Introduction to Lasers

Anyone who knows me willtell you that I entered thisarena with my eyes wide openand with a quest forknowledge. I had a medicaland dental background, abuilding block for the field ofaesthetic medicine, but didlasers (light amplification bystimulated emission ofradiation) enter into my head?Initially no, never, but what Ihave witnessed first hand isthat lasers are fast becomingthe ‘new kids on the block’,producing life changing resultsfor patients and cliniciansalike. Lasers certainly need tobe on the menu for thoseclinicians who want to beahead of the game.

Education is key andknowledge is power. Mymessage to all of you is this:don’t be left in the dark, letthere be light!

A buyer’s guide to lasers and light systemsUnlike man, not all lightsystems are created equal!Therefore, it is critical tounderstand their explicitsciences when researchingspecific products. First andforemost, all technologies havetheir niche applications andspecialties but in most casestheir overall differences arenegligible. Nevertheless, havingan accurate understanding oftheir variations can help yousecure a unit destined todeliver desirable results,meeting both patient andpractice demands yet notbreaking the proverbial bank.

It’s all in the family – the diverse laser mediumsThe tell-tale technology detailsof the different types of lasers,complete with their variouswavelengths, are diverse. Thelaser medium can be a solid, agas, a liquid or a semi-conductor, with laserscommonly designated by thetype of ‘lasing’ materialemployed.

Solid-stateThese lasers have lasingmaterial distributed in a solidmatrix of crystal, examples ofsuch being the ruby oreodymium:yttrium-aluminumgarnet (aka YAG lasers). Theneodymium:YAG laser emitsinfrared light at 1,064nanometres (nm).

The ruby laser is primarilyknown for tattoo removalprocedures. It consists of aflash tube (like you would haveon a camera), a ruby rod andtwo mirrors (one half-silvered).The ruby rod is the ‘lasingmedium’ and the flash tubepumps it. The ruby laser worksby producing short pulses ofintense light that passharmlessly through the toplayers of the skin to beselectively absorbed by thetattoo pigment. This laserenergy causes the tattoopigment to fragment intosmaller particles that are thenremoved by the body'simmune system. The laserselectively targets the pigmentof the tattoo without damagingthe surrounding skin.

The Alexandrite (crystal)laser produces reddish lightjust at the limit of visibility, at

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LLLL eeee tttt tttt hhhh eeee rrrr eeee bbbbeeee llll iiii gggghhhh ttttTracey Bell presents anintroduction to lasersand light therapy

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755nm, and is suitable forrapid hair removal treatmentsin patients with light to olivecomplexions.

Gas lasersThe carbon dioxide laser (CO2

laser) was one of the earliestlasers to be developed(invented by Kumar Patel ofBell Labs in 1964) and is stillone of the most useful.

Carbon dioxide lasers arethe highest power continuouswave lasers currently available.The CO2 laser produces a beamof infrared light with theprincipal wavelength bandscentring around 9.4 and 10.6micrometres.

Today the CO2 laser has beengiven a ‘make-over’ with itsstate-of-the-art ‘fractional’ twist.This application drills a microbeam matrix-style spot size tothe target area, leaving voids ofhealthy tissue intact to facilitatehealing while capitalising on thethermal energy and resurfacingbenefits. This new generationtechnology penetrates about100 microns deep to activatecollagen remodelling at thedermal/epidermal juncture andis indicated for deep acnescarring and wrinkles.

Semi-conductor lasersSometimes called diode lasers,this type of laser is not solid-state. These electronic devicesare generally very small, uselow power and could be usedfor hair removal or on LEDdevices.

Their main claim to fameNothing is better for hairremoval than lasers! Severalwavelengths of laser energyhave been used for thisprocedure, from visible light tonear-infrared radiation. Theselasers are usually defined bythe lasing medium used tocreate the wavelength(measured in nanometres(nm)). Fluence or energy level,measured in joules per squarecentimetre (J/cm2), is animportant consideration as wellas laser wavelengths, withlonger wavelengths safer fordarker skin types due to lessmelanin absorption: • Ruby: 694nm, suggested forskin types I to III• Alexandrite: 755nm, the‘gold standard’ for skin types Ito IV• Pulsed diode array: 810nm,the ‘gold standard’ for skintypes II to V

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• Nd:YAG: 1064nm, suggestedfor skin types IV to VI.

