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
- Dr. Harvey Lui, Director, Photomedicine Institute
- Dr. Haishan Zeng
- Dr. David McLean
- Dr. Tim Lee
- Dr. Sunil Kalia
- Dr. Vincent Richer
Vancouver General Hospital Research Pavilion, The Skin Care Centre, BC Cancer Research Centre
- Dr. Qingbo Li, Beihang University
- Dr. Michael Chen, Department of Physics, Simon Fraser University
- Dr. Lioudmila Tchvialeva
- Dr. Jianhua Zhao
- Dr. Wenbo Wang
- Dr. Yimei Huang
Major Investigative Technologies Utilized
- Diffuse reflectance spectroscopy
- Multispectral imaging
- Fluorescence spectroscopy
- Fluorescence imaging
- In vivo Raman Spectroscopy
- In vivo reflectance confocal microscopy
- In vivo multiphoton microscopy
- Pulsed lasers
- Speckle analysis
- Computer image analysis
- Zhao J, Lui H, Kalia S, Zeng H: Real-time Raman spectroscopy for automatic in vivo skin cancer detection: an independent validation. Analytical and Bioanalytical Chemistry, 2015 (Online First, DOI: 10.1007/s00216-015-8914-9)
- Chen G, Liu Y, Zhu X, Huang Z, Cai J, Chen R, Xiong S, Zeng H: Phase and Texture Characterizations of Scar Collagen Second-Harmonic Generation Images Varied with Scar Duration. Microscopy and Microanalysis, 21(4): 855-862, 2015
- Wang W, Zhao J, Short M, Zeng H: Real-time in vivo Cancer Diagnosis using Raman Spectroscopy. Journal of Biophotonics, 8(7): 527-545, 2015
- Wang W, Wu Z, Zeng H: Image Distortion and its Correction in Linear Galvanometric Mirrors Based Laser Scanning Microscopy. Journal of Biomedical Optics, 20(5): 056001(1-4), 2015.
- Majdzadeh A, Lee AMD, Wang H, Lui H, McLean DI, Crawford RI, Zloty D, Zeng H: Real time visualization of melanin granules in normal human skin using combined multiphoton and reflectance confocal microscopy. Photodermatology, Photoimmunology & Photomedicine, 31:141-148, 2015.
- Liu Y, Xhu X, Hu H, Huang Z, Cai J, Chen R, Xiong S, Chen G, Zeng H: Texture analysis of collagen second harmonic generation images based on local difference local binary pattern and wavelets differentiates human skin abnormal scars from normal scars. Journal of Biomedical Optics, 20(1): 016021(1-7), 2015.
- Chen G, Lui H, Zeng H: Image segmentation for integrated multiphoton microscopy and reflectance confocal microscopy imaging of human skin in vivo. Quantitative Imaging in Medicine and Surgery, 5(1):17-22, 2015.
- Fawzy Y, Zeng H: Spectral Imaging Technology – A Review on Skin and Endoscopy Applications. Recent Patents on Medical Imaging, 4(2):101-109, 2014.