MILADY S AESTHETICIAN SERIES - Beauty and … Abnormal Scarring 65 Conclusion 65 Top 10 Tips to Take...

M I L A D Y ’ S A E S T H E T I C I A N S E R I E S

Lasers & Light TherapyPamela Hill and Patricia Owens

President, Milady: Dawn Gerrain

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© 2009 Pamela Hill

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Contents

PREFACExiii

ABOUT THE AUTHORSxv

REVIEWERSxvii

ACKNOWLEDGMENTSxviii

CHAPTER 1

INTRODUCTION TO LASERS ANDLIGHT THERAPY

1

Key Terms1Learning Objectives1Introduction2History of Light and Energy Devices2Physics3Laser Tissue Effects17Intense Pulsed Light23Radiofrequency Devices23Light Emitting Diodes (LED devices)25Conclusion25Top 10 Tips to Take to the Clinic26

v

Chapter Review Questions26Chapter References27

CHAPTER 2

ANATOMY AND PHYSIOLOGY OF THE SKIN31Key Terms31Learning Objectives31Introduction32The Layers of the Skin34Aging Skin41Conclusion46Top 10 Tips to Take to the Clinic46Chapter Review Questions47Chapter References47

CHAPTER 3

HEALING THE SKIN FROM LASER INJURY51Key Terms51Learning Objectives51Introduction52The Insult53Types of Wounds56Wound Healing Compromised59Normal Scarring61Abnormal Scarring62Conclusion65Top 10 Tips to Take to the Clinic65Chapter Review Questions65

vi CONTENT S

Chapter References66Bibliography68

CHAPTER 4

LASER, LIGHT, AND RADIOFREQUENCYDEVICES

73

Key Terms73Learning Objectives73Introduction74Cooling Devices Technology74Vascular and Pigmented Lesion Devices76Leg Vein Devices83Facial Rejuvenation Devices87Hair Removal Devices99Tattoo Removal Devices105Skin Tightening Devices108Body Contouring/Lipolysis113Light Emitting Diodes (LED)116Acne Devices117Future Devices122Conclusion122Top 10 Tips to Take to the Clinic122Chapter Review Questions123Chapter References124

CHAPTER 5

CONSULTATIONS133Key Terms133Learning Objectives133

CONTENT S vii

Introduction134Types of Communication135Listening139The Office Consultation141Client Expectations147Conclusion149Top 10 Tips to Take to the Clinic150Chapter Review Questions150Chapter References150

CHAPTER 6

SKIN TYPING AND LASER TREATMENTS151Key Terms151Learning Objectives151Introduction152Fitzpatrick Skin Typing152SB OBAGI Skin Classification162Skin Type and Laser Treatments164Conclusion164Top 10 Tips to Take to the Clinic165Chapter Review Questions165Chapter References165Bibliography166

CHAPTER 7

FUNDAMENTALS OF SKIN CARE167Key Terms167Learning Objectives167

viii CONTENT S

Introduction168Using Cosmeceuticals with Light andLaser Treatments

168

Cleansers169Alpha Hydroxy Acids172Vitamin C173Moisturizers174Sunscreen175Hydroquinone178Retinoids179Conclusion180Top 10 Tips to Take to the Clinic180Chapter Review Questions181Chapter References181

CHAPTER 8

PRE-TREATMENT FOR LASERS ANDLIGHT THERAPY

183

Key Terms183Learning Objectives183Introduction184The Complete Therapeutic Program184Conclusion190Top 10 Tips to Take to the Clinic190Chapter Review Questions191Chapter References192Bibliography192

CONTENT S ix

CHAPTER 9

INDICATIONS AND CONTRAINDICATIONSFOR LASER AND LIGHT THERAPY

195

Key Terms195Learning Objectives195Introduction196Indications for Laser and Light Therapies196Combining Laser Treatments with Injectable Treatments202Contraindications for Laser and Light Therapies203Conclusion211Top 10 Tips to Take to the Clinic211Chapter Review Questions212Chapter References212

CHAPTER 10

LASER, LIGHT, AND RADIOFREQUENCYTREATMENTS

215

Key Terms215Learning Objectives215Introduction216Laser/Light Hair Removal216IPL Facial Rejuvenation232Photodynamic Therapy240Skin Tightening Procedures246LED Procedures251Conclusion253Top 10 Tips to Take to the Clinic253Chapter Review Questions254Chapter References254

x CONTENT S

CHAPTER 11

LASER AND LIGHT THERAPY SAFETY259Key Terms259Learning Objectives259Introduction260National Safety Agencies260State Licensure/Regulations264Professional Medical Organizations265Safety266IPL, Light, and Radiofrequency Device Safety286Conclusion286Top 10 Tips to Take to the Clinic286Chapter Review Questions287Chapter References287

CHAPTER 12

THE BUSINESS OF LASER AND LIGHTTHERAPY

291

Key Terms291Learning Objectives291Introduction292Buying a Laser or Light Device292Starting a Laser or Light Business296Business Plan for Independent Ownership301Medical Franchise305Selling Light and Laser Treatments306Conclusion310Top 10 Tips to Take to the Clinic310

CONTENT S xi

Chapter Review Questions311Chapter References312

APPENDIX A313

APPENDIX B317

APPENDIX C319

GLOSSARY321

INDEX333

xii CONTENT S

Preface

Each day we are blasted with information about lasers and lights for themedical spa, day spa, and medical office. But how do you decipher theinformation—how do you know which laser or light is right for your sit-uation? As the director of a medical spa, I have spent a good deal of timelooking at and buying equipment. Once the equipment is in our office,safety for client and the clinician is of utmost importance. But how doesone gain all of this knowledge and find out who is reputable withoutbeing biased? While a good business manager weighs all of his or herchoices, the decisions are wrought with the peril, burdened with the riskand potential expense of a bad decision.

This book is intended for those who are studying lights, lasers, andradiofrequency. It is a suitable text for the nurse, aesthetician, and busi-ness manager alike, with dedicated chapters to subject matter that is rele-vant to specific skill sets. That said, this text is written to expand on basicknowledge and take it from a conceptual level to a practical level.

We have researched and written this book so that we could satisfythat hunger for knowledge and information that is so important in thisnew high-technology area. Lasers and lights are developing into someof the most popular procedures in the skin-care industry. In fact, somewould say that skin care has gone hi-tech. From Fraxel™ treatments toLED, the spa—regardless of its specialty—is not complete unless sometype of laser and light services are offered. Lasers and lights can provideextraordinary results for qualified candidates.

This book takes modern research, facts, and opinions and shapesthem into a start-to-finish business model. This model has one funda-mental intent: ideal results for the clinician and the patient alike.

The chapters are organized, one on top of the other, with essential,must-have information on lights, lasers, and radiofrequency. To thiseffect, general knowledge is expanded upon, and insightful hints andrecommendations allow you to optimize your knowledge and achieveoptimal, replicable results to ensure your success. Each chapter has

xiii

questions and “Top 10 Tips to Take to the Clinic,” which will help youmove well beyond your training and give you knowledge that is helpfulwell beyond the classroom.

