CA2224356A1

CA2224356A1 - Skin treatment process using laser

Info

Publication number: CA2224356A1
Application number: CA002224356A
Authority: CA
Inventors: Nikolai I. Tankovich; Lawrence H. Sverdrup, Jr.; Richard G. Episcopo
Original assignee: Individual
Current assignee: Thermolase Corp
Priority date: 1995-06-12
Filing date: 1996-06-12
Publication date: 1996-12-27
Also published as: US5817089A; US6036684A; AU6275796A; WO1996041579A1

Abstract

This invention is a skin treatment process for the removal of superficial epidermal skin cells (12); the reduction or removal of unwanted hair (28); and the mitigation of skin conditions such as acne and seborrhea. A contaminant (4) having a high absorption at a wavelength of light is topically applied to a skin section. A preferred contaminant is a mixture of 20 % of one micron graphite particles in mineral oil. Portions of the contaminant are forced into spaces between the superficial epidermal skin cells, into hair ducts in the skin, and/or into adjacent sebaceous glands. The skin section is illuminated with laser pulses at the matching wavelength, so as to impart sufficient energy to the contaminant to cause explosion of the particles in the contaminant. The energy released by the explosions blows off layers of dead skin cells, and/or destroys tissue responsible for hair growth, and/or sebum production.

Description

W O 96/41579 PCTnJS96/10155 SKIN TrF~.T M ~T PROCESS USING l~ ~'' This invention is a ~ n in part of Serial No. 08/280928 filed 7/26/94, Serial No. 08/257,021 s~hPAlllPA~ to issue as Patent No. 5,423,803 on 6/13/95, and Serial No. 08/005,810 i;led 1/19/93, seh~ l1OA to issue Patent S No. 5,425,728 on 6/20/95 which was a CQ~ tirm in part of Serial No.
07/783.789 filed 10/29/91, now Patent No. 5,226,907 issued July 13, 1993.
This invention relates~ to procp-~cps for skin tre~tm~-n~ and in particular to such procçcces which will utilize lasers.

