Toward development of a large field-of-view cancer screening patch (CASP) to detect cervical intraepithelial neoplasia.

Cervical cancers are primarily diagnosed via colposcopy, in which the tissue is visually assessed by a clinician for abnormalities, followed by directed biopsies and histologic analysis of excised tissue. Optical biopsy technologies offer a less invasive method of imaging such that subcellular features can be resolved without removing tissue. These techniques, however, are limited in field-of-view by the distal end of the probe. We present a prototype that incorporates a rigid, machinable waveguide that is in direct contact with a fluorescently-labeled sample paired with a scanning fluorescent microscope. The system is capable of imaging large areas of tissue without the need to re-position the tissue-probe interface. A mosaicing algorithm was developed to quantify scanning shifts and stitch neighboring frames together to increase the field-of-view. Our prototype can yield a maximum axial resolution of <5 µm for individual frames and can produce mosaiced images with a field-of-view greater than 15 mm x 15 mm without sacrificing resolution. We validated the system with a 1951 USAF resolution target, fluorescent in vitro standards, and a patient study where