Lasers, lights, and radiofrequency are the wave of the future. Thisbook will help you to ride the wave and create treatments that your clientswill not only enjoy but also benefit from. It is a must-have book to add toyour library.

xiv P R E FACE

About the Authors

Pamela Hill received her nursing diploma from Presbyterian Hospitaland ColoradoWomen’s College, Denver, CO, and has practiced as a reg-istered nurse for more than 20 years. Her background includes 15 years ofoperational and leadership experience in the medical spa, medical skincare, and educational sectors. Ms. Hill has been instrumental in thegrowth and development of Facial Aesthetics, Inc. (FAI), a successfulColorado-based medical spa. An astute results-oriented leader with aproven track record of building and growing companies in the medicalappearance sector, she has been actively involved in the evolution of themedical spa model as well as research and development of the Pamela HillSkin Care product line. Ms. Hill has been active with patient care, thedevelopment of policy and procedure, and clinician education. Passionateabout the education of aestheticians in the medical spa settings, Ms. Hillbegan a relationship with Milady, an imprint of Cengage Delmar Learn-ing, in 2003. This relationship launched Milady’s Aesthetician series, a14-book series dedicated to the education of medical aestheticians andmust-have information for on-the-job success.

Patti Owens is presently working with James Brazil, MD, dermatologist,at the Olympic Dermatology and Laser Clinic in Olympia, WA. She hasmanaged the laser/aesthetic and marketing program along with per-forming cosmetic and aesthetic laser procedures under Dr. Brazil’s direc-tion. Ms. Owens is also involved with coordination of medical trainingworkshops, preceptorships, and research on a national level. She has beena clinical investigator in the planning and initiation of various FDAstudies.

Ms. Owens established a consulting business, Northwest LaserAesthetic, in 1999. She has coordinated regional and national laser educa-tion workshops along with hospital- and office-based managementprograms. She has been the Nursing/Allied Health Chairperson ofASLMS and in 1999 received the organization’s Nurse Excellence

Pamela Hill, RN

Patti Owens, RN, MHA,CMLSO

xv

Award. She is presently a national consultant for a variety of laser compa-nies and national organizations including Rockwell Laser Industries(RLI), Dermatologic Nurses Association (DNA), Meeting Designs,LLC, and Lumenis Laser Company. She served on the ANSI Z136.3nursing subcommittee for the 2002 and 2007 revisions. She was recentlyelected to serve a three-year term as the nursing–allied health representa-tive to the board at ASLMS.

Patti Owens’s past employment includes laser manager at ProvidenceSt. Peter Hospital fromNovember 1985 toMarch 2000. Her responsibil-ities included program development and supervision of 13 laser systems,implementation of the laser perioperative role, development of an aes-thetic laser in-house and mobile program, and enforcement of safety pol-icies as the facility’s acting laser safety officer.

Patti Owens received her BSN from the University of Colorado in1976 and graduated with her masters degree in health administrationfrom Chapman University in 1996.

xvi ABOUT THE AUTHORS

Reviewers

The authors and publisher thank the following individuals who havereviewed this text and offered invaluable feedback. This very importanttask, although time-consuming, is a critical component to the success ofany book. We are grateful for your time and your honest comments.

Steven Bengelsdorf, MD, FACS, The Franklin Center for Skin &Laser Surgery,

Franklin, TNAmy Fields Rumley, Greensboro, NCAustine Mah, President, Austine Inc. and Managing Editor,

PCI Journal, Plano, TXIrene Koufalis, European Body Concepts, East Texas, PAAda Polla Tray, MBA, President, Alchimie Forever,

LLC, Arlington, VA

xvii

Acknowledgments

PAMELA HILL, RN

When I accepted the opportunity to create a medical aesthetic series, myhusband wondered if I had lost my mind. He worried that I would havetime for little else but sitting in front of my computer—and he was right.This is the thirteenth book in the Aesthetician series. My husbanddoesn’t ask anymore—he knows I am working on a book. As it shouldbe, my first thanks go to my husband. Always at my side, he has beenmy best critic, my beacon of light, my teacher, and my best friend with-out whom this book would not exist.

Next, a special thank you goes to Patti Owens. A bright and talentedlady, Patti met the challenge of writing this book with me head-on. Sheput aside personal obligations while writing this book. I will always begrateful for her help.

Additional thanks go to those at Milady who believed in my messageand supported me through this process.

PATTI OWENS, RN, MHA, CMLSO

I would like to thank my husband. Without his patience, endearing sup-port, and editing skills, this book would not have been a reality. My hus-band and our four children are the motivating factor in my life. I wouldalso like to thank Dr. James Brazil as my employer, mentor, and friendat Olympic Dermatology and Laser Clinic. I have thoroughly enjoyedthe educational opportunities for the past eight years as the manager andcoordinator of the laser/cosmetic program. Penney Smalley, RN;Lumenis LTD; and Rockwell Laser Industries have also been instru-mental in my consulting opportunities and have contributed to my teach-ing style and expertise.

xviii

Most of all, I would like to thank Pamela Hill for this opportunity tojoin her as a co-author in this exciting endeavor. It is my hope that thisbook will provide the foundation for aestheticians and other cliniciansto become the most astute, highly skilled, and safe practitioners workingwith laser and light technologies.

ACKNOWLEDGMENT S xix

Introduction to Lasersand Light Therapy

KEY TERMS

ablationabsorptionabsorption coefficientactive mediumbipolar radiofrequency

energychromophoredelivery systemdispersing electrodeElectromagnetic

Spectrum of Radiationfluence (radiant energy)impedanceindication or applicationinfraredIntense Pulsed Light (IPL)

irradiancejouleslaserLEDmasermelaninmicronmodulatemonochromaticmonopolarnanometeroptical resonator cavityoxyhemoglobinphotochemical or

photodynamic therapyphotomodulation

photonspolychromaticpower densitypulse durationpulse widthselective photothermolysisspot sizeTEM modethermal relaxation time

(TRT)ultravioletwattwavelength

LEARNING OBJECTIVES

After completing this chapter you should be able to:

1. Describe how laser light is created.

2. Differentiate between stimulated emission and spontaneousemission of radiation.

3. Describe the four properties of laser light.

4. Review the four characteristics of laser light.

5. List the three major chromophores in the skin.

6. Describe an Intense Pulsed Light system.

7. Review the differences between bipolar and monopolarradiofrequency energy.

CHAPT E R 11

1

INTRODUCTION

Procedures for rejuvenation of the face and body are activelypursued by the public at a staggering rate. According to theAmerican Society for Plastic Surgery (ASPS) cosmetic proce-

dures have risen to 11.8 million. That is a 446 percent increase between1997 and 2005 and a 7 percent increase over 2006.1 As a practitioner per-forming these procedures, one needs to have a comprehensive under-standing of the physics, tissue interactions, delivery systems, andmultitudes of devices commonly used in today’s cosmetic market. It willbe mandatory that you master your device’s operations along with specif-ic parameters per indication or application to produce safe, effective,and reproducible outcomes for your client.

HISTORY OF LIGHT ANDENERGY DEVICES

As youmay already know, the history of medical light sources began withAlbert Einstein in 1917, the same time most modern physics theoriesoriginated. It was at this time that Einstein published his paper “ZurQuanten Theorie der Strahlung” (“To the Quantum Theory of theRadiation”) outlining the theory of laser light in the German journalPhysikalische Zeit.2 He was able to mathematically describe the emissionof spontaneous sunlight and theorize how a brilliant form of lightenergy could be artificially created. However, it wasn’t until 1958 thatTheodore Townes and Arthur Schawlow published the first theoreticalcalculations for a visible light source at Bell Laboratories. The maser(microwave amplification by the stimulated emission of radiation) wasinitially created as the first type of invisible light using ammonia gas andmicrowave radiation. In May 1960, Theodore Maiman of the HughesAircraft Research Laboratories created the first laser at the 694 nano-meter (nm) red spectrum of light from a ruby crystal. This first pure formof light revolutionized the medical field in the areas of dermatology andophthalmology.