BACKGROUND OF THE INVENTlON
The Skin A sechon of human skin showing a cross secti~m of one hair is shown in FIG. 1. ~;IG. 1 shows the hair shaft 33 of a hair ~,wl.~g in a hair duct 31, from (1~nnsll papilla 32, a ner~e ending 34, a s veat gland 35 a se~~eollC gland 38, arteAes 36 and veins 37.
T_ree major CO~r4~.. C relating to human skin are (1) ~c~lmnls~tinn of excess layers of dead skin cells on m iddle age and elderly people which cause them to appear older, (2) skin çon~ nc such as acne and seborrhea and (3) ullw~ed hair.
Dead Layers of Skin The ep;de-rmic~ 39 in FIG. 1, of the hnm~n skin co~llses several ~lictinct layers of skin tissue. These layers of tissue are depicted in block diagram form in FIG. 2. The ~leepest layer is the ~L.d~ basale layer which cl~ of c~h....~-~r cells. The next layer up is the sli~ .., spinosnm y~osedofpolyhedralcells. Cellspnchedupfromthe :~hd~ s~ os ...are 25 fl~tten~-d and synthe-ci7e keratohyalin granules to form the :,Ll~lUIu grz~mlll~s~lm layer. As these cells move ~uLw~d they lose their nuclei and the keratohyalin granules fuse and mingle with tonofibrils. This forms a clear layer called the u h~ lllm The cells of the Sllalull~ nm are closely p~ e-l As the cells move up from the ~llalulll hlri~l~lm they become co~ lc~ed into many W O 96/41579 PCT~US96/10155 layers of opA~llle S~ ..Ac. These fl~ttçnetl cells have I~CO11lG co~!~ t~ly filled with keratin and have lost all other int~rn~l structure, in~lu~lin~ nuclei. These c c~ ç the outer layer of the epidermi~, the sL~d~ ç~Tn~llm At the lw~lu of the sL~ corn~ m the cells are closely r~mr~cted and adhere S to one Anr~th~r ~LIull~ly, but higher in the ~ LLulll they bec~n~ loosely packed and ev~lllually flake away at the sllrf~ce. For example, in the cheek skin of a 50 year old face the outer layer of the SL~ co~n~ m typically CQ ~ of about 15 layers, and the layers flake away at the rate of about one or two layers per month. So we naturally get a completçly new sl,~Lulll c~rnellm on 10 our faces about twice per year.
It is well known that the le~uv~l of a few snrf~ ~e layers of a person's skin will generally result in yuull~er loohng skin. Many ter~ni~ s have been tried to produce this effect. A mild SU~IJU1n will cause slight blicte~ing of the skin after which an OlltCi~l~' layer of the skin peels off. This 15 generally leaves a ~uull~ r looking skin sllrf~e Similar results can be obtained by abrasion procçcc~s SUC]l as actually S~ lg away the 5mrf~c~ layer with an abrasive m~teri~l such as fine sand paper.
Recent a~LGI-1~b have been made to utiLzG laser beams to "cook" the sllrf~r~ layer of skin. This coohn~ causes the skin to blister after which the 20 s~lrf~ce layers can be scraped away. Also, people have been ~ nting with lasers which ~;'1"" ;~r, the olltcitle sllrf~r~, These prior art procçCces present some b~on~firi~l results but also provide l,ole~Lial risk to the p~tiPntThe slight ~ Lu~ res_.lb a risk of unde1ly-- ~; long term ~l~ma~e to the ski~L
Abrasion p~ ec often result in '~ leedin~ and pain and som~otim~C infection, 25 scabbing, and slight scarring. Laser ~ . can result in pain and nnflf-cired b ~. ..ill~, and if not applied ~ can result in hlee-ling and ScA ~
