The Photomedicine Institute is dedicated to harnessing the energy of light to obtain diagnostic information about the skin as well to treat the skin. From an optical point of view, the skin is an inhomogeneous, multi-layered, turbid medium. When light interacts with tissue, it is scattered and absorbed, and the tissue may produce fluorescence. These interactions and the optical properties of tissue determine the distribution of incoming light on the tissue, which is critical for generating biological effects and therapeutic applications. On the other hand, the optical properties and the effects of tissue on light are determined by the chemical composition, morphological structure, and physiological state of the tissue. Therefore, pathological changes in tissue affect the re-emitted optical signals detected when a beam of light is used to illuminate the skin.

Light based measurements of skin have the potential to improve non-invasive clinical diagnosis of various skin conditions including skin cancer. It may also lead to non-invasive assessment of treatment progress. We are currently exploring a couple of different types of optical measurement modalities for skin diagnosis:

• Diffuse Reflectance Spectroscopy and Multi-spectral Imaging, which explores elastic light scattering and light absorption by skin chromophores such as melanin, hemoglobin, bilirubin, and water.
• Fluorescence Spectroscopy and Imaging, which explore molecular electronic energy transition-related light emission of certain cutaneous molecules such as tyrosine, tryptophan, NADH, collagen, and elastin.
• Raman Spectroscopy, which explores inelastic light scattering to give fingerprint-like spectral signatures of molecular vibrations. Molecules in skin that have unique Raman signatures include proteins, DNA, lipids, glucose, and melanin.
• In-Vivo Confocal Microscopy, which provides sectional images of the skin at micron spatial resolution, allowing us to visualize cellular structures and micro-circulation in real time on living skin. Imaging mechanisms we are exploring include elastic scattering (reflectance), two-photon excitation fluorescence (TPEF), and second harmonic generation (SHG).
• Laser Speckle Imaging, which analyzes interference patterns from light reflected off skin surfaces.
• Nanophotonics involves the application of nanotechnologies to enhance light-tissue interactions for diagnostic and therapeutic applications: e.g. using metal nanoparticle based SERS (surface enhanced Raman scattering) spectroscopy for diagnostics and developing nanoparticle based photothermal therapy.

Light of different wavelengths, intensities, and pulse widths can be harnessed to treat various skin conditions such as skin cancer, psoriasis, and port wine stains. We are currently working on the following four types of phototherapies:

• Ultraviolet Phototherapy
• Laser Surgery
• Photodynamic Therapy
• Two-Photon Excitation

principal investigators

Dr. Harvey Lui, Director, Photomedicine Institute Dr. Haishan Zeng Dr. David McLean Dr. Tim Lee Dr. Sunil Kalia

Lab Location

Vancouver General Hospital Research Pavilion, The Skin Care Centre, BC Cancer Research Centre

VISITING SCIENTISTs

Dr. Jianxin Chen, Fujian Normal University, China Dr. Naiyan Huang, PLA General Hospital, Beijing, China

collaborator

Dr. Michael Chen, Department of Physics, Simon Fraser University

research associates

Dr. Lioudmila Tchvialeva Dr. Jianhua Zhao

CLINICAL RESEARCH FELLOW

Soodabeh Zandi

Post-Doctoral FelloWs

Dr. Anthony Lee

Graduate Students

Ms. Tracy Wang Mr. Paul Wighton Mr. Edward Yu Mr. Shuang Wang (Visiting)

Staff

Mr. Wei Zhang

Major Investigative Technologies Utilized

Diffuse reflectance spectroscopy, fluorescence spectroscopy, fluorescence imaging, Raman spectroscopy, in vivo confocal microscopy, pulsed lasers, speckle analysis, computer image analysis

Recent Publications

Zhao J, Lui H, McLean DI, Zeng H. Integrated real-time Raman system for clinical in vivo skin analysis. Skin Res Technol 2008 (in press). Zhao J, Lui H, McLean DI, Zeng H. Automated autofluorescence background subtraction algorithm for biomedical Raman spectroscopy. Appl Spectroscopy 2007; 61:1225-32. Zhao J, Lui H, McLean DI, Zeng H. Towards instrument independent quantitative measurement of fluorescence intensity in fiber optic spectrometer systems. Appl Optics 2007; 46:7132-40. Chen R, Huang Z, Lui H, Hamzavi I, McLean DI, Xie S Zeng H. Monte Carlo simulation of cutaneous reflectance and fluorescence measurements—the effect of melanin contents and localization, Journal Photochem Photobiol B: Biol 2007; 86:219-226. » more publications...

09.28.11