Lasers quickly moved from the research domain into the physi-cian’s hands. The neodymium-doped glass laser was created in 1961.(See Figure 1–1.) In 1962, the argon laser, which used two visible wave-lengths of blue-green light, was created for ophthalmologists to use inthe treatment of retinal disorders. The first neodymium-doped yttrium-aluminum garnet (Nd:YAG) laser was developed in 1964 for experimen-tal removal of tattoos and vascular lesions. In 1965, the first carbon

Indications orapplicationAny sign or circumstance indicating that

a particular treatment is appropriate or

warranted.

MaserMicrowave Amplification by Stimulated

Emission of Radiation.

2 CHAPT E R 1

dioxide CO2 laser was created from CO2 gas. T. Polanyi developed anarticulating metal arm with aligned mirrors to direct the CO2 laser to dis-tant anatomical areas.3 Subsequently, an ear, nose, and throat (ENT)surgeon named Dr. Geza Jako used this device to treat vocal cord lesionswith the assistance of a microscope. From this time on, laser research anddevelopment ignited the technological explosion of devices that we expe-rience today. There are presently more than 150 different types of laserlight and energy devices sold in today’s cosmetic market.

PHYSICS

In learning about lasers, light sources, and radiofrequency devices, thefirst requirement is to grasp the basic technical background and terminol-ogy needed to understand today’s cosmetic field. Numerous questionsmay arise when first delving into this complicated arena. What causes alaser light to be created? What bio-tissue effects occur? What is a wave-length of light? Why can’t you use one device to treat all your client’sconcerns? What are the advantages of these laser/light devices comparedto conventional equipment?What is the difference between a laser and anIntense Pulsed Light (IPL) versus an LED device? The intent of thischapter is to lay the foundation for understanding the science and art ofcosmetic laser and light source treatments.

Figure 1–1 An early Nd:YAG laser system. Courtesy ofTechnology Concepts International - Penny Smalley RN.

I N T RODUCT ION TO LASE R S AND L IGHT THE RAPY 3

Electromagnetic Spectrum of Radiation

To learn about how laser light is created, one needs to start with the basicsof physics. Laser light is in essence a high-powered flashlight that hasbeen efficiently harnessed to provide a narrow, directional beam of light.The sun emits rays of light that are composed of a multitude of invisibleand visible forms of energy. This light can be broken down into invisibleultraviolet energy, invisible infrared light, and visible light. As the sun-light passes through the atmosphere, ultraviolet light is absorbed primar-ily by the ozone layer in the upper atmosphere. The invisible infraredenergy is generally absorbed by water and carbon dioxide molecules inthe atmosphere, and the visible light penetrates down to the earth surface.TheElectromagnetic Spectrum of Radiation is made up of all of theseforms of energy whose spectrum extends from long radio waves to ultra-short gamma. (See Figure 1–2.) The emissions that make up this spec-trum travel at the speed of light.

The type of energy in the electromagnetic spectrum of radiation iscomposed of discrete particles called photons. Photons travel at thespeed of light in the form of a wave at 186,000 miles per second.4 Eachtype of energy, whether it is visible or invisible, generates a particularwaveform. Awavelength refers to the physical distance between the top(amplitude) of one wave to the top of the next wave. (See Figure 1–3.)Each wavelength of light energy that is generated is measured in unitsof length called nanometers and micrometers. A nanometer (nm) is

Figure 1–2 The Electromagnetic Spectrum of Radiation. Courtesy ofTechnology Concepts International - Penny Smalley RN.

UltravioletRadiation that we cannot see; part of the

electromagnetic spectrum.

InfraredInvisible light.

ElectromagneticSpectrum of RadiationMade up of all of forms of energy whose

spectrum extends from long radio waves

to ultrashort gamma.

PhotonsMiniscule units of electromagnetic

radiation or light.

WavelengthThe distance between two consecutive

peaks or troughs in a wave.

NanometerOne billionth of a meter, or 10

-9.

4 CHAPT E R 1

a billionth of a meter, or 10−9. A micrometer (or micron; [mm]) is amillionth of a meter, or 10−6. One needs to be aware of the metric systemwhen working with lasers, for a laser’s light is designated by its wave-length, which can be referred to either in nanometer or micrometer mea-surement. For example, Nd:YAG’s wavelength is labeled either 1064 nmor 1.06 mm.

The human eye responds primarily to energy wavelengths between400 nm and 750 nm. The energy in this range is visible radiation, whichwe can simply call “light.”5 The colors run from one to the next as seenwith the particular color properties of the rainbow’s spectrum of light. Forexample: 488 nm is blue, 532 nm is green, 577 nm is yellow, 590 nm isorange, and 694 nm is deep red. (See Figure 1–4.) However, the majorityof the lasers used in the esthetic field are invisible to the eye and fall in theinfrared spectrum of light. Cosmetic infrared lasers can be classified aseither near-infrared (700 nm to 1200 nm) or mid-infrared (1200 nm to3000 nm) wavelengths of light. Even though they are invisible, they arestill safe and very therapeutic in the cosmetic industry.

Around 9 percent of the energy from the sun is in the form of ultravi-olet wavelengths (180 nm to 400 nm).6 Ultraviolet radiation can haveenough energy per photon to cause molecules to become ionized and emitparticles.7 The ionization of these particles can be considered hazardous to

Wavelength

Short wavelengthHigh frequencyHigh intensity

Efficient for light skin

Long wavelengthLow frequencyLow intensity

Mild for dark skinA

mpl

itude

Figure1–3 A wavelength is the measurement between the distance oftwo peaks in a wave.

MicronA millionth of a meter, or 10

-6.

Did You Know?A wavelength’s characteristics

are specific to the type of laser

light source used. For example, a

diode laser used for hair removal

has a wavelength of 800 nm and

penetrates only 2–3 millimeters

(mm), whereas an Nd:YAG laser

has a wavelength of 1064 nm

and penetrates 3–5 mm deep.


human beings. Potential risks are associated with intense exposure toultraviolet light as seen in DNA cellular damage, mutations, and possiblecancer. These types of energy are not commonly used in the esthetic clinicand most often are seen in the forms of X-ray and nuclear ultraviolet radi-ation. Many of your clients may ask if exposure to laser light will be harm-ful or have the potential to cause cancer. You can reassure your clients byrelating that, at the present time, there are no known anecdotal or pub-lished articles linking cancer diagnosis to cosmetic laser treatments. Arecently published study by H. Chan, MD, in which 50 treatments onmice were performed over 6 months with different types of lasers andIntense Pulsed Light systems, found no evidence of skin cancers or skintoxicity.8 The types of laser and light sources to be used in your estheticpractice fall into the safe areas of the Electromagnetic Spectrum of Radia-tion, with no known short-term or long-term exposure hazards.

Creation of Laser Light

The Bohr atomic model provides the basic theory of laser energy. A pos-itively charged nucleus consists of protons and neutrons, with negativelycharged electrons circulating in an orbit. In their resting state, electronsare at their lowest energy level.9When an intense energy source is appliedto a molecule, the energy is absorbed for a fraction of a second andorbiting electrons move to a higher, excited orbit. As the electronsdescend back down to the ground level, this energy is released as a photonwith a particular wavelength on the Electromagnetic Spectrum of Radia-tion. This reaction is called spontaneous emission of light and occurs nat-urally, as seen with sunlight. (See Figure 1–5A.)

microwavesTV andradio

waves

x-rayscosmic

rays

KTPCO2

Ruby Nd:YAG

Er:YAG

Diode Holmium

Excimer

SampleLaserTypes

UV

VISIBLE INFRARED

Argon

400 nm 700 nm

Dye

190−

390

nm

488−

514

nm

577−

630

nm

694

nm

532

nm

800

nm

1064

nm

2100

nm

2940

nm

1060

0 nm

Figure1–4 The visible and invisible portions of the electromagneticspectrum of radiation with the most common lasers identified.

