Practical Introduction to Laser Dermatology Vishal Madan Editor 123 Practical Introduction to Laser Dermatology Vishal Madan Editor Practical Introduction to Laser Dermatology Editor Vishal Madan Consultant Dermatologist, Laser and Mohs Surgeon Salford Royal NHS Foundation Trust, Stott Lane Salford UK ISBN 978-3-030-46450-9 ISBN 978-3-030-46451-6 (eBook) https://doi.org/10.1007/978-3-030-46451-6 © Springer Nature Switzerland AG 2020 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. 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This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Contents 1 Fundamentals of Lasers and Light Devices in Dermatology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Elizabeth Raymond Brown 2 Lasers for Vascular Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Giulia Rinaldi, Samira Batul Syed, and Vishal Madan 3 Pigment Specific Lasers and Light Devices . . . . . . . . . . . . . . . . . 91 Sanjeev Aurangabadkar 4 Epilation Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Samantha Hills and Daron Seukeran 5 Ablative Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Vishal Madan 6 Fractional Laser Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Sarah Felton and Vishal Madan 7 Radiofrequency Devices Including Fractional Radiofrequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 Ileana Afroditi Kleidona, Ali M. Ghanem, and Nicholas J. Lowe 8 Light Emitting Diodes and Low Level Laser Light Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 Caiwei Zheng, Ali Rajabi-Estarabadi, Melanie M. Hirsch, and Keyvan Nouri 9 Intense Pulsed Light in Dermatology . . . . . . . . . . . . . . . . . . . . . . 219 Sam Hills and Miguel Montero 10 Cosmeceuticals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 Rhonda Meys 11 Self-Assessment Questionnaire . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 Vishal Madan Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257 v 1 Fundamentals of Lasers and Light Devices in Dermatology Elizabeth Raymond Brown Historical Development of the Laser Table 1.1 summarises the historical landmarks in the development of laser devices. The theory describing the properties of light emit- The 1980s onwards saw a rapid development ted by the process of stimulated emission was pro- in lasers capable of delivering new wavelength posed by Albert Einstein in 1917 [1] but Einstein wavelengths, stable beam and output characteris- did not use the term laser in his publication. tics and devices that were more compact and effi- According to Hecht [2] the development of the cient. The growth in laser types mirrored the laser was ‘neither simple nor easy’ yet we take search for new applications and tailoring to spe- lasers and laser applications very much for cific interventions, e.g. wavelengths for improv- granted because they are so widely used in the ing absorption by a given target or depth of field of medicine, dentistry, veterinary, entertain- penetration. ment, commerce, industry and research. The first practical laser was demonstrated in 1960 by Theodore H. Maiman at the Hughes Properties of Light Research Laboratory in America [3], using a cyl- inder of synthetic ruby just 1 cm in diameter and Light is described as a wave-particle duality, 2  cm long in an arrangement that Maiman meaning it displays characteristics of waves and referred to as an optical maser. The foundation particles (Fig.  1.1). Beams of light being for this incredible achievement was made possi- reflected, diffracted or experiencing interference ble by the fundamental physics studies of Max are evidence of light travelling as a wave. Light Planck who in 1900 described light as a form of acting as a particle is evidenced by the photoelec- energy and presented the concept of quanta, for tric effect that causes a precise and specific which he received the Nobel Prize in physics in removal of materials such as ablation of corneal 1918 [4]. Planck’s work inspired Albert Einstein tissue by excimer lasers. Either concept may be to investigate the interaction of light with matter used depending upon the sense of scale, e.g. and in 1905 he too concluded that light delivers wavelength versus photon energy and both energy in discrete quantum particles which are descriptions are relevant to laser and light inter- now referred to as photons [5]. ventions and laser safety. For example, light as a wave is used to describe spectral output, i.e., the wavelength of the output beam, while light as a E. Raymond Brown (*) particle explains specific interactions with matter Laser Education Limited, Gainsborough, UK and tissues, i.e. tissue ablation. e-mail: [email protected] © Springer Nature Switzerland AG 2020 1 V. Madan (ed.), Practical Introduction to Laser Dermatology, https://doi.org/10.1007/978-3-030-46451-6_1 2 E. R. Brown Table 1.1 Historical landmarks in laser development Year Contributor Contribution 1917 Albert Einstein Proposed the conditions required for ‘stimulated emission’ of light. [5] 1957 Gordon Gould Proposed the conditions required for stimulated emission at visible wavelengths. [6] Acknowledged to be the first person to use the term ‘LASER’. Gould did not immediately patent his concepts and the ideas of Schawlow and Townes were patented first. 