Light Based Systems for the Modern Day Salon/Spa

Typical Uses Today

Evolution of Lasers

Laser

• What is laser.
• How does it work?
• Name different types and their uses.
• Side effect profile.

IPL/VPL

• What is IPL.
• How does it work?
• Different applications.
• Side effect profile.

• History of company.
• Technology used.
• Independent studies.
• Demo on one self.
• References.

Generally there are two main groups of light based systems namely laser (Light Amplification by Stimulated Emission of Radiation) and IPL (Intense Pulse Light) that has a number of uses in the aesthetic world of today. Most commonly the demand for these machines is seen with hair removal, alternative acne treatment, skin rejuvenation, wrinkle removal, and skin tightening. I believe it is important to understand the technology behind each machine group so that you can make an informed decision in which machine to purchase to meet the demand for specific target markets. I will start with lasers then move on to IPL based machines, discuss new technologies and finally compare the efficacies and side effect profiles and complications that one could experience with treatments for each machine group.

Light

Light is a form of energy and is part of the electromagnetic spectrum – different forms of energy that spread out as they travel. As we all know light is made up of a number of different colours, and each have their own specific wavelengths. These wavelengths also have different energies that effect how far the light can travel and therefore the effect they will have on the skin. Shorter wavelengths have a more superficial penetration while longer wavelengths have a deeper penetration. The effect achieved in the skin is through a mechanism known as selective thermolysis. In 1983 it was found that it was possible to selectively target a particular chromophore (melanin and haemaglobin) by choosing the appropriate wavelength. A progression of this term is photothermolysis where the light or energy is absorbed into the skin through chromophores (melanin and haemaglobin), the transformation of light or energy into heat, and the destruction of these target cells by the heat created.

Laser

All lasers work using a similar basic principal. A box called a resonator containing a medium or an active element specific to the type of laser – solid (ruby, Nd-YAG), liquid (dye lasers) or gas (CO2, argon, helium, neon, krypton) will produce light characteristic for the atoms or molecules within the resonator. As power (mechanical, electrical, chemical, radiowave, etc.) is introduced into the laser, atoms or molecules are elevated to a higher energy state known as the excited state. Since the excited state is unstable, electrons spontaneously return to the resting or ground state, emitting energy in the form of photons. The resulting photons released (stimulated emission), have identical wavelengths and frequencies traveling in the same direction and are spatially and temporally in phase. These photons are reflected back and forth between the partially reflective mirrors at each end of the resonator box. Continued absorption of energy results in further stimulated emission and ultimately in light amplification and the production of laser light. The light, once produced, enters the laser delivery system, which for most lasers is quartz fibreoptics, and finally to a hand piece with a focusing lens.

Lasers usually produce light of the frequency and wavelength between the infrared and ultraviolet parts of the spectrum.

The wavelength and frequency of the light generated is dependant on the element contained in the resonating chamber.

Light produced by lasers has several unique properties:

Some laser terms:

The energy produced is measured in joules.

Power is measured in Watts – this is joules/second.

Thermal relaxation is the time taken for a tissue to cool to 50% of its temperature achieved immediately after exposure to laser energy.

Fluence is the energy delivered per unit area. It is used to describe pulsed lasers.

Irradiance is the power delivered per unit area. It is used for continuous wave lasers.

Continuous lasers produce a continuous wave of laser light that can be gated or shuttered but the pulses produced are greater than the thermal relaxation time.

Pulsed lasers are designed to produce very short pulses of high intensity light. These pulses can be made shorter than the thermal relaxation time.

Q-switched lasers have even higher intensity pulses of shorter duration.

The effect of a laser is dependant on the:

• Wavelength – increase wavelength increase penetration.
• Fluence – the higher the fluence the greater the penetration.
• Spot Size – the greater the spot size the greater the penetration.
• Pulse Duration – the longer the pulse duration the greater the penetration.

On interacting with tissue, laser light may behave in various ways:

• Reflection – directly from the surface of the tissue or indirectly from deep reflective chromophores (usually collagen).
• Scatter – may effect surrounding tissue.
• Transmission – passes through the tissue.
• Absorption – most is absorbed and thus exerts its clinical effect on the tissues.