6 CHAPT E R 1

The word laser is really an acronym that stands for “light amplifica-tion by the stimulated emission of radiation”. Einstein proposed the the-ory of stimulated emission of light, which stated that, in an excited state,a photon of energy would be produced, in the presence of other identicalphotons. He also proposed that two identical photons would travel in thesame direction.10 Stimulated emission occurs when an already-excitedelectron absorbs a newly created photon of equal energy. Upon des-cending back to its resting state, two identical photons are now released.(See Figure 1–5B.) This formation of a laser beam occurs inside the tubeor head of your laser. Turning on your laser machine will produce intenseenergy by either creating high-voltage electricity or stimulating a high-intensity light source, like a krypton arch lamp. Electrons become stimu-lated by this intense energy and spontaneously create identical photons asthey collide with mirrors placed on opposite ends of the laser tube. Thesemirrors reflect the emitted photons back and forth between the mirrors.Two photons collide with two more photons, resulting in four photons,and a chain reaction occurs. Each time they pass back through the medi-um, more photons are created, until a population inversion occurs. Pop-ulation inversion is defined as state where more than 50 percent of thephotons emitted are identical to each other.11

In general, laser systems consist of six basic components: the activemedium, the laser tube or resonator, the power supply, the cooling sys-tem, the software and microprocessor, and the delivery system. Withinevery laser device, there is a laser tube or optical resonator cavity. Theoptical resonator can be constructed in numerous ways. Some consumemore than a third of the device’s size, and others are so small that they fitinside the handpiece. Universally, the optical resonator is constructed

A. Spontaneous Emission

Photon

Photons

Electron

B. Stimulated Emission

Figure 1–5 Spontaneous emission showing excited electrons releasingrandom wavelength photons as they fall back to their resting state.Stimulated emission showing electrons releasing two identical photons,one recently absorbed and the other from the excitation phase. Courtesyof Lumenis® Ltd.

LaserA device that emits radiant energy at

variant frequencies for therapeutic

purposes.

Optical resonatorcavityThe part of the laser that contains the

active medium.


with mirrors positioned on opposite ends inside a sealed glass tube or ametal reflective cavity. (See Figure 1–6.)

The optical resonator contains some type of active medium, gas,liquid, or solid, that is stimulated to create the laser light. Common gasmedium lasers can contain common argon, carbon dioxide, or helium-neon gas particles. Liquid medium laser tubes have organic liquid or dye.A crystal medium is usually a synthetic, manufactured crystal of yttrium-aluminum garnet (YAG) particles that are doped with certain elementssuch as holmium, neodymium, and thulium, or erbium electrons. Dif-ferent types of laser systems are named in reference to their activatedmedium. Diode lasers are solid-state devices manufactured out of semi-conductor crystals or diode arrays. Diode lasers emit light when an elec-trical current is passed through a very small semiconductor chip withmicro-mirrors positioned directly onto each end.12 These devices tendto be smaller, lighter, more economical, and more durable due to the sim-plicity and stability of the components.

Most power supplies require a single-phase 110 or 220 Value AntiCheat (VAC) outlet. It is important to check the electrical requirementsprior to installation of your laser or light source. The voltage that is gen-erated inside a laser system is intense enough to cause electrocution if anuntrained individual attempts repairs. Most medical laser products havewater or air cooling systems that remove the generated heat from the unit.

Energy Source(e.g. flashlamp, electric current, laser)

Pumping Cavity

Partially ReflectiveMirrorR-90%

Laser Medium(e.g. crystal, gas, dye)

ReflectiveMirror

R-100%

Laser Light Target Tissue

Figure 1–6 The optical resonator or laser tube inside a laser system.Two mirrors are positioned on either side of the laser medium; one is100 percent reflective and the other is about 90 percent reflective. Whenthe hand switch or foot pedal is depressed, light exits the laser headand is directed to the tissue.

Active mediumThe part of a laser that absorbs and

stores energy.

8 CHAPT E R 1

Microprocessors and software programs execute the internal operationsof the device, create the laser energy, store data, and monitor the system’sstatus and performance. A laser’s delivery system is the physical hard-ware needed to transfer the energy from the head of the laser to the treat-ment site.13 Delivery systems vary from emission of light through hollowmetal articulating arms, silica glass fibers, handpieces, optical scanners,and endoscopes.

Characteristic of Laser Light

Laser light possesses unique intrinsic characteristics that differentiateit from normal white light. Normal light from a lightbulb generates apolychromatic or multiple-wavelength array of light. When this lightis projected through a prism, one sees the multitude of visible wave-lengths in the colors of a rainbow. (See Figure 1–7A.) If the intensity isplotted per wavelength, one sees a bell curve with predominance in theyellow to orange spectrum of visible light.14 This white light is diffusein nature and can quickly disperse in space within a very short distance.Laser light is different, which makes it easily harnessed for esthetic treat-ments. If a visible laser light, such as a red 640 nm wavelength, is passedthrough a prism, one would see exiting only a distinct red beam. (SeeFigure 1–7B.) If the intensity versus the wavelength is plotted, very highintensities at a single red color would be observed. This light is brilliant innature and can travel over long distances with little to no divergence.What are the characteristics that dictate this response?

A. Polychromatic B. Monochromatic

Figure 1–7 Natural light versus laser light.

Delivery systemThe physical hardware needed to transfer

the energy from the head of the laser to

the treatment site.

PolychromaticConsisting of light of multiple

wavelengths, appearing as different

colors.


Coherent EnergyNormal light from a lightbulb can be viewed as a multitude of frequen-cies, all out of phase with each other, all traveling in different directions.Laser light is considered coherent because the laser photons travelthrough space both temporally and spatially. Each wavelength of lightis composed of photons that are traveling in both time and space as asingle unit of energy. (See Figure 1–8.) This degree of precision and theability to manipulate the light make lasers unique compared to otherforms of technology.

Monochromatic EnergyA flashlight contains all the visible colored wavelengths of light, and thecombination of frequencies emits white light. Laser light differs becauseit ismonochromatic. That is, it is composed of one wavelength and onecolor, whether visible or invisible. (See Figure 1–7B.) The type of mole-cule that is stimulated determines which wavelength of laser light willbe emitted. Each specific wavelength of light affects the depth of penetra-tion and tissue reaction, and it creates a unique clinical effect.

Collimated EnergyCollimation refers to the non-divergent properties of laser light. Photonsfrom a flashlight or light bulb are composed of multiple wavelengths ofvisible light. The light quickly disperses over time and space. However,laser photons are parallel to each other and the diameter of the beam hasonly minimal divergence. This property allows the laser light to remainin phase for extended distances. The collimated nature of laser energy

Laser Light Photons(Coherent)

Natural Light Photons

(Incoherent)

Figure 1–8 Coherent laser light versus incoherent natural light. Courtesyof Technology Concepts International - Penny Smalley RN.

MonochromaticLight of one wavelength, which therefore

appears as one color.

10 CHAPT E R 1

is essential to harness the beam to produce a focused spot by using a lens.This high-powered, focused beam is required for many surgical andesthetic procedures. (See Figure 1–9.) Laser light is used diverselythroughout the aerospace, military, engineering, entertainment, andmedical fields due to this unique property.

