Confocal fluorescence microendoscopy using a digital micro-mirror device

A design of confocal fluorescence microendoscopy utilizing a digital micro-mirror device (DMD) is described. Laser beams of the microendoscope are coupled into the body through a telescopic optics system, rather than through fibers or fiber bundles which are widely used in existing microendoscopes. Each micro-mirror of the DMD is used as a confocal pinhole. The DMD not only couples the laser beams into the body by a random time-varying speckle pattern and performs the scanning mechanism of the body tissue with different positions, but also couples the fluorescent signal emitted from the markers out to the CCD camera. Because of the CCD's integration feature and DMD's rapid parallel scanning feature, a complete predetermined depth tomography image accumulated by different scanning patterns of DMD can be acquired through only one CCD exposure procedure. The objective lens to realize high resolution and high sensitivity fluorescence imaging is the other function of the telescopic optics, with a numerical aperture of 0.35. The resolution of confocal microendoscope is superior to 228 lp/mm determined by 1951USAF resolution test target. Images of a tendon specimen are also shown to demonstrate practical application of the design. The confocal microendoscope using a DMD permits the acquisition of high-resolution real-time confocal images of epithelial tissue in vivo organ and realizes the aim of non-invasive diagnosis and treatment.