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Selective photothermolysis to target sebaceous glands: Theoretical estimation of parameters and preliminary results using a free electron laser

Authors

  • Fernanda H. Sakamoto MD, PhD,

    1. Wellman Center for Photomedicine, Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, 02114
    2. Harvard Medical School, Department of Dermatology, Boston, Massachusetts, 02114
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  • Apostolos G. Doukas PhD,

    1. Wellman Center for Photomedicine, Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, 02114
    2. Harvard Medical School, Department of Dermatology, Boston, Massachusetts, 02114
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  • William A. Farinelli BA,

    1. Wellman Center for Photomedicine, Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, 02114
    2. Harvard Medical School, Department of Dermatology, Boston, Massachusetts, 02114
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  • Zeina Tannous MD,

    1. Wellman Center for Photomedicine, Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, 02114
    2. Harvard Medical School, Department of Dermatology, Boston, Massachusetts, 02114
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  • Michelle Shinn PhD,

    1. Thomas Jefferson National Accelerator Facility, Newport News, Virginia, 23606
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  • Steve Benson PhD,

    1. Thomas Jefferson National Accelerator Facility, Newport News, Virginia, 23606
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  • Gwyn P. Williams PhD,

    1. Thomas Jefferson National Accelerator Facility, Newport News, Virginia, 23606
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  • Joseph F. Gubeli III MS,

    1. Thomas Jefferson National Accelerator Facility, Newport News, Virginia, 23606
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  • H. Frederick Dylla PhD,

    1. American Institute of Physics, College Park, Maryland 20740
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  • R. Rox Anderson MD

    Corresponding author
    1. Wellman Center for Photomedicine, Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, 02114
    2. Harvard Medical School, Department of Dermatology, Boston, Massachusetts, 02114
    • 55 Fruit St. BHX 630, 02114 Boston, MA.
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  • Disclosure of Proprietary Interests: None of the authors have a conflict of interest regarding this publication.

Abstract

Background and Objectives

The success of permanent laser hair removal suggests that selective photothermolysis (SP) of sebaceous glands, another part of hair follicles, may also have merit. About 30% of sebum consists of fats with copious CH2 bond content. SP was studied in vitro, using free electron laser (FEL) pulses at an infrared CH2 vibrational absorption wavelength band.

Methods

Absorption spectra of natural and artificially prepared sebum were measured from 200 to 3,000 nm, to determine wavelengths potentially able to target sebaceous glands. The Jefferson National Accelerator superconducting FEL was used to measure photothermal excitation of aqueous gels, artificial sebum, pig skin, human scalp, and forehead skin (sebaceous sites). In vitro skin samples were exposed to FEL pulses from 1,620 to 1,720 nm, spot diameter 7–9.5 mm with exposure through a cold 4°C sapphire window in contact with the skin. Exposed and control tissue samples were stained using H&E, and nitroblue tetrazolium chloride staining (NBTC) was used to detect thermal denaturation.

Results

Natural and artificial sebum both had absorption peaks near 1,210, 1,728, 1,760, 2,306 and 2,346 nm. Laser-induced heating of artificial sebum was approximately twice that of water at 1,710 and 1,720 nm, and about 1.5× higher in human sebaceous glands than in water. Thermal camera imaging showed transient focal heating near sebaceous hair follicles. Histologically, skin samples exposed to ∼1,700 nm, ∼100–125 milliseconds pulses showed evidence of selective thermal damage to sebaceous glands. Sebaceous glands were positive for NBTC staining, without evidence of selective loss in samples exposed to the laser. Epidermis was undamaged in all samples.

Conclusions

SP of sebaceous glands appears to be feasible. Potentially, optical pulses at ∼1,720 or ∼1,210 nm delivered with large beam diameter and appropriate skin cooling in approximately 0.1 seconds may provide an alternative treatment for acne. Lasers Surg. Med. 44:175–183, 2012. © 2012 Wiley Periodicals, Inc.

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