High Optical EnergyThe last characteristic of laser light is its ability to reach high peak energiesfor cutting, coagulating, ablating, and/or vaporizing tissue. Optical ener-gy is determined by the laser’s power, the spot size, and the pulse durationor pulse width. Laser light energy refers to the ability to do the work. Acommon unit of energy that is used with lasers in the esthetic field isjoules. Joules is the term that describes the amount of energy deliveredto tissue multiplied by the time it takes to deliver it. Fluence, or radiantenergy, refers to the energy of the pulsed laser beam—it is expressedin joules per cm2 ( J/cm2).15 (See Figure 1–10.) Most esthetic lasers arepulsed to minimize thermal damage while destroying the target medium.One may also note the machine’s energy display output expressed inmillijoules (mJ), or 1/1000 of a joule. Therefore, .82 J or 820mJ both referto the same power output delivered to the treatment site.

A. B. C.

Figure 1–9 A lens can be used to adjust the intensity of the laserbeam so that it can be used as (A) a cutting device, (B) a coagulatingdevice, or (C) a heating device.

JoulesUnits of energy or work.

Radiant energy orFluenceThe energy level of a laser; measured in

joules.


Power is the rate of doing the work, and a unit of power is referredto as a watt. Power density is the rate of energy that is being deliv-ered to tissue by a laser light source and is a common unit of measure-ment with continuous wave lasers. With continuous wave lasers, a laserbeam can be constantly fired on the tissue. Power density is a parameterthat describes how powerful the laser beam is at the surface of the skin.Irradiance, or power density, is measured in watts per centimetersquared (W/cm2).16

Pulse duration (or pulse width), which is measured in nano-seconds, microseconds, or milliseconds, is the timing of light energy, orhow long the laser is actually emitted on the skin. The longer the laserstays on the tissue, the deeper the penetration and the more thermaleffects are produced. Some lasers are emitted in a continuous wave modein which the energy is fired the entire time one’s foot is on a foot pedal.Other laser systems can deliver energies of light in individual pulses. Thesuperpulse and ultrapulse CO2 laser was designed to emit high-poweredpeaks of energy with cooling time in between to reduce thermal damage.However, most esthetic lasers are pulsed in a millisecond or microsecondtrain. Q-switched (nanosecond) pulse duration is used commonly toproduce incredibly high-peaked powers, producing a photoacousticshock-wave effect to tissues.17 At 35 megawatts, the intense power of theQ-switched laser can cause a mechanical disruption or breakdown of thetargeted object.

Figure 1–10 Laser machine showing fluence in J/cm2.

WattThe unit of power produced by a current

of 1 ampere acting across a potential

difference of 1 volt.

Power densityThe rate of energy that is being delivered

to tissue by a laser light source; a

common unit of measurement with

continuous lasers (W/cm2).

IrradiancePower density, measured in watts per

centimeter squared (W/cm2).

Pulse durationThe duration of an individual pulse of

laser light; usually measured in

milliseconds. Also known as pulse width.

Pulse widthSee pulse duration.

12 CHAPT E R 1

Spot size is also necessary to reach high optical energy. It is a mea-surement of the diameter of the beam that is in contact with the tissue.(See Figure 1–11.) In changing the laser’s focusing lens, the spot size willdecrease or increase in diameter. The larger the laser beam’s spot size, theless fluence is affecting the tissue. By reducing the spot size by half, oneincreases the power density or fluence by a factor of four. Spot size in theaesthetic field is usually measured in millimeters.18

The quality of the beam’s spot size as it comes in contact with the tis-sue can also be measured. Beam quality represents the distribution of thelaser energy across the beam diameter. TEM mode is common termi-nology that indicates how focused the beam is. This measurement canbe represented in a bell-shaped curve. The fundamental TEM00 moderepresents the most powerful, smallest, and most focused beam that isgenerated, which retains its shape whether it is in focus or out of focus.19

The CO2 laser produces a TEM00 Gaussian beam, which is a superiorcutting laser due to the high power densities produced by the mode.Mostesthetic lasers, however, possess a top hat beam profile that represents anequal distribution of energy across the entire spot size. (See Figure 1–12.)Therefore, every time you turn on a laser device, you will affect the entiretarget with each pulse and not produce a hot spot or unequal energyoutputs.

Articulated Arm

Mirrors

Mirrors

FocusingLens

TargetSite

Figure 1–11 Illustration of spot size.

Spot sizeThe width of a laser beam.

TEM modeCommon terminology that indicates the

quality of the beam or the beam profile.


Laser Properties

Laser radiation or light must be converted into different forms of energyto produce therapeutic clinical outcomes. The distinctive properties oflaser light can cause four different light–tissue effects.

AbsorptionAbsorption is the physical process in which light energy is converted bythe targeted tissue into either heat, an acoustic response, a chemical reac-tion, or cellular stimulation.20 (See Figure 1–13A.) The absorption orattraction of a particular wavelength of light toward a specific targetcontrols the theory behind laser tissue interactions. When a specificwavelength of light penetrates tissue, the absorption process actuallyremoves a certain amount of energy per unit of tissue.21 The laser lightcan be absorbed by the skin’s epidermal surface or by material in thetissue called a chromophore. A chromophore is the target in the epider-mis or dermis that absorbs the laser beam’s thermal energy, causing thedesired ablation or destruction of the material. Common chromophoresin the body are water, hemoglobin in blood, collagen, and melanin.Particular wavelengths are absorbed by particular chromophores.Hemoglobin tends to have multiple absorption peaks in the visiblegreen–yellow spectrum of light, whereas with melanin, absorption grad-ually decreases the longer the wavelengths are. (See Figure 1–14.) Thebeauty of esthetic laser systems is that one can manipulate the wave-length, energy output, and treatment parameters so that a specificchromophore can be selectively destroyed while other chromophores are

Gaussian beam profileMiddle of beam is the point of highest energy

Top hat beam profileEnergy is evenly distributed

across the beam

Non-AblativeEsthetic Devices

AblativeEsthetic Devices

Figure 1–12 The TEM modes of a laser’s beam profile.

AbsorptionThe uptake of one substance into another.

ChromophoreChemical that presents with color when

properly prepared; elements that laser

light is attracted to: blood, pigment, hair

color.

AblationRemoval of surface material from a body;

usually associated with the presence of a

wound.

Did You Know?The absorption spectrum of light

illustrates how hemoglobin,

melanin, and water are absorbed

at different wavelengths of light.

14 CHAPT E R 1

C. Transmission

B. Reflection

Laser

D. Scattering

A. Absorption

Skin

Skin

Skin

Laser

Laser Laser

Mirror

Figure 1–13 The four universal properties of laser light.

10,000

1,000

100

10

1.0

0.1

0.01

0.001

200 nm 1000 nm 2940 nm

InvisibleInfrared

10,600 nm 20,000 nm

CO2Laser

Wavelength measured in nanometers

InvisibleUltraviolet

Visible

Er: YAGLaser

WaterHemoglobin

Melanin

Lo

w t

o H

igh

Ab

sorp

tio

n

Figure 1–14 The absorption curve of hemoglobin, melanin, and waterto each wavelength of light.


not. This is why there are so many different lasers, each with a differentpurpose. (See Figure 1–15.)

ReflectionAbout 4 to 6 percent of natural light is reflected at the level of the stratumcorneum in the epidermis.22 A laser beam can also reflect off the skinor any shiny surface such as a mirror, jewelry, or instrumentation. (SeeFigure 1–13B.) The flatter or smoother the surface, the more intensethe reflection would be. Once reflected, the thermal properties of thelaser light could possibly cause a surface skin burn, fire, or even eye damage.

