1.
Basics Of Lasers:

2.
Definition:
“LASER” is an acronym that stands for Light
Amplification by the Stimulated Emission of
Radiation.
Laser is an instrument that generates a beam of
light of a single wavelength or color that is both
highly collimated and coherent.

3.
Principle of laser:

4.
BASICS COMPONENTS OF LASER:

5.
History:
• The first functional laser (ruby, 694 nm) was
developed by Maiman in 1960.

6.
Characteristics of Laser Light:
Monochromatic: composed of a single wavelength or color.
Coherence: All the waves of light move together temporally and
spatially.
Collimation: where the transmission of light occurs in parallel fashion
without significant divergence, even over long distances.

7.
Electromagnetic Spectrum:

8.
Lasers Commonly used in Dermatology:
1. Argon Laser: 488/514 nm
2. Potassium-titanyl-phosphate (KTP): 532 nm
3. Copper bromide/vapour: 510/578 nm
4. Argon-pumped tunable dye (APTD): 577/585 nm
5. Krypton: 568 nm
6. Pulsed dye laser (PDL): 585/595 nm
7. QS ruby: (694 nm)
8. QS alexandrite: (755 nm)
9. QS neodymium (Nd):yttrium-aluminum-garnet
(YAG): 1064 nm
10. Erbium:YAG: 2940 nm
11.Carbon dioxide Laser: 10,600 nm
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9.
Terminology:
Power: The rate at which energy is emitted from a laser.
Watts.
Joule (J): A unit of energy used to describe the rate of
energy delivery.
Fluence: determines the amount of laser energy per unit
area and is expressed in joules/cm2.
Spot Size: The mathematical measurement of the radius
of the laser beam.

10.
Pulse: A discontinuous burst of laser as opposed to a
continuous beam.
Pulse Frequency: The rate at which pulses are generated. Is
expressed in pulses per second (Hz).
Pulse Duration: The "on" time of a pulsed laser. Measured in
terms of ms, μs, or ns.

11.
Irradiance: (power density) The rate at which energy
is delivered per unit area.
It determines the ability of a laser to incise, vaporize,
or coagulate tissue and is expressed in watts/cm2.

12.
Thermal Relaxation Time(TRT): time required for the
dissipation of 63% heat gained by the tissues (ms/μs) during
irradiation.
Thermal Damage Time(TDT): The time for the entire target
including the primary chromophore and surrounding target to
cool by 63%.
Focus: The exact point at which the laser energy is at peak
power
63%

13.
Chromophores in the Skin:
Are the selectively laser energy absorbing target molecules in the skin.
1. Endogenous chromophores:
• Melanin: UV -1200nm
• Hb: UVA, blue (400 nm), green (541 nm), Yellow (577nm)
• Collagen: Visible and near infra-red spectra
• Water: in the mid and far infrared regions
2. Exogenous chromophores: Such as tattoo ink.

14.
Classification of Lasers:
Laser are classified according to the nature of the amplifying
medium: gas, liquid(dye) or solid state:

15.
Modes Of Output:
• Continuous wave
• Quasi CW
• Pulsed

16.
Ablative Vs Non Ablative:
ABLATIVE: outer layers of skin are (removed) through
vaporization of the cells. Healing takes place by re-deposition
of collagen.
Egs:
Er: YAG
CO2 laser
NON-ABLATIVE: induce dermal neocollagenesis without
epidermal disruption,
KTP
Pulsed Dye
Nd: YAG

17.
FRACTIONATED LASER:
Laser beam is “fractionated” into a pattern where some parts
of the skin are targeted, and the other parts are left intact. A
grid like pattern appears on the skin.

18.
How Fractionated Lasers Work:

19.
Tissue optics:

20.
Tissue optics:
1. Reflection.
• 4–6% of light is reflected.
• Lowest when the beam is perpendicular.
2. Absorption. Depends on the properties
of the substance through which the light
passes.
Target molecules are called chromophores:
(1) Melanin
(2) Hemoglobin
(3) Water
(4) Collagen

21.
3. Scattering. Is the deviation of light by
non-uniformities in the medium
Eg: collagen in the dermis.
It reduces the energy available for
the target chromophores.
4. Transmission. Light that is not
Reflected, absorbed or scattered
passes to deeper tissue.

