Photocoagulation Means And Method For Depilation

Abstract

Depilation is effected by use of light energy of a selected frequency band concentrated into a flexible fiber small enough to enter the region of the follicle. This effects photocoagulation tissue in a limited region determined by the placement of the fiber.

Parent Case Text

This application is a continuation-in-part of the copending abandoned application Ser. No. 23,921 filed Mar. 30, 1970.

Description

This invention relates to depilation by photocoagulation means and methods and in particular to the use of light energy to destroy hair.

BACKGROUND OF THE INVENTION

It is desirable to introduce means and methods for removing unwanted body hair painlessly. In the conventional state of the art, processes where electrolysis by either galvanic current electrochemical or high frequency diathermy techniques are employed, thermal coagulation of the tissues at the hair root takes place. These techniques, however, are not painless and are difficult to administer and gauge. Thus, expert operators must be available to determine dosage and conditions for use of these methods.

Light has been used, historically in the treatment of a number of medical problems, but until the advent of the laser, its use as a coagulator of local tissues was not widespread.

Zeiss of Germany has manufactured a Xenon arc lamp device to coagulate retinal tissue in the case of detached retina, but this was a very large, cumbersome, inefficient and costly device.

The ruby laser provided to be acceptable for the purpose of welding detached retinas, and other uses for laser coagulation have been suggested, including the epilation of hair by destruction of vascular papilla which feeds the germinal hair cells at the base of the follicle.

Unfortunately, first attempts at photoepilation were carried out with the ruby laser whose red light, and the neodymium laser, whose infrared light is ill suited for coagulation of red hemoglobin pigment in the vascular bed. In order to have effective absorption, enormous energy must be delivered because of the mismatch, and this degree of energy was sufficient to destroy the glass fiber probes.

Literature sources provide some indices to be used in determining threshold levels of coagulation of human and animal tissues using light energy. This data is available, primarily for the vascular and pigmented connective tissues of the retina. As Table 1 below indicates (1) F. A L'Esperance Jr. and G.R. Kelly, "The Threshold of the Retina to Damage by Argon Laser Radiation" Arch. Ophthal. Vol. 81, April 1969, 588 reported the determination of threshold levels of photocoagulation in the rabbit and monkey retina, using argon gas lasers whose output energy was contained in several lines between 4,579 angstroms and 5,145 angstroms in the blue-green portion of the spectrum. For comparitive purposes it should be noted that a Xenon flash lamp used in this invention was a black body radiator with peak energy at about 4,000 angstroms and much of its energy below 5500 angstroms. Thus, the comparison between these sources, in regard to biological effects, is quite reasonable.

The general levels for threshold effect, as determined by visual sign of tissue coagulation, proved to be on the order of 2 to 6 joules per square centimeter. L'Esperance reported that in an earlier study done with Xenon light by W.J. Gerraets, W.T. Ham, R.C. Williams Jr., H.A. Mueller, J. Burkhart, D. Guerry, and J.J. Vos, "Laser vs light coagular; A Funduscopic and Histological Study of Chonoretinal Injury as a function of exposure time." Fed. Proceedings Vol. 24, No. 1, Part III, Jan.-Feb. 1965, the threshold level was determined to be 4 joules per square centimeter as compared with his values of 2 to 6 joules per square centimeter for green laser light. The pulse lengths of the Gerraets study with Xenon arc lamps were varied from 175 microseconds to 30 milliseconds. A summary of the data of both studies is given in Table 1 below along with comparative data on the measured performance of a model built in accordance with the present invention.

TABLE 1

sou- energy power power rce tissue spot exposure energy J/cm.sup.2 m w/cm.sup.2 size Mj dens. watts dens. __________________________________________________________________________ ( 1) rabbit 115 4 m sec 0.26 mj 2.5 65 625 micron (1) monkey 105 2 m sec 0.12 mj 1.4 61 700 micron (1) monkey 105 4 m sec 0.24 mj 2.7 59 675 micron (1) monkey 105 10 m sec 0.57 mj 6.6 57 660 micron (2) rabbit 30 m sec 4.0 retina pre- sent follicle 100 3 m sec 0.67 mj 9.6 225 3210 re- micron sults __________________________________________________________________________

In a report following a careful measurement program of blood and tissue absorption, the present inventors determined that maximum efficiency for coupling to hemoglobin with minimum absorption in surrounding tissue could be accomplished by utilizing blue-green light of from 530-560 nanometer wave length. They, therefore suggested a "doubled neodymium" laser with spectrum output at 530 nm.

