title: Single-wavelength reflected confocal and multiphoton microscopy for tissue imaging.
abstract: Both reflected confocal and multiphoton microscopy can have clinical diagnostic applications. The successful combination of both modalities in tissue imaging enables unique image contrast to be achieved, especially if a single laser excitation wavelength is used. We apply this approach for skin and corneal imaging using the 780-nm output of a femtosecond, titanium-sapphire laser. We find that the near-IR, reflected confocal (RC) signal is useful in characterizing refractive index varying boundaries in bovine cornea and porcine skin, while the multiphoton autofluorescence (MAF) and second-harmonic generation (SHG) intensities can be used to image cytoplasm and connective tissues (collagen), respectively. In addition, quantitative analysis shows that we are able to detect MAF from greater imaging depths than with the near-IR RC signal. Furthermore, by performing RC imaging at 488, 543, and 633 nm, we find that a longer wavelength leads to better image contrast for deeper imaging of the bovine cornea and porcine skin tissue. Finally, by varying power of the 780-nm source, we find that comparable RC image quality was achieved in the 2.7 to 10.7-mW range.
authors.affiliation: National Taiwan University, Department of Physics, No. 1 Section 4 Roosevelt Road, Taipei 10617, Taiwan.
authors.forename: Wei-Liang
authors.initials: WL
authors.lastname: Chen
authors.forename: Chen-Kuan
authors.initials: CK
authors.lastname: Chou
authors.forename: Ming-Gu
authors.initials: MG
authors.lastname: Lin
authors.forename: Yang-Fang
authors.initials: YF
authors.lastname: Chen
authors.forename: Shiou-Hwa
authors.initials: SH
authors.lastname: Jee
authors.forename: Hsin-Yuan
authors.initials: HY
authors.lastname: Tan
authors.forename: Tsung-Hua
authors.initials: TH
authors.lastname: Tsai
authors.forename: Ki-Hean
authors.initials: KH
authors.lastname: Kim
authors.forename: Daekeun
authors.initials: D
authors.lastname: Kim
authors.forename: Peter T C
authors.initials: PT
authors.lastname: So
authors.forename: Sung-Jan
authors.initials: SJ
authors.lastname: Lin
authors.forename: Chen-Yuan
authors.initials: CY
authors.lastname: Dong
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D018613:Microscopy, Confocal / Q000295:instrumentation*; D036641:Microscopy, Fluorescence, Multiphoton / Q000295:instrumentation*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique / Q000295:instrumentation*