SECTIONS I. History of laser

history of laser, what is a laser, laser hair removal, laser fundamentals, examples of lasers used in health care

the first person who made the first light laser and was the first to use the word “laser”

gordon gould

what year was hair removal lasers approved for “permanent reductions” in the US by the FDA

1997

LASER stands for

light amplification by stimulated emission of radiation

a laser beam is generated by ____, which is stimulated emission repeated innumerable times resulting in a laser beam

aplificication

raised to an “excited” stage the electron naturally to return to its “resting’’ stage and does so by emitting a photon, what emission is this

spontaneous

electrons are stimulated repeatedly by energy and will force a proton to jump off in a wave form and return to their resting state, what emission is this

stimulated

determines the wavelength of the laser

lasing medium

used to excite or stimulate the lasing medium to produce the laser beam

power source

used to carry the laser beam from the unit to the hand piece and ultimately to the target

delivery system

light, visible and invisible ionizing and non ionizing is energy measured by wavelengths along a scale called the

electromagnetic spectrum

determined by the distance between two peaks and is measured in nanometers (nm)

wavelength

the higher on the spectrum of light the higher the attraction to ________

melanin and oxyhemoglobin

the lower on the spectrum the more attraction to ____ and less attraction to ______

melanin, water and oxyhemoglobin

_____ on the spectrum the shallower the penetration

lower

____ on the spectrum the deeper the penetration

higher

amount of time energy is directed to a target, measured in milliseconds or nanoseconds; also known as pulse duration

pulse width

maximum energy output is determined by

spot size characterisitics

large spot size allows for deeper penetration and

less scatter

smaller spot size results in a shallower penetration with

more scatter

measures the rate of energy per unit area or J/cm²

fluence

maximum fluence is determined by

pulse width, spot size and wavelength

time necessary for a target tissue to cool down by 50% through transfer of heat to surrounding tissue

thermal relaxation time (TRT)

STAR is

scattering, transmission, absorption, reflection

4 types of epidermal cooling are

bulk cooling - clear gel, chilled

contact cooling - through a window cooled by circulating water

cryogen spray- applied immediately before and after

air cooling- zimmer cooler

lasers produce a narrow beam of light in which all the light waves travel together with their peaks lined up in which is referred to as a

phase

considered the primary chromophore for all hair removal lasers

melanin

two types of melanin

eumelanin and pheomelanin

gives hair brown or black color

eumelanin

gives hair blonde or red color

pheomelanin

part of a molecule responsible for its color

chromophore

pigment is produced in a specialized group of cells known as

melanocytes

lasers are measured by their wavelengths in

nanometers (nm)

measured in nanoseconds, microseconds or milliseconds is the timing of the light energy

pulse duration

hair removal lasers have a spot size about the size of

3-18 mm

energy or fluence is measured in

joules per square centimeter (J/cm²)

488 or 514.55

turquoise /cyan or green

no longer used

agron

694.3

deep red

used on pale skin

ruby

755

near infrared

used on 1-4 skin types

alexandrite

810

near infrared

used on pale to medium

pulse diode array

1064

near infrared

used on 1-3 and darker complexions

Nd: YAG

400-1400

not a laser

1-3 or pale to medium

intense pulse light (IPL)

process that reduces the amount of laser energy that can be directed at the target tissue

scattering

residual light that has not been reflected, absorbed, or scattered will be transmitted into deeper structures like the subcutaneous tissue

tranmission

physical process in which light energy is converted by the target tissue into either heat, acoustic response, chemical reactions or cellular stimulation

absorption

4-6 % of natural light is reflected when it hits the skin at a 90 degree angle, mainly takes place at the stratum corneum

reflection

effects occur when the absorbed light energy within the chromophore is converted into thermal energy

photothermal

when extremely high energies get absorbed at short pulse durations, which lead to extremely rapid thermal expansion of the target

photomechanical

utilizes wavelengths of light that is reactive to light absorbing or photosensitive chemical compounds

photochemical

tattoo ink is the main _____ chromophore

exogenous

mainly absorbed by melanin and hemoglobin

visible and UV light

mainly absorbed by water

infrared light

two types of laser hazards

laser beam hazards and non laser beam hazards

laser beam hazards are associated with

eye and skin burns due to laser beam shining on a body

non laser beam hazards are assocaited with

laser equipment or hazardous substances released from the equipment

this type of eyewear should NOT be worn during high power beams but ONLY low power visible beams

alignment eyewear

where a class 3b or class 4 laser is used a ____ must be on staff

laser safety officer (LSO)