Acne and Seborrhea Skin con~liti~nc such as aene and s~o1-Lc;a are believed to be 30 caused or exace,l,aled by ~ssi.,~ sebum flow pro~hlre~l by seb~reonc glands most of which are ~ljrqrPnt to and discharge sebum into, hair fcllirlPs. Sebum is co ~pose~l of keratin, fat, and c~-lh~lq- debris. Sebum form~s a moist, oily,acidic ilm that is mildly qntihqct~Priql and ~..,;r....~l and may to some extentprotect the skin agqinct drying. The fimrhnrl of the sebum excretion in man is 5 c~nlro._ ~ial and it may very well serve no useful filnrti~n whatsoever. It isknown that the b-qcte~i-q- which cause acne is propinnih~ ... acne or (P-acnes). T_is b~-te-ris grows in sebum. ~ nifirqnt sebum flow in l.. ~-.c begins at p.~ . This is when acne ~o~'~c arise. Males c~l~lcd before puberty do not develop acne or ~eb~..l.~o--q Seborrhea is any of several commnn skin cQn~3ihnnc in which there is an u.~ ction of sebum resnltin~ in ~,~cessi~e oilinf.~c or dry scales.
Sel~--l,ea inrln~les seborrheic fl.o....~lil;c (cradle cap, dandru~), ~I,o~ ea CQ-~Sl;vca, seborrh~;c bleph~hili~, and sebnrrhoir kelatosis Unwanted Hair Remo~q~ o~ !ed hair i~ a larg~ h~llcjn~5c tn the Un1ted ~tqte Terhni1lles inr~ 3e short term removal techni-lues such as shaving and phll~lrin~ and long term (sometimes permqn-ont) removal techni1lles such as electrolysis. Attempts have been made to use laser beams for hair rGlll~V;ll.
Prior art m~tho~i~ for perm-q-n~nt or long term hair re .,v~l are generally 20 painful and very time ~
Graphite Particles It is known that graphite vapol~s at about 3,600DC. It is known that graphite is a strong absorber of i~aled light and that i~ed light such as the 1.06 micron laser beam pro~ ce-l by the Nd:YAG laser will penetrate 25 several millim.oterc through human skin.
What is Nee ~- d ~ What is nPe~le~ is a simple quick tre-~tm~-nt process which could be used to treat all of the above skin c4n~1itir~n~-W O 96/41579 PCT~US96/10155 SUMlu~RY OF THE INVENTION
The prcsclll invention provides a very simple easily r~ rcd sldn tre~tm~n~ procesc for (1) the re.,luv~l of sllr-o,rfi~l ep ~l-orm~l slcin celLc in the human slcin (2) the re~luch~ n or re.l.~,v~l of ullw~lcd hair and (3) the S miti~tion of skin conflihonc such as acne and seborrh~ A co~
having a high absorption at at least one wav~l~-n~h of light ic tD~ lly ~rpli~d to a sectlon of the sllrf~c~ of the skiIL A ~lefellcd cn..l~ .l is a .~ C, of 20% by weight of one micron ~hile particles in mineral oil. G~ hile, is a very strong al~soll~, of 1.06 micron light pro~luce~ by the Nd:YAG laser.
10 Portions of the co..l;~ .l are forced to infiltrate into spacec bet~,vccn thes~lrerfi~l ep:de~m~l cells, into hair ducts in the skin and into and/or ~ ent to seL-~eollc glands. The skin se~hon is ill.. ;.. ~led with short laser pulses at the m:lt~ in~ w~L~ len~h, SO as to impact snm~ent energy to the co..~
to cause eYplo.cinn in the CQ~ The energy re~ce~l in the course of 15 the ~Yplocion.c may blow off layers of dead skin cells and/or destroy tissue res~u~ le for hair growth and/or sebum prodllrtinn BRIEF DESCRIPlION OF THE DRAWINGS
FIG 1 shows a skin section FIG. 2 is a block ~ rz~n~
~;IGS. 3A-K demon.ctrate skin pee-lin~.
FIGS. 4A-E ~l~mn..cl.~les a hair removal.
FIGS. SA-C demnnctrates an ~lt~ ;vc hair lClllJV;dl and acne process.
FIG. 6 ~3emo~ es a tre~tm~-nt wherein the hair is re..luvcd prior 25 to appli~tlon of co.l~

