Optical spectroscopy and imaging for early lung cancer detection: a review  Haishan Zeng, Annette McWilliams, Stephen Lam, MD, FRCPC  Photodiagnosis and Photodynamic Therapy  Volume 1, Issue 2, Pages 111-122 (September 2004) DOI: 10.1016/S1572-1000(04)00042-0 Copyright © 2004 Elsevier B.V. Terms and Conditions

Figure 1 Schematic diagram of light pathways in bronchial tissue. A beam of incident light could interact with the bronchial tissue and generate various secondary photons measurable at the tissue surface: specular reflection, diffuse reflection, fluorescence, and Raman scattering. These measurable optical properties can be used for determining the structural features as well as the biochemical composition and functional changes in normal and abnormal bronchial tissues. Photodiagnosis and Photodynamic Therapy 2004 1, 111-122DOI: (10.1016/S1572-1000(04)00042-0) Copyright © 2004 Elsevier B.V. Terms and Conditions

Figure 2 Schematic illustration of Raman scattering process. When light with photon energy hν0 interact with a molecule, the molecule is first excited to a virtual state (horizontal dashed line). The molecule immediately returns to a higher energy vibrational state with the emission of an altered photon hν. Part of the energy (ΔE) from the incident photon is transferred to induce molecular vibrations, leaving the scattered photon with reduced energy, hν = hν0 − ΔE. Photodiagnosis and Photodynamic Therapy 2004 1, 111-122DOI: (10.1016/S1572-1000(04)00042-0) Copyright © 2004 Elsevier B.V. Terms and Conditions

Figure 3 White-light and autofluorescence images of a carcinoma in situ lesion in the left main bronchus. (a) White-light bronchoscopic image showing a subtle nodular lesion. (b) Autofluorescence image of the same area. The tumor area appears brownish red (arrow) against a normal green background (LIFE-Lung™ II Device, Xillix Technologies Inc., Richmond, BC, Canada). Photodiagnosis and Photodynamic Therapy 2004 1, 111-122DOI: (10.1016/S1572-1000(04)00042-0) Copyright © 2004 Elsevier B.V. Terms and Conditions

Figure 4 Example WLB images, reflectance spectral curves (a–c) and AFB images and fluorescence spectral curves (d–f) of a CIS lesion and its surrounding normal tissue. (a) WLB image with the optical fiber almost outside of the interim image field; (b) WLB image when the fiber is aligned with the CIS lesion for spectral measurement and shows as a black spot; (c) reflectance spectra obtained from the CIS and its surrounding normal tissue. (d) AFB image with the fiber almost outside of the interim image field; (e) AFB image when the fiber is aligned with the CIS lesion for spectral measurement; (f) fluorescence spectra from the CIS and its surrounding normal tissue (OmniScope™ Device, SpectraVu Medical Inc., Vancouver, BC, Canada; from ref. [34] with permission). Photodiagnosis and Photodynamic Therapy 2004 1, 111-122DOI: (10.1016/S1572-1000(04)00042-0) Copyright © 2004 Elsevier B.V. Terms and Conditions

Figure 5 The mean Raman spectra of normal bronchial tissue (n = 12), adenocarcinoma (n = 6) and squamous cell carcinoma (n =1 0). Each spectrum was normalized to the integrated area under the curve to correct for variations in absolute spectral intensity. Each spectral peak can be assigned to specific biomolecules inside the tissue such as nucleic acids and proteins. The Raman signatures for tumour are significantly different from normal tissue (with permission from ref. [83]). Photodiagnosis and Photodynamic Therapy 2004 1, 111-122DOI: (10.1016/S1572-1000(04)00042-0) Copyright © 2004 Elsevier B.V. Terms and Conditions