Transcript Introduction to Medical Lasers

Introduction to Aesthetic
Laser Concepts
Brief Overview
Gregory T. Absten
The Laser Training Institute™
Professional Medical Education Association, Inc.
www.LaserTraining.org
What is a Laser?
A Laser is an Electro-Optical device that converts
electricity or ordinary light energy into intense
beams of pure colors of light.
It stands for:
Light Amplification
by the Stimulated Emission of Radiation.
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What is the Electro-Magnetic
Spectrum?
This is comprised of all the various
wavelengths of electromagnetic energy
(Radiation) that constitute light, electricity
& radio waves. It ranges from the very
small wavelengths of cosmic rays and xrays, to the long wavelengths of Radio
transmissions. Visible light is one part of
this range, and each color is a different
wavelength.
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What is the Electro-Magnetic
Spectrum?
Different types of Lasers produce unique
wavelengths of electro-magnetic energy,
that range from the short wavelength
ultraviolet lasers, through visible light, to
long infrared wavelengths. Each type of
Laser is different.
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What is the Laser Active Medium?
This is the material that actually produces
the energy within the laser. Ignoring
commercial marketing names for a
moment, the Laser is usually named after
this active medium.
The Carbon Dioxide Laser for instance uses
that gas as the active medium, which
emits an infrared wavelength of 10,600nm.
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Some Common Aesthetic Lasers &
Wavelengths
Name
Wavelength
Alexandrite
Diode
755nm infrared
Hair Removal
Variable 810nm-1400nm Hair Removal
Veins
578nm yellow
Vascular
511nm green
Pigmented lesions
585-595nm yellow
Vascular
1064nm infrared
Hair Removal
Veins
10,600nm infrared
Skin Resurfacing
CuBr
Pulsed Dye
Nd:Yag
CO2
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Example Use
Energy Concepts
WATTS – (Power) Rate of Energy Delivery,
but doesn’t say how much energy (Dose).
JOULES – (Dose) Amount of Energy
Delivered, but doesn’t say how fast (Rate)
Joules = Watts x Time, i.e.;
1 Joule = 1000 watts x .001 seconds
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Energy Concepts
POWER DENSITY – Spot Size & Power
Watts per Square Centimeter
(W/cm2)
Concentration of the Power within the spot size.
Analogous to a magnifying glass and the sun.
Small spots burn (or ablate) because they are
more intense. Large spots don’t burn as quickly
because they are less intense. Spot size will
change the power density faster than a change
in power.
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Energy Concepts
ENERGY DENSITY – Spot Size & Dose
Joules per Square Centimeter
(J/cm2)
Concentration of the total “Dose” of light
within the spot size. This considers both
the Power Density and length of time. It is
usually the treatment parameter for
Aesthetic Laser use – i.e. 25J/cm2
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Tissue Effects
Most Aesthetic Laser Tissue effects come from
heating of specific target tissues when the light
from the laser is selectively absorbed into that
target.
Dark materials absorb more light and therefore
generate more heat that light materials. Heat
causes tissue death (hair removal), or
inflammation (skin rejuvenation) at lower levels.
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Tissue Effects
Adverse Tissue Effects can occur when the
heat is not confined to the target tissue,
but is either absorbed by or conducts into
other skin components.
I.E.; Burns & blistering created in Laser Hair
Removal when the melanin in darker skin
absorbs the laser light as much or more as
the hair follicle.
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Eye Safety
Lasers can cause eye injury from direct or
scattered light from the beam.
Retinal Injuries may be caused by those
wavelengths that can pass through fluid
into the eye’s interior.
These include the Diode, Pulsed Dye,
Nd:Yag and CuBr lasers, among others.
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Eye Safety
Lasers can cause eye injury from direct or
scattered light from the beam.
Corneal (Surface) Injuries may be caused by those
wavelengths that do not pass through fluid and
are instead absorbed at the surface of the eye.
These include the CO2 and Er:Yag lasers, but the
Power Density must be sufficient to cause a
burn.
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Eye Safety
Laser Safety Glasses MUST be worn by patients
and personnel when they are within a hazardous
distance around the laser output.
Laser Glasses are labeled with both the
wavelength for specific lasers (i.e. 755nm for
Alexandrite) and the Optical Density (O.D.)
which indicates their level of protection.
(Typically an O.D. of 4-7 for most medical
procedures)
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Eye Safety
The Glasses provide sufficient protection to
allow you to safely treat patients by
filtering out the light REFLECTED back
from the patient’s skin.
Laser Glasses are NOT guaranteed to
provide protection against DIRECT
impacts into the eyes. Never point the
Laser Output into anyone’s eyes.
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More Information

Laser Training – www.LaserTraining.org
Professional Medical Education Assn.

Laser Certification – www.LaserCertification.org
National Council on Laser Excellence

Professional Society – www.ASLMS.org
American Society for Laser Medicine & Surgery
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