A confocal fiber optic catheter for in vivo thickness measurement of biological tissues

A fiber optic catheter with a MEMS (Microelectromechanical Systems) scanning microlens is demonstrated in this paper. Biological tissue thickness measurement using confocal scanning is presented. The catheter has an outer diameter and a rigid length of 4.75 mm and 30 mm respectively. Thickness of biological tissue is measured by out-of-plane actuation of the microlens using a micro magnetic actuator and collecting the intensity of the reflected light from the tissue. Scanning is performed at the resonant frequency, eliminating signal artifacts due to the external vibrations and patient´s involuntary movements. To demonstrate the functionality of the confocal scanner, cornea and skin thicknesses of a 5-months-old female C3H/HeN mouse were measured and compared with histology images.