1958 Arthur Demonstrated a maser (microwave amplification by stimulated emission of radiation) Schawlow and using ammonia gas and microwave radiation. Their papers published in 1954 and Charles Townes 1958, led to patents on the theoretical requirements for designing ‘optical masers’. [7] While technically they invented the first laser it was referred to as an ‘optical maser’. 1960 Theodore Demonstrated the visible first laser using a rod of synthetic ruby with reflective Maiman [3] coatings on each end surrounded by a helical flashlamp. The publication Physical Review rejected Maiman’s original article (June 1960), but the scientific community later recognised it as a discovery that changed the world. 1960 Ali Javan [8] In 1959 Javan proposed the first gas laser and in 1960 demonstrated a helium-neon (HeNe) gas laser operating continuously rather than in pulses. The HeNe laser initially emitted in the near IR with the 632.8 nm (red) output discovered in 1962, making it one of the most popular early lasers in research and medicine. 1963 Zhores Alferov In 1963 Alferov and Kromer independently proposed the principles for semiconductor [9] heterostructures to be used to emit light. It took until the 1970s to produce stable, room Herbert temperature operated devices and semiconductor lasers are now the commonly used Kroemer [10] laser types. 1964 William Bridges Bridges was the first to report ten different laser transitions, including blue and green [11] light, from an argon gas laser. 1964 Kumar Patel Patel demonstrated the first carbon dioxide (CO) laser showing it to be capable of 2 [12] very high continuous-wave and pulsed power output at very high conversion efficiencies. 1964 James Geusic Demonstrated the first neodymium yttrium aluminium garnet (Nd:YAG) laser. Initially et al. [13] developed in 1961 neodymium-based lasers required the inclusion of yttrium aluminium garnet (YAG) to emit stable and reliable outputs. 1968 Peter Sorokin Demonstrated the first laser using an organic dye as the active medium. et al. [14] 1970 Nikolai Basov Basov is generally credited with the initial development of a gas laser using a xenon et al. [15] dimer. However, research groups including IBM developed the technology using noble gases for a family of devices known as excimer lasers. Initially designed for photoetching materials, applications extended to human tissue in particular corrective eye surgery. 1983 Rox Anderson Published a paper describing thermal confinement of heat to target tissue thus allowing and James precise and selective destruction through a process termed selective Photothermolysis. Parish [16] Their publication significantly advanced the understanding of laser and light-tissue interactions. Light as an Electromagnetic Wave Electromagnetic radiation (EMR) is the con- tinuous range of energies that extends from For safe and effective practice, it is essential X-radiation to radio waves. Although these forms that clinicians understand the different types of of energy are different from one another, they all lasers, the differences between laser and travel through space as waves thus exhibiting intense light sources (ILS), also known as wavelike properties. A key feature of EM waves intense pulsed light (IPL (TM)) devices and is that they propagate and move without a propa- the properties of laser and light beams. The gation medium and hence can travel the vast starting point is to understand electromagnetic distances of outer space. The electromagnetic radiation (EMR) and the electromagnetic (EM) spectrum is the term used to describe the range of spectrum. EMR (Fig. 1.2). 1 Fundamentals of Lasers and Light Devices in Dermatology 3 LIGHT PHOTONS Evidenced by Wave Particle Evidenced by interference effects photoelectric effects Size Energy Wavelength λ Ephoton= hf Fig. 1.1 Illustration of the concept of the wave-particle duality of light High Frequency Low Frequency 1018 Hz 1015 Hz 1012 Hz 109 Hz 106 Hz 1pm 1nm 1µm 1mm 1m 1km Shorter Wavelength Longer Wavelength 10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 0 101 102 103 104 E L B X-RAYS ULTRAVIOLET VISI INFRARED MICRO WAVES RADIO WAVES OPTICAL SPECTRUM 180 nm 1 mm UV-C UV-B UV-A VISIBLE SPECTRUM IR-A IR-B IR-C Fig. 1.2 Illustration of the concept of the electromagnetic (EM) spectrum 4 E. R. Brown Fig. 1.3 Illustration of the concept of light as an electromagnetic (EM) Wavelength wave l Electric field variation Magnetic field variation Many of the properties that electromag- Table 1.2 Divisions of the Optical Region of the EM netic radiation demonstrates including reflec- spectrum [17] tion, refraction and diffraction are explained Region of optical Wavelength by considering a propagating wave compro- spectrum Division (nm/mm) mised of electric and magnetic fields which Ultraviolet (UV) UV—C 180– radiation— 