Types of lasers:

Ablative Skin Resurfacing – C02 and Er:YAG (erbium: yttrium-aluminium-garnet)

Absorbed by tissue water.

Most commonly used resurfacing lasers.

Removes the outermost layer of photodamaged skin to varying degrees, and through normal wound healing this ablated layer is re-established. Healthy epidermis migrates from adjacent tissue and adnexal structures, and new collagen and elastic tissue are deposited by activated fibroblasts – 6 to 8 months of remodeling.

C02:

• Penetrates approximately 30 micrometers.
• Because the layer of thermal necrosis contains less tissue water than normal skin, there is progressively less tissue vaporization with each subsequent laser pulse at the same impact site.
• Greater depths of tissue ablation can be achieved with the use of a higher treatment fluence and reducing the spot size.
• Produces a drier more necrotic wound.

Er:YAG

• Introduced as an alternative to C02 in the hope of decreasing the recovery period and side effect profile.
• Wavelength of 2940 nm.
• Optical penetration depth is about one twentieth that of C02.
• Both short and long pulsed types.
• Produces a moist wound free of necrotic tissue.

Post-procedure Coarse/Side Effects:

• Prolonged erythema.
• Post-operative pigmentory changes.
• Scarring.

Non-ablative Resurfacing

The epidermis and superficial dermis can be selectively damaged by two mechanisms:

By targeting discrete chromophores in the dermis or at the dermal-epidermal junction.

Using mid-infrared lasers in a range of 1.3 to 1.55 micrometers – wavelengths at which absorption by water is weak enough that relatively deep beam penetration is allowed.

These lasers have the advantage of a shorter post-operative coarse, but are generally not as effective as the ablative resurfacing lasers for re-surfacing. Examples of lasers in this group:

Pulsed Dye laser:

• Wavelength – 510 nm.
  • Used for melanin (pigmentation) and red tattoo ink.
• Wavelength – 585 nm.
  • Vascular lesions.

QS Alexandrite Long Pulsed:

• Wavelength – 755 nm.
• Used for melanin, tattoos and hair removal.

Side Effects & Complications:

• Infection.
• Contact dermatitis.
• Erythema and purpura.
• Pigmentation changes – usually occurs in darker skin (Type 3 and above) and exacerbated by sunlight (UVA).
• Acne – more common in oily skin.
• Scarring.
• Hypopigmentation – most common complication, usually late (after 6 months), most evident in skin type 1, 2 and 3 individuals, and usually cannot be reversed.

IPL Overview:

The basis of this device is that it uses a flashlamp to produce a spectrum of light from 500 to 980 nm at energies of up to 80 J/ cm². The light is produced by a specially constructed xenon flashlamp and directed to a hand piece with focusing optics.

The light can be delivered as a single pulse, or double and triple pulses in the millisecond range through a hand held aperture of various sizes.

Specific wavelengths, which range from 515 nm to 590 nm, can be emitted by using various filters.

Hair Removal/Epilation.

The normal hair growth cycle is comprised of three stages: Anagen (active growth), Catagen (transition stage), and Telogen (resting stage). All hair follicles go through these cycles in a non-synchronized manner and it is only during the anagen or growth phase that hair follicles can be destroyed. In fact all long-term epilation methods target hair at this stage and furthermore each body area requires re-treatment at different time intervals. It is important that clients undergoing epilation understand this concept of hair growth cycles so that their expectations are realistic. The following table demonstrates the duration of the resting period for different parts of the body and shows that the period between consecutive treatments should be determined by the body area being treated. The numbers in the table are an average and can be effected or vary depending on age, ethnic origin, hormonal differences etc.

All IPL based systems through the operator of the machine, should use specific wavelengths, and deliver the correct energy to destroy the hair follicle and thereby stopping future growth. The range of these wavelengths is from 680 to 980 nm. The energy is dependant on the skin type and patient comfort levels. A rough guideline is 20-45 J/ cm² for light skin individuals and 15-20 J/ for darker skin.

