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Proceedings Paper

1-mm catheterscope
Author(s): Eric J. Seibel
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Paper Abstract

Flexible endoscopes use one sensor element per display pixel. When diameter is reduced to the size of a catheter, there is a significant reduction in the number of pixels within the image. By placing a sub-millimeter microscanner at the tip of a catheter, image quality can be significantly improved. The microscanner consists of a 0.4 mm diameter piezoelectric tube with quadrant electrodes, surrounding a cantilevered singlemode optical fiber. At the distal end, the fiber microscanner is sealed with a 0.9 mm diameter lens assembly, creating a rigid length less than 10 mm at the tip of a highly flexible shaft. The cantilevered fiber is vibrated at the first mode of resonance for bending to generate a circular scan pattern. A spiral scan pattern is generated that constitutes an image frame by modulating the piezoelectric drive signals. By using a custom optical fiber at 80 microns cladding diameter, >10 KHz resonant scanning is achieved, resulting in a 30 Hz frame rate. Red (635 nm), green (532 nm), and blue (442 nm) laser light is scanned by coupling to the fiber scanner. The scanned illumination is detected in a non-confocal arrangement by having one or more optical fibers collecting the backscattered light at MHz pixel rates. Current 1-mm diameter catheterscopes generate 500-line images at maximum fields of view of 100 degrees and spatial resolutions of <20 microns with image zooming. Shaft length of four meters have been fabricated with flexibility of <10 mm bending radius to image previously inaccessible regions of the body.

Paper Details

Date Published: 7 February 2008
PDF: 8 pages
Proc. SPIE 6852, Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications VIII, 685207 (7 February 2008); doi: 10.1117/12.765983
Show Author Affiliations
Eric J. Seibel, Univ. of Washington (United States)

Published in SPIE Proceedings Vol. 6852:
Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications VIII
Israel Gannot, Editor(s)

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