22.
Light–tissue interaction:
1)Photostimulation: Low energy lasers expedite wound
healing.

23.
2. Photodynamic change: uses topical or systemic
photosensitizers. Subsequent irradiation elicits a photo-
oxidative reaction and an immediate cytotoxic effect.

24.
3)Photo-thermolytic and Photo-mechanical Effect: works on
the principal of Selective photothermolysis: A concept
used to target chromophore based:
• on its absorption characteristics,
• the wavelength of light used,
• amount of energy delivered.
• the duration of the pulse,

25.
4. Photo
Acoustic Effect:

26.
Uses of Laser: Lasers
1. Hair Reduction: Long pulsed Nd:Yag (1064nm)
Alexandrite laser (755nm)
2. Hyperpigmentation:
(a) Epidermal Type Q switched, Nd:Yag (532nm)
PDL
Uses of Lasers:
(b) Dermal Type: Q switched Nd:Yag (1064nm)
(c) Mixed Type: Q-switched Ruby (694nm)
Chromophore: Melanin
Chromophore: Melanin

27.
(c) Large Vessel Telengiectasia
Krypton Laser (568nm)
Copper vapour Laser
3. Vascular Lesions:
(a) Port wine stain PDL
Alexandrite laser (755nm)
Q switched Nd:Yag (1064nm)
(b)Small calibre Telengiectasia PDL
Chromophore: Hemoglobin

28.
(4) Facial Rejuvenation:
(a) Ablative: CO2 laser(10,600nm)
Erb:Yag laser (2940nm)
(b) Non-Ablative:
PDL
Q-switch Nd:Yag (1064,532)
(5) Hypertrophic scars, warts,
benign neoplasm
PDL
(7) Acne PDL(6) Hemostasis CO2 Laser (10600nm)
(7) Laser Lipolysis: Nd: Yag Laser (1064nm)
Chromophore: Water

29.
(8) Tattoos:
(a) Blue/ Black Q-switched ruby,
Q-switched alexandrite
Q-switched 1064-nm Nd:YAG
(b)Green Q-switched ruby,
Q-switched alexandrite
(c) Red/ Orange/ Purple Q-switched Nd:YAG 532-nm
Chromophore: Tattoo Ink

30.
Cooling Systems:

31.
Cooling Systems:
Contact skin cooling
• Active
Copper, or sapphire tips:
For delivering longer pulse durations(>10 ms)
Provide pre, parallel and post laser cooling.
• Passive
Ice cubes:
Reduces inflammation post procedure.
Easy method.
Disadvantages: a waiting period
Melting water on the skin
Aqueous gels:
Not advised nowadays.
Cannot provide prolonged cooling.

32.
Non Contact Cooling:
1) Cryogen spray (liquid nitrogen):
(a) Not recommended now causes
cryonecrosis.
2) Pulsed cryogen spray (dynamic cooling device):
(a) Provides uniform cooling at -30C
(b) Method of choice
3) Forced refrigerated air:
(a) Delivers chilled air pre, parallel and
post procedure.
(b) By convection cooling.

33.
Preparing A Patient for Laser session:

34.
Patient selection:
1. Take History to find out:
• Immunocompromised status, esp diabetes
• Isotretinoin use.
• Active local or systemic infections especially recurring HS
infection. (Aciclovir or valaciclovir given 1 day prior to & 5–14
days post treatment)
• Tendency to keloid scarring.
• Personal or family history vitiligo.
2. Prophylactic antibiotics and antivirals for ablative procedure
3. To minimize post laser hyperpigmentation: 2 weeks before and 8
weeks after laser:
0.2% Retinoid preparation
2% Hydrocortisone
4% Hyroxyquinone
Anesthesia:
Topical anesthetic ointment under occlusion for 1 hr.
For ablative procedures, nerve blocks, tumescent anesthesia.