TransmissionThe amount of transmission depends on the wavelength of the light.Shorter wavelengths (300 to 400 nm) have very superficial penetrationof less than 0.1 mm into the epidermis. Visible light lasers and somewavelengths in the near-infrared zones (400 nm to 1300 nm) can easilypass through the epidermis and dermis and can penetrate deeper due toless scattering. (See Figure 1–13C.) Some laser light can also be transmit-ted through clear fluids and even glass.23

ScatterScattering of laser light refers to the physical processes of the skin thatcause a beam to be deflected into some or all new directions. (See Figure1–13D.) Scattering reduces the laser light’s energy as the beam is trans-mitted forward, laterally, and even backward. Scattering is importantwith cosmetic laser systems because it rapidly reduces the therapeuticeffects on the tissue. In the skin, scattering is mostly due to the largecollagen molecules in the dermis. Scattering decreases with longer wave-lengths, making it ideal for targeting deep dermal vessels and hair

• Hair removal lasers are absorbed by dark pigment, or melanin.• Vascular lasers seek out blood or oxyhemoglobin as theirchromophore.

• Lasers that produce new collagen and rejuvenation tend to bewater or collagen absorbers.

• Lasers used for clearance of pigmented lesions or lentigos targetmelanin in the epidermis and dermis.

• Tattoo lasers target specific dyes or tattoo pigment.

Figure 1–15 Different cosmetic lasers are absorbed by differentchromophores.

MelaninPigment of the skin, hair, and eyes;

protects skin from ultraviolet damage.

OxyhemoglobinOxygenated blood.

16 CHAPT E R 1

follicles. However, with some laser energies such as the Nd:YAG laser,tissue penetration can cause deep thermal destruction at greater depthsbut also can backscatter toward the client’s and operator’s eyes.24 Thegreater the degree of backscatter, the higher the risk of optical injury.

Selective Photothermolysis

Selective photothermolysis governs today’s esthetic laser and lightpractice. The theory of selective photothermolysis was published byR. Anderson, MD, and J. Parrish in 1983 to elegantly describe the selec-tive absorption of a specific light by a targeted chromophore.25 This light(photo), delivers thermal energy that is engineered to cause selectivedestruction, or lysis, of the designated target. Selective photothermolysisrefers to the use of a selected wavelength of laser light coupled with theaccurate pulse duration and energy settings to limit the destruction with-in the chromophore of the treated area. In essence, what one is trying toachieve is targeted destruction of a blood vessel, hair follicle, or age spotwith minimal heating or side effects to the surrounding healthy skin.

To achieve selective photothermolysis, one needs to be aware of thethermal relaxation time (TRT) of the target. TRT is the amount oftime necessary for a chromophore to lose 50 percent of the heat by diffu-sion.26 By limiting the exposure of the laser light to a time shorter thanthe thermal relaxation time (TRT), the energy is contained in the select-ed target and does not produce collateral damage to the surroundingtissue. Thermal relaxation time varies based on the size and density of thetarget. The larger the object, the longer the TRT. Subsequently, TRT ofchromophores will vary, with very small tattoo particles having a TRT of2 to 3 nanoseconds versus larger leg veins with a TRT of 300 milliseconds.Therefore, a large target requires a longer laser pulse duration. Larger tar-gets slowly absorb the heat, become damaged, and then dissipate theremaining heat into the surrounding epidermis and dermis. The oppositeis also true—small objects with short TRT need shorter pulse durationsto quickly destroy the chromophore while sparing the epidermis. Thistheory is essential in producing the desired therapeutic response in yourtarget while protecting the epidermis and not causing undesirable sideeffects of blistering, hyper- or hypopigmentation, or scarring.

LASER TISSUE EFFECTS

A laser beam’s effect on tissue can produce a multitude of responsesdepending on the particular wavelength being used and the tissue thatis being treated. The best way to understand the cosmetic laser field is

SelectivephotothermolysisThe selective targeting of an area using a

specific wavelength to absorb light into

that target area sufficient to damage the

tissue of the target while allowing the

surrounding area to remain relatively

untouched.

Thermal relaxationtime (TRT)The amount of time it takes a substance

(e.g., dermal tissue), after heating, to

return to its normal temperature.

Did You Know?Used in pulsed lasers, energy

fluence is measured in joules

per square centimeter, ( J/cm2).

The pulse duration should be

longer than the thermal

relaxation time of the epidermal

tissue but shorter than the

thermal relaxation time of the

targeted chromophore.


to understand which lasers are used for which types of procedures andwhy. The biological interactions between tissue and laser energy deter-mine treatment outcomes and results.

The absorption spectra of the major skin chromophores dominate thelaser–tissue interactions.27 The absorption of light is described in Beer’sLaw, which states how a particular chromophore or medium absorbs aspecific wavelength of light. The absorption coefficient is a logarithmicmeasurement describing how a particular wavelength of light will beabsorbed and to what depth.28 The absorption coefficient depends on thepresence and amount of chromophores in the skin. As laser light is trans-mitted through tissues, it interacts with the chromophores in the skin.The absorption coefficient is determined by how deep the laser energywill penetrate before only 10 percent of the energy remains. Shorter wave-lengths in the visible light spectrum have a shorter absorption coefficient.For example, the KTP laser at 532 nm has a penetration depth of .9 mmbefore the energy is extinct. However, longer wavelengths like theNd:YAG laser at 1064 nm have a longer coefficient due to little scatter,and they can penetrate up to 4 mm deep.

Photothermal Tissue Reactions

With cosmetic procedures, most therapeutic effects are seen as cellularreactions to thermal laser energy. As the laser’s radiant energy comes incontact with tissue, the light is absorbed by its target chromophore andtransformed to heat. As a cell’s internal temperature reaches between50° C and 100° C, most related tissue undergoes irreversible damage andthe destruction of cellular proteins.29 In other words, when exposed tohigh energies, the intracellular content begins to boil and the cellularmem-brane ruptures, resulting in vaporization. Intracellular contents, denaturedproteins, particles of blood cells, viral and bacterial particles, and gases areemitted in the form of smoke or laser plume. (See Figure 1–16.) Whatremains is an area of necrotic tissue surrounded by a reversible damagedzone of tissue that will eventually repair itself. The CO2 and erbium lasersare classic examples of this type of ablative skin reaction which is used insurgical procedures and for facial laser resurfacing by dermatologists andplastic surgeons.

Vascular Lesions ResponseVascular lasers target blood vessels by using a pulse duration synchro-nized close to the TRT of oxyhemoglobin, the targeted chromophore inblood. Using the theory of selective photothermolysis, pulse durationsand fluence are modified to treat the different sizes of blood vessels. Larg-er vessels require longer pulse durations versus smaller capillaries, as seen

Absorption coefficientA logarithmic measurement describing

how a particular wavelength of light will

be absorbed and to what depth.

Did You Know?The longer the wavelength, the

deeper the penetration. That is

why the 532 nm wavelength is

more appropriate for superficial

facial vessels, and the 1064 nm

light is used primarily for deep

leg veins and more vascular

abnormalities.