It is accordingly an object of the present invention to provide painless, simple to administer means and method of photocoagulation of tissue useful in depilation, and the like.

The invention, together with other objectives, features and advantages is described hereinafter with reference to the embodiments set forth in the accompanying drawings.

DRAWINGS

FIG. 1 is a schematic view, partially in block diagram of a Xenon arc photoepilator, showing in section view the probe as inserted into a follicle;

FIG. 2 is a view in perspective, partly diagrammatic of a linear flash lamp device as used in accordance with the invention, and

FIG. 3 is an enlarged fragmentary view in elevation and in section of the needle inserted into the hair follicle.

Therefore, in accordance with one embodiment (see FIG. 1), photocoagulation is accomplished by transmitting pulsed light energy from an arc source to terminate in the region of a hair root follicle with just enough energy in a very short pulse to destroy the life processes in the hair. In accordance with some other aspects of the invention, specific absorption of green light energy by hemoglobin may be effected to photocoagulate the blood vessel structure nourishing the hair root without significant absorption in other non-pigmented tissues at or near the hair follicle.

High energy light bursts may be obtained from gas discharge lamps 5 such as Mercury, Xenon, Argon, etc. Flash durations may be controlled by conventional pulsed power supplies 6, initiated at any desired instant by means of a switch 7, for example. Various spectral qualities can be obtained from available gas discharge lamps by employing different gases, pressures, optical filters, etc.

Typically, lamp 5 is a high peak power pulsed Xenon arc source producing peak powers in excess of 30 kilowatts when an operator closes switch 7, which might be a foot pedal trigger. The lamp produces a flash of intense visible radiation in less than a few milliseconds. Because this duration is less than the "Chronaxie" for pain fibers, there is no sensation created by the energy in the body.

The flash pulse may be obtained from a bank of storage capacitors which delivers up to 660 joules in less than a three millisecond period. These capacitors are recharged within one second, and ready to deliver the next pulse.

A spherical mirror or lens 8 of high optical speed (f/0.5) collimates the light in rays 9. The collimated light is focused by a lens system 10 as shown by rays 11 to be concentrated at the end of a flexible conduit 12 which, for example, is a single glass fiber 100 microns in diameter. A flexible steel sheath 14 or other surgical tubing may encompass the light conduit 12 to confine light and protect the fiber 12. Preferably, the steel sheath 14 is covered with polyvinyl chloride.

The ends of the fiber are carefully ground and polished to permit the maximum light energy to escape. Overall the probes may be about 48 to 60 inches long with transmission losses that should approximate no greater than about 60 percent.

At the terminal or distal tip end 15 of fiber 12, where the light energy escapes, is a stainless steel hollow needle or stainless steel tubing 17 of typically 125 to 200 microns in diameter and about 2 mm. to 4 mm. in length held in a holder 16 similar to a hypodermic syringe. This structure serves to introduce the fiber near the root 18 of hair 19 under the skin surface 20. The needle 17 serves the function of preventing escape of light energy at any other point than the terminal end 15 of fiber 12 to thereby concentrate all the energy at a known position in the vicinity of hair follicle 21 to thereby depilate the hair without damage to other surrounding tissue. The drawing shows various features out of size proportion in order to show the details and the particular mode of depilation provided by this invention.

In order to further selectively protect the adjoining tissue about the hair root 18, the light energy from arc lamp 5 may be further selected or confined to a particular waveband such as that provided by a double neodymium selective output laser, by introduction of selective filter 22. Thus, for example, light energy entering fiber 12 may be confined to green light of approximately 530 millimicron wavelength. This wavelength provides for specific absorption of the bulk of the photo energy by hemoglobin, resulting in photocoagulation of the blood vessel structure 23 in the vicinity of follicle 21 that nourishes the hair root with minimal absorption in other non-pigmented tissues at or near the hair follicle. Ultraviolet energy at about 280 millimicrons wavelength could also be used for maximum absorption in the protein materials at the hair root 18.

