Dual Modality Optical Coherence Tomography and Multispectral Fluorescence Imaging for Ovarian Cancer Detection

摘要

Ovarian cancer is the deadliest gynecologic cancer for women. Diagnosis at the local stage leads to 91% 5-year survival rates, but only 15% of cases are detected early. Existing screening methods have proven ineffective in large clinical trials. Screening is complicated by the heterogeneity of the disease with multiple types of ovarian cancer originating both on the ovary and in the fallopian tube. Early stage cancer is too subtle for non-invasive imaging techniques such as ultrasound or magnetic resonance imaging. This study evaluates the feasibility and design of dual modality, multispectral fluorescence imaging (MFI) and optical coherence tomography (OCT) endoscopes for improved ovarian cancer screening. The study is broken up into three sections. In the first study MFI is validated in an ex vivo imaging study of human ovarian and fallopian tube tissue samples. Tissue autofluorescence excited by ultraviolet and blue wavelengths is shown to be a promising discriminator between normal and cancerous tissue. The second study combines OCT and MFI into a sub millimeter diameter endoscope designed to screen for ovarian cancer by screening inside the fallopian tube and at the ovary. The small size is required for screening the full length of the fallopian tube. MFI is implemented as a wide-field navigational imaging technique with high sensitivity complemented by high resolution structural depth imaging of OCT over a limited field of view. The final study presents a novel lens design for a scanning fiber endoscope with forward-viewing navigation and side-viewing OCT. A piezo tube is used to scan an optical fiber providing both the navigation channel’s illumination and OCT imaging. The design spatially separates the forward-viewing illumination from the OCT. As the piezo fiber circularly scans at its maximum deviation the OCT beam focus is rotationally scanned out the side of the endoscope tip by a rotationally symmetric double reflection in the cover plate.