However, less absorptiontranslates into an efficacytrade-off, thus epidermalcooling allows for higherfluences while reducing painand potential side effects, withdarker skin types at thegreatest risk.

Four types of cooling havebeen developed, which are: 1. Clear gel – usually chilled(messy) 2. Contact cooling: through awindow cooled by circulatingwater (expensive) 3.Cryogen spray: immediatelybefore/after the laser pulse(expensive) 4. Air cooling: forced cold airat -34ºC (Zimmer Cryo-5unit), an excellent coolingmechanism but expensive atseveral thousand euros.

The primary principlebehind laser hair removal isselective photothermolysis.Lasers cause localised damageby selectively heating darktarget matter in the area thatcauses hair growth while notheating the rest of the skin.The foremost chromophore forlaser hair removal is eumelanin(the specific melanin that givesbrown or black hair its colour).Since lasers that are intendedfor topical use can onlypenetrate skin tissue a fewmillimetres deep and there aremultiple active growth haircycles within the body, legallypractitioners arrive at theexpression permanent hairreduction as opposed topermanent hair removal.

The spot size of the laserbeam also affects its treatment,theoretically with the width ofthe ideal beam about fourtimes as wide as the target isdeep. Most lasers have a roundspot about the size of yourlittle finger (8-10mm).

The downside of lasers forhair removal is that they couldcompromise the comfort levelof the patient and they areexpensive. The top of the rangesystem features the best thatmoney can buy, encompassinga customisable ‘platform’ unitcomplete with multipletechnologies. Diode and YAGlasers, as well as IPL (intense

pulsed light) and radiofrequency, are housed togetherwith an exclusive upfrontpricing plan for a whopping€150,000 if ‘fully loaded’, withnew technology upgradesrunning from €20,000 to€40,000.

Laser tattoo removalAlmost any tattoo can now beremoved with the use of lasers.The treatment works bybreaking down the particles ofink suspended beneath theskin, enabling your immunesystem to eliminate themnaturally. Several types oflasers and wavelengths areemployed to remove differentcolour groups and the specificlaser pulses are directed ontothe tattoo, breaking up thepigment. Over the next severalweeks the body’s macrophagesremove the treated pigmentedareas. Generally, from threeand up to 12 monthly sessionsmay be required and treatmenttimes vary according to thesize of the tattoo, which cantake anywhere between 15 and45 minutes.

Non-ablative, ablative and fractional rejuvenationThe new generation of laserresurfacing technologiesremoves the upper layers ofskin via target tissuevaporisation while harnessingphotodynamic energy tosmooth out fine lines andwrinkles, revise scars or totreat irregular skinpigmentation.

The most conventional areeither non-ablative (mild) orablative (deep) applicationswithin the Erbium YAG familyof lasers that is a 2940wavelength on the infrared orinvisible side of the lightspectrum. My approvedarsenals of lasers include theWhisper Extended AblationLaser Peel, the HarmonyErbium YAG Laser and thePixel.

The Whisper Peeltechnology is specificallyindicated for pitted acne andkeloid scarring, lines andwrinkles, mild hyperpigmentation, and collagenremodelling for natural skin

Figure 1: Wavelengths of different types of laser

Figure 2: Apsorbtion rate according to wavelength in nanometres

Figures 3 to 6: Before and after intense pulsed light (IPL) treatment

durations) and focusing optics.By using ‘filters’, thewavelengths of light emittedfrom these devices may beweighted toward the longerwavelengths (400-1200nm) foruse in hair removal as well asother applications.

The large spot sizes and fastrepetition rates make rapidtreatment of large areaspossible. However, becausemost of the light energy is inthe shorter wavelengths,treatment of darker skin typesis less effective and more riskythan with the appropriate laser.

Second generation IPLapplications may be indicatedfor rosacea, port wine stain andacne clearance treatments,micro/thread and varicose veinremoval, skin tightening,hyperpigmentation, cellulitereduction therapy and more.This new technologyincorporates ‘dual modefiltering’ and other importantadvances that result in saferand more effective treatmentthan the older systems, which were initially designedfor simple processes such ashair removal.