35.
Contraindications:
Absolute:
• Active bacterial,viral or fungal infections
• Unrealistic expectations
• Uncooperative pts
• Malignancy
Relative:
• Immunocompromised: Diabetes, HIV, Hepatitis B,C
• Oral isotretinoin
• Fitzpatrick skin 5-6 phototypes
• History of keloids.
• Patients taking gold salts are at the risk of chrysiasis (gold-
related skin discoloration).

36.
Precautions:

37.
Precautions:
The operating room:
• Laser room should be properly labeled.
• Hang eye goggles on the door.
• Unauthorized people should not be allowed.
• The room should not contain volatile substances such as
ether, alcohol .
• Plume evacuator: for larger lesions and warts.

38.
Safety measures for the patient:
• Special glasses should be used.
• Patient Consent
General measures:
• The surgeon should use the special glasses for the
particular laser.
• NEVER look directly into the laser source.
• NEVER point the hand probe in any direction, except
towards the area to be treated.

39.
SKIN CARE INSTUCTIONS AFTER LASER SURGERY:
• Do not rub, scratch or put pressure on the treated area
• Do not apply make-up in case of severe reaction.
• Avoid sunlight; Sun blocks can be advised.
• Ice bags to alleviate erythema and edema.
• Emollients to keep skin moist.
• Avoid irritants to the resurfaced areas
• Erythema and edema settle with topical corticosteroids

40.
SIDE EFFECT OF LASERS:

41.
Side Effects of Lasers:
(1) Immediate:
• Pain, burning sensation, edema
(2) Early:
• Oozing, crusting
• Secondary infection
• Reactivation of HS infection

42.
(3) Late:
• Dyspigmentation (hypo/hyper)
• Change in skin texture
• Demarcation lines
(in facial rejuvenation)
• Keloids and hypertrophic scars
• Scarring
• Milia
• Persistent erythema
• Dilated follicular ostia

43.
Nd: Yag Laser:
Nd:YAG (neodymium-doped yttrium aluminum garnet) is used
as a laser medium.
• Wavelengths: 532nm and 1064 nm,
• Penetrates 2-3mm into dermis
QSNd:YL 1064-nm:
Has the least absorption by melanin
Deepest penetration.
Effective for both epidermal and dermal pigmented lesions.
QSNd:YL 532-nm:
Is well absorbed by both melanin and hemoglobin.
Has superficial penetration,
Limited to treating epidermal pigmented lesions.

44.
Vascular lesions
Spider and thread veins
Varicose veins
Telangiectasia
Haemangioma
Pigmented lesions
Solar lentigines
Freckles
Nevus of Ota and Ito
Mongolian spot
Café-au-lait-macules.

45.
Hair removal:
Tattoos:

46.
Pulsed Dye Laser:
• Contains a rhodamine dye
• Wavelength: 585–600 nm.
• Pulse duration:0.45 ms (short-pulse)
1.5–40 ms (long-pulse PDL)
• Penetrates the dermis to a depth of 1.2 mm &
photocoagulates vessels of up to 100 μm in
diameter.
• Primary chromophore: hemoglobin.

47.
USES:
Cutaneous vascular lesions:
• Port wine stains
• Superficial hemangioma
• Telangiectasia
Non-vascular skin conditions
• Plane warts
• Pyogenic granuloma.
• Melasma
• Hypertrophic scars
• Nail psoriasis/plaque psoriasis

48.
Carbon Dioxide Lasers:
Active laser medium:
10–20% carbon dioxide,
Exists as Ablative nonfractinated laser
Ablative fractinated laser
Wavelength: 10,600 nm
Primary chromophore: Water

49.
• Depth: 20-30 µm of skin (epidermis and superficial
papillary dermis)
• In the healing period: re-epithelialization

50.
The following skin disorders can be treated with carbon
dioxide laser beams:
• Rhytides
• Acne scars
• Varicella and smallpox scars
• Verruca vulgaris/plana
• Junctional & compound Nevi
• Small syringomas