Lesson 1 Flashcards
What is laser light?
Converts light into energy for use in devices
What is sunlight?
A beam or ray of light that is made up of a variety of invisible and visible forms of electromagnetic energy (EM energy)
What is a wavelength?
It is measured from the distance of the top of one wave (amplitude) to the top of the next
What is light measured by?
It’s wavelength (in nanometers)
One wavelength equals
The distance between two successive wave crests or troughs
Ionizing radiation
Occurs at short wavelengths (<400 nm)
Strips electrons from transport media
Alters cellular function
Causes mutation on DNA (ex. x-ray, ultraviolet (UV) rays
Non ionizing radiation
can NOT strip the electrons from transport media
Can NOT alter cellular function
Greatest health risk is ocular (eye) damage ex. Medical lasers and IPL machines
Properties of laser light
Lasers have unique properties that are not seen in any other type of energy form
Normal white light, that form a flashlight or lightbulb is made up of a multitude of visible and invisible infrared wavelengths merge and create white light that can quickly disperse in space within a short distance
laser light can cause four different tissue effects on the skin which are :
- Absorption
- Reflection
- Transmission
- Scatter / Diffusion
Photothermolysis
The absorption of light by chromophores (hemoglobin, melanin or water)
The transformation of absorbed light into heat (thermo)
The breakdown of the cells (lysis)
Examples of chromophores
Melanin, collagen, hemoglobin, water
What are the 5 parameters for selective photolysis
- Wavelength
- Pulse width
- Exposure time
- TRT
- Fluence
Wavelength
The distance between two successive wave crests
Pulse width (pulse duration)
The amount of time the laser is emitted on the skin
measured in nanosecond and millisecond
Exposure time
Should be less than or equal to the time necessary for cooling of the target structure
TRT Thermal Relaxation time
The time required for it to cool down to the normal temp of the surrounding tissue
Fluence
The energy delivered per unit area
Process of selective photothermolysis
The use of light energy to target a particle that is in our body which absorbs light
These particles are called chromophores
photothermolysis is achieved by
Wavelength
Pulse duration / Pulse width
Exposure dose / joules
Photothermolysis: wavelength
Selective absorption - The longer the wavelength the deeper the penetration
Photothermolysis: pulse duration
Heat confinement
Pulse duration is measured in nanoseconds or milliseconds- it is the timing of the light energy or how long the laser is actually on the skin
Photothermolysis: exposure dose
Fluence refers to the energy of the pulsed laser beam
Expressed in joules per square centimetre (J/CM2)
Refers to energy x time
3 main chromophores
Melanin
Hemoglobin
Water
What are 5 important terms we will be using frequently as a technician
Wavelength Joules Pulse width TRT Cooling
Light transmits…
Energy
Or in other words: Electromagnetic wave that carries energy
400-700nm visible light
Briefly explain the creation of laser light
The creation lies within a machines general design, computer software, cooling system m and optics
In every laser device is a tube or optical resonator - the resonator contains a medium (usually a gas, solid or liquid) that is responsible for the creation of light
Gas medium can be made of: argon, carbon dioxide, helium- neon gas particles
Solid medium is usually a synthetic crystal made up of yttrium aluminum garnet (YAG) particles and then doped with certain elements such as holmium, neodymium, thulium or erbium electrons
Lasers are names in reference to their medium
Turning on a laser machine creates high-voltage electricity that stimulates an intense light source from within the machine
The electrons within the laser medium becomes stimulated by this electricity and then collide with mirrors placed on opposite ends of the laser tube and spontaneously produce identical photons
Photons travel at the same frequency, parallel to each other and in phase in a collimated, coherent, monochromatic beam of light
What does “LASER” stand for
Light Amplification Stimulated Emission Radiation
List Properties of laser light (3)
- Coherent light
- Monochromatic light
- Collimated light
Coherent light
All the light waves are travelling in the same direction and in unison with each other
Monochromatic light
Normal light contains all of the visible colours of light and appears white
When light is passed through a prism or water droplet, one can actually see the full spectrum of visible light in a rainbow
Laser light referred to as monochromatic mono means one it is made up of one way length and one colour and can be either visible or invisible
Each different colour of light acts differently when exposed to different tissue and will create a uniquenical effect
What is the difference between IPL and laser?
