Study On Continuous Terahertz Imaging Technology And Its Application In Tumor Detection

Tumor is one of the most serious diseases harmful to human health,high precision imaging diagnostic instrument is an effective guarantee to obtain the best treatment effect.In particular,the accurate diagnosis technology of intraoperative tumor imaging has become a hot spot in current tumor diagnosis.Based on the security,penetrability,fingerprint and water absorption characteristics of terahertz(THz)wave,THz spectrum imaging has become a new detection technology for biomedical diagnosis.Continuous THz imaging system has the advantages of simple and fast imaging,and it’s one of the hot spots in biological tissue imaging research.The attenuated total reflection(ATR)imaging has high detection sensitivity,and the reflection imaging can realize deep tumor identification.In view problem of complex in vivo environment resulting in weak signal,low image contrast and poor imaging quality,the polarization characteristic,reflected signal and hydration mechanism of THz wave interacting with biological tissue were studied in this paper.High sensitivity imaging detection of continuous THz reflection and attenuated total reflection was achieved,and THz imaging of in vivo glioma and in vivo subcutaneous breast cancer was also obtained.The main content and innovation points are as follows:1.The interaction mechanism between THz wave and biological tissue was studied theoretically,and the detection model of biological tissue under different detection methods was established.Based on the dielectric model of THz wave interaction with biological tissue,the optical parameters of samples based on amplitude and phase information was studied.Continuous THz reflection and ATR imaging model were established and the reflectivity formula of sample based on intensity information was derived in detail.In addition,the detection principle of reflection and ATR imaging was also analyzed.2.A dual mode imaging method of reflection and attenuated total reflection was proposed.The influence factors of image resolution were studied and optimized.The image resolution of this system was up to 400 μm.Based on the reflection window and polarization mode optimization,the reflected signal was enhanced,and the image contrast was improved by 2.1 times.3.It was found that the imaging sensitivity of THz glioma was affected by temperature and THz frequency.The THz wave response characteristics of fresh brain glioma tissues in vitro at different temperatures and frequencies were studied.The results showed that the THz image contrast at 35℃ was increased by 3 times compared with that at-13℃.4.An in vivo glioma boundary identification method based on THz dual-mode imaging technology was proposed and realized.The result shows that the millimeter scale tumor can be identified.In vivo imaging detection of subcutaneous breast cancer in mice was achieved for the first time with a penetration depth of 460 μm.