Photo Rejuvenation

Skin renewal or photo rejuvenation is achieved trough thermal destruction of pigments in pigmented lesions, coagulation of blood vessels and collagen heating to sub necrotic temperatures. The destroyed pigment and blood vessels are eliminated through phagocytosis. There is also an inflammatory response that is responsible for stimulating fibroblasts to increase production of elastin and collagen. The resultant effect on the skin encompasses an umbrella of results that in a nutshell can be described as a younger looking skin and a youthful glow. Visible changes will include improvement in texture, reduction in pore size, improvement of class 1 wrinkles and a clear complexion. If performed properly this treatment will be your best word of mouth referral. My approach to choosing the correct settings is two fold: skin type and patient comfort levels.

Acne Treatment

This is achieved through the destruction of bacteria by natural photodynamic therapy and hyperthermia and a resultant reduction of sebaceous gland activity and pore size.

Porphyrins are produced on the membrane and accumulate in P.acnes as part of a normal metabolic pathway in the production of the bacterial respiratory enzymes. These porphyrins absorb blue light with a wavelength of between 400 and 420 nm.

Light + P.acnes porphyrins = excited labile porphyrins with excess energy.

Excited porphyrins + stable triplet oxygen = labile singlet oxygen.

Singlet oxygen + P.acnes cell membrane compounds = impaired membrane and cell death.

This reaction is short and confined to the bacteria and has no effect on surrounding tissue.

New Technologies

Combination IPL and Radiofrequency:

The addition of radio frequency, in particular bipolar radio frequency with IPL has allowed for excellent results, quicker and safer treatment times, and less downtime for patients receiving these treatments. I believe that this is an exciting evolution for the IPL, as it will start to rival ablative lasers in the final effect that can be achieved with the skin. The term used to describe this new technology is electro-optical-energy (ELOS), which allows selective radiophotothermolysis. Recently a study (108 subjects with a total of 540 treatments) performed by Dr Patrick Bitter Jr. (2005), showed the following:

Overall skin improvement – 75.3%.

Skin laxity improvement – 62.9%.

Skin texture improvement – 74.1%.

Pore size appearance improved – 65.1%.

Average erythema and telangiectasia improvement – 68.4%.

Hyperpigmentation and dyschromia improvement – 79.3%.

Overall wrinkle improvement – 41.2%.

Class 1 wrinkles – 64.7%.

Class 2 wrinkles – 38.6%.

Class 3 wrinkles – 20.4%.

Overall patient satisfaction was 92% and the overall minor complication rate was 8.3% - blistering, crusting and stripping. The major complication rate was less than 1% - small depressed nasal scar observed in 1 patient.

Similarly, the combination of radiofrequency to the hair removal and acne treatment applicators has shown greater patient comfort, less side effects and for hair removal the ability to target light, blonde and even white hair. The theoretical reason for this is that the radiofrequency concentrates the heat in and around the hair follicle. This is achieved with the electrical current, created by the two poles of radiofrequency, increases in density within and around the hair follicle. This results in heat generated in this area to be 4-10 times higher than in surrounding tissue. Overall the safety is improved as less optical energy is needed, deeper follicles can be targeted (male trunk hair), and the ability to treat dark skin without compromising safety.

Combination Infrared and Radiofrequency:

Recently the arena for skin tightening was performed with either infrared (Titan) or single pole or mono-polar radiofrequency (Thermage). Both of these technologies work on shrinking of collagen initially producing a tighter skin, and the denaturation of collagen and new collagen formation over a longer period (8-12 weeks) providing further skin tightening effects. The combination of these two technologies has resulted in quicker treatment times, fewer side effects, and very little patient downtime and greatly improved patient comfort.

How to Choose a Supplier

Research the supplier:

Company history: both the supplier and the manufacturer.

Internet.

Avoid IPL wavelengths of greater than 1000nm – starts to heat water, thereby increasing tissue damage and side effects.

Ask for referrals of other purchasers and follow up.

Look at maintenance and service costs.

Cost per shot or treatment.

Look at your target market or markets.

Look at clinical trials and ask for independent studies performed by specialists not linked to the manufacturer.

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