DET~T~ ~.n DESCRIr~ON OF PREFli ~R~n EMBODIMENTS
I~cfellcd emboAim~-nt-c of the present invention can be decrribcd by rcfcrc.,ce to the drawings.

Nd:YAG l~ ~ AND CARBON PARTICLES IN OIL
Skin Peeling Outer Layers of the Epiderm, s A first ~-erellcd çmhodimPnt of the ~lC~ invention can be S described by rcrele~lce to FIGS. 3 through 3J. FIG. 3A shows a typical cross seC~on of a ~ctit)n of the outer portion (the top three strata) of the human epitlPrmic such as that in the skin of a 50 year old fernale's cheek. Shown i_ arepres~P-nt~t;on of a 15-cell thick slldlulll cornPl~m 1, and a 3-cell thick ~lldlu~ll ln~lm 2, and a 3~ell thick s~ gr~mllosllm The total thi~nPcc shown is 10 about 100 microns (0.10 mm).
Individual cells of the Sll'dLUII~ CO~ have flim-on.ci~nc of about 10 to 15 microns long, about 5 microns wide and up to 2 microns thick. The cdls of the upper layers are loosely stuck togethPr. Spaces between the cells range from zero ~ to about 1 or 2 rnicrons.
Application of Carbon Solution The first step of this ~efe~cd e-mho~lim~-nt is to top~ ly apply a layer of carbon sollltion to the skin snrf~e as shown in ~;IG. 3B. The solllhon is co~ l,sed of 1 micron graphite powder in baby oil. The ~a~hilc-oil ratio is 20 ~Jercc-l~ ~a~ e sllcrçn~le~l in 80 percent oil by weight. The next step FIG.
20 3C, is to force some of the carbon particles down below the snrf ~e of the ~ldlulll cornollm We prefer to do this with an ulllasuu-,d unit o~c ali~g at 0.2 watts per cm2 and 10 MHz.
We use a Hewlett Packard Model 3325A pulse ~c"~ or and a Par~m~-tric~ tr~ncdnrer model A5525. We have found that a~ J ;~ t~ly S
25 ~ les of ultra sound tre~tmf-nt~ at this freqno-n~y will force a ~ignifir~nt number of carbon particles down through several layers of the .711d~11111 c~ rn~llm The result of the ultr~olm~l tre-~tm-ont is shown in FIG. 3D. This distribution of carbon particles has been ~ dted on pig skin.
Microscopic ~ l ;on of biopsy s~)le~ from the pig skin show the 30 distribution ~epi~te~1 in FIG. 3D. As shown in FIG. 3D, two layers of ~ ile W O 96/41579 PCTnJS96/10155 particles are left on the s~ r~ and a portion of the particles 6 are ~ tribute~lbelow the s~ re~
Pulse Irradiation The next step is to irradiate the skin sllrf~ce with Nd:YAG laser S pulses of about 3 J/cm2 at a wavel~n~th of 1.06 ~m. Pulse ~C~lUGll~ is about 5 Hz but we scan the beam so that each lnc~tinn is ~ul~;et'~~ to pulses at a frequency of about 1 Hz. C.~"le is very absoll)livG of laser energy at the 1.06 ,um wav~l~n~t~ The latent heat of v~ inn iS about 105 J/cm3 for cold solid a~al,hile. (The energy required to heat room tempel~lu,e ~hile 10 to the sllhl;---;--A~;n~ te~ el~luic is roughly 4% of the subl;~ ;nn energy.)Thus, to V~l~li;GC a 1 r 'cron cube (1~2 cm3) would re~lui~., a~ ely 1O-7 J. The energy falling on the sllrf~r~ of the 1 micron particle (1 x 10 cm2) in a3J/cm2 pulse is 3 x 10~ J, about one third of the energy nf~etl to totally v~ . the ~ ,le. Thc-~role, a ~;~..;r;~ portion of the pa Li-,le is 15 v~li~d. The ener~y is ~lepQ~;te~l in a few n~nocec~ so there is no time for the heat to ~l;rr~e~ ~ICrerO~c~ the particle e~rlodes violently upon being ill. ";~ ~l by the pulse. (Subsequent pulses will v;~ the ~ms~ r particles clcaled by the earlier pulses.) Thus, as a result of the first pulse 7 the first layer of ~LIe 20 particles is e~rlo~lecl as sho-wn at 8 in FIG. 3E. The second layer and the skin sllrf~r~ is effectively ~hi~ Pr1 from the first pulse 7 by the first layer. Some of the carbon particles above the skin have been pushed into the skin as a result of the shocl~w~ s rçsllltin~ from the ~ n of the ~ ,lc in the first layer.
The second pulse 9 c~ min~ one second later, v~.~ the second layer as 25 shown at 10 in FIG. 3F. As before, ~irlitirm~ ,lcs are pushed into the skin. The skin is fairly effectively ~hiPl~lç~ from pulse 9 by the second layer.But the third pulse 11 interacts with the skin and the carbon ~hLcle below the skin. Laser energy at a 1.06 wav~le-ng~h has an ~ I ;r~" length in hurnan skin of several millim~t~rs but it is high~y absorbed in the ~hile ~uLicl~s below 30 the s~lrf~ce and upon al~so.~lion of the energy from third pulse 11 as shown in FIG. 3G, the ~L les P~rlnrlP violently l;pping off the dead CdlS of the sll~d~ - .. which lay above the; , '~ling cells all as shown in FIG. 3H.
A few ~al~i.les may be ~hiPl~lPIl from pulse 11 but three of four sldrlitinn pulses 13 will assure that e~ lly all ~dlJhile ~licles are ~ l k '-' as S shown in FIG. 3I.
FIG. 3J shows a cross section view of the skin s~ re after the laser irr~ hon T_is dldwil~g is based on pig skin biopsy results of skin llcdlGd as descnbed above. The skin is washed lightly with an s~lrnhnl S~l'f~51 cloth and allowed to dry rPslllhn~ in a s~ r~ as shown in FIG. 3J. The depiction as 10 shown in FIG. 3J can be cc....~ cd with that of FIG. 3A. We see that about three layers of the dead cells in the slldtL~ ... have been removed. We have 01~5~ lvGd similar effects on human skin tissue in CO--~f-~ with hair rcll.uv~l clinical ~A~ P.nSC, For most ~ , there is no pain, and no nnplr~cs-nt feeling of heat. There is no cignifir~nt injury to the skin tissue.
15 The Nd:YAG laser energy which was not al~s~,.bcd in the carbon is h~rmlesc y rl;C~ te~l in the skin and tissue below the skin. It is ~l~reldble to provide a slight divel~lg beam to assure that it spreads after it hits the skin. In our ~lGrGlled embo~limP-nt the spot size at the s~ rP is 0.5 cm (~ ,te.) and, before interacting with the skin, is spreading at 10 degrees.
Prelimina~y Biopsy el d-~
Biopsy studies of both pig and human skin cnn~ cte-l SiA weeks after t...~ l co..l;..~. that there is no Q;g~ injury to the skin. Our prelilni~-A.y conrlllcinnc from these studies in-lir~te new ~ll~en fiber r~- ~l;on in the upper part of the der nis immçrli~teiy below the epi~ermz~l 25 basal mPmhrane. These prel; ; ~ ~ observations inrli~te an ablln~l~nr~ of fi~ers which are long, wavy and bound together. There appears to be an increase in the portion of young cnll~g.on fibers in the s~ We also observe what appears to be an increase in ~l~cmocytes and young ril~ es.
These prel;...;..~.~ ol)s~ .v~lions in-lir~tç a ~o~ effect of the h~l .. ~1 in 30 the upper layers of the dermis tissue. We have not yet developed an W O 96/41579 PCTAUS96/lOlSS

