Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
  • A61B18/18—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves
  • A61B18/20—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser
  • A61B18/203—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser applying laser energy to the outside of the body
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
  • A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
  • A61B2018/00452—Skin
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
  • A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
  • A61B2018/00452—Skin
  • A61B2018/00476—Hair follicles

Definitions

• the invention relates generally to a method of permanent hair removal using laser light. More specifically, the invention relates to the transcutaneous use of laser light to target the keratin component of hair, thus destroying the hair by photothermo lysis without damage to surrounding skin or tissue.
• Intrafollicular methods comprise the delivery of laser light thru a small probe tip to the hair follicle.
• the light utilized is of a wavelength which is readily absorbed by either the melanin in the hair or the hemoglobin in the blood vessels surrounding the papilla. This absorption of light energy produces heat, resulting in damage to the hair shaft, photocoagulation of the tissue surrounding the papilla, and subsequent destruction of the hair. Because the light energy employed in this method is absorbed by either blood or melanin in the skin, it requires the use of a very narrow beam of light to target a single hair at a time and prevent damage to the surrounding tissue.
• Transcutaneous laser hair removal methods utilizes a substance which is massaged into the skin to penetrate the hair ducts. After cleaning the substance from, the skin's surface, light of a wavelength which passes through the skin, but which is absorbed by the substance, is directed onto the treated area. The absorption of energy by the substance applied to the hair duct causes photocoagulation of the tissue surrounding the papilla and results in destruction of the hair.
• this method allows for treatment of a sizable area of skin, it requires the inconvenient, time consuming application of the light-absorbing substance. In addition, great care must be taken to completely remove the substance from the skin's surface prior to the laser treatment to avoid damage to the skin.
• the invention relates to a method of permanent hair removal used primarily for cosmetic purposes.
• This method comprises the transcutaneous use of laser light having wavelength in the 880-930 nanometer range wherein the light is directed onto an area of skin on which hair removal is desired.
• Light of this wavelength passes through the skin with only minimal absorption by blood, blood components, and melanin.
• This wavelength is, however, readily absorbed by the protein keratin, the main component of hair of all colors. Absorption of the light energy by the keratin produces heat, which damages the hair shaft and root and photocoagulates the blood vessels and tissue surrounding the papilla, resulting in destruction of the hair and preventing its re-growth.
• the method also includes the use of a second wavelength of laser light produced by known means, such as second harmonic generation or 3 -mixing plus second harmonic generation, from the same laser source which generates the primary 880-930nm wavelength.
• This second wavelength of light which will be in the 440-465 nanometer range, is readily absorbed by both blood components and melanin.
• An intrafollicular probe is used to deliver the second wavelength of light to the hair follicle, in the manner described in the prior art, to treat the small percentage of hairs having papillas at a skin depth beyond the effective range of the primary wavelength of light. In this fashion, a single laser light source can be used to treat all types of hair in the least painful and most efficient, cost effective, and convenient manner possible.
• Figure 1 is a sectional view of an area of skin showing the structure of hair and skin and the transcutaneous application of laser light.
• Figure 2 is a graph showing the abso ⁇ tion spectrum of hemoglobin, melanin, and keratin in the visible and near infra-red light range.
• Figure 3 is a sectional view of an area of skin showing the structure of hair and skin and the intrafollicular application of laser light.
• Figure 1 illustrates the preferred embodiment of the invention.
• laser light 18 emanates from the probe tip 19 of a fiber optic cable, not shown, and is directed onto the surface of the skin.
• the other end of the fiber optic cable is connected to a laser light source, also not shown.
• the size and shape of the light beam may be customized to meet the requirements of any individual application.
