Characterization Of Ovarian Cancer Tissues Based On Terahertz Spectroscopy Technology

Ovarian cancer is the most lethal gynecological tumor that is extremely harmful to women’s health.Current ovarian cancer diagnostic methods mainly include the detection of serum biomarkers,and imaging examinations such as ultrasonography and computed tomography(CT).These diagnostic techniques show some limitations in certain respects.For example,serum biomarkers lack sufficient specificity and sensitivity,and ultrasound screening may lead to false positive.It is of great significance to develop novel techniques for ovarian cancer detection.Terahertz(THz)wave has significant potential in biomedical diagnosis for its unique properties of fingerprint spectrum and noninvasive and nonionizing properties to living organisms.THz technology has been used for the label-free identification and detection of skin cancer,gastrointestinal cancer,breast cancer,etc.Here,a transmitted continuous-wave THz spectroscopy system was used to measure 3 groups of human cancerous and normal ovarian tissues.Fresh tissue samples were made into paraffinembedded tissue sections with a thickness of 1-2 mm,to remove the strong absorption of terahertz waves from the tissue water.With the same thickness of samples in the same group,we obtained the THz spectra of normal and cancerous ovarian tissues in the range of 0.4-1.5 THz.The results indicate that in all three groups measured,cancerous ovarian tissues have a higher terahertz absorption compared with normal ones.The THz absorption peaks of cancerous and normal ovarian tissues mainly locate in the range of 0.5-0.8 THz.It is noted that some absorption peaks of normal ovarian tissue(0.588 THz,0.748 THz and 0.812 THz)get weaker and even disappear in the transmittance line of serous ovarian cancer tissue while some others especially absorption peak in 1.396 THz get enhanced.Furthermore,we obtained the typical hematoxylin and eosin(HE)stained microscope images of cancerous and normal ovarian tissues,and found that there are obvious variations in tissue structure,morphology and size of cell nuclear,between normal and cancerous ovarian tissues.This may be the biological reason for the difference in terahertz spectra of the two types of tissues.Split-ring resonator(SRR)based sensors at the microwave or terahertz regime can achieve high-sensitivity,label-free biological detection.The resonant frequency of SRR-based sensor will shift differently for normal and cancerous ovarian tissues have different dielectric constants.In this paper,a spoof surface plasmon polariton sensor with SRR was used to differentiate normal and cancerous ovarian tissue.Compared to the resonant frequency of this sensor(53.980 GHz),when measuring normal and cancerous ovarian tissue,the average resonant frequencies are 53.890 GHz(normal tissue),53.768 GHz(serous ovarian cancer tissue)and 53.777 GHz(clear cell carcinoma),separately.This demonstrates that the shift of resonance frequency caused by ovarian cancer tissue is greater than that by normal ones.The results show that for normal ovarian tissue,the resonant frequencies are mainly located in the range of 53.852-53.915 GHz,while the range is 53.722-53.798 GHz for serous ovarian cancer and 53.750-53.800 GHz for ovarian clear cell carcinoma.In conclusion,continuous-wave THz spectroscopy technology and SRR-based biosensing technology were used for the characterization of ovarian cancer tissues here.Our preliminary results demonstrate the potential of continuous-wave THz spectroscopy technology for label-free ovarian cancer detection,and the SRR-based sensor is expected to be used for high-sensitivity,label-free ovarian cancer recognition.