Design of a multi-modality salpingoscope for visualization of the ovary and oviducts

Abstract

Recent discoveries suggest that ovarian cancer has its origins in the oviducts (Fallopian tubes) and may exist as intraepithelial carcinoma for up to 6 years. One route of access to the oviducts and ovaries is through the wall of the vagina. We have developed an approximately 3.8 mm diameter rigid salpingoscope for surveillance of high-risk women and early detection of ovarian cancer. The salpingoscope contains multiple advanced imaging modalities, as well as a channel for instillation of saline or dyes, and another channel for introduction of biopsy forceps. The single optical channel combines the modalities of multispectral fluorescence and reflectance wide-field imaging, multiphoton microscopy (MPM), and optical coherence tomography (OCT). Multiple modalities through a single channel are achieved by a novel lens system with dichroic coatings which create separate optical paths for visible wavelengths (low numerical aperture (NA) imaging) and near-infrared wavelengths (high NA imaging). A quartered piezoelectric tube actuator scans a dual-clad fiber with added mass to facilitate both relatively slow (OCT) and fast (wide field and MPM) scanning. Visible wavelength laser diodes are the source for wide field reflectance and fluorescence imaging, with remitted light collected through 12 high NA multimode fibers. A novel femtosecond laser with near-infrared output provides the source for OCT and MPM, with remitted light collected through the core and inner cladding of the dual-clad fiber, respectively. Detectors include high sensitivity photodiodes for wide field, a linear array with spectrometer for OCT, and photomultiplier tubes to collect two and three-photon signals for MPM imaging.