Based on the reflection-type polarization measurement of second-harmonic-generation (SHG) light induced by collagen molecules, we are able to determine the collagen fiber orientation in human tissues taken from a cadaver. The resulting SHG radar graph shows the direction of the absolute orientation and the degree of organization of collagen fibers. To evaluate the probing sensitivity to the collagen orientation, we compared the proposed method with other polarimetric methods. Use of the proposed method revealed characteristic orientation differences among collagen fibers and demonstrated significant inhomogeneity with respect to the distribution of collagen orientation in human dentin. The proposed method provides a powerful research and diagnostic tool for examining the collagen orientation in human tissues.
© 2004 Optical Society of America
(120.5410) Instrumentation, measurement, and metrology : Polarimetry
(140.7090) Lasers and laser optics : Ultrafast lasers
(170.3890) Medical optics and biotechnology : Medical optics instrumentation
(170.4580) Medical optics and biotechnology : Optical diagnostics for medicine
(170.6510) Medical optics and biotechnology : Spectroscopy, tissue diagnostics
Takeshi Yasui, Yoshiyuki Tohno, and Tsutomu Araki, "Determination of Collagen Fiber Orientation in Human Tissue by Use of Polarization Measurement of Molecular Second-Harmonic-Generation Light," Appl. Opt. 43, 2861-2867 (2004)