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In vivo near-infrared autofluorescence imaging of pigmented skin lesions: methods, technical improvements and preliminary clinical results

Authors

  • Shuang Wang,

    1. Imaging Unit – Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, BC, Canada
    2. Laboratory for Advanced Medical Photonics, Photomedicine Institute, Department of Dermatology and Skin Science, University of British Columbia and Vancouver Coastal Health Research Institute, Vancouver, BC, Canada
    3. Institue of Photonics and Photon-Technology and Department of Physics, Northwest University, Xi'an, Shaanxi, China
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  • Jianhua Zhao,

    1. Imaging Unit – Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, BC, Canada
    2. Laboratory for Advanced Medical Photonics, Photomedicine Institute, Department of Dermatology and Skin Science, University of British Columbia and Vancouver Coastal Health Research Institute, Vancouver, BC, Canada
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  • Harvey Lui,

    1. Imaging Unit – Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, BC, Canada
    2. Laboratory for Advanced Medical Photonics, Photomedicine Institute, Department of Dermatology and Skin Science, University of British Columbia and Vancouver Coastal Health Research Institute, Vancouver, BC, Canada
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  • Qingli He,

    1. Institue of Photonics and Photon-Technology and Department of Physics, Northwest University, Xi'an, Shaanxi, China
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  • Haishan Zeng

    Corresponding author
    1. Laboratory for Advanced Medical Photonics, Photomedicine Institute, Department of Dermatology and Skin Science, University of British Columbia and Vancouver Coastal Health Research Institute, Vancouver, BC, Canada
    • Imaging Unit – Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, BC, Canada
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Address:

Dr Haishan Zeng

Imaging UnitIntegrative Oncology Department

British Columbia Cancer Agency Research Centre

675 West 10th Avenue

Vancouver, BC, V5Z 1L3

Canada

Tel: +1 604 675 8083

Fax: +1 604 675 8099

e-mail: hzeng@bccrc.ca

Abstract

Background/purposes

Fluorescence emission from in vivo cutaneous melanin was recently detected under near-infrared (NIR) excitation by our group. We then built a prototype NIR autofluorescence imaging system to observe and characterize the melanin distribution in human skin. In this article, we reported a new setup of NIR fluorescence imaging system and calibration methods to optimize the system for better clinical feasibility and clearer image.

Methods

The imaging system was designed to perform both fluorescence and reflectance imaging with a 785-nm fiber-coupled laser source. The illumination light was purified by a 785-nm bandpass filter for fluorescence excitation; while the spontaneous components were selected by a longpass filter for NIR reflectance imaging. A hand-controlled filter wheel was used to switch these two filters for different imaging modes. A dichroic filter was used to guide the illuminating light onto the skin surface for excitation. Reflectance and fluorescence signals were collected sequentially by a NIR optimized CCD camera. The captured images were calibrated by the reflectance images of a standard reflectance disk for non-uniform illuminations and light collection efficiencies.

Results

The clinical results demonstrated that NIR fluorescence intensities and distribution patterns vary among lesion types. It was also confirmed that pigmented skin lesions emitted higher NIR fluorescence than the surrounding normal skin due to the presentation of higher concentrations of cutaneous melanin within the lesions.

Conclusion

NIR autofluorescence imaging system could be utilized as a powerful tool for visualizing melanin distribution in pigmented skin lesions and as a potential method for aiding melanoma detection.

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