A DUAL-MODALITY OPTICAL BIOPSY APPROACH FOR IN VIVO DETECTION OF PROSTATE CANCER IN RAT MODEL

Abstract

Ultrasound-guided biopsy procedure for prostate cancer diagnosis, which is the current gold standard, involves quasi-random sampling of prostate tissue without any functional guidance. In this study, we discuss the possibility to augment the detection of prostate cancer using a dual-modality optical approach, which can be coupled with the current needle biopsy setup. Two techniques are light reflectance spectroscopy (LRS) that uses a broadband light source and a CCD array spectrometer, and auto-fluorescence lifetime measurement (AFLM) that uses a custom-designed, time-correlated single photon counting (TCSPC) system. Both LRS and AFLM were employed sequentially in this study to measure cancer tissue along with control tissue on a rat prostate tumor model. At an excitation wavelength of 447 nm, we investigated auto-fluorescence decay curves at the emission wavelengths of 532, 562, 632 and 684 nm for in vivo and ex vivo AFLM. These results show that auto-fluorescence lifetimes at all measured emission wavelengths differ between control and cancerous tissues with 100% specificity and sensitivity. Moreover, absolute values of hemoglobin derivatives and scattering coefficient were quantified using in vivo LRS. This part of study also demonstrates that light scattering and absorption are significantly different between the control and cancerous tissue. Overall, the study demonstrates that both LRS and AFLM may provide several intrinsic biomarkers for in vivo detection of prostate cancer.