Laser is monochromatic
Lasers can only see one colour
IPL can see more colours and are colour coded
(Blue- acne - 420)
(green - pigment & vascular lesions)
Collimated light
Laser photons are coherent, parallel to each other and can travel long distances
Laser light that exits from a devices hand piece can fire across a room
This is why safety protection controls need to be in place
List some laser devices
Ruby 694 nm
Alexandrite 755 nm
Diode laser 810nm
ND YAG 1064
Tattoo removal
Q switched Ruby laser 694 nm
Q switched alexandrite laser 744nm
Q switched ND YAQ laser 1064 nm
Ruby 694 nm
Laser device
High melanin attraction
Best for skin types 1&2 (light skin)
Doesn’t penetrate as deep as other machines
Less effective for deep follicles and dark skins
Alexandrite 755 nm
Laser device
2nd highest melanin attraction
Effective for skin types 1 to 4
Uses cooling system - especially for darker skin type
Most have a built in cooling system
Diode laser 810 nm
Has a variety of pulse duration (pulse width)
Effective on all skin types 
Long term hair reduction
ND-YAG 1064
Lower melanin attraction
Safe for dark skin
Long pulse ND- YAG laser can penetrate 3-5 mm deep
Higher Fluence and aggressive cooling is needed in order to see the best result without damaging surrounding skin
Causes more discomfort due to deep penetration
Tattoo removal
Due to absorption curve of laser versus the different colours of tattoo ink, each colour may require a different laser for proper clearance
The result is not guaranteed and a fair amount of trauma to the skin is necessary for deep tones
Q- switched Ruby laser 694 nm
Clears green, black and blue pigment
Multiple treatments required
Q switched alexandrite laser 755 nm
Also clears green, black & blue pigment
Multiple treatments required
Q switched ND YAG Laser 1064 nm
Treats black and blue pigment
Has advantage over alexandrite because it can be used on darker skin types
Effective device
Blistering, bleeding and bruising are often side effects when using this laser
What is IPL?
Intense pulse light
Different from laser
It is a computer generated system, which emits a broad spectrum of light wave length from 420 to 1200 nm
Special cut off filters are used to block out wavelength of light below the filter number selected and only those wavelengths of light above the filter numbers to pass through
IPL is versatile
One wavelength is absorbed by a chromophore, heat is released
Can treat more than one chromophore at the same time
It is high intensity light source which emits polychromatic, noncoherent light
IPL has a broad wavelength spectrum (420-1200nm)
What does laser light emit?
Monochromatic, coherent light
What is the depth penetration of blue light?
Surface level
Only targets the epidermis
What is the depth penetration of yellow/ green light?
Targets the epidermis and dermis
What is the depth penetration of red light?
Hair follicle
Deepest penetration
Each hand piece is colour coded to its corresponding
Wavelength
Each wavelength will penetrate the skin differently
blue is the most superficial
red will penetrate deeper
Blue hand piece treats…
Acne
AC420
Green hand piece treats..
Pigmented and vascular lesions
DUAL VP
What does the yellow hand piece treat?
Skin rejuvenation
SR580
What does the red hand piece treat?
Hair reduction
HR635
Light intensity is defined by
The energy density (FLUENCE)
Fluence
Is measured in joules per centimetre squared (J/cm2)
It is how much energy/ heat is being delivered to the skin
Describe what happens if the clothing or skin is darker
The darker the clothing or skin, the more optical energy (light) is absorbed
Darker surfaces heat up faster, thus they require a lower Fluence
What are joules?
Joules are the unit of measurement used to describe the intensity (Fluence) of the light energy per cm2
Joules can be referred to as Fluence or light energy
What does Fluence or energy density refer to?
refers to the amount of optical light energy delivered to a certain area measured in joules per centimetres squared it defines the intensity of the light pulse
Pulse duration
The pulse duration/ pulse width determines the “aggressiveness” of the treatment and is often measured in milliseconds
(The unit of measurement can vary depending on the technology)
Shorter pulses are more aggressive
Longer pulses are less aggressive
Longer pulses are safer for
Dark skin and dark hair
Shorter pulses are more effective for
Light thin hair/ light skin
What is DPC technology
Dynamic pulse control
DPC technology offers your client a personalized treatment that cater to their needs effectively and safely
It is important to achieve a therapeutic temperature only in the targeted area, we’re leaving the surrounding tissue intact
DPC pulse types
Smooth pulse
(Less specific, little TRT)
Long pulse
(More specific, more TRT)
High pulse
(Very specific, most TRT)
When was selective photothermolysis developed & by who?
1983
Anderson & Parrish
What does TRT mean?
Thermal relaxation time
The time it takes the heat to conduct away from the lesion
Benefits of cooling
Higher cooling = higher specificity
Cooling slows heat conduction to the healthy tissue
Decreases heating rates on healthy tissue
The heating of the lesion is not effected
Contact cooling hand pieces prevents
Superficial skin burns
Also adds comfort to patients treatment