PYpl~..A~ -. for this in~lirAte~l effect and we do not yet have s l"- ;~ Al data to ~lu~li~ the results.
Hair Removal E;IGS. 4A~E de."~ l of the skin for hair lcl~luv~l. In S the ~loce~s we use one of the same ~Iu-es of one micron m~Air~l grade carbon (~lJhilc) particles and mineral oil as we discuss above with f~ ~ l to skin pepli~ The cnmrn~;hnn is about 20% ~d~hilc by weight.
The hair in the to-be-treated is cut with a barber clipper to about a length of about S ~ from the skin sllrfAr,e. The ~ lul~ is applied to the 10 area to be llealcd. The ~iAlufe is m~aEP~l into the skin with a cotton swab until the hair ducts in the to-be-LI~,ate.l area are infiltrated to an e~ ed depth of about 20 ,-,lons to seve~l mill;---- t~ This stage of the ~r~CGiS iS
~l~-p:~-tetl in FIG. 4A. In s~1rlitir~n to the ~IU1~ infiltrated in the hair ducts, a thin film of the carbon-oil ~ (for e~mr'~, about 100 ~A L~1GS per cm2) 15 is left on the sllrf~r~ of the skin in the area to be ll~,dled.
The area to be treated is then ;11 .~ A~1 with a pulsed laser beam from a Nd:YAG laser. rler~ll~l beam s~c~ nc are as follows:
Wavel~n~h 1.06_icron Energy per pulse 1.5 Joules Beam area 1/2 cm2 Energy density 3 J/cm2 Frequency 10 pulses per second The beam is s~ l over the area to be ~ cd with each section of the skin in the area reccivi"g about 5 pulses. The first or second pulses 25 clean s~ ;Ally all of the ~ c from the skin s~ re by violently fr~rt lring the carbon particles. By ob5e.villg how many ~ icles remain, the doctor can e~l;...~le the degree to which each area has been ll~,aled. As shown in FIG. 4A, the initial aprlir~ffnn of the carbon-oil ~lliAIulc results incarbon ~licles being de~o~i~cd about 20 ~OIIS deep in the duct. FIG. 4B
30 lG~lesents the results of the first pulse 30 shown in FIG. 4A. A shocLw~vc inthe ~ c spreads out the ll~ for several microns. More h~ , the W O 96/41579 PCT~US96/10155 violent fr~ ;n~- of the ~uLcles sends fr~m~-ntc ll~uu~ the duct. (FIG.
4C shows qualitatively the di~ uLiûn of ~liClGS after about 2 pulses.) Ho~ ,r, with each fra~.~ n, the particles get ~m~llPr (FIGS. 4D and 4E) and after about 4 or 5 pulses 30 L:uuu~ 36 the fra~n~ontc have e -lly S d;~,~,Garcd. F~r~nh~11y all of the energy absorbed by the particles and fr~n~ntc is ll~relled to the skin tissue sullu~ lin~ the hair. The net result is depicted in FIG. 4E. The energy is s~ r;~ont to devitalize the ti_sue f~c e~
the hair so the hair dies. In FIG. 4A l1LrOU~ 4E arrow 38 locates the seL~ir)n of skin tissue ~l~m~e~l Our biopsy tests in-lir~Se the thirlrn~cc of the ~ m~
10 sectirn-C range from zero to about 20 i~,ro~s. The ~1~m~ to the tissue a~ , to be the c~)mhine~l result of both the 1~ , effect of the hot carbon particles and oil and possibly some mPrh~nir~ m~ee due to the kinetic energy of the ~Lcles and fr~pm~-n~s We have had eYr~ -nt results with our human tests. In an early 15 c 1. - ;..~ u~ with this i~ uved ~ce~ on my own leg P rss ~ lly all hair was re,lluvGd and after 24 m~mth~ there has been no ci~;--iri~A--I lC~uwlL. Our clinical trials with facial hair have been on-going for 24 weeks. We have been very <~On5_1V~lliVG in the applir~ti~n of the laser beam, but the results are very good. No ~ignifir~nt short term injury to the skin has been ol~s~ d (only 20 minor redness and in a very few cases some very rninor ~lr~'in~). No long term injury has been observed. Hair removal s~lrr~ss ratio in the treated area has ranged from about 0% to about 90% with the average being about 60%.
Treatment for Acne and Seborrhea Our ~1~,re11~.d process for ll~~ of acne and se~. .1.~ is 25 b~;r~lly the same as the llc~l~..rnt for hair le.llOV;~l and skin I~er~ g. The import ~lirre1GllcG being the sectirn of skin lleated is one in which the patient s has had problerns with acne or sebnrrhe~ P1c;rer~b~, the ~ .. rnt is s~he~lllle~l when the ducts to over active se~-~eous glands are open. The carbon solution ~l~srrl~etl in the prece~ling secti~ ~ is applied and caused to 30 infiltrate into the duct le~ling to the seb~reous glands as shown in FIG. SA~