It has been found that the amount of photo energy to be supplied by the arc lamp source for effective use in hair depilation without sensing pain or incurring significant damage to surrounding tissue is of the order of 20 to 100 joules per square centimeter at the proximal end of a 100 micron diameter fiber which would give about 5 to 30 joules per square centimeter at the distal end of the fiber. Several successive flashes one second apart may be administered. This energy is a function of the light intensity and pulse duration, both of which may be varied to provide the optimum energy output at the follicle, but the time duration is preferably less than 3 milliseconds.

In laboratory experiments with humans, in photoepilation, it has been shown that 68 percent of the hairs release well under such conditions, with hair roots often showing a "matchstick" effect of burnt or shrivelled appearance. Biopsies showed no more than slight irritation in any case after such epilation and there were no reports of pain at the flash or afterwards. The surrounding tissue was not damaged.

Accordingly, the photocoagulation means and method afforded by this embodiment results in a simple practical improvement over prior art depilation techniques.

Another embodiment comprises a linear flash lamp having an arc length greater than 10 millimeters, preferably in the order of 40 millimeters. It provides for direct takeoff by a fiber optic cable located close to the exterior of the lamp, the takeoff being from approximately the center of the arc. Energy control may be obtained by regulating the distance of the cable end from the arc.

This embodiment does not require an extensive optical system as described in the first embodiment and thus it has been found that this type of lamp has a relatively long lifetime and gives a higher energy output at a not much greater energy input.

This embodiment (see FIG. 2) comprises a linear flash lamp 110 having two electrodes 111 and 112 located a substantial distance apart in an envelope 113. The electrodes 111 and 112 should be at least 10 millimeters apart; for example, one such lamp on the market has an arc length of 39 millimeters. The distance should be contrasted with the short arcs heretofore used, where the arc length was in the nature of 1 millimeter. The envelope 113 is also preferably very slender, typically cylindrical, and in the nature of a capillary tube. A typical diameter for such a lamp 110 is 5 millimeters, as contrasted with the 25 millimeter diameter of typical short arc lamps -- a feature which made it impossible to get very close to the arc or to get very good control of the location.

A pulsed power supply 114 is connected to the linear flash lamp, any suitable pulsing means being used. The lamp 110 may be held in place by suitable supports 115 secured to a base 116.

In conjunction with the linear flash lamp 110, this embodiment employs an optical fiber type of cable 120, which may comprise a single glass fiber 121 typically about 100 microns in diameter contained in a flexible steel sheath 122 or other surgical tubing. The fiber 121 conducts the light energy, while the sheath 122 confines the light, protects the fiber 121, and encompasses it. Preferably the steel sheath 122 is covered with an outer layer 123 of polyvinyl chloride. The ends 124 and 125 of the fiber 121 are preferably ground carefully and polished to enable the light energy to escape properly. Overall, the cable or probe 120 may be about 4 or 5 feet long, the transmission losses for their lengths approximating no more than 50 per cent. Near the outlet end of needle 125, a handle 126 is provided for use of the operator. The input end 124 of the fiber optic cable 121 lies closely adjacent the flash lamp 110.

A constant energy input of about 300 joules is a typical amount with the linear flash lamp 110, and this contrasts with the somewhat lower 60 to 200 joules, a variable amount, used in a short-arc lamp of this type.

Optics such as lenses are not required in this device, and it is noted that the energy output is greater than 0.6 millijoules as compared with an output less than 0.1 millijoule in a short arc having an input of up to 200 joules. Thus, a much greater efficiency and energy output are obtained.

In use for photoepilation, the needle 125 is inserted individually into each hair follicle, as shown in FIG. 3, operating on the principle of selective damage to hair papilla and blood supply, so that it does not affect the surrounding cells. The device is lightweight and portable, and no realignment is required between uses. It may, for example, have a 5-foot cable and the probe may be 5 or 7 mils in diameter. The harmless (to all but the hair papilla and their blood supply) high intensity light enables longer treatment sessions, and treatment of special problem areas. The selective absorption prevents scarring, and there are no hot probes to cause discomfort, so that inflammation and swelling are minimized.

It should be noted that an advantage of the photoepilation technique over the thermolysis technique is the distance the needle must penetrate into the skin into the hair follicle in order to destroy it. Using the photoepilation technique the needle need only penetrate the skin into the follicle a small distance, approximately one-sixteenth inch, whereas the use of the thermolysis technique requires the placement of the needle down near the root of the follicle in order to properly treat the hair. Therefore, the light transmitting means in photoepilation need only be inserted a small distance into the follicle to destroy the hair. Thus there is less chance of accidentally damaging the surrounding tissue along with a further reduction in pain utilizing the photoepilation technique.