280 nm are at right angles, both to each other and to ‘beyond’ violet UV—B 280– the direction of propagation as illustrated 315 nm (Fig. 1.3). UV—A 315– In layman’s terms, EMR can be described in 400 nm several ways. For example: Visible radiation A sensation of 400– (VIS)—‘light’ violet coloured 780 nm∗ light through to red • by name e.g., microwave energy coloured light • by wavelength e.g., 755 nanometres (nm) Infrared (IR) IR—A (near IR) 780– quoted in fractions of a metre (m) radiation— 1400 nm • by frequency e.g., radio waves quoted in Hertz ‘Below red’ IR—B (mid IR) 1400– 3000 nm (Hz) IR—C (far IR) 3000 nm • by photon energy, e.g. amount of energy car- −1 mm ried by individual photons (E ). photon *The spectral regions defined by CIE are shorthand nota- tions useful in describing biological effects and may not The EM spectrum includes a specific wave- agree with spectral breakpoints for laser safety calcula- length range referred to as the optical spectrum tions. The visible range (light) is quoted as 400–700 nm for laser safety purposes that includes ultraviolet (UV), visible (light) and infrared (IR) radiation. The wave nature of EMR allows this range to be categorised into distinc- the visual response in human eyes and therefore is tive bands Table 1.2. described as invisible but lasers emitting UV or IR Laser and light practitioners should note that radiation still pose a potential hazard to eyes and ultraviolet and infrared radiation does not invoke skin. Equally the sensitivity of the human eye is not 1 Fundamentals of Lasers and Light Devices in Dermatology 5 uniform over the visible spectrum, being a smooth concept of stimulated emission to the known function of wavelength and differing between indi- effects of spontaneous emission and spontaneous viduals. For example, the human eye detects absorption [1]. The phenomenon of transferring approximately 1% of light at 690 nm (red) but only discrete amounts of photon energy to skin and 0.01% at 750 nm (near infrared), effectively mak- tissues subsequently led to the medical laser and ing wavelengths longer than 750 nm ‘invisible’ light interventions available today. unless the light source is extremely bright [18]. Characteristics of Electromagnetic Light as a Particle Radiation Light has been described as an electromagnetic Wavelength wave propagating through space yet the develop- The simplest way to think of optical radiation is as a ment of the laser would not have been possible beam that travels as a wave. Hence the term wave- without the realisation of the particle properties length, which for laser and light therapies is usually postulated by Planck as cited by Nauenberg [19]. quoted in micrometers (μm) or nanometers (nm). Planck observed that matter could only absorb or Wavelength is an important concept to under- emit energy in discrete amounts or quanta that stand because it: cannot be further sub-divided. The energy of an individual photon is related • identifies a particular region of the EM spec- to the frequency of the corresponding light wave trum, e.g., 635 nm (visible radiation) by the relationship: • determines the ‘colour’ of the beam, e.g., 532 nm = green light E=hf orE=hc/l (1.1) • determines the light-tissue interactions, e.g., transmission or absorption by tissues where • dictates the lens colour or lens material used E energy of the photon in Joules (J) in protective eyewear h the Planck’s constant (6.626 × 10−34) in Joule • relates to the amount of energy carried by the second waves. f photon frequency (Hz) λ wavelength Figure 1.4 illustrates wavelength defined as c speed of light (3.00 × 108 ms−1) the horizontal distance of two consecutive This relationship shows that photon energy troughs or crests on the wave, written as λ increases with increasing frequency which is (lambda) and expressed in metres (m). vital in the context of light-tissue interactions. For example, comparing photothermal effects Frequency induced by longer wavelength, lower frequency Electromagnetic radiation is described as an radiation, e.g. infrared, with photochemical inter- oscillating wave travelling through space. actions induced by shorter wavelength, higher Therefore an alternative way to describe light is frequency radiation, e.g. ultraviolet/blue light. by the frequency (f or ν) of oscillation of the Planck’s observations that electromagnetic electromagnetic field. The frequency of a wave radiation is quantised proved that light has both refers to the number of wave peaks (full wave- wave-like and particle-like properties and subse- lengths) that pass a given point in space every quently paved the way for the discovery of the second, expressed in cycles per second (s−1) or photon by Albert Einstein. His understanding hertz (Hz). that atoms and molecules gain energy by absorp- Wavelength and frequency are inversely pro- tion and lose energy by emitting photons led to portional, that is the shorter the wavelength the his 1917 publication in which Einstein added the higher the frequency as more wave peaks can