18 CHAPT E R 1

in rosacea, that require shorter pulse durations. During a laser treatment,the laser energy coagulates the blood and the heat is transmitted to injurethe vessel wall. The desired clinical response is either darkening or coag-ulation of the vessel, vasospasm in which the vessel blanches and then candisappear, or vasoconstriction in which the vessel wall collapses. Smudg-ing or erythema of the vascular component of the treatment site is also adesired end point. Clearance of the vascular lesion is seen slowly over thenext three to six weeks as blood clots and wall debris are eliminated by themacrophages. If purpura or bruising is noted, then TRT has beenexceeded and has ruptured the vessel wall. One should readjust the pulsewidth or decrease the fluence to cause a more uniform heating of theblood and cell wall without rupture of the vessel.30 The most commonlasers used in the cosmetic field for treatment of vascular lesions rangefrom the 532 nm to 1064 nm wavelengths.

Pigmented Lesions ResponsePhotothermal non-ablative devices can also be used very successfully forthe treatment of pigmented lesions. When melanin is the chromophore,the absorption is the highest from the ultraviolet wavelengths into theinfrared spectrum at 1200 nm.31 Shorter visible wavelengths are moreeffective for more superficial epidermal lentigos, with longer wavelengthspenetrating deeper for treatment of dermal lesions, such as Nevus of Ota.Once the laser beam comes in contact with the targeted lesion, melaninabsorbs the light, which is then transformed to heat. The laser energybreaks the melanin up into small particles, and melanin-containing cells

Figure 1–16 Cell being vaporized with the CO2 laser andcontents being emitted into the air.

Caution:Whenever melanin containing

lesions are treated, the

aesthetician needs to be sure

that they are non-cancerous or

pre-cancerous lesions.


(melanocytes/keratinocytes) are damaged. The desired immediateresponse is noted to be either erythema due to an inflammatory responseor darkening of the lesion due to epidermal accumulation of the particles.The thermal absorption results in the destruction of the lesion with light-ening or denuding of the epidermis.32 Usually one will note a crusting ordarkening over the pigmented lesions, which fades within 7 to 14 days.Clearance is achieved with melanin particles and cellular debris beingeliminated by the immune system. The laser device one chooses will bedetermined by whether the pigment is dermal or epidermal in nature.The ability to determine this characteristic in the treatment of pigmentedlesions will dictate your client’s success or failure.

Collagen Stimulation ResponseIn the late 1980s and 1990s, ablative lasers such as the CO2 and erbiumlasers were created to improve mild to moderate rhytids, acne scarring,and sun-damaged skin. The primary focus was to artificially produce col-lagen stimulation and remodeling. Because the targeted chromophore iswater, these lasers were engineered to remove microns of tissue with min-imal adjacent thermal injury. During the vaporization of the epidermisand a portion of the dermis, thermal damage occurred to the underlyingtissue, which produced collagen contraction and skin tightening. Duringthe days and weeks that followed, re-epitheliazation originated from thehair follicles and other tissue to improve skin tone, skin texture, acne scar-ring, and facial wrinkles.33 The benefits, however, did not come withoutprolonged recovery periods and reported side effects of hypopigmentation,hyperpigmentation, scarring, and infection.

The current trend in esthetic procedures is to develop new technolo-gies that are non-ablative in nature but produce the benefit of ablativetechnologies. Non-ablative collagen remodeling has been associated withinfrared lasers that are selectively absorbed by water but penetrate deeplyinto the dermis (1320 nm, 1450 nm, 1540 nm). With these differentwavelengths, the intent is for dermal injury while preserving the epider-mis. Thermal injury to the dermis can result in fibroblast stimulation andthe production of new collagen. Non-ablative technologies are aimed attreating mild to moderate photoaged skin with results more conservativein nature than the ablative technologies. Recently, there has been anexplosion of new devices in the field of fractional resurfacing. Fractionaltechnology involves the delivery of pixel-size columns of thermal energythat can penetrate into the dermis. (See Figure 1–17.) Multiple treatmentsessions are usually required and result in erythema and edema that canlast for several days to a week. Since the arrival of this technology, thereare now 18 different fractional technologies with a variety of wavelengths,including the 10,600 nm CO2 laser.

20 CHAPT E R 1

Photomechanical Tissue Response

Pulsed lasers can be mechanically engineered to create shock waves orhigh-amplitude pressure waves in tissue.34 These pressure waves canresult in mechanical stress or photoacoustic reactions sufficient to breakapart calculi or stones in the bladder or ureter. Lasers like the Q-switchedlaser shown in Figure 1–18 can also be pulsed a billionth of a second pulse

MicrothermalZones ofHeat

Figure 1–17 Fractional laser technology creatingmicrothermal zones (MTZ) of heat into the tissue.

Figure 1–18 Q-switched YAG laser commonly used for tattoo removal.Courtesy of Medlite Hoya Con Bio.

Caution:Even though the same

wavelengths may be used to

produce a photothermal response

to tissue, these tattoo removal

devices are completely different

laser systems. The Q-switched

devices are specifically designed,

researched, and regulated for

tattoo removal only. One cannot

use a thermal laser or IPL device

on a tattoo! Doing so can cause

scarring and hypopigmentation,

along with subsequent litigation.


width or duration to break up pigment and tattoo ink. With this extre-mely short pulse, the energy can be delivered at very high power den-sities (megawatts) to the targeted tissue. An acoustic shock wave isdelivered at the beam’s focal point and then travels away at the speed ofsound. The pressure wave then expands in all directions and causes amechanical breakdown of the melanin or tattoo dye. These Q-switcheddevices can raise the tissue temperature to 1000°C in a billionth of a sec-ond, fast enough to explode particles of tattoo ink or pigment granules.Clinically, one sees a whitening of the impact site due to a laser-stimulatedplasma reaction or localized gas formation in the epidermis and der-mis.35 It can take three to six weeks for healing and clearance of thefragmented particles by the body’s immune system white blood cells(macrophages).

Photochemical/PhotodynamicTissue Response

Photochemical or photodynamic therapy (PDT) utilizes a particularwavelength(s) of light that is reactive to a light-absorbing or photosensi-tive chemical compound. The reaction causes a biochemical response thatresults in cell death or damage due to the conversion from oxygen (O2) toa singlet oxygen (O). PDT research in the 1990s was conducted as a can-cer therapy technique to kill invasive or penetrating tumors. The mostcommon cosmetic use of this technology today is the topical applicationof ALA (Aminolevulenic Acid) to the skin of a client who is experiencingprecancerous or photodamaged skin changes. After a period of topicalapplication and incubation, the client is then fluoresced with a particularlaser wavelength, diffuse light source, or IPL. (See Figure 1–19.) Resultshave been demonstrated to be as effective as other conventional techni-ques. PDThas gained acceptance and popularity as a more precisemethodof targeting abnormal skin cells.36

Photoablative Tissue Response

Photoablative laser reaction is the process in which chemical bonds arebroken when tissue comes in contact with certain laser wavelengths.What is experienced is a clean ablation with virtually no thermal effectsto the targeted tissue. Excimer lasers in the ultraviolet wavelength oflight, from 180 nm to 250 nm, can be used for this purpose as seen in theLASIX procedure where the cornea is reshaped to correct refractivedisorders.

Photochemical orphotodynamic therapyA chemical reaction activated by light;

this reaction selectively destroys tissue.

22 CHAPT E R 1

INTENSE PULSED LIGHT

In the mid-1990s, the first polychromatic, high-intensity flashlamp wasFDA approved for cosmetic use. This filtered flashlamp was marketedas Intense Pulsed Light (IPL). Since its initial rocky development, IPLdevices have emerged as the gold standard of treatment of photodamagedskin.37 Due to technological advances, IPL’s clinical outcomes arebecoming increasingly equivalent to established cosmetic laser systems.They are presently even being coupled with lasers, light sources, andradiofrequency devices.

