest Hospital, Department of Neurosurgery and Key Laboratory of Neurotrauma, Chongqing, China.

Abstract

Significance: Terahertz wave is a potential tool for biological tissues due to its noninvasiveness and high sensitivity to water. Attenuated total reflection (ATR) with the characteristics of high sensitivity and nondestruction has been applied for THz imaging. Aim: We aim to develop an imaging methodology to facilitate practical application of THz ATR imaging. Approach: We have demonstrated a horizontally scanning THz continuous wave ATR imaging system. The effective imaging area was as large as the prism imaging surface by optimizing the ATR prism, and the influence of secondary reflection can be well avoided. By taking the image resolution and stability of this system into consideration, the incident angle $α$ to the prism bottom was chosen to be 30 deg. Results: The image resolution of this system can be up to 400 and $450 μ m$ in horizontal and vertical directions, respectively. Furthermore, U87-glioma regions of mice brain tissues with different sizes and C6-glioma regions of rat brain tissues with relatively large size can be differentiated clearly from normal brain tissues by this imaging system. The volume and location of the tumor region shown in the THz images are similar to those visualized macroscopically in the corresponding visual and H&E-stained images. Conclusion: We indicate terahertz horizontal-scanning ATR imaging technique with large effective imaging area, and high resolution could be used as an alternative method for label-free and high-sensitivity imaging of biological tissues.

Keywords: attenuated total reflection; brain tumor; terahertz imaging; terahertz wave.

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