WO 96/41579 PCT~US96/1015 The pollioll of the seb~r~oll~ glandls is also shown in FIG. 1. Laser ill---";--~l;nn is ~ "~ ly the same as for hair l~ lUV;:lL The carbon ~licl_s wi~hin or in the vicinity of the se~ --e ~ glands are heated to v~ inn C1~ eS which causes the ~ ,s to fracture violently or V;~
Energy r~ e~l in the process results in full or partial destruction of epit~ lm tissue m~hn~ up the s~ re of the inside wall of the se~--e~
glands which tissue, produces the sebum. This results in either death or re hlre~l err~Lvcness of the seb~r~oll~ g1ands in the section of skin tlcaled.
The consequence is a redur,e-l sebum pro~luct~rln The col,se~l-,.,nce of recluce~
sebum prod~ n is redYced levels of acne and sebo. ~

CON~;INEMlENT OF PARTICLES
Another ~JlGÇGll~i ~omh5)11imPnt for skin l1G ~ -1 iS the same as the first ~lercllcd emhorlimpnt except lhat after the carbon-oil :iUD~cl~ion is placed on the skin s11r~r~, a thin flat piece of glass (such as a J li~lUSc~J~
glass) is placed firmly over the ~ ~~-~.-;n~ in order to c~ ..1;.~, the small PYp1n~;nne Several pulses (~ierG~dbly about 1 or 2) of the laser beam are applied ~ou~h the glass onto each section of ~u..~cl~ion~ The effect is to greatly rnh~nr~ the ~ r;1r~ cr...~ l;nn of the upper layers of the epi;lermie with small particles of graphite. The effect is shown in FIGS. 3K
and 3L. One or two pulses is ~ ie.~l to produce sn~ .bi,... r~
c~ ;nl~ with small carbon particles. After this applir~inn the glass is removed and the p~ce~ as Pypl~inp~l above for the first çm1~1;.. ~L is cn~ ,ell until e~ 11y all of the ~d~hile has been Vd~.. ;,.,t1 In an e Pmh~irrf~nt a disposable plastic plate, h~alenL to the laser beam could be used inete~ of the glass plate. The disposable plastic plate could be made a part of an arh~ ted arm of the laser or a part of a hand piece ~tt~rhP~ to the arhr-lll~te~l arm.

