Development of a fiber-optic confocal microendoscope for clinical endoscopy

A confocal microendoscope has been developed to examine cellular pathology during optical biopsy. The system employs a flexible fiber optic catheter coupled to a slit-scan confocal microscope to image tissue at remote locations in the body. The catheter of the confocal microendoscope consists of a fiber-optic imaging bundle, a miniature objective, and a miniature focusing mechanism. The system has a lateral resolution of 1.8mum and an axial resolution of 25mum. The confocal microendoscope can operate in a grayscale or multi-spectral imaging mode. Extensive work has been done to design a new miniature objective and focusing mechanism that will allow the catheter to be routed through the therapeutic channel of a clinical endoscope. We present the design for a miniature F/1 achromatic objective with nearly diffraction limited performance. The objective will be coupled to a pneumatic focusing mechanism to provide focus control to 200mum below the surface of the tissue. The new catheter has an overall diameter of 3mm with a rigid tip of only 20mm in length.