| Gastric cancer is one of the most common cancers and has a lower survival rate in malignant tumors.The cure rate of operation for early gastric cancer is very high,as a result,early diagnosis of gastric cancer is of great significance for the treatment of cancer.However,due to the occult and diversity of early gastric cancer,there are still misdiagnosis in clinical practice.Therefore,to develop a new detection method has great potential applications in clinical cancer detection.Terahertz(THz)wave has unique optical characteristics with high penetrability and low energy,and it is a kind of non free radiation with coherence,transient and broadband.Many biological macromolecules have unique "fingerprint characteristics" in this frequency band.Based on these characteristics,THz wave has been proved to be suitable for detection of human cancers.Different tissues have distinctive absorption characteristics at THz range,which makes THz radiation an effective tool for qualitative identification of different biological tissues.At present,terahertz time domain spectroscopy system(THz-TDS)and terahertz pulsed imaging(TPI)are traditional research methods in tissue differentiation.Previous studies have proved that THz technologies can well identify biological tissues with different properties and demarcate the boundary of cancer tissues.In order to further study the promising and popular THz detection technology,we take the gastric tissue as the detection object to confirm the great prospect of THz technology in the biomedical field.The work mainly includes the following aspects:(1)In this work,34 paraffin-embedded gastric tissues were used including 12 normal tissues,10 precancerous tissues,and 12 cancer tissues.Each tissue sample is divided into two parts,one for pathological H&E staining and the other for THz-TDS measurement.The results proved that the THz absorption spectra can successfully distinguish tissues with cancer or precancerous tissues from normal tissues,even cancer with carcinoma in situ.Moreover,the absorption coefficient of the cancer tissue is greater than precancerous tissue,and the normal tissue is the least.The sensitivity and specificity of using THz-TDS to diagnose gastric cancer tissue with no other methods are also confirmed to be both 100% by a comparative experiment between THz assay and pathologic H&E staining examinations in an additional group of 20 samples.(2)THz near-field imaging system was used to diagnose 7 human gastric tissues at 0.32 THz.The results show that THz images can distinguish the boundary between tumor tissue and normal tissue.In addition,according to the different absorption coefficient,the tumor area can be accurately calibrated. |
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