In a modified form of this embodiment, the appearance is exactly the same except at the output end, where in place of a needle there is merely a blunt end. In this instance, the fiber optics cable is somewhat larger, -- for example, about one-eighth inch in diameter -- and contains several thousand individual small-diameter fibers. Otherwise the structure is unchanged. As a result, over 20 millijoules of energy can be delivered from the distal end of the cable. This has proven sufficient for performing retinal coagulation, the cable end being mounted in a standard hand ophthalmoscope and delivered from there through the optical system of the ophthalmoscope. Thus, a short-pulse, long-arc xenon lamp retinal photocoagulator is provided that operates in the green region of the spectrum and is capable of coagulating retinal blood vessels.

Claims

What is claimed is:

1. The method of epilation, comprising in combination the steps of

a. Producing a pulse of high energy light by electronically triggering a gaseous media to produce visible light radiation,

b. Positioning a flexible thin single fiber conduit formed from fiberoptic material capable of transmitting said light energy from the gaseous media so that the input end of said conduit collects intense light from said high energy light and the output end of said conduit is positioned in a hair follicle, and

c. Transmitting said pulse of light energy in said conduit with enough energy passed through said conduit to said hair follicle to cause photocoagulation of body tissue in the vicinity of said region at an intensity killing the hair.

2. The method defined in claim 1, including the additional step of limiting the frequency of the light energy to a predetermined bandwidth.

3. The method defined in claim 2, including the additional step of producing light of a wavelength in the green region of the light spectrum that is specifically absorbed by hemoglobin, thereby selectively photocoagulating the blood vessel structure about the region with the light energy becoming significantly absorbed in other nonpigmented tissues near the region.

4. The method defined in claim 2, including the additional step of limiting the light energy supplied to the follicle to less than 3 millijoules.

5. The method defined in claim 1 including the step of limiting the light pulse to less than 3 milliseconds in duration.

6. The method as defined in claim 1 including the step of successively flashing said light energy a plurality of times at approximately 1 second intervals.

7. The method defined in claim 1, including locating the output end of said conduit only partly within said hair follicle.

8. Depilation apparatus for depilation by photocoagulation in a limited region about a hair root comprising in combination,

a. A high energy gaseous medium light source including electrical means for producing therein short intense pulses of light,

b. A single fiber conduit formed from fiberoptic material positioned to transmit light energy from said source to said region with a polished end for inserting into the follicle for releasing the transmitted light energy in said body tissue, and

c. Means for locating said polished output end of said conduit in the follicle.

9. Apparatus as claimed in claim 8, wherein said locating means comprises a needle having a cavity therein for receiving a portion of said conduit at the terminating end.

10. Apparatus as defined in claim 8 wherein said light energy producing means further comprises a spherical lens of high optical speed which collimates said light in rays.

11. Apparatus as defined in claim 10, including a lens system for focusing said collimated light to be concentrated at the end of said flexible conduit.

12. Apparatus as defined in claim 8, further comprising means for producing light energy from said pulse to provide light in a specific range of the spectrum.

13. Apparatus as defined in claim 12, wherein said light as provided in the green range of the spectrum.

14. Apparatus as claimed in claim 12, wherein said light is provided having a wave length of approximately 530 nanometers.

15. Apparatus as claimed in claim 8, in which means provides light energy at the end of said conduit to reach said region with approximately one-half to 3 millijoules.

16. Apparatus as claimed in claim 8 limited to produce light flashes of less than 3 milliseconds in duration.

17. Apparatus as claimed in claim 16 adapted to produce a series of successive flashes at approximately 1 second intervals.

18. Photoepilation, comprising

producing pulses primarily of blue-green high-energy light in a gaseous medium across an arc longer than the millimeters,

transmitting said light through a single fiber optic filament of about 5 to 7 mills thickness directly from an input end adjacent said arc to a needle end,

inserting said needle end into a hair follicle, and transmitting into said follicle the pulses for a time sufficient to coagulate the tissue therein responsible for hair growth.

19. Photoepilation according to claim 18 wherein the energy input is approximately 300 joules and the output is greater than 0.6 millijoules.

20. Photoepilation according to claim 18, wherein in said inserting step said needle is inserted only partly into said hair follicle.