title: Deep optical imaging of tissue using the second and third near-infrared spectral windows.
abstract: Light at wavelengths in the near-infrared (NIR) region allows for deep penetration and minimal absorption through high scattering tissue media. NIR light has been conventionally used through the first NIR optical tissue window with wavelengths from 650 to 950 nm. Longer NIR wavelengths had been overlooked due to major water absorption peaks and a lack of NIR-CCD detectors. The second NIR spectral window from 1100 to 1350 nm and a new spectral window from 1600 to 1870 nm, known as the third NIR optical window, were investigated. Optical attenuation measurements from thin tissue slices of normal and malignant breast and prostate tissues, pig brain, and chicken tissue were obtained in the spectral range from 400 to 2500 nm. Optical images of chicken tissue overlying three black wires were also obtained using the second and third spectral windows. Due to a reduction in scattering and minimal absorption, longer attenuation lengths and clearer optical images could be seen in the second and third NIR optical windows compared to the conventional first NIR optical window. A possible fourth optical window centered at 2200 nm was noted.
authors.affiliation: City College of the City University of New York, Institute for Ultrafast Spectroscopy and Lasers, and Department of Physics, 160 Convent Avenue, New York 10031.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Sordillo
authors.affiliation: City College of the City University of New York, Institute for Ultrafast Spectroscopy and Lasers, and Department of Physics, 160 Convent Avenue, New York 10031.
authors.forename: Yang
authors.initials: Y
authors.lastname: Pu
authors.affiliation: City College of the City University of New York, Institute for Ultrafast Spectroscopy and Lasers, and Department of Physics, 160 Convent Avenue, New York 10031bUniversidade de São Paulo, Instituto de Física de São Carlos, São Carlos 05508-060, Brasil.
authors.forename: Sebastião
authors.initials: S
authors.lastname: Pratavieira
authors.affiliation: City College of the City University of New York, Institute for Ultrafast Spectroscopy and Lasers, and Department of Physics, 160 Convent Avenue, New York 10031.
authors.forename: Yury
authors.initials: Y
authors.lastname: Budansky
authors.affiliation: City College of the City University of New York, Institute for Ultrafast Spectroscopy and Lasers, and Department of Physics, 160 Convent Avenue, New York 10031.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Alfano
mesh_terms: D000818:Animals; D001923:Brain Chemistry / Q000502:physiology; D001943:Breast Neoplasms / Q000737:chemistry / Q000473:pathology; D002645:Chickens; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061848:Optical Imaging / Q000379:methods*; D011471:Prostatic Neoplasms / Q000737:chemistry / Q000473:pathology; D012815:Signal Processing, Computer-Assisted; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013552:Swine