As the title mentions, learn how LASER's are useful for cosmetic and non cosmetic purposes. This is a purely medicine based topic. Not described in lay man terms.

1. Application of LASER in Dermatology
Vivian Dsouza, FMMC, Mangalore

2. Dr Leon Goldman
Father of Laser Medicine
and Surgery

5. TYPES OF LASER MEDIA
GAS LIQUID SOLID
Argon
Carbon dioxide
Copper vapour
Helium-neon
Krypton
Xenon chloride
Rhodamine dye
dissolved in
organic solvent
Crystal
•Alexandrite
•Erbium doped yttrium
aluminium garnet (YAG)
•Holmium doped YAG
•Neodymium doped YAG
•KTP
•Ruby
Semiconductor diode
•Aluminium
•Gallium
•Arsenide

6. EXCIMER LASER NON-LASER LIGHT SOURCES
•Name is derived from the
terms excited and dimers.
•Use reactive gases, chlorine
and fluorine mixed with inert
gases such as Argon, Krypton
or Xenon.
•When electrically stimulated a
pseudo-molecule (dimer) is
produced.
•Dimer produces light in the UV
range.
•Intense pulse light
•Non coherent light within 500-
1200nm.

7. Chromophores
• These are absorbing molecules.
• Exhibit characteristic bands of absorption at
certain wavelengths.
• Three primary skin chromophores are :
 Water
 Haemoglobin
 Melanin

8. Chromophores in human skin – absorption spectra
of Haemoglobin, melanin and water

9. Penetration of LASER depends upon :
• Absorption and scattering
• Depth of penetration increases with wavelength
• Amount of scattering is inversely proportional to
wavelength.

10. Other factors include
• Thermal interactions such as
photocoagulation and photo-vaporization.
• Thermal relaxation time
• Photochemical ablation
• Selective photothermolysis
• Skin cooling

11. Application of LASER
principles

12. Ablative (Vaporizing) Skin Resurfacing
The ablative lasers are far-IR
 Carbon dioxide
 Erbium YAG
Chromophore – water
Very useful for treating
1. Photoaging
2. Scars
3. Epidermal nevi
4. Seborrheic keratoses
Complications : scarring, hyper pigmentation, delayed
onset permanent hypo pigmentation, prolonged
erythema, bacterial, viral and fungal infections.

13. Treatment of vascular lesions
A peak absorption of oxyhaemoglobin occurs at
577nm within the yellow spectrum.
1. Flashlamp-pumped pulse dye lasers (PDLs) with
pulse durations ranging from 0.45-40 ms
2. Pulse neodymium YAG lasers
3. Alexandrite lasers
 Hypertrophic lesions
 PDL resistant vascular lesions
4. Copper vapour or copper bromide lasers

14. 5. Potassium titanyl phosphate (KTP) lasers
Complications :
• Purpura as a result of microvascular
damage
• Subsequent thrombosis
• Delayed appearance of vasculitis

15. PROLIFERATING
HEMANGIOMA

16. Interactions during treatment of
pigmented lesion and tatoos
• Red and near IR lasers are most selective
• Mechanism :
a) Treatment of tattoos with Q switched lasers,
fragments the ink particles and selectively kills
pigment containing cells
b) This is associated with resultant ink particle
release
c) Subsequent removal of tattoo particles can occur
via an epidermal crust and/or lymphatic
transport, and some particles are re-
phagocytosed by dermal cells

17. • LASER commonly used are
1. Q-switched ruby
2. Alexandrite lasers
3.Q-switched Nd:YAG laser
Other conditions
• Lentigines
• Nevus of ota
• Cafe-au-lait macules
• Melanocytic nevi
• Side effects : pigment and textural changes, allergic reactions, ink
darkening, tissue aerosolization with possible infectious particles.

18. Interactions during Hair
removal
• Red to near IR region of the spectrum (deeply
penetrating)
• High energy
• Mechanism : damage to follicular stem cells in
the bulge region of the outer root sheath and/or
the dermal papilla at the base of the hair follicle
TEMPORARY HAIR LOSS PERMANENT HAIR LOSS
Induction of catagen which can occur
at very low fluences.
Miniaturization to produce vellus like
hairs.
An 810nm diode laser source
intended for home use
Complete degeneration with local
fibrosis.

19. Interactions during non-
ablative skin rejuvination
• Non-ablative facial facial rejuvination
• Fine lines
• Non-dynamic rhytides
• Mid-IR lasers
1. 1320nm Nd:YAG
2. 1450nm diode
3. 1520nm erbium:glass lasers
4. IPL sources
MECHANISM:
These work by subtle thermal effects on the
dermis, presumably stimulating a wound healing
response.

21. Fractional Photothermolysis
Thousand of nearly visible, microscopic
zones of thermal injury are created
Stimulating turnover
Remodelling of both – epidermis and the
dermis

22. NON ABLATIVE FP ABLATIVE FP
Uses focused mid-IR laser
microbeams to create a
pixilated pattern of small
columns of thermal damage
called microthermal
treatment zones
uses carbon dioxide or erbium
lasers to vaporize a similar
pattern of vertical channels
that can extend deeply into
the skin
USES :
•Scars
•Fine rhytides
•Telengiectasias
•Dermatoheliosis
•Poikiloderma

23. LASER based Diagnostics
1. Optical coherence
tomography
- Near IR
- low coherence light
- used for high
resolution cross
sectional imaging of
the body tissues

24. 2. LASER confocal microscopy
- Captures light scattered or emitted from a
thin plane “section” inside the skin.
- Since histochemical stains are not used
confocal microscopy of skin tumors reveal
diagnostic features that are different from
those of conventional histology.
- Microvascular blood flow and trafficking of
lymphocytes can be observed.

25. BIOPSY OF HUMAN SMALL INTESTINE
VISUALIZED WITH A CONFOCAL LASER
SCANNING MICROSCOPE

26. THANK YOU 