The focused, broadspectrum light is applied to thesurface of the skin by way ofeither a hand-held wand or byan articulated arm. The intenselight travels down the hairshafts, where it strikes thebulb, or root, of the hair. Thebulb is usually where thehighest concentration ofmelanin is located, as opposedto the rest of the hair shaft.When the light strikes the

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dark-coloured melanin, thelight is converted to heatenergy. The bulb and most ofthe hair shaft is instantlyvaporised. The intense heatradiated by the hair alsodestroys the hair-producingpapilla or the entire hairfollicle. It is also claimed thatdirect light-heat conversionoccurs directly in the darkercoloured capillaries that bring nourishing blood to the follicle.

The pulses of lightproduced by IPL equipmentare very short in duration, sodiscomfort and damage tonon-target tissues is minor.Most people who undergo IPLepilation only experience slightirritation similar to that ofminor sunburn, althoughunder certain circumstancesblisters may occur. The lightthat emanates from the IPLwand is filtered to remove anyultraviolet (UV) components,eliminating the possibility ofUV skin damage.

With IPL, external coolantsare still recommended andalthough you won’t be diggingquite as deep into yourpockets, you will still need toreach for at least €50,000 toinvest into a reasonably soundsystem if you want thepristine package.

A final noteCombined with othertreatments such as chemicalpeels, microdermabrasion,radiofrequency, fillers andBotulinum toxin, lasers are thenew kids on the block.

rejuvenation. It is equivalent to12 micro-dermabrasions pertreatment delivered with microprecision and control forsuperior results. It requiresthree to five sessions over athree- to five-month period foroptimum results but can alsobe used as an in-between timebeauty boost. The patient canexpect anywhere from three tofive days of downtime for anintensive ‘arctic’ peel or nodowntime for a lunchtimeexpress rejuvenating ‘LitePeel’.Full facial treatments or localregion sessions can beaccomplished with nodiscomfort.

You can, however, dare togo deeper with the ‘rapidresults’ Harmony Erbium YAGlaser. The Harmony isindicated for the sameconditions on more severecases. The treatments can takebetween 30 minutes to an hourand the recovery time is five to10 days.

Pixel Photo Rejuvenation isa safe and effective treatmentfor fractional ablative skinresurfacing on the face, neck,chest, arms and hands. It isdesigned to treat aged andphoto-damaged skin, and toimprove the quality,appearance and texture of thecomplexion while itstimulates collagenregeneration. The skin aroundthe treatment area feels firmerand tighter with a smoothersurface texture. It is premisedon micro beam technologyand is intended as a gradualprocess protocol that happensover several treatments.Approximately three to fivetreatments are recommendedat bi-weekly intervals andtake around 45 minutes withno recovery time.

Alternative solutions: powerful and profitableIntense pulsed light (IPL)devices are not lasers, becausethey emit broadband, non-coherent light of manydifferent wavelengths from axenon flash lamp (an electricglow discharge lamp designedto produce extremely intense,incoherent, full-spectrumwhite light for very short

Table 1: Laser applications

• Hair removal

• Tattoo removal

• Skin resurfacing

• Peri-oral rejuvenation

• Peri-orbital rejuvenation

• Rosacea treatment

• Acne and large pore treatments

• Photo damage

• Fine lines and wrinkles

• Skin tightening

To compare prices and product

performance, visit www.miinews.com

Dr Tracey Bell is founder andCEO of TRACEY BELL. Acosmetic dentist and aestheticphysician, Dr Bell started herfirst dental practice,Craigend Dental, in the Isleof Man in 1995. Six yearslater she expanded intoaesthetic medicine, launchingThe Kensington Clinic nextdoor to her dental practice.The first TRACEY BELLclinic, her ‘body shop for the21st century’, was opened inDouglas, Isle of Man, inOctober 2006. Then, in June2007, she launched a 7,000 sq ft medical spa inLiverpool, offering dental,non-surgical, laser, spa, hair,body shaping, SkinScriptionand mineral make-uptreatments. Dr Bell isrecognised by both the dentaland aesthetic industry as apractitioner of internationalstanding and is aninspirational speaker notedfor her motivational andauthoritative presentations.

Figures 7 and 8: Before and during treatment for tattoo removal