Abstract-Optimization for vertically scanning terahertz attenuated total reflection imaging

Hongxiang Liu, Yuye Wang, Degang Xu, Zhinan Jiang, Jining Li, Limin Wu, Chao Yan, Longhuang Tang, Yixin He, Dexian Yan, Xin Ding, Hua Feng, and Jianquan Yao

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-16-20744

Terahertz attenuated total reflection imaging has been used to develop preliminary applications without any in-depth analysis of the nature of present systems. Based on our proposed vertically scanning imaging system, an analysis of optimum prism design and polarization selection for error reduction is presented theoretically and experimentally, showing good agreement. By taking the secondary reflection inside the prism and the prism deflection into consideration, p-polarized terahertz waves are recommended for prisms with a base angle below 31°, leading to minimum error. This work will contribute to the development of more practical application of terahertz attenuated total reflection scanning imaging in various fields with enhanced performance.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Automatic evaluation of traumatic brain injury based on terahertz imaging with machine learning

Jia Shi, Yuye Wang, Tunan Chen, Degang Xu, Hengli Zhao, Linyu Chen, Chao Yan, Longhuang Tang, Yixin He, Hua Feng, and Jianquan Yao

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-5-6371

The imaging diagnosis and prognostication of different degrees of traumatic brain injury (TBI) is very important for early care and clinical treatment. Especially, the exact recognition of mild TBI is the bottleneck for current label-free imaging technologies in neurosurgery. Here, we report an automatic evaluation method for TBI recognition with terahertz (THz) continuous-wave (CW) transmission imaging based on machine learning (ML). We propose a new feature extraction method for biological THz images combined with the transmittance distribution features in spatial domain and statistical distribution features in normalized gray histogram. Based on the extracted feature database, ML algorithms are performed for the classification of different degrees of TBI by feature selection and parameter optimization. The highest classification accuracy is up to 87.5%. The area under the curve (AUC) scores of the receiver operating characteristics (ROC) curve are all higher than 0.9, which shows this evaluation method has a good generalization ability. Furthermore, the excellent performance of the proposed system in the recognition of mild TBI is analyzed by different methodological parameters and diagnostic criteria. The system can be extensible to various diseases and will be a powerful tool in automatic biomedical diagnostics.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-PAPER High-sensitivity attenuated total internal reflection continuous-wave terahertz imaging

Hongxiang Liu1,2,4, Yuye Wang1,2,3,4, Degang Xu1,2, Limin Wu1,2, Chao Yan1,2, Dexian Yan1,2, Longhuang Tang1,2, Yixin He1,2, Hua Feng3 and Jianquan Yao

http://iopscience.iop.org/article/10.1088/1361-6463/aa7d9a/pdf

We demonstrate an attenuated total internal reflection imaging system. The surface information of the sample on top of a prism can be acquired by two-dimensionally scanning this prism moving in the vertical plane with horizontally incident continuous terahertz waves at a fixed height. The principles and feasibility of this method are investigated. The effective imaging area on the prism, image resolution and polarization dependence of contrast enhancement and stability improvement are analyzed. Examples including solid agar, distilled water and porcine tissue are presented, demonstrating the method's advantages of high sensitivity and simple sample preparation. The experimental and theoretical results consistently show that p-polarization contributes to enhanced image contrast and more stable intensity of the attenuated total internal reflected signal.

Abstract-Terahertz pulsed spectroscopy of paraffin-embedded brain glioma

Kun Meng ; Tu-nan Chen ; Tao Chen ; Li-guo Zhu ; Qiao Liu ; Zhao Li ; Fei Li; Sen-cheng Zhong ; Ze-ren Li ; Hua Feng ; Jian-heng Zhao

[-] Author Affiliationshttp://biomedicaloptics.spiedigitallibrary.org/article.aspx?articleid=1887716

Kun Meng

China Academy of Engineering Physics, Institute of Fluid Physics, Interdisciplinary Laboratory of Physics and Biomedicine, No. 64, Mianshan Road, Mianyang, Sichuan 621900, China

China Academy of Engineering Physics, Terahertz Research Center, Mianyang, Sichuan 621900, China

Tu-nan Chen

China Academy of Engineering Physics, Institute of Fluid Physics, Interdisciplinary Laboratory of Physics and Biomedicine, No. 64, Mianshan Road, Mianyang, Sichuan 621900, China

Third Military Medical University, Southwest Hospital, Department of Neurosurgery, No. 30, Gaotanyan Street, Shapingba, Chongqing 400038, China

Tao Chen, Jian-heng Zhao

China Academy of Engineering Physics, Institute of Fluid Physics, Interdisciplinary Laboratory of Physics and Biomedicine, No. 64, Mianshan Road, Mianyang, Sichuan 621900, China

Li-guo Zhu, Qiao Liu, Sen-cheng Zhong, Ze-ren Li

China Academy of Engineering Physics, Institute of Fluid Physics, Interdisciplinary Laboratory of Physics and Biomedicine, No. 64, Mianshan Road, Mianyang, Sichuan 621900, China

China Academy of Engineering Physics, Terahertz Research Center, Mianyang, Sichuan 621900, China

Zhao Li, Fei Li, Hua Feng

Third Military Medical University, Southwest Hospital, Department of Neurosurgery, No. 30, Gaotanyan Street, Shapingba, Chongqing 400038, China

J. Biomed. Opt. 19(7), 077001 (Jul 07, 2014). doi:10.1117/1.JBO.19.7.077001

History: Received April 11, 2014; Revised June 4, 2014; Accepted June 13, 2014

Text Size: A A A

 Open Access

Abstract.  The refractive indices, absorption coefficients, and complex dielectric constants of paraffin-embedded brain glioma and normal brain tissues have been measured by a terahertz time-domain spectroscopy (THz-TDS) system in the 0.2- to 2.0-THz range. The spectral differences between gliomas and normal brain tissues were obtained. Compared with normal brain tissue, our results indicate that paraffin-embedded brain gliomas have a higher refractive index, absorption coefficient, and dielectric constant. Based on these results, the best THz frequencies for different methods of paraffin-embedded brain glioma imaging, such as intensity imaging, coherent imaging with continuum THz sources, and THz pulsed imaging with short-pulsed THz sources, are analyzed.

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