Due to the variety of skin chromophores, it makes sense to use abroadband light to treat the variety of skin abnormalities seen with photo-damaged skin. IPL can act like a laser from the perspective of photother-molysis. Lasers usually treat one chromophore with one monochromaticlight, while IPL can target multiple chromophores with a spectrum ofvisible and infrared light. Because IPL devices are now so versatile, theycan be used for treating a variety of vascular disorders, pigmented lesions,hair removal, and photodamaged skin.

RADIOFREQUENCY DEVICES

Radiofrequency (RF) energy is a form of energy that differs from light oroptical energy. It is based on alternating energy waveforms that producelocalized, non-specific heat into the epidermis and dermis. RF energy

Figure1–19 Photodynamic therapy. ALA application onan individual under LED lights for acne therapy.Courtesy of DUSA Pharmaceuticals, Inc.

Intense Pulsed Light(IPL)Machine that uses a variety of filters to

diminish areas of color, both red and

brown, on skin (also called FotoFacial®

or PhotoFacial®).

Caution:Remember IPL devices are Class

2 medical devices and numerous

injuries have been reported.

Education, hands-on training,

and demonstration of

competency is mandatory before

treating actual patients.


wavelengths can range from one millimeter to hundreds of meters fromone waveform crest to the next.

Types of Monopolar RF devices

Radiofrequency devices have commonly been used in the surgical arena forthe last 50 years for cauterizing bleeding vessels and reducing blood lossduring surgery. Radiofrequency energy production follows the principleof Ohm’s Law, which states that the impedance (resistance) to the move-ment of the electrons creates heat relative to the amount of energy (current)over time (seconds).38 Most traditional radiofrequency devices and somepresent-day cosmetic units are monopolar systems. (See Figure 1–20.)Monopolar systems use rapidly alternating electrical energy that createsresistance at the epidermis and then converts to heat. Unlike lasers, whichoperate on the theory of selective photothermolysis, radiofrequencydevices derive their clinical effects from the heat generated due to the tis-sue’s natural resistance.39Once it heats the area, the current travels the pathof least resistance and seeks out an exiting pathway from the body. Adispersing electrode (a grounding pad), is placed usually on the client’s

Figure 1–20 The effect of a monopolar versus a bipolar RF (radiofrequency) device. Courtesy ofLumenis® Ltd.

ImpedanceResistance to the flow of electrons.

MonopolarThese systems use rapidly alternating

electrical energy that creates resistance at

the epidermis and then converts to heat.

Dispersing electrodeA grounding pad, usually placed on the

client’s thigh or back at a point distant

from the treatment area.

24 CHAPT E R 1

thigh or back at a point distant from the treatment area. The electrical cur-rent then exits the body via the grounding pad and returns to the machine.

The other type of radiofrequency device shown in Figure 1–20 doesnot require a dispersing electrode. If the positive and negative electrodesare placed at opposite ends of a handpiece, forceps, or treatment head,then the current flows superficially in the path of least resistance fromone electrode to another. This is referred to as bipolar radiofrequencyenergy, because the current is contained within the treatment head anddoes not require a dispersing electrode. Bipolar radiofrequency technolo-gy is also being combined with lasers and light source for deeper penetra-tion into the tissue and, in theory, a more effective outcome.

LIGHT EMITTING DIODES(LED DEVICES)

In contrast to thermal laser, there is an exciting new technology of non-thermal, non-ablative cellular stimulation called photomodulation.Unlike other laser/light-based procedures that rely on heat and thermalinjury to improve the skin’s appearance, LED trigger a photobio-chemical response. The process involves using low-level light energy tomodulate or activate cellular metabolism. LED devices are designedto include panels of tiny diodes that are pulsed at an exclusive arraysequence. LED photomodulation can suppress collagenase, a collagen-degrading enzyme that can accelerate our skin’s aging process.40 LEDcan also stimulate the energy-producing mitochondria to enhance woundhealing and decrease the inflammatory response. LED devices arebecoming more accepted as an adjunct treatment for improving the signsof aging and bolstering collagen production.

CONCLUSION

Understanding the basic physics behind laser, light, and radiofrequencydevices is the essential foundation toward gaining competency with anyaesthetic system. As an astute aesthetician, one needs to understand thefundamental concepts of energy absorption along with the correspondingbio-tissue effects. This knowledge will guide you in every step of thedecision-making process: selection of the appropriate client, selection ofthe appropriate device, selection of appropriate parameters, and selectionof the appropriate safety control measures. Hopefully this chapter hasenabled you to appreciate the intensive research and development thathas painstakingly occurred throughout the years to develop today’s laserand light devices.

Bipolar radiofrequencyenergyIf the positive and negative electrodes are

placed at opposite ends of a handpiece,

forceps, or treatment head, then the

current flows superficially in the path of

least resistance from one electrode to

another.

PhotomodulationNon-thermal, non-ablative cellular

stimulation.

LED (Light EmittingDiode)A semiconductor diode that emits light

when an electrical current is applied to

the device.

ModulateActivate cellular metabolism.


> > > TOP 10 TIPS TO TAKE TO THE CLINIC

1. Laser is an acronym that means “light amplification by thestimulated emission of radiation.”

2. The Electromagnetic Spectrum of Radiation is made up of all formsof energy whose wavelengths extend from invisible infrared, tovisible light, to invisible ultrashort gamma waves.

3. Laser light is different from other forms of light due to itscharacteristics of coherency, collimation, and monochromaticity.

4. Fluence, or radiant energy, refers to the energy of the pulsed laserand is expressed in joules/cm2 ( J/cm2).

5. Laser light absorption is the physical process in which light energy isattracted to a chromophore and converted into heat.

6. Selective photothermolysis refers to light that delivers energythat is engineered to cause selective destruction of the designatedtarget.

7. Q-switched lasers can cause shock waves that cause photoacousticeffects sufficient to break apart dye tattoo particles.

8. Most cosmetic laser systems produce a photothermal effect totissue.

9. IPL devices emit a broadband, diffuse light source that is composedof visible and infrared wavelengths of light.

10. Radiofrequency devices use alternating energy waveformsthat produce localized, non-specific heat in the epidermis anddermis.

CHAPTER REVIEW QUESTIONS

1. List the three properties of lasers that are not shared by IntensePulsed Light.

2. What is the Electromagnetic Spectrum of Radiation?

3. Describe four laser–tissue interactions.

4. Discuss the concept of stimulated emission of radiation.

5. Describe the concept of selective photothermolysis.

6. Define the term irradiance.7. What is a LED device?

8. Define the two types of radiofrequency devices.

26 CHAPT E R 1

CHAPTER REFERENCES

1. Aesthetic Dermatology News. (2008, May/June), 30.2. Resinisch, L. (1996). Laser physics and tissue interactions.

Otolaryngologic Clinics of North America, 29(6), 893–913.3. Goldberg, D., Rohrer, T., Dover, J., & Alam, M. (2005). Lasers

and lights: Vascular, pigmentation, scars, medical applications, 1.Philadelphia: Mosby Elsevier Health Science.

4. JGMAssociates, Inc. (1993). Therapeutic Applications of AdvancedLaser Products, 1, Tutorials. Burlingham, MA: Author.

5. Rockwell, J. & Chamberlain, J. (2000).RLI:Medical users guide forlaser safety. Cincinnati, OH: Rockwell Laser Industries.

6. Ibid.7. Dennis, V., Crowgey, S., & Grimes, B. (1996). Laser series.

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