[OPTICAL REVIEW Vol. 13, No. 4 (2006) 201-206]
© 2006 The Optical Society of Japan

Range Technique in Scattering Medium Using a Needle-Fiber Optical Coherence Tomography System

Tingyu LI, Kouichi NITTA, Osamu MATOBA and Takeaki YOSHIMURA

Department of Computer and Systems Engineering, Faculty of Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan

(Received February 6, 2006; Accepted April 14, 2006)

A needle-fiber optical coherence tomography (OCT) system designed for guiding epidural anesthesia to a target is presented. In the preliminary experiment, a desired target in tofu as a strong scattering medium can be monitored over a sufficient range of several millimeters within a short measuring time. The axial resolution is 21 μm. In order to investigate the ranging performance, the relation between background noise levels and focus-scattering properties in a confocal optical system is numerically studied by use of Monte Carlo technique. Numerical results indicate that an appropriate focal length of the lens attached to the fiber should be used to separate the OCT signal from strong noise in strongly scattered medium.

Key words: needle-fiber system, range technique, optical coherence tomography, Monte Carlo simulation, epidural anesthesia