• Figure 1 also illustrates the structure of hairs 9 and the surrounding upper and lower skin layers, known as the epidermis 16 and the dermis 17, respectively.
• Hair 9 comprises shaft 10, shown shaved near the surface of the skin, and root 11.
• Follicle 13 is a sac which encloses shaft 10, root 11 and adjacent sebaceous glands 15.
• papilla 12 Located at the lower end of follicle 13 is the papilla 12, which is fed by blood vessels 14 and provides nourishment to root 11. In order to prevent regrowth of hair 9, it is the papilla 12 and blood vessels 14 which must be damaged sufficiently to prevent continued nourishment of root 11.
• Figure 2 illustrates the relatively high abso ⁇ tion of light in the 880-930 nm wavelength range by the protein keratin.
• Figure 2 also shows the relatively low abso ⁇ tion of light in the same range by the hemoglobin and melanin present in the tissue surrounding the hair. These abso ⁇ tion characteristics of keratin, hemoglobin, and melanin allow the transcutaneous use of light of the chosen wavelength to target the keratin in the hair shaft and subsequently destroy the papilla without damage to the surrounding tissue.
• the preferred embodiment of the invention primarily utilizes laser light 18 having wavelength in the 880-930 nanometer range. As indicated in Figure 2, light of this wavelength passes through the dermis 17 and the epidermis 16 with only minimal abso ⁇ tion by blood, blood components, and melanin. This wavelength is, however, readily absorbed by the protein keratin, which is the main component of hair of all colors. Abso ⁇ tion of the light energy by the keratin produces heat, which damages the hair shaft 10 and root 11. This heat may also photocoagulate the blood vessels 14 feeding the papilla 12, resulting in destruction of the hair 9 and increasing the probability of permanent removal.
• Power level and duration of the laser pulse directed onto the skin must be carefully chosen to optimize the conduction of heat from the hair shaft and root to the papilla.
• a 0.1 second pulse from a laser delivering a power level of approximately 6 milliwatts per hair to the root would deliver sufficient energy to the hair shaft and root to result in significant damage to the papilla and a high probability of permanent hair removal.
• Use of a shorter, higher energy laser pulse will rapidly vaporize the hair, resulting in hair removal below the surface with little probability of permanent hair destruction.
• Pulses of less than 0.0001 seconds in duration having sufficient energy to damage hair can lead to very explosive, i.e. photoacoustic, abso ⁇ tion and to hyper- or hypo-pigmentation.
• a pulse longer than 0.2 seconds can result in damage to the surrounding tissue and possible scarring.
• the preferred embodiment of the invention further comprises the intrafollicular application of laser light 18 having a second wavelength, as shown in Figure 3.
• This second wavelength is produced by known means, such as second harmonic generation or 3 -mixing plus second harmonic generation, from the same laser source which generates the primary 880-930 nm wavelength.
• the intrafollicular probe 20 is used to deliver laser light 18 of the second wavelength directly into the follicle 13 and of a hair 9 having papilla 12 at skin depth beyond the effective range of the transcutaneous method.
• This second wavelength of light in the 440-465 nanometer range, is readily absorbed by either the melanin in the hair 9 or the hemoglobin in the blood vessels 14 surrounding the papilla 12, resulting in damage to the hair shaft 10, photocoagulation of the tissue surrounding the papilla, and subsequent destruction of the hair.
• a single, inexpensive, laser light source can be used to treat all types of hair in the least painful and most efficient, cost effective, and convenient manner possible.

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• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Surgery (AREA)
• Optics & Photonics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Molecular Biology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Electromagnetism (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Medical Informatics (AREA)
• Otolaryngology (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Radiation-Therapy Devices (AREA)
• Laser Surgery Devices (AREA)

Applications Claiming Priority (1)

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• 1998
  • 1998-10-28 WO PCT/CA1998/001005 patent/WO2000024464A1/en not_active Ceased
  • 1998-10-28 EP EP98951130A patent/EP1124612A1/de not_active Withdrawn
  • 1998-10-28 AU AU97314/98A patent/AU9731498A/en not_active Abandoned
  • 1998-10-28 JP JP2000578065A patent/JP2002528191A/ja active Pending
  • 1998-10-28 CA CA002348788A patent/CA2348788A1/en not_active Abandoned

Non-Patent Citations (1)

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