W O 96/41579 PCTrUS96/10155 Athird~l~rGl~d e ...1~1;."~ utilizesa C ~2 pulselaser. Fl~re"~i o~a~ g ~ are: wavel~rlgth 10.6 micron, energy density per pulse 2.5 Joule/cm2, pulse fliA,, If-~ 1 cm, pulse rlll~hnn 50 ns. Laser beams at 10.6 S micron have an . - l ;... ~ ;nn length in skin of about 40 micron bcr~ ~ the pulse energy is highly absorbed in water. It is much more highly a~soll,cd in carbon.
We e~ .A~e an ~ l;on length of 1 to 2 microns.
The ~rocess is very similar to that dcwll~Gd above. Cla~LIc is applied as above using the ulll~s~ d to force some of the carbon below the 10 sllrFAr~ The laser pulses are applied as above and to the first t~,vo pulses produce similar results rl~Aning off the two layers of carbon. The third pulse lluwever will in ~rl~litinn to V~ g carbon below the skin s~ r~ will v~ ~ a thin sllrfAre of tissue. ThGrerLlG, we get the cc~ effect of (1) n~f~ Al rel,luv;ll of tissues due to the ~ I 'o~ n of ~licles below the 15 sllrF~r~ and (2) v~ l of a snrf~r~ layer of ep ~ l tissue about 2-3 c~olls thick LIQUID CONTAMINANT
Tncte~r1 of the carbon oil ~IU1G ~ c ~C~ell above, we could use other liquids or ~USpG~ such as India ink. India ink is cn~ ; c~l of very 20 small submicron graphite particles su;,~Gllded in a liquid such as a water snll~tinn of ~lrnhnl We may also use a snllltinn of warm water colored with black food c~l~rin~ at one part color per fifty parts water. Apply to skin snrf~re with gauze for 10 ...i.,~ s The cont~min~nt will infiltrate into the space in the upper layers of the corneum s~ ulll. CI~hese spaces are nnrm~lly 25 filled with air.) Remove gauze and ill-----i--~te with about 1 or 2 pulses per site using a CO2 laser ~Gldlillg at 10.6 microns and 50 nzlnnsecnnfl duration pulses with an energy density of 2 Joules per cm2. These short pulses will deposit sllffiri.ont energy selectively to the c~ solution to v~ in~z~ntly the CC I-~ -lt tearing off the upper most CUI11GUI~ :illdlUlll cells in the skin 30 sectinn W O 96/4157g PCTAUS96/10155 An ~llc~ ;vc to this emho~im~nt is to add indo. ~e green to the warm water in~tç~l of the black food cn'~ring Indo~ e green absorbs i~cd light such as that ~ P~ by the Nd:YAG, CO2, ~1f~Y_nr1r;t~., Ti:
~ and Ga:As diode lasers. Since water is an ~Yr~ nt absorber of C ~2 S laser energy, many water based skin lotions could be used with the C ~2 laser.REMOVAL OF HAIR (PART~ALLY OR FULLY) FROM DUCI
A ~ ,rcll~ erAho~lim~nt of this in~enlion for hair r~ v~l and for acne 1.~ is sho~-vn in FIGS. X A, B and C and 6. FIG. 5A depicts 2 hairs on a skin section showing hair stem 33, hair duct 31 and the s~-Aeol~C gland 10 38. As shown in E;IG. SB the hair is partially l~ UVCd from the hair duct below the skin s~ Ae by chomiA~l depil~h~-n The carbon s-llltinn is then applied to the skin section and rubbed into the skin. In this case, since the upper part of the 50 micron ~ r hair is gone, there is much more room in the duct for the srlnh~n with 1 micron ~alLi les as shown in FIG. SC The 15 skin secti~ n is ill~....;..~ler1 as .1~ ed above but in this case the ~r~ss is much more c~ Livc for hair tissue destruction and se~r~us gland tissue destruction 1,cc~ c there is a far gr~alcr ~ua.llilr of carbon particles initially in the duct.
FIG. 6 shows a hair duct in which the ~..~ Ic hair has been 20 ~nmpletely n ll.uvcd by a m~thnd such as phlr~in~ or by extraction with hair extraction wax. Here an even greater ~lua~ r of carbon ~ les can be infiltrated into the duct for even more c~T~. Iivc~less. A good mPthn 1 of removing the hair in ~lc~lion for the laser tre~tm~nt is as follows:
Place a thin layer of super glue on a 2 cm2 section of a glass 25 mic.usco~e slide. After five seconrl~ place the treated section of the slide on the skin area to be llcatcd. Leave on the skin for 30 sor~nA~ Lift the slide.
This will pull out all hairs by the roots. The ducts can then be infiltrated with cr...~...;..~.~l as ~ c ~c~l above.

OTHER EMBODIMENTS
P~,,~lls skilled in the laser-m~Air-in~ art will r~ that many other lasers~ 4..n~ could be used to pr~chr~ this i~ nLiul..
The Ul~ attributes of the cr....h;~ are:
S 1) The C4.~ 5i.1l must be very highly absul~livc of energy at the wavc~ - of the laser beam when using small ~ li.,les, the ~ li ,les ~rercl~bly should be ~m~llP,r than 10 ~ ,luns.

2) The laser beam prerclably is a pulsed beam with very short pulses (pulse ~ iull of less than 1 . ..ilusecnn~
0 3) The cn~ --l should be c~p~bl~ of being infiltrated into spaces in the upper layers of the skin.
4) The ~".I;1".;.~ should eqllo~le with ~--rril ~nt energy upon absorption of the laser energy to produce the desired results.
Appli~nt~ have tested acrylic tattoo inks which have becen a~plo.e~l 15 by ~ A for tattoo use. Black and blue tattoo inks ...~ by ~;p~ ing and Rogers a~ar to work well with a Nd:YAG laser c,~Glaling at 1 Hz, 1.06 micron with an energy density of about 3 J/cm2. We had less ~.,cc~,ss with other colors. A~ has also ~. r.. ~ A~ Glll:i using black powder which is a very finely ground llliAll.ue of pot~ m nitrate, carbon and sulfur.
20 This ~i~lUlC . ~odoc ~ lly when ill.. i.. ~le~l with 10 ns, 2 J/cm2 Nd:YAG laser pulses. The ~JUl liol~s of the above ch~o-mir~l~ in black powder may be about 75% KNO3, 15% carbon and 15% sulfur.

While the above ~Per,il.lion ~,,~5,j,,c many sperifir~ti~n~ the reader 25 should not CO1IDI1UC these as li~ on the scope of the hl.clllioll~ by merely as eYomrlifir~tir~ne of ~l~rGllcd embotlimlo-nte- thereof. Those skilled in the art will envision many other pn~ v~ri~hrm~ are within its scope.
Accol.lil,~ the reader is re-lue~l6d to delc ~ ...i..~ the SCOPG of the invention by the appenrlP~3 claims and their legal equivalents, and not by the ~ ~ ' 30 which have been given.

Claims

We claim:

1. A skin treatment process comprising the steps of:
a. topically applying to a section of skin a contaminant having a high absorption, at at least one frequency band of light which penetrates outer layers of human epidermis, b. forcing some of said contaminant to infiltrate into spaces in the skin and c. illuminating said section of skin with pulses of said at least one frequency band of light, so as to impart to the contaminant sufficient energy to cause at least a portion of said infiltrated contaminant to explode.

2. A process as in Claim 1 wherein said contaminant comprises a large number of carbon particles.

3. A process as in Claim 1 wherein an ultrasound device is utilized to force said some of the small carbon particles to infiltrate into said spaces.

4. A process as in Claim 1 wherein an explosion, defining a forcing explosion, of a portion of said contaminant is utilized to force anotherportion of said contaminant to infiltrate into said spaces.

5. A process as in Claim 1 wherein a confinement means, transparent to said at least one frequency band of light is placed firmly over said topically applied contamination for the duration of said forcing explosion for the purpose of confining said forcing explosion.

6. A process as in Claim 5 wherein said confinement means is a glass plate.

7. A process as in Claim 5 wherein said confinement means is a plastic plate.

8. A process as in Claim 7 wherein said plastic plates is a part of an articulated arm.

9. A process as in Claim 1 wherein said small carbon particles are small graphite particles.

10. A process as in Claim 9 wherein said small graphite particles are mixed with an oil.

11. A process as in Claim 10 wherein said oil is baby oil.

12. A process as in Claim 2 wherein said small carbon particles have major dimension of about 1 micron.

13. A process as in Claim 2 wherein said laser pulses are pulses from a Nd:YAG laser.

14. A process as in Claim 2 wherein said laser pulses are pulses from a CO2 laser.

15. A process as in Claim 1 wherein said spaces in said skin comprise spaces in hair ducts in said skin not occupied by hair.

16. A process as in Claim 15 wherein said at least one of said pulses has sufficient energy to destroy tissue feeding hair growing in said hairducts.

17. A process as in Claim 15 comprising the additional step of removing from said ducts a portion of a plurality of hairs in said skin section prior to applying said contaminant.

18. A process as in Claim 15 comprising the additional step of removing from said ducts substantially all of a plurality of hairs in said skin section prior to applying said contaminant.

19. A process as in Claim 1 wherein said spaces in said skin comprises spaces between superficial epidermal skin cells.

20. A process as in Claim 1 wherein said spaces in said skin comprises spaces within sebaceous glands.

21. A process as in Claim 2 wherein said spaces in said skin comprises spaces adjacent to sebaceous glands.

22. A process as in Claim 1 wherein said contaminant is a chemical explosive.

23. A process as in Claim 1 wherein said contaminant is black powder.

24. A process as in Claim 1 wherein said contaminant is a mixture